Carbon-polymer biocomposites for amperometric sensing

New electrochemical sensing biocomposite materials are reported. These materials are based on polymer technology and are prepared mixing graphite powder, a non-conducting polymer resin and a lyophilized enzyme. The resulting biosensing material is inexpensive, robust, polishable and easy to machine. A survey of potentially suitable polymeric matrices was carried out. Epoxy, silicone, methacrylate and polyester polymers have been used to prepare rigid conducting composite materials of the graphite-polymer type. For each material, an optimal graphite content was determined. Amperometric transducers built with these materials were characterized electrochemically using cyclic voltammetry and linear-sweep voltammetry. Their linear response to hydrogen peroxide was evaluated. The applicability of these conducting polymer-graphite composites has been extended to the construction of conventional glucose biosensors. In these devices the conducting composite is bulk-modified with the addition of glucose oxidase. The amperometric detection of hydrogen peroxide serves as the analytical signal. Following the same construction method, it is also possible to obtain other biosensing systems. New biocomposites have been prepared, using a different enzyme in each case, i.e. acetylcholinesterase and peroxidase.