Nano-HA/PLGA Scaffold For Cartilage Tissue Engineering: Development And Experimental Study

In this thesis, a novel porous composite scaffold of nano-HA/poly (lactic-co-glycolic) (PLGA) was fabricated by solvent casting/particulate leaching method. The surface appearance of the scaffold was evaluated by FE-SEM, infrared ray (IR) and X-ray diffraction spectrograms (XRD). The porosity of the scaffold was investigated by pycnometers. Results revealed that nano-HA/PLGA composite scaffolds have good surface morphology, and the nano-HA particles were homogenously dispersed in the PLGA matrix. The porosity of the scaffold is up to 90%.Six groups of nano-HA/PLGA composite scaffolds with different contents of nano-HA and PLGA were fabricated. Phosphate buffer succus (PBS) system has been used to investigate the degradation process of nano-HA/PLGA composite. The samples after degradation were evaluated by FE-SEM, IR and XRD. The pH of the PBS, the water absorption and the weight loss were also been tested. Results indicated that the degradation of PLGA causes the decrease of pH, which could accelerate the degradation of the composites. The scaffold will degrade at a controlled rate through the incorporation of nano-HA into PLGA. All types of scaffolds were seeded in the subcutaneous of back of rabbits. The scaffolds were harvested after in vivo incubation of 3 and 6 weeks and evaluated histologically by hematoxylin and eosin staining.Chondrocytes were isolated from the knee articular joints of a rabbit, and then seeded in the scaffolds. The cell-loaded scaffolds were cultured in vitro for 5 days before implantation. Full-thickness articular cartilage defects were created in rabbits, and filled with and without the cell-loaded nano-HA/PLGA scaffolds. The implants were harvested after in vivo incubation of 2 and 5 weeks. Cartilaginous tissues were observed at defects repaired with the cell-loaded scaffolds, while only fibrous tissues were found for the control groups. The repaired tissues were evaluated histologically by hematoxylin and eosin staining. Results revealed that nano-HA/PLGA composite scaffolds facilitated adheration of cells in vitro, and the nano-HA particles could prevented the scaffolds from collapsing and promoted the formation of cartilaginous tissue in vivo.