AFM-Modified Graphene Field-Effect Transistor for Sensitive Detection of Cardiac Troponin I.

Area of Science:

• Nanomaterials Science
• Biosensor Technology
• Surface Chemistry

Background:

• Graphene field-effect transistor (G-FET) biosensors require precise surface functionalization for optimal sensitivity and stability.
• Current functionalization methods often lack spatial control and can degrade graphene's electrical properties.

Purpose of the Study:

• To introduce an atomic force microscopy (AFM)-based precision functionalization technique for G-FET biosensors.
• To enable site-specific modification of graphene surfaces for stable aptamer immobilization.

Main Methods:

• Utilized an AFM-based approach with a biased probe tip for redox reactions.
• Performed site-specific immobilization of cardiac troponin I (cTnI)-specific aptamers on graphene.
• Fabricated G-FET biosensors using the precision functionalization technique.

Main Results:

• Achieved stable and localized immobilization of aptamers, minimizing graphene damage.
• Developed high-performance G-FET biosensors capable of detecting cTnI at concentrations as low as 0.01 pg/mL.
• Demonstrated linear resistance response and strong selectivity in concentration gradient assays.

Conclusions:

• The AFM-based precision functionalization technique offers a scalable solution for G-FET biosensor development.
• This method enables the construction of multiplexed biosensing platforms within a single sensor.
• The developed G-FET biosensors show significant potential for sensitive and selective cardiac biomarker detection.