COVID-19 test: no sample preparation required

Written by Alex Hyde, Future Science Group

Researchers from the Korea Research Institute of Chemical technology (Daejeon, Republic of Korea) and Korea Basic Science Institute (Cheongju, Republic of Korea) have developed an antibody test to detect SARS-CoV-2 based on a field-effect transistor. The test can distinguish between nasopharyngeal samples from healthy individuals and those from COVID-19 patients with no sample preparation required.

At present, the majority of COVID-19 diagnostic tests rely on RT-PCR to amplify SARS-CoV-2 viral RNA from patient swabs. Following the amplification of genetic material, the virus can be detected. Such tests can take hours from sample acquisition to result, requiring multiple steps and sample preparation procedures.

A team of researchers, led by Edmond Changkyun Park and Seung Il Kim (Korea Basic Science Institute) focused their efforts on developing a rapid diagnostic test for COVID-19 that does not require sample preparation.

The newly developed test, reported in ACS Nano, is based on a graphene platform with high electrical conductivity known as a field-effect transistor. The surface of the graphene is modified to include antibodies for the SARS-CoV-2 spike protein. Binding of the SARS-CoV-2 virus to the antibodies on the surface of the graphene causes a change in electrical current which can then be detected.

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During the evaluation of the test, the team demonstrated its ability to detect SARS-CoV-2 directly from nasopharyngeal swab samples in buffer solution. Although the test successfully discriminates between nasopharyngeal swabs from healthy individuals and COVID-19 patients with no sample preparation, it is approximately 2–4 times less sensitive than a standard RT-PCR test.

Researchers believe that investigating different materials could lead to improvements in the signal-to-noise ratio. If successful, the test could facilitate more rapid COVID-19 testing in the future.

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Sources: Seo G, Lee G, Kim MJ et al. Rapid detection of COVID-19 causative virus (SARS-CoV-2) in human nasopharyngeal swab specimens using field-effect transistor-based biosensor. ACS Nano doi:10.1021/acsnano.0c02823 (2020) (Epub ahead of print);

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