RapidPlex aims for swift home COVID-19 tests

This is the aim of researchers at Caltech who have developed a multiplexed test with a low-cost sensor that rapidly analyses small volumes of blood or saliva.

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The research was conducted in the lab of Wei Gao, assistant professor in the Andrew and Peggy Cherng department of medical engineering.

To make the sensors, a plastic sheet etched with a laser generates a 3D graphene structure with pores that create a large amount of surface area. This makes it sensitive enough to detect, with high accuracy, compounds that are only present in very small amounts. In this sensor, the graphene structures are coupled with antibodies, immune system molecules that are sensitive to specific proteins, like those on the surface of a COVID virus.

Previous versions of the sensor were impregnated with antibodies for the hormone cortisol, which is associated with stress, and uric acid, which at high concentrations causes gout. The new version of the sensor, which Gao has named SARS-CoV-2 RapidPlex, contains antibodies and proteins that allow it to detect the presence of the virus itself; antibodies created by the body to fight the virus; and chemical markers of inflammation, which indicate the severity of the COVID-19 infection.