The Cytocompatible Surface Design On Poly (DL-lactide) Tissue Engineering Scaffold

Three kinds of cytocompatible surfaces on poly (DL-lactide) (PDL-LA) tissue engineering matrix were designed and studied in this dissertation, to promote the cytocompatibility of the PDL-LA material. The cytocompatibility test was then performed on modified PDL-LA tissue engineering matrix using chondrocyte and osteoblast.The Study of in-situ Construction of Cytocompatible Surface on PDL-LA Matrix via Amphiphile-amino acid (RGD) Hybrid Self-segregation-The amphiphilic diblock copolymer, poly(DL-lactide)-poly(ethylene oxide) (PLA-PEO) copolymer, containing hydrophobic PLA block and hydrophilic PEO block was synthesized via coupling method in this dissertation. Cell-adhesion-promoting amino acids and integrin receptor peptide RGD were then immobilized at the end of PEO chain of PLA-PEO copolymer via hydroxyl group activation technique. The solvent blending and casting method was then used to obtain the amphiphile modified PDL-LA membranes. The results of attenuated total reflectance-Fourier transform infrared (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and contact angle measurement showed that the amphiphilic copolymer could self-segregate on the hydrophobic PDL-LA surface. Based on the 'self-migrating and surface-segregation' behavior, The amphiphile segregation surface was therefore constructed on hydrophobic PDL-LA matrix, which containing the structure of PEO spacer combining cell adhesion ligands to mimic the extracellular matrix (ECM).The chondrocyte and osteoblast cytocompatibility test on amphiphilic copolymer-amino acid (RGD) hybrid modified PDL-LA membranes showed that: the cell attachment, growth and activity were promoted on PDL-LA membranes modified by amphiphilic copolymer with alkaline amino acids (arginine and lysine) and RGD end. The result also showed the effect of PEO chain length of amphiphilic copolymer on cell attachment and growth. It showed the best chondrocyte attachment and growth promotion result about the PEO chain with Mn=2000 in this dissertation.Combining the surface self-segregation behavior of amphiphile and salt-leaching technique, the ECM-like surface, with PEO spacer combining amino acid (RGD), wassuccessfully constructed in-situ on PDL-LA 3D tissue engineering scaffold. The result of water-binding ability test including water-retention ability, especially water-adsorption ability, showed great enhancement of hydrophilicity of the modified PDL-LA scaffold, which would favor for the 3D cell culture. The self-segregation behavior of amphiphilic copolymer on PDL-LA scaffold was investigated via fluorescence-labeling technique. The modified scaffold with hydrophilic surface will not only favor the penetration of cell suspension and culture medium, but also provide the microenvironment for the growth of cells with the PEO spacer combining amino acid (RGD) structure.According the above result, the cytocompatibility test was also performed on PDL-LA 3D scaffold modified by amphiphilic copolymer with alkaline amino acid end. The total protein content and cell activity test results showed high proliferation ability and cell activity of the chondrocyte in modified PDL-LA scaffold. It also showed good cell affinity to the modified PDL-LA scaffold investigated by scanning electronic microscopy (SEM) and confocal laser scanning microscopy (CLSM), comparing with the unmodified PDL-LA scaffold. The total protein content, total DNA content and cell activity test results showed high proliferation ability and cell activity of the osteoblast in modified PDL-LA scaffold. It also showed good cell affinity to the modified PDL-LA scaffold investigated by SEM test. The above results verified the good cytocompatibility of the amphiphile-amino acid hybrid modified PDL-LA scaffold. But the result showed that the osteoblast differentiation was not promoted significantly in the amphiphilic-amino acid modified PDL-LA scaffold.The Study of Cytocompatible Surface Construction on PDL-LA Matrix via Biomacromolecules Entrapment-Different polysaccharides (alginate and chitosan) were com...