Electrochemical lateral-flow device for rapid COVID-19 antigen-diagnostic testing

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Infectious Disease Diagnostics

Background:

• Antigen test kits (ATKs) are widely used for COVID-19 screening due to their ease of use.
• Standard ATKs suffer from low sensitivity, limiting their ability to detect low SARS-CoV-2 concentrations.
• There is a need for more sensitive and quantitative diagnostic tools for COVID-19.

Purpose of the Study:

• To develop a highly sensitive and selective device for COVID-19 diagnosis by integrating ATK principles with electrochemical detection.
• To enable quantitative assessment of SARS-CoV-2 antigen levels using a smartphone interface.
• To improve the accuracy and reliability of rapid COVID-19 screening.

Main Methods:

• An electrochemical test strip (E-test strip) was created by incorporating a screen-printed electrode into a lateral-flow device.
• The device utilizes the binding affinity between SARS-CoV-2 antigen and ACE2.
• Ferrocene carboxylic acid-labeled antibodies detect the antigen, generating an electrochemical signal proportional to viral load.

Main Results:

• The E-test strip achieved a low limit of detection (LOD) of 2.98 pg/mL within 12 minutes.
• Smartphone-based quantitative assessment showed signal intensity directly correlated with SARS-CoV-2 antigen concentration.
• Testing with nasopharyngeal samples demonstrated results consistent with the gold standard (RT-PCR).

Conclusions:

• The developed sensor offers a rapid, simple, and inexpensive method for sensitive and selective COVID-19 assessment.
• This technology provides accurate diagnostic verification, overcoming the limitations of conventional ATKs.
• The device holds potential for professional use in clinical settings and public health screening.