Researchers from the Institute of Industrial Science at the University of Tokyo, Japan, have developed a new antibody-based compact skin patch that can quickly detect the presence of SARS-CoV-2 virus without needing a blood sample.

The predominant Covid-19 detection method currently in use involves the collection of swab samples from the nose and throat.

This process is restricted by its high cost, long detection time, and requirement for specialised equipment and medical personnel, especially in countries where resources are limited.

An alternative method for Covid-19 detection is testing strips developed using gold nanoparticles that require blood samples collected through a finger prick with a lancet and provide results in ten to 20 minutes.

These tests are currently used for point-of-care testing to detect SARS-CoV-2-specific antibodies in many countries.

The Japanese researchers explored the sampling and testing of the interstitial fluid (ISF) in the epidermis and dermis layers of human skin to develop a minimally invasive detection test.

Institute of Industrial Science, University of Tokyo lead author Leilei Bao said: “Although the antibody levels in the ISF are approximately 15% to 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.”

Initially, the researchers developed biodegradable porous microneedles, made of polylactic acid, to draw ISF from the skin.

A paper-based immunoassay biosensor was later developed to detect the SARS-CoV-2-specific antibodies in the ISF.

By integrating the microneedles and biosensor, the researchers have created the compact patch system, which can detect antibodies within three minutes.