Immobilization of glucose oxidase enzyme onto organic-inorganic sol-gels matrix on carbon paste electrode biosensor

Abstract

A hybrid sol-gel carbon nanotubes composite has been developed and used for surface covalent bonding of enzyme for biosensing application. The biosensor was developed by covalent immobilization of glucose oxidase enzyme on sol gel modified electrode with ferrocene via carbodiimide reaction. The presence of amine groups provided by APTMOS in sol gel controlled the covalent bonding sites for enzyme. The experiment conditions such as amount of enzyme and pH in working buffer was studied by using Response Surface Methodology (RSM) through Central Composite Design (CCD) of Design Expert software. The biosensor showed maximum current response at 20 U/mL of immobilized glucose oxidase at the optimum pH value of working buffer of pH 7. The calibration curve of GOx biosensor was linear in the range of 0.1 mM to 3 mM of glucose concentration with a linear equation and correlation coefficient of 0.9873. The performance of GOx biosensor was evaluated based on selectivity toward the interferences and stability, the GOx biosensor exhibited high selectivity behavior and good stability.