Thermoresponsive poly (N-vinylcaprolactam)-g-galactosylated chitosan hydrogel: synthesis, characterization, and controlled release properties

A dual (thermo- and pH-) responsive hybrid copolymer, poly(N-vinylcaprolactam) grafted galactosylated chitosan (PNVCL-g-GC) was synthesized by EDC/NHS crosslinking. PNVCL-g-GC exhibited a temperature-dependent phase change (LCST) at 32 °C in aqueous solutions. PNVCL-g-GC hydrogel scaffold was fabricated by freeze-drying, and evaluated as a delivery vehicle dependent on environmental pH and temperature. PNVCL-g-GC was characterized using ATR-FTIR, 1H-NMR, DSC, TGA, rheometry, and SEM. The swelling degree increased by the decrease both in temperature and pH. A faster BSA release was observed at 40 °C and at pH 7.2 from the cytocompatible and hemocompatible copolymer.