Preparation And Property Study Of Chitosan-PEG Hydrogel For Articular Cartilage Repairment

Articular cartilage injury is a severe disease, which has low self-repair capability due to shortage of blood supply. Tissue engineering utilizes principles of biological science and engineering to construct bionic tissue, therefore becoming a new direction for articular cartilage repair. In this work, we prepared articular cartilage repairing hydrogel material using chitosan and polyethylene glycol as matrix, and further studied its equilibrium water content, microscopic morphology, pore size and porosity, mechinical property, in vitro degradation rate and its biocompatibility. Finally, its potential as articular cartilage repairing material was discussed.Hydrogels are widely used in tissue engineering due to their high water content, biodegradability and excellent biocompatibility. In this study, a water-soluble chitosan derivative, acrylated hydroxypropyl chitosan (AHCS) with different substitution degree (SD) of acrylation,1.03%,3.55% and 5.21%, was prepared by chemical modification to chitosan. AHCS and polyethylene glycol diacrylate (PEGDA) were chemically gelated to form cocrosslinked CS-PEG hydrogel. SEM showed it was a multipore scaffold with high connection rate. As SD increased, sol content and swelling ratio (SR) of the hydrogels both decreased and for the same SD, SR was higher in acid or alkaline conditions than in neutral condition. Degradation rate (DR) of chitosan in the hydrogels decreased with increase of SD.The influence of CS/PEG weight ratio on CS-PEG hydrogel properties was studied. Results showed that sol content (SC) and equilibrium water content (EWC) of CS-PEG hydrogel decreased with increase of PEG content. Pore size increased with increase of PEG content, however, porosity decreased. The compressive elastic modulus improved with increase of PEG content. Compressive elastic modulus for CS67PEG33, CS50PEG50 and PEG100 were 30±5kPa,75±10kPa and 140±8kPa, superior to native articular cartilage (500-1 000kPa). CS-PEG hydrogel had biodegradability to a certain extent and the degradation rate dropped with increase of PEG content. Through in vitro cytotoxicity experiment, it was testified that CS50PEG50 was nontoxic to L929 cell line and thus, had good biocompatibility.Results suggested that CS-PEG hydrogel had proper equilibrium water content, highly connected porous structure and its pore size and porosity met the requirements of articular cartilage repairing material. Through adjusting substitution degree of AHCS or weight ratio of CS to PEG, in vitro degradation rate and mechanical strength could be modulated. Besides, CS-PEG hydrogel had good biocompitibility. Taken together, CS-PEG hydrogel is a potential articular cartilage repairing.