Electrochemical biosensor based on glucose oxidase encapsulated within enzymatically synthesized poly(1,10-phenanthroline-5,6-dione)

• 1,10-phenanthroline-5,6-dione was chemically polymerized by H2O2 produced in glucose oxidase catalyzed reaction.
• The poly(1,10-phenanthroline-5,6-dione) and glucose oxidase layered structure based biosensor was designed and characterized.
• The poly(1,10-phenanthroline-5,6-dione) layer formed over glucose oxidase based layer showed great electron transfer properties.

This study is focused on the investigation of electrocatalytic effect of glucose oxidase (GOx) immobilized on the graphite rod (GR) electrode. The enzyme modified electrode was prepared by encapsulation of immobilized GOx within enzymatically formed poly(1,10-phenanthroline-5,6-dione) (pPD) film. The electrochemical responses of such enzymatic electrode (pPD/GOx/GR) vs. different glucose concentrations were examined chronoamperometrically in acetate-phosphate buffer solution (A-PBS), pH 6.0, under aerobic or anaerobic conditions. Amperometric signals of the pPD/GOx/GR electrode exhibited well-defined hyperbolic dependence upon glucose concentration. Amperometric signals at 100 mM of glucose were 41.17 and 32.27 μA under aerobic and anaerobic conditions, respectively. Amperometric signals of the pPD/GOx/GR electrode decreased by 6% within seven days. The pPD/GOx/GR electrode showed excellent selectivity in the presence of dopamine and uric acid. Furthermore it had a good reproducibility and repeatability with standard deviation of 9.4% and 8.0%, respectively.

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