[Study on the temporal change of properties of genipin crosslinked gelatin]

Investigated the changes of crosslinking index, swelling ratio, degradation rate and cytotoxicity of genipin crosslinked gelatin accompany with crosslinking time. 1% genipin crosslinked gelatin were divided into 7 groups by crosslinking time: 10 min group, 30 min group, 1 h group, 2 h group, 12 h group, 24 h group, 72 h group. The results proved that genipin could crosslink gelatin effectively. Accompany with increasing of crosslinking time, crosslinking index increased, and swelling ratio, degradation rate decreased. In 10 min group, crosslinking index was low(26.7%), swelling ratio was high, (265%), completely degraded within 1 week. This indicated that biomaterials of 10 min group was instable and degraded easily. Compared with 10 min group, biomaterials of 30 min group changed significantly with crosslinking index(45.7%), swelling ratio (206%) and degration rate (completely degraded between 4 weeks and 8 weeks). This indicated that genipin could change the properties of gelatin within 30 min. Biomaterials after 30 min, crosslinking index increased, and swelling ratio, degradation rate decreased gradually accompanied with increasing of crosslinking time. Biomaterials of 72 h, crosslinking index was 73.1%, swelling ratio was 152%, and degradated 18.9% after 12 weeks. RGR (relative cell growth rate) of every group measured by MTT assay changed between 87.9% and 105.4%, indicated that the cytotoxicity of genipin crosslinked gelatin was very low.