A Label-Free Immunosensor for IgG Based on an Extended-Gate Type Organic Field Effect Transistor

Area of Science:

• Biosensors
• Organic electronics
• Immunotechnology

Background:

• Immunoglobulin G (IgG) is a crucial biomarker in various physiological and pathological processes.
• Developing sensitive and efficient detection methods for IgG is essential for diagnostics.
• Organic field-effect transistors (OFETs) offer potential for low-cost, flexible biosensing platforms.

Purpose of the Study:

• To develop a novel biosensor for immunoglobulin G (IgG) detection.
• To utilize an extended-gate type organic field-effect transistor (OFET) for enhanced sensitivity.
• To demonstrate low-voltage operation of the developed immunosensor.

Main Methods:

• Immobilization of anti-IgG antibodies onto the extended-gate electrode of an OFET.
• Operation of the OFET-based biosensor at voltages below 3 V.
• Analysis of OFET transfer curves in response to varying IgG concentrations in the presence of bovine serum albumin.

Main Results:

• The biosensor exhibited a negative shift in the OFET transfer curve with increasing IgG concentration, indicating successful detection.
• A linear detection range from 0 to 10 µg/mL for IgG was achieved.
• A low detection limit of 0.62 µg/mL (4 nM) for IgG was determined.
• The biosensor demonstrated effective performance in the presence of a bovine serum albumin interferent.

Conclusions:

• The developed extended-gate OFET biosensor is effective for sensitive IgG detection.
• The biosensor operates at low voltages, making it suitable for portable applications.
• This technology opens new avenues for OFET-based immunosensing platforms.