Smart pH/magnetic sensitive Hericium erinaceus residue carboxymethyl chitin/Fe3O4 nanocomposite hydrogels with adjustable characteristics

A smart hydrogel with pH/magnetic dual sensitivity was synthesized by in-situ synthesis of Fe 3 O 4 inside carboxymethyl chitin hydrogel matrix prepared from Hericium erinaceus residue. The structure, pH/magnetic sensitivity, swelling and drug release behavior of the prepared hydrogels were investigated. The results showed that Fe 3 O 4 nanoparticles were successfully synthesized and uniformly distributed within the hydrogels. The prepared hydrogels could be attracted by the magnet and exhibited sustained shrinkage behavior at low pH, with the desirable pH/magnetic sensitivity. The formed Fe 3 O 4 could be developed inside the hydrogels by increasing the concentrations of precursor Fe 2+ /Fe 3+ ions, and the magnetic sensitivity of hydrogels was enhanced, while the pH sensitivity and swelling degree were weakened. The Fe 3 O 4 content-dependent behavior of the prepared hydrogels suggested the adjustable properties of hydrogels. The release of 5-Fu in simulated gastric and intestinal fluids followed the Fick diffusion mechanism and showed different release rates, indicating the pH-controlled drug release behavior.