Chemoenzymatic Synthesis and Characterization of Poly(α-methyl galactoside 6-acrylate) Hydrogels

Novel sugar-based hydrogels were synthesized from an enzymatically prepared monomer, α-methyl galactoside 6-acrylate, in the presence of N,N′-methylenebis(acrylamide) (BIS) as the cross-linker. The swelling ratio and elastic modulus of this hydrogel were comparable to those of polyacrylamide hydrogels. The neutral (uncharged) sugar-based gels swelled as much as 100-fold in deionized water at a cross-linker concentration of 0.5 mol %. The incorporation of ionic groups (i.e., acrylic acid moieties) into the network resulted in a dramatic increase in the swelling ratio; however, the swelling fell to the level of the corresponding neutral gel in electrolytic solutions (NaCl or CuCl₂ solution with concentration > 10^–3 M). Conversely, no salt effect was observed for the neutral gels. This poly(a-methyl galactoside 6-acrylate) hydrogel has potential applications as a water-absorbent and as a biocompatible material.