Concept: A research team from the California Institute of Technology (Caltech) has created a laser-drilled, coated graphene sensor that can perform on-the-spot testing of the COVID-19. The electronic-based rapid-response detection unit called SARS-CoV-2 RapidPlex delivers results in approximately 10 minutes, even the asymptotic individual suffering from COVID-19.

Nature of Disruption: The SARS-CoV-2 RapidPlex unit, a biomedical tag, incorporates several low-cost sensors accompanied by data processing and reporting to the user’s smartphone. It electrochemically quantifies three important molecular biomarkers, SARS-CoV-2 nucleocapsid protein, anti-spike immune response proteins IgG and IgM and C-reactive protein (CRP). For medical research, the device is trained with a few saliva and blood samples collected from people who tested positive or negative for COVID-19. The platform uses antibodies immobilized and captured antigens to create micropores on graphene electrodes that have been laser engraved. This method produces a large sensor surface area to make it sufficiently sensitive to detect substances that are only present in minuscule quantities. There are four graphene operating electrodes (WEs), an Ag/AgCl reference electrode (RE), and a graphene counter electrode in the RapidPlex sensor array (CE). All of them are patterned through CO2 laser engraving on a polyimide (PI) substrate, which is a simple, high-throughput and cost-effective production process. In order to anchor the receptors to the graphene substrate, the sensor coating uses 1-Pyrenebutyric acid (PBA) as the linker. To electrochemically characterize the sensor’s processes, the unit used differential pulse voltammetry (DPV) and open-circuit potential-electrochemical impedance spectroscopy (OCP-EIS).

Outlook: It is difficult to spot the carrier of the COVID-19 virus, as an asymptotic person can spread the virus showing no symptoms of the disease. Therefore, the development of tests that can quickly recognize pathogens in asymptomatic carriers is a critical part of the global effort to stem the spread. Also, established COVID-testing technologies usually take hours or even days to produce results. Caltech’s low-cost sensor can enable the at-home diagnosis of the COVID-19 infection through rapid analysis. SARS-CoV-2 RapidPlex unit successfully detects infection biomarkers in COVID-19-positive patient serum and saliva samples, and the results of CRP are well-correlated with the severity of symptoms. The institute has planned to further modify the device for testing other types of infectious disease at home.

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