Synthesis Of Modified Plla And Its Application In Tissue Engineering Scaffold

In this thesis, poly(L-lactic-co-citric acid)(PLCA) was prepared by directly melt polycondensation. Multiblock copolymers(PLCA-OHPLLA-PEG) was obtained from the polycondensation reactions between PLCA , PEG and dihydroxylated-PLLA in the presence of dicyclohexyl carbodiimide and N,N-dimethyl aminopyridine as catalysts. The structure and molecular weights of the copolymers were characterized by ~1H-NMR and GPC, and their degradation rates was also studied. By the method of gelation and freeze-drying, tissue engineered scaffolds with different compositions were fabricated from PLCA-OHPLLA-PEG and PLLA. Morphology and mechanical properties of the scaffolds were studied. Morphology of the scaffolds was examined using SEM. Results showed that the prepared scaffolds exhibited highly porous and open-cellular pore structures. The average fiber diameter were about 200-400 nm on the same scale as those of collagen fibers in extracellular matrix. The sustained release of tetrandrine from the scaffolds in vitro was also studied. The dissolution medium was assayed with high-performance liquid chromatography method. It was found that drug release was effectively controlled by the composition of the scaffolds.