Highly stable electrochemical immunosensor for carcinoembryonic antigen.

Area of Science:

• Electrochemistry
• Nanomaterials Science
• Biomedical Engineering

Background:

• Long-term stability of sensing interfaces is critical for reliable biosensor performance.
• Existing biosensors often face challenges with interface degradation over time.
• Developing robust and stable biosensing platforms is essential for clinical applications.

Purpose of the Study:

• To develop a novel, stable gold nanoparticle (AuNP)-modified glassy carbon (GC) electrode interface (GC-Ph-AuNP) for detecting carcinoembryonic antigen (CEA).
• To investigate the stability and performance characteristics of the developed immunosensor.
• To establish a versatile immobilization method for constructing various immunosensors.

Main Methods:

• Modification of glassy carbon electrodes with 1,4-phenylenediamine to create a stable layer.
• Binding of gold nanoparticles (AuNPs) to the modified GC electrode via Au-S bonds.
• Direct adsorption of anti-CEA antibodies onto the immobilized AuNPs to form the immunosensor.
• Electrochemical detection of CEA using the fabricated GC-Ph-AuNP immunosensor.

Main Results:

• The developed GC-Ph-AuNP immunosensor demonstrated a wide linear detection range for CEA from 10 fg mL⁻¹ to 100 ng mL⁻¹.
• A low detection limit of 3 fg mL⁻¹ (S/N=3) was achieved.
• The immunosensor exhibited excellent stability, with only a 4% increase in current after one month.
• High sensitivity, selectivity, and stability were confirmed for the GC-Ph-AuNP immunosensor.

Conclusions:

• The novel GC-Ph-AuNP interface provides a highly stable and sensitive platform for CEA detection.
• The developed immunosensor exhibits superior performance characteristics, including a wide linear range and low detection limit.
• The immobilization strategy is versatile and can be broadly applied to the fabrication of other immunosensors for different biomarkers.