Multiplexed COVID-19 antibody quantification from human sera using label-free nanoplasmonic biosensors

Area of Science:

• Nanotechnology
• Biomedical Engineering
• Immunology

Background:

• Serological assays are crucial for assessing COVID-19 immunity but are typically centralized.
• Current antibody testing limitations hinder widespread access and timely healthcare decisions.
• Point-of-care diagnostics are needed to broaden access to immune status information.

Purpose of the Study:

• To develop a multiplexed, label-free nanoplasmonic biosensor for point-of-care antibody profiling.
• To enable simultaneous quantification of SARS-CoV-2 specific antibodies from small serum volumes.
• To provide a sensitive and specific tool for diagnosing past COVID-19 infections.

Main Methods:

• Developed a multiplexed, label-free nanoplasmonic biosensor using optical imaging.
• Simultaneously quantified antibodies against SARS-CoV-2 spike and nucleocapsid proteins.
• Employed multivariate data processing and multi-color imaging for enhanced dynamic range (0.1-100 µg/mL).

Main Results:

• Successfully measured antigen-specific antibody responses in COVID-19 patient sera.
• Demonstrated highly sensitive and specific diagnosis of past infection.
• Achieved good concordance (R∼0.87) when benchmarked against an electrochemiluminescence assay.

Conclusions:

• The nanoplasmonic biosensor offers a promising solution for point-of-care antibody testing.
• This technology can significantly improve accessibility for epidemiological sero-profiling and vaccine studies.
• The biosensor facilitates rapid and reliable assessment of immune status against COVID-19.