The potential use of thermosensitive chitosan/silk sericin hydrogels loaded with longan seed extract for bone tissue engineering.

In this study, hydrogels that were thermosensitive at body temperature were developed using chitosan (CS)/silk sericin (SS)/β-glycerophosphate (β-GP) loaded with longan seed extract (LE) for use in bone tissue engineering. These hydrogels were transformed into a gel at 37 °C within 10 min via interactions between CS and β-GP. The incorporation of SS resulted in a shorter gelation time of 5-7 min. The morphological structure of the thermosensitive CS/β-GP hydrogels exhibited an irregular pore structure, whereas the morphological structure of the thermosensitive CS/SS/β-GP hydrogels became more slender and porous. The incorporation of SS affected the network structure of the CS hydrogels, which degraded more rapidly. Moreover, the cumulative amounts of both gallic acid (GA) and ellagic acid (EA) released from the hydrogels loaded with LE increased with an increase in the SS content. Finally, these thermosensitive hydrogels were non-toxic to both a mouse fibroblast cell line (NCTC clone 929) and a mouse osteoblast cell line (MC3T3-E1) and promoted the attachment of MC3T3-E1 cells to the surface of the hydrogels. Therefore, these thermosensitive hydrogels might be a promising candidate for bone tissue engineering.