Cross-linked redox gels containing glucose oxidase for amperometric biosensor applications

Area of Science:

• Electrochemistry
• Biomaterials Science
• Enzyme Engineering

Background:

• Enzymes like glucose oxidase can be electrically wired to electrodes using redox polymers for biosensing.
• Existing methods often require membranes to immobilize enzymes and redox mediators.

Purpose of the Study:

• To develop novel cross-linked, electroactive polymer films for amperometric biosensors.
• To improve enzyme immobilization and electron transfer efficiency in biosensor design.

Main Methods:

• Synthesized a cross-linkable poly(vinylpyridine) complex with an osmium redox center.
• Functionalized the polymer with hydrophilic groups and active esters for enzyme and cross-linker attachment.
• Formed rugged, cross-linked films on electrodes in the presence of glucose oxidase and triethylenetetraamine.

Main Results:

• The resulting polymer films enabled direct electrical wiring of glucose oxidase, eliminating the need for membranes.
• Achieved rapid glucose response times of less than 10 seconds.
• Observed Michaelis constants (Km') of 7.3 mM and current densities (jmax) between 100-800 microA/cm2, with reduced currents in the presence of oxygen.

Conclusions:

• The developed polymer system effectively creates robust, electroactive biosensor films.
• The direct enzyme-electrode wiring enhances electron transfer but suggests only partial enzyme engagement with the electrode.
• This approach offers a promising alternative for amperometric biosensor fabrication.