Needle-type glucose biosensors based on a pyrolyzed cobalt-tetramethoxy-phenylporphyrin catalytic electrode

Amperometric needle-type glucose biosensors employing nonplatinum catalytic electrodes made from pyrolytic electrode of pyrolyzed cobalt-tetramethoxy-phenylporphyrin (CoTMPP) are described. A technique for preparation of the working electrode with catalyst and adsorbed enzyme (enzyme electrode) from a pressed matrix (tablet) is presented. This technique allows manufacturing numerous sensors from the same pressed tablet, all of which demonstrate a good reproducibility of their parameters (sensitivity, linear range, lifetime). Different glucose diffusion (external) membranes have been studied in order to extend the linear range of the biosensor response. Linearity of the sensor response to glucose concentrations up to 35 mM is reported when a cellulose paper membrane, impregnated with cellulose acetate, is used pressed into the needle sensor body. Sensors demonstrated a shelf lifetime of 30 days (with constant parameters of the signal output) and can be used for continuous glucose monitoring in vitro for at least 5 days.