Patent ID: 7422861

Claim:
A method of identifying peptoids which are effective in transfecting a cell with an oligonucleotide, the method comprising (i) providing a library of peptoids in an array of physically separated compartments, said peptoids having a plurality of different sequences and having the general formula I: where R a is selected from the group consisting of alkyl, aryl, aralkyl, aralkenyl, and aralkynyl, any of which may be substituted with one or more groups X hydrogen, —OH, —SH, —COOH, sulfonyl, and a lipid moiety, wherein said lipid moiety may be conjugated to a linker moiety, each R b is independently selected from the group consisting of alkyl, aryl, aralkyl, aralkenyl, and aralkynyl, any of which may be substituted with one or more groups X; and hydrogen, wherein at least one group R b is not hydrogen; R c is selected from the group consisting of alkyl, aryl, aralkyl, aralkenyl, and aralkynyl, any of which may be substituted one or more groups X; hydrogen, —OH, —SH, —NH 2 , —NHR, —NH(C═O)R, where R is lower alkyl; sulfonyl, hydrazine, and a lipid moiety, wherein said lipid moiety may be conjugated to a linker moiety; X is selected from hydroxy, alkoxy, amino, guanidino, amidino, alkylamino, alkylthio, halogen, nitro, cyano, keto, aldehyde, carboxylic acid, carboxylic ester, carboxylic amide, sulfonic acid and sulfonic ester; at least one of R a and R c comprises a lipid moiety; R 1 and R 2 are independently selected from hydrogen, lower alkyl, and lower alkoxy; and m is an integer selected from 2 to about 50, wherein the sequences of individual peptoids in the library are unidentified; (ii) contacting a plurality of peptoids having unidentified sequences from the library provided in (i) with an oligonucleotide, to form a plurality of peptoid-oligonucleotide mixtures, wherein said oligonucleotide is between about 10 and 50 nucleotides in length, and is a fluorescently labelled or an antisense oligonucleotide, and wherein said contacting is performed in an array of physically separated compartments; (iii) contacting each said mixture with a cell in an array of physically separated compartments; (iv) screening each cell for transfection of the oligonucleotide, to identify transfected cells; and (v) identifying transfecting peptoids in mixtures contacted with transfected cells.