PLLA-PC-PLLA Copolymer Synthsis And Study On Their Properties

Phospholipid polymers are of current hot interests in the field ofbiomaterials. Synthesizing phospholipid analogues, particularly phospholipidspolymers and investigating their properties have attracted much interest andattention since 1982 when the first phosphatidylcholine analogous vinylmonomer, 2-(methacryloyloxy)ethyl-2-(trimethylammonium)ethyl phosphatewas reported. All phospholipid polymers reported can be classifieded into twotypes, side chain type and main chain type from the viewpoint of molecularstructure. The introduction of polymerizable vinyl group into phospholipidanalogues is one of the most often used approaches to synthesize side chain typephospholipid polymers. However, phospholipid polymers obtained by thisapproach can not be degraded.Poly(L-lactide)s have been widely used in the field of biomedicalmaterials due to their excellent mechanical properties, low immunogenicity andgood biocompatibility. However, these biodegradable polymers represent thenonspecific protein adsorption for the application of drug delivery systems orantiadhesive membranes, and the lack of functional groups, which serve as cellrecognition sites for cell attachment.In this work, we synthesized biodegradable polymers with side group ofphosphatidylcholine poly(L-lactide) (PLLA) phospholipid polymers (PLLA-PC-PLLA) by L-lactide ring-opening polymerization byL-α-Glycerophosphorylcholine (PC). We have demonstrated a newmethodology of preparing the polymers, and the yield of the polymers was highup to 80%.From the degradable research in vitro of the PLLA-PC-PLLA, we knowthat the speed of PC degradation from PLLA-PC-PLLA was influenced by theratio of LLA/PC of the polymers. And the higher the ratio of PC/LLA of thepolymers is, the quicker the degradation of PC is.In this work, we studied the hydrophilicity, cell compatible and theadhesion of blood platelet of the PLLA-PC-PLLA. It was found that theintrduction of polar phosphatidylcholine to LLA chains had largely changed thehydrophilicity of the synthesized polymers. And from the research ofendothelioid cell (ECV304) compatibility and adhesion of blood platelet, wefound that the cells adhesion of ECV304 on the films of PLLA-PC-PLLA lagedcomparing to PLLA, but then could proliferate and cover the films in total,PLLA-PC-PLLA, the same as PLLA are not cytotoxicity and ECV304 canattach and proliferate on them, and PLLA-PC-PLLA can reduce the adhesion ofblood platelet.In order to obtain biodegradable phospholipid polymers with mechanicalperformance, we used HDI to enlarge the molecular weight of PLLA-PC-PLLA.The result shows, the copolymer we made with the molecular weight was twicehigher than that before chain expanding.