NEEDLE-TYPE GLUCOSE BIOSENSORS BASED ON A PYROLYZED COBALT-TETRAMETHOXY-PHENYLPORPHYRIN CATALYTIC ELECTRODE

Amperometric needle-type glucose biosensors employing nonplatinum cata lytic electrodes made from pyrolytic electrode of pyrolyzed cobalt-tet ramethoxy-phenylporphyrin (CoTMPP) are described. A technique for prep aration of the working electrode with catalyst and adsorbed enzyme (en zyme electrode) from a pressed matrix (tablet) is presented. This tech nique allows manufacturing numerous sensors from the same pressed tabl et, all of which demonstrate a good reproducibility of their parameter s (sensitivity, linear range, lifetime). Different glucose diffusion ( external) membranes have been studied in order to extend the linear ra nge of the biosensor response. Linearity of the sensor response to glu cose concentrations up to 35 mM is reported when a cellulose paper mem brane, impregnated with cellulose acetate, is used pressed into the ne edle sensor body. Sensors demonstrated a shelf lifetime of 30 days (wi th constant parameters of the signal output) and can be used for conti nuous glucose monitoring in vitro for at least 5 days.