Abstract
The objective of this research was to discuss the biodegradable thermo-sensitive hydrogel, such as methoxy poly(ethylene glycol)-poly(lactic-co-glycolic acid), mPEG550-PLGA1405, applies to bone tissue regeneration. Several diblock copolymers were synthesized undergoing ring-opening polymerization process. After biocompatibility test, we chose mPEG-PLGA, mPEG-PVLA ( methoxy poly(ethylene glycol)-poly(lactic acid-co-valerolactone) and mPEG-PCLA ( methoxy poly(ethylene glycol)-poly(lactic acid-co- caprolactone) to utilize in rabbit bone defect model. Four weeks later, the result of bone defect regeneration revealed the mPEG-PLGA implant experiments were superiorly than mPEG-PVLA implant experiments. Moreover, mPEG-PLGA were blending with hydroxyapatite (HAp), β-tricalcium phosphate (TCP) to form into a implant composite for rabbit non-union critical-size model. X-ray evaluated bone formation every four weeks postoperatively. The rabbits were sacrificed 12 weeks postoperatively then their femur bones were harvested for micro-computed tomography(μCT), bone mineral density (BMD) and histology study. The results validated the usage mPEG-PLGA/HAp/TCP(7:3) as bone graft substitute. We chose mPEG-PCLA with collagen type II or TGFβ-3 for rabbit cartilage defect model. After eight weeks implant, the rabbits were sacrificed and evaluated by histology. The results validated mPEG-PCLA/collagen type II/ TGF-β3 composites can enhance cartilage repair. Summarily, the biodegradable thermo-sensitive mPEG-poly ester copolymer composites were suitable for bone/cartilage tissue regeneration.