Ultrasensitive biosensing on the zepto-molar level

Area of Science:

• Electrochemistry
• Biosensing
• Nanotechnology

Background:

• Achieving zepto-molar (10(-21) M) detection levels for analytes is a significant challenge in biosensing.
• Existing methods often lack the sensitivity required for detecting extremely low concentrations of biomolecules.

Purpose of the Study:

• To develop a highly sensitive bio-detector capable of zepto-molar level analyte detection.
• To investigate the mechanism of current amplification using a gating voltage applied to immobilized enzymes.

Main Methods:

• Utilized a field-effect bio-detector with immobilized enzymes (glucose oxidase and alcohol dehydrogenase) on the working electrode.
• Applied a gating voltage to the enzyme-electrode interface to modify the tunnel barrier and amplify biocatalytic current.
• Demonstrated detection using glucose oxidase-glucose and alcohol dehydrogenase-ethanol systems.

Main Results:

• Achieved zepto-molar detection resolution for glucose, detecting down to 30 individual glucose molecules.
• Observed distinct responses to incremental changes in analyte concentration (30 molecules).
• Confirmed that enzyme biospecificity is maintained under the applied electric field.

Conclusions:

• The field-effect bio-detector enables unprecedented zepto-molar sensitivity for analyte detection.
• Gating voltage-induced electric fields at the solution-electrode interface are key to biocatalytic current amplification.
• This technology holds promise for highly sensitive and specific biosensing applications.