Design of a stable charge transfer complex electrode for a third-generation amperometric glucose sensor

Area of Science:

• Electrochemistry
• Biosensor Technology
• Materials Science

Background:

• Direct electron transfer in biosensors is crucial for improved performance.
• Organic charge transfer complexes (CTCs) offer unique electronic properties for electrode modification.
• Developing stable and sensitive amperometric biosensors remains a key challenge.

Purpose of the Study:

• To develop a stable charge transfer complex (CTC) electrode for direct flavoprotein oxidation.
• To fabricate a third-generation amperometric biosensor with enhanced performance.
• To investigate the stability and operational characteristics of the novel biosensor.

Main Methods:

• Grown tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) CTC on a shapable electroconductive (SEC) film with a tree-shaped crystal structure.
• Immobilized glucose oxidase (GOx) onto the CTC surface and cross-linked with glutaraldehyde.
• Stabilized the enzyme and electrode structure using cross-linked gelatin.

Main Results:

• Achieved direct oxidation of glucose oxidase at the CTC surface, leading to significantly improved sensor performance.
• The biosensor operates effectively at low potentials (0.0–0.25 V vs Ag/AgCl) with a maximum current density of 1.8 mA/cm².
• Demonstrated excellent stability, with negligible interference from oxygen and physiological fluids, and prolonged working and shelf life (over a year when stored).

Conclusions:

• The novel TTF-TCNQ CTC electrode facilitates direct flavoprotein oxidation, enabling high-performance amperometric biosensors.
• The fabricated glucose biosensor exhibits remarkable stability, sensitivity, and a wide linear range.
• This approach offers a promising strategy for developing robust and reliable biosensing platforms.