AMPEROMETRIC GLUCOSE BIOSENSOR BASED ON A TETRATHIAFULVALENE-MEDIATED EPOXY-GRAPHITE BIOCOMPOSITE

An inexpensive, robust, and easily mechanized amperometric glucose sensor based on a biocomposite material has been constructed. The biocomposite is made of graphite, a nonconductive epoxy resin, tetrathiafulvalene (TTF) as a redox mediator, and glucose oxidase (GOD). The enzyme retains its bioactivity on confinement in the rigid epoxy-graphite matrix; with the oxidation current of the reduced mediator serving as the analytical signal (at 150 mV [vs. Ag/AgCl] in a pH 7.00 buffered solution featuring 0.1 M phosphate and 0.1 M KCl). The resulting biosensor shows a linear response in the 0.1 to 2 mM glucose range and produces a steady-state signal within a few seconds (11 seconds for a 95% response). Simple polishing procedures can be used to regenerate a freshly bioactive transducer surface.