Temperature/pH dual sensitive Hericium erinaceus residue carboxymethyl chitin/poly (N-isopropyl acrylamide) sequential IPN hydrogels

In this study, a novel temperature/pH dual responsive hydrogel, based on Hericium erinaceus residue carboxymethyl chitin (HCMC) and poly (N-isopropylacrylamide) (PNIPAm), was synthesized by sequential IPN technique. Series of IPN hydrogels were obtained by varying initial N-isopropylacrylamide (NIPAm) concentrations. The structure, morphology, thermal property, transparency, mechanical property, swelling kinetics, temperature/pH responses and 5-Fu release behavior of the prepared hydrogels were systematically investigated. The structure analysis results showed that the IPN hydrogels were successfully synthesized. The prepared hydrogels showed more compact network structure and enhanced mechanical property as NIPAm concentration increased, but reduced transparency, swelling degree and 5-Fu release ratio. More importantly, HCMC and PNIPAm ensured the pH and temperature responses, respectively. 5-Fu could be gradually released from the prepared hydrogels, which followed Fickian diffusion model. Therefore, the prepared hydrogels may be served as promising materials for drug delivery systems.