Electrically Conductive Polymers As Electrode Coatings for Entrapped Enzyme Biosensors

A biosensor has several key components such as sample delivery, sensing material, transducer and data processor. We are focused on the sensing material and transducer, as it is imperative to the operation of the device that they communicate efficiently. In a biosensor incorporating an enzyme which catalyzes a redox reaction of a substrate, a sensing material made of a electrically conductive polymer is adhered to a physical transducer to convert change in oxidation into a physical signal (a current).  The electrically conductive polymer transports the electrons from the redox reaction of the embedded enzyme to the electrode.

For such a biosensor to work reliably, a uniform and reproducible coating of conductive polymer must be laid down upon a base electrode, such as a carbon fiber.  In this work, cyclic voltammetry is used to carry out the electropolymerization of monomers such as aniline and 8-anilino-1-napthalene sulphonic acid (PANSA). Uniformity of coating is assessed as a function of reaction conditions such as pH, catalyst, and monomer concentration. Such a coating process will ultimately be used to entrap substrate-sensing enzymes, thus providing the base platform for a enzyme-mediated single-use disposable biosensor.