Design Of The Crosslinking System For Chitosan Or Gelatin And Evaluation Of Their Cytocompatibility

As a glycosaminoglycan and protein, chitosan and gelatin have extensive application foreground in the biomedical field. In order to reduce the toxicity of the normal chemical crosslinkers of chitosan and gelatin, such as glutaraldehyde, firstly chitosan-g-poly (lactic acid) hydrogels were prepared by the graft copolymerization of chitosan with L-lactic acid without any crosslinker. Using IR, XPS and kinetic contact angle analysis, CL hydrogels were characterized. The mechanical properties and cytocompatibility of CL hydrogels were also investigated. The results showed that the crosslinking of chitosan resulted from the hydrophobic association of the side chains of oligo (lactic acid) segments. The mechanical strength of CL hydrogels could be adjusted by the feed ratio of lactic acid to chitosan and the cytocompatibility of the hydrogels were similar with chitosan itself. Secondly, chitosan, gelatin and chitosan-gelatin complex gels were prepared with a natural crosslinker—genipin. The mechanical, swelling properties and cytocompatibility of the gels were investigated using glutaraldehyde as control. It was found that the mechanical performance and cytocompatibilty of the genipin crosslinked gels were improved significantly. So two different nontoxic crosslinking methods for chitosan and gelatin were established. Finally, chitosan, gelatin and chitosan-gelatin complex scaffolds were fabricated through freeze-drying using genipin as crosslinker. The porosity, mechanical performance and morphology of the scaffolds were investigated and the results suggested that the obtained scaffolds have promising potential in tissue engineering.