Chemoenzymatic synthesis of sugar-containing biocompatible hydrogels: Crosslinked poly(β-methylglucoside acrylate) and poly(β- methylglucoside methacrylate)

Sugar-containing biocompatible hydrogels were synthesized chemoenzymatically by the following two steps: 1. lipase-catalyzed esterification of β-methylglucoside with acrylic acid/methacrylic acid/vinyl acrylate/vinyl methacrylate in solvent as well as solvent-free process for the formation of sugar-containing monomers; and 2. polymerization process by free-radical polymerization with and without a crosslinker, ethylene glycol dimethacrylate (EGDMA). The solvent-free process resulted in an initial reaction rate approximately 1.5-2 times faster than that of the solvent process along with a complete consumption of β-methylglucoside during the alcoholysis. The presence of pendant vinyl groups in β-methylglucoside acrylate (MGAA) and β-methylglucoside methacrylate (MGMAA) was confirmed by ¹H/¹³C NMR analysis, whereas the successful polymerization with the consumption of the vinyl groups was confirmed by Fourier transform infrared spectroscopy and ¹³C NMR spectra. The surfaces of both poly(MGAA) and poly(MGMAA) were analyzed using scanning electron microscopy. The increased contents of EGDMA resulted in a higher tensile strength as well as a reduced swelling ratio of poly(MGAA) and poly(MGMAA). The swelling exponents were within the range of 0.53 and 0.98. In vitro cytotoxicity tests by MTT assay exhibited >90% cell viability in the poly(MGAA) and poly(MGMAA) without EGDMA, whereas a significantly decreased cell viability was observed for those with EGDMA.