bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of oleic acid surface coating on the properties of nickel ferrite nanoparticles/PLA composites
Authors: Yin Hong , Chow Gan‐Moog 
Published: November 2008

AbstractNickel ferrite nanoparticles with or without oleic acid surface coating were mixed with poly(D,L‐lactide) (PLA) by double emulsion method. If the nanoparticles were prepared without oleic acid coating, they adsorbed on the PLA surface. If the nanoparticles were coated with oleic acid, they could be readily encapsulated within the PLA microspheres. A slight depression in glass transition temperature was found in all composites and it could be related to the interfacial energies between nanoparticles and PLA. Optimum mixed composite was achieved by reducing interfacial energy. However, loading capacity was limited in this composite. Increasing the amount of nickel ferrite nanoparticles was not useful to increase loading capacity. Cytotoxicity of the composite decreased significantly when nickel ferrite nanoparticles were effectively encapsulated in PLA microspheres. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Polypyrrole‐polysaccharide thin films characteristics: Electrosynthesis and biological properties
Authors: Serra Moreno Judith , Panero Stefania , Materazzi Stefano , Martinelli Andrea , Sabbieti Maria Giovanna , Agas Dimitrios , Materazzi Giovanni 
Published: November 2008

AbstractPolypyrrole‐polysaccharide thin films were electropolymerized from starting solutions containing pyrrole and a polysaccharide, namely, heparin, chondroitin‐4‐sulphate or hyaluronic acid. The synthesized samples showed good chemical and physicochemical properties determined by the synthesis parameters such as the current density and time. For instance, the sample morphology was strictly correlated to the current density as follows: a smooth surface morphology was observed when the current density was in the range of 100–700 μA/cm2, whereas high current (I > 1.0 mA/cm2) or longer time (synthesis charge > 100 mC/cm2) led to rough surfaces. The presence of polysaccharide within the polymeric matrix assured proper hydrophilicity to the samples. The optimized surface chemistry due to the presence of a polysaccharide and the controllable morphology allowed positive cell/substrate interactions and these are proved by cellular tests using MC3T3‐E1 osteoblast cultures. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Effect of maghemite nanoparticles on insulin amyloid fibril formation: Selective labeling, kinetics, and fibril removal by a magnetic field
Authors: Skaat Hadas , Sorci Mirco , Belfort Georges , Margel Shlomo 
Published: November 2008

AbstractMaghemite (γ‐Fe2O3) magnetic nanoparticles of 15.0 ± 2.1 nm were formed by nucleation followed by controlled growth of maghemite thin films on gelatin‐iron oxide nuclei. Human insulin amyloid fibrils were formed by incubating the monomeric insulin dissolved in aqueous continuous phase at pH 1.6 and 65°C. Magnetic human insulin amyloid fibrils/γ‐Fe2O3 nanoparticle assemblies were prepared by interacting the γ‐Fe2O3 nanoparticles with the insulin amyloid fibrils during or after their formation. The nanoparticles attached selectively to the insulin fibrils in both cases. The kinetics of the insulin fibrillation process in the absence and the presence of the γ‐Fe2O3 nanoparticles was elucidated. The insulin amyloid fibrils/γ‐Fe2O3 nanoparticle assemblies were easily extracted from the aqueous phase via a magnetic field. We hypothesize that this selective extraction approach may also be applicable for the removal of other amyloidogenic proteins that lead to neurodegenerative diseases (e.g., Alzheimer's, Parkinson's, Huntington's, mad cow, and prion diseases) from their continuous phase, e.g. milk, blood, neurological fluid, etc. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Rare earth metals used in biodegradable magnesium‐based stents do not interfere with proliferation of smooth muscle cells but do induce the upregulation of inflammatory genes
Authors: Drynda Andreas , Deinet Nicole , Braun Nicole , Peuster Matthias 
Published: November 2008

AbstractRare earth metals are added to corrodible magnesium‐based alloys in low amounts (up to 10%) to improve their mechanical properties and to decrease the degradation rate. Cerium (Ce), neodymium (Nd), yttrium (Y), and ytterbium (Yb) are already used for degradable cardiovascular stents. Little is known about the biocompatibility of rare earth metals released during the degradation process of the implant. Therefore the biocompatibility of rare earth metals was assessed with regard to metabolic activity of human vascular smooth muscle cells (SMCs). After coincubation with the trivalent chlorides (0.5–100 μg/mL) of rare earth metals for 24, 72, 144, and 240 h metabolic activity was determined at each time point using the colometric WST‐1 test. The tested rare earth metals did not lead to significant changes in metabolic activity over a wide concentration range. However, at high concentrations a decrease was observed. Apoptotic or necrotic effects were not observed. Furthermore, we analyzed the effects of Ce, Nd, Y, and Yb on the expression of genes involved in inflammatory processes. The expression of IL‐6, IL‐8, and ICAM‐1 in SMCs after exposure to Ce, Nd, Y, and Yb (5 and 50 μg/mL) was measured using quantitative real‐time PCR. Significant up‐regulation of IL‐6, IL‐8, and ICAM‐1 genes were only found after 24 h, mainly for a concentration of 50 μg/mL. Our cell culture data indicate that rare earth metals influence cellular processes of vascular cells. Whether adverse effects occur also in in vivo is the topic of further investigations. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Triggered release of small molecules from proteinoid microspheres
Authors: Quirk Stephen 
Published: November 2008

AbstractProteinoid microspheres (PM) are formed by the thermal condensation of amino acids. They have been useful to further evolutionary theory, as catalysts for some biochemical reactions, but they have not been overly useful as controlled delivery agents. It is possible however to construct PMs that contain organic small molecules in the interior space. This means that a PM could be used as a delivery agent, if a suitable method could be discovered to cause the release of the internal material. This report describes the formation of a PM that includes a molecular bridging agent that can be removed in a reducing environment. Removal of the bridge opens a hole or window in the PM that allows the interior material to escape. The rate at which the interior material is released from the PM can be controlled by the size of the window or by the reduction potential in the environment. These PMs can be used to temporally treat a variety of complications including wounds (chronic or acute) by delivering a sequestered reagent in a controlled manner and are advantageous in that amino acids are the primary delivery vehicle breakdown product. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Culture of skeletal muscle cells in unprecedented proximity to a gold surface
Authors: Coletti Dario , Scaramuzzo Francesca A. , Montemiglio Linda C. , Pristerà Alessandro , Teodori Laura , Adamo Sergio , Barteri Mario 
Published: November 2008

AbstractCulturing of skeletal muscle cells on conductive surfaces is required to develop electronic device–muscle junctions for tissue engineering and medical applications. We characterized from a molecular and morphological point of view myogenic cells cultured on gold and on cysteamine‐coated gold, as compared to the standard plastic for cell culture. Our results show that cell proliferation and survival are comparable between cells grown on either of the gold surface or plastic. The majority of the cells cultured on gold surfaces retain the ability to respond to differentiation cues, as shown by nuclear translocation of myogenin. Following terminal differentiation, the myotubes cultured on cysteamine‐coated gold resemble myotube cultures obtained on plastic for the size and orientation of the myotube bundles retaining most of myosin expression; on the contrary, the myotube cultures on gold show a clumped morphology, likely due to repulsive cell‐substratum interaction resulting in aberrant differentiation. On the basis of the aforementioned evidences, the culture of muscle cells on cysteamine‐coated gold represents an advance with respect to previously reported substrata. The cysteamine self‐assembled monolayer coating is a simple approach to accomplish cultures of myotubes in unprecedented tight proximity to conductive surfaces. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Smooth muscle cell adhesion in surface‐modified three‐dimensional copolymer scaffolds prepared from co‐continuous blends
Authors: Bramfeldt Hanna , Sarazin Pierre , Vermette Patrick 
Published: November 2008

AbstractIn this article, tissue‐engineering scaffolds were fabricated from P(ϵ‐CL‐co‐D,L‐LA)‐PEG‐P(ϵ‐CL‐co‐D,L‐LA) copolymers using co‐continuous blends with polystyrene as the porogen phase. By means of static annealing and following extraction of the porogen phase, pore sizes (channel widths) in the range of 15–350 μm were obtained. Smooth muscle cells were seeded in three‐dimensional fibronectin‐modified scaffolds of two different pore sizes. Considerably enhanced cell seeding efficiency was found for scaffolds with larger pore sizes, indicating the importance of this parameter to promote effective cell intrusion into bulk materials. Compressive moduli ranged from 2.3 ± 0.3 to 67 ± 15 MPa and decreased with increasing pore size. The reverse trend was found for scaffold permeability (κ), which ranged from 8.5 × 10−16 to 6.7 × 10−11 m2. This was comparable with permeabilities previously reported for scaffolds with higher pore sizes and void volumes, but more irregular pore morphologies. Taken together, the results obtained in this study motivate further investigation for possible future applications in tissue engineering. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Cocultures of osteoblasts and osteoclasts are influenced by local application of zoledronic acid incorporated in a poly(D,L‐lactide) implant coating
Authors: Greiner S. , Kadow‐Romacker A. , Schmidmaier G. , Wildemann B. 
Published: November 2008

AbstractThe antiresorptive activity of bisphosphonates such as zoledronic acid (ZOL) has been shown in vitro to be because of their effect on osteoclasts and osteoblasts. However, whether the effect of ZOL on monocultures might be reproducible on cocultures and whether cell interactions might influence this effect has not been described. The aim of the study was to investigate the effect of ZOL on cocultures of osteoblasts and osteoclasts in vitro. ZOL was incorporated in an implant coating based on poly(D,L‐lactide) in different concentrations (10–50 μM). Cell number was measured, and procollagen I synthesis, osteoprotegerin (OPG) secretion and soluble receptor activator of nuclear factor‐κB ligand (sRANKL) were analyzed. Moreover, TRAP‐positive cells and resorption lacunas on dentin chips were counted. Results showed that cell viability was not affected when treated with doses equivalent up to 50‐μM ZOL‐coated implants (ZOL‐CI). Procollagen I and OPG synthesis was highest when treated with 10 μM ZOL‐CI, whereas sRANKL showed no significant decrease when treated with the investigated concentrations of ZOL‐CI. TRAP‐positive cells were decreased when treated with ZOL‐CI in a dose‐dependent manner. Resorption activity of osteoclasts was not significantly decreased when treated with investigated concentrations of ZOL‐CI. Exposure to specific concentrations of ZOL‐CI showed a beneficial effect on osteoblast differentiation and protein synthesis. Formation of osteoclast was decreased, whereas a significant decrease in sRANKL secretion and resorption activity of osteoclasts could not be shown. The investigated effect on cocultures might be clinically useful to support fracture healing and to reduce orthopedic implant loosening. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Increased osteoblast functions in the presence of BMP‐7 short peptides for nanostructured biomaterial applications
Authors: Chen Yupeng , Webster Thomas J. 
Published: November 2008

AbstractTo improve bone regeneration around orthopedic biomaterials, researchers have attempted to combine growth factors on and in implants. Equally as exciting, greater bone growth has been demonstrated around nanoscaled materials (like helical rosette nanotubes or nanocrystalline hydroxyapatite) that mimic the geometry of the natural components of bone. To combine these two approaches, in this in vitro study, the ability of three short peptides [labeled for convenience: a or SNVILKKYRN, b or KPSSAPTQLN, and c or KAISVLYFDDS chosen from the larger bone morphogenetic protein‐7 (BMP‐7)] to promote osteoblast (bone‐forming cells) functions were determined. Shorter peptides of BMP‐7 are required for growth factor incorporation into nanoscale biomaterials because their sizes are in the nanometer regime. Results showed that of all the peptides, peptide b and the peptide combination a,b, enhanced osteoblast density the most after 5 days when compared with the controls (no growth factors). Furthermore, osteoblasts cultured with peptide b had a larger and more spread morphology than did controls. In addition, peptide c and its combinations (a, c; b, c; and a, b, c) increased osteoblast calcium deposition after 14 and 21 days compared with the controls. Since these peptides are much smaller than BMP‐7, the results of this study provided information that peptides can be easily chemically functionalized onto nanoscaled biomaterials to improve bone growth. Thus, the present study elucidated that shorter peptides in BMP‐7 was found to be more appropriate for inclusion in and on nanomaterials to promote osteoblast proliferation (peptide b and the peptide combination a,b) and osteoblast deposition of calcium‐containing mineral (peptide c and the peptide combinations a,c; b,c; and a, b, c). © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
PEGylation strategies for active targeting of PLA/PLGA nanoparticles
Authors: Betancourt Tania , Byrne James D. , Sunaryo Nicole , Crowder Spencer W. , Kadapakkam Meena , Patel Shefali , Casciato Shelly , Brannon‐Peppas Lisa 
Published: November 2008

AbstractThis work evaluates various techniques for the incorporation of poly(ethylene glycol) (PEG) onto biodegradable nanoparticles (NPs) of poly(lactic‐co‐glycolic acid) (PLGA) or poly(lactic acid) (PLA) with the purpose of providing a functional site for surface conjugation of targeting agents and for improving surface properties. The techniques compared were based on NP preparation with blends of PLGA and poloxamer or with block copolymers of PLGA/PLA with PEG. Blending of PLGA with poloxamer 407 resulted in the incorporation of the latter to up to a 43 wt % content. Direct conjugation of heterofunctional NH2‐PEG‐COOH to the surface of premade NPs was not highly effective. Preparation of copolymers of PLGA with PEG was determined to be more effective and versatile by polymerization of lactide and glycolide dimers onto the hydroxyl group of heterofunctional OH‐PEG‐COOH than by conjugation of the premade polymers with carbodiimide chemistry. NPs prepared with these copolymers confirmed the surface localization of PEG and proved to be useful for conjugation of mouse immumoglobulin as a model targeting agent. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Characterization of interfacial chemistry of adhesive/dentin bond using FTIR chemical imaging with univariate and multivariate data processing
Authors: Wang Yong , Yao Xiaomei , Parthasarathy Ranganathan 
Published: November 2008

AbstractFourier transform infrared (FTIR) chemical imaging can be used to investigate molecular chemical features of the adhesive/dentin interfaces. However, the information is not straightforward and is not easily extracted. The objective of this study was to use multivariate analysis methods, principal component analysis, and fuzzy c‐means clustering and to analyze spectral data in comparison with univariate analysis. The spectral imaging data collected from both the adhesive/healthy dentin and adhesive/caries‐affected dentin specimens were used and compared. The univariate statistical methods such as mapping of intensities of specific functional group do not always accurately identify functional group locations and concentrations because of more or less band overlapping in adhesive and dentin. Apart from the ease with which information can be extracted, multivariate methods highlight subtle and often important changes in the spectra that are difficult to observe using univariate methods. The results showed that the multivariate methods gave more satisfactory, interpretable results than univariate methods and were conclusive in showing that they can discriminate and classify differences between healthy dentin and caries‐affected dentin within the interfacial regions. It is demonstrated that the multivariate FTIR imaging approaches can be used in the rapid characterization of heterogeneous, complex structure. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
A novel biocompatible adhesive incorporating plant‐derived monomers
Authors: Klapperich Catherine M. , Noack Cassandra L. , Kaufman Jessica D. , Zhu Lin , Bonnaillie Laetitia , Wool Richard P. 
Published: November 2008

AbstractWe describe a new class of biomaterials with potential for a variety of applications in tissue engineering, wound healing, and transdermal drug delivery. These materials are based on oleic methyl ester (OME), which is derived from various plant oils including soybean oil. The OME was acrylated (AOME) and subsequently copolymerized with methyl methacrylate (MMA) and ethylene glycol dimethacrylate (EGDMA) to form pressure sensitive adhesives (PSAs). We assessed the cytocompatibility of each PSA product using Alamar Blue and Live/Dead assays. It was found that after 2 h, human fibroblast cells attached on all four of the PSA polymers tested. After 24 h, cell spreading was seen on all materials with the exception of the polymerized AOME product (PAOME). Cells attached to the copolymer PSA products continued to proliferate for up to 2 weeks, as shown by fluorescent confocal microscopy imaging. Finally, a mechanical analysis of each of the copolymers is presented demonstrating that they have a range of mechanical properties and cell adhesiveness depending on the formulation, making them attractive candidates for use as bioactive adhesives. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Stem cells in development of therapeutics for Parkinson's disease: A perspective
Authors: Xi Jiajie , Zhang Su‐Chun 
Published: November 2008

AbstractUsing Parkinson's disease as a prototype of neurodegenerative diseases, we propose applications of human stem cells in the development of therapeutics for neurodegenerative diseases. First, in vitro differentiation of human stem cells offers a versatile model for dissecting molecular interactions underlying human dopamine (DA) neuron specification, which may form a foundation for instigating regeneration of DA neurons from progenitors that reside in the brain. Second, stem cells derived from diseased cells or through genetic modification can serve as a platform for unraveling biochemical processes that lead to the cellular pathogenesis of degeneration. This may in turn serve as a template for identifying or developing therapeutics for slowing, stopping, or reversing the disease process. And finally, stem cells, particularly those induced from patients' own cells, provide a reliable source of DA neurons for cell‐based therapy. J. Cell. Biochem. 105: 1153–1160, 2008. © 2008 Wiley‐Liss, Inc.
TGF‐β1 induces rearrangement of FLK‐1–VE‐cadherin–β‐catenin complex at the adherens junction through VEGF‐mediated signaling
Authors: Cook Brandoch D. , Ferrari Giovanni , Pintucci Giuseppe , Mignatti Paolo 
Published: November 2008

AbstractVEGF and TGF‐β1 induce angiogenesis but have opposing effects on vascular endothelial cells: VEGF promotes survival; TGF‐β1 induces apoptosis. We have previously shown that TGF‐β1 induces endothelial cell apoptosis via up‐regulation of VEGF expression and activation of signaling through VEGF receptor‐2 (flk‐1). In context with TGF‐β1, VEGF signaling is transiently converted from a survival into an apoptotic one. VEGF promotes cell survival in part via activation of PI3K/Akt by a mechanism dependent on the formation of a multi‐protein complex that includes flk‐1 and the adherens junction proteins VE‐cadherin and β‐catenin. Here we report that TGF‐β1 induces rearrangement of the adherens junction complex by separating flk‐1 from VE‐cadherin and increasing β‐catenin association with both flk‐1 and VE‐cadherin. This rearrangement is caused neither by changes in adherens junction mRNA or protein expression nor by post‐translational modification, and requires VEGF signaling through flk‐1. These results show that the adherens junction is an important regulatory component of TGF‐β1–VEGF interaction in endothelial cells. J. Cell. Biochem. 105: 1367–1373, 2008. © 2008 Wiley‐Liss, Inc.
HDL3 reduces the association and modulates the metabolism of oxidized LDL by osteoblastic cells: A protection against cell death
Authors: Brodeur Mathieu R. , Brissette Louise , Falstrault Louise , Moreau Robert 
Published: November 2008

AbstractOxidized low density lipoproteins (OxLDL) are known to promote atherosclerosis, but it is only recently that OxLDL have been associated with alterations of the functions of bone‐forming osteoblasts and osteoporosis. Although high density lipoproteins (HDL) are recognized for their anti‐atherogenic action, there is less information about their ability to protect against osteoporosis. Therefore, we investigated the capacity of HDL3 to prevent the cell death induced by OxLDL in human osteoblastic cells. Simultaneous exposure of the cells to HDL3 and OxLDL abolished the reduction of cell viability monitored by MTT activity measurement and the induction of apoptosis determined by annexin V staining indicating that HDL3 prevent the apoptosis of osteoblasts induced by OxLDL. This protection correlated with the displacement by HDL3 of OxLDL association to osteoblasts, signifying that OxLDL binding and/or internalization are/is necessary for their cytotoxic effects. We also found that exposition of osteoblastic cells to HDL3 prior to incubation with OxLDL reduced cell death and preserved the lysosomal integrity. This protection was correlated with an increase of SR‐BI expression, a modification of OxLDL metabolism with less global uptake of OxLDL and greater selective uptake of cholesterol from OxLDL. These results strongly suggest that, as for atherosclerosis, HDL may exert beneficial actions on bone metabolism. J. Cell. Biochem. 105: 1374–1385, 2008. © 2008 Wiley‐Liss, Inc.