Polydopamine-based electrochemical immunosensor for sensitive and selective detection of cotinine

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Nanotechnology

Background:

• Tobacco use is a major global health concern, necessitating accurate exposure monitoring.
• Cotinine, a nicotine metabolite, serves as a key biomarker for tobacco exposure.
• Existing detection methods may lack sensitivity, specificity, or cost-effectiveness.

Purpose of the Study:

• To develop and validate a sensitive and specific electrochemical biosensor for cotinine detection.
• To utilize polydopamine nanoparticles (PDA NPs) conjugated with anti-cotinine antibodies for enhanced detection.
• To assess the biosensor's performance in biological samples for potential point-of-care applications.

Main Methods:

• Fabrication of an electrochemical biosensor using PDA NPs conjugated with anti-cotinine antibodies.
• Characterization of nanoparticle functionalization using dynamic light scattering and Fourier transform infrared spectroscopy.
• Performance evaluation using differential pulse voltammetry, cyclic voltammetry, and electrochemical impedance spectroscopy in diluted human urine.

Main Results:

• Successful antibody conjugation and nanoparticle functionalization were confirmed.
• The biosensor demonstrated a wide linear response range (0.1-10,000 ng mL^-1) with a low detection limit (0.07 ng mL^-1).
• High specificity, good reproducibility in urine samples, and stability over six weeks were observed.

Conclusions:

• The developed PDA NPs-based electrochemical immunosensor is a promising tool for rapid, cost-effective cotinine detection.
• This biosensor shows potential for point-of-care monitoring of tobacco exposure in biological fluids.
• The study highlights the utility of functionalized nanomaterials in developing advanced biosensing platforms.