Impedance-Based Neutralizing Antibody Detection Biosensor with Application in SARS-CoV-2 Infection

Area of Science:

• Biomedical Engineering
• Immunotechnology
• Infectious Disease Diagnostics

Background:

• Serum neutralizing antibody (NAb) concentration is a key indicator of protective immunity against COVID-19.
• NAbs target the SARS-CoV-2 receptor-binding domain (RBD), preventing interaction with human ACE2.
• Accurate and rapid NAb quantification is crucial for managing COVID-19 vaccination strategies.

Purpose of the Study:

• To develop and validate an inexpensive, rapid, sensitive, and quantifiable impedance-based immunosensor for evaluating COVID-19 NAbs.
• To investigate the underlying detection mechanisms of the developed immunosensor.
• To establish the analytical performance of the immunosensor for NAb detection.

Main Methods:

• Development of an impedance-based immunosensor utilizing human ACE2 (hACE2) immobilization.
• Experimental determination of the sensor's limit of detection using IgG-anti-IgG interactions.
• Analysis of AC electrokinetic transport and molecular diffusion using scaling analysis and numerical simulations.
• Testing the sensor with viral RBD buffers containing varying concentrations of NAbs.

Main Results:

• The sensor's detection mechanism is primarily governed by biomolecule diffusion onto the electrode surface.
• The immunosensor demonstrated NAb detection capabilities within an analytical measuring range of 45 ng/mL to 185 ng/mL.
• The developed sensor provides fast and cost-effective NAb quantification.

Conclusions:

• The developed impedance-based immunosensor offers a viable tool for assessing COVID-19 NAb levels.
• This technology can assist in determining the need for subsequent COVID-19 vaccine doses.
• The sensor's low cost and rapid results support its potential for widespread clinical application.