Biofunctionalized gold nanoparticle-conducting polymer nanocomposite based bioelectrode for CRP detection

Area of Science:

• Electrochemistry
• Nanomaterials Science
• Biomedical Engineering

Background:

• C-reactive protein (CRP) is a key biomarker for inflammation and cardiovascular disease.
• Accurate and sensitive detection of CRP is crucial for early diagnosis and monitoring of various health conditions.
• Existing CRP detection methods may lack sensitivity, speed, or cost-effectiveness.

Purpose of the Study:

• To develop and characterize a novel electrochemical impedance immunosensing platform for sensitive CRP detection.
• To immobilize anti-CRP antibodies onto a functionalized gold nanoparticle-polypyrrole nanocomposite film.
• To evaluate the performance of the developed immunosensor for CRP quantification in phosphate-buffered saline (PBS).

Main Methods:

• Fabrication of a nanocomposite film using electrochemically deposited gold nanoparticles (Au) capped with 3-mercaptopropionic acid (MPA) and polypyrrole (PPy) on an indium tin oxide (ITO) substrate.
• Site-specific immobilization of anti-CRP antibodies (Ab-αCRP) onto the carboxyl groups of the nanocomposite film using carbodiimide chemistry.
• Characterization of the nanocomposite film using atomic force microscopy (AFM), high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FTIR), and electrochemical techniques.
• Electrochemical impedance spectroscopy (EIS) analysis using a modified Randles circuit to determine electron transfer resistance (R et) and other parameters.

Main Results:

• The Au(MPA)-PPy nanocomposite film exhibited a porous morphology, confirmed by AFM, HRTEM, and an electrochemical heterogeneity gauge (CPE exponent n=0.56).
• A stable immobilization of Ab-αCRP was achieved via an acyl amino ester linkage.
• A linear correlation was observed between the increase in electron transfer resistance (∆R et) and the logarithm of CRP antigen (Ag-αCRP) concentration over a range of 10 ng/mL to 10 μg/mL.
• The immunosensor demonstrated a high sensitivity of 46.27 Ω cm²/decade for CRP detection in PBS (pH 7.4).

Conclusions:

• The developed electrochemical impedance immunosensing method utilizing an Au(MPA)-PPy nanocomposite film is effective for sensitive and specific detection of CRP.
• The functionalized nanocomposite platform provides a robust surface for antibody immobilization and enhances the electrochemical signal.
• This approach offers a promising tool for the quantitative analysis of CRP in biological samples, potentially aiding in disease diagnosis.