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Please use this identifier to cite or link to this item: http://hdl.handle.net/1860/73

Title: Peptide-modified polymer for endothelialization
Authors: Ostroha, Jamie Lyn
Keywords: Vascular grafts;Polymers in medicine
Issue Date: 7-Nov-2002
Publisher: Drexel University
Abstract: A functionalized polycarbonate material derived from tyrosine containing varyinglevels of free acid functionality along the backbone, poly(DTE-co-X%DT carbonate), hasbeen functionalized with a peptide to promote endothelial cell attachment and evaluatedas a potential synthetic vascular graft material. Lysine derivatives have been produced topromote the attachment of engineered peptides for promoting endothelialization.NMR has been used to analyze the initial structure of the poly(DTEC-co-X%DTC) and changes in the structure with the attachment of L-lysine ethyl ester andpolylysine, polyalanine, and the (ARKKAAKA)4 peptide. The polymer peak at 4.8 ppmhas been labeled the a-peak. This peak is the primary peak used to evaluate changes inthe spectra related to changing polymer functionality and the attachment of molecules tothe pendant acid group. Changes in the ß-peak (3.05 ppm), the R2 peak (4.1 ppm) and theR3 peak (1.3 ppm) are compared to the a-peak for quantification purposes. Key NMRpeaks have been identified and lysine attachment and quantification is discussed. A lysinepeak has been identified at 4.38 ppm. This peak is also compared to the polymer a-peak,indicating 85-90% attachment efficiency. The use of polylysine, polyalanine, andpeptides establish that peptide binding is successful; qualitative and semi-quantitativeresults are presented. Semi-quantitative results with polyalanine indicate a large degree ofattachment, although some interference with the spectral peaks has been noted.The effect of poly(DTEC-co-X%DTC) on human endothelial cell attachment andgrowth is also studied and compared to current synthetic materials. Cell attachment hasbeen shown to increase significantly as the polymer becomes more hydrophilic. Nonfunctionalizedpolymers show that less than five percent of cells remained attach at aforce of 300 g, while 50% functionalized polymers show 40% attachment at the sameforce. Cell growth studies show an increase in cell affinity with increasing hydophilicity.35% functionalized polymer shows over double the number of cells as the nonfunctionalizedmaterial after seven days. The results for the p(DTEC) at increasing levelsof functionality bracket Dacron and PLA depending. Cell spreading, confluence, anddivision have been confirmed by visual analysis.
URI: http://dspace.library.drexel.edu/handle/1860/73
Appears in Collections:Drexel Theses and Dissertations

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