Organic/inorganic films for biosensor application

Abstract

Biosensors are becoming increasingly important as practical tools in pathogen detection and molecular diagnostics. Electrochemical biosensors are of particular interest due to several advantages including low-cost, easy operation, and small size. During the development of efficient biosensors, a crucial part is the choice of material onto which a biomolecule has to be immobilized while providing good electron transfer rate at the electrode as a result of a biochemical reaction. Present work deals with the development of novel nanostructured metal oxides and conducting polymer nanocomposites as promising material matrix for biomolecule immobilization, because of their high surface to volume ratio and efficient electron transport properties. We have synthesized ferrocene-polypyrrole based nanocomposites with excellent mechanical and electronic properties. The optimized nanocomposite films have been used for glucose biosensor. Results indicate the good performance of the electropolymerized copolymer of pyrrole and ferrocenecarboxylate modified pyrrole P(Py-FcPy) on indium-tin-oxide (ITO) coated glass for glucose biosensor. On the other hand an inorganic material structure, ZnO nanorods (ZnONR), has been grown on indium tin oxide (ITO) films on glass. This could easily be upgraded with existing MEMS technology to fabricate miniaturized biosensors. Urease (Urs) enzyme was physically immobilized on nanorods exploiting high isoelectric point of ZnO to fabricate Urs/ZnONR/ITO bioelectrode. Urs/ZnONR/ITO bioelectrode revealed a very high sensitivity of 10 µAdL/mg (1.66 µA/mM) in a urea concentration range of 10-25 mg/dl with enhanced linearity.