TAILORING THE MACROPOROSITY AND PERFORMANCE OF SOL-GEL DERIVED CARBONCOMPOSITE GLUCOSE SENSORS

Control of the preparation conditions is used to enhance the performan ce of sol-gel derived carbon composite enzyme electrodes. In particula r, changes in the water content during the acid-catalyzed hydrolysis s trongly affect the macroporosity of the resulting biogel network. Henc e, while for the low-water process the response is controlled by the e nzyme kinetics, high-water preparations lead to mass-transport restric tions. Such diffusional limitations within the electrode interior resu lt in an extended linear dynamic range (without the need for external membranes). Scanning electron microscopy provides images of biogel mic rostructures, accrued from the use of different water contents. The ce ramic-carbon biosensors offer improved retention of artificial electro n accepters compared to conventional carbon composite bioelectrodes. T he silica-containing surface also displays an intrinsic electrocatalyt ic hydrogen peroxide response, and hence offers a low-potential monito ring of the glucose substrate. (C) 1997 Elsevier Science S.A.