Glucose biosensors based on oxygen electrode with sandwich-type membranes

A glucose biosensor based on an amperometric oxygen electrode has been developed. Polycarbonate and Silastic membranes were assembled (glued together) to form a multilayer sandwich glucose diffusion barrier. The effects of the glue layer composition and thickness of the Silastic membrane on sensor response parameters have been investigated in order to optimize the sensor. The parameters measured were the sensitivity, the concentration range of the linear dependence of the sensor response to glucose, and the long-term operation time. The sensors with the sandwich-type glucose diffusion membrane (Silastic membrane prepared from 20% Silastic suspension, glue layer prepared from polyurethane, 0.5 w/v % in THF solution and standard polycarbonate membrane) demonstrated linearity of response up to 520 mg/dl glucose at 25°C and up to 400 mg/dl at 37°C. These sensor showed good reproducibility of response without significant interference effects (from 1 to 5% of the background current value). The long-term continuous operational time of the sensors was over 40 days at 37°C, and over 60 days at 25°C.