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, 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. Due to 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 detailed. Therefore, the effect of N-methylpyrrole monomer concentration, scan rate, Chi concentration, GOD concentration and GAL concentration on biosensor response was 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; Imax and KM values were calculated using Lineweaver-Burk plot. After 20 successive uses of same enzyme electrode in 5 mM glucose solution, it kept still its 91.3 % of initial activity.

GOD was immobilized onto polypyrrole (PPy) or poly(o-anisidine) (POA) coated Pt electrode to construct glucose sensitive biosensor. Because polymer film properties and enzyme activity affect the current response, PPy and POA synthesis conditions and also enzyme immobilization parameters were optimized in detail. The optimal monomer concentrations were determined as 25 and 50 mM for PPy and POA, respectively, whereas scan rate was 50 mV/s for both polymer films. In case of immobilization procedure, the optimal Chitosan (Chi), glucose oxidase (GOD) and glutaraldehyde (GAL) concentrations were determined as 0.5%, 2 mg/ml and 0.05% for PPy and 0.5%, 4 mg/ml and 0.075% for POA, respectively. Zinc oxide nanoparticles (ZnONP) were co-immobilized with GOD enzyme and it was revealed that ZnONP modification enhanced the efficiencies of both electrodes in terms of current responses and stabilities. Nyquist diagrams showed that enzyme electrodes were sensitive to glucose molecule and ZnONP modification improved the sensor efficiency.