Bienzymatic Glucose Biosensor Based on Poly(vinyl alcohol)/Titanium Dioxide Hybrid Materials and Carbon Nanotubes-Nanocopper-Modified Glassy Carbon Electrode

A highly-sensitive biocomposite bi-enzyme biosensor was fabricated by entrapping glucose oxidase (GOx) and horseradish peroxidase (HRP) in poly(vinyl alcohol)/titanium dioxide PVA/TiO2 hybrid materials immobilized on multi-walled carbon nanotubes and nanocopper modified glassy carbon electrode. The biosensor was examined by cyclic voltammetry and differential pulse voltammetry in the phosphate butter solution. The hybrid material retained the native biocatalytic activity of the entrapped GOD and HRP. In addition, the synergistic effects of carbon nanotubes and copper nanoparticles enhanced the catalytic performance of GOx and promoted electronic transfer. The biosensor exhibited good linearity in the quantitative analysis of glucose within the concentration range from 6.2x10(-8) mol/L to 1.0x10(-6) mol/L (linear regression coefficient=0.998) and had a limit of detection of 1.0x10(-9) mol/L (3 sigma). The apparent Michaelis-Menten constant K-m was 0.037 mu M. Analytical performance was characterized by high sensitivity, good selectivity, reproducibility, and stability.