Electrochemical biosensors based on polymer films immobilized by gamma irradiation

Water-soluble polymers have been immobilized on graphite electrodes and carbon fiber ultramicroelectrodes through gamma irradiation. Gamma rays generate radicals in polymer coatings leading to polymerization and/or cross-linking of the film, resulting in insolubilization of the coating. Polymers which form complexes with species of interest (e.g. neurotransmitters, charged metal complexes) have thus been immobilized. These coatings also serve as barriers toward interferents present in solution. These modified electrodes display enhanced stability during the determination of analytes whose oxidation products form insulating films on electrodes (e.g. phenols and methoxyphenols). Because the films are quite hydrophilic, they make excellent entrapment matrices for radiation-resistant enzymes. Prototype biosensors for adrenergic neurotransmitters and for glucose have been constructed using the above methodology, and present work is focused on extending applications to the development of new biosensors