Coulometric D-fructose biosensor based on direct electron transfer using D-fructose dehydrogenase

Area of Science:

• Electrochemistry
• Biosensors
• Biocatalysis

Background:

• Direct electron transfer (DET) in biosensors offers advantages over mediator-based systems.
• D-fructose dehydrogenase (FDH) is a key enzyme for d-fructose detection.
• Mediator-free biosensors minimize potential interference and simplify assay design.

Purpose of the Study:

• To develop a batch-type coulometric biosensor for d-fructose detection.
• To utilize direct electron transfer of FDH immobilized on nanostructured carbon electrodes.
• To demonstrate the biosensor's applicability for analyzing d-fructose and related compounds in real samples.

Main Methods:

• Immobilization of d-fructose dehydrogenase (FDH) on nanostructured carbon electrodes.
• Coulometric measurement of d-fructose oxidation via direct electron transfer.
• Application of specific hydrolases for oligosaccharide and polysaccharide analysis.
• Subtraction of background signal from FDH-free electrodes to eliminate interferences.

Main Results:

• The biosensor demonstrated accurate coulometric measurements of d-fructose from 1 to 100 mM.
• Catalytic current density was enhanced by using nanostructured carbon particle-modified electrodes.
• The method successfully determined d-fructose in beverages and analyzed sucrose using invertase.
• Interference from electroactive compounds like ascorbate was effectively managed.

Conclusions:

• A mediator-free coulometric d-fructose biosensor based on FDH DET was successfully developed.
• The nanostructured electrode design enhanced sensitivity and accuracy.
• The biosensor is versatile, applicable to free d-fructose and d-fructose-containing carbohydrates.
• This method provides a reliable tool for d-fructose determination in complex matrices.