MONITORING AND SENSING OF GLUCOSE MOLECULE BY MICROPILLAR COATED ELECTROCHEMICAL BIOSENSOR VIA CuO/[Fe(CN)6] 3- AND ITS APPLICATIONS

Abstract

This thesis explores the advancements in monitoring and sensing glucose molecules using micropillar-coated electrochemical biosensors. Glucose sensing through electroanalysis has emerged as one of the most widespread and commercially successful applications in the field. By leveraging the principles of amperometry, which involves the measurement of electric current, electrochemical glucose sensors provide accurate assessments of glucose concentration in samples. This process entails the application of a voltage that initiates the oxidation of glucose, with the resulting current being measured at the electrode. A crucial aspect of designing an effective glucose sensor lies in establishing a linear relationship between glucose concentration and the measured current, enabling precise and calibrated measurements. In the typical configuration of a glucose sensor, the oxidation of glucose does not occur directly at the working electrode where the current is measured. Instead, a chemical oxidant is employed to facilitate the reaction, which is further accelerated by the presence of a biological enzyme, such as glucose oxidase. This combination of chemical and biological components ensures the sensor's specificity to glucose and its independence from the concentration of other oxidizable species that may be present in the analyte solution. However, reliance on atmospheric oxygen concentration poses challenges. The reduced form of the oxidant, after reacting with glucose, can be re-oxidized directly at the electrode. Although oxygen is the natural oxidant, its slow kinetics and susceptibility to variations in atmospheric oxygen levels can introduce inaccuracies and complications in glucose measurements. To overcome these challenges, researchers have explored alternative approaches and devised strategies to enhance the performance of glucose sensors. One such strategy involves the utilization of mediators, which act as electron shuttles between the electrode and the enzyme. These mediators bypass the dependence on oxygen for the re-oxidation process, resulting in faster and more efficient electron transfer. Consequently, improved sensor response times and reduced susceptibility to variations in atmospheric oxygen levels are achieved. Furthermore, the integration of nanotechnology has played a pivotal role in the development of glucose sensors. Nanomaterials, including carbon nanotubes, graphene, and metal nanoparticles, offer increased sensitivity, stability, and selectivity. These nanomaterials provide a large surface area for enzyme immobilization and exhibit excellent electrical conductivity, facilitating efficient electron transfer between the electrode and the glucose oxidation reaction. Functional group modifications and specific enzymes further enhance the sensor's specificity for glucose.