Graphene Hybrid Nanomaterials for Electrochemical Nonenzymatic Sensing of Glucose and Hydrogen Peroxide

Abstract

The development of biosensors is an excellent example of how a very simple and elegant idea leads to an innovative breakthrough in science and technology, which is currently influencing all areas of our life. In 1962 Clarks and Lyons proposed a glucose oxidase (GOD) based sensor for the determination of blood glucose. After that development of biosensors became one of the important areas of research. These sensors exhibited high sensitivity and selectivity, however, they suffer from several drawbacks such as instability and limited shelf life due to the intrinsic property of enzyme. To address this limitation an alternative approach based on the direct electrooxidation/reduction without the use of enzyme (nonenzymatic) has been tried. The direct electrooxidation of glucose and other biomolecules on different noble metal substrates, transition metals and their metal oxides have been investigated. After the invention of graphene and other carbon nanostructures, several hybrid materials have been employed for the quantification of glucose and various other biomolecules. Disposable sensor electrode has been used for the point of care sensing of biomolecules. In the first part of the thesis, a few important approaches of modifying the screen printed electrodes (SPE) with graphene-metal-metal oxide hybrid nanomaterials and used for the sensing of glucose. The second part describes the development of hydrogen peroxide sensors based on graphene-metal nanocomposites. In the first approach, gold-copper oxide nanoparticles decorated reduced graphene oxide (Au-CuO/rGO) nanocomposite was synthesized and thoroughly characterized by spectroscopic, microscopic and electrochemical methods. The disposable screen printed electrodes were fabricated indigenously. The Au-CuO/rGO nanocomposite was dispersed in DMF and cast on the working electrode and dried (Au-CuO/rGO/SPE). The nanocomposite modified electrode was employed for the detection of glucose.