Reagentless biosensor based on glucose oxidase wired by the mediator freely diffusing in enzyme containing membrane

Area of Science:

• Biotechnology
• Electrochemistry
• Biosensor technology

Background:

• Biosensors rely on enzyme and mediator immobilization for accurate analyte detection.
• Traditional methods often require complex covalent linking, limiting flexibility and potentially affecting enzyme activity.

Purpose of the Study:

• To develop a novel protocol for wiring glucose oxidase with an immobilized mediator in a biosensor membrane.
• To discover and characterize a new mediator for glucose oxidase-based biosensors.
• To evaluate the analytical performance and stability of the developed biosensor.

Main Methods:

• Formation of enzyme-containing membranes using water-organic mixtures.
• Identification and characterization of unsubstituted phenothiazine as a novel mediator.
• Electrochemical analysis using cyclic voltammetry to assess enzyme electrode performance.
• Evaluation of biosensor operational stability and analytical parameters.

Main Results:

• Successful immobilization of glucose oxidase with an immobilized mediator through a novel protocol involving water-organic mixtures.
• Discovery of unsubstituted phenothiazine as an effective mediator for glucose oxidase.
• Mediator diffusion coefficient in the membrane is independent of enzyme presence.
• The enzyme electrode exhibits well-defined catalytic cyclic voltammograms in the presence of glucose.
• The developed biosensor shows analytical performance comparable to advanced second-generation biosensors without covalent linking.

Conclusions:

• The proposed protocol enables effective wiring of glucose oxidase with immobilized mediators, facilitating reagentless sensing.
• Unsubstituted phenothiazine is a promising new mediator for glucose biosensors.
• The developed biosensor offers long-term operational stability and high analytical performance, surpassing the need for covalent immobilization.