Scientists at the University of California, Santa Cruz, have developed a new chip-based ultrasensitive antigen test. The test can detect SARS-CoV-2 and influenza A virus in nasal swab samples. The test can differentiate between individual viral antigens of Covid-19 and flu in swab specimens, according to the researchers. It has the potential to be developed into a molecular diagnostic test for use in point-of-care settings.
The gold standard for Covid-19 detection is currently polymerase chain reaction (PCR) technology. Tiny amounts of the virus’ genetic material are amplified, and specimens are analysed in centralised laboratories. According to reports, the latest chip-based antigen test has a high sensitivity. It facilitates the simultaneous testing of multiple viruses from a single sample. This is important because diseases such as Covid-19 and flu have similar symptoms.
The research team created a fluorescent probe that was bright enough to optically distinguish individual markers on the chip in order to establish this antigen test. The test makes use of an immunoassay technique known as an “antibody sandwich.” Antibodies specific for the target antigen are bound to magnetic microbeads in this test, allowing any target antigen in the sample to bind to the beads. Later, a fluorescent marker is attached to a second antibody, which binds to any target antigen present on the beads.