Graphene-based liquid-gated field effect transistor for biosensing: Theory and experiments.

Area of Science:

• Materials Science
• Nanotechnology
• Biomedical Engineering

Background:

• Field-effect transistors (FETs) based on reduced graphene-oxide (rGO) are promising for biosensing.
• Understanding their electrical properties and performance in liquid environments is crucial for application development.

Purpose of the Study:

• To experimentally and theoretically characterize rGO-based FETs for biosensing applications.
• To analyze device performance under varying ionic strength and pH conditions.
• To evaluate the FETs' capability for detecting biomolecules using Langmuir binding theory.

Main Methods:

• Fabrication of rGO-based FETs using wet-chemically synthesized graphene.
• Testing device performance in liquid gate mode with varying electrolyte ionic strength and pH.
• Experimental and theoretical analysis of Debye length dependence.
• Biomolecule sensing of bovine serum albumin (BSA) using immobilized anti-BSA antibodies.
• Analysis of binding kinetics using Langmuir binding theory.

Main Results:

• Experimental and theoretical confirmation of Debye length dependence, defining device applicability limits.
• Demonstrated sensing of BSA with binding coefficients consistent with literature values.
• Achieved a Limit of Detection (LOD) in the picomolar range for BSA-anti-BSA interaction.
• rGO-FETs exhibited high electron and hole mobility, enabling sensitivity to low potential changes.

Conclusions:

• The presented rGO-FETs offer high reproducibility and sensitivity for biosensing.
• The devices show excellent agreement between experimental results and theoretical predictions.
• The developed approach confirms the applicability of rGO-FETs for sensitive biomolecule detection.