NOVEL COLLOID SYNTHETIC VECTORS FOR GENE THERAPY

Abstract: Non-naturally occurring vector for gene therapy are provided, comprised of chemically defined reagents, where the vector is self-assembling and where the vector comprises (1) a core complex comprising a nucleic acid and (2) at least one complex forming reagent, where the vector has fusogenic activity. The vector optionally may contain reagents permitting fusion with cell membranes and nuclear uptake. The vector also may contain an outer shell moiety that is anchored to the core complex, whereby the outer shell stabilizes the complex, protects it from unwanted interactions and enhances delivery of the nucleic acid into a target tissue or cell. The outer shell optionally may be sheddable, that is, it may be designed such that it dissociates from the vector upon entry into the target cell or tissue.

Description: NOVELCOLLOID SYNTHETICVECTORS FORGENE THERAPY BACKGROUND OF THE INVENTION Field of the Invention This invention provides compositions and methods for ex vivo, local, and systemic nucleic acid delivery. Description of the Related Art A critical requirement for the success of gene therapy is the ability to deliver the therapeutic nucleic acid of interest to the target tissue and cell types without substantial distribution to non-target tissues. A variety of synthetic molecules have been tested for their ability to deliver nucleic acids into cells, i.e. synthetic vectors. Conventional approaches to delivery of synthetic vectors has tended to concentrate on use of cationic lipid or cationic polymer-based systems. See, for example, Barron, et al, Hum. Gene Then 9:315-323 (1998),; Gao et al., Gene Therapy 2:710 (1995); Zelphati et al, J. Controlled Release 41:99 (1996)) or cationic polymers (Boussif etal, Proc. Natl, Acad. Sci. U. S. A. 92:7297 (1995)); Goula et al, Gene Therapy 5:1291 (1995)); Chemin, et al, J Viral Hepat 5:369 (1995)); Kwoh et al, Biochim. Biophys. Acta 1444:171 (1999)); Wagner, J. Controlled Release 53:155 (1998)); and Plank etal, Hum. Gene. Ther. 10:319 (1999)). Complexes of plasmid DNA encoding proteins with cationic lipids or cationic polymers (respectively referred to as "lipoplexes" and "polyplexes") transfect cells to give most efficient protein expression usually when the net charge on the complex is positive (charge ratios (+/-) greater than 1). Similarly, antisense or ribozyme oligonucleotides, with a sequence specific for an mRNA encoding a protein, complexed with similar or identical reagents can be delivered to cells in culture to give most effective inhibition of the specified protein usually when the net charge on the complex is positive. Some other preparations for nucleic acids developed include conjugates of polycations such as polylysine with targeting ligands such as FGF2 protein, liposomes encapsulating the nucleic acid in the internal entrapped aqueous phase, enveloped virus fused to liposomes encapsulating the nucleci acid such as the so-called HVJ-liposome, and a variety of emulsion preparations where the nucleic acid is sequestered into the non-aqueous phase of an emulsion or microparticle. Despite a variety of preparations, in most cases, though, the nucleic acid is bound into a colloid complexes by a complexation or encapsulation method. Many efforts have been made to prepare compositions that can provide delivery vectors for plasmids, oligonucleotides, and other forms of nucleic acids for the purpose of attaining a desired pharmacological benefit but to date these preparations still lack in vivo stability, specificity for target tissues and cells, and the capacity to provide adequate level of nucleic acid activity in the target tissues and cells. The mechanism by which these colloidal complexes are internalized is not understood, but is thought to depend on net charge in the complex and it is assumed that the positive surface charge of the complex and the negative surface charge of the cells play a major role in cellular uptake of the complexes as well as many other interactions with biological systems. A major disadvantage of lipoplexes and polyplexes is their tendency to interact nonspecifically with a wide variety of cells, contributing to several unwanted effects. In addition, the complexes can interact electrostatically with negatively charged proteins and other components in serum, leading to surface modification or destabilization of the complexes and other unfavorable effects or cellular interactions. A further problem with conventional complexes is their lack of colloidal stability. This instability results in aggregation of the complexes into large particles, especially at or near neutral charge ratios, and causes difficulty with long term storage. A number of approaches have been tried to overcome this problem. For example, one of the simplest approaches is by surface modification with a steric polymer such as poly(ethyleneglycol) (PEG). (Scaria et al., 1999, Program of the American Society of Gene Therapy meeting held at Washington D.C. on June 9- 13, p221a, abs# 878, Meyer etal, 1998, /. Biol. Chem. 273,15621-15627; Choi et al, 1998, Bioconjug. Chem. 9,708-718; Choi et al, 1998, /. Controlled Release 54,39-48; Kwoh et al, 1999, Biochim. Biophys. Acta 1444,171-190; Vinogradov etal, 1998, Bioconjug Chem 9:805-12; Zelphati tα/., 1998, Gene. Ther. 5, 1272-1282; Phillips, 1997, International Business Communications meeting held at Annapolis, Maryland on June 23-24, 1997; and Woodle et al, 1992, Biophys. J . 61, 902-10; E. Schacht et al, WO 9819710). A steric coating on the surface of the complex can enhance colloidal stability. Such steric coatings also minimize interactions with target and non-target tissue and cells as well as serum components, an undesired effect in the case of target tissues and cells. Modification of lipoplexes and polyplexes with PEG (PEGylation), however, has a significant deleterious effect on the biological activity of the complex. In addition to the desirable effect of inhibiting non-specific and unwanted binding to the cell surface, use of a steric surface may adversely impact binding to target tissues and cells. Furthermore, it may adversely impact subsequent steps in the DNA delivery process once binding to target cells has occurred. For example, PEGylation leads to poor overall levels of expression of the protein encoded by the DNA component of the complex (Scaria and Philips supra). Schacht et al. (WO 9819710) state that a particularly advantageous construction method involves stepwise construction first of nucleic acid complexes with cationic polymer molecules followed by a second step where the cationic polymer molecules are covaently coupled to a hydrophilic polymer block or to one or more targeting moieties and/or other bioactive molecules. A self-assembled hydrophilic polymer coating is constructed using A-B type linear block copolymers and such coatings can provide stabilization, though the complexes thus formed often still are destabilized quite quickly. Accordingly, Schacht describes a 2-stage procedure for assembly of the complexes where hydrophilic polymer and targeting moieties or other bioactive molecules are covalently attached to a preexisting colloid, i.e. particle. In addition, the covalent attachment of the hydrophilic polymer uses a polymer having multivalent covalent attachments so that cross- linking occurs in the surface coating of the complex. Such complexes have a number of limitations. Importantly, this kind of construction inevitably results in many different chemical structures which have significant differences in their activities including both desired and undesired ones. Furthermore, control of the amounts of each structure produced is difficult if not impossible. Importantly, the first hydrophilic polymer coupling events form a rudimentary steric coat that reduces the further occurance of coupling reactions so that the process becomes self-limiting. When greater amounts of surface bound polymer are needed than the self-limiting coupling permits then the resulting coat is badequate. Furthermore, a complete control over the coupling reaction in terms of which chemical species are formed is very difficult, if not impossible, when the conjugates are formed on the surface of a preexisting particle. Yet further difficulties are a need to protect from unwanted reactions or conjugations to the nucleic acid component but which is not easily fulfilled. Still other difficulties with a complex prepared with a 2-step method is a requirement that the core complex be prepared at a positive surface charge. Finally, when a complex successfully reaches a target tissues and cell, it must be able to bind efficiently with the target tissues and cell membrane and deliver efficiently the nucleic acid contents to the intracellular compartment where its activity can be exerted. Conventional complexes tend to perform these steps only poorly, leading to inefficient and/or inadequate levels of gene expression. It is apparent, therefore, that gene delivery vectors having improved target specificity and in vivo stability and which are relatively homogenous while being comprised of chemically defined species are greatly to be desired. In particular, it is desirable that the stable gene delivery vectors have an improved outer steric layer that provides enhanced target specificity, in vivo and colloidal stability, and enhanced target specificity. Furthermore, it is desirable that the vectors demonstrate improved cell entry and intracellular trafficking permiting enhanced nucleic acid therapeutic activity such as gene expression. SUMMARY OF THE INVENTION It is therefore an object of the invention to provide a non-naturally occurring vector for gene therapy comprised of chemically defined reagents, where the vector is self-assembling and where the vector comprises (1) a core complex comprising a nucleic acid and (2) at least one complex forming reagent, where the vector has fusogenic activity. The vector optionally may contain reagents permitting fusion with cell membranes and nuclear uptake. The vector also may contain an outer shell moiety that is anchored to the core complex, whereby the outer shell stabilizes the complex, protects it from unwanted interactions and enhances delivery of the nucleic acid into a target tissue or cell. The outer shell optionally may be sheddable, that is, it may be designed such that it dissociates from the vector upon entry into the target cell or tissue. It is a further object of the invention to provide methods of making these vectors, pharmaceutical compositions comprising the vectors, and methods of using the vectors and pharmaceutical compositions to treat patients. In accordance with these objects there has been provided a non-naturally occurring gene therapy vector comprising an inner shell comprising (1) a core complex comprising a nucleic acid and at least one complex forming reagent where the vector has fusogenic activity. The vector may further comprise a fiisogenic moiety. The fusogenic moiety may comprise a shell that is anchored to the core complex, or the fusogenic moiety may be incorporated directly in the core complex. In another embodiment, the vector comprises an outer shell moiety that stabilizes the vector and reduces nonspecific binding to proteins and cells. The outer shell moiety may comprise a hydrophilic polymer. In another embodiment, the vector comprises a fusogenic moiety. The outer shell moiety may be anchored to the fusogenic moiety, or may be anchored to the core complex. In yet another embodiment, the vector may comprise a mixture of at least two outersheU reagents. The outersheU reagents may each comprise a hydrophilic polymer that reduces nonspecific binding to proteins and ceUs, and wherein the polymers have substantially different sizes. In still another embodiment, the vector may contain a targeting moiety that enhances binding of the vector to a target tissue and ceU population. The targeting moiety may be contained in the outer sheU moiety. In yet another embodiment, the complex-forming reagent is selected from the group consisting of a lipid, a polymer, and a spermine analogue complex. The complex-forming reagent may be a Upid selected from the group consisting of the Upids shown in Figures 2.1 and 2.2. In particular, the complex-forming Upid agent may be is selected from the group consisting of phosphatidylcholine (PC), phosphatidylethanolamine (PE), dioleoylphosphatidylethanolamine (DOPE), dioleoylphosphatidylcholine (DOPC), cholesterol and other sterols, N-l-(2,3- dioleyloxy)propyl-N,N,N-trimethylammonium chloride (DOTMA), 1,2-bis (oleoyloxy)-3-(trimethylammonia) propane (DOTAP), phosphatidic acid, phosphatidylglycerol, phosphatidylinositol, glycoUpids comprising two optionaUy unsaturated hydrocarbon chains containing about 14-22 carbon atoms , sphingomyelin, sphingosine, cera ide , terpenes, cholesterol hemisuccinate, cholesterol sulfate, diacylglycerol, 1, 2-dioleoyl-3-dimethylammonium ropanediol (DODAP), dioctadecyldimethylammonium bromide (DODAB), dioctadecyldimethylammonium chloride (DODAC), dioctadecylamidoglycylspermine (DOGS), l,3-dioleoyloxy-2-(6- carboxyspermyl)propylamide (DOSPER), 2,3-dioleyloxy-N-[2- (sperminecarboxamido)ethyl]-N,N-dimethyl - 1 -propanaminium trifluoroacetate (DOSPA or Lipofectamine7), hexadecyltrimethyl-ammonium bromide (CTAB), dimethyl-dioctadecylammonium bromide (DDAB), 1, 2-dimyristyloxypropyl-3- dimethyl-hydroxy ethyl ammonium bromide (DMRTE), mpalnύtoylphosphatidylethanolamylspermine (DPPES), dioctylamineglycine- spermine (C8Gly-Sper), dihexadecylamine-spermine (C18-2-Sper), aminocholesterol-spermine (Sper-Chol) , 1 - [2-(9(Z)-octadecenoyloxy)ethyl]-2- (8(Z)-heptadecenyl)-3-(2-hydroxyethyl)imidazoUnium chloride (DOTIM), dimyristoyl-3-trimethylammonium-propane (DMTAP), 1.2-dimyristoyl-sn-glycero- 3-ethylphosphatidylcholine (EDMPC or DMEPC), lysylphosphatidylethanolamine (Lys-PE), cholestryl-4-aminoproprionate (AE-Chol), spermadine cholestryl carbamate (Genzyme-67), 2-(dipalnύtoyl-l,2-propandiol)-4-methylimidazole (DPIm), 2-(dioleoyl-l,2-propandiol)-4-methylimidazole (DOIm), 2-(cholestryl-l- propylamine carbamate)imidazole (Chlm), N-(4-pyridyl)-dipalmitoyl-l,2- propandiol-3-amine (DPAPy), 3β-[N-(N',N- dimethylaminoethane)carbamoyl]cholesterol (DC-Choi), 3β-[N-(N',N',N - trimethylaminoethane)carbamoyl] cholesterol (TC-CHOL-gamma-d3), 1,2- dioleoyl-sn-glycero-3-succinate, l,2-dioleoyl-sn-glycero-3-succinyl-2-hydroxethyl disulfide ornithine conjugate (DOGSDSO), l,2-dioleoyl-sn-glycero-3-succinyl-2- hydroxethyl hexyl orithine conjugate (DOGSHDO), N,N^N m -tetramethyl- N^^N^-tetrapalmityolspermine (TM-TPS), 3-tetradecylamino-N-tert-butyl-N- tetradecylpropionamidine (vectamidine or diC14-amidine), N-[3-[2-(l,3- dioleoyloxy)propoxy-carbonyl]propyl]-N,N,N-trimethyla mmonium iodide (YKS- 220), and 0,O -Ditetradecanoyl-N-(alpha-trimethylammonioacetyl)diethan olamine chloride (DC-6- 14). The complex forming reagent also may be a compound of formula I where m is 3 or 4; Y signifies a group -(CH 2 ) n -, in which n is 3 or 4, or may also signify a group -(CH 2 ) n- , in which n is an integer from 5 to 16, or may also signify a group -CH 2 -CH=CH-CH 2 -, if R 2 is a group -(CH 2 ) 3 -NR R 5 and m is 3; R 2 is hydrogen or lower alkyl or may also signify a group -(CH^-NR t Rs if is 3; R 3 is hydrogen or alkyl or may also signify a group -CH ∑ -CH -X'J-OH, if R 2 is a group -(CH^-N tRs and m is 3; X and X', independently of one another, signify hydrogen or alkyl; the radicals R, Ri, i and R 5 , independently of one another, are hydrogen or lower alkyl; with the proviso that the radicals R, Rj, R 2 , R 3 and X cannot aU together signify hydrogen or methyl, if m is 3 and Y signifies a group -(CH 2 ) 3 -; and their pharmaceuticaUy acceptable salts. In a further embodiment, the complex forming reagent comprises a mixture of at least two complex forming reagents. In a stiU further embodiment, the complex forming reagent possesses one or more additional activities selected from the group consisting of cell binding, biological membrane fusion, endosome disruption, and nuclear targeting. In other embodiments, the nucleic acid is selected from the group consisting of a recombinant plasmid, a repUcation-deficient plasmid, a mini- plasmid, a recombinant viral genome, a linear nucleic acid fragment, an antisense agent, a linear polynucleotide, a circular polynucleotide, a ribozyme, a cellular promoter, and a viral genome. The core complex also may further comprises a nuclear targeting moiety that enhances nuclear binding and/or uptake. The nuclear targeting moiety may be selected from the group consisting of a nuclear localization signal peptide, a nuclear membrane transport peptide, and a steroid receptor binding moiety. The nuclear targeting moiety may be anchored to the nucleic acid in the core complex. In still further embodiments, the fusogenic moiety comprises at least one moiety selected from the group consisting of a viral peptide, an amphiphdic peptide, a fusogenic polymer, a fusogenic polymer-Upid conjugate, a biodegradable fusogenic polymer, and a biodegradable fusogenic polymer-Upid conjugate. The fusogenic moiety mauy be a viral peptide selected from the group consisting of MLV env peptide, HA env peptide, a viral envelope protein ectodomain, a membrane-destabilizing peptide of a viral envelope protein membrane-proximal domain, a hydrophobic domain peptide segment of a viral fusion protein, and an amphiphiUc-region containing peptide, wherein the amphiphiUc-region containing peptide is selected from the group consisting of meUttin, the magainins, fusion segments from H. influenza hemagglutinin (HA) protein, HIV segment I from the cytoplasmic taU of HIV 1 gp41, and amphiphdic segments from viral env membrane proteins. In yet further embodiments, wherein the complex forming reagent is a polymer having the structure: wherein RI and R3 independently are a hydrocarbon or a hydrocarbon substituted with an amine, guanidinium, or imidazole moiety, wherein RI and R3 can be identical or different; and R2 is a lower alkyl group. The complex forming reagent also may be a polymer having the structure: wherein RI and R3 independently are a hydrocarbon or a hydrocarbon substituted with an amine, guanidinium or imidazole moiety, wherein RI and R3 can be identical or different; and R2 and R4 independently are lower alkyl groups. In other embodiments, the fusogenic moiety is a polymer having the structure: wherein RI is a hydrocarbon or a hydrocarbon substututed with an amine, guanidinium, or imidazole moiety; R2 is a lower alkyl group; and R3 is a hydrocarbon or a hydrocarbon substututed with a carboxyl, hydroxyl, sulfate, or phosphate moiety. The fusogenic moiety also may be a polymer having the structure: wherein RI is a hydrocarbon or a hydrocarbon substututed with an amine, guanidinium, or imidazole moiety; R2 and R4 independently are lower alkyl groups, and R3 is a hydrocarbon or a hydrocarbon substituted with a carboxyl, hydroxyl, sulfate, or phosphate moiety. The fusogenic moiety also may be a membrane surfactant polymer-Upid conjugate. The surfactant polymer-Upid conjugate may be selected from the group consisting of Thesit™, Brij 58™, Brij 78™, Tween 80™, Tween 20™, Cι 2 E 8 , CιβE 8 (C n E n = hydrocarbon poly(ethylene glycol) ether where C represents hydrocarbon of carbon length N and E represents ρoly(ethylene glycol) of degree of polymerization N), Chol-PEG 900, analogues containing polyoxazoUne or other hydrophihc polymers substituted for the PEG, and analogues having fluorocarbons substituted for the hydrocarbon. In still further embodiments, the inner sheU is anchored to the outer sheU moiety via a covalent linkage that is degradable by chemical reduction or sulfhydryl treatment. The inner sheU may be anchored to the outer sheU moiety via a covalent linkage that is degradable at a pH of 6.5 or below. The covalent linkage may be selected from the group consisting of In other embodiments.the outer sheU comprises a protective polymer conjugate where the polymer exhibits solubility in both polar and non-polar solvents. The polymer in the protective steric polymer conjugate may be selected from the group consisting of PEG, a polyacetal polymer, a polyoxazoUne, a polyoxazoUne polymer block with end-group conjugation, a hydrolyzed dextran polyacetal polymer, a polyoxazoUne, a polyethylene glycol, a polyvinylpyrroUdone, polylactic acid, polyglycoUc acid, polymethacrylamide, polyethyloxazoline, polymethyloxazoUne, polydimethylacrylamide, polyvinylmethylether, polyhydroxypropyl methacrylate, polyhydroxypropylmethacrylamide, polyhydroxyethyl acrylate, polyhydroxyethyloxazoUne, polyhydroxypropyloxazoline and polyaspartamide, and a polyvinyl alcohol. In still further embodiments, the vector contains a targeting element selected from the group consisting of a receptor Ugand, an antibody or antibody fragment, a targeting peptide, a targeting carbohydrate molecule or a lectin. The targeting element may be selected from the group consisting of vascular endothelial ceU growth factor, FGF2, somatostatin and somatostatin analogs, transferrin, melanotropin, ApoE and ApoE peptides, von WiUebrand's Factor and von WiUebrand's Factor peptides; adeno viral fiber protein and adeno viral fiber protein peptides; PD1 and PD1 peptides, EGF and EGF peptides, RGD peptides, folate, pyridoxyl, and sialyl-Lewis x and chemical analogues. In accordance with another object of the invention, there has been provided compounds having the formula I wherein m is 3 or 4; Y signifies a group -(CH 2 ) n -, in which n is 3 or 4, or may also signify a group -(CH 2 ) n -, in which n is an integer from 5 to 16, or may also signify a group -CH 2 -CH=CH-CH 2 -, if R 2 is a group -(CH 2 ) -NRιR5 and m is 3; R 2 is hydrogen or lower alkyl or may also signify a group if m is 3; R 3 is hydrogen or alkyl or may also signify a group -CH 2 -CH(-X')-OH, if R 2 is a group -(CH 2 ) 3 -NR 4 R 5 and m is 3; X and X', independently of one another, signify hydrogen or alkyl; and the radicals R, R ls j and R 5 , independently of one another, are hydrogen or lower alkyl; with the proviso that the radicals R, R ls R 2 , R 3 and X cannot aU together signify hydrogen or methyl, if m is 3 and Y signifies a group -(CH 2 ) 3 -; and their pharmaceuticaUy acceptable salts. In another aspect of the invention there has been provided a pharmaceutical composition comprising the vector described above, together with a pharmaceuticaUy acceptable diluent or excipient. In accordance with another aspect of the invention there has been provided a method for forming a self-assembling core complex of the type described above, where the method comprises the step of feeding a stream of a solution of a nucleic acid and a stream of a solution of a core complex-forming moiety into a static mixer, wherein the streams are spUt into inner and outer heUcal streams that intersect at several different points causing turbulence and thereby promoting mixing that results in a physicochemical assembly interaction. In accordance with still another aspect of the invention, there has been provided methods of treating a disease in a patient, comprising administering to the patient a therapeuticaUy effective amount of a vector as described above. In accordance with yet another aspect of the invention there has been provided a non-naturaUy occurring gene therapy vector comprising an inner sheU comprising: (1) a core complex comprising a nucleic acid and at least one complex forming reagent; (2) a nuclear targeting moiety; (3) a fusogenic moiety; and (4) an outer sheU comprising (i) a hydrophiUc polymer that stabilizes the vector and reduces nonspecific binding to proteins and ceUs and (u) a tageting moiety that provides binding to target tissues and ceUs, where the outer sheU is linked via a cleavable linkage that enables the outer shefl to be shed. Other objects, features and advantages of the present invention wiU become apparent from the foUowing detailed description. It should be understood, however, that the detailed description and the specific examples, while indicating preferred embodiments of the invention, are given by way of iUustration only, since various changes and modifications within the spirit and scope of the invention wiU become apparent to those skiUed in the art from this detailed description. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 show a diagram of non-naturaUy occurring vectors comprising (1) a core complex comprising a nucleic acid and at least one complex forming reagent and optionaUy reagents providing fusion with ceU membranes and nuclear uptake, and (2) an optional outer sheU anchored to the core complex optionaUy with a cleavable segment, and (3) an optional exposed Ugand anchored either to the core complex or the outer sheU (structure E). Figure 2.1-2.2 shows the chemical structures of cationic Upids. Figure 3.1-3.5 shows diagrams of structures formed by substimted aminoethanols and nucleic acids. Figure 4 shows smaU particle size distribution and homogeneity of complexes formed by substituted aminoethanols and nucleic acids. Figure 5 shows luciferase expression resulting from transfection of in vivo tissues foUowing intravenous administration to mice of core complexes formed from commerciaUy obtained cationic Upids, formed from substituted aminoethanols, and from commerciaUy obtained (ExGen) or synthesized (Lp500) linear PEI cationic polymers. Figure 6 shows GM-CSF expression resulting from transfection of in vivo tissues foUowing intravenous administration to mice of core complexes formed from commerciaUy obtained cationic Upids. Figure 7 shows luciferase expression resulting from transfection of in vivo tissues foUowing intravenous administration to mice of core complexes formed from commercially obtained cationic Upids with a sheU formed by inclusion of fusogenic surfactants (containing hydrophiUc PEG polymer with a low molecular weight - less than 2000 daltons) or steric surfactants (containing hydrophiUc PEG polymer with a high molecular weight - equal to or greater than 2000 daltons). Figure 8 shows increased expression by addition of a fusogenic peptide (K14-Fuso) derived from HA protein to polylysine core complexes. Figure 9 shows cleavage of hydrazone linkages at acidic pH. Figure 10A shows diagrams of some methods for incorporation of NLS into the payload nucleic acid and Figure 10B shows increased expression by linear DNA with PNA linked NLS bound to it versus linear DNA alone. Figure 11 shows dependence of particle size distribution on charge ratio of PEI/DNA and PEI-PEG5000/DNA complexes. Error bars represent the standard deviation of the particle size distribution. DNA (Salmon sperm) concentration: lOOμg/ml; Mol% PEG in the complex: 5.0 Figure 12 shows particle size stabiUty of a PEI-PEG5000/DNA complex containing lOOμg /ml salmon sperm DNA; Charge ratio 1 (+/-), 5 Mol% PEG in the complex: 5.0. Error bars represent the standard deviation of the particle size distribution Figure 13 shows the effect of PEG on the aggregation of PEI DNA complex in presence of serum. Particle size of PEI or PEI-PEG/DNA complexes containing varying mole% PEG before and after incubation with 10% serum. Samples incubated with serum at 37°C for 30 min were dialyzed extensively against a dialysis bag with a 1,000,000 MW cut off, before measuring the particle size. Error bars are standard deviations of the distribution. Figure 14 shows a schematic representation of the effect of PEG of different molecular weight, on protein mediated aggregation of positively charged PEI/DNA complexes. Figure 15A shows prolonged blood clearance of I 125 -DNA complexes with anchored PEG or PolyoxazoUne polymers in mice and Figure 15B shows reduced lung uptake of I 125 -DNA complexes with anchored PEG or PolyoxazoUne polymers in mice. Figure 16 shows the particle size of a PEI-ss-PEG5000/DNA complex. Bar 1 shows the average size of the particles made by complexing 250μg / ml DNA(Salmon Sperm) with PEI-ss-PEG5000 (PEI-ss-PEG5000 containing 11 mol% PEG) at 1: 1 charge ratio. Bar 2 shows a sample prepared in the same way except that PEI-ss-PEG5000 was treated with 10 mM DTT before complexation. Figure 17 shows the Zeta potential of PEI and PEI-ss-PEG5000 complexed with salmon sperm DNA at a charge ratio of 3 (+/-). Figure 18 shows particle size stabiUty of a cleavable PEI-ss- PEG5000/DNA complex containing 250 μg/ml Salmon sperm DNA; Charge ratio 1 (+/-),Mol% PEG in the complex: 10.0 Error bars represent the standard deviation of the particle size distribution Figure 19 shows luciferase activity of PEI/DNA and PEI-PEG and PEI-ss- PEG/DNA complexes. CeUs (BL6) were transfected in serum free medium for 3 hours with 0.5μg/weU (in 96 weU plate) of plasmid DNA complexed with PEI, PEI-PEG and PEI-ss-PEG at a charge ratio of 5. Luciferase activity was assayed 24 hours after transfection. Figure 20 shows luciferase activity of PEI/DNA and PEI-PEG/DNA complexes. CeUs (BL6) were transfected in serum free medium for 3 hours with 0.5μg/weU (in 96 weU plate) of plasmid DNA complexed with PEI or PEI-PEG at a charge ratio of 5. Luciferase activity was assayed 24 hours after transfection. Figure 21 shows the effect of PEG on the surface properties of the complex. Figure 22 shows the effect of PMOZ on the surface properties of the complex. The complexes were formulated at a charge-ratio of 4:1 and the zeta- potential measured in 10 mM saline. Figure 23 shows the effect of PMOZ on serum stabiUty (4:1 charge ratio complexes were prepared with varying amounts of PMOZ from 0 to 3.2 % (in steps of 0.8) and investigated for particle-size, before and after a 2h incubation in PBS containing 10% FBS at 37 OC). Figure 24 shows the effect of PMOZ on the expression by PEI core complexes. Figure 25 shows increased expression by addition of a peptide Ugand (K14RGD) to Upofectin core complexes. Figure 26 shows increased expression by addition of a peptide Ugand (SMT or Somatostatin) to core, complexes. Figure 27 A shows synthesis of linear PEI conjugated with a hindered disulfide to poIyethyloxazoUne (PEOZ) at one end and to a peptide Ugand, RGD, at the other end. Figure 27B shows synthesis of linear PEI conjugated with a hindered disulfide to poIyethyloxazoUne (PEOZ) at one end and to a peptide Ugand, SMT, at the other end Figure 28 shows increased ceUular uptake of Rh-oUgonucleotides complexed with PEI by addition of a peptide Ugand (RGD) to the distal end of PEG Conjugated PEI in HELA ceUs at charge ratio 6. Figure 29. Dose and charge ratio dependence on RA 1191 ceU deUvery and expression of luciferase plasmid by novel coUoid vectors. The luciferase expression level (pg/20,000 ceUs) is shown versus charge ratio of 4, 6, and 8 at a DNA dose of 0.1, 0.2, 0.4, 0.6, and 0.8 ug/20,000 ceUs. Figure 30. Ligand and charge ratio dependence on RA 1191 cefl deUvery and expression of luciferase plasmid by novel coUoid vectors. The luciferase expression level (pg/20,000 cells) is shown versus charge ratio of 0.4, 1, 2, 4, and 8. DETAILED DESCRIPTION Improved compositions and methods for deUvery of therapeutic nucleic acid are provided. The improved complexes comprise a stable gene deUvery vector having 1) an inner gene core complex and 2) an outer sheU moiety anchored to the inner core complex. The outer sheU moiety provides improved deUvery of the nucleic acid, target specificity, in vivo biological stabiUty, and coUoidal or physical stabiUty. The gene core complex contains a "payload" nucleic acid moiety, at least one core complex forming reagent, and advantageously contains additional functional units that facilitate ceU entry, nuclear targeting, and nuclear entry of the nucleic acid moiety foUowing entry into the target tissues and ceU. The core complex is one in which the nucleic acid is localized in a compartment largely free of "bulk water". Thus, the core complex is distinct from compositions such as Uposomes that entrap a relatively dilute solution of nucleic acid and where the nucleic acid "floats" around inside. The core complex does contain many water molecules that hydrate the nucleci acid, but there is not a large "entrapped" volume as is found in a Uposome. The gene core complex may include a fusogenic moiety as an integral part of the core complex, or the fusogenic moiety may comprise a separate layer or sheU of the vector. In this latter embodiment, the fusogenic moiety is anchored to the core complex, where the anchor comprises a linkage that is covalent, electrostatic, hydrophobic, or a combination of such forces. The nature of the anchoring linkage between the core complex and the fusogenic layer is such that the anchor may be separated from the nucleic acid once the vector enters the cytoplasm of the target ceU, thereby enhancing the biological activity of the payload nucleic acid. Likewise the core complex forming reagent is such that the nucleic acid is released and free to exert its biological activity in the nucleus or other compartment of the ceU where it exhibits its desired activity. The nucleic acid moiety payload contains one or more DNA or RNA molecules or chemical analogues. In one embodiment, this moiety encodes a therapeutic peptide, polypeptide, or protein. The payload also may directly or indirectly inhibit expression of an endogenous gene in the target tissue and ceU. For example, the payload may be a DNA molecule encoding a therapeutic RNA molecule or an antisense RNA, or may be an antisense oUgonucleotide, a ribozyme, a double stranded RNA that inhibits gene expression, a double stranded RNA/DNA hybrid, a viral genome, or other forms of nucleic acids. The functional unit that faciUtates nuclear targeting of the nucleic acid foUowing entry into the target tissue and ceϋ advantageously is a nuclear localization signal. The skiUed artisan wiU recognize, however, that other moieties may be used that enhance deUvery of the core complex to the nucleus of the target tissue and ceU. For example, the functional unit also may be a viral core peptide, polypeptide, or protein that enhances nuclear deUvery, or may be a nuclear membrane transport peptide also known as nuclear localization signal (NLS), or a steroid or steroid analogue moiety (see Ceppi et al, Program of the American Society of Gene Therapy meeting held at Washington D.C. on June 9-13, p217a, abs# 860 (1999)). In one embodiment, the gene deUvery vector has a steric barrier outer layer or sheU that provides modified surface characteristics for the complex, thereby diminishing the non-specific interactions that cause significant problems with conventional vector systems. The steric layer also has the advantage of suppressing the host immune response against the vector upon administration to the host. Advantageously, the outer layer protects the complex only prior to attachment and entry into the target tissue and ceU. In one embodiment, the outer layer then is shed, aUowing optimal biological activity of the payload nucleic acid. To achieve this goal, there is provided a steric coating on the surface of the complex, which minimizes interactions with serum components and non-target tissues and ceUs. The coating is anchored to the core complex in such a fashion that the steric coating is shed or cleaved from the complex at a point where ceUular interactions are beneficial. For example, one such point may occur after attachment of the complex to the target tissue and ceU, but prior to release of the core complex into the ceU cytoplasm. Another such point is within the extraceUular space of a target tissue. Yet another such point is after a predetermined time. Yet aother such point is within a target tissue that is exposed to an external signal or force such as heat or sonic energy. The sequence of events foUowing ceU entry ensures that deUvery of the payload is not impeded or otherwise inhibited by the steric layer. In another embodiment, the steric layer is designed and anchored such that it inhibits non-specific interactions but permits binding to target tissues and ceUs, ceH entry, and functional deUvery of the nucleic acid without cleavage of the anchor. The outer layer advantageously contains a targeting moiety that enhances the affinity of the interaction between the vector and the target tissue and ceU. A targeting moiety is said to enhance the affinity of the vector for a target ceU population when the presence of the targeting moiety provides an increase in the vector bound at the surface of target tissues and ceUs compared to non-target tissues and ceUs. Examples of targeting moieties include, but are not limited to proteins, peptides, lectins (carbohydrates), and smaU molecule Ugands, where each of the targeting moieties binds to a complementary molecule or structure on the ceU, such as a receptor molecule. Particular features of the invention are described in detaU below. The payload nucleic acid moiety The vectors of the present invention may be used to deUver essentiaUy any nucleic acid that is of therapeutic or diagnostic value. The nucleic acid may be a DNA, an RNA, a nucleic acid homolog, such as a triplex forming oUgonucleotide or peptide nucleic acid (PNA), or may be combinations of these. Suitable nucleic acids may include, but are not limited to, a recombinant plasmid, a repUcation- deficient plasmid, a mini-plasmid lacking bacterial sequences, a recombinant viral genome, a linear nucleic acid fragment encoding a therapeutic peptide or protein, a hybrid DNA/RNA double strand, double stranded RNA, an antisense DNA or chemical analogue, an antisense RNA or chemical analogue, a linear polynucleotide that is transcribed as an antisense RNA or a ribozyme, a ribozyme, and a viral genome. It wiU be understood that, as hereinafter used, the term "therapeutic protein" includes peptides, polypeptides, and proteins, unless otherwise indicated. When it is desired that the nucleic acid be integrated site-specificaUy into the genome of the host ceU, the nucleic acid sequence encoding the therapeutic protein may be flanked by stretches of sequence that are homologous to sequences in the host genome. These sequences facilitate integration into the host genome by the process of homologous recombination. Vectors for use in achieving homologous recombination are known in the art. When the nucleic acid is integrated in this site specific manner into the host genome, it is possible that expression of the nucleic acid can be under the functional control of endogenous expression control systems. More likely, however, it wiU be necessary to provide exogenous control elements that drive nucleic acid expression. Advantageously, the control elements wiU be ceU-specific, thereby enhancing the ceU-specific nature of the nucleic acid expression, though this is not essential. Suitable expression control elements, such as promoters and enhancer sequences (both ceU-specific and non-specific) are weU known in the art. See for example, Gazit et al, Can. Res. 59, 3100-3106 (1991), Walton etal, Anticancer Res, 18(3A): 1357-60 (1998); Clary et al, Surg-Oncol-Clin-N-Am. 7:565-74 (1998), Rossi et al/ Curr-Opin- Biotechnol 9: 451-6 (1998), Mffler et al, Hum-Gene-Ther. 8:803 (1997); Clackson, Curr. Opin. Chem. Biol 1:210-218 (1997). Suitable promoters include, but are not limited to, constitutive promotors such as EF-la, CMV, RSV, and SV40 large T antigen promoters, tissue specific promoters such as albumin, lung surfactant protein, tissue specific growth factor receptors, pathological tissue specific promoters such as alfa fetal protein tumor specific promoters, tumor specific proteins, inflammatory cascade proteins, necrosis response proteins, regulated promoters such as tetracycUne activated promoters and steroid receptor activated promoter or engineered promoters, and chromatin elements such as scaffold or matrix attachment regions (SAR or MAR), nucleosome elements, insulators, and enhancers. Suitable expression plasmids and mini-plasmids for use in the invention are weU known in the art (Prazeres et al, Trends-Biotechnol. 17:169 (1999); Kowalczyk et al, Cell-Mol-Life-Sci. 55:751 (1999); Mahfoudi, Gene Ther. Mol. Biol. 2:431 (1998). The plasmid may comprise an open reading frame sequence operationaUy coupled with promoter elements, intron sequences, and poly adenylation signal sequences. When the nucleic acid moiety is a plasmid, it advantageously wiU lack the nucleic acid elements that permit repUcation in bacteria. Thus, for example, the plasmid wiU lack a bacterial origin of repUcation. Most advantageously, the plasmid wiU be relatively free of sequences of bacterial origin. Methods for preparing such plasmids are weU known in the art (Prazeres supra). When the nucleic acid is of viral origin, suitable viral moieties include, but are not limited to, a recombinant adenoviral genome DNA (with and without the terminal protein), and a retroviral core derived from, for example, MLV or HTV env " particles. A recombinant alpha virus RNA for cytoplasmic expression and repUcation also may be used. Other viral genomes include herpes virus, SV-40, vaccinia virus, and adeno associated virus. Plasmid DNA or PCR generated DNA encoding a viral genome may be used. Other viral sources of nucleic acid may be used. When the nucleic acid is of synthetic origin, suitable moieties include, but are not limited to, PCR fragment DNA, DNA with terminal group chemical modifications or conjugation, antisense and ribozyme oUgonucleotides, linear RNA, linear RNA-DNA hybrids. Other sources of synthetic nucleic acid or nucleic acid analogues may be used. The complex forming reagent A complex-forming reagent suitable for use in the present invention must be capable of associating with the core nucleic acid in a manner that aUows assembly of the nucleic acid core complex. The complex forming reagent may be, for example, a Upid, a synthetic polymer, a natural polymer, a semi-synthetic polymer, a mixture of Upids, a mixture of polymers, a Upid and polymer combination, or a spermine analogue complex, though the skilled artisan wiU recognize that other reagents may be used. The complex forming reagent preferably has an affinity sufficient to enable formation of the complex under the conditions present for the preparation and sufficient to maintain the complex during storage and under conditions present foUowing administration but which is insufficient to maintain the complex under conditions in the cytoplasm or nucleus of the target ceU. Common examples of complex-forming reagents include cationic Upids and polymers, which permit spontaneous complexation with the core nucleic acid moiety under suitable mixing conditions, although neutral and negatively charged Upids and polymers may be used. Other examples include Upids and polymers in combination where some are cationic in nature and others in the combination are neutral or anionic in nature such that together a complex with a desired stabiUty balance is attained. In yet other examples, Upid and polymers may be used that have non-electrostatic interactions but that still enable complex formation with a desired stabiUty balance. For example, the desired stabiUty balance may be achieved through interactions with nucleic acid bases and back bone moieties like those of triplex oUgonucletide or "peptide nucleic acid" binding. In yet further examples conjugated Upids and polymers alone and in combinations may be used. Suitable cationic Upids for use in the invention are described, for example, in U.S. Patent Nos. 5,854,224 and 5,877,220, which are hereby incorporated by reference in their entirety. Suitable Upids typicaUy contain at least one hydrophobic moiety and one hydrophilic moiety. Other suitable Upids include a vesicle forming or vesicle compatible Upid, such as a phosphoUpid, a glycoUpid, a sterol, or a fatty acid. Included in this class are phosphohpids, such as phosphatidylcholine (PC), phosphatidylelhanolamine (PE), phosphatidic acid (PA), phosphatidylglycerol (PG), phosphatidyhnositol (PI), and glycoUpids, such as sphingomyelin (SM), where these compounds typicaUy contain two hydrocarbon chains that are characteristicaUy between about 14-22 carbon atoms in length, and may contain unsaturated carbon-carbon bonds. One class of preferred hydrophobic moieties includes hydrocarbon chains and sterols. Other classes of hydrophobic moieties include sphingosine, ceramide , and terpenes (poly-isoprenes) such as farnesol, Umonene, phytol, squalene, and retinol. Specific examples of Upids suitable for the invention include anionic, neutral, or zwitterionic Upids such as phosphatidylethanolamine, dioleoylphosphatidylethanolamine (DOPE), or cholesterol(Chol), cholesterol hemisuccinate (CHEMS), cholesterol sulfate, and diacylglycerol. Specific examples of cationic Upids include N-l-(2,3- dioleyloxy)propyl-N,N,N-trimethylammonium chloride (DOTMA), 1,2-bis (oleoyloxy)-3-(trimethylammonia) propane (DOTAP), 1, 2-dioleoyl-3- dimethylammonium propanediol (DODAP), dioctadecyldimethylammonium bromide (DODAB), dioctadecyldimethylammonium chloride (DODAC), dioctadecylamidoglycylspermine (DOGS), l,3-dioleoyloxy-2-(6- carboxyspermyl)propylamide (DOSPER), 2,3-dioleyIoxy-N-[2- (sperminecarboxaιnido)ethyl]-N,N-dimethyl -1-propanaminium trifluoroacetate (DOSPA or LipfectamineTM), hexadecyltrimethyl-ammonium bromide (CTAB), dimethyl-dioctadecylammonium bromide (DDAB), 1, 2-dimyristyloxyproρyl-3- dimethyl-hydroxy ethyl ammonium bromide (DMREE), dipataiitoylphosphatidylethanolamylspermine (DPPES), dioctylamineglycine- spermine (C8Gly-Sper), dihexadecylamine-spermine (C18-2-Sper), ammocholesterol-spermine (Sper-Chol), l-[2-(9(Z)-octadecenoyloxy)ethyl]-2- (8(Z)-heptadecenyl)-3-(2-hydι , oxyethyl)imidazolinium chloride (DOTIM), dimyristoyl-3-trimethylammoιιium-propane (DMTAP), 1.2-dimyristoyl-sn-glycero- 3-ethylphosphatidylcholine (EDMPC or DMEPC), lysylphosphatidylethanolamine (Lys-PE), cholestryl-4-aminoproprionate (AE-Chol), spermadine cholestryl carbamate (Genzyme-67), 2-(dipaUnitoyl-l,2-propandiol)-4-methyUmidazole (DPIm), 2-(dioleoyl-l,2-propandiol)-4-methyUmidazole (DOIm), 2-(cholestryl-l- propylamine carbamate)imidazole (Chlm), N-(4-pyridyl)-dipalmitoyl-l,2- propandiol-3-amine (DPAPy), 3β-[N-(N',N'- dimethylaminoethane)carbamoyl]cholesterol (DC-Chol), 3β-[N-(N',N',N- trimethylaminoethane)carbamoyl] cholesterol (TC-CHOL-gamma-d3), 1:1 mixture ofDOTMA and DOPE (Lipofectin7), , l,2-dioleoyl-sn-glycero-3-succinate, 1,2- dioleoyl-sn-glycero-3-succinyl-2-hydroxethyl disulfide ornithine conjugate (DOGSDSO) and l,2-dioleoyl-sn-glycero-3-succinyl-2-hydroxethyl hexyl orithine conjugate (DOGSHDO), N,N I ,N π ,N m -tetramethyl-N,N I ,N π ,N 111 - tetrapalmityolspermine (TM-TPS), 3-tetradecylamino-N-tert-butyl-N - tetradecylpropionamidine (vectamidine or diC14-amidine), N-[3-[2-(l,3- dioleoyloxy)propoxy-carbonyl]propyl]-N,N,N-trimethyla mmonium iodide (YKS- 220), and O,O'-Ditetradecanoyl-N-(alpha-trimethylammonioacetyl)diethan olamine chloride (DC-6-14) (see Lasic, Liposomes in Gene DeUvery, 1997, CRC Press, Boca Raton FL., Tang et l, Biochem. Biophys. Res. Comm. 242:141 (1998); Obika et l, Biol-Pharm-Bull. 22:187 (1999). Note that mixtures of a cationic Upid with a neutral Upid can be used, as weU as mixtures of cationic Upids plus neutral Upids including 3:1 wt/wt DOSPA:DOPE (Lipofectamine7), 1:1 wt/wt DOTMADOPE (Lipofectin7), 1:1 Mole/Mole DMRIE:Chol (DMRIE-CTM), 1:1.5 Mole Mole TM-TPS:DOPE (CellfectinTM), 1:2.5 wt/wt DDAB:DOPE (LipofectACE7), 1:1 wt/wt DOTAP:Chol, and many variants on these. Also note that such cationic Upid reagents, as weU as other cationic reagents that lack the hydrophobic moiety, can bind to the nucleic acid in such a manner that the nucleic acid is incorporated into low polarity environments including oils formed with triglyceride and/or sterols, emulsions formed with oUs combined with amphipathic stabiUzers such as fatty acids and lysophosphoUpids, microemulsions, an cubic phase Upid. One specific embodiment utilizes a multivalent cationic Upid such as DOGS in combination with with triglyceride and phosphatidylchoUne.-lysophosphatidylchoUne (2:1 or other ratio as needed to control particle size). Such compositions can be used to form core particles where anchoring occurs via addition of large hydrophobic moieties (having very low water solubiUty) such as octyldecyl (d 8 ) and longer hydrocarbon, phytanoyl hydrocarbon, or multiple moieties, or other such moieties. Another specific embodiment utilizes a multivalent cationic Upid such as DOGS in combination with hydrocarbon-flurocarbon "dowel" ( gFnHn), fluorocarbon "oU" (e.g. Cι 6 F 34 ), and phosphatidylchoUne:-lysophosphatidylchoUne (2:1 or other ratio as needed to control particle size). Such compositions can be used to form core particles where anchoring is by addition of fluorocarbon or hydrocarbon-fluorocarbon segments which can insert into the fluorcarbon "oU". A number of other cationic Upids are suitable for forming the core complex, and are described in the foUowing patents or patent appUcations: US 5,264,618, US 5,334,761, US 5,459,127, US 5,705,693, US 5,777,153, US 5,830,430, US 5,877,220, US 5,958,901, US 5,980,935, WO 09640725, WO 09640726, WO 09640963, WO 09703939, WO 09731934, WO 09834648, WO 9856423, WO 09934835 . For example, fourteen reagents described by patents or patent appUcations US 5,877,220, US 5,958,901, WO 96/40725, WO 96/40726, and WO 97/03939 are commerciaUy avaUable from Promega Biosciences [formerly JBL Scientific subsidiary of Genta Inc.] (San Louis Obisbo, CA) and their structures are shown in Figure 2.1-2.2. The hydrophobic portions range from sterol (cholesterol) to two or four hydrocarbon chains 17 or 18 carbons in length. The positively charged portions (hydrophiUc head groups) vary greatly but generaUy contain ionizable nitrogens (amines). The number of positive charges on each molecule varies from 1 to 13 and the molecular weight varies from 650 to 4212. Advantageously, the core complex can be prepared with GC-030 or GC- 034, either without any accessory components or with accessory components such as cholesterol or surfactants containing hydrophiUc polymer moieties. Alternatively, GC-029, GC-039, GC-016, GC-038 can be used, either alone or as mixtures with components such as Choi or surfactants. Numerous other Upid structures are described in US 5,877,220, US 5,958,901, WO 96/40725, WO 96/40726, and WO 97/03939 and may be used in the invention. The specific Upids having greatest utUity can be identified using four kinds of assays: 1) abiUty to form the nucleic acid into small, coUoidaUy stable, particles, 2) abiUty to enhance internalization of the nucleic acid into endosomes in ceUs in tissue culture, 3) abiUty to enhance cytoplasmic release of the nucleic acid in ceUs in tissue culture, and 4) abiUty to eUcit plasmid expression by in vivo tissues when administered locaUy or systemicaUy. Suitable cationic compounds further include substituted aminoethanols, having the general formula I where m is 3 or 4; Y signifies a group -(CH 2 )„-, in which n is 3 or 4, or may also signify a group -(CH 2 ) n -, in which n is an integer from 5 to 16, or may also signify a group -CH 2 -CH=CH-CH 2 -, if R 2 is a group -(CH 2 ) 3 -NR 4 R 5 and m is 3; R 2 is hydrogen or lower alkyl or may also signify a group -(CH 2 ) 3 -NR Rs if m is 3; R 3 is hydrogen or alkyl or may also signify a group -CH 2 -CH(-X -OH, if R 2 is a group -(CH 2 )3-NR4R5 and m is 3; X and X', independently of one another, signify hydrogen or alkyl; and the radicals R, Ri, t and R 5 , independently of one another, are hydrogen or lower alkyl; with the proviso that the radicals R, Ri, R 2 , R 3 and X cannot aU together signify hydrogen or methyl, if m is 3 and Y signifies a group -(CH 2 ) 3 -; and their salts. The general terms used hereinbefore and hereinafter have the foUowing significances in the context of the present apphcation: The prefix "lower" indicates a radical with up to and including 7, and in particular up to and including 3, carbon atoms. Lower alkyl is, for example, n-propyl, isopropyl, n-butyl, isobutyl, sec- butyl, tert.-butyl, n-pentyl, neopentyl, n-hexyl or n-heptyl. In one embodiment, lower alkyl is preferably ethyl and in particular methyl. In another embodiment, lower alkyl is fluorocarbon analogues of the hydrocarbon moieties. In yet another embodiment, lower alkyl is a combination of fluorocarbon and hydrocarbon. Alkyl is, for example, Cι-C 30 -aU yl, preferably -Ciβ-alkyl; alkyl is preferably linear alkyl, but may also be branched and is, for example, lower alkyl as defined above, n-octyl, n-nonyl, n-decyl, n-dodecyl, n-tetradecyl, n-hexadecyl or 2,7-dimethyloctyl. In another embodiment, alkyl is fluorocarbon analogues of the hydrocarbon moieties. In yet another embodiment, alkyl is a combination of fluorocarbon and hydrocarbon. Halogen signifies, for example, fluorine or iodine, especiaUy bromine and in particular chlorine. Salts of compounds according to the invention are primarily pharmaceuticaUy acceptable, non-toxic salts. For example, compounds of formula I that contain either 3 or 4 basic centres may form acid addition salts e.g. with inorganic acids, such as halogen acids like hydrochloric and hydroiodic acid, with sulfuric acid or phosphoric acid, or with appropriate organic carboxylic acids or sulfonic acids, e.g. acetic acid, trifluoroacetic acid, fumaric acid, oxaUc acid, methanesulfonic acid or p-toluenesulfonic acid, or e.g. with acidic amino acids, such as aspartic acid or glutamic acid. When associated with compounds of formula I, the term "salts" includes both monosalts and polysalts. For isolation or purification, pharmaceuticaUy unsuitable salts may also be used, e.g. picrates or perchlorates. For therapeutical usage, only the pharmaceuticaUy acceptable salts may be used, and for this reason these are preferred. Depending on the structural data, the compounds of the present invention may exist in the form of isomeric mixtures or as pure isomers. The compounds of formula I may be produced in known manner, whereby e.g. (a) a compound of formula π wherein m, Y, R, Ri, R 2 and R_ are defined as for formula I, in which the amino groups -NRRi, -NR 2 R 3 and optionaUy -N jRs in a radical R 2 = -(CH 2 ) 3 -NR 4 R 5 are optionaUy protected by appropriate protecting groups, is reacted with a compound of formula HI H 2 C— CH— X (III) O where X is defined as for formula I, and if necessary, the amino protecting group(s) are cleaved again, or (b) in order to produce compounds of formula I, in which m is 3, R 2 is a group -(CH^-N ^ and R 3 is a group -OHb-CHO-X^-OH, a compound of formula IV (IV) wherein Y, R, Ri, R» and R 5 are defined as for formula I, and in which the amino groups -NRRi and -N iRs are optionaUy protected by appropriate protecting groups, is reacted with a compound of formula III, in which X is defined as for formula I, and if necessary, the amino protecting group(s) are cleaved again, or (c) in order to produce compounds of formula I, wherein R, Ri, R 2 and R 3 signify hydrogen and Y is a group -(CH 2 ) n -, in which n is 3 or 4, a compound of formula V wherein m and X are defined as for formula I and n is 3 or 4, is reduced, or (d) in order to produce compounds of formula I, in which m is 3, R 2 signifies a group -(CH 2 ) 3 -NH 2 and R and Ri signify hydrogen, a compound of formula VI NC-(CH 2 ) 2 — N— Y— N— (CH 2 ) 2 -CN ( V |) CH 2 R 3 I CH-OH I X wherein X, Y and R 3 are defined as for formula I, is reduced; and/or if desired, an obtained compound of formula I may be converted into another compound of formula I, and/or, if desired, an obtained salt may be converted into the free compound or into another salt, and/or, if desired, an obtained free compound of formula I with salt-forming properties may be converted into a salt, and/or an obtained mixture of isomeric compounds of formula I may be separated into the individual isomers. In the more detailed description of processes a) to d) that foUows, the symbols m, n, X, X', Y, R and Rj to R 5 have the significances given for formula I, unless stated otherwise. Process (a): The amino groups -NRRi, -NR 2 R 3 and optionaUy -N t Rs are preferably protected by protecting groups. The way in which protecting groups act, e.g. amino protecting groups, the introduction thereof and cleavage thereof are known per se and are described e.g. in J.F.W. McOmie, "Protecting Groups in Organic Chemistry", Plenum Press, London and New York 1973, and T.W. Greene, "Protecting Groups in Organic Synthesis", WUey, New York 1984. Amino protecting groups that are especially suitable for polyamines such as spermine, spermidine, etc., are described e.g. in Ace. Chem. Res. 19:105 (1986) and Z. Nαturforsch. 41b, 122 (1986). Preferred monovalent amino protecting groups are ester groups, e.g. lower alkyl esters and in particular tert.-butoxycarbonyl (BOC), or phenyl lower alkyl esters, e.g. benzyloxycarbonyl (carbobenzoxy, Cbz), or acyl radicals, e.g, lower alkanoyl or halogen lower alkanoyl, such as especiaUy acetyl, chloroacetyl or trifluoroacetyl, or sulfonyl radicals, e.g. methylsulfonyl, phenylsulfonyl or toluene- 4-sulfonyl. Preferred bivalent amino protecting groups are bisacyl radicals, e.g. that of phthaUc acid (phthaloyl), which together with the nitrogen atom to be protected forms a phthalimido group. Cleavage of the amino protecting groups may take place e.g. hydrolyticaUy, perhaps in an acidic medium, e.g. with hydrochloric acid, or in an alkaline manner, e.g. with sodium hydroxide solution, or also by hydrogenation. Tert.-butoxycarbonyl is particularly preferred as the amino protecting group, and may be introduced e.g. by reacting the free amines with 2-(tert.- butoxycarbonyloxyimino)-2-(phenylacetonitrUe [tert.-butyl-0-C(=0)-0-N=C(- phenyl)-CN] or with di-(tert.-butyl)-dicarbonate. Cleavage of tert.-butoxycarbonyl is effected e.g. in an acidic medium, in particular with oxaUc acid or oxaUc acid dihydrate, hydrochloric acid or toluene-4-sulfonic acid or toluene-4-sulfonic acid monohydrate. Likewise preferred as the amino protecting group is benzyloxycarbonyl, which may be introduced by reacting the free amines with chloroformic acid benzyl ester. Cleavage of the benzyloxycarbonyl is preferably effected by hydrogenation, e.g. in the presence of paUadium on activated carbon. Also preferred as the amino protecting group is toluene-4-sulfonyl, which may be introduced by reacting the free amines with toluene-4-sulfochloride, optionaUy employing an auxiUary base such as triethylamine. Cleavage of toluene- 4-sulfonyl is preferably effected in an acidic medium, e.g. with concentrated sulfuric acid or 30% hydrobromic acid in glacial acetic acid and phenol, or also under alkaline conditions, e.g. with LiAlH Also preferred as the protecting group for terminal primary amino groups is phthaloyl, which is preferably introduced by a reaction with N-ethoxycarbonyl phthalimide. Cleavage of this protecting group takes place e.g. by reacting with hydrazine. The starting compounds of formulae II and m are known or may be produced in analogous manner to known compounds. The compounds of formula π in question are, in particular, spermidine, homospermidine, norspermidine, spermine, dehydrospermine or N,N -bis(3-an±ιoproρyl)-α,ω-alkylenediamine [see e.g. J. Med. Chem. 7, 710 (1964)], which exist in free form or protected form, and derivatives thereof. Compounds of formula in, wherein X signifies alkyl, may be present in racemic or opticaUy active form. If they are used as pure enantiomers in the reaction according to process (a) [or (b)], the corresponding opticaUy active compounds of formula I are obtained. Similarly, when reacted with compounds of formula VTI or VIII [see below processes (c) and (d)] opticaUy active compounds of formula V or VI are obtained. The reaction according to process (a) may take place in the presence of a solvent or also without solvents. Process (b): Process (b) corresponds to process (a), with the difference that here the group -CH 2 -CH(-X or -X OH is doubly introduced into the starting compounds of formula IV. Here also, the amino groups -NRRi and -NR1R 5 are preferably protected by protecting groups. The starting compounds of formula IV are known or may be produced in analogous manner to known compounds. The compounds of formula IV in question are, in particular, spermine, dehydrospermine or N,N -bis(3-aminopropyl)- α,co-alkylenediamine, which exist in free form or protected form, and derivatives thereof. Process (c): The reduction according to process (c) may be effected e.g. with hydrogen in the presence of suitable catalysts, e.g. Raney nickel. In addition, reduction may also be carried out with complex metal hydrides, such as LiAlH t or NaBHt. One preferred system for the reduction of compounds of formula V is H∑/Raney nickel in the presence of ethanol and ammonia or ethanol and sodium hydroxide. The starting compounds of formula V may be obtained e.g. by reacting a compound of formula VH NC-(CH 2 ) ra-I -NH-(CH 2 ) n . 1 -CN (VH) with a compound of formula III. The compounds of formula VII are in turn obtainable e.g. by reacting ammonia with compounds of formula Hal-(CH 2 ) 2 or3 -CN (Hal = halogen) [see CA. 63, 2642b (1963) or J. Med. Chem.15, 65 (1972)]. Unsymmetrical compounds of formula NH may be obtained e.g. according to A. 63, 2642b (1963) by reacting ΝC-(CH 2 ) 3 -ΝH 2 with acrylonitrile. Process (d): The reduction according to process (d) is carried out in the same way as that of process (c). The same reduction agents as in (c) are used. The starting compounds of formula VI may be obtained e.g. by reacting a compound of formula VH NC-(CH 2 ) 2 -NH-Y-N-(CH 2 ) 2 -CN (VIII) I R 3 with a compound of formula III. The compounds of formula VIII are in turn obtainable e.g. by reacting a diamine H 2 N-Y-NHR 3 with acrylonitrile. Compounds of formula I may be converted into other compounds of formula I in known manner. For example, compounds of formula I, wherein R, Rj and R 2 and R 3 (or R 4 and R 5 ) signify hydrogen, may be lower alkylated by reacting with aldehydes or ketones, e.g. formaldehyde, under reductive conditions, e.g. with hydrogen in the presence of paUadium on carbon, whereby for example compounds of formula I are obtained, wherein R, Ri and R 2 and R 3 (or R4 and R 5 ) signify lower alkyl. Furthermore, e.g. compounds of formula I, wherein m is 3, R 3 signifies hydrogen, R 2 is a group -(CH2) 3 -N ιRs and the amino groups -NRRi and -NR 4 R 5 are protected by protecting groups, may be reacted to form analogous compounds of formula I, wherein R 3 signifies alkyl, by reacting with alkylation agents, for example alkyl haUdes or dialkyl sulfates. Free compounds of formula I having salt-forming properties, which are obtainable according to this process, may be converted in known manner into the salts thereof. Since the free compounds of formula I contain basic groups, they may be converted into the acid addition salts thereof by treating with acids. Owing to the close relationship between the compounds of formula I in free form and in the form of salts, hereinbefore and hereinafter the free compounds or their salts are accordingly understood to mean also the corresponding salts or free compounds. The compounds, including their salts, may also be obtained in the form of their hydrates, or their crystals may include e.g. the solvent used for crystallization. Mixtures of isomers that are obtainable according to the invention can be separated in known manner into the individual isomers, racemates e.g. by forming salts with opticaUy pure salt-forming reagents and separating the diastereoisomeric mixture thus obtainable, for example by fractional crystallization. The above-mentioned reactions may be carried out under known reaction conditions, in the absence or normally in the presence of solvents or diluents, preferably those which are inert towards the reagents employed and which dissolve them, in the absence of presence of catalysts, condensation agents or neutralising agents, depending on the type of reaction and/or the reaction components at reduced, normal or elevated temperature, e.g. in a temperature range of ca. -70°C to 190°C, preferably -20°C to 150°C, e.g. at boiling point of the solvent employed, under atmospheric pressure or in a closed container, optionally under pressure and/or in an inert atmosphere, e.g. under a nitrogen atmosphere. In some instances, substituted aminoethanols appear to have two hydrophiUc polar heads connected by one hydrophobic body (Figure 3) and are referred to as bihead Upids. Since two hydrophilic heads at either side can face an aqueous solution, these compounds can form a monolayer in water instead of a bUayer formed by Upids with one head group (Figure 3). In another embodiment of the substituted aminoethanols, bihead Upid forms other than those described above can be used where the substituted aminoethanols have different electrostaticaUy charged polar heads, such as one positive and the other negative or neutral, and they can be used to form core complexes with a net excess of cationic charge in complexation with the nucleic acid but the complex formed has a neutral or negative surface charge. Such different polar bihead Upids can bind DNA with the positive head and form a monolayer coat around DNA with the negative or neutral head outside and thus a preferred negative or neutral surface charge. Further, the negative or neutral head provides a preferred moiety for anchoring other components of the vector. This is shown diagrammaticaUy in Figure 3.1-3.4. The two heads can have either the same or different charge states or forms that have substantiaUy different pK values such as a primary amine and an imidazole. Preparation of bihead Upids with heads that have different charged states have unique properties. Bihead Upids having one positive head and the other negative or neutral permit the positive head to bind to nuclear acid and the negative or neutral head to form an exterior surface of the complex facing the aqueous solution (Figure 3). Using the nucleic acid as a template for complex formation, the positive head binds and form a monolayer around it resulting in a monolayer Uposome/nucleic acid complex an with anionic or neutral surface. Such bihead Upids can highly encapsulate plasmid DNA, other nucleic acids, or any negatively charged substances giving a negative or neutral surface charge which avoids adverse biological interactions such as those leading to toxicity. The bihead Upids can be modified in other ways to give different properties of each head group. For example, one head can be conjugated with a steric polymer, with a targeting Ugand, with a fusogenic moiety, or with combinations of moieties such as a steric polymer with a targeting Ugand at the distal end. (Figure 3). The third kind of bihead Upids have both heads negative or neutral. These form useful monolayers of Upid around substances for control of pharmacokinetics and biodistribution much like Uposomes and emulsions are used. Suitable cationic compounds also include spermine analogues. The core complex formed with spermine analogues preferably comprises membrane disruption agents. In another embodiment, the core complex formed with spermine analogues comprises anionic agents to convey a negative surface charge to the core complex. Suitable polymers for use in the invention include polyethyleneimine (PEI), and advantageously PEI that is linear, polylysine, polyamidoamine (PAMAM dendrimer polymers, US Patent 5,661,025), linear polyamidoamine (HUl et al., Linear poly(amidoamine)s: physicochemical interactions with DNA and Biological Properties, in Vector Targeting Strategies for Therapeutic Gene DeUvery (Abstracts form Cold Spring Harbor Laboratory 1999 meeting), 1999, p 27), protamine sulfate, polybrine, chitosan (Leong et al. J ControUed Release 1998 Apr; 53(1-3): 183-93), polymethacrylate, polyamines (US Patent 5,880,161) and spermine analogues (US Patent 5,783,178), polymethylacrylate and its derivatives such as poly[2-(diethylamino)ethyl methacrylate] (PDEAMA) (Asayama et al, Proc. Int. Symp. Control. Rel. Bioact. Mater. 26, #6236 (1999) and Cherng etal EurJPharm Biopharm 47(3):215-24 (1999)) and ρoly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) (van de Wetering et al, J Controlled Release 53:145-53(1998)), poly(organo)phosphazenes (US Patent No. 5,914,231), which are hereby incorporated by reference in their entirety. Other polymers that may be used in the complex include polylysine, (poly(L), poly(D), and poly(D/L)), synthetic peptides containing amphipathic aminoacid sequences such as the "GALA" and "KALA" peptides (Wyman TB, Nicol F, Zelphati O, Scaria PV, Plank C, Szoka FC Jr, Biochemistry 1997, 36:3008-3017; Subbarao NK, Parente RA, Szoka FC Jr, Nadasdi L, Pongracz K, Biochemistry 1987 26:2964-2972) and forms containing non-natural aminoacids including D aminoacids and chemical analogues such as peptoids, imidazole-containing polymers, and fuUy synthetic polymers that bind and condense nucleic acid. Assays for polymers that exhibit such properties include measurements of plasmid DNA condensation into smaU particles using physical measurements such as DLS (dynamic Ught scattering) and electron microscopy. Other reagents useful in the invention for a core forming reagent include polymers with the general structure: where RI and R3 independently are a hydrocarbon or a hydrocarbon substituted with an amine, guanidinium, or imidazole moiety, and R2 is a lower alkyl group, or the general structure: where RI and R3 independently are a hydrocarbon or a hydrocarbon substituted with an amine, guanidinium, or imidazole moiety, and R2 and R4 independently are lower alkyl groups. Further reagents useful in the invention for a core forming reagent include those with a mixture of cationic and anionic groups, and in some instances an excess of negative charges, such that the complex formed has a net negative charge. Examples of such reagents are those having the general structure: where RI is a hydrocarbon or a hydrocarbon substituted with an amine, guanidinium, or imidazole moiety, R2 is a lower alkyl group, and R3 is a hydrocarbon or a hydrocarbon substituted with a carboxyl, hydroxyl, sulfate, or phosphate moiety; or reagents having the structure: where RI is a hydrocarbon or a hydrocarbon substituted with an amine, guanidinium, or imidazole moiety,R2 and R4 independently are lower alkyl groups, and R3 is a hydrocarbon or a hydrocarbon substituted with a carboxyl, hydroxyl, sulfate, or phosphate moiety. Nuclear targeting moiety A major barrier to efficient transcription and consequent expression of an exogenous nucleic acid moiety is the requirement that the nucleic acid enter the nucleus of the target ceU. Advantageously, when the intended biological activity of the nucleic acid payload is the nucleus, the nucleic acid of the invention is "nuclear targeted," that is, it contains one or more molecules that faciUtate entry of the nucleic acid through the nuclear membrane into the nucleus of the host ceU, a nuclear localization signal ("NLS"). Such nuclear targeting may be achieved by incorporating a nuclear membrane transport peptide, or nuclear localization signal ("NLS") peptide, or smaU molecule that provides the same NLS function, into the core complex. Suitable peptides are described in, for example, U.S. Patent Nos 5,795,587 and 5,670,347 and in patent apphcation WO 9858955, which are hereby incorporated by reference in their entirety, and in Aronsohn et al, J. Drug Targeting 1:163 (1997); Zanta etal, Proc. Nat'lAcad. Sci. USA 96:91-96 (1999); Ciolina et al, Targeting of Plasmid DNA to hnportin alpha by Chemical coupling with Nuclear Localization Signal Peptides, in Vector Targeting Strategies for Therapeutic Gene DeUvery (Abstracts from Cold Spring Harbor Laboratory 1999 meeting), 1999, p 20; Saphire et al, JBiol Chem; 273:29764 (1999). A nuclear targeting peptide may be a nuclear localization signal peptide or nuclear membrane transport peptide and it may be comprised of natural aminoacids or non-natural aminoacids including D aminoacids and chemical analogues such as peptoids. The NLS may be comprised of aminoacids or their analogues in a natural sequence or in reverse sequence. Another embodiment is comprised of a steroid receptor- binding NLS moiety that activates nuclear transport of the receptor from the cytoplasm, where this transport carries the nucleic acid with the receptor into the nucleus (Ceppi supra). In a further embodiment, the NLS is anchored onto the core complex in such a manner that the core complex is directed to the ceU nucleus where it permits entry of the nucleic acid into the nucleus. In one embodiment, incorporation of the NLS moiety into the vector occurs through association with the nucleic acid, and this association is retained within the cytoplasm. This minimizes loss of the NLS function due to dissociation with the nucleic acid and ensures that a high level of the nucleic acid is dehvered to the nucleus. Furthermore, the association with the nucleic acid does not inhibit the intended biological activity within the nucleus once the nucleic acid is deUvered. In yet another embodiment, the intended target, of the biological activity of the nucleic acid payload is the cytoplasm or an organeUe in the cytoplasm such as ribosomes, the golgi apparatus, or the endoplasmic reticulum. In this embodiment, a localization signal is included in the core complex or anchored to it so that it provides direction of the nucleic acid to the intended site where the nucleic acid exerts its activity. Signal peptides that can achieve such targeting are known in the art. Fusogenic moiety The fusogenic layer promotes fusion of the vector to the ceU membrane of the target ceU, faciUtating entry of the nucleic acid payload into the ceU. As described above, the fusogenic moiety may be incorporated directly into the core complex itself, or may be anchored to the core complex. In one embodiment, the fusogenic layer comprises a fusion-promoting element. Such elements interact with ceU membranes or endosome membranes in a manner that aUows transmembrane movement of large molecules or particles or that disrupts the membranes such that the aqueous phases that are separated by the membranes may freely mix. Examples of suitable fusogenic moieties include membrane surfactant peptides e.g. viral fusion proteins such as hemagglutinin (HA) of influenza virus, or peptides derived from toxins such as PE and ricin. Other examples include sequences that permit ceUular trafficking such as HIV TAT protein and antennapedia or those derived from numerous other species, or synthetic polymers that exhibit pH sensitive properties such as poly(ethylacryUc acid)(Lackey et al, Proc. Int. Symp. Control. Rel. Bioact. Mater. 1999, 26, #6245), N- isopropylacrylamide methacryUc acid copolymers (Meyer et al, FEBS Lett. 421:61 (1999)), or poly(amidoamine)s, (Richardson etal, Proc. Int. Symp. Control. Rel. Bioact. Mater. 1999, 26, #251), and Upidic agents that are released into the aqueous phase upon binding to the target ceU or endosome. Suitable membrane surfactant peptides include an influenza hemagglutinin or a viral fusogenic peptide such as the Moloney murine leukemia virus ("MoMuLV" or MLV) envelope (env) protein or vesicular stroma virus (VSV) G-protein. Advantageously, the membrane-proximal cytoplasmic domain of the MoMuLV env protein may be used. This domain is conserved among a variety viruses and contains a membrane-induced α-helix. Suitable viral fusogenic peptides for the instant invention include a fusion peptide from a viral envelope protein ectodomain, a membrane-destabilizing peptide of a viral envelope protein membrane-proximal domain, hydrophobic domain peptide segments of so caUed viral "fusion" proteins, and an amphiphiUc- region containing peptide. Suitable amphiphiUc-region containing peptides include: meUttin, the magainins, fusion segments from H. influenza hemagglutinin (HA) protein, HTV " segment I from the cytoplasmic tail of HTV1 gp41, and amphiphiUc segments from viral env membrane proteins including those from avian leukosis virus (ALV), bovine leukemia virus (BLV), equine infectious anemia (EIA), feline immunodeficiency vims (FTV), hepatitis virus, herpes simplex virus (HSV) glycoprotein H, human respiratory syncytia virus (hRSV), Mason-Pfizer monkey vims (MPMV), Rous sarcoma vims (RSV), parainfluenza vims (PINF), spleen necrosis virus (SNV), and vesicular stomatitis virus (VSV). Other suitable peptides include microbial and reptilian cytotoxic peptides. The specific peptides or other molecules having greatest utility can be identified using four kinds of assays: 1) abiUty to disrupt and induce leakage of aqueous markers from Uposomes composed of ceU membrane Upids or fragments of ceU membranes, 2) ability to induce fusion of Uposomes composed of ceU membrane Upids or fragments of ceU membranes, 3) abiUty to induce cytoplasmic release of particles added to ceUs in tissue culture, and 4) abiUty to enhance plasmid expression by particles in vivo tissues when administered locaUy or systemicaUy. The fusogenic moiety also may be comprised of a polymer, including peptides and synthetic polymers. In one embodiment, the peptide polymer comprises synthetic peptides containing amphipathic aminoacid sequences such as the "GALA" and "KALA" peptides (Wyman TB, Nicol F, Zelphati O, Scaria PV, Plank C, Szoka FC Jr, Biochemistry 1997, 36:3008-3017; Subbarao NK, Parente RA, Szoka FC Jr, Nadasdi L, Pongracz K, Biochemistry 198726:2964-2972 or Wyman supra, Subbarao supra ). Other peptides include non-natural aminoacids, including D aminoacids and chemical analogues such as peptoids, imidazole- containing polymers. Suitable polymers include molecules containing amino or imidazole moieties with intermittent carboxyUc acid functionaUties such as ones that form "salt-bridges," either internaUy or externaUy, including forms where the bridging is pH sensitive. Other polymers can be used including ones having disulfide bridges either internaUy or between polymers such that the disulfide bridges block fusogenicity and then bridges are cleaved within the tissue or intraceUular compartment so that the fusogenic properties are expressed at those desired sites. For example a polymer that forms weak electrostatic interactions with a positively charged fusogenic polymer that neutralizes the positive charge could be held in place with disulfide bridges between the two molecules and these disulfides cleaved within an endosome so that the two molecules dissociate releasing the positive charge and fusogenic activity. Another form of this type of fusogenic agent has the two properties localized onto different segments of the same molecule and thus the bridge is intramolecular so that its dissociation results in a structural change in the molecule. Yet another form of this type of fusogenic agent has a pH sensitive bridge. Other polymers can be used including polymers with amino or imidazole moieties with intermittent carboxyUc acid functionaUties such as ones that form "salt-bridges" either internaUy or externaUy including forms that the bridging is pH sensitive. In one embodiment, the polymer has a chemical structure as shown below. where RI is a hydrocarbon or a hydrocarbon substituted with an amine, guanidinium, or imidazole moiety, R2 is a lower alkyl group as defined above, and R3 is a hydrocarbon or a hydrocarbon substituted with a carboxyl, hydroxyl, sulfate, or phosphate moiety. In one embodiment the polymer is designed to bear an excess positive charge such as when RI contains an amine or guanidinium and R3 contains a carboxyl with X about equal with Y or greater than Y or when RI contains an imidazole and R3 contains a carboxyl with X in excess ofY. In another embodiment the polymer is designed to bear an excess negative charge so typicaUy Y is in excess of X. In yet another embodiment the polymer is designed to have a net charge near neutraUty and the X to Y ratio is adjusted accordingly. In another embodiment, the polymer has a chemical structure as described below. where RI is a hydrocarbon or a hydrocarbon substituted with an amine, guanidinium, or imidazole moiety, R2 and R4 independently are lower alkyl groups as defined above, and R3 is a hydrocarbon or a hydrocarbon substituted with a carboxyl, hydroxyl, sulfate, or phosphate moiety. In one embodiment the polymer is designed to bear an excess positive charge such as when RI contains an amine or guanidinium and R3 contains a carboxyl with X about equal with Y or greater than Y or when RI contains an imidazole and R3 contains a carboxyl with X in excess ofY. In another embodiment the polymer is designed to bear an excess negative charge so typicaUy Y is in excess of X. In yet another embodiment the polymer is designed to have a net charge near neutrahty and the X to Y ratio is adjusted accordingly. The fusogenic moiety also may comprise a membrane surfactant polymer- Upid conjugate. Suitable conjugates include Thesit™, Brij 58™, Brij 78™, Tween 80™, Tween 20™, d 2 E 8 , C 14 E 8 , C 16 E 8 (C„E n = hydrocarbon polyethylene glycol) ether where C represents hydrocarbon of carbon length N and E represents poly(ethylene glycol) of degree of polymerization N), Chol-PEG 900, analogues containing polyoxazoUne or other hydrophiUc polymers substituted for the PEG, and analogues having fluorocarbons substituted for the hydrocarbon. Advantageously, the polymer wiU be either biodegradable or of sufficiently smaU molecular weight that it can be excreted without metaboUsm. The skiUed artisan wiU recognize that other fusogenic moieties also may be used without departing from the spirit of the invention. Assembly of the core complex The core complex advantageously will be self-assembling when mixing of the components occurs under appropriate conditions. Suitable conditions for preparing the core complex generally permit the charged component that is present in charge molar excess at the end of the mixing to be in excess throughout the mixing. For example, if the final preparation is a net negative charge excess then the cationic agent is mixed into the anionic agent so that the complexes formed never have a net excess of cationic agent. Another suitable condition for preparing the core complex utilizes a continuous mixing process including mixing of the core components in a static mixer. A static mixer produces turbulent flow and preferably low shear force mixing in two or more fluid streams flowing into and through a stationary device resulting in a mixed fluid that exits the device. For core complexes low shear force mixing is expeciaUy important when the nucleic acid is fragfle to shear. SpecificaUy, aqueous solutions of nucleic acid and core complex-forming moieties (such as a cationic Upid) are fed together into a static mixer (avaUable from, for example, American Scientific Instruments, Richmond, CA), where the streams are spUt into inner and outer heUcal streams that intersect at several different points causing turbulence and thereby promoting mixing. The use of commerciaUy avaUable static mixers ensures that the results obtained are operator-independent, and are scalable, reproducible, and controUable. The core complex particles so produced are homogeneous, stable, and can be sterile filtered. When the core complex is intended to contain a nuclear targeting moiety and/or a fusogenic moiety, these components may be added directly into the streams entering the static mixer so that they are automaticaUy incorporated into the core complex as it is formed. The component streams intersect in the mixer, whereby shearing and mixing of the DNA and polymer are induced, whereby particles of a complex of DNA and polymer are formed. The resulting preparations may be tested for mean particle size in nanometers and distribution through dynamic Ught scattering using, for example, a Coulter N4 Plus Submicron Particle Sizer (Coulter Corporation, Miami, Florida). Mean particle sizes and standard deviaitons can be determined by the unimodal and Size Distribution Processing (SDP), or "intensity" methods. In the above methods, a laser is directed through a preparation of the particles. Dynamic Ught scattering is measured as a result of the Brownian motion of the particles. The dynamic Ught scattering which is measured then is correlated to particle size. In the unimodal method, the size distribution is determined by placing the sizes of the particles on a Gaussian curve. In the SDP method, size distribution is determined by a FORTRAN program caUed CONTIN. Such methods also are described further in the Coulter N4 Plus Submicron Particle Sizer Reference Manual (November 1995). When the fusogenic moiety is not incorporated directly into the core moiety, it typicaUy is present as a sheU surrounding or enveloping the core complex. In this situation the fusogenic sheU is anchored to the core complex either electrostaticaUy, covalently, or via hydrophobic interaction, or by a combination of such forces. When the fusogenic moiety is electrostaticaUy anchored it interacts with charged groups of either the nucleic acid, or the complex forming agent, or both, through charge-charge interactions. Presence of multivalent electrostatic interactions allows binding stabiUty but also accomodates appropriate release within the target tissue and ceU. One specific form is a fusogenic peptide sequence coupled to a cationic peptide sequence where the cationic sequence insures that the peptide either incorporates into the core complex at the time of its formation or it incorporates onto the surface of a negatively charged core complex after its formation. One example of this type of moiety and its incorporation is the inclusion of a peptide comprised of a linear sequence of 14 lysine residues coupled to a short hydrophobic amino acid sequence from the fusion domain of H. influenze HA protein shown in Example 46. Other examples include use of synthetic cationic polymers such as PEI coupled with fusogenic segment polymers such as poly[2-(diethylamino)ethyl methacrylate] (PDEAMA) or N-isopropylacrylamide methacryUc acid copolymers. When the fusogenic moiety is anchored with hydrophobic interactions it contains a segment or moiety that associates with the core complex in such a manner that the association reduces contact with the aqueous solution and thereby reduces the energy of the anchored complex. In one embodiment, the anchor hydrophobic interactions are between hydrocarbon moieties of the fusogenic moiety and hydrocarbon moieties of the core complex. One specific form utilizing hydrophobic anchoring are diacyl Upids conjugated with a fusogenic moiety where the Upid portion interacts strongly with core complexes formed with cationic Upids. In another embodiment, the anchor hydrophobic interactions are between fluorocarbon moieties of the fusogenic moiety and fluorocarbon moieties of the core complex. Other forms of hydrophobic interaction forces that enable suitable anchoring are possible. When the fusogenic moiety is covalently linked to the core complex, covalent coupling occurs: (1) to complex forming reagents; (2) to a compound that becomes incorporated in the complex at its time of formation; (3) to the surface of a preformed complex; or (4) to a compound that associates with the surface of a preformed complex. In one embodiment the linkage preferably is cleaved upon entry of the vector into a target tissue or ceU. This cleavage may be achieved by anchoring the fusogenic layer via a cleavable linkage. Examples include: (1) an acid labUe linkage, such as a Schiffs base or a hydrazone or vinyl ether; (2) a reducible linkage such as a disulfide linkage; or (3) one of the linkers described below for use in attachment of the outer steric layer. Acid labUe linkers are cleaved in the acid conditions that prevail in targeted tissues or in intraceUular compartment such as the endosome structure into which the vector first wiU be transported upon ceUular uptake by most mechanisms. In one embodiment, the fusogenic layer has a hydrophobic nature such that it forms a layer in which water is largely excluded. When such a layer is formed on the core complex, it can be generated by numerous possible methods such as addition along with the complex forming agent where the layer forms by self assembly or by addition in a second step once the core complex has been formed. In one embodiment, the layer is formed at the same time as the core complex as iUustrated in Examples 38-43. In another embodiment, the layer is formed by a second mixing step where a core complex is formed in the first mixing step and then the layer is added by a subsequent mixing step between the core complex and the reagent that forms the layer on the pre-existing complex. In one embodiment of the invention, the use of core complexes which are negative or neutral in surface charge is preferred. In this embodiment, the outer sheU conveys target tissue and ceU binding and uptake properties in contrast to the cationic complex-anionic ceU electrostatic binding mechanism that is thought to provide binding and uptake by positively-charged core complexes. By aUowing use of neutral or negative surface charge core complexes, numerous benefits can be realized. The reduction or elimination of electrostatic interactions with positive surface charge vector coUoids can reduce or eliminate non-specific interactions leading to phagocytic clearance, to toxicity in non-target tissues and organs, and to ceU toxicity in target tissues and organs. It is to be understood that the present invention is not to be limited to the treatment of any particular disease or disorder. The particles which include a nucleic acid sequence encoding a therapeutic agent, may be administered to an animal in vivo as part of an animal model for the study of the effectiveness of a gene therapy treatment. The particles may be administered in varying doses to different animals of the same species, whereby the particles wiU transfect ceUs in the animal. The animals then are evaluated for the expression of the desired therapeutic agent in vivo in the animal. From the data obtained from such evaluations, one may determine the amount of particles to be administered to a human patient. In another embodiment, the particles may be employed to transfect ceUs in vitro. The cells, which now include a nucleic acid sequence encoding a therapeutic agent, may be administered to a host such as hereinabove described, in order to express the therapeutic agent and/or provide a therapeutic effect in the host. CeUs which may be transfected and methods of administration may be selected from those hereinabove described. The particles of the present invention also may be employed to transfect ceUs of an organ in vitro. The organ, which now includes ceUs which include a nucleic acid sequence encoding a therapeutic agent, may be transplanted into an animal, whereby the transplanted organ expresses the therapeutic agent in the animal and/or provide a therapeutic effect in the animal. The animal may be a mammal, including human and non-human primates. The particles of the present invention also may be employed in the in vitro transfection of ceUs, which are contained in a ceU culture containing a mixture of ceUs. Upon transduction of the ceUs in vitro, the ceUs produce the therapeutic agent or protein in vitro. The therapeutic agent or protein then may be obtained from the ceU culture by means known to those skilled in the art. The particles also may be employed for the transfection of ceUs in vitro in order to study the mechanism of the genetic engineering of ceUs in vitro. Outer shell moiety It is known that polyethylene glycol (PEG), an uncharged hydrophiUc polymer, can provide a steric barrier for oUgonucleotide/cationic Upid complexes (Meyer et al, J. Biol. Chem. 273:15621 (1998); Scaria supra, PhiUps supra). The present invention improves upon conventional uses of steric barriers by providing a barrier that is anchored to the core complex. The barrier also may optionaUy contain targeting moieties that enhance binding of the vectors to the target tissue and ceU and also that may optionally be anchored via an attachment that is cleaved at target tissues or in intraceUular compartments into which the vector typicaUy first wiU be transported upon ceUular uptake. In embodiments where the core complex is anchored to a fusogenic sheU moiety, the outer steric layer is in turn anchored, as described below, to the core complex, the fusogenic sheU, or to both. In embodiments where the fusogenic moiety is incorporated directly into the core complex, the steric layer is anchored directly to the core complex. The outer steric layer preferably comprises a hydrophiUc, biodegradable polymer. If the polymer is not biodegradable then a relatively low molecular weight (<30 kDaltons) polymer is used. The polymer may also exhibit solubiUty in both polar and non-polar solvents. Suitable polymers include PEG (of various molecular weights), polyvinylpyrroUdone (PVP), and polyvinylalcohol, polyvinylmethylether, polyhydroxypropyl methacrylate, polyhydroxypropylmethacrylamide, polyhydroxyethyl acrylate, polymethacrylamide, polydimethylacrylamide, polylactic acid, polyglycoUc acid, polymethyloxazoline, poIyethyloxazoUne, polyhydroxyethyloxazoline, polyhydroxypropyloxazoUne, or polyaspartamide which are weU known in the art (US Patent No. 5,631,018). Other suitable polymers include those that wiU form a steric barrier on coUoidal particulates of at least 5 nm "thickness" or greater as determined by reduction in zeta potential (Woodle et al., Biophys. J. 61:902 (1992)) or other such assays. Further suitable polymers include those that contain branches. In one embodiment, the hydroxyl functions of a glucose moiety are used to conjugate multiple steric polymers, one of which is anchored to the core complex. In another embodiment, the amine functions of a lysine are used to conjugate two steric polymers and the carboxyl function is used with a steric polymer linker to conjugate onto the core complex. When PEG is used as the hydrophilic polymer conjugate, the PEG preferably has a molecular weight of between about 1,000 to about 50,000 daltons. TypicaUy, the PEG chain has a molecular weight of about 2,000 to about 20,000 daltons. Mixtures of molecular weight can also be used which can have particular advantages for combining steric properties best found in a large polymer, e.g. blocking ceUular interactions, with those best found in a smaU polymer, e.g. blocking smaU protein interactions. When used without a Ugand at the end distal to coupling, the PEG contains an unreactive methoxy group at its free end, and is coupled to the Unking segment through a reactive chemical group. Methods of preparing such Unking is weU known in the art as summarized in a recent text book on conjugation (Greg T. Hermanson, Biconjugate techniques, Academic Press Inc., San Diego, 1996).. Alternative polymers include, but are not limited to, polylactic acid, polyglycoUc acid, polyvinylpyrroUdone, polymethacrylamide, poIyethyloxazoUne, polymethyloxazoUne, polydimethylacrylamide, polyvinylmethylether, polyhydroxypropyl methacrylate, polyhydroxypropyUnethacrylamide, polyhydroxyethyl acrylate, polyhydroxyethyloxazoline, polyhydroxypropyloxazoUne, or polyaspartamide. As described above for PEG, when used without a Ugand at the end distal to coupling, each of these hydrophilic polymers preferably has an unreactive group or a hydroxyl at its free end, and is coupled to the Unking segment through a reactive chemical group. Anchoring is provided either by electrostatic, covalent, or hydrophobic interaction, or by a combination of such forces. When the outer sheU is electrostaticaUy anchored it interacts with charged groups located on the nucleic acid or on the complex forming agent, or both through charge-charge interations. The presence of multivalent electrostatic interactions not aUows binding stabiUty but also accomodates appropriate release within the target tissue and ceU. When the outer sheU is anchored with hydrophobic interactions it contains a segment or moiety that associates with the core complex in such a manner that the association reduces contact with the aqueous solution and thereby reduces the energy of the anchored complex. In one embodiment, the anchor hydrophobic interactions are between hydrocarbon moieties of the outer sheU and hydrocarbon moieties of the core complex. In another embodiment, the anchor hydrophobic interactions are between fluorocarbon moieties of the outer sheU and fluorocarbon moieties of the core complex. Other forms of hydrophobic interaction forces that enable suitable anchoring are possible. In one embodiment, such hydrophobic achors are comprised of peptide sequences that associate and intercalate with Upid bUayers such as membrane anchor domains including sequences from membrane proteins such as cytochrome b5 (Thr-Asn-Trp-Val-Ile-Pro-Ala-Ile-Ser-Ala-Val-Val-Val- Ala-Leu-Met-Tyr-Arg-Ile-Tyr-Thr-Ala) or membrane spanning sequences. When the outer sheU is covalently linked to the core complex, covalent coupling is provided to complex forming reagents, or alternatively through covalent coupling to a compound that becomes incorporated in the complex at its time of formation, or alternatively through covalent coupling to the surface of a preformed complex, or alternatively through covalent coupling to a compound that associates with the surface of a preformed complex. In one embodiment the linkage preferably is cleaved upon entry of the vector into a target tissue or ceU. This cleavage may be achieved by anchoring the outer sheU via cleavable linkage such as an acid labUe linkage, such as a Schiff s base or a hydrazone, vinyl ether, or as a reducible linkage such as a disulfide linkage, or one of the linkers described below for use in attachment of the outer steric layer. Acid labile linkers are cleaved in the acid conditions that prevaU in targeted tissues or in intraceUular compartment such as the endosome structure into which the vector first wiU be transported upon ceUular uptake by most mechanisms. In one embodiment, the fusogenic layer has a hydrophobic nature such that it forms a layer in which water is largely excluded. When such a layer is formed on the core complex, it can be generated by numerous possible methods such as addition along with the complex forming agent and the layer forms by self assembly or by addition in a second step once the core complex has been formed. In another embodiment, the polymer is used with a Ugand. The Ugand is comprised of a molecule that provides for binding to target tissues and ceUs such that the nucleic acid payload exerts its biological activity. Suitable Ugands include proteins, peptides, and their chemical analogues, carbohydrates, and smaU molecules. In one embodiment, the Ugand is attached to the core complex in a manner simUar to that of the fusogenic moiety or of the steric polymer. In another embodiment, the Ugand is attached to the steric polymer at the end distal to its coupling to the core complex. Suitable attachment of the Ugand include stable covalent linkage, cleavable linkage, and non-covalent attachment that retains the Ugand untU the desired binding event can occur. The targeting moiety To enhance binding of the vector to target tissue or ceUs, the outer sheU layer advantageously wUl include at least one targeting moiety that permits highly specific interaction of the vector with the target tissue or ceU. More specificaUy, in one embodiment, the vector preferably wiU include an unshielded Ugand attached to the outer layer, effective for Ugand-specific binding to a receptor molecule on a target tissue and ceU surface (Woodle et al, SmaU molecule Ugands for targeting long circulating Uposomes, in Long Circulating Liposomes: Old drugs, new therapeutics, Woodle and Storm. eds., Springer, 1998, p 287-295). In another embodiment, the vector preferably wiU include a shielded Ugand attached within the outer layer or at the surface of the core complex where the outer layer is lost under defined tissue or target conditions, revealing the Ugand so that it can bind to the target tissue or ceU. The vector may include two or more targeting moieties, depending on the ceU type that is to be targeted. Use of multiple (two or more) targeting moieties can provide additional selectivity in ceU targeting, and also can contribute to higher affinity and/or avidity of binding of the vector to the target ceU. When more than one targeting moiety is present on the vector, the relative molar ratio of the targeting moieties may be varied to provide optimal targeting efficiency. Methods for optimizing ceU binding and selectivity in this fashion are known in the art. The skilled artisan also wiU recognize that assays for measuring ceU selectivity and affinity and efficiency of binding are known in the art and can be used to optimize the nature and quantity of the targeting Ugand(s). Suitable Ugands include, but are not limited to: vascular endotheUal ceU growth factor for targeting endotheUal ceUs: FGF2 for targeting vascular lesions and tumors; somatostatin peptides for targeting tumors; transferrin for targeting tumors; melanotropin (alpha MSH) peptides for tumor targeting; ApoE and peptides for LDL receptor targeting; von WiUebrand's Factor and peptides for targeting exposed coUagend; Adenoviral fiber protein and peptides for targeting Coxsackie-adeno viral receptor (CAR) expressing ceUs; PD1 and peptides for targeting Neuropilin 1 ; EGF and peptides for targeting EGF receptor expressing ceUs; and RGD peptides for targeting integrin expressing ceUs. Other examples include (i) folate, where the composition is intended for treating tumor ceUs having ceU-surface folate receptors, (ii) pyridoxyl, where the composition is intended for treating virus-infected CD4+ lymphocytes, or (in) sialyl-Lewis 0 , where the composition is intended for treating a region of inflammation. Other peptide Ugands may be identified using methods such as phage display (F. BartoU et al, Isolation of peptide Ugands for tissue-specific ceU surface receptors, in Vector Targeting Strategies for Therapeutic Gene DeUvery (Abstracts form Cold Spring Harbor Laboratory 1999 meeting), 1999, p4) and microbial display (Georgiou et al, Ultra-High Affinity Antibodies from Libraries Displayed on the Surface of Microorganisms and Screened by FACS, in Vector Targeting Strategies for Therapeutic Gene DeUvery (Abstracts form Cold Spring Harbor Laboratory 1999 meeting), 1999, p 3.). Ligands identified in this manner are suitable for use in the present invention. In a particular embodiment, the targeting Ugand may be somatostatin or a somatostatin analog. Somatostatin has the sequence AGCLNFFWKTFTSC, and contains a disulfide bridge between the cysteine residues. Many somatostatin analogs that bind to the somatostatin receptor are known in the art and are suitable for use in the present invention. See for example, US Patent No. 5,776,894, which is incorporated herein by reference in its entirety. Particular somatostatin analogs that are useful in the present invention are analogs having the general structure F * CY-(DW)KTCT, where DW is D-tryptophan and F * indicates that the phenylalanine residue may have either the D- or L- absolute configuration. As in somatostatin itself, these compounds are cycUc due to a disulfide bond between the cysteine residues. Advantageously, these analogs may be derivatized at the free amino group of the phenylalanine residue, for example with a polycationic moiety such as a chain of lysine residues. The skilled artisan wiU recognize that other somatostatin analogs that are known in the art may advantageously be used in the invention. Furthermore, methods have been developed to create novel peptide sequences that eUcit strong and selective binding for target tissues and ceUs such as "DNA Shuffling" (W.P.C. Stremmer, Directed Evolution of Enzymes and Pathways by DNA Shuffling, in Vector Targeting Strategies for Therapeutic Gene DeUvery (Abstracts form Cold Spring Harbor Laboratory 1999 meeting), 1999, p.5.) and these novel sequence peptides are suitable Ugands for the invention. Other chemical forms for Ugands are suitable for the invention such as natural carbohydrates which exist in numerous forms and are a commonly used Ugand by ceUs (Kraling et al., Am. J. Path. 150: 1307 (1997) as weU as novel chemical species, some of which may be analogues of natural Ugands such as D-amino acids and peptidomimetics and others which are identifed through medicinal chemistry techniques such as combinatorial chemistry (P.D. Kassner et al., Ligand Identification via Expression (LIVEO): Direct selection of Targeting Ligands from Combinatorial Libraries, in Vector Targeting Strategies for Therapeutic Gene DeUvery (Abstracts form Cold Spring Harbor Laboratory 1999 meeting), 1999, p8.). The targeting layer is composed of Ugands that provide the desired tissue and ceU specific binding exposed at the surface of the complex, either that of the core complex, the surface of the fusogenic layer, or the surface of the protective, steric, layer. The Ugands are covalently attached to the coUoid such that their exposure is adequate for tissue and ceU binding. Anchoring is provided by covalent coupling to complex forming reagents, or alternatively through covalent coupling to a compound that becomes incorporated in the complex at its time of formation, or alternatively through covalent coupling to the surface of a preformed complex, or alternatively through covalent coupling to a compound that associates with the surface of a preformed complex. For example a peptide Ugand can be covalently coupled to a steric polymer such as polyoxazoUne which is covalently coupled at its distal end to a polycation such as linear PEI. The PEI wiU form a layered coUoid complex with the nucleic acid payload forming a surface sheU of steric polymer with peptide Ugands exposed on the surface. Alternatively, this same peptide conjugate can be combined with a polycation such as linear PEI or a cationic Upid in an aqueous solution that is then used to condense a nucleic acid payload into a layered coUoid with the Ugand exposed above a surface steric polymer sheU. Alternatively this same peptide conjugate can be complexed with a negatively charged complex of nucleic acid payload at least partiaUy condensed with a polycation or cationic Upid resulting in a layered coUoid with the Ugand exposed above a surface steric polymer sheU. SimUarly, a peptide Ugand can be covalently coupled to a steric polymer such as polyoxazoUne which is covalently coupled at its distal end with a Upid and this conjugate used as above with polycations and/or cationic Upids and/or neutral or negative Upid coUoids containing a nucleic acid payload. The number of targeting molecules present on the outer layer wiU vary, depending on factors such as the avidity of the Ugand-receptor interaction, the relative abundance of the receptor on the target tissue and ceU surface, and the relative abundance of the target tissue and ceU. Nevertheless, 25-100 targeting molecules on the surface of each vector usuaUy provides suitable enhancement of ceU targeting. The presence of the targeting moiety leads to the desired enhancement of binding to target tissue and ceUs. An appropriate assay for such binding may be ELISA plate assays, ceU culmre expression assays, or any other binding assays. One example of binding is shown in Example 48 and Figure 25 and 26. Anchoring of the outer shell moiety As described above, the outer steric layer of the outer sheU moiety is anchored to the inner fusogenic layer, to the core complex, or both. This anchoring may be either electrostaticaUy, covalently, or with hydrophobic interaction, or a combination of such forces. When the outer sheU is electrostaticaUy anchored it interacts with charged groups of either the nucleic acid, or the complex forming agent, or both, through charge-charge interactions. Presence of multivalent electrostatic interactions aUows binding stability but also accomodates appropriate release within the target tissue and ceU. When the outer sheU is anchored with hydrophobic interactions it contains a segment or moiety that associates with the core complex in such a manner that the association reduces contact with the aqueous solution and thereby reduces the energy of the anchored complex. In one embodiment, such achors are comprised of peptide sequences that associate and intercalate with Upid bUayers such as membrane anchor domains including sequences from membrane proteins such as cytochrome b5 (Thr-Asn- Trp-Val-Ile-Pro-Ala-He-Ser-Ala-Val-Val-Val-Ala-Leu-Met-Tyr-Arg-Ile-Tyr-Thr- Ala) or membrane spanning sequences. In one embodiment, the anchor hydrophobic interactions are between hydrocarbon moieties of the outer sheU and hydrocarbon moieties of the core complex. In another embodiment, the anchor hydrophobic interactions are between fluorocarbon moieties of the outer sheU and fluorocarbon moieties of the core complex. Other forms of hydrophobic interaction forces that enable suitable anchoring are possible. When the outer sheU is covalently linked to the core complex, covalent coupling occurs: (1) to complex forming reagents; (2) to a compound that becomes incorporated in the complex at its time of formation; (3) to the surface of a preformed complex; or (4) to a compound that associates with the surface of a preformed complex. When the outer sheU is anchored to the fusogenic layer via a covalent bond, the linkage may be stable, and in this embodiment, the outer layer will be shed along with the fusogenic layer upon ceU entry. One example of a stable linkage is a carbamate linkage. In another embodiment, the linkage preferably is cleaved upon entry of the vector into a target tissue or ceU. In one embodiment, the fusogenic layer has a hydrophobic nature such that it forms a layer in which water is largely excluded. When such a layer is formed on the core complex, it can be generated by numerous possible methods such as addition along with the complex forming agent where the layer forms by self assembly or by addition in a second step once the core complex has been formed. When the outer layer is anchored directly to the core complex, it preferably is cleavable under the conditions prevailing in the endosome. This cleavage may be achieved by anchoring the outer sheU via cleavable linkage such as an acid labUe linkage or as a reducible linkage such as a disulfide linkage. Acid labile linkers are cleaved in the acid conditions that prevaύ in targeted tissues or in intraceUular compartment such as the endosome structure into which the vector typicaUy is first transported upon ceUular uptake. Suitable cleavable linkages include a disulfide bond, and an acid labUe linkage such as a Schif s base, or a hydrazone, or a vinyl ether. For example, the core complex may contain free amine groups, and the steric layer may contain pendent aldehyde groups. Mixing of the core complex with the steric layer component wiU result in formation of a Schiff s base between the core complex and the steric layer. Alternatively, for example, a disulfide bond can be formed between free sulfhydryl groups present on the core complex and the steric layer, respectively. In a preferred embodiment, the cleavable linkage layer comprises a pH sensitive covalent bond. More preferably, the pH-sensitive covalent bond is selected from the group consisting of: Method of Administration of the Vectors The vectors are administered parenteraUy through systemic and local injection routes and they also may be administered ex-vivo. In vitro and in vivo testing of the Vectors Methods of in vitro testing of the vectors of the invention are weU known in the art. For example, they can be tested for the abiUty to provide deUvery to cells and tissues in culture as described in Examples 35 and 44 or they can be tested for coUoidal and physicochemical properties as described in Examples 40 and 42. Methods of measuring the in vivo efficacy of the vectors of the invention are weU known in the art. For example, when the vectors are used for the treatment of a disease in a mammal, efficacy of the vector can be determined by study of the ameUoration of one or more symptoms of the disease. Advantageously, the in vivo efficacy can use measurement of defined clinical end points that are characteristic of the progress or extent of a disease. A gene deUvery vector displays "fusogenic activity" in vitro or in vivo within the meaning of the invention if it is capable of transferring a nucleic acid into a ceU or tissue in vitro or in vivo. However, fusogenic activity may also be assessed by methods known in the art which do not rely on the measurement of the nucleic acid transferred by the vector. For example, the methods employed in Lackey et al., Proc. Int. Symp. Control. Rel. Bioact. Mater. 1999, 26, #6245; Meyer et al., FEBSLett. 421:61 (1999) and Richardson et al., Proc. Int. Symp. Control. Rel. Bioact. Mater. 1999, 26, §251 may be used to assess the fusogenic activity of vectors of the invention. As a general reference the person skiUed in the art, when contemplating issues related to membrane fusion, wiU consider H. Hilderson and S. FuUer eds., Series editor J. Robin Harris, Fusion of Biological Membranes and Related Problems, Subcellular Biochemistry Vol. 34., Kluwer Academic Plenum Publishers, New York, 2000. Particular reference in this volume is made to H. Kubista, S. Sacre, and S.E. Moss, Annexins and Membrane Fusion, p 73-131; P. CoUas and D. Poccia, Membrane Fusion Events during Nuclear Envelope Assembly, p 273-302; Y. Gaudin, Reversibility in Fusion Protein Conformational Changes: The Intriguing Case of Rhabdovirus-Iduced Membrane Fusion, p379- 408. Furthermore, P. CoUas and D. Poccia, DevBiol 1995 May;169(l):123-35 and P. CoUas and D. Poccia, Methods Cell Biol. 1998;53:417-52 describe measurement of fusogenic activity. The use of resonance energy transfer to monitor membrane fusion is further described in Pecheur El, Martin I, Ruysschaert JM, Bienvenue A, Hoekstra D. Biochemistry 37, 2361-2371 (1998) and Struck DK, Hoekstra D, Pagano RE. Biochemistry 20, 4093-4099 (1981). If the FRET technology is used to assess the fusogenic activity of a vector of the invention, preferredly the measured output signal is increased by at least 2fold and more preferredly by at least 3fold, and more preferredly by at least 4fold, as compared to a non-fuso genie control vector. A gene deUvery vector displays "biological activity" in vitro or in vivo if contacting a ceU with the vector results in the expression of a transferred nucleic acid in said ceU or tissue in vitro or in vivo. Methods of measuring the fusogenic andor biological activities of the vectors of the invention are weU known in the art and are further described in the examples hereinbelow. In particular, methods relying on the direct or indirect identification of a gene product encoded by a marker gene deUvered by the vector are suitable to assess whether or not a vector of the invention displays biological activity. Preferredly at least 5% of the ceUs contacted with the vector of the invention in vitro express the marker gene. More preferred are expression rates of at least 20%, 50% and 80% of the ceUs contacted with the vector of the invention in vitro. If a tissue is treated with a vector of the invention in vitro or in vivo, it is preferred that at least 5% of the ceUs, preferredly at least 20%, 50% and 80% of the parenchymatic ceUs of said tissue express the marker gene. Any gene encoding a detectable gene product may serve as a suitable marker gene. The choice of a suitable marker gene is deemed to be within the routine capabiUties of the person skiUed in the art. These and other features and advantages of the invention wiU be more fuUy appreciated with the foUowing examples, which are provided for iUustrative purposes only, and are not intended to be limiting of the scope of the invention. The foUowing examples Ulustrate the present invention; the temperatures are given in degrees Celsius. The foUowing abbreviations are used: BOC = tert.-butyloxycarbonyl; THF = tetrahydrofuran; hexane = n-hexane; ether = diethyl ether. Concerning nomenclature: when numbering the different nitrogen atoms, the terminal amino nitrogens are treated as substituents of the terminal carbon atoms, whUe the non-terminal nitrogen atoms are interpreted as aza substitutions of CH 2 groups and are numbered accordingly. Therefore e.g. the 4 nitrogen atoms in spermine are designated N 1 , N 4 , N 9 and N ]2 : 1 4 9 12 H 2 N-CH 2 -(CH 2 ) 2 -NH-(CH 2 ) 4 -NH-(CH 2 ) 2 -CH 2 -NH 2 (1 ,12-diamino-4,9-diazadodecane) Example 1: N 4 -[(2-hydroxy)-n-tetradecyl]-speπnidine trihydrochloride A solution of 6 g (0.1646 moles) of hydrogen chloride in 50 ml of ethyl acetate was added whUst stirring, at room temperature, to a solution of 8.8 g (0.0158 moles) of N I ,N 8 -di-BOC-N 4 -[(2-hydroxy)-n-tetradecyl]-spermidine in 50 ml of ethyl acetate. After stirring for 1.25 hours, the crystals that had precipitated from the reaction mixture were filtered. The hygroscopic crude product was dissolved in water and chromatographed on a column charged with Amberhte XAD 1180 adsorber resin (in water), whereby elution took place first of aU with water and then with a mixture of water and isopropanol (9: 1 or 3:1). The fractions containing the product were combined, concentrated in a water jet vacuum, and lyophilized under a high vacuum. The title compound was obtained as a lyophilizate with a water content of 4.25%, R f : 0.25 [thin-layer chromatography plates siUca gel 60 F 5 4 ; solvent: methylene chloride/methanol/30% aqueous ammonia solution (10:3.5:1)]. The starting compounds were produced as foUows: a) N^N^di-BOC-^-^-hydroxyl-n-tetradecyn-spermidύie 12.49 g (0.05 moles) of 1,2-tetradecene oxide (85%) were added to a solution of 17.27 g (0.05 moles) of N l ,N 8 -di-BOC-spermidine in 200 ml of ethanol. The reaction mixture was heated for 2 hours under reflux and then a further 3.44 g (0.01377 moles) of 1,2-tetradecene oxide were added. After heating for 16.5 hours under reflux, the reaction mixture was concentrated by evaporation. Purification of the oUy crude product was effected by flash chromatography on sihca gel of grain size 0.04 - 0.063 mm. The product-containing fractions which have been eluted with a methylene chloride/methanol mixture (19:1) were combined and concentrated by evaporation under vacuum. The title compound was obtained in the form of an oU, R f : 0.80 [solvent: methylene chloride/methanol/30% aqueous ammonia solution (40:10:1)]. b) N 1 .N 8 -di-BOC-spermidine A solution of 221.67 g (0.90 moles) of 2-(BOC-oxyimino)-2- phenylacetonitrile in 630 ml of THF was added dropwise at 0-5° whUst stirring, under a nitrogen atmosphere, over the course of 2 hours, to a solution of 65.34 g (0.45 moles) of spermidine in 630 ml of THF. The reaction mixture was stirred for 16 hours at room temperature, then concentrated by evaporation under vacuum and the oUy residue was partitioned between ether and dUuted hydrochloric acid (pH 3). The phase containing hydrochloric acid was rendered basic with 30% sodium hydroxide solution (pH 10), the desired product was extracted with ether, the ether extract washed with saturated sodium chloride solution, the organic phase dried over sodium sulfate and concentrated by evaporation under vacuum. After recrystalUzation of the residue from ether-hexane, the title compound was obtained, m.p. 85-86°. By concentrating the mother Uquor, a second batch of the title compound was obtained, m.p. 78-82°. Example 2: N 4 -[(2-hydroxy)-n-tetradecyl]-speπnidine trioxalate A solution of 10.17 g (0.08067 moles) of oxaUc acid dihydrate in 90 ml of water was added whilst stirring to a solution of 15 g (0.02689 moles) of N^N^di- BOC-N 4 -[(2-hydroxy)-n-tetradecyl)]-spermidine (example la) in 30 ml of ethanol. The reaction mixture was stirred for 5 hours at 90° and subsequently concentrated under vacuum. After cooling to 0°, the title compound precipitated in crystalUne form from the concentrate which had been mixed with ethanol, nxp. 180°(decomp.). Example 3: N 5 -[(2-hydroxy)-n-decyl]-homospermidine trihydrochloride A solution of 1.276 g (0.035 moles) of hydrogen chloride in 10 ml of ethyl acetate was added whUst stirring, at room temperature, to a solution of 2.89 g (0.0056 moles) of N 1 ,N 9 -di-BOC-N 5 -[(2-hydroxy)-n-decyl]-homospermidine in 10 ml of ethyl acetate. Stirring was effected for 20 minutes at room temperature and for 20 minutes at 0°. The precipitated product was filtered, washed with cold ethyl acetate, dissolved in water and chromatographed with water on a column charged with AmberUte XAD 1180 adsorber resin. After lyophilization of the combined product-containing fractions, the title compound was obtained with a water content of 4.5%, Rf. 0.28 (solvent as for example 1). The starting compounds were produced as foHows: a) N 1 .N 9 -di-BOC-N 5 -[ 2-hydroxy)-n-decyl]-homospermidine 2.63 g (0.0168 moles) of 1,2-decene oxide were added to a solution of 5.03 g (0.014 moles) of N^N 9 -di-BOC-homospermidine in 50 ml of ethanol. The reaction mixture was boded under reflux for 22 hours, then a further 0.52 g (0.00333 moles) of 1,2-decene oxide were added, heating continued for 18 hours under reflux and then the mixture was concentrated by evaporation under vacuum. Purification of the oUy crude product was effected by flash chromatography on siUca gel. Elution was carried out with methylene chloride and methylene chloride/methanol mixtures with a methanol content of 1%, or 2.5%, or 5%, or 10%. The title compound was obtained in the form of an oU, Rf: 0.39 [solvent: methylene chloride/methanol (9:1)]. b) N 1 .N 9 -di-BOC-homospermidine 17 g of paUadium on activated carbon (10% Pd) were added to a solution of 167.7 g (0.373 moles) of N 5 -benzyl-N 1 ,N 9 -di-BOC-homospermidine (Bergerone et al, Synthesis 1982:689) in a mixture of 1200 ml of methanol and 31.9 ml of cone. hydrochloric acid, and hydrogenation was carried out at 30° untU the hydrogen uptake has ended. After filtration and evaporation of the filtrate to dryness, the crystalUne residue (hydrochloride of the title compound) was dissolved in 2 Utres of water and the aqueous solution (pH 4) was adjusted to pH 3 by adding 4N hydrochloric acid. The product was washed with ether, the aqueous phase adjusted to pH 10 by adding 30% sodium hydroxide solution, and the oiled product was extracted with three portions of ether, each of 500 ml. After washing the combined ether phases with cone, aqueous sodium chloride solution, drying over sodium sulfate and evaporating under vacuum, the title compound was obtained in the form of an oU which graduaUy crystallized, m.p. 42-46°. Example 4: N s -[(2-hydroxy)-n-decyl]-homospeπnidine-trioxalate A solution of 4.54 g (0.036 moles) of oxaUc acid dihydrate in 30 ml of water was added whUst stirring to a solution of 6.19 g (0.012 moles) of N 1 ,N 9 -di-B0C-N 5 - [(2-hydroxy)-n-decyl]-homospermidine (example 3a) in 30 ml of ethanol. The reaction mixture was heated under reflux for 23 hours, and then concentrated by evaporation under vacuum. Purification of the crude product takes place analogously to example 1 on AmberUte XAD 1180 adsorber resin [eluant: H 2 0 and H 2 0/isopropanol (19:1 or 4:1)]. After lyophilization, the title compound was obtained with a water content of 3.8%, R f : 0.28 (solvent as for example 1). Example 5: N s -[(2-hydroxy)-n-hexadecyl]-homospeπnidine-tri-(toluene-4- sulfonate) A mixture of 21.48 g (0.0358 moles) of N 1 ,N 9 -di-BOC-N 5 -[(2-hydroxy)-n- hexadecyl]-homospermidine and 20.43 g (0.1074 moles) of toluene-4-sulfbnic acid monohydrate in 120 ml of water was heated for 11.5 hours at 70° whUst stirring, and subsequently concentrated to a volume of ca. 30 ml. Purification of the concentrate was effected analogously to example 1 on AmberUte XAD 1180 adsorber resin [eluant: H 2 0 and H 2 O/isopropanol (4:1 or 3:2)]. The title compound was obtained as a lyophiUzate with a water content of 2.8%, R f : 0.32 (solvent as in example 1). The starting compound was produced as foUows: a) N'.N^di-BOC-^-f^-hydroxyVn-hexadecyll-homospermidine 15.91 g (0.0562 moles) of 1,2-hexadecene oxide (85%) were added to a solution of 13.48 g (0.0375 moles) of N^N 9 -ά -BOC-homosρermidine (example 3b) in 150 ml of ethanol, the reaction mixture was bofled under reflux for 20 hours and then concentrated by evaporation under vacuum. Purification of the oily crude product was effected by flash chromatography on silica gel, whereby the eluants used were ethyl acetate/hexane mixtures (1:3 or 1:2 or 1:1) and ethyl acetate. The title compound was obtained in the form of an oU, R f : 0.45 (solvent as in example 3a). Example 6: N 5 -[(2-hydroxy)-n-hexyl]-homospermidine trioxalate A solution of 4.6 g (0.0365 moles) of oxaUc acid dihydrate in 40 ml of water was added to a solution of 5.6 g (0.01218 moles) of N 1 ,N 9 -di-BOC-N s -[(2- hydroxy)-n-hexyl]-homo-spermidine in 20 ml of ethanol, the reaction mixture was heated under reflux for 4.5 hours, and then concentrated by evaporation under vacuum. The crude product obtained was dissolved in methanol and precipitated by the dropwise addition of ether. FUtration was carried out and the title compound was recrystaUized from ethanol/water, m.p. 85-90°. The starting compound was produced as foUows: a) N^N 9 -di-BOC-N 5 -[(2-hydroxyVn-hexyll-homospermidine 1.80 g (0.018 moles) of 1,2-hexene oxide were added to a solution of 4.31 g (0.012 moles) of NSN 9 -di-BOC-homospermidine (example 3b) in 40 ml of ethanol, the reaction mixture was boUed under reflux for 22 hours and then concentrated by evaporation under vacuum. The oUy residue was purified by flash chromatography on silica gel, using methylene chloride/methanol mixtures (99:1 or 19:1 or 9:1). The title compound was obtained in the form of an oU, R f : 0.32 (solvent as in example 3a). Example 7: N s -[(2-hydroxy)-n-butyl]-homospern__idine-tri-(toluene-4- sulfonate) A mixture of 6.39 g (0.0148 moles) of N 1 ,N 9 -di-BOC-N 5 -[(2-hydroxy)-n- butyl]-homospermidine and 8.45 g (0.0444 moles) of toluene-4-sulfonic acid monohydrate in 30 ml of water was heated at 75° for 3.5 hours whilst stirring, then after cooling it was adjusted to pH 6 with IN sodium hydroxide solution, and concentrated under vacuum. Purification of the concentrate was effected analogously to example 1 on AmberUte XAD 1180 adsorber resin [eluant: water and water/isopropanol (9:1)]. The title compound was obtained as a lyophilizate with a water content of 1.4%; R f : 0.14 (solvent as in example 1). The starting compound was produced as foUows: a) N 1 .N 9 -di-BOC-N 5 -rr2-hydroxyVn-butyll-homospermidine 1.51 g (0.021 moles) of 1,2-butene oxide were added to a solution of 5.39 g (0.015 moles) of N 1 ,N 9 -di-BOC-homospermidine (example 3b) in 50 ml of ethanol. The reaction mixture was heated at 80° for 5 hours, then a further 0.36 g (0.005 moles) of 1,2-butene oxide were added, heating continued for 15 hours at 80°, and the mixture was concentrated by evaporation under vacuum. Purification of the crude product was effected by flash chromatography on siUca gel, using methylene chloride/methanol mixtures (50:1 or 20:1 or 10:1). The title compound was obtained in the form of an oU, R f : 0.20 (solvent as in example 3a). Example 8: N 5 -[(2-hydroxy)-n-octyI]-homospermidine trioxalate A solution of 3.64 g (0.0289 moles) of oxaUc acid dihydrate in 36 ml of water was added whUst stirring to a solution of 4.7 g (0.00963 moles) of N*,N 9 -di- BOC-N 5 -[(2-hydroxy)-n-octyl]-homospermidine in 12 ml of ethanol, the reaction mixture was heated at 90° for 4.5 hours, and then concentrated by evaporation under vacuum. After recrystaUisation of the residue from ethanol, the title compound was obtained with a water content of 2.2%, m.p. 83-85°. The starting compound was produced as foUows: a) N N 9 -di-BOC-N 5 -[(2-hydroxyVn-octyl1-homospermidine 2.31 g (0.018 moles) of 1,2-octene oxide were added to a solution of 5.39 g (0.015 moles) of N\N 9 -di-BOC-homospermidine (example 3b) in 50 ml of ethanol. The reaction mixture was heated at 80° for 15 hours, then a further 0.39 g (0.00304 moles) of 1 ,2-octene oxide were added, heating continued for 8 hours at 80°, and the mixture was concentrated by evaporation under vacuum Purification of the crude product was effected analogously to example 7a. The title compound was obtained in the form of an oU, Rf: 0.35 (solvent as in example 3a). Example 9: N s -[(2-hydroxy)-n-hexadecyI]-N 1 ,N 1 ,N 9 ,N 9 -tetramethyl- homospermidine-tri-(toIuene-4-sulfonate) 11.8 ml (0.15 moles) of a 35% solution of formaldehyde in water arid 0.75 g of paUadium on activated carbon (10% Pd) were added to a solution of 2.83 g (0.003 moles) of N 5 -[(2-hydroxy)-n-hexadecyl]-homospermidine-tri-(toluene-4- sulfonate) (example 5) in 20 ml of water. Hydrogenation was carried out at room temperature untU the hydrogen uptake has ended. FUtration was effected, the filtrate was concentrated by evaporation under vacuum, and the residue was partitioned between 2N sodium hydroxide solution and ethyl acetate. The organic phase which was washed with concentrated aqueous sodium chloride solution and dried over sodium sulfate was concentrated by evaporation, the residue dissolved in methanol and the methanoUc solution adjusted to a pH value of 3 by adding 2N hydrochloric acid. After evaporation under vacuum and recrystaUization of the residue from methanol/ether, the title compound was obtained, m.ρ. 236-239°. Example 10: N -[(2-hydroxy)-n-decyl]-N 1 ,N 1 ,N 8 ,N 8 -tetramethyl-spermidine trioxalate 1.6 g (0.002745 moles) of N 4 -[(2-hydroxy)-n-decyl]-spermidine trioxalate (example 27) were reacted analogously to example 9 with 11.8 ml (0.15 moles) of a 35% solution of formaldehyde in water. After concentrating by evaporation, the residue was crystallized from acetonitrile. After recrystaUization from methanol/acetonitrile, the title compound was obtained with a water content of 1.69%, m.p. 118-121°. Example 11: N 1 ,N 4 -bis-(3-aminopropyl)-N 1 ,N 4 -bis[(2-hydroxy)-n-hexadecyl]- l,4-diamino-trans-2-butene-trioxaIate A mixture of 2.7 g (0.00306 moles) of N^-bisP-BOC-aminopropyl]- N 1 ,N 4 -bis[(2-hydroxy)-n-hexadecyl]-l,4-diamino-trans-2-butene, 1.16 g (0.0092 moles) of oxaUc acid dihydrate and 30 ml of water was reacted analogously to example 13 (duration of reaction: 18 hours). The title compound, which was recrystallized a second time from ater/acetonitrile, contains 2.3% water, p. 165° (decomp.). The starting compounds were produced as foUows: a) N\N -bisr3-BOC-aminopropyll-N 1 .N 4 -bisr(2-hydroxyVn-hexadecyll-1.4- diamino-trans-2-butene A mixture of 2 g (0.005 moles) of N 1 ,N 4 -bis[3-BOC-aminoρropyl]- 1 ,4- diamino-trans-2-butene, 3.54 g (0.0125 moles) of 1,2-hexadecene oxide (85%) and 40 ml of ethanol was boned under reflux for 24 hours and subsequently concentrated by evaporation under vacuum. After purification of the residue by flash chromatography on silica gel, using methylene chloride/methanol mixtures (100:1 or 25:1), the title compound was obtained in the form of an oU, which soUdified into crystalline form after a short time, m.p. 85-87°. b) N N^bisrS-BOC-aminopropyll-N'-BOC-l -diamino-trans^-butene and N 1 ,N -bis f3-B OC-aminopropyn- 1.4-diamino-trans-2-butene A solution of 46.18 g (0.1875 moles) of 2-(BOC-oxyimino)-2- phenylacetonitrile in 150 ml of THF was added dropwise whilst stirring, over the course of 3 hours, and in a nitrogen atmosphere, to a solution, cooled to 0-5°, of 15.02 g (0.075 moles) of N 1 ,N 4 -bis(3-aminoρropyl)-l,4-diamino-trans-2-butene in 100 ml of THF. The reaction mixture was stirred for a further 3.5 days at room temperature, then concentrated by evaporation under vacuum and the residue was separated by flash chromatography on silica gel, using methylene chloride/methanol mixtures (39:1 or 9:1) and mixtures of methylene chloride/methanol/30% aqueous ammonia solution (90:10:0.25 or 10:5:1). The first title compound, N\N 4 -bis[3- BOC-aminopropyl]-N 1 -BOC-l,4-diamino-trans-2-butene, was thereby obtained in the form of an oU, R f : 0.87 (solvent as in example la), and the second title compound, N\N 4 -bis[3-BOC-aminopropyl]-l,4-diamino-trans-2-butene, was also obtained in the form of an oU, R f : 0.26 (solvent as in example la). Example 12: N 1 ,N 4 -bis(3-aminopropyI)-N 1 -[(2-hydroxy)-n-hexadecyI]-l,4- diamino-trans-2-butene-tetraoxalate The title compound was obtained analogously to example 11, from 1.58 g (0.00213 moles) of N^-bisβ-BOC-aminopropyll-N^BOC-N 4 -^- hydroxy)-n-hexadecyl]-l,4-diamino-trans-2-butene, 1.075 g (0.00853 moles) of oxaUc acid dihydrate and 20 ml of water. M.p. 185° (decomp.). The starting compound was produced as foUows: a) N 1 .N 4 -bisr3-BOC-aminopropyll-N 1 -BOC-N 4 -rr2-hvdroxy -n-hexadecyl]- 1.4-diamino-trans-2-butene The title compound was obtained in the form of an oU, analogously to example 11a, from 2.5 g (0.005 moles) ofN^-bistS-BOC-aminopropylJ-N'-BOC-M- diamino-trans-2-butene and 1.77 g (0.00626 moles) of 1,2-hexadecene oxide (85%). Rf: 0.59 (solvent as in example 3a). Example 13: N 4 -[(2-hydroxy)-n-hexadecyl]-N 9 -octyl-spermine tetraoxalate A mixture of 1.08 g (0.00143 moles) of N 1 ,N 1 -di-BOC-N 4 -[(2-hydroxy)- n-hexadecyl]-N 9 -n-octyl-spermine, 0.721 g (0.00577 moles) of oxaUc acid dihydrate and 20 ml of water was heated under reflux for 16 hours and subsequently mixed with acetonitrUe (untU sUght turbidity occurs). The product which precipitated upon cooling was filtered, washed with acetonitrUe and dried under a high vacuum at 100°. The title compound obtained contained 1.6% water, m.p. 170-180° (decomp.). The starting compounds were produced as foUows: a) N\N 12 -di-BOC-N 4 -rr2-hydroxy n-hexadecyl1-N 9 -n-octyl-sρermine A mixture of 1.3 g (0.00202 moles) of N 1 ,N I2 -di-BOC-N 4 -[(2-hydroxy)-n- hexadecylj-spermine, 0.444 g (0.0023 moles) of 1-bromoctane, 1.1 g (0.00796 moles) of potassium carbonate and 20 ml of acetonitrUe was heated under reflux for 16 hours. A further 0.089 g (0.00046 moles) of 1-bromoctane were added to the reaction mixture, and heating continued under reflux for a further 6 hours. After the further addition of 0.089 g (0.00046 moles) of 1-bromoctane and heating under reflux for 14 hours, the reaction mixture was concentrated by evaporation under vacuum. Purification of the residue was carried out using flash chromatography on siUca gel, using methylene chloride/methanol mixtures (50: 1 or 9:1) and a mixture of methylene chloride/methanol/30% aqueous ammonia solution (90:10:0.25). The title compound was obtained in the form of an oU, R f : 0.76 [solvent: toluene/isopropanol/30% aqueous ammonia solution (70:29:1)]. b) N 1 .N 12 -di-BOC-N 4 -rt2-hydroxyVn-hexadecyll-spermine and N'.N 12 -di- BOC-N 4 .N 9 -bis-r(2-hydroxyVn-hexadecyl1-spermine 3.21 g (0.01136 moles) of 1,2-hexadecene oxide (85%) were added to a solution of 3.98 g (0.00989 moles) of N\N 12 -di-BOC-spermine in 40 ml of ethanol, the reaction mixture was boUed under reflux for 20 hours and then concentrated by evaporation under vacuum. Upon chromatography of the crude mixture on silica gel, using methylene chloride/methanol mixtures (100:1 or 9:1), first of aUN\N 12 - di-BOC-N 4 ,N 9 -bis-[(2-hydroxy)-n-hexadecyl]-spermine elutes, R f : 0.31 (solvent as in example 3a), and then using mixtures of methylene chloride/methanol/30% aqueous ammonia solution (90:10:0.25 or 40:10:0.5), N\N 12 -di-BOC-N 4 -[(2-hydroxy)-n-hexadecyl]-spermine elutes, R f : 0.07 (solvent as in example 13a). c) N'.N 9 .N 12 -tri-BOC-spermine and N'.N^-di-BOC-spermine 50 g (0.2471 moles) of spermine were dissolved in 300 ml of THF under a nitrogen atmosphere, wmlst stirring, and then at 0-5°, a solution of 134 g (0.544 moles) of 2-(BOC-oxyimino)-2-phenylacetonitrUe in 500 ml of THF was added dropwise over the course of one hour. The reaction mixture was stirred for a further 16 hours at room temperature and then concentrated by evaporation under vacuum. Upon separation of the reaction mixture by flash chromatography on siUca gel, using methylene chloride, methylene chloride/methanol mixtures (97.5:2.5 or 9:1) and mixtures of methylene chloride/methanol/30% aqueous ammonia solution (90: 10:0.5 or 20: 10: 1), the foUowing were obtained: oUy N 1 JN 9 ,N 1 -tri-BOC- spermine [see J. Org. Chem. 50, 5735 (1985)], Rf: 0.78 (solvent as in example la), sUghtly impure N\N 12 -di-BOC-spermine, m.p. 86-88° and pure N 1 ,N 12 -di-BOC- spermine, m.p. 91-92°. d) N ,N -di-BOC-spermine may also be produced in the foUowing manner: 18.4 g (0.0196 moles) of N'^.N'.N^-tetrakisOjenzyloxycarbony^-N'^^-di- BOC-spermine were dissolved in 200 ml of methanol. After adding 1.8 g of paUadium on activated carbon (10% Pd), hydrogenation was carried out at room temperature until the hydrogen uptake had ended. The solution was filtered and the filtrate was concentrated by evaporation under vacuum. The oUy title compound, R f : 0.09 (solvent as in example la), which graduaUy changed into a crystalline state, was identical to the obtained according to example 13c. e) N 1 .N 4 .N 9 .N 12 -tetrakis(benzyloxycarbonyl)-N 1 .N 12 -di-BOC-spermine 0.57 g (0.00466 moles) of 4-dimethylaminopyridine and a solution of 11.24 g (0.0515 moles) of di-(tert.-butyl)-dicarbonate in 25 ml of acetonitrUe were added whUst stirring to a solution of 17.3 g (0.0234 moles) of N'jNW.N 12 - tetraMs(benzyloxycarbonyl)-spermine in 40 ml of acetonitrUe. The reaction mixture was stirred at room temperature for 18 hours, subsequently concentrated by evaporation, and the residue was purified by flash chromatography on siUca gel, using hexane/ethyl acetate mixtures (4:1 or 3:1 or 2:1 or 1:1). The title compound was obtained in the form of an oU, Rf: 0.38 [solvent: ethyl acetate/hexane (1:1)]. f) N\N 4 .N 9 .N 12 -tetraMsfl3enzyloxycarbonylVspermine 82.82 ml (0.25 moles) of chloroformic acid benzyl ester (50% in toluene) were added dropwise at room temperature, over the course of one hour, to a weU stirred solution of 10.12 g (0.05 moles) of spermine and 39.75 g (0.375 moles) of sodium carbonate in 200 ml of water. The reaction mixture was stirred for 4 hours, filtered and the organic phase separated. This phase was washed with water and with concentrated aqueous sodium chloride solution, dried over sodium sulfate, and concentrated by evaporation under vacuum. Purification of the residue was effected by flash chromatography on siUca gel, using ethyl acetate/hexane mixtures (1:3 or 1:2 or 1:1). The title compound was obtained in the form of an oU, R f : 0.37 [solvent: ethyl acetate/hexane 2:1)]. Example 14: N s -(2-hydroxyethyl)-homospermidine trioxalate The title compound was obtained analogously to example 8, from 2.6 g (0.00644 moles) of N I ,N 9 -di-BOC-N 5 -(2-hydroxyethyl)-homospermidine and 2.435 g (0.0193 moles) of oxaUc acid dihydrate. M.p. 127-130°. The starting compound was produced as foUows: a) N^N 9 -di-BOC-N 2-hvdroxyethy1Vhomospermidine 3.2 g (0.0726 moles) of ethylene oxide were passed into a solution, cooled to 5°, of 7.19 g (0.02 moles) of N^N 9 -di-BOC-homospermidine in 25 ml of methanol over the course of ca. 20 minutes. The reaction mixture was stirred for 21 hours at room temperature and subsequently concentrated by evaporation under vacuum. Purification of the residue was effected by flash chromatography on silica gel, using methylene chloride/methanol mixtures (30:1 or 10:1 or 5:1). The title compound was obtained in the form of an oU, R f : 0.07 (solvent as in example 3a). Example 15: N ,N 9 -bis[(2-hydroxy)-n-octyl] -spermine tetraoxalate A solution of 1.26 g (0.01 moles) of oxaUc acid dihydrate in 10 ml of water was added to a solution of 1.65 g (0.0025 moles) of N 1 ,N 12 -di-BOC-N 4 ,N 9 -bis[(2- hydroxy)-n-octyl]-spermine in 5 ml of ethanol. The reaction mixture was stirred for 9 hours at 90°, then concentrated by evaporation under vacuum, and the residue was crystallized from methanol ether. The title compound obtained melted at 126- 129°. The starting compound was produced as foUows: a) N^N t2 -di-BOC-N 4 .N 9 -bisrf2-hvdroxyVn-octyll-spermine A mixture of 1.01 g (0.0025 moles) of N\N 12 -di-BOC-sρermine, 0.96 g (0.0075 moles) of 1,2-octene oxide and 15 ml of ethanol was stirred for 1 hours at 85° and subsequently concentrated by evaporation under vacuum. Purification of the residue was effected by flash chromatography on silica gel, using methylene chloride/methanol mixtures (19:1 or 9:1). The title compound was obtained in the form of an oil, R f : 0.23 (solvent as in example 3a). Example 16: N ,N 9 -bis[(2-hyd_roxy)-n-decyl]-speπnine tetraoxalate A solution of 3.73 g (0.0296 moles) of oxaUc acid dihydrate in 10 ml of water was added to a solution of 5.3 g (0.00741 moles) of N^-di-BOC-N^N 9 - bis[(2-hydroxy)-n-decyl]-spermine hi 10 ml of ethanol. The reaction mixture was stirred for 10 hours at 90°, then concentrated by evaporation, and the residue crystallized from methanol/ether. The title compound obtained melts at 175-177°. The starting compound was produced as foUows: a) N 1 .N 12 -di-BOC-N 4 .N 9 -bisrr2-hvdroxyVn-decvn-spermine A mixture of 3.22 g (0.008 moles) of N\N 12 -di-BOC-spermine, 3.75 g (0.024 moles) of 1,2-decene oxide and 32 ml of ethanol was stirred for 19 hours at 80° and subsequently concentrated by evaporation under vacuum. Purification of the residue was effected by flash chromatography on silica gel, using methylene chloride and methylene chloride/methanol mixtures (50:1 or 19:1 or 9:1). The title compound was obtained in the form of an oU, R f : 0.25 (solvent as in example 3a). Example 17: N 4 ,N 9 -bis[(2-hydroxy)-n-dodecyl]-spermine-tetraoxalate The title compound was obtained analogously to example 15, but maintaining the reaction for 10 hours, from 1.7 g (0.0022 moles) of N'.N^-di- BOC-N 4 ,N 9 -bis[(2-hydroxy)-n-dodecyl]-spermine and 1.11 g (0.0088 moles) of oxalic acid dihydrate. M.p. 187° (decomp.). The starting compound was produced as foUows: a) N 1 .N 12 -di-BOC-N 4 .N 9 -bisrr2-hvdroxyVn-dodecyll-spermine 1.01 g (0.0025 moles) of ^N 12 -di-BOC-spermine and 1.38 g (0.0075 moles) of 1,2-dodecene oxide were reacted analogously to example 15a (duration of reaction: 22 hours). The title compound which was purified by flash chromatography on siUca gel [eluant: methylene chloride/methanol (99:1 or 19:1)] was obtained in the form of an oU, R : 0.27 (solvent as in example 3a). Example 18: N 4 ,N 9 -bis[(2-hydroxy)-n-tetradecyl]-spermine tetraoxalate 1.82 g (0.0022 moles) of N 1 ,N 12 -di-BOC-N 4 ,N 9 -bis[(2-hydroxy)-n- tetradecyl] -spermine and 1.11 g (0.0088 moles) of oxaUc acid dihydrate were reacted analogously to example 15, but maintaining the reaction for 11.5 hours. After crystallization from methanol/water, the title compound decomposed at 170°. The starting compound was produced as foUows: a) N\N 1 -di-BOC-N 4 .N 9 -bisrr2-hydroxyVn-tetradecyl1-spermine 1.01 g (0.0025 moles) of N 1 ,N 12 -di-BOC-spermine and 1.874 g (0.0075 moles) of 1,2-tetradecene oxide (85%) were reacted analogously to example 15a (duration of reaction: 18.5 hours). The title compound which was purified by flash chromatography on siUca gel [eluant: methylene chloride/methanol (99:1 or 49:1 or 19:1 or 9:1)] was obtained in the form of an oU, Rf.- 0.30 (solvent as in example 3a). Example 19: N 4 ,N 9 -bis[(2-hydroxy)-n-hexadecyl]-spermine tetraoxalate A mixture of 3.53 g (0.004 moles) of N 1 ,N 12 -di-BOC-N 4 ,N 9 -bis[(2-hydroxy)-n- hexadecyl]-spermine, 3.04 g (0.016 moles) of toluene-4-sulfonic acid monohydrate and 20 ml of water was stirred for 19 hours at 70°, subsequently concentrated by evaporation under vacuum, and the residue partitioned between 2N sodium hydroxide solution and chloroform. After washing the organic phase with concentrated sodium chloride solution, drying over sodium sulfate and concentrating by evaporation under vacuum, crude N 4 ,N 9 -bis[(2-hydroxy)-n- hexadecyl]-spermine was obtained, which was dissolved in 32 ml of ethanol and mixed, whUst stirring, with a solution of 2.0 g (0.016 moles) of oxaUc acid dihydrate in 32 ml of ethanol, whereby the title compound precipitated in crystalline form. The crystalUzate which was washed with ethanol and dried under a high vacuum melted at 140° under decomposition. The starting compound was produced as foUows: a) N^N 12 -α^-BOC-N 4 .N 9 -bisr(2-hydroxy>-n-hexadecyl1-spermine 2.02 g (0.005 moles) of ^N^-di-BOC-spermine and 4.24 g (0.015 moles) of 1,2- hexadecene oxide (85%) were reacted analogously to example 15a (duration of reaction: 8 hours). The title compound which was purified by flash chromatography on siUca gel, using ethyl acetate/hexane mixtures (1:3 or 1:2 or 1:1), using ethyl acetate and using an ethyl acetate/methanol mixture (19: 1), was obtained in the form of an oil, R : 0.31 (solvent as in example 3a). Example 20: N 4 -[(2-hydroxy)-n-hexadecyl]-speπnine-tetra(toluene-4- sulfonate) A mixture of 5.94 g (0.008 moles) of N I ,N 9 ,N 12 -tri-BOC-N 4 -[(2-hydroxy)- n-hexadecyl]-spermine, 6.09 g (0.032 moles) of toluene-4-sulfonic acid monohydrate and 35 ml of water was reacted analogously to example 5 (duration of reaction: 2.5 hours). After purification on AmberUte XAD 1180 adsorber resin, using water and water/isopropanol mixtures (9:1 or 4:1 or 3:2), the title compound was obtained as a lyophilizate with a water content of 2.24%, Rf: 0.07 (solvent as in example 1). The starting compound was produced as foUows: a N 1 .N 9 .N 12 -tri-BOC-N 4 -[f2-hvdroxyVn-hexadecvn-spermine N -ff2- hydroxyVn-decyll-spermine tetraoxalate 5.02 g (0.01 moles) of N N 9 ,N 12 -tri-BOC-spermine and 4.24 g (0.015 moles) of 1,2-hexadecene oxide (85%) were reacted analogously to example 15a (duration of reaction: 10.5 hours). The title compound which was purified by flash chromatography on siUca gel, using ethyl acetate hexane mixtures (1 :3 or 1: 1) and using ethyl acetate, was obtained in the form of an oU, R f : 0.52 (solvent as in example 3a). A mixture of 4.05 g (0.00615 moles) of N 1 ,N 9 ,N 12 -tri-BOC-N 4 -[(2- hydroxy)-n-decyl]-spermine, 3.1 g (0.0246 moles) of oxaUc acid dihydrate, 8 ml of ethanol and 8 ml of water was reacted analogously to example 15 (duration of reaction: 12.5 hours). After crystalUsation from ethanol/ether, the title compound decomposed at 135-155°. The starting compound was produced as foUows: a) N 1 .N 9 .N 12 -tri-BOC-N 4 -rf2-hvdroxyVn-decyn-spermine A mixture of 4.02 g (0.008 moles) of N 1 ,N 9 ,N 12 -tri-BOC-spermine, 1.875 g (0.012 moles) of 1,2-decene oxide and 40 ml of ethanol was stirred for 20 hours at 80° and subsequently concentrated by evaporation under vacuum. After purifying the residue by flash chromatography on silica gel, using methylene chloride and methylene chloride/methanol mixtures (50:1 or 19:1 or 9:1), the title compound was obtained in the form of an oU, R f .- 0.40 (solvent as in example 3a). Example 22: N 4 -[(R)-(2-hydroxy)-n-hexadecyl]-spermine tetraoxalate A mixture of 5.6 g (0.00754 moles) of N 1 ,N 9 ,N 12 -tri-BOC-N 4 -[(R)-(2-hydroxy)-n- hexadecyl]-spermine, 3.8 g (0.03016 moles) of oxaUc acid dihydrate and 50 ml of water was reacted analogously to Example 13 (duration of reaction: 18 hours). The title compound obtained decomposes at 200-205°, [α] D 20 = -7.4 ± 1.7° (c = 0.5% in H 2 0). The starting compound was produced as foUows: a) N^^.N^-tri-BOC-^-rrRV^-hydroxyVn-hexadecyll-spermine A mixture of 7.04 g (0.014 moles) of N 1 ,N 9 ,N 12 -tri-BOC-sρermine, 4.06 g (0.0169 moles) of (R)- 1,2-hexadecene oxide (Nippon Mining Company, Ltd.) and 30 ml of ethanol was stirred for 15 hours at 80° and subsequently concentrated by evaporation under vacuum. After purifying the residue by flash chromatography on siUca gel, using methylene chloride and a methylene chloride/methanol mixture (19:1), the title compound was obtained in the form of an oU, R f : 0.52 (solvent as in example 3a). Example 23: N 4 -(2-hydroxyethyl)-speπnidine trioxalate A mixture of 2.73 g (0.007 moles) of N 1 ,N 8 -di-BOC-N 4 -(2-hydroxyethyl)- spermidine, 2.65 g (0.021 moles) of oxaUc acid dihydrate, 10 ml of ethanol and 30 ml of water was stirred for 4.5 hours at 90°. The reaction mixture which was still warm was mixed with ethanol (untU sUght turbidity occurs) and was then cooled to 0°, whereby the title compound results in crystalline form, m.p. 153-156° (decomp.). The starting compound was produced as foUows: a) N 1 .N 8 -di-BOC-N 4 -r2-hydroxyethyD-spermidine The title compound was obtained in the form of an oU analogously to example 14a, from 6.91 g (0.02 moles) of N 1 ,N 8 -di-BOC-spermidine and 3.2 g (0.0726 moles) of ethylene oxide, after purifying the c de product on siUca gel using methylene chloride/methanol mixtures (19:1 or 9:1 or 4:1). Rf: 0.76 (solvent as in example la). Example 24: N 4 -(2-hydroxy)-n-hexadecyl]-spermidine-tri(toluene-4- sulfonate) A mixture of 6.21 g (0.0106 moles) of N 1 ,N 8 -di-BOC-N 4 -[(2-hydroxy)-n- hexadecyl]-spermidine, 6.05 g (0.0318 moles) of toluene-4-suU nic acid monohydrate and 30 ml of water was stirred for 2 hours at 75°. After purification of the reaction mixture by chromatography on AmberUte XAD 1180 absorber resin [eluant: water and water/isopropanol (4:1 or 3:2)] and subsequent lyophiUzation of the product-containing fractions, the title compound was obtained as the lyophiUzate with a water content of 2.2%, Rf: 0.26 (solvent as in example 1). The starting compound was produced as foUows: a) N 1 .N 8 -di-BOC-N 4 -[(2-hydroxy)-n-hexadecyl]-spermidine 10.61 g (0.0375 moles) of 1,2-hexadecene oxide (85%) were added to a solution of 8.64 g (0.025 moles) of N l ,N 8 -di-BOC-spermidine in 100 ml of ethanol. The reaction mixture was boUed under reflux for 15 hours, a further 1.7 g (0.006 moles) of 1,2-hexadecene oxide were added, the mixture was boUed under reflux for a further 7 hours and then concentrated by evaporation under vacuum. Purification of the crude product was effected by flash chromatography on silica gel, using ethyl acetate/hexane mixtures (1:2 or 1:1) and using ethyl acetate. The title compound was obtained in the form of an oU, R f : 0.85 (solvent as in example la). Example 25: N 4 -[(2-hydroxy)-n-hexadecyl]-norspermidine-tri(toluene-4- sulfonate) The title compound was obtained as the lyophilizate with a water content of 1.4%, analogously to example 24, from 5.72 g (0.01 moles) of N\N -di-BOC- N 4 -[(2-hydroxy)-n-hexadecyl]-norspermidine and 5.71 g (0.03 moles) of toluene-4- sulfonic acid monohydrate, R f : 0.24 (eluant as in example 1). The starting compound was produced as foUows: a) N 1 .N 7 -di-BOC-N 4 - 2-hydroxyVn-hexadecyll-norspermidine 6.56 g (0.0232 moles) of 1,2-hexadecene oxide (85%) were added to a solution of 6.4 g (0.0193 moles) of N\N 7 -di-BOC-norspermidine (Hansen et al, Synthesis 1982:404) in 75 ml of ethanol, and the reaction mixture was boUed under reflux for 17.5 hours. After adding a further 2.55 g (0.009 moles) of 1,2- hexadecene oxide (85%), the reaction mixture was again boned under reflux for 22 hours and then worked up analogously to example 24a. The title compound was obtained in the form of an oU, R f : 0.79 (solvent as in example la). Example 26: N 4 -[(2-hydroxy)-n-decyl]-norspermidine trioxalate The title compound was obtained analogously to example 13, from 3.2 g (0.00656 moles) of N N 7 -ώ-BOC-N 4 -[(2-hydroxy)-n-decyl]-norspermidine, 2.48 g (0.0197 moles) of oxaUc acid dihydrate and 25 ml of water. M.p. 174-179° (decomp.). The starting compound was produced as foUows: a) N 1 .N 7 -di-BOC-N 4 -[( ' 2-hydroxyVn-decyll-norsρermidine The title compound was obtained in the form of an oU analogously to example 22a, from 2.49 g (0.0075 moles) of N N'-di-BOC-norspermidine, 1.47 g (0.0094 moles) of 1,2-decene oxide and 25 ml of ethanol. After a short time, the compound soUdifies into crystalUne form, m.p. 52-54°. Example 27: N -[(2-hydroxy)-n-decyl]-spermidine-trioxalate A mixture of 3.19 g (0.00636 moles) of N 1 ,N s -di-BOC-N 4 -[(2-hydroxy)-n- decylj-spermidine, 2.405 g (0.01908 moles) of oxaUc acid dihydrate and 25 ml of water was boUed under reflux for 15 hours and subsequently concentrated by evaporation under vacuum. After crystallisation of the residue from acetone, the title compound was obtained with a water content of 1.9%. M.p. 170-173° (decomp.). The starting compound was produced as foUows: a) N 1 .N 8 -di-BOC-N 4 -rr2-hvdroxy)-n-decyll-spermidine The title compound was obtained in the form of an oU, analogously to example 22a, from 2.59 g (0.0075 moles) of N\N 8 -di-BOC-spermidine, 1.47 g (0.0094 moles) of 1,2-decene oxide and 25 ml of ethanol. R f : 0.50 (solvent as in example 3 a). Example 28: N j,N 9 -bis[(S)-(2-hydroxy)-n-decyl]-spermine tetraoxalate A mixture of 2.72 g (0.0038 moles) of N 1 ,N 1 -di-BOC-N 4 ,N 9 -bis[(S)-(2- hydroxy)-n-decyl]-spermine, 1.916 g (0.0152 moles) of oxaUc acid dihydrate and 30 ml of water was boUed under reflux for 15 hours. Acetone was added to the reaction mixture whUst it was still hot (and untU sUght turbidity occured), and the mixture was then slowly cooled to 0°, whereby the title compound precipitated in crystalline form. After filtration, washing the crystallizate with acetone and drying under a high vacuum, the title compound was obtained, m.p. 175-177° (decomp.), [α] D 20 = +13.1° ± 0.7° (c = 1.47%, H 2 0). The starting compound was produced as foUows: a) N 1 .N 12 -di-BOC-N 4 .N 9 -bisr(SV(2-hvdroxyVn-decyll-spermine A mixture of 2.013 g (0.005 moles) of N 1 ,N 12 -di-BOC-spermine, 2.34 g (0.015 moles) of (S)- 1,2-decene oxide and 20 ml of ethanol was boUed under reflux for 15 hours and subsequently concentrated by evaporation under vacuum. After purification of the residue by flash chromatography on silica gel, using methylene chloride/methanol mixtures (99:1 or 49:1 or 19:1 or 9:1), the title compound was obtained in the form of an oU, R f : 0.25 (solvent as in example 3a), [α] D 20 = +52.84 (c = 1.552%, hexane). Example 29: N ,N 9 -bis[(R)-(2-hydroxy)-n-decyl]-spermine tetraoxalate The title compound was obtained analogously to example 28, from 2.72 g (0.0038 moles) of N 1 ,N 12 -di-BOC-N 4 ,N 9 -bis[(R)-(2-hydroxy)-n-decyl]-spermine and 1.916 g (0.0152 moles) of oxaUc acid dihydrate. M.p. 175-177° (decomp.), [α] D 20 = -14.1° ± 0.7° (c = 1.43%, H 2 0). The starting compound was produced as foUows: a) N 1 .N 12 -di-BOC-N .N 9 -bisr(RVr2-hydroxyVn-decyn-spermine The title compound was obtained in the form of an oU, analogously to example 28a, from 2.013 g (0.005 moles) of N\N 12 -di-BOC-spermine and 2.34 g (0.015 moles) of (R)- 1,2-decene oxide, Rf: 0.25 (solvent as in example 3a), [α] D 20 = - 52.84° (c = 1.268%, hexane). Example 30: N 1 ,N 8 -bis(3-aminopropyl)-N 1 -[(2-hydroxy)-n-hexadecyl]-l,8- diamino-octane tetraoxalate The title compound was obtained analogously to example 13, but with a reaction time of 20 hours, from 2.84 g (0.00355 moles) of N',N 8 -bis(3-BOC- ammopropyl)-N 1 -BOC-N 8 -[(2-hydroxy)-n-hexadecyl]-l,8-diamino-octane, 1.79 g (0.0142 moles) of oxaUc acid dihydrate and 30 ml of water. M.p. 165-170° (decomp.). The starting compound was produced as foUows: a) N 1 .N 8 -bisr3-BOC-aminopropylVN 1 -BOC-N 8 -rr2-hvdroxy)-n-hexadecyn- 1.8-diamino-octane 4.8 g (0.00859 moles) of N 1 ,N 8 -bis(3-BOC-aminoρropyl)-N 1 -BOC-l,8- diamino-octane and 2.91 g (0.0103 moles) of 1,2-hexadecene oxide (85%) in 30 ml of ethanol were reacted analogously to example 21a (duration of reaction 16 hours). The title compound which was purified by flash chromatography on siUca gel, using methylene chloride and a methylene chloride/methanol mixture (20:1) was obtained in the form of an oU, R f : 0.60 (solvent as in example 3 a). b) N 1 .N 8 -bisf3-BOC-aminopropylVN 1 -BOC-l .8-diamino-octane and N 1 ,N 8 -bisf 3-BOC-aminopropyD- 1.8-diamino-octane A solution of 36.94 g (0.15 moles) of 2-(BOC-oxyimino)-2-phenylacetonitrUe in 120 ml of THF was added dropwise whUst stirring, over the course of 1.5 hours, and under a nitrogen atmosphere, to a solution, cooled to 0-5°, of 15.51 g (0.06 moles) of N 1 ,N 8 -bis(3-aminopropyl)-l, 8-diamino-octane [see Pestic. Sci. , 485-490 (1973)] in 100 ml of THF. The reaction mixture was stirred for a further 16 hours at room temperature, then concentrated by evaporation under vacuum, and the residue was separated by flash chromatography on sUica gel, using methylene chloride/methanol mixtures ( 100: 1 or 50: 1 or 20: 1 or 10: 1 ) and mixtures of methylene chloride/methanol/30% aqueous ammonia solution (90:10:0.5 or 90:15:0.5 or 40:10:1). The foUowing were thereby obtained: the first title compound, N 1 ,N 8 -bis(3-BOC-aminopropyl)-N 1 -BOC-l, 8-diamino-octane, in the form of an oU, R f : 0.81 (solvent as in example la), as weU as the second compound, N 1 ,N 8 -bis(3-BOC-aminopropyl)-l, 8-diamino-octane, m.p. 67-70°, R f : 0.26 (solvent as in example la). Example 31: N 1 ,N 8 -bis(3-aminopropyl)-N 1 -[(R)-(2-hydroxy)-n-hexadecyl]- 1,8-diamino-octane tetraoxalate The title compound was obtained analogously to example 13, but maintaining the reaction for 21 hours, from 3.71 g (0.00464 moles) of N 1 ,N 8 -bis(3- BOC-am opropyl)-N 1 -BOC-N 8 -[(R)-(2-hydroxy)-n-hexadecyl]-l,8-diamino- octane, 2.34 g (0.01856 moles) of oxaUc acid dihydrate and 35 ml of water. M.p. 165-170° (decomp.), [α] D 20 = -7.2° ± 1.6° (c = 0.5%, H 2 0). The starting compound was produced as foUows: a) N'.N 8 -bisr3-BOC-aminopropylVN 1 -BOC-N 8 -rfR f2-hvdroxyVn- hexadecyll-1.8-diamino-octane The title compound was obtained in the form of an oU, analogously to example 30a, from 5 g (0.00895 moles) of N 1 ,N 8 -bis(3-BOC-aminopropyl)-N 1 - BOC-1, 8-diamino-octane (example 30b), 2.58 g (0.01073 moles) of (R)-l,2- hexadecene oxide and 30 ml of ethanol. R f : 0.60 (solvent as in example 3a). Example 32: N 1 ,N 12 -bis(3-aminopropyI)-N 1 ,N 12 -bis[(2-hydroxy)-n- hexadecyl]-l,12-diamino-dodecane tetraoxalate The title compound was obtained analogously to example 13, but maintaining the reaction for 40 hours, from 1.3 g (0.001305 moles) of N'.N 12 - bis(3-BOC-ammopropyl)-N N 12 -bis[(2-hydroxy)-n-hexadecyl]-l,12-diamino- dodecane, 0.66 g (0.00523 moles) of oxaUc acid dihydrate and 20 ml of water. M.p. 115-118°. The starting compound was produced as foUows: a) N 1 .N 12 -bis(3-BOC-aminopropy -N 1 .N 12 -bisr(2-hydroxyVn-hexadecyn- 1.12-diamino-dodecane 1.1 g (0.002137 moles) of N 1 ,N 12 -bis(3-BOC-aminopropyl)-l, 12-diamino- dodecane and 1.45 g (0.00513 moles) of 1,2-hexadecene oxide (85%) in 25 ml of ethanol were reacted analogously to example 15a (duration of reaction: 18 hours). The title compound which was purified by flash chromatography on siUca gel, using methylene chloride/methanol mixtures (50:1 or 25:1 or 10:1) was obtained in the form of an oU, Rf: 0.91 (solvent as in example la). b) N^N^-bisfS-BOC-aminopropylVN'-BOC-l.12-diamino-dodecane and N\N I2 -bisf 3-BOC-aminopropylV 1.12-diamino-dodecane 36.1 ml (0.195 moles) of a 5.4 molar methanoUc solution of sodium methylate was added whUst stirring at room temperature and under a nitrogen atmosphere to a suspension of 23.9 g (0.0519 moles) of l,12-bis(3-aminopropyl)- 1,12-diamino-dodecane-tetrahydrochloride [J. Med. Chem. 7, 710 (1964)] in 130 ml of THF. After stirring for 20 minutes, the reaction mixture was cooled to 0°, and over the course of 1 hour, was mixed with a solution of 38.39 g (0.1559 moles) of 2-(BOC-oxyimino)-2-phenylacetonitrde in 130 ml of THF. Stirring continued for 15 hours at room temperature, the solution was filtered and the filtrate was concentrated by evaporation under vacuum. The residue was separated by flash chromatography on silica gel, using methylene chloride/methanol mixtures (50:1 or 25:1 or 16:1 or 10:1) and mixtures of methylene chloride/methanol/30% aqueous ammonia solution (90:10:0.5 or 90:15:0.5 or 40:10:1). The foUowing were thereby obtained: the first title compound, N 1 ,N 12 -bis(3-BOC-aminopropyl)- N^BOC-l, 12-diamino-dodecane, in the form of an oU, R f : 0.85 (solvent as in example la), as weU as the second title compound, N 1 ,N 12 -bis(3-BOC- aminopropyl)-l, 12-diamino-dodecane, m.p. 77-80°, R f : 0.48 (solvent as in example la). Example 33: N 1 ,N 4 -bis(3-aminopropyl)-N 1 ,N 4 -bis[(2-hydroxy)-n-decyl]-l,4- diamino-trans-2-butene-trioxalate A mixture of 1.65 g (0.002314 moles) of N 1 ,N 4 -bis(3-BOC-aminopropyl)- N 1 ,N 4 -bis[(2-hydroxy)-n-decyl]-l,4-diamino-trans-2-butene, 0.875 g (0.00694 moles) of oxaUc acid dihydrate and 15 ml of water was boUed under reflux for 16 hours and then concentrated by evaporation under vacuum. After crystallisation of the residue from methanol, the title compound was obtained with a water content of 3.5%, m.p. 163-165° (decomp.). The starting compound was produced as foUows: a) N 1 .N 4 -bis(3-BOC-aminopropyl -N 1 .N 4 -bisrr2-hvdroxyVn-decyn-L4- diamino-trans-2-butene The title compound was obtained in the form of an oU, analogously to example 1 la, from 2 g (0.005 moles) of N 1 ,N 4 -bis(3-BOC-aminopropyl)-l,4- diamino-trans-2-butene (example lib), 2.34 g (0.015 moles) of 1,2-decene oxide and 20 ml of ethanol (duration of reaction: 15 hours), using methylene chloride and a methylene chloride/methanol mixture (19: 1) for the flash chromatography. R f : 0.49 (solvent as in example 3a). Example 34: N 1 ,N 1 -bis(3-aminopropyl)-N 1 ,N 12 -bis[(2-hydroxy)-n- tetradecyl]-l,12-diamino-dodecane tetraoxalate A solution of 0.45 g (0.00357 moles) of oxaUc acid dihydrate in 20 ml of acetonitrUe was added whUst stkring to a solution of 0.66 g (0.000893 moles) of N\N 12 -bis(3-ammopropyl)-N\N 12 -bis[(2-hydroxy)-n-tetradecyl]-l,12-diarrιino- dodecane in 20 ml of methanol. The mixture was cooled to 0°, filtered, the residue washed with acetonitrUe and dried under a high vacuum. The title compound was thus obtained, m.p. 87-89°. The starting compound was produced as foUows: a) N 1 .N^-bisG-aminopropylVN 1 ,N 12 -bisrf 2-hydroxyVn-tetradecyll- 1.12- diamino-dodecane 0.81 g (0.0011 moles) of N 1 ,N 12 -bis(2-cyanoethyl)-N 1 ,N 12 -bis[(2-hydroxy)- n-tetradecyl]-l, 12-diamino-dodecane were dissolved in 10 ml of an 11% solution of ammonia in ethanol, mixed with 0.4 g of Raney nickel and hydrogenated untU the hydrogen uptake has ended. After filtering, concentrating the filtrate by evaporation under vacuum, and purifying the residue by flash chromatography on silica gel, using methylene chloride/methanol mixtures (40: 1 or 10: 1) and mixtures of methylene chloride/methanol/30% aqueous ammonia solution (90:10:0.5 or 40: 10: 1.5), the title compound was obtained in the form of an oU, Rf: 0.34 (solvent as in example la), which graduaUy soUdified into crystalline form. b) N 1 .N 12 -bis(2-cyanoethylVN 1 .N 12 -bisr(2-hydroxyVn-tetradecyll-l.12- diamino-dodecane 11.99 g (0.048 moles) of 1 ,2-tetradecene oxide (85%) were added to a solution of 6.13 g (0.02 moles) of N 1 ,N 12 -bis(2-cyanoethyl)-l, 12-diamino- dodecane [J. Med. Chem. 7, 710 (1964)] in 60 ml of ethanol. The reaction mixture was heated under reflux for 40 hours, a further 2.54 g (0.01016 moles) of tetradecene oxide (85%) were added, the reaction mixture was boUed under reflux for a further 6 hours, and then concentrated by evaporation under vacuum. Purification of the crude product was by flash chromatography on siUca gel, using methylene chloride and methylene chloride/methanol mixtures (40:1 or 20:1). After concentrating the product-containing fractions by evaporation under vacuum and crystallizing the residue from acetonitrUe, the title compound was obtained, m.p. 37-38°. Example 35: Preparation of core complexes of plasmid nucleic acid with substituted aminoethanols and their biological activity. Preparation of core complexes of nucleic acid can be performed using substituted aminoethanols either with or without long chain hydrocarbon (ahphatic) substitutients. Substituted aminoethanols lacking long chain hydrocarbon (ahphatic) substitutients were used to compact plasmid DNA into a coUoidal dispersion in water. The size and zeta potential of the coUoidal dispersions prepared were determined at different charge ratios for added cation (amine) to anion (DNA phosphate) and are shown in Table 1 and Figure 4. The coUoidal dispersions prepared permit compaction of the DNA into core complexes that are suitable for the invention. Substituted aminoethanols with long chain hydrocarbon (ahphatic) substitutients also were used to compact plasmid DNA into a coUoidal dispersion in water. In some cases these core complexes alone are sufficient to provide gene deUvery in ceU culture or when administered to animals. This effect is illustrated in results below (Table 2 and 3). Table 1. Particle size and Zeta Potential of Substituted Amino-Ethanol-DNA complexes The gene deUvery abiUty of substituted aminoethanols with long chain hydrocarbon (ahphatic) substitutients was studied by transfection of cultured ceUs and then in vivo by intravenous injection (Table 2 and 3). The substituted aminoethanols have two hydrophiUc polar heads connected with one hydrophobic body, which was named bihead Upids. Bihead Upids are proposed to form a monolayer membrane. Substituted aminoethanols (cationic compounds) were prepared as described in Examples 1-34. Their gene deUvery abUity was studied in vivo by intravenous injection (Table 1 and 2) using a standard method. The preparations were administered via taU vein injection to mice and gene expression determined after 5 hours. Female CD-I mice, 13-15 g, were purchased from Charles River Inc. Forty microgram of pCILuc complexed with GC Upids or GC hpid:Chol dispersion as indicated weight ratios. After 5 h, mice were sacrificed and organs were coUected. Organs were homogenized in 0.5 ml of lysis buffer and 20 μl of supernatant was used for luciferase assay. Luciferase activity was represented as a mean of relative Ught unit (RLU) of four mice. The Upids were either used alone or combined with cholesterol and complexed with a luciferase reporter gene plasmid by a standard procedure at a range of weight and charge ratios. For the in vivo screen, 40 μg of pCILuc was complexed with the formulation and injected into the mice. The relationship of structure and gene deUvery function also was studied. The number and the length of fat acid chains were found to impact their gene deUvery abiUty. If the Upids had only one chain, transfection activity was not observed, regardless of the length of the acid chains. If the length of two chains was shorter than C14, transfection activity also was not observed. If the Upid had one short chain (<C14) and one long chain (>C14), it could not dehver genes. However, with longer chains such C14 and C16, the Upids showed transfection activity not only in vitro as also in vivo. The in vitro transfection activity was even higher than that of commerciaUy avaUable Upid preparations, such as Lipofectamine7. When the length of carbon chain between two ammonium groups in the hydrophiUc polar head increased from C4 to C12, the conformation of Upids in water may change from that of a typical Upid with one head to a form with two heads at each end of the molecule. Accordingly, such Upids are referred to herein as bihead Upids and this is shown in Figure 3. Substituted aminoethanols CGP44015 and CGP47204, chemical structures shown in Figure 3.4, disperse in water to form very smaU homogenous miceUes with a diameter around 10-20 nm. They bind to plasmid DNA forming core complexes with a particle size dependent on the charge ratio of cationic compound to DNA. In this aspect they are representative of the substituted aminoethanol class of compounds giving smaU, relatively homogenous, and stable complexes with nucleic acids as Ulustrated with a different compound in Figure 4. When the charge ratio is more than 1, the particles are homogenous with diameter less than 100 nm. Their transfection activity increases with increasing charge ratio to 4. The optimal charge ratio in vitro is 4. The transfection activity decreased with further increase in charge ratio. The in vivo transfection activity and charge ratio relationship was simUar to that in vitro but the optimal charge ratio is 4-10 (Table 1 and 2). OveraU, the compounds with the same charged head groups showed good complexation with plasmid DNA and gene deUvery in vitro as weU as in vivo. The substituted aminoethanols tested here appear to have two hydrophiUc polar heads connected by one hydrophobic body (Figure 3) and are referred to as bihead Upids. Since two hydrophiUc heads at either side could face an aqueous solution, these compounds could form a monolayer in water instead of a bUayer formed by Upids with one head group (Figure 3.1). These results show good gene transfer abiUty. Among the preferred Upids, CGP44015A and CGP47204A form core complexes that exhibit expression in vivo. CGP44015 and CGP47204 have the same positive charges in both heads. The bihead Upids show high gene transfer abiUty in vitro as weU as in vivo. Table 2 Table 3 Table 3 continued Example 36: Preparation of core complexes of plasmid nucleic acid with cationic lipids Cationic Upids GC-001, GC-003, GC-016, GC-021, GC-025, GC-026, GC-029, GC-030, GC-033, GC-034, GC-035, GC-38, GC-039, and GC-071 were purchased from Promega Biosciences, San Luis Obispo, CA [formerly JBL Scientific, Inc/Genta]. Other materials and methods were performed as described in Example 35. The measurement of luciferase expression in selected organs is summaried in Table 3. AU compounds were evaluated for in vivo activity. Two critical factors were examined, formulation with or without cholesterol and the ratio of cationic Upid to DNA. Cholesterol was tested at 1: 1 mole ratio of Upidrchol. The studies were performed with a dose of 40 μg of pCILuc complexed with cationic Upid or hpid.Chol (1:1 mole ratio) injected i.v. into CD-I mice and then luciferase activity in different organs determined 5 h later. The first evaluation included aU of 14 GC Upids at weight ratios of 2 and 10 (GC Upid to DNA). It was performed by four separated experiments. Each time cationic Uposome DOTAP:Chol was used as a standard control. Results were shown in Table 4. Many GC Upid formulations showed luciferase activity more than 2000 RLU/20 μl lysate in spleen and Uver. Measurements were repeated with Upids GC-030, GC-034 and GC-029 at wider weight ratios than the first experiment. The transfection procedure was the same as that for results shown in Table 3. Luciferase activity is represented as a mean of relative Ught unit (RLU) of four mice. WR means weight ratio of GC Upids to DNA. The results are shown in Table 5. The transfection activity was represented by luciferase activity RLU/organ. GC-030 showed high transfection activity at weight ratio 20. The transfection activity increased with the increased weight ratio (GC Upids to DNA). Inclusion of cholesterol can change the biodistribution of gene expression in the different organs examined. For example, GC-030 alone resulted in high luciferase activity in spleen and GC-030:Chol resulted in high luciferase activity in lung. However this fimction of cholesterol was not seen with GC-034. GC-030 showed high luciferase activity in spleen at weight ratio 20, in fact 36 fold higher than that of the DOTAP.Chol standard. Likewise, GC-030: Choi showed high luciferase activity in lung, about 5 fold higher than that of DOTAP:Chol. These results show that GC Upids form good core complexes for gene deUvery vectors. Table 4. Evaluation of GC lipids in mice via IV injection. RLU/20 μl Ivsate WR spleen liver kidney heart lung GC-001 2 38 35 39 36 51 GC-001 10 329 38 36 39 101 GC-001 /chol 2 46 39 33 36 57 GC-001/chol 10 40 34 34 34 40 GC-003 2 36 33 38 37 37 GC-003 10 65 73 40 39 69 GC-003/chol 2 323 39 36 34 90 GC-003/chol 10 46 37 34 40 54 GC-021 2 43 36 34 34 54 GC-021 10 37 32 35 39 40 GC-021/chol 2 78 81 46 44 64 GC-021 /chol 10 62 60 57 58 120 DOTAP/chol 8.5 2,756 2,721 360 2,134 150,682 RLU/20 ul I lysate WR spleen liver kidney heart lung GC-016 2 4f1 38 41 4 ΔFs GC-016 10 230 95 40 40 67 GC-016/ohol 2 38 39 40 45 44 GC-016/c ol 10 111 1 ,007 52 43 449 GC-026 2 40 39 41 42 40 GC-026 10 0 0 0 0 0 GC-026/chol 2 47 46 50 54 49 GC-026/chol 10 57 52 88 1,315 50 GC-030 2 3,692 70 51 48 88 GC-030 10 5,305 1,093 105 67 1,396 GC-030/chol 2 61 51 51 47 48 GC-030/chol 10 1,330 3,065 246 60 574 GC-039 2 288 48 45 50 52 GC-039 10 845 212 54 45 753 GC-039/c o) 2 49 47 48 46 49 GC-039/choI 10 84 376 4,503 78 173 DOTAPtc ol 8.5 549 153 93 9,725 8,163 (Continuation of Table 4) RLU/20 ul lysate WR spleen liver kidney heart lung GC-025 2 46 38 25 33 40 GC-025 10 32 27 28 27 30 GC-025/chol 2 26 26 28 27 26 GC-025/chol 10 65 66 26 28 33 GC-033 2 27 29 27 31 36 GC-033 10 50 46 41 40 42 GC-033/chol 2 45 46 49 46 45 GC-033/chol 10 50 86 47 46 47 GC-035 2 70 57 46 54 57 GC-035 10 54 50 54 51 54 GC-035/chol 2 82 72 47 52 51 GC-035/chol 10 91 84 46 43 329 DOTAP/chol 8.5 1011 331 78 1412 45457 RLU/20 ul lysate WR spleen liver kidney heart lung GC-029 2 31 31 34 42 41 GC-029 10 196 65 42 34 72 GC-029/chol 2 31 29 31 39 34 GC-029/chol 10 1,512 104 33 33 53 GC-034 2 7,769 480 36 45 137 GC-034 10 2,386 597 53 103 90 GC-034/chol 2 63 80 59 62 63 GC-034/chol 10 1,645 1 ,597 58 70 267 GC-038 2 61 59 60 101 142 GC-038 10 160 93 58 57 63 GC-038/chol 2 56 55 75 69 268 GC-038/chol 10 783 132 130 140 1 ,210 GC-071 2 61 59 58 60 56 GC-071 10 286 531 67 61 73 GC-071/chol 2 95 60 59 60 63 GC-071 /chol 10 263 476 64 60 187 DOTAP/chol 8.5 909 1,084 281 603 101,852 Table 5. Evaluation of selected GC lipids i n mice. Liposome WR spleen liver kidney heart lung GC-030 1 23,308 3,642 1,392 1,675 3,308 GC-030 2 73,442 3,417 1,458 1,367 1,600 GC-030 6 38,058 1,550 792 817 8,808 GC-030 10 446,650 114,425 1,367 3,450 35,117 GC-030 20 2,479,217 1,003,125 17,583 4,783 689,475 GC-030/chol 2 202,158 5,283 1 ,167 1 ,058 3,983 GC-030/chol 10 593,158 141,383 5,808 7,058 1,965,650 GC-030/chol 15 581,875 452,575 10,892 54,642 4,353,292 GC-030/chol 20 820,250 894,608 38,233 428,575 17,411,233 GC-034 0.5 8,750 1,792 1 ,300 1 ,425 3,567 GC-034 1 10,458 2,758 1,283 1,333 4,492 GC-034 2 29,167 3,317 1,175 1 ,158 2,367 GC-034 6 449,583 10,533 1,567 1,467 6,233 GC-034 10 505,975 63,942 1 ,750 1,642 9,775 GC-034/chol 2 7,392 4,017 1,500 1,425 2,575 GC-034/chol 10 58,933 4,975 1 ,558 1 ,483 13,592 GC-034/chol 15 39,208 4,775 1,383 1,450 5,958 GC-034/chol 20 37,542 7,475 1 ,492 1 ,317 9,892 DOTAP/chol 8.5 68,908 68,025 9,000 53,342 3,767,050 Liposome WR spleen liver kidney Heart lung GC-029 2 908 825 1,000 933 967 GC-029 10 1,992 1,408 808 858 1,017 GC-029/c ol 2 842 817 842 908 875 GC-029/chol 6 942 942 908 950 1,125 GC-029/chol 10 867 958 933 950 3,308 GC-029/chol 18 4,250 3,875 950 858 2,392 DOTAP/chol 8.5 9,267 11,350 3,650 8,042 1,114,275 Example 37: Preparation of linear PEI Linear PEI of MW of 22 kDa was prepared from poIyethyloxazoUne polymer (PEOZ) by acid hydrolysis to the polyamine. The PEOZ was prepared by polymerization using methyl tosylate and 500 equivalents of 2-ethyl-2-oxazoUne foUowing essentiaUy the same previously reported procedure by ZaUpsky et al. J. Pharm. Set; 85: 133-137 (1996). It was necessary to use 2-ethyl-2-oxazoline instead of 2-methyl-2-oxazoUne as the latter precipitated at MW 16,200 in acetonitrile. Also longer reaction times were needed. Preparation of Poly(2-ethyl-2-oxazoline) of MW 49,500 kDa. Polymerization reaction was conducted in a screw-cap tube that was dried under vacuo wh e heated prior to use. The tube was charged with 5.05 ml of 2- ethyl-2-oxazoline that was freshly distiUed over KOH and 5 ml of dry acetonitrUe. 491 mg of freshly distiUed methyl tosylate was dissolved in 10.55ml of dry acetonitrUe and 0.4 ml of this solution was transferred to the tube containing the monomer. After this transfer the tube was purged with argon, sealed and left stirring in an oU bath at 80° C for 112 h. After cooling to room temperature 2 ml of a methanoUc solution of KOH (0.5M) was added to the polymerization mixture foUowed by stirring at 25 ° C for 5 h. 0.2 ml of glacial acetic acid was added and the mixture concentrated to soUd, redissolved in 50 ml of water and placed in 3500 molecular weight cutoff Spectral Por dialysis membranes (Spectrum, Los Angeles,CA). Dialysis was against 50 mM NaCI (1 x 4L) and water (3 x 4L). The content of the dialysis bags were lyophilized and further dried under vacuo to give 4.51g of white solid (91%). Mass spectral analyses (MALDI-TOF) showed cluster at m/z 45,000-65,000 and centered at m/z 52,395 (expected m/z 49,500). 1 HNMR ( 400 MHz CDCla) δ 1.11-1.12 (m, CH^CH 2 C=O), 2.31-2.41 (m, CH 3 CH 2 C=0), 3.46 (m, CH 2 N) 13 C NMR (100 MHz CDC1 3 ) 5 9.2 (bs, CH 3 CH 2 C=O), 25.82 (s, CH 3 CH 2 C=O), 43.54-47.27 (m, CH 2 N), 173.79-174.40 (m, C=0) Preparation of Linear Polyethylenimine of MW 22 kDa. The acid hydrolsis was conducted in a screw-cap tube. The tube was charged with O.lg of Poly(2-ethyl-2-oxazoline) of MW 49,500 kDa and 10 ml of 3.3 M aqueous HCl. The solution was degassed, purged with argon, sealed and left stirring in an oU bath at 100° C for 65 h. Higher acid concentrations lead to precipitation during hydrolysis at 100° C. After cooling the mixture is concentrated to a soUd, redissolved in water and again concentrated to a soUd. Redissolved in 1 ml of water and pH was adjusted to 12-13 upon the addition of 2.5 M aqueous NaOH. The precipitate of linear polyethylenimine was coUected by centrifugation and further washed with water (2 x 1ml) to give 43 mg of white soUd (100%). Η NMR (360 MHz, CD 3 OD) δ 2.73 (br, CH 2 N) Example 38 Streams of salmon sperm DNA, at a concentration of 50 μg/ml and of polyethyleneimine were fed into an HPLC static mixer which included three 50 μl cartridges in tandem. In the making of each preparation of particles, each stream was fed into the mixer at the same flow rate, and such flow rate was maintained as the resulting combined stream of DNA and polymer flowed through the cartridges. Flow rates were from 250 μl/min. to 5,000 μl/min. The particle sizes for each preparation made at a given flow rate are given in Table 6 below. Table 6 0 Particle Size Example 39 The procedure of Example 38 was repeated, except that the streams of DNA and polyethyleneimine were fed into an HPLC mixer containing three 150 μl 5 cartridges in tandem and flow rates varied from 500 μl/min. to 7,000 μl/min. The particle sizes for each preparation made at a given flow rate are given in Table 7 below. Table 7 Particle Size The results of Examples 38 and 39 show that particle size can be adjusted by changing the size of the mixing cartridges and by changing the flow rate. Thus, 5 one can choose conditions which wiU provide particles of a desired size and homogeneity. Example 40 The procedure of Example 38 was repeated, except that sodium chloride in 10 varying concentrations was added to the DNA and polymer after the mixing of the DNA and polymer. The mean particle sizes for each preparation made at a given concentration of salt are given in Table 8 below. Table 8 Particle Size The above results show that particle size can be controUed with the addition of salt, and that such particles remain uniform in size. Example 41 The procedure of Example 38 was repeated, except that the DNA concentration was 100 μg/ml, and flow rates were varied from 500 μl/min. to 4,000 μl/min. The particle sizes for each preparation made at a given flow rate are given in Table 9 below. Table 9 10 Particle Size The above results, when compared with those of Example 38, show that particle size can be changed by changing the concentration of DNA. Example 42 15 The procedure of Example 38 was repeated, except that the mixer contained one 250 μl cartridge, and Tween 80 detergent in an amount of 0.25% by volume was added to the DNA stream prior to mixing with the polyethyleneimine stream and flow rates were varied from 210 μl/min. to 8,400 μl/min. for the DNA and Tween 80 stream. When the DNA and Tween 80 stream and the polymer 20 stream were fed initiaUy into the mixer, the flow rate of the DNA and Tween 80 stream was 1.4 times that of the polymer stream. When the combined stream of DNA and Tween 80 and polymer traveled through the cartridge, the flow rate of the combined stream was the average of the initial flow rates of the DNA and Tween 80 stream and the polymer stream. For example, if the DNA and Tween 80 stream had an initial flow rate of 4,900 μl/min. and the polymer stream had a flow rate of 3,500 μl/min., the flow rate of the combined stream through the cartridge was 4,200 μl/min. The particle sizes for each preparation made at a given flow rate are given in Table 10 below. Table 10 Particle Size * Initial flow rate of DNA and Tween 80 stream. The above preparations include miceUs which in general have a size of from 10 about 10 nm to about 20 nm. The sizes of these miceUes were counted into the determinations of mean particle sizes given above. Such miceUes were are formed from the Tween 80 detergent, and could be removed by ultrafiltration from the preparations prior to the use or storage thereof. Thus, in another experiment, a preparation of particles and miceUs, 15 prepared as hereinabove described, wherein the initial flow rate of the DNA/Tween stream was 4,900 μl/min. and the initial flow rate of the polymer stream was 3,500 μl/min., and having a concentration of DNA of 20.8 μg/ml, had the foUowing mean particle size and size distribution. Unimodal mean - 42.6 nm 20 Std. dev. unimodal - 19.6 Std. dev. % - 46 SDP mean 75.5 Std. dev. SDP - 32.6 Std. dev. % 43 This preparation was filtered through a 0.2 μ filter, foUowed by 5 concentration by ultrafiltration through an Amicon polysulfone (molecular weight 500 Kda) membrane at a flow rate of 300 μl/min. with isometric structure (Millipore Corporation, Bedford, MA). After the concentration and filtration, which provided for the removal of the miceUs, the preparation had a DNA concentration of 450 μg/ml. The preparation was stored for 7 days, and the mean 10 particle size and distribution was measured at the start of storage, 12 hrs., 2 days, 3 days, 7 days 16 days, and 43 days. The particle sizes are given in Table 11 below. Table 11 Particle Size 15 The above results show that a preparation of particles produced in accordance with the procedures described in this example, remains stable over time in that the size of the particles remains essentiaUy constant. Example 43 20 The procedure of Example 42 was repeated, except that the DNA and Tween 80 and polyethyleneimine were flowed through a 50 μl cartridge, foUowed by flowing through two 150 μl cartridges contained in the mixer, and the initial flow rates of the DNA and Tween 80 stream were varied from 250 ul/min. to 3,500 μl/min. The particle sizes for each preparation made at a given flow rate are given in Table 12 below. TABLE 12 Particle Size * Initial flow rate of DNA and Tween 80 stream which has a flow rate 1.4 times greater than that of the polymer stream. From the above table, the most desired conditions were selected which provided a homogeneous preparation. These conditions were appUed to produce three independent batches. 10 The above procedure then was repeated twice at the initial flow rate of 1,500 μl min. for the DNA and Tween 80 stream. The results of the original experiment (Experiment 38) at a flow rate of 1,500 μl/min. and the repeated experiments (Experiments 39 and 40) are given in Table 13 below. TABLE 13 15 PARTICLE SIZE The above results show that the method is reproducible in that, when one mixes aqueous solutions of DNA and polymer continuously at a constant charge ratio of polymer to DNA at constant flow rates, one obtains homogenous preparations of particles of DNA and a polymer consistently, wherein each preparation includes particles having simUar mean particle sizes. Thus, the method of the present invention is independent of the operator. Other methods, such as hand-mixing and pipetting, are dependent upon the skiU of the operator. The above procedure was repeated at a flow rate of 1,500 μl/min., except that such procedure was scaled up such that 20 ml of each stream was fed through the mixer. The mean particle size, as determined by the unimodal mean and the intensity mean, was as foUows: Unimodal mean 88.3nm Std. dev. unimodal 38.2 % Std. dev. 43 SDPmean 117nm Std. dev. SDP 37.3 % std. dev. 32 This preparation then was filtered through a 0.2 μ filter foUowed by concentration by ultrafiltration through an Amicon polysulfone (molecular weight 500 Kda) membrane at a flow rate of 300 μl/min. as described in Example 42, except that, after the concentration and filtration, the preparation had a DNA concentration of 250 μg/μl. The mean particle size, as determined by the unimodal mean and the intensity mean, was as foUows: Unimodal mean 102.9nm Std. dev. unimodal 37.6 % std. dev. 37 SDP mean 115.5nm Std. dev. SDP 23.9 % std. dev. 21 The preparation again was subjected to filtration through a 0.2μ filter, foUowed by concentration with an Amicon polysulfone (molecular weight 500 Kda) membrane at a flow rate of 300 μl/min., after which the preparation had a DNA concentration of 870 μg/μl. The mean particle size, as determined by the unimodal mean and the intensity mean, was as foUows: Unimodal mean 108.6nm Std. dev. unimodal 37.6 %std. dev. 35 SDP mean 117.5 nm Std. dev. SDP 25.2 % std. dev. 21 Thus, the above results show that ultrafiltration of the particle preparations provides a homogeneous dispersion of DNA and polymer particle. In addition, the abiUty to make such a preparation of homogenous particles is independent of batch size. Example 44: Preparation of core complexes with linear PEI and its biological activity Linear PEI was dissolved in deionized water to obtain a final concentration of 100 mM amine as determined by an ethidium bromide displacement assay. In this assay 1 mmol is defined as the amount of PEI amine required to completely neutralize 1 mmol of DNA phosphate. From a 2.72 mg/ml stock solution of plasmid DNA (pCIluc) 221 μl was combined with 110 μl of 45.46 % glucose solution and 597 μl of water. 72 μl of the PEI solution was added to the mixture and vortexed thoroughly for 20 sec, to prepare complexes that had a 4: 1 +/- ratio. Two hundred microUtres of the complex were injected into CD-I mice via the tail- vein. Each group consisting of 5 animals received the same dose. The mice were euthanized after 5h, their organs harvested, ground, lysed and assayed for luciferase expression as described previously. The results are shown in Figure 5. They show that the core complexes exhibit activity to provide gene transfer in vivo although this activity can be improved for some therapeutic appUcations by addition of other features of a layered coUoid vector. Example 45: Preparation of coated core complexes cationic lipid and PEG based fusogen surfactants and PEG-based steric surfactants and their biological activity Preparation of Cationic Lipid Dispersion: AU Upids of a formulation including surfactants were dissolved in an organic solvent such as cyclohexane and mixed together at the desired ratio and then lyophilized to dryness. For example, 45 mg DOTAP and 25 mg cholesterol, or 10 mg GC-030 and 4.74 mg cholesterol were used for DOTAP:Chol and GC- 030: Chol, respectively. Double distiUed water was added to the Upid cake to give a final concentration of 10 mg/ml of cationic Upid (cholesterol is a neutral Upid that is not counted for calculation of Upid dispersion concentration or later for charge ratio with DNA) and aUowed to hydrate at 70 C for 1 hr. The Upid dispersion was extruded through 100 nmpore carbonate membranes (Avanti Polar Lipids Inc) or vortexed for 1 min at room temperature. Preparation of Upoplexes: Forty microgram of pCILuc was dissolved in 100 μl of 10% glucose and mixed by hand with different amount of Upids dispersion dissolved in 100 μl distiUed H2O. The final concentration of Glucose is 5%. The mixing was performed by added the DNA solution to the Upid solution. The charge ratio of Upids to DNA in this mixture was indicated in the text. 200 μl of DNA/Upid complex solutions was injected into mouse taU vein. Each group had 3-5 mice. Five hours later, mice were sacrificed. Spleen, Uver, kidney, heart and lung were excised and placed in 2 ml centrifuge tubes (Purchased from Bio 101). After added 0.5 ml lysis buffer, organs were crushed by shaking in Fasprep FP120 (Purchased from Bio 101) for 40 sec. The homogenate was centrifuged at 14,000 rpm for 5 min in table centrifuge. The 20 μl of supernatant was used for luciferase assay. Luciferase activity was determined by using luciferase assay system kit from Promega. Transfection in vivo: The in vivo studies were performed by injection of 200 ul of DNA/Upid complex solutions by taU vein in either mouse or neonatal rats (3-10 days old). Each group had 5 animals. Five or 8 hours later, the blood was coUected by cardiac puncture, the animals sacrificed, and other organs (e.g. lungs, Uver, spleen, kidney, heart) excised surgicaUy. Serum samples were prepared by centrifugation of coagulated blood. Organ samples were prepared by addition of 1 ml lysis buffer and homogenization with Bio 101 Fasprep FP120 for 40 sec. The homogenate was assayed directly for reporter gene activity or centrifuged at 14000 rpm in microtubes for 10 min and the supernatant used for protein activity assay. The results are shown in Figure 7. They show that the core complexes exhibit activity to provide gene transfer in vivo, the results obtained with DOTAP:Chol without additive, that the activity can be improved by fusogenic additives, the results obtained with added Brij, Thesit, and Tween, and the activity can be inhibited by addition of steric coating additive, the results with Chol- PEG5000. Thus some features of a layered coUoid vector are illustrated. Example 46: Preparation of coated core complexes with fusogen peptide and their biological activity Materials: AU peptides were obtained from commercial peptide synthesis company (Genemed Synthesis Inc, South San Francisco, CA) with at least 85% purity. Peptide K14 contains the amino acid sequence of KKK KKK KKK K K KK. Peptide K14 Fuso contains fusogenic peptide derived from influenza hemagglutinin with the amino acid sequence of GLF GAI EGF IEN GWE GWI DGW YGC KCK KKK KKK KKK KKK K. Lipofectamine and Upofectin was purchased from BRL (Gaithersburg, MD). Method: Transfection: BL-6 ceUs were seeded to each weU of a 96 weU plate at 10000 ceUs/weU at one day earlier. 0.5ug of pCDuc2 DNA and different amount of peptide (ug) or Upofecting regent (ul) as indicated was added to 50ul of serum free medium separately. Then the peptide or Upofecting reagent-containing medium was added to the DNA containing medium. The mixture was incubated at room temperature for 30 min and then added to the ceU. After 3hr incubation, the transfection solution was removed and medium was exchanged to the semm containing one. Luciferase activity was measured at 24hr after the transfection with luciferase assay kit from Promega according to the recommended procedure. The results are shown in Figure 8. They show that the core complexes exhibit activity to provide gene transfer in vitro varies with core. The results obtained with K14 and the two commercial Upid reagents show that the cores formed by the two Upids give substantially greater expression than that formed by the K14. The results also show that the activity of the core formed by K14 can be improved by addition of a fusogenic peptide sequence to give a substantial increase in expression to paraUel that by the two Upids. Thus some features of a layered coUoid vector are illustrated. Example 47: Preparation of hydrazone Unkage and acid pH induced cleavage (Synthesis, cleavage assay methods, results) Preparation of l-Acetyl-2-paramethoxyphenylhydrazone To a stirred solution of 0.108g of acetic hydrazide in 0.2ml of methanol 0.33ml of anisaldehyde was slowly added. After the addition the reaction was stirred for a further 48h. 0.1ml of reaction mixture was taken and added to 0.4ml of water. 0.085ml aUquots were then purified using C8 reverse phase hplc (Vydac 300A, lOu, 250mm x 10mm) with solvent A as aqueous 0.025M sodium phosphate pH 7.5 and solvent B as methanol. Flow of 1ml per minute and gradient of 55% to 95% solvent B over 35 minutes was used. The product l-acetyl-2- paramethoxyphenylhydrazone was coUected from the peak eluting at 15 minutes into the gradient to give 0.020g of a white soUd. 1H NMR (400 MHz, DMSO-d6) showed the prescence of two isomers of product , anti- and syn-geometrical isomers of ratio 1: 1.69. Major isomer: δ 2.17 (s, CH 3 C=O), 3.79 (s, CH 3 O), 6.98 (d, J=8.8, Ar), 7.59 (d, J=8.6, Ar), 7.92 (s, ArCH=N), 11.105 (s, NHAc) Minor isomer: δ 1.92 (s, CH 3 C=O), 3.795 (s, CH 3 O), 6.99 (d, J=8.8, Ar), 7.61 (d, J=8.4, Ar), 8.08 (s, ArCH=N), 11.22 (s, NHAc) For the acid hydrolysis studies 0.35mg of anti- / syn-mixtures of l-acetyl-2- paramethoxyphenylhydrazone was dissolved in 2ml of 0.05M sodium citrate/potassium phosphate pH 5 containing 10% methanol. The mixture was immediately adjusted to pH 5 using NaOH and the reaction was kept at 370C. At time intervals 0.1ml was withdrawn and 0.3ml of 0.25 M of potassium phosphate pH 7.5 was added to raise the pH to 7.5. Injected onto C8 reverse phase hplc (Vydac 300A, lOu, 250mm x 10mm) with solvent A as aqueous 0.025M sodium phosphate pH 7.5 and solvent B as methanol. Flow of 1ml per minute and gradient of 55% to 95% solvent B over 35 minutes was used. Rate of hydrolysis was determined by the peak areas of the 4-methoxybenzaldehyde and l-acetyl-2- paramethoxyphenylhydrazone peaks. The above acid hydrolysis studies were performed in the same manner using buffers at pH 5.5 and 6.1. The results are shown in Figure 9. They show that the hydrazone linkage can be hydrolyzed at acidic pH and that the rate of cleavage depends on the chemical structure of the linkage. Thus some features of a layered coUoid vector where the vector changes physcial states due to exposure to acid conditions are Ulustrated. Some uses of the changes due to acidic conditions include loss of steric protective layers and induction of fusogenic activity. Example 48: Preparation of core complexes coated with ligand peptide and their biological activity Synthesis of K14-RGD and K14-SST Preparation of complexes including peptide Ugand conjugates and Ugand- mediated ceU binding and uptake Materials: K14RGD peptide containing the amino acid sequence: KKK KKK KKK KKK KKS CRG DC with at least 90% purity was synthesized at Alpha Diagnostic International (San Antonio, TX). Peptide K14SMT contains the amino acid sequence: KKK KKK KKK KKK KKA d-FCY d-WKT CT, and peptide K14MST contains the amino acid sequence KKK KKK KKK KKK KKA TDC RGE CF. Both SMT and MST peptides were synthesized at Genemed Synthesis Inc (CA, South San Francisco) and oxidized to make circularized peptide. The peptide was purified to 90% purity by the provider. CHO (Sst+) ceU line was obtained from Novartis Oncology (Dr.Friedrich Raulf). The ceU Une was selected to stable express human somatostatin receptor Sst2. Method: 20000 HUVEC ceUs were seeded to each weU of a 96 weU plate and cultured for 12hr before transfection. 0 or 2ug of K14RGD peptide was mixed with indicated amount of Lipofectin from 0. lul to 4ul in 50ul of serum free medium for 15 min. The mixture was added to 50ul serum free medium containing 0.5ug pCIluc2 DNA. The poly-Upoplex was incubated for 30min before added to the ceUs. The transfection solution was removed after 3hr and serum-containing medium was added to the ceUs. 10000 CHO (Sst2) ceUs were cultured in a semm-containing medium with 0.4mg/ml G418 for 12hr before transfection in each weU of a 96 weU plate. The medium was changed to a serum free medium before transfection. Peptide was added to the ceU at indicated amounts from lug to lOug/weU and incubated for 30min before 0.5ug pCIluc2 was added to the same medium to transfect the ceUs. Lipofectin at 4ul was used as the control. At 24hr, luciferase activity was measured with Promega luciferase assay kit according to the recommended procedure. Results: The results are shown in Figures 25 and 26. Figure 25 shows increased expression by addition of a peptide Ugand (K14RGD) to Upofectin core complexes. Figure 26 shows increased expression by addition of a peptide Ugand (Somatostatin or SMT) to polylysine core complexes which is not observed when a mutated somatostatin sequence (MST) is used. These figures demonstrate that the core complexes may exhibit activity to one extent or another but regardless the activity of the core can be improved by addition of a targeting Ugand to give a substantial increase in expression. Thus some features of a layered coUoid vector are Ulustrated. Example 49: Preparation of NLS moiety coupled to nucleic acid Several means can be used to couple an NLS moiety to nucleic acid some of which are Ulustrated in Figure 10A and include direct conjugation to the nucleic acid and indirect through another agent that binds the nucleic acid either in a sequence specific or sequence independent means. Agents required for these means to couple an NLS to the nucleic acid include synthesis of triplex oUgo- peptide, PNA-peptide, PCR fragment, plasmid DNA, restriction enzyme fragments, caping agents such as quadruplex, and spacers such as PEG and polyoxazoUne. PNA-NLS peptide bound to DNA: A linear DNA fragment containing the coding region from pCϊluc was prepared and amplified by PCR. The primers for the reaction were so designed that the linear fragment contained the sequences AAAGAGGG and GAGAGGAA on its 5' and 3' ends respectively. Peptide nucleic acid (PNA) sequences, X-O-O- TTTCTCCC-O-O-O-CCCTCTTT and Y-O-O-TTCCTCTC-O-O-O-CTCTCCTT were synthesized by soUd phase synthesis at Research Genetics (HunstviUe, AL). Here C and T are the cytosine and thymine PNA analogues and O is the 8-amino- 3.6-dioxaoctanoic acid linker. X stands for the SV40 large T-antigen NLS sequence PKKKRKVEDPY, whUe Y is rhodamine. The two compounds were purified by HPLC and analyzed by mass spectroscopy. The two PNA molecules were designed to form a "clamp" with the complementary 5' and the 3' ends of the linear DNA fragment as Ulustrated in Figure 10A. The DNA-PNA complex was formed by mixing a 20 times molar excess of two PNA molecules with the linear DNA and incubating for lh at 37 OC. The complex was then separated from the unbound material in a Centricon separator (MWCO= 10,000 D,) and visualized by electrophoresis on a 1% agarose gel foUowed by UV irradiation to luminate the rhodamine label. The gel was then incubated in ethidium bromide foUowed by UV lu ination. The rhodamine and the DNA bands were seen to overlap iUustrating their intimate association. The material was subsequently complexed with PEI as described eariier and used to transfect SMI and HUVEC ceUs in culture at various doses. The ceUs were lysed and luciferase expression evaluated after 24h by methods described earUer. The results of the transfection demonstrate clearly that the Unear DNA fragment containing the PNA-NLS is far more efficient in transfecting both the ceU-types tested (Figure 10B). At the highest dose, there is not a significant difference between the expression levels attained by the PNA-NLS conjugated DNA and the control fragment, but as the dose is reduced down from 200 to 50 ng, the NLS containing DNA transfects the ceUs more efficiently. This construct maintains its high transfection efficiency over the whole range in both the ceU-types tested, whUe the control fragment is down to barely above-background levels. One explanation would be that at the highest dose, the nuclear import machinery is saturated and hence there is not a significant difference between the two constructs. As the dose is decreased, the DNA containing the NLS fragment is far more actively transported into the nucleus and hence is able to maintain its high levels of transfection. It is important to note however that this construct lacking the PNA-NLS contains a free unprotected end and may be susceptible to exonuclease degradation. For this construct, DNA degradation within the ceU cannot be ruled out as a reason for the lower transfection levels observed, especiaUy at the lower doses, when a significant fraction of the DNA may be unavaUable. Synthesis of Linear DNA - NLS peptide conjugate: Strategy: Synthesize a Unear DNA fragment by PCR amplification from a plasmid DNA such that the Unear DNA obtained has a conjugation site at one end and a sequence that folds into a structure that provide protection from exonucleases. 5' XCAT GGC TCG ACA GAT CTT CAA TA 3' (FB 1) (X: C6 linker with amine) 5' XιX 2 X 2 TGG GTT TTG GGT TTT GGG TTT TGG GTT TGG ATC CGC TGT GGA ATG TG 3' (PB) (XI : acridine, X 2 , X 3 : C9 linker) PCR protocol: PCR amplification was carried out using standard protocol. Reaction mixture had the foUowing reagents: 1. PCR Master Mix 50μl 2. Sterile distiUed water 32μl 3. Primer 1 (100ng/μl)8μl 4. Primer 2 (100ng/μl)8μl 5. Template (lng/μl, 10 6 copies) 2μl PCR Master mix contains PCR buffer IX, 2.5U TaqPolym in Brij 35, 0.005%(v/v) dATP, dCTP, dGTP, dTTP each 0.2 mM, 10 mM Tris-HCl, 50 mM KC1, 1.5 mM MgCl 2 PCR conditions: 1 94°C 1 min 2. 94°C (denaturing) 1 min 3. 60°C (Annealing) 1 min 4. 72°C (Extension) 1 min Steps 2-4 repeated 38 times 5. 72°C 2 hrs Conjugation of NLS peptide to DNA through PEG2000: The NLS peptide with amino acid sequence, PKK KRK VED PYC was obtained from Genemed Synthesis Inc. and was synthesized using soUd phase method using Fmoc chemistry. The peptide was purified to > 90% purity using reverse phase HPLC. Prior to reaction with DNA, the peptide was treated with 20 mM DTT. DTT treated peptide was purified on a G25 gel filtration column in order to remove free DTT using 0.1% acetic acid as solvent. Peptide was stored in 0.1% acetic acid until its reaction with PEG conjugated DNA. Linear PCR DNA obtained from the PCR ampUfication was purified by extensive dialysis against 10 mM HEPES containing 50 mM NaCI using a 50,000 MWCO dialysis tubing at 4 °C. 300 μg of PCR DNA was dissolved in 2 ml lOmM HEPES at pH 7.5, containing 1.5M NaCI. 1.5 mg of N-Hydroxy succinimide PEG vinyl sulfone (NHS-PEG2000-VS), obtained from Shearwater Polymers, dissolved in 0.1 ml DMSO (dimethyl sulfoxide) was added to DNA and stirred at 4 °C for 16 hours. The reaction mixture was transferred into a 50,000 MWCO dialysis tube and dialysed against lOmM HPES containing 1M NaCI, with frequent change of buffer, at 4°C in order to remove the unreacted PEG derivative. Salt concentration in the DNA solution was raised to 2M. lmg of the NLS peptide dissolved in 10 mM HEPES was added to the DNA solution and the pH of the solution was adjusted to 8.0 using dUute NaOH. The reaction mixture was kept at 4 °C with sterring for 16 hours. Reaction mixture was then dialyzed extensively against lOmM HEPES containing 2M foUowed by 1M NaCI. Sample was stored in 10 mM HEPES containing 1M NaCI. Example 50: Synthesis of PEI-PEG conjugates and effect of PEGylation on the size and stability of PEI/DNA complexes Materials and Methods PEI (25kD) was obtained from Aldrich Chemical Company (MUwaukee, W ) and Methoxy poly (ethylene glycol)-nitrophenyl carbonate (MW 5000) was obtained from Shearwater Polymers (Biπningham AL). Concentration of PEI solutions was determined using TNBS assay for primary amine content described below. DNA concentration was determined spectrophotometricaUy using a molar extinction coefficient of 13,200 mol "1 cm "1 per base pair at 260 nm (1OD = 50 μg DNA). Particle size of the coUoidal formulations were determined by Ught scattering measurements at 90° angle on a Coulter N4 particle sizer. Autocorrelation functions were analyzed either by unimodal analysis assuming a single population of particles or using SDP analysis assuming multiple populations using the software provided by the manufacturer. TNBS Assay: Reagents: TNBS: lOmM in water, Glycine HCl or any other primary amine standard: lOmM in H2O, Sodium carbonate or sodium bicarbonate buffer, pH 9.0, * TNBS can be purchased as solution in Methanol (5% w/v), Procedure: Prepare a set of standard solutions in the concentration range 5 μM to 0.1 mM in primary amines (glycine HCl can be used for this purpose) as foUows. Make 300μl of 0. ImM Glycine HCl in 100 mM buffer. Make several samples by a serial dUution of this sample, (eg. add 200μl of the above sample to 100 μl buffer to make a sample at 66.66μM concentration, transfer 200μl of the above sample to lOOμl of buffer to obtain 44.44μM sample and so on. Remove 200μl from the last sample after it is made so that aU the samples are at equal volume ie. lOOμl). Prepare lOOμl of the primary amine sample of unknown concentration in the same buffer in dupUcate or tripUcate. The concentration of this sample should be within the range of the standard curve. Add lOμl of TNBS into each sample and vortex. Incubate at room temperature for 30 minutes and read the absorbance at 420 nm. Subtract the absorbance of the blank (ie. lOμl TNBS dUuted into lOOμl of buffer) from that of each sample. Make a standard curve with the concentration of glycine against absorbance at 420 nm. From the slope and intercept of this plot and the absorbance of the sample, the concentration of primary amines can be calculated. Conjugation of PEI with PEG5000: 10 mg of PEI was dissolved in 100 mM NaHC0 3 at pH 9 and 6 lmg of methoxy-PEG5000-nitrophenyl carbonate (sufficient to modify 5% of PEI residues) was added and reacted for 16 hours at 4°C. The reaction mixture was then dialyzed extensively against 250 mM NaCI foUowed by water using a dialysis bag with a 10,000 MW cut-off. Synthesis of PEI conjugate of PEG350 was carried out using a simUar procedure as described for PEG5000 using nitrophenyl carbonates of PEG350, obtained fromFluka, MUwaukee, WI. The extent of PEG conjugation was estimated using the weight of the complex and the concentration of primary amine. Formation of anchored DNA /PEI-PEG complex: Complexes of DNA/PEI-PEG containing various molar concentration of PEG were prepared by hand mixing of equal volumes of DNA and PEI/PEI-PEG mixtures, foUowed by vortexing for 30 to 60 seconds. Cell Binding: Confocal microscopy The effect of PEG on the ceUular uptake of PEI DNA complexes was evaluated by fluorescence microscopy. A 3'- Rhodamine labeled phosphorothioate oUgonucleotide (5'-AAG GAA GGA AGG-3' -Rhodamine) obtained from OUgos Etc., WUsonvUle, Oregon, was used as the fluorescent marker. The labeled oUgonucleotide was complexed with PEI or PEI-PEG at 4:1 (+/-) charge ratio and incubated with HUNEC ceUs grown on microscope cover sUps in a six weU plate, for three hours in serum free medium. After the three-hour incubation, ceUs were washed with serum free medium and were aUowed to grow in the presence of growth medium for another 20 hours. These ceUs were then washed with PBS, fixed with 4% paraformaldehyde for 15 minutes and mounted on a hanging drop microscope sUde that contain PBS in the weU, with the ceUs facing the wett and in contact with PBS. The shdes were observed under a Laser Scanning Confocal 10 mg of PEI was dissolved in 100 mM ΝaHC0 3 at pH 9 and 6 lmg of methoxy- PEG5000-nitrophenyl carbonate (sufficient to modify 5% of PEI residues) was added and reacted for 16 hours at 4°C. The reaction mixture was then dialyzed extensively against 250 mM NaCI foUowed by water using a 10,000 MW cut-off dialysis bag. Synthesis of PEI conjugates of PEG2000, PEG750 and PEG350 were carried out using simUar procedure described for PEG5000 using nitrophenyl carbonates of the respective PEGs, obtained fromFluka. Amount of PEG conjugation was estimated comparing the weight of the complex and the concentration of primary amine. Formation of DNA /PEI-PEG complex: Microscope (MRC 1000, Bio-Rad) using a 60X oU immersion objective. An Ar/Kr laser Ught source in combination with the optical filter settings for Rhodamine excitation and emission were used for acquisition of the fluorescence images. Biological Activity: Transfection Transfection efficiency of PEI and PEI-PEG complexes was studied using a plasmid DNA pCI-Luc containing Luciferase reporter gene, regulated by CMV promoter. CeUs (BL6) were plated at 20000 ceUs/weU in 96 weU plates and aUowed to grow to 80 - 90% confluency. They were then incubated with PEI or PEI-PEG / DNA complexes prepared at a charge ratio of 5 (+/-) and a DNA dose of 0.5 μg DNA per weU, for 3 hours in serum free medium at 37°C. CeUs were aUowed to grow in the growth medium for another 20 hours before assaying for the luciferase activity. Luciferase activity in terms of relative Ught units was assayed using the commerciaUy avaUable kit (Promega) and read on a luminometer, using a 96 weU format. Results Colloidal Stability Figure 11 shows the effect of PEG conjugation (PEGylation) on the particle size distribution of PEI DNA complexes prepared at various charge ratios. Without PEGylation, PEI/DNA complexes have a size distribution that depends upon the charge ratio. At a net negative charge, the particles formed were quite smaU (about 100 nm). At near neutral charge ratios, however, PEI/DNA complexes formed or aggregated into large particles. As the charge ratio was increased to net positive, the particle size decreased, probably due to surface charge repulsion that reduces association. With PEGylated PEI, DNA complexes are smaU, and the size independent of charge ratio, even at relatively high concentration of DNA, and even without using special mixing techniques. For these experiments, DNA was complexed with PEGylated PEI, where about 5% of the PEI amine residues were conjugated with PEG5000. This appears to result in PEG on the surface of these particles, effectively reducing association phenomena, even for charge neutral complexes. Without being bound by any theory, it is beUeved that these effects are attributable to the PEG providing a steric barrier on the surface of the complex. It is known that PEI/DNA complexes tend to aggregate into larger particles over hours and days. This instability is an undesirable property of conventional complexes. Figure 12 demonstrates that coUoidal stabiUty over a period of several days can be attained by PEGylation of PEI with a PEG-PEI DNA complex prepared at 1 : 1 charge ratio. Mean particle size remained smaU even for a period of several days. These data show that PEGylation provides the long-term stabiUty necessary for successful use of these coUoidal formulations in gene therapy appUcations. In sum, a smaU amount of PEG (5 mol%) derivatization of PEI facilitates formation of smaU particles and provides substantial stabiUty to the complex. Effect of Serum It is widely known that most positively charged DNA complexes lose their abiUty to transfect ceUs in the presence of serum. This inactivation may involve interactions with negatively charged semm leading to aggregation of these particles and / or destabilization of the complex. Anchoring of PEG to the DNA complex can be used to address this problem. Figure 13 shows the effect of semm on the particle size distribution of PEI DNA and PEI-PEG/DNA complexes. On incubation with serum, conventional positively charged PEI DNA complexes aggregate substantiaUy, as evidenced by the increase in the average particle size distribution from about 100 nm to more than 500 nm(0 mol% PEG). This may be due to the binding of serum proteins on the surface of these complexes mediating aggregation. With the anchored complexes containing PEG5000 PEGylated PEI, protection from aggregation occured at levels greater than 1 mol%. The effect appeared to saturate by 3 mol%. This effect depends on the molecular weight of the polymer. PEG350 was ineffective to prevent the serum-mediated aggregation even up to the maximum mol% tested, as shown in the Figure 13b. Without being bound by any theory, it is possible that the length of this polymer may be too short to provide any significant steric barrier to protein binding or the polymer may not have formed a surface coat. The structure of the anchored complex might be visualized as an extended polymer chain reaching above an adsorbed protein sheU on the surface of the particle providing a steric barrier to particle - particle association (Figure 14A). Thus, protein adsorption may be reduced, go unchanged, or even be increased, and the extra protein may help form a barrier to aggregation or the specific proteins increased on the surface may be beneficial. These data demonstrate that a hydrophiUc polymer, such as PEG, affects coUoidal and biological property of cationic particles formed by PEI and DNA. A steric PEG coating apparently was formed on the surface of PEI/DNA complexes when the PEG was anchored to the DNA complex via a covalent bond to the PEI. This coating led to reduced particle size distribution, enhanced coUoidal stabUity, and enhanced seram stabUity, aU of which are desirable properties of gene deUvery systems. Biological Activity Biological activity of PEI/DNA complexes is known to be be dependent on the charge ratio (+/-) of the complex. At net cationic charge ratios, PEI/DNA complexes, in the absence of any receptor mediated interaction, may bind to the ceU surface simply through electrostatic interaction. At lower charge ratios (+/- <1), where the complex is net negatively charged and the electrostatic binding with ceU surface is expected to be minimal, these complexes transfect ceUs very inefficiently. At high charge ratios (+/- >1), where the complex is net positively charged, electrostatic interaction with the negatively charged ceU surface may be sufficient for bmding and subsequent ceUular uptake by endocytosis or simUar mechanisms. A PEG coating on the surface of the particles may modulate the interactions of complexes. The effect of surface PEG is to reduce electrostatic interactions and create a steric barrier. For in vitro transfections, the resulting decreased binding to the ceU reduces or eliminates the uptake and inhibits expression. For in vivo systemic apphcation, decreased protein and ceU interaction should increase the blood circulation time and minimize nonspecific interactions thereby increasing the probability of the complex reaching a target tissue. Figure 20 shows the effect of PEGylation on the in vitro transfection efficiency of PEI/DNA complexes at a charge ratio of 5 over a range of 0 to 5 mole percent of PEGylated PEI and with different molecular weight PEG. Activity is measured as plasmid expression of the reporter gene luciferase. PEI DNA complexes at this charge ratio transfect the ceUs reasonably weU as shown by high luciferase expression. Presence of PEG in the complex inhibits expression in a manner highly dependent on the molecular weight and mol% of PEG. This inhibition is attributed to inhibition of binding and or subsequent intraceUular processing of the complex. A PEG molecular weight equal or greater than 2000 shows decrease in expression as the mol% of PEG in the complex is increased. The effect of 2000 molecular weight PEG seems to saturate at 3 mol% whole the effect by 5000 molecular weight PEG saturates at 4 mol%. PEG350 or PEG750 up to 5% seems to have no significant effect on the activity of the complex. Presence of a PEG coating, as described above, can influence biological activity of the complex through several ways. The polymer coat on a positively charged particle may act essentiaUy to mask the surface charge thereby reducing binding mediated by electrostatic interaction. It can also act as a steric barrier on the surface that interferes with the binding process. A possibility also exists that steric polymers have an effect on the endosomal escape mechanism. SmaU molecular weight (short chain length) polymers appear to have no effect upto 5 mol%. It is likely that these smaU polymers provide insufficient masking. It is not known, however, whether the screening or the steric barrier, or both, is inadequate. Accordingly, it is important to understand the mechanism by which PEG modulates the activity of the complex. Example 51: Preparation of a sheddable PEG coat on a PEI/DNA complex In addition to its stabilizing effect on DNA complexes, the presence of an anchored protective layer may impact subsequent steps in the DNA deUvery process. In particular, presence of a steric layer may be detrimental to escape of the complex from the endosome, a process that may require close interaction between the complex and endosomal membrane. One way to overcome any potential problem is to provide methods to cleave the anchored steric coat from the complex using chemical or enzymatic procedures. This example demonstrates that a sheddable coat on a particle surface can be generated using a cleavable disulfide bond for conjugation of PEG to PEI. Example 44 showed that a steric PEG coating can be formed on the surface of PEI DNA complexes that provides improved coUoidal stabiUty for the formulation. This example shows that the steric coat can be cleaved off, for example, under reducing conditions. Materials and Methods PEI (25kD) was obtained from Aldrich Chemical Company and Methoxy poly (ethylene glycol)-nitrophenyl carbonate (MW 5000) and mercaptopolyethylene glycol 5000 monomethyl ether were obtained from Shearwater Polymers and Fluka respectively. Surface charge on the coUoidal particles was determined from the electrophoretic mobUity of these particles measured using a Delsa 440SX from Coulter Corporation. Other experimental conditions were as described in Example 1. Conjugation of PEI with PEG5000: 10 mg of PEI was dissolved in 100 mM NaHC0 3 at pH 9 and 61mg of methoxy-PEG5000-nitrophenyl carbonate was added and reacted for 16 hours at 4°C. The reaction mixture was then dialyzed extensively against 250 mM NaCI foUowed by water using 10,000 MWCO dialysis bag. Amount of PEG was estimated from the primary amine concentration and weight of dried sample. PEI linked by a disulfide bond to PEG (PEI-ss-PEG) was synthesized by the foUowing procedure. 20 mg of PEI was dissolved in 250μl of DMSO. 8mg of SPDP was added to this solution and aUowed to react for 16 hours at 4°C, during which the reaction mixture became gel-Uke. 100 mg of mercaptopolyethylene glycol 5000 monomethyl ether dissolved in 2ml of 10 mM Tris/pH8.0 was added to the above solution and reacted for two days, during which time the gel dissolved. The sample was dialyzed extensively for 3 days against water using a 10,000 MW cut off dialysis cartridge, with frequent change of water. Percentage of conjugation was estimated using two different methods in which either: (i) the amount of PEG was estimated from the primary amine concentration and weight of dried sample; or (U) the conjugate was treated with DTT. After removing DTT by dialysis using a 10,000 MW cut-off dialysis membrane, the ratio of primary amine to sulfhydryl ratio was determined using TNBS (RDS#) and EUman's assay. The two procedures gave a very simUar value. Formation of DNA /PEI-PEG complex: Complexes of DNA/PEI-PEG containing various molar concentration of PEG were prepared by hand mixing of equal volumes of DNA and PEI/PEI-PEG mixtures foUowed by vortexing for 30 to 60 seconds. Cell Binding: Confocal microscopy Effect of PEG on the ceUular uptake of PEI DNA complexes was evaluated by fluorescence microscopy. A 3'- Rhodamine labeled phosphorothioate oUgonucleotide (5'-AAG GAA GGA AGG-3' -Rhodamine) obtained from OUgos Etc., WUsonvUle, Oregon, was used as the fluorescent marker. The labeled oUgonucleotide was complexed with PEI or PEI-PEG at 4:1 (+/-) charge ratio and incubated with HUVEC ceUs grown on microscope cover sUps in a six weU plate, for three hours in serum free medium. After the three-hour incubation, ceUs were washed with serum free medium and were aUowed to grow in the presence of growth medium for another 20 hours. These ceUs then were washed with PBS, fixed with 4% paraformaldehyde for 15 minutes and mounted on a hanging-drop microscope sUde containing PBS in the weU, with the ceUs facing the weU and in contact with PBS. The sUdes were observed under a Laser Scanning Confocal Microscope (MRC 1024, Bio-Rad) using a 60X oU immersion objective. An Ar/Kr laser Ught source in combination with the optical filter settings for Rhodamine excitation and emission was used for acquisition of the fluorescence images. Biological Activity: Transfection Transfection efficiency of PEI and PEI-PEG complexes was studied using a plasmid DNA pCI-Luc containing a Luciferase reporter gene, regulated by a CMV promoter. CeUs (BL6) were plated at 20,000 ceUs/weU in 96 weU plates and aUowed to grow to 80 - 90% confluency. They then were incubated with PEI or PEI-PEG / DNA complexes prepared at a charge ratio of 5 (+/-) and a DNA dose of 0.5 μg DNA per weU, for 3 hours in serum free medium at 37°C. These ceUs were aUowed to grow in the growth medium for another 20 hours. The ceUs were lysed and luciferase activity was assayed (measured in relative Ught units) using a commerciaUy avaUable kit (Promega, Madison, WI) with a luminometer using 96 weU format. Results Example 44 shows that anchoring of PEG to PEI provides long term coUoidal stabiUty to a PEI/DNA complex and helps to make small particles. It also shows that the presence of a steric protective layer, such as PEG, in the complex reduces the non-specific interaction with seram proteins as weU as ceU surface. The results described below show the effect on the physico-chemical and biological properties of PEI/DNA complex of using a cleavable steric layer. Figure 16 shows the particle size of a PEI/DNA complex, where the PEI contained 11% of its residues conjugated with PEG through a disulfide bond. These complexes were made at a charge ratio (+/-) of 1, where the size of conventional particles would be very large (Example 44 and Figure 11). Contrary to a very large size, the complex was found to be relatively small, with an average size of 150 nm. When PEI-ss- PEG was pre-treated with 10 mM DTT before mixing with the DNA, particles formed were very large and precipitated out of solution within a few minutes. These data demonstrate the stabilizing effect of the anchored steric surface (PEG) and that cleavage of the PEG disulfide Unker by reduction removes the surface PEG and its stabilizing effects. For the anchored steric barrier to affect particle aggregation and reduce non-specific interaction, it must be presented at the surface of the particle. When PEGylated PEI is mixed with DNA to form particles, some of the PEG molecules could be trapped within the hydrophobic core of the complex and may not be accessible to chemical or enzymatic cleavage. However, since PEG is a hydrophiUc polymer, a large fraction of it can be expected to be at the surface. Cleavage of this surface polymer may affect the particle properties significantly. One of the consequences of having the steric polymer at the surface of positively charged particles is that it masks the surface charge. Measurement of Zeta potential can be used to probe the presence of a polymer layer at the surface. Such a layer would reduce the effective surface charge, and the extent of the reduction would depend on the length of the polymer. Figure 17 shows the Zeta potential of PEI and PEI-ss-PEG5000 complexed with salmon sperm DNA at a charge ratio of 3 (+/-). A PEI/DNA at this charge ratio has a positive zeta potential of about 24 mV. DNA complexed with PEI-ss- PEG at the same charge ratio showed a much lower Zeta potential (12 mV)demonstrating the shielding of the surface charge by PEG. This complex contained 5 mol% (with respect to total amines on PEI) PEG. This zeta potential was very simUar to that obtained for the PEI DNA complex containing 5 mol% PEG, where PEG was linked to PEI through a stable linkage. Treatment of this complex with 10 mM DTT resulted in an increase in the Zeta potential (21 mV), indicating the removal of the anchored steric PEG layer from the surface. Treatment of PEI-ss-PEG with DTT before complexation with DNA gave a value simUar to that of the PEI DNA complex (22 mV). These results clearly demonstrate the presence of PEG on the surface of the complex and also its cleavabflity, when linked by disulfide, under reducing conditions. Colloidal Stability The results shown below demonstrate that presence of the cleavable anchor did not adversely affect the coUoidal stabUity of the PEGylated complexes. Figure 18 shows the long term stabiUty of PEI-ss-PEG DNA prepared at a charge ratio of 1. Average particle size distribution of this formulation remained constant over a long period of time. This is consistent with results obtained for the PEI-PEG/DNA in Example 44. To see the effect of removing the disulfide linked PEG from the surface of the complex, 10 mM DTT was added to the sample. Average particle size increased from 88 nm to 104 nm and remained more or less unchanged with time. Biological Activity For PEI DNA, in the absence of any Ugands attached to the complex, initial ceU binding step in DNA trafficking process is mediated by electrostatic interactions. The presence of a steric barrier (PEG) on the surface of the complex affects its physical properties in at least two distinct ways: 1) the polymer coat may physicaUy block the interaction with ceU surface and 2) it can mask surface charge so that binding mediated through electrostatic interactions is reduced. Thus a steric coat may be utilized to inhibit non-specific interactions. Use of a steric surface, for example by PEGylation of a PEI/DNA complex, can be used to inhibit unwanted biological activity. This is important since it provides a way to control non-specific interactions that lead to toxicity. Confocal imaging using fluorescent labeling demonstrates that the likely reason for such inhibition of activity is diminished binding to ceUs. Binding activity may be restored by linking ceU or tissue specific Ugands at the distal end of the steric polymer and/or by cleaving the steric polymer off the complex surface by a chemical or enzymatic trigger. This latter method can be accompUshed by conjugating PEG to PEI through a cleavable disulfide linkage. Figure 19 shows the biological activity of PEI-ss-PEG DNA and PEI- PEG DNA at various mol% PEG in the complex. PEI/DNA at positive charge ratios transfected BL-6 cells efficiently. CeUs transfected with PEI-PEG/DNA complex reduced the activity significantly on increasing the amount of PEG in the complex. Activity was essentiaUy eliminated for complexes that contain >3 mol% PEG. In this case PEG was conjugated to PEI through a stable linkage. However, ceUs transfected with PEI-ss-PEG/DNA showed high activity even up to 5 mol% PEG. These particles retained their activity in spite of steric coating provided by conjugated PEG. Presence of PEG on the surface of the complex linked either through stable or labUe linkage is expected to be inhibitory to ceU binding and uptake. However, the high biological activity of PEI-ss-PEG/DNA complexes indicates that the PEG linked through disulfide bond in PEI-ss-PEG/DNA is cleaved off during the incubation or at a later stage in the DNA trafficking process. Confocal images of HUVEC ceUs incubated with fluorescent labeled oUgonucleotide complexed with PEI or PEI-ss-PEG showed that the PEI/oUgonucleotide complex was internalized very efficiently, as indicated by the large amount of fluorescence within the ceU. In contrast, ceUs incubated with PEI- ss-PEG/oUgonucleotide complex showed considerably low internal fluorescence. Binding and uptake was greatly reduced as observed in the case of PEI- PEG/oUgonucleotide complex. Example 52: Synthesis of PEI-PMOZ conjugates and effect of conjugation on surface properties and transfection activity Materials and Methods 4-Nitrophenol, bis(4-nitrophenyl) carbonate, triethylamine, dicyclohexyl carbodiimide, anhydrous acetonitrUe and ahydrous dichloromethane were purchased from Aldrich (St. Louis, MO). Synthesis of PMOZ and PEOZ Poly(2-methyl-2-oxazoUne) with end-group propionic acid (PMOZ- propionic acid) and poly (2-ethyl-2-oxazoline) with methyl end-group (PEOZ) were prepared as described by S. ZaUpksy et al (J. Pharm. Sci. 85:133 (1996)). Gel permeation chromatography (GPC) was measured using the Hewlett Packard 1100 HPLC equipped with G-3000 PW and G-2500 PW columns (Schimadzu) placed in series and caUbrated by PEG standards in water. H-NMR spectra were measured in D 2 0 at 360 MHz (Spectral Data Services Inc, Champaign, IL). Activation of PMOZ - Preparation of 4-nitrophenyl ester of PMOZ- propionic acid PMOZ-propionic acid (MW: 9100, 0.129 mmol of propionate end group) was azeotropicaUy dried in 10 ml anhydrous acetonitrUe twice. The polymer was then dissolved in 3 ml anhydrous dichloromethane and 4-nitrophenol (2.87 mmol) was added. The mixture was cooled to 0°C and 2.62 mmol dicyclohexylcarbodiimide (DCCI) in 2 ml anhydrous dichloromethane was added. After 30 min, the mixture was aUowed to warm to room temperature and aUowed to incubate for 16h. The reaction mixture was then added dropwise to 300 ml anhydrous diethyl ether while being stirred. The supernatant was discarded, the precipitate dissolved in anhydrous acetonitrUe and the precipitation in diethyl ether repeated 3 times to give 4-nitrophenyl ester of PMOZ-propionic acid (0.545g) as a white powder. Activation of PEOZ - Preparation of 4-nitrophenyl carbonate of PEOZ PEOZ (M.W. 8850, 0.1 mmol of hydroxyl end group) and triethylamine (0.25 mmol) were dissolved in 10 ml anhydrous acetonitrUe. A solution of bis(4- nitrophenyl) carbonate (2.5 mmol) in 10 ml anhydrous acetonitrUe was added with stirring whUe maintaining the temperature at 0°C. The mixture then was aUowed to warm to room temperature and reaction continued for 20h. The reaction mixture was then concentrated, re-dissolved in 5 ml anhydrous acetonitrile and added dropwise to an anhydrous mixture of 500 ml diethyl ether and 10 ml dichloromethane with stirring. The supernatant was removed and precipitate dissolved in 5 ml acetonitrUe and re-precipitated in the ethyl acetate - dichloromethane again. The coUected precipitate of the 4-nitrophenyl carbonate of PEOZ (0.59 g) was a white soUd. A TLC test on sUica gel plates (eluant: ethyl acetate) indicated the absence of bis(4-nitrophenyl)carbonate. Conjugation of PMOZ with PEI 43 mg of PEI was dissolved in 0.1M bicarbonate buffer at pH 9.0. 545 mg of the activated PMOZ was added and aUowed to react at room temperature overnight. FoUowing reaction, the pH was lowered to 5 by the addition of concentrated HCl. The Uberated nitrophenol was extracted by chloroform treatment 5 times. Briefly, the reaction mixture was mixed with 100 ml chloroform in a separating funnel, shaken vigorously and aUowed to stand and separate into two phases. The nitrophenol was carried preferentiaUy into the chloroform phase which was removed, foUowed by addition of fresh chloroform and the process was repeated. The material was then dried and re-dissolved in 10 ml deonized water foUowed by dialysis against 150 mM NaCI with 2 changes of buffer, foUowed by dialysis against deionized water with 4 changes over 2 days. The product was then lyophilized and the PMOZ loading and amine content determined by NMR. Conjugation of PEOZ with PEI 32.035 mg of PEI was dissolved in 5 ml 0.1M borate buffer at pH 8.0. 590 mg of the activated PEOZ was dissolved in 4 ml acetomtrUe and added to the PEI solution whUe stirring. After 5 min a precipitate was observed which disappeared upon addition of 15 ml borate buffer. The reaction mixture was aUowed to react at room temperature overnight. FoUowing reaction, the material was dried in a rotovaporator to remove aU the acetonitrUe. The pH was then lowered to 5 by the addition of concentrated acetic acid. The hberated nitrophenol was extracted by chloroform as described above. This was foUowed by further extraction with ethyl acetate to remove most of the remaining nitrophenol. The material was then dried, re-dissolved in 10 ml deionized water, and dialyzed agamst 0.1M acetic acid with 2 changes and then against deionized water with 4 changes over 2 days. The product was then lyophilized and the PEOZ loading and amine content determined by NMR. Formulation of anchored DNA/PEI-PMOZ complexes Complexes were formed as described previously. Biological Activity: Transfection Biological activity was measured in BL-6 ceUs as described in Example 45. Results Surface properties and Colloidal stability Figure 22 shows the effect of the PMOZ on the surface properties of the complex. The complexes were formulated at a charge-ratio of 4:1 and the zeta- potential measured in 10 mM saline. With no PMOZ present, the particles demonstrate a highly positively charge surface as demonstrated by a zeta potential of +30 mV. With just a 1.6 % loading of PMOZ in the complex, the zeta potential reduces to 6.46 mV. Increasing the loading to 3.2 % results in a further reduction to 5.35 mV. These data suggest that, during the self-assembly process, the hydrophiUc PMOZ molecules prefer to be present on the surface of the complex rather than the hydrophobic interior and thereby act a steric barrier to reduce the apparent charge presented by the surface. This hydrophiUc and uncharged surface can be envisaged to reduce interactions with large serum components such as proteins. Such a phenomenon was indeed observed, as shown in Figure 23, where 4: 1 charge ratio complexes were prepared with varying amounts of PMOZ from 0 to 3.2 % (in steps of 0.8) were investigated for particle-size, before and after a 2h incubation in PBS containing 10% FBS at 37 °C. The stabiUty of the complexes in serum (as measured by the ab ity to maintain their size) was in direct proportion to the amount of PMOZ present in the complex. This indicates that the complexes are stable in serum, which is a critical component of targeting to specific tissues. Blocking non-specific transfection Figure 24 shows the result obtained using the complexes described above to transfect BL-6 ceUs in culture. There is a clear relationship between the amount of PMOZ present in the complex and its abiUty to transfect ceUs. Increasing amounts of surface PMOZ reduced the expression levels of luciferase in these ceUs. As discussed above, the presence of PMOZ hinders non-specific interaction of the complexes with the ceU-surface by acting as a steric and electrostatic barrier. This reduced interaction lowers uptake of the nucleic acid into the ceU resulting in lower transfection levels. This aUows one to design a complex that is selective to any target by the attachment of a Ugand to the distal end of the PMOZ. In this design an optimal number of Ugand molecules can be appended to a steric polymer far from the surface of the particle, aUowing for efficient interaction with a target receptor. Example 53 Preparation of ligand-targeted, layered colloid complexes with outer steric coating Preparation of PEI-PEG-RGD: Synthesis and purification: RGD peptide with sequence, ACR GDM FGC A, cycUzed through the Cys sidechains and purified to >90% by reverse phase HPLC (C18 column) was obtained from Genemed Synthesis, S. San Francisco. 16.8 mg of the RGD peptide was dissolved in lOO M HEPES buffer at pH 8.0. To this solution, 41 mg of VS- PEG3400-NHS (Shearwater Polymers) dissolved in dry DMSO (lOOμl) was added slowly (over 30 minutes) with stirring using a syringe pump. The reaction mixture was kept stirring at room temperature for another 7 hours. 5mg of PEI solution after adjusting the pH to 8.0 was added to the above reaction mixture. pH of the reaction mixture was raised to 9.5 and kept for stirring at room temperature for 4 days. At the end of the reaction, the reaction mixture was lyophilized. The sample was redissolved in 5 mM HEPES at pH 7.0 containing 150mM NaCI and passed through a G-50 gel filtration column using an elution buffer containing 5 mM HEPES and 150 mM NaCI. Void volume fraction was dialyzed extensively against 5 mM HEPES containing 150 mM NaCI using 25,000 MWCO dialysis tubing. The sample was desalted later by dialyzing against water using 3500 MWCO bag. Estimation of peptide conjugation: Amount of peptide in the conjugate was determined by estimating the sulfhydryl concentration from Cys side chains. A smaU fraction of the conjugate was treated with 20 mM DTT to reduce the peptide disulfide bond. This sample was then dialyzed against 0.1M acetic acid containing 1 mM EDTA using a 25000 MWCO dialysis tube, in order to remove excess DTT. After extensive dialysis, the sulfhydryl concentration was determined using EUmen's reagent and the amine concentration due to PEI was determined using TNBS assay for primary amines. Based on these assays, peptide conjugation to the PEI was estimated to be 10%. DNA binding: AbUity of PEI-PEG-RGD2C to complex with DNA was verified by gel elecfrophoresis experiments. Complexes formed at or above a charge ratio of 1 fafled to migrate into the gel, indicating complete charge neutralization of DNA due to binding of the conjugate. Particle Size and Zeta Potential: In order to faciUtate the uptake of DNA/polycation complexes, DNA needs to be condensed into smaU particles that can be endocytosed by ceUs. AbUity of PEI-PEG-RGD2C to condense DNA into smaU particles was studied by particle size measurements. Table 14 below shows the particle size of DNA/PEI-PEG- RGD2C at various charge ratios. Table 14 also shows the zeta potential values of DNA/PEI-PEG-RGD2C complexes at various charge ratios. Zeta potential remains low at these charge ratios indicating the formation of a steric coat that masks the surface charge of the complex. Table 14 Charge Particle Std. Zeta Std. ratio size(nM) deviation potential deviation 1.0:1 405.6 186.6 -13.3 3.65 1.2:1 579.1 267.5 -4.92 2.27 2.0:1 58.1 24.8 6.89 6.67 4.0:1 34.9 14.8 8.98 7.81 10.0:1 23.3 10.5 9.72 10.5 CeU binding and uptake: AbiUty of PEI-PEG-RGD2C to dehver nucleic acids to ceUs were studied using confocal microscopy using fluorescently labeled oUgonucleotide. Confocal microscopy experiments were carried out as described earUer (Example 51). Figure 28 Increased ceUular uptake of Rh-labeled oUgonucleotides complexed with PEI by addition of a peptide Ugand (RGD) to the distal end of PEG- Conjugated PEI in HELA ceUs at charge ratio 6. The figure shows the deUvery of fluorescently labeled oUgonucleotide by PEI or PEI-PEG-RGD2C to Hela and HUVC ceUs. In Hela ceUs bearing integrin receptors there is a marked increase in the amount of oUgonucleotide internalized when the deUvery is mediated by PEI- PEG-RGD2C as compared to PEI alone. Distribution pattern is also very different. With PEI, oUgonucleotide is distributed in the cytoplasm in vesicular compartments whereas with PEI-PEG-RGD2C, majority of the oUgonucleotide is located in the nucleus. Example 54 Preparation of ligand-targeted, layered colloid complexes with sheddable outer steric coating Synthesis of Unear PEI conjugated with a hindered disulfide to poIyethyloxazoUne (PEOZ) at one end and to a peptide Ugand, RGD, at the other end is Ulustrated in Figure 27. As seen in Figure 27A the preparation of PEI-SS- PEOZ-RGD involves the polymerization of 2-ethyl-2-oxazoline monomer with ethyl iodoacetate and the subsequent methanoUc KOH hydrolysis to give the methylenecarboxylated PEOZ intermediate I. Condensation of the carboxylated group with l-amino-2-methyl-2-propane[2-pyridyldithio], foUowed by the derivitization of the terminal hydroxyl group with glutaric anhydride and condensation of the resultant carboxylated end-group with the N-terminal amine of the RGD peptide gives the 2-pyridyl protected-SS-PEOZ-RGD intermediate IV. Reduction with 25 equivalents of dithiothreitol at pH 5 for 8h produces the thiol HS-PEOZ-RGD V which can react with the 2-pyridyldithiopropionate derivitized linear polyethylenimine to give PEI-SS-PEOZ-RGD. It is possible to modify this last step by reducing 2-pyridyldithiopropionate derivitized linear polyethylenimine with 25 equivalents of dithiothreitol at pH 5 for 8h and then reacting the resultant thiols on the linear polyethylenimine with the 2-pyridyl protected-SS-PEOZ-RGD intermediate IV to give the same final product PEI-SS-PEOZ-RGD. Preparation of Methylenecarboxylated PEOZ Intermediate (I, Figure 27 A): Polymerization reaction was conducted in a screw-cap tube that was dried under vacuo while heated prior to use. The tube was charged with 4 ml of 2-ethyl- 2-oxazoline that was freshly distilled over KOH and 4 ml of dry acetonitrUe. 0.85 g of freshly distiUed ethyl iodoacetate was dissolved in 8 ml of dry acetonitrUe and 0.80 ml of this solution was transferred to the tube containing the monomer. After this transfer the tube was purged with argon, sealed and left stirring in oU bath at 80o C for 45 h. After cooling to room temperature 2 ml of a methanoUc solution of KOH (0.5M) was dded to the polymerization mixture foUowed by stirring at 25o C for 4 h. 0.15 ml of glacial acetic acid was added and the mixture concentrated to a soUd, redissolved in 50 ml of water and placed in 3500 molecular weight cutoff Spectral/Por dialysis membranes (Spectrum, Los AngeIes,CA). Dialysis was against 100 mM NaCI (1 x 3.5L) and water (3 x 3.5L). The content of the dialysis bags were lyophilized and further dried under vacuo to give 3.84 g of a white soUd (98%). 1H NMR ( 360 MHz D20) d 0.87-0.94 (m, CH3CH2C=0), 2.13-2.27 (m, CH3CH2C=0),3.37-3.46 (m, CH2N) The sample gave a positive ion MALDI-TOF mass spectrum showing a weak, broad distribution of possible pseudo-molecular ions between approximately m/z 8,000 and 13,000 and centered at approximately m/z 10,331 (expected m/z 10,075). Preparation of l-Amido-2-methyl-2-propane[2-pyridyldithio]- Methylenecarboxylated-PEOZ Intermediate (II, Figure 27A): 2g of methylenecarboxylated PEOZ intermediate (I, Figure 27) was dissolved in 100 ml of water and the pH adjusted with aqueous HCl to 6. The solution was concentrated under vacuo to a soUd which was then dissolved in 6 ml of dry dichloromethane. 0.273 g of 1-hydroxybenzotriazole monohydrate, 0.208 g of dicyclohexylcarbodUmide and 0.253g of l-amino-2-methyl-2-propane[2- pyridyldithio] was added and left to stir for 48 h. The reaction mixture was filtered and the filtrate was added dropwise to 1 L of diethyl ether with stirring. After decanting, the precipitate was dissolved in 5 ml of dichloromethane and again added to 1 L of diethyl ether with stirring. After decanting, the precipitate was dissolved in 50 ml of water and placed in 3500 molecular weight cutoff Spectral Por dialysis membranes (Spectrum, Los Angeles,CA). Dialysis was against 100 mM NaCI (1 x 3.5L) and water (2 x 3.5L). The content of the dialysis bags were lyophilized and further dried under vacuo to give 1.77g of a white soUd (86%). The resulting soUd was purified using C18 reverse phase hplc (Jupiter 300A, lOu, 250mm x 10mm) with solvent A as aqueous 0.1% trifluoroacetic acid and solvent B as acetonitrUe. The flow rate was 5ml per minute using gradient of 30% to 45% solvent B over 45 minutes. The product, l-Amido-2-methyl-2- propane[2-ρyridyldithio]-Methylenecarboxylated-PEOZ intermediate (II, Figure 27 A), was coUected from the peak eluting at 20 minutes into the gradient to give 0.88 g of a white solid (43%). 1H NMR (400 MHz D 2 0) δ 0.87-0.94 (multiple triplets, J=7.2, CH 3 CH 2 C=0), 1.16 (bs, [CH 3 ] 2 C), 2.13-2.28 (multiple quartets, J=7.3, CH 3 CH 2 C=0), 3.37-3.46 (m, CH 2 N and CH 2 OΗ), 3.92 (bs, NCH 2 C=0), 7.67 (bdd, jV2+J 2 /2=6.8, 4-H pyridyl), 8.16 (bd, J=8.3, 2-H pyridyl), 8.27 ( bdd, J^J^δ.10, 3-H pyridyl), 8.51 (bd, J=5.9, 5-H pyridyl) Preparation of l-Amido-2-methyl-2-propane[2-pyridyldithio]- Methylenecarboxylated-PEOZ -O-Glutaric monoester monoacid Intermediate (III, Figure 27 A) 0.05 g of l-Amido-2-methyl-2-propane[2-pyridyldithio]- methylenecarboxylated-PEOZ intermediate (II, Figure 27 A) was dissolved inl ml of dry acetonitrUe and 2 ml of dry toluene. The solution was concentrated in vacuo to a soUd. A solution of 0.014 g of glutaric anhydride in 0.5 ml of dry acetonitrUe was added foUowed by 0.025 ml of dry pyridine. The stirred mixture was placed in an oU bath at 80° C for 24 h. After cooling the mixture was concentrated under vacuo to a soUd, redissolved in 3 ml of aqueous 0.2 M sodium acetate pΗ 6.5 and appUed to Sephadex™ G-25 fine (column diameter 1.6 cm and 65 cm height). Product was eluted from the gel column using water and was coUected in the first fraction to give 0.04 g of a white soUd (80%). J Η NMR (400 MHz CD 3 OD) δ 1.07-1.12 (multiple triplets, J=7.3, 1.31 (bs, [CH 3 ] 2 C), 1.85-1.89 (m, OC=OCΗ 2 CH 2 CΗ 2 C0 2 Η), 2.18- 2.25 (m, OC=OCH2CH 2 CH2C0 2 H ), 2.36-2.47 (multiple quartets, J=7.3, CH 3 CH 2 C=0), 3.5-3.57 (m, CH 2 N and CH 2 OΗ), 4.09 (bs, NCH 2 C=0), 4.23-4.26 (m, CH 2 OC=O), 7.21-7.23 (m, 4-H pyridyl), 7.76-7.81 (m, 2-H and 3-H pyridyl), 8.42 (m, 5-H pyridyl) Preparation of l-Amido-2-methyl-2-propane[2-pyridyldithio]- Methylenecarboxylated-PEOZ -O-Glutaric monoester peptidyl RGDIntermediate (IV, Figure 27A) 0.03 g of l-Amido-2-methyl-2-propane[2-pyridyldithio]- methylenecarboxylated-PEOZ -O-Glutaric monoester monoacid intermediate (HI, Figure 27 A) is dissolved in 0.25 ml of dry chloroform and treated with 0.002 g of N-hydroxysuccinimde and 0.003 g of dicyclohexylcarbodiimide. The solution is stirred for 48 h at 25° C and then filtered. The coUected filtrate is added dropwise to stirred 100 ml of dry diethyl ether. After decanting, the precipitate is dissolved in 0.5 ml of dry acetonitrUe and added to 0.008 g of the bis-cycUzed GACDCRGDCWCG carboxyl terminated amide peptide (Genmed Synthesis, South San Francisco). 0.003 g of 1-methyUmidazole is added and the reaction is aUowed to stir at 25° C for 48 h. 3 ml of aqueous 0.2 M sodium acetate pH 6.5 is added and is placed in 3500 molecular weight cutoff Spectral Por dialysis membranes (Spectrum, Los Angeles, CA). Dialysis is against 100 mM NaCI (2 x 3.5L) and water (3 x 3.5L). The content of the dialysis bags are lyophilized and further dried under vacuo to give l-Amido-2-methyl-2-propane[2-pyridyldithio] methylenecarboxylated-PEOZ -O-Glutaric monoester peptidyl RGD intermediate (IV, Figure 27 A). Preparation of l-Amido-2-methyl-2-propanethiol methylenecarboxylated- PEOZ -O-Glutaric monoester peptidyl RGD intermediate (V, Figure 27 A) 0.02 g of l-Amido-2-methyl-2-propane[2-pyridyldithio] methylenecarboxylated-PEOZ -O-Glutaric monoester peptidyl RGD intermediate (IV, Figure 27 A) is dissolved in 0.5 ml of aqueous 0.2 M sodium acetate pH 5 containing 5 mM EDTA. The solution is purged with nitrogen and 0.008 g of dithiothreitol is added. Left to stir for 8 h and is then appUed to Sephadex™ G-25 fine (column diameter 1.6 cm and 65 cm height). Product is eluted from the gel column using aqueous 0.10 M acetic acid and is coUected in the first fraction to give l-Amido-2-methyl-2-propanethiol methylenecarboxylated-PEOZ -O-glutaric monoester peptidyl RGD intermediate (V, Figure 27 A). Preparation of 2-pyridyldithiopropionate derivitized linear polyethylenimine (VI, Figure 27 A) A solution of 0.013 g of N-succinimidyl-3-(2-pyridyldithio)propionate (SPDP) from Pierce, Rockford IL, in 0.5 ml of dry methanol is added to a solution of 0.022 g of free base linear polyethylenimine of MW 22 kDa in 0.25 ml of dry methanol. The reaction is stirred in the dark for 16 h. 10 ml of aqueous 0.5 M sodium acetate pH 6.5 is added and the resultant mixture is placed in 3500 molecular weight cutoff Spectral/Por dialysis membranes (Spectrum, Los Angeles,CA). Dialysis is against 0.5 M NaCI (2 x 2 L) and water (3 x 2 L). The content of the dialysis bags are lyophilized and further dried under vacuo to give 2- pyridyldithiopropionate derivitized Unear polyethylenimine (VI, Figure 27 A). Preparation of l-Amido-2-methyl-2-propaneditWo(polyethylenimine) methylenecarboxylated-PEOZ -O-Glutaric monoester peptidyl RGD intermediate (VH, Figure 27 A) 0.01 g of 2-pyridyldithiopropionate derivitized linear polyethylenimine (VI, Figure27 A) is dissolved in 0.1 ml of 0.2 M sodium acetate buffer pH 5 containing 0.1 M sodium chloride and 25 mM EDTA. The solution is purged with nitrogen. A solution of 0.125 g of 1 -amido-2-methyl-2-propanethiol methylenecarboxylated- PEOZ -O-glutaric monoester peptidyl RGD intermediate (V, Figure 27 A) in 0.5 ml of 0.2 M sodium acetate buffer pH 5 containing 0.1 M sodium chloride and 25 mM EDTA is then added. The reaction mixture is stirred for 8h. The extent of the coupling can be determined by measuring the absorbance at 343 nm for the pyridine-2-thione that is released. Molar extinction coefficient at 343 nm = 8.08 x 10 3 M "3 cm "1 . The reaction is terminated by the addition of 0.01 g of mercaptoethanol. Further stirring is continued untU aU pyridine-2-thione has been released. 10 ml of aqueous 0.5 M sodium acetate pH 4 is added and the resultant mixture is placed in 25,000 molecular weight cutoff Spectral Por dialysis membranes (Spectrum, Los Angeles,CA). Dialysis is against 0.5 M NaCI (2 x 2 L) and water (3 x 2 L). The content of the dialysis bags are lyophilized and further dried under vacuo to give l-arddo-2-methyl-2-propanedit o(polyethylenimine) methylenecarboxylated-PEOZ -O-Glutaric monoester peptidyl RGD intermediate (VH, Figure 27 A). PEI-SS-PEOZ-RGD and PEI-SS-PEOZ were mixed in different ratios to obtain different molar concentrations of the Ugand containing molecule. These mixtures were then combined with plasmid DNA (pCHuc) as described above to produce complexes at a 4:1 +/- ratio. The complexes were dUuted into a 10 mM NaCI, 1 mM EDTA solution and zeta-potential determination in the DELSA 440 (Coulter Corp. Miami, FL) was used to estimate the thickness of the "surface coat". HUVEC ceUs were then transfected and luciferase activity assayed at 24h, 48h and 72h post-transfection to determine the optimal Ugand amount and differences in expression-kinetics (if any). The control for the experiment was positively-charged complexes lacking the targeting coat Ligand specificity was tested in competition-assays against free Ugand and in ceUs that were receptor- negative. These complexes were injected via the taU vein into CD-I mice, various organs and blood-vessels were isolated and examined for luciferase expression to see differences versus control formulations. Example 55. Gene deUvery to and expression by human synoviocytes. The cationic Upids described in the invention, specificaUy CGP 44015 A, are complexed with plasmid DNA encoding for either GFP or luciferase expression. The complexes are prepared with different ratios of cationic charge Upid to anionic charge plasmid. The complexes so prepared are administered to RA 1191 isolated human synoviocyte ceUs in culture at a range of doses. After an incubation time, the ceUs are washed and the ceUs are maintained with fresh media. After 24 hours the ceUs are assayed for GFP expression by flow cytometry and fluorescent microscopy. The results are summarized in Table 15 and Figure 29. These results demonstrate that novel coUoidal vectors provide deUvery and high levels of expression in human synoviocytes. The high efficiency is both a high percentage of ceUs transfected and a high level of protein expression. The function of the vector to generate protein expression is optimized by adjustment of the charge ratio and dose. Table 15: Synoviocytes are thought to be involved in the pathogenesis of rheumatoid arthritis (see e.g. Pap T, Gay RE, Gay S. 2000. Curr Opin Rheumatol 2000 May;12(3):205-10; Haidi Zhang, Yiping Yang, Jennifer L. Horton, Elena B. SamoUova, Thomas A. Judge, Laurence A. Turka, James M. Wilson, and Youhai Chen. 1997. J. Clin. InvestVolume 100, Number 8, October 1951-1957; Yao Q, Glorioso JC, Evans CH, Robbins PD, et al. 2000. J Gene Med 2000 May- Jun;2(3):210-9; Evans CH, Rediske JJ, Abramson SB, Robbins PD. 1999. First International meeting on the Gene Therapy of Arthritis and Related Disorders. Bethesda, MD, USA, 2-3 December 1998. Mol Med Today Apr; 5(4): 148-51; Nita I, Ghivizzani SC, Galea-Lauri J, Bandara G, Georgescu HI, Robbins PD, Evans CH . 1996. Arthritis Rheum May;39(5):820-8. Firestein GS, Yeo M, Zvaifler NJ. 1995. J Clin Invest. 1995 Sep;96(3): 1631-8). Thus, in a preferred embodiment of this invention, synoviocytes are targets for the treatment of rheumatoid arthritis with gene therapy methods. Accordingly, the present invention contemplates a method of treatment of rheumatoid arthritis with gene therapy, wherein a vector of the invention comprising a therapeutic gene is administered to a patient in an effective amount, and wherein said therapeutic gene is preferentiaUy deUvered to synoviocytes. Efficacy can be determined by study of the ameUoration of one or more symptoms of the disease. Advantageously, the in vivo efficacy can use measurement of defined clinical end points that are characteristic of the progress or extent of rheumatoid arthritis. The exact dosage to be administered is dependent upon a variety of factors including the age, weight, and sex of the patient, and the severity of the condition being treated. Such administration may be by systemic administration or by direct injection of the vectors into tissue or cavities that are affected by rheumatoid arthritis. The vectors also may be administered in conjunction with an acceptable pharmaceutical carrier. The selection of a suitable pharmaceutical carrier is deemed to be apparent to those skiUed in the art. Example 56. Colloid vector with RGD peptide - Gene delivery to and expression by human synoviocytes. A further improvement with surface exposed Ugands is Ulustrated from studies whereby an RGD peptide is incorporated into the novel coUoid vector. Complexes with and without the RGD peptide are prepared at different charge ratios and tested for transfection of RA 1911 ceUs as described in Example 55. The results are shown in Figure 30. The results demonstrate that addition of Ugands decreases the dependence of gene expression on cationic surface charge. At a charge ratio of 0.4 the surface charge is derived from an excess of negative charges in the complex yet when this charge ratio coUoid vector contains the RGD Ugand the vector remains as active as that without a Ugand and have a charge ratio giving a positive charge. SimUar results are obtained using novel coUoids prepared with RGD peptide Ugands conjugated to PEG modified polycation agents prepared according to the invention. When coUoid preparations are prepared with and without the RGD peptide Ugand the expression is dependent upon presence of the Ugand. _(: * * * =_: # The invention has been disclosed broadly and Ulustrated in reference to representative embodiments described above. Those skiUed in the art wUl recognize that various modifications can be made to the present invention without departing from the spirit and scope thereof.

Claims: WHAT IS CLAIMED IS: 1. A non-naturaUy occurring gene therapy vector comprising an inner sheU comprising (1) a core complex comprising a nucleic acid and (2) at least one complex forming reagent. 2. A vector according to claim 1 , further comprising a fusogenic moiety. 3. A vector according to claim 2, wherein said fusogenic moiety comprises a sheU that is anchored to said core complex. 4. A vector according to claim 2, wherein said fusogenic moiety is incorporated directly in said core complex. 5. A vector according to claim 1, further comprising an outer sheU moiety that stabilizes said vector and reduces nonspecific binding to proteins and ceUs. 6. A vector according to claim 5, wherein said outer sheU moiety comprises a hydrophiUc polymer. 7. A vector according to claim 5, further comprising a fusogenic moiety. 8. A vector according to claim 7, wherein said outer sheU moiety is anchored to said fusogenic moiety. 9. A vector according to claim 7, wherein said outer sheU moiety is anchored to said core complex. 10. A vector according to claim 5, comprising a mixture of at least two outersheU reagents. 11. A vector according to claim 10, wherein each of said outersheU reagents comprises a hydrophiUc polymer that reduces nonspecific binding to proteins and ceUs, and wherein said polymers have substantiaUy different sizes. 12. A vector according to claim 1, further compring a targeting moiety that enhances binding of said vector to a target tissue and ceU population. 13. A vector according to claim 5, wherein said outer sheU comprises a targeting moiety that enhances binding of said vector to a target tissue and ceU population. 14. A vector according to claim 1 , wherein said complex-forming reagent is selected from the group consisting of a Upid, a polymer, and a spermine analogue complex. 15. A vector according to claim 1, wherein said complex-forming reagent is a Upid selected from the group consisting of the Upids shown in Figures 2.1 and 2.2. 16. A vector according to claim 15, wherein said complex-forming Upid agent is selected from the group consisting of phosphatidylcholine (PC), phosphatidylethanolamine (PE), dioleoylphosphatidylethanolamine (DOPE), dioleoylphosphatidylcholine (DOPC), cholesterol and other sterols, N-l-(2,3- dioIeyloxy)propyl-N,N,N-trimethylammonium chloride (DOTMA), 1,2-bis (oleoyloxy)-3-(trimethylammonia) propane (DOTAP), phosphatidic acid, phosphatidylglycerol, phosphatidylinositol, glycoUpids comprising two optionaUy unsaturated hydrocarbon chains containing about 14-22 carbon atoms , sphingomyelin, sphingosine, ceramide , terpenes, cholesterol hemisuccinate, cholesterol sulfate, diacylglycerol, 1, 2-dioleoyl-3-dimethylammoniumpropanediol (DODAP), dioctadecyldimethylammonium bromide (DODAB), dioctadecyldimethylammonium chloride (DODAC), dioctadecyIamidoglycylspermine (DOGS), l,3-dioleoyloxy-2-(6- carboxyspermyl)propylamide (DOSPER), 2,3-dioleyloxy-N-[2- (sperminecarboxaιnido)ethyl]-N,N-dimethyl -1-propanaminium trifluoroacetate (DOSPA or Lipofectamine7), hexadecyltrimethyl-ammonium bromide (CTAB), dimethyl-dioctadecylammonium bromide (DDAB), 1, 2-dimyristyloxypropyl-3- dimethyl-hydroxy ethyl ammonium bromide (DMRDB), dipahnitoylphosphatidylethanolamylspermine (DPPES), dioctylamineglycine- spermine (C8Gly-Sper), dihexadecylamine-spermine (C18-2-Sper), ammocholesterol-spermine (Sper-Chol), l-[2-(9(Z)-octadecenoyloxy)ethyl]-2- (8(Z)-heptadecenyl)-3-(2-hydroxyethyl)imidazolinium chloride (DOTIM), dimyristoyl-3-trimethylammonium-propane (DMTAP), 1.2-dimyristoyl-sn-glycero- 3-ethylphosphatidylchoUne (EDMPC or DMEPC), lysylphosphatidylethanolamine (Lys-PE), cholestryl-4-aminoproprionate (AE-Chol), spermadine cholestryl carbamate (Genzyme-67), 2-(dipalmitoyl-l,2-propandiol)-4-methylimidazole (DPIm), 2-(dioleoyl-l,2-propandiol)-4-methyUmidazole (DOIm), 2-(cholestryl-l- propylamine carbamate)imidazole (Chlm), N-(4-pyridyl)-dipalmitoyl-l,2- propandiol-3-amine (DPAPy), 3β-[N-(N',N'- dimethylaminoethane)carbamoyl]cholesterol (DC-Choi), 3β-[N-(N',N',N- trimethylaminoethane)carbamoyl] cholesterol (TC-CHOL-gamma-d3), 1,2- dioleoyl-sn-glycero-3-succinate, l,2-dioleoyl-sn-glycero-3-succinyl-2-hydroxethyl disulfide ornithine conjugate (DOGSDSO), l,2-dioleoyl-sn-glycero-3-succinyl-2- hydroxethyl hexyl orithine conjugate (DOGSHDO), N^N^N^tetramethyl- N,N I ,N π ,N ιπ -tetrapalnUtyolsρermine (TM-TPS), 3-tetradecylamino-N-tert-butyl-N- tetradecylpropionamidine (vectamidine or diC14-amidine), N-[3-[2-(l,3- dioleoyloxy)propoxy-carbonyl]propyl]-N,N,N-trimethyla mmonium iodide (YKS- 220), and 0,0 -Ditetradecanoyl-N-(alpha-trimethylammonioacetyl)diethan olamine chloride (DC-6-14). 17. A vector according to claim 14, wherein said complex forming reagent is a compound of formula I wherein m is 3 or 4; Y signifies a group -(CH 2 )„-, in which n is 3 or 4, or may also signify a group -(CH 2 ) n- , in which n is an integer from 5 to 16, or may also signify a group -CH 2 -CH=CH-CH 2 -, if R 2 is a group -(CH 2 ) 3 -NR 4 R 5 and m is 3; R 2 is hydrogen or lower alkyl or may also signify a group -(CH 2 ) 3 -NR R 5 if m is 3; R 3 is hydrogen or alkyl or may also signify a group -CH 2 -CH(-X)-OH, if R 2 is a group -(CHkb-N jRs and m is 3; X and X', independently of one another, signify hydrogen or alkyl; the radicals R, R l5 R4 and R5, independently of one another, are hydrogen or lower alkyl; with the proviso that the radicals R, R R 2 , R 3 and X cannot aU together signify hydrogen or methyl, if m is 3 and Y signifies a group -(CH 2 ) 3 -; and their pharmaceuticaUy acceptable salts. 18. A vector according to claim 14, wherein said complex foπning reagent comprises a mixture of at least two complex forming reagents. 19. A vector according to claim 1 , wherein said complex forming reagent possesses one or more additional activities selected from the group consisting of ceU binding, biological membrane fusion, endosome disruption, and nuclear targeting. 20. A vector according to claim 1, wherein said nucleic acid is selected from the group consisting of a recombinant plasmid, a repUcation-deficient plasmid, a mini-plasmid, a recombinant viral genome, a Unear nucleic acid fragment, an antisense agent, a Unear polynucleotide, a circular polynucleotide, a ribozyme, a ceUular promoter, and a viral genome. 21. A vector according to claim 1 , wherein the core complex further comprises a nuclear targeting moiety that enhances nuclear binding and/or uptake. 22. A vector according to claim 21 , wherein said nuclear targeting moiety is selected from the group consisting of a nuclear localization signal peptide, a nuclear membrane transport peptide, and a steroid receptor binding moiety. 23. A vector according to claim 21 , wherein said nuclear targeting moiety is anchored to the nucleic acid in said core complex. 24. A vector according to claim 2, wherein said fusogenic moiety comprises at least one moiety selected from the group consisting of a viral peptide, an amphiphiUc peptide, a fusogenic polymer, a fusogenic polymer-Upid conjugate, a biodegradable fusogenic polymer, and a biodegradable fusogenic polymer-Upid conjugate. 25. A vector according to claim 24, wherein said fusogenic moiety is a viral peptide selected from the group consisting of MLV env peptide, HA env peptide, a viral envelope protein ectodomain, a membrane-destabilizing peptide of a viral envelope protein membrane-proximal domain, a hydrophobic domain peptide segment of a viral fusion protein, and an amphiphilic-region containing peptide, wherein said amphiphiUc-region containing peptide is selected from the group consisting of meUttin, the magainins, fusion segments from H. influenza hemagglutinin (HA) protein, HIV segment I from the cytoplasmic taU of HIV1 gp41, and amphiphiUc segments from viral env membrane proteins. 26. A vector according to claim 1, wherein said complex forming reagent is a polymer having the structure: wherein RI and R3 independently are a hydrocarbon or a hydrocarbon substituted with an amine, guanidinium, or imidazole moiety, wherein RI and R3 can be identical or different; and R2 is a lower alkyl group. 27. A vector according to claim 1 , wherein said complex forming reagent is a polymer having the structure: wherein Rl and R3 independently are a hydrocarbon or a hydrocarbon substituted with an amine, guanidinium, or imidazole moiety, wherein Rl and R3 can be identical or different; and R2 and R4 independently are lower alkyl groups. 28. A vector according to claim 2, wherein said fusogenic moiety is a polymer having the structure: wherein Rl is a hydrocarbon or a hydrocarbon substututed with an amine, guanidinium, or imidazole moiety; R2 is a lower alkyl group; and R3 is a hydrocarbon or a hydrocarbon substututed with a carboxyl, hydroxyl, sulfate, or phosphate moiety. 29. A vector according to claim 2, wherein said fusogenic moiety is a polymer having the structure: wherein Rl is a hydrocarbon or a hydrocarbon substututed with an amine, guanidinium, or imidazole moiety; R2 and R4 independently are lower alkyl groups, and R3 is a hydrocarbon or a hydrocarbon substituted with a carboxyl, hydroxyl, sulfate, or phosphate moiety. 30. A vector according to claim 2, wherein said fusogenic moiety is a membrane surfactant polymer-Upid conjugate. 31. A vector according to claim 30, wherein said membrane surfactant polymer-Upid conjugate is selected from the group consisting of Thesit™, Brij 58™, Brij 78™, Tween 80™, Tween 20™, C 12 E 8 , d 6 E 8 (C n E n = hydrocarbon poly(ethylene glycol) ether where C represents hydrocarbon of carbon length N and E represents poly(ethylene glycol) of degree of polymerization N), Chol-PEG 900, analogues containing polyoxazoUne or other hydrophUic polymers substituted for the PEG, and analogues having fluorocarbons substituted for the hydrocarbon. 32. A vector according to claim 5, wherein said inner sheU is anchored to said outer sheU moiety via a covalent linkage that is degradable by chemical reduction or sulfhydryl treatment. 33. A vector according to claim 32, wherein said inner sheU is anchored to said outer sheU moiety via a covalent linkage that is degradable at a pH of 6.5 or below. 34. A vector according to claim 33, wherein said covalent linkage is selected from the group consisting of 35. A vector according to claim 5, wherein said outer sheU comprises a protective polymer conjugate where the polymer exhibits solubiUty in both polar and non-polar solvents. 36. A vector according to claim 5, wherein said outer sheU comprises a protective steric polymer conjugate where the polymer is selected from the group consisting of PEG, a polyacetal polymer, a polyoxazoUne, a polyoxazoUne polymer block with end-group conjugation, a hydrolyzed dextran polyacetal polymer, a polyoxazoUne, a polyethylene glycol, a polyvinylpyrroUdone, polylactic acid, polyglycoUc acid, , polymethacrylamide, poIyethyloxazoUne, polymethyloxazoUne, polydimethylacrylamide, polyvinylmethylether, polyhydroxypropyl methacrylate, polyhydroxypropylmethacrylamide, polyhydroxyethyl acrylate, polyhydroxyethyloxazoUne, polyhydroxypropyloxazoUne and polyaspartamide, and a polyvinyl alcohol. 37. A vector according to claim 13, wherein said targeting element is a receptor Ugand, an antibody or antibody fragment, a targeting peptide, a targeting carbohydrate molecule or a lectin. 38. A vector according to claim 37, wherein said targeting element is selected from the group consisting of vascular endotheUal ceU growth factor, FGF2, somatostatin and somatostatm analogs, transferrin, melanotropin, ApoE and ApoE peptides, von WiUebrand's Factor and von WiUebrand's Factor peptides; adenoviral fiber protein and adenoviral fiber protein peptides; PD1 and PD1 peptides, EGF and EGF peptides, RGD peptides, folate, pyridoxyl, and sialyl- Lewis x and chemical analogues. 39. A compound having the formula I wherein m is 3 or 4; Y signifies a group -(CH 2 ) n -, in which n is 3 or 4, or may also signify a group -(CH 2 ) n -, in which n is an integer from 5 to 16, or may also signify a group -CH 2 -CH=CH-CH 2 -, if R 2 is a group -(CH 2 ) 3 -NR 4 R 5 and m is 3; R 2 is hydrogen or lower alkyl or may also signify a group -(CH 2 ) 3 -NR R 5 if m is 3; R 3 is hydrogen or alkyl or may also signify a group -CH ∑ -CHt-X -OH, if R 2 is a group -(CH 2 ) 3 -NR R 5 and m is 3; X and X', independently of one another, signify hydrogen or alkyl; and the radicals R, Ri, R 4 and R 5 , independently of one another, are hydrogen or lower alkyl; with the proviso that the radicals R, R R 2 , R 3 and X cannot aU together signify hydrogen or methyl, if m is 3 and Y signifies a group -(CH2) 3 -; and their pharmaceutically acceptable salts. 40. A pharmaceutical composition comprising a vector according to claim 1, together with a pharmaceuticaUy acceptable dUuent or excipient. 41. A method for foπning a self-assembling core complex according to claim 1, comprising the step of feeding a stream of a solution of a nucleic acid and a stream of a solution of a core complex-forming moiety into a static mixer, wherein the streams are spUt into inner and outer heUcal streams that intersect at several different points causing turbulence and thereby promoting mixing that results in a physicochemical assembly interaction. 42. A method of treating a disease in a patient, comprising administering to said patient a therapeutically effective amount of a vector according to claim 1. 43. A non-naturaUy occurring gene therapy vector comprising an inner sheU comprising: (1) a core complex comprising a nucleic acid and at least one complex forming reagent; (2) a nuclear targeting moiety; (3) a fusogenic moiety; and (4) an outer sheU comprising (i) a hydrophUic polymer that stabilizes said vector and reduces nonspecific binding to proteins and cells and (n) a tageting moiety that provides binding to target tissues and cells, wherein said outer sheU is linked via a cleavable linkage that enables the outer sheU to be shed. 44. A vector according to claim 1 wherein said vector displays biological activity. 45. A vector according to claim 1 wherein said vector displays fusogenic activity.

Inventors: CHENG CHENG, FREI JOERG, METT HELMUT, PUTHUPPARAMPIL SCARIA, STANEK JAROSLAV, SUBRAMANIAN KAS, TITMAS RICHARD, WOODLE MARTIN, YANG JINGPING, CHENG, CHENG, FREI, JOERG, METT, HELMUT, PUTHUPPARAMPIL, SCARIA, STANEK, JAROSLAV, SUBRAMANIAN, KAS, TITMAS, RICHARD, WOODLE, MARTIN, YANG, JINGPING
Applicants: CHENG CHENG, FREI JOERG, METT HELMUT, NOVARTIS AG, NOVARTIS ERFIND VERWALT GMBH, PUTHUPPARAMPIL SCARIA, STANEK JAROSLAV, SUBRAMANIAN KAS, TITMAS RICHARD, WOODLE MARTIN, YANG JINGPING, CHENG, CHENG, FREI, JOERG, METT, HELMUT, NOVARTIS-ERFINDUNGEN VERWALTUNGSGESELLSCHAFT M.B.H., PUTHUPPARAMPIL, SCARIA, STANEK, JAROSLAV, SUBRAMANIAN, KAS, TITMAS, RICHARD, WOODLE, MARTIN, YANG, JINGPING
Application year: 2000
Main classification: A61K48
IPC codes: A61K9, A61K31, A61K38, A61K39, A61K47, A61K48, A61P43, C07C215, C12N15