Influence of polymerization parameters and entrapment in poly(hydroxyethyl methacrylate) on activity and stability of GOD

The functional stability of biosensors used in vivo seems, most probably, to be limited by enzyme instability. Therefore, investigations have been carried out on enzyme stabilization by immobilization using poly(hydroxyethyl methacrylate) (pHEMA). On one hand, there are several factors connected to polymerization of the monomer hydroxyethyl methacrylate (HEMA) able to influence the activity of enzymes during their entrapment in the polymer. The factors we investigated are: the concentration of the monomer, different temperatures (50-65 degrees C), ultraviolet radiation, and the concentration of radicals generated by different initiator concentrations. Glucose oxidase I(GOD) was used as a model enzyme. It was found that the most important GOD inactivating factors are the monomer itself and temperatures higher than 50 degrees C. On the other hand, despite of these influences a long term stable immobilization of GOD by entrapment in pHEMA could be realized. (C) 1999 Elsevier Science B.V. All rights reserved.