Analytical characterization of label-free immunosensor subsystems based on multi-walled carbon nanotube...

Area of Science:

• Electrochemistry
• Nanomaterials Science
• Biomedical Engineering

Background:

• Label-free electrochemical immunosensors offer sensitive and direct detection of biomarkers.
• Prostate-specific antigen (PSA) is a key biomarker for prostate cancer screening.
• Multi-walled carbon nanotubes (MWCNTs) enhance electrode performance due to their unique electrical properties.

Purpose of the Study:

• To characterize antigen-antibody interactions for a label-free electrochemical immunosensor.
• To develop a sensitive detection method for PSA using a modified gold electrode.
• To evaluate the performance of MWCNT-modified electrodes for immunosensing applications.

Main Methods:

• Functionalization of MWCNTs with carboxyl groups (-COOH) confirmed by FTIR spectroscopy.
• Atomic Force Microscopy (AFM) and Raman spectroscopy to verify antibody (Ab) immobilization on the MWCNT-modified gold electrode.
• Electrochemical characterization using cyclic voltammetry in a potassium ferricyanide solution.

Main Results:

• Successful functionalization and immobilization of antibodies on the MWCNT-modified gold electrode.
• Demonstrated a linear electrochemical response to PSA concentrations ranging from 2 to 40 ng/mL.
• Achieved a low limit of detection (LOD) of 0.56 ng/mL for PSA.

Conclusions:

• The MWCNT array-modified gold electrode is effective for label-free electrochemical detection of PSA.
• The developed immunosensor shows high sensitivity and a low detection limit, suitable for clinical applications.
• This approach provides a promising platform for developing advanced electrochemical biosensors.