Preparation Of Recombinant Human Collagen Thermosensitive Hydrogel And Properties Study

Hydrogels are there-dimensional polymer network in which the voids are filled with water,and have been widely used in many fields.The high water content,good viscoelasticity and plasticity of the hydrogels make it widely studied in biomedical fields.The choice of hydrogel material directly determines whether it can be used as an ideal biomedical material.In this paper,the influence of the amount of P-GP and NaHCO3 in chitosan thermosensitive hydrogels on the gelation time and morphology was studied.Then,RHC was grafted to chitosan and by adjusting the content of the EDC/NHS grafted system and the grafting time,the optimal condition for grafting has been studied.Lastly,the optimal strategy for RHC/chitosan thermosensitive hydrogel were obtained by changing the ratio of RHC and chitosan with the optimal conditions of crosslinking agent and grafting.The physical and chemical properties and biocompatibility of the system were determined by SEM,mechanical test,cytotoxicity and embedding experiments.(1)Add NaHCO3 to the system as a gelling agent.The results showed that both ?-GP and NaHCO3 could improve the gelation rate of hydrogel,increase the mechanical strength of hydrogel with a synergistic effect.Addition of NaHCO3 could effectively reduce the amount of?-GP and improve the potential cytotoxicity of high-concentration ?-GP.With the increase in amount of NaHCO3,Cytotoxicity experiments showed that NaHCO3 had no effect on cell viability.Finally,the best dosage of 200?l/ml,50%?-GP/0.6M NaHCO3 was obtained.(2)RHC and chitosan were grafted by EDC/NHS with the formation of amide bond.The results indicated that RHC and chitosan were successfully grafted.The amount of EDC/NHS had little effects on the gelation time,but the RHC dissolution occurred when the cross-linking time was too short.The best elastic modulus of hydrogel was obtained with the 16mM EDC,80mM NHS and grafted for 4h.(3)By changing the ratio of RHC and chitosan,the gel preparation scheme was finally determined.With the increase of RHC,the amount of mesh structure and pore size of gel increased,cell proliferation was also enhanced.However,chitosan/RHC at ratio of 3:1 showed the best mechanical strength.Based on all these results,chitosan/RHC at the ratio of 3:1 was the best choice for hydrogel preparation.