Characterization of Electrochemically Synthesized PANI/GOD/MWNTs Composite

Abstract

x ABSTRACT Carbon Nanotubes (CNTs) are 1D structure, consisting of cylindrical graphite sheets with nanometer diameter and large aspect ratio. They have attracted enormous interest over past number of years due to their excellent electrical, mechanical and chemical properties. The combination of biological molecules and CNTs is of great importance in the process of developing new nano-scale devices for future biological, medical and electronic applications. Glucose oxidase (GOD) is a flavin enzyme used commercially on massive scale to monitor blood glucose level in diabetics. The GOD enzyme can be attached to MWNTs and can be reversibly oxidized without complete loss of enzymatic activity. The present thesis work is concentrated on the functionalization of MWNTs (f- MWNTs), attachment of GOD on f-MWNTs, GOD activity in GOD-MWNTs composites at different time intervals and finally fabrication of enzyme electrode. GOD is attached with acylated MWNTs (a-MWNTs). The functionalization of MWNTs and the attachment of enzyme to MWNTs were carried out by chemical route and it was further characterized by FT-IR and FE-SEM techniques. Enzyme activity is an important aspect for the development of biosensor. During this work, the activity measurements were carried out with UV-Visible spectrophotometer using SIGMA standard procedure. The results conclude that GOD retained its activity even after immobilization on f-MWNTs. Every week (maximum up to 8 weeks), the experiments related to the measurement of enzyme activity was repeated and GOD in GOD-MWNTs composite was again found active. Conducting polymers are highly flexible in their chemical structure and redox characteristics. The composite of polyaniline and MWNTs was prepared by electrochemical technique on ITO coated glass plates. These composites were characterized by FT-IR and Cyclic Voltammetry techniques. The peak shift in the cyclic voltammogram of these composites, revealed the functionalization of MWNTs, attachment of GOD to f-MWNTs and formation of PANI/ GOD-a-MWNTs composite.