Construction of reagentless glucose biosensor based on ferrocene conjugated polypyrrole

Glucose oxidase (GOx) was covalently immobilized onto an electrochemically prepared novel copolymer of ferrocene branched polypyrrole for the construction of an amperometric glucose biosensor. Ferrocene-pyrrole monomers were prepared by condensation reaction between ferrocene ethanol and 3-(1H-pyrrol-1-yl)propanoic acid and ferrocene-pyrrole, 3-(1H-pyrrol-1-yl)propanoic acid, and pyrrole monomers were electrochemically polymerized on the surface of the electrode. GOx was covalently immobilized onto the co-polymer coated electrode surface by using coupling agents to create amine bonds. The prepared copolymers were utilized as conducting films for amperometric glucose sensing after immobilization of GOx. Amperometric response was measured as a function of concentration of glucose at a fixed potential of +0.38 V vs. Ag/AgCl in a phosphate-buffered saline solution (pH 7.0). Results clearly showed that the ferrocene groups on the co-polymer play the role of electron transfer mediator between the redox center of glucose oxidase (GOx) and the surface of the electrode. Also, the effects of pH and temperature, storage, reusability and interference of the amperometric glucose biosensor were investigated.