A mediatorless and label-free amperometric immunosensor for detection of h-IgG

Area of Science:

• Electrochemistry
• Biosensors
• Nanomaterials

Background:

• Development of sensitive and specific biosensors is crucial for early disease detection.
• Mediatorless and label-free immunosensors offer advantages in simplicity and reduced cost.
• Gold nanoparticles and L-cysteine coatings enhance electrode performance in electrochemical sensing.

Purpose of the Study:

• To propose a novel experimental methodology for a mediatorless and label-free immunosensor.
• To utilize electrochemical detection of dopamine for signal generation in an immunosensor.
• To establish a quantitative detection method for human immunoglobulin G (h-IgG).

Main Methods:

• Immobilization of antibodies on a gold nanoparticle/L-cysteine coated electrode (nano-Au/L-cysteine electrode).
• Utilizing differential pulse voltammetry (DPV) for electrochemical signal detection.
• Employing an unenzymatic-labeling procedure with dopamine as the substrate.

Main Results:

• The developed immunosensor demonstrated excellent electrochemical response to dopamine.
• Incubation with h-IgG solution partially inhibited the electrocatalytic behavior towards dopamine.
• A linear decrease in amperometric response was observed with increasing h-IgG concentration from 0.82 to 90 ng/mL.

Conclusions:

• The proposed nano-Au/L-cysteine electrode serves as an effective platform for a label-free immunosensor.
• The immunosensor enables sensitive and quantitative detection of h-IgG through electrochemical signal modulation.
• This methodology offers a promising approach for developing advanced biosensing platforms.