COVID-19 is detected in under three minutes thanks to a skin patch test

COVID-19 is detected in under three minutes thanks to a skin patch test ...

A simple and reliable skin-patch test can now detect the COVID-19 virus and other infectious agents in under three minutes, without the need to take blood. This approach addresses a current challenge in identifying infected individuals who are averse to blood tests, and might help prevent the spread of the epidemic.

In an article in the journal Scientific Reports titled, AntiSARSCoV2 IgM/IgG antibodies detection using a patch sensor containing porous microneedles and a paper-based immunoassay, the details of the new test were published on July 1, 2022.

Asymptomatic individuals make up 1638% of the SARS-CoV-2 infected population, increasing the challenge of identifying infected individuals. The absence of appropriate and precise testing to detect the virus in all individuals continues to limit the global response to the epidemic.

SARS-CoV-2 is most commonly detected by RT-PCR on swab samples taken from the nose and throat, but these tests require long detection times, expensive equipment, and medical personnel, and are not feasible in regions where resources are limited.

COVID-19 infection can be detected through antibody tests (immunoassays) using blood samples taken from finger pricks by a lancing device. These popular point-of-care treatments require gold nanoparticle testing strips and involve risks of cross contamination and biohazard.

Immunochromatographic tests that detect anti-SARS-CoV-2 immunoglobulin M (IgM) and immunoglobulin G (IgG) can provide clinically relevant information regarding the course of COVID-19 infection, but invasive blood sampling is a major challenge.

According to the first author, we explored the possibility of sampling and testing interstitial fluid, which is located between the epidermis and dermis layers of human skin. Although antibody levels in the interstitial fluid are approximately1525% of blood, it was still feasible that anti-SARS-CoV-2 IgM/IgG antibodies could be detected, and that interstitial fluid could serve as a direct substitute for blood sampling.

PMNIA is a fast, painless, easy to use, and inexpensive alternative to SARS-CoV-2 IgM and IgG antibodies in dermal interstitial fluid [Bao et al, Sci Rep, 2022]We developed biodegradable porous microneedles made of polylactic acid that draws up the interstitial fluid from human skin, according to Beomjoon Kim, PhD, a professor at the University of Tokyo's department of mechanical and biofunctional systems who is

The authors used emulsion droplets to create continuous micropores, which they heated for half an hour at 180C to bind them together. They demonstrated that by a capillary action, interstitial fluid could be easily extracted from rat and pig skin, which was then used to model human skin.

The extracted interstitial fluid flows vertically into the attached nitrocellulose paper biosensor, where virus-specific antibodies are detected visually via a colored-based reaction (colorimetry).

The researchers demonstrated that anti-SARS-CoV-2 IgM and IgG levels as low as 3 and 7 ng/mL, respectively, can be detected with the skin patch test, which is much more economical and painless than previous commercially available lateral-flow immunochromatographic assays (LFIA).

The simplicity, simplicity, and minimally invasive nature of the compact anti-SARS-CoV-2 IgM/IgG biosensor device will lead to its widespread adoption, according to the authors. In addition to COVID-19, the device can be customized to rapidly screen several infectious agents and provide a complementary diagnostic test.

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