Poly(N-Methylpyrrole)-Chitosan layers for Glucose Oxidase Immobilization for Amperometric Glucose Biosensor Design

Abstract

In this study, Pt electrode was coated by poly(N-methypyrrol) (PNMP) film, then Glucose Oxidase (GOD) was immobilized onto PNMP layer with thin chitosan (Chi) gel, and finally, the electrode was reacted with glutaraldehyde (GAL) to form crosslinking between –NH2 groups of Chi and GOD to prevent enzyme leakage from Chi. GOD-based electrode was used to measure current response depending on glucose concentration by chronoamperometric method. The preparation of electrode conditions have significant effect on current values which were measured and optimized in presence of glucose, polymer synthesis and GOD immobilization conditions. Therefore, the effect of N-methylpyrrole monomer concentration, scan rate, Chi concentration, GOD concentration and GAL concentration on biosensor response were investigated by classical method. In sight of obtained data, optimal monomer concentration and scan rates for PNMP synthesis were determined as 50 mM and 20 mV/s, respectively. Optimal Chi, GOD and GAL concentrations were found as 1,00%, 4 mg/mL and 0.025 %, respectively. SEM images of Pt, PNMP coated Pt and GOD immobilized Pt electrodes were obtained. After 20 successive uses of same enzyme electrode in 5 mM glucose solution, it was still its 91.3 % of initial activity.