Gelation Process and Physicochemical Properties of Thai Silk Fibroin Hydrogels Induced by Various Anionic Surfactants for Controlled Release of Curcumin

Abstract

AbstractHydrogels based on Thai silk fibroin (SF) were prepared by the induction of various anionic surfactants including sodium octyl sulfate (SOS), sodium dodecyl sulfate (SDS), and sodium tetradecyl sulfate (STS), which have a similar chemical structure but different alkyl chain lengths and charges. The effects of anionic surfactant types and their concentrations on the gelation mechanism and time of SF were systematically investigated. We found that SDS and STS that have long alkyl chain lengths and high negative charges could accelerate the gelation of SF to occur within 14–42 min in a concentration‐dependent manner. SOS that has a short alkyl chain length and low negative charge slowly induced SF to gel at around 113–144 h. The mechanisms of SF gelation induced by these three anionic surfactants were supposed to be combination of hydrophobic and electrostatic interactions, as well as the self‐transition of beta sheets. The SF + STS hydrogels were further employed to encapsulate curcumin for the controlled release application. The SF + 0.09% wt. STS hydrogel encapsulating curcumin showed a slow rate of degradation while sustained the release of curcumin. This hydrogel can be applied as a minimal invasive injectable hydrogel or as a hydrogel for topical treatment of diseases.