New antibody detection method for coronavirus that does not require a blood sample

Despite significant and stunning advances in vaccine technology, the COVID-19 global pandemic is not over. A key challenge in limiting the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is identifying infected individuals. Researchers from Japan have developed a new antibody-based method for the rapid and reliable detection of SARS-CoV-2 that does not require a blood sample. Study is published in Scientific Reports.

An alternative and complementary method for the confirmation of COVID-19 infection involves the detection of SARS-CoV-2-specific antibodies. Testing strips based on gold nanoparticles are currently in widespread use for point-of-care testing in many countries. They produce sensitive and reliable results within 10–20 minutes, but they require blood samples collected via a finger prick using a lancing device. This is painful and increases the risk of infection or cross-contamination, and the used kit components present a potential biohazard risk.

Researchers said to develop a minimally invasive detection assay that would avoid these drawbacks, they explored the idea of sampling and testing the interstitial fluid (ISF), which is located in the epidermis and dermis layers of human skin. Although the antibody levels in the interstitial fluid are approximately15%–25% of those in blood, it was still feasible that anti-SARS-CoV-2 IgM/IgG antibodies could be detected and that ISF could act as a direct substitute for blood sampling.

After demonstrating that interstitial fluid could be suitable for antibody detection, the researchers developed an innovative approach to both sample and test the interstitial fluid. Firstly they developed biodegradable porous microneedles made of polylactic acid that draws up the interstitial fluid from human skin. Then constructed a paper-based immunoassay biosensor for the detection of SARS-CoV-2-specific antibodies. By integrating these two elements, the researchers created a compact patch capable of on-site detection of the antibodies within 3 minutes (result from in vitro tests).

This novel detection device has great potential for the rapid screening of COVID-19 and many other infectious diseases that is safe and acceptable to patients. It holds promise for use in many countries regardless of their wealth, which is a key aim for the global management of infectious disease concluded the authors.

Reference: Bao, L., Park, J., Qin, B. et al. Anti-SARS-CoV-2 IgM/IgG antibodies detection using a patch sensor containing porous microneedles and a paper-based immunoassay. Sci Rep 12, 10693 (2022). https://doi.org/10.1038/s41598-022-14725-6.