Synthesis and evaluation of hyaluronic acid–poly(ethylene oxide) hydrogel via Michael-type addition reaction

Hyaluronic acid-based hydrogel was synthesized by reacting hyaluronic acid with aminopropyl methacrylate and then with poly(ethylene oxide). Gelation was observed within 5.5 h with a rheometer by employing viscous and elastic modulus. While the hydrogel was analyzed by light and electron microscopy for morphological observation, other analysis was performed by Fourier-transformed infrared and electron spectroscopy for chemical analysis. Understanding of a putative reaction scheme was outlined by reference to N-(3-diethylpropyl)-N-ethylcarbodiimide hydrochloride for acrylation of hyaluronic acid and by a Michael-type reaction between methacrylate in aminopropyl methacrylate and thiol arms in PEO end groups.