A solution processed carbon nanotube modified conducting paper sensor for cancer detection

Area of Science:

• Materials Science
• Nanotechnology
• Biomedical Engineering

Background:

• Conducting polymers like PEDOT:PSS are crucial for electronic applications.
• Carbon nanotubes (CNTs) enhance the conductivity and mechanical properties of materials.
• Developing cost-effective and sensitive biosensors for cancer biomarkers is a significant challenge.

Purpose of the Study:

• To fabricate a highly conductive and flexible paper-based biosensor using a PEDOT:PSS-CNT nano-composite.
• To functionalize the biosensor for the detection of carcinoembryonic antigen (CEA), a cancer biomarker.
• To evaluate the sensitivity and reliability of the developed biosensor for clinical applications.

Main Methods:

• Fabrication of a conducting paper (CP) using a PEDOT:PSS-CNT nano-composite via dip coating.
• Treatment with formic acid to enhance conductivity by removing PSS.
• Conjugation with anti-CEA antibodies for specific biomarker detection.
• Characterization using TEM, Raman, XRD, SEM, XPS, EIS, and amperometry.
• Validation using serum samples from cancer patients.

Main Results:

• Achieved high conductivity in the CNT/FA@CP (∼6.5 × 10^-4 to 2.2 × 10^-2 S cm^-1).
• Developed a sensitive biosensor with a detection limit of 7.8 μA ng^-1 ml cm^-2 in the physiological range (2-15 ng ml^-1) for CEA.
• Demonstrated the biosensor's performance using clinical serum samples, validating its accuracy against immunoassay techniques.

Conclusions:

• The developed PEDOT:PSS-CNT based conducting paper electrode is a low-cost, flexible, and environmentally friendly platform for biosensing.
• The formic acid treatment significantly enhances the conductivity of the nano-composite material.
• The biosensor exhibits high sensitivity and reliability for the quantitative detection of CEA in patient serum, showing potential for cancer diagnostics.