Abstract:
This research aimed to fabricate hydrogels from Thai silk fibroin/gelatin/hyaluronic acid (SFGHA) for the use as scaffolds. The hydrogels at different weight ratios including SF50G50, SF50G25HA25, and SF50HA50 were prepared by freeze-drying technique and crosslinking by immersion in 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) solution in ethanol as a solvent. The results showed that 20 mM of EDC could be successfully used to crosslink SFGHA hydrogels at the crosslinking time of 6 h. The weight loss of all hydrogels after crosslinking was in the range of 4-5%. The contents of N-acetyl-D-glucosamine of hydrogels before and after crosslinking were rather similar. This suggested that most HA molecules could be crosslinked by EDC. The cross-sectional morphology of obtained hydrogels showed that increasing HA content would result in larger pore size of blended hydrogels. The results on ATR-FTIR proved that the chemical structure of hydrogels before and after crosslinking were different, possibly because of two main causes including ethanol used as the solvent in crosslinking process and the reactions of EDC crosslinking. To test water absorption all hydrogels were soaked in phosphate buffer saline (PBS) at 37oC. It was observed that the degrees of water absorption of hydrogels containing 25 and 50% of HA were around 5200% (or 52 fold). The results on degradation of hydrogels showed that protein hydrogels (SF50G50) was degraded in protease XIV solution faster than hydrogels with polysaccharide incorporation. But hydrogel with 50% of HA could be hydrolyzed via ester bond faster than others hydrogels when it was immersed in culture medium. The hydrogels with HA incorporation could support attachments and proliferation of NIH/3T3 mouse embryonic fibroblasts better than other hydrogels, possibly because of high hygroscopic properties of HA. However, the morphology of attached cells were quite round due to highly negative charges of the HA. The results indicated that SFGHA hydrogels possessed suitable properties for further use as scaffolds.