Immobilization of uricase within polystyrene using polymaleimidostyrene as a stabilizer and its application to uric acid sensor.

A novel amperometric uric acid (UA) sensor has been developed by coating the surface of a gold electrode with a polystyrene (PS) membrane formed by 30 microL of a 30 mg mL(-1) PS chloroform solution combined with 30 microL of a 5 mg mL(-1) polymaleimidostyrene (PMS) solution as a dispersant for enzyme, uricase; this membrane has been successfully employed as an immobilization support for uricase. In the PS membrane, PMS forms micelle-like structures containing uricase in an active state. This immobilized uricase membrane permits the permeation of oxygen, which is consumed by the uricase reaction. A good linear relationship is obtained over the concentration range of 5-105 microM. The concentration of uric acid was determined at a negative potential based on the decrease in the reduction current of oxygen and the interference of l-ascorbic acid can be completely eliminated.