Stabilization of enzyme immobilized in temperature-sensitive hydrogels

β-Galactosidase was immobilized in a crosslinked poly(N-isopropylacrylamide-co-acrylamide) hydrogel which exhibits an LCST(lower critical solution temperature) behavior. The hydrogel collapses above the LCST, and expands below the LCST. The temperature-dependent phase transition was around 37 °C. The stability of immobilized enzyme was investigated at different temperatures which allow different degrees of collapse in the hydrogel matrix. It was hypothesized that the immobilzed enzyme is more stable in the collapsed matrix due to the physical restraint imposed on the enzyme entrapped.