Biocompatible hydrogels of carboxymethyl hyaluronic acid prepared by radiation-induced crosslinking

Abstract

Carboxymethyl hyaluronic acid (CMHA) hydrogels crosslinked by radiation are ideal candidates for biocompatible materials. We have previously prepared CMHA hydrogels by radiation crosslinking in paste-like state or highly concentrated aqueous solution without the addition of any initiators or crosslinking agents. In this study, CMHAs with degree of substitution (DS) of 0.34–0.74 were synthesized. The crosslinking of CMHA with DS of 0.74 and Mw of 314 kDa by gamma-irradiation at 10%–60% w/w concentration and doses of 20–120 kGy was evaluated. CMHA degraded at 10% and 20% concentration as no gel content was measured for all dose range. For concentrations 40% and 60%, the gel content ranged from 15% to 68%. Crosslinking efficiency was improved compared to our previous study due to increased DS and molecular weight. Swelling in water of CMHA hydrogels ranged from 43 to 2400 g H2O/g dry gel. FTIR results showed that crosslinking was accompanied by changes in the chemical structure. Thermal stability of crosslinked CMHA was found to decrease with increasing dose. CMHA hydrogels prepared at 60 and 120 kGy did not show any cytotoxic effects as evaluated by MTT assay. The range of swelling properties and good biocompatibility can open a wide variety of applications for radiation-processed CMHA hydrogels.