Dual-Mode Graphene Field-Effect Transistor Biosensor with Isothermal Nucleic Acid Amplification.

Area of Science:

• Biotechnology
• Nanotechnology
• Medical Diagnostics

Background:

• Limited access to diagnostic testing, especially in remote and low-resource areas, hinders effective infectious disease management.
• Existing diagnostic methods like RT-PCR face challenges in accessibility and throughput for widespread point-of-care applications.
• Loop-mediated isothermal amplification (LAMP) shows promise for rapid diagnostics but requires enhanced sensitivity for detecting low viral concentrations.

Purpose of the Study:

• To develop a highly sensitive, dual-mode biosensor for rapid detection of viral nucleic acids.
• To integrate loop-mediated isothermal amplification (LAMP) with a graphene-based field-effect transistor (G-FET) biosensor.
• To evaluate the biosensor's performance in resource-constrained settings for point-of-care diagnostics.

Main Methods:

• Fabrication of a transparent graphene microelectrode array on a glass substrate for the G-FET biosensor.
• Integration of the G-FET biosensor with loop-mediated isothermal amplification (LAMP) for sample analysis.
• Dual-mode detection utilizing observable color changes and Dirac point voltage measurements of LAMP products.

Main Results:

• The dual-mode G-FET biosensor achieved sensitive detection of LAMP products in under 30 minutes.
• The biosensor demonstrated accurate detection even in samples with low viral concentrations.
• Colorimetric detection was observable with the naked eye, enhancing usability.

Conclusions:

• The developed dual-mode G-FET biosensor offers a sensitive and rapid alternative for viral detection, including SARS-CoV-2.
• This technology is particularly suitable for point-of-care testing in resource-limited environments and developing countries.
• The combination of speed, sensitivity, and visual detection expands the applicability of advanced diagnostics in diverse settings.