Direct coupling of glucose oxidase to platinum and possible use for in vivo glucose determination

Glucose oxidase was attached to platinum-platinum oxide screens via alkylamine silaneglutaraldehyde coupling. The amount of immobilized enzyme was equivalent to 0.0031 μg of soluble glucose oxidase per cm² of screen surface. The platinum-silane-glutaraldehydeenzyme screens were tested potentiometrically in buffered glucose solutions, with respect to a Ag/AgCl reference electrode. The results were expressed as the difference in potential for the enzyme screens placed in buffer containing glucose and placed in plain buffer. This difference in potential was related linearily to the logarithm of the glucose concentration over the range 5-150 mg glucose/100 ml. The source of the potential may be due to the decomposition of hydrogen peroxide produced by the glucose oxidase catalyzed oxidation of glucose. The approach is being studied for possible development of an implantable sensor for continuous in vivo monitoring of glucose levels.