Glucose-sensitive hydrogels were prepared by the copolymerization of diethylaminoethyl methacrylate (DEAEM), poly(ethylene glycol) monomethacrylate (PEGMA) and functionalized glucose oxidase (GOD) and catalase in solution. Tetra(ethylene glycol) dimethacrylate (TEGDMA) was used as the crosslinking agent. The equilibrium and dynamic swelling properties were studied to investigate the pH-sensitive swelling behavior of the gels. The effects of crosslinking ratio and enzyme content on the swelling properties were studied. The hydrogels demonstrated critical swelling behavior as the pH approached 7.0. The mesh sizes and the diffusion coefficients were determined. Dynamic swelling studies were performed and the results were analyzed using a first-order model to calculate the time constants of swelling and synthesis. Pulsatile swelling studies revealed the reversible nature of the swelling/deswelling process. (C) 2000 Elsevier Science Ltd. All rights reserved.