Label-free biosensors based on aptamer-modified graphene field-effect transistors

Area of Science:

• Materials Science
• Biotechnology
• Electrical Engineering

Background:

• Graphene field-effect transistors (G-FETs) offer high sensitivity for biosensing.
• Label-free detection methods are crucial for real-time biological monitoring.
• Immunoglobulin E (IgE) is a key biomarker in allergic responses.

Purpose of the Study:

• To develop a label-free immunosensor using aptamer-modified G-FETs.
• To demonstrate the selective electrical detection of IgE protein.
• To evaluate the performance and affinity of the aptamer-G-FET system.

Main Methods:

• Immobilization of IgE aptamers onto a graphene surface.
• Fabrication and characterization of the aptamer-modified G-FET.
• Atomic force microscopy (AFM) for surface analysis.
• Electrical measurements to detect varying concentrations of IgE.

Main Results:

• Successful immobilization of IgE aptamers on graphene confirmed by AFM.
• Selective electrical detection of IgE protein by the aptamer-G-FET.
• Estimation of the dissociation constant (Kd) at 47 nM, indicating high affinity.

Conclusions:

• The aptamer-modified G-FET is a viable platform for label-free immunosensing.
• The developed sensor exhibits high selectivity and affinity for IgE detection.
• G-FETs show significant potential for application in sensitive biological sensor development.