Developing a Rapid, Simple-to-use Sensory Platform for Detection of Ultralow Concentration of SARS-CoV-2 Viral Particles Enabled by Electrophoretic Enhancement and Redox Cycling

Abstract: COVID-19 caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) remains an extraordinary global health crisis in the modern history. Meeting the testing needs for clinical diagnosis remains an unmet global challenge. Simple-to-use, sensitive, and rapid diagnostics are therefore urgently needed for early diagnosis of infection. The objective of this research is to design and demonstrate proof-of-principle of a novel low-cost and simple-to-use electrochemical sensing platform to enable rapid, ultrasensitive and accurate detection of SARS-CoV-2 virions in saliva (with accuracy ≥ 90% and total assay time < 30 min). We propose to achieve high sensitivity through two complementary signal amplification schemes, by electrophoretic concentration of virus-magnetic nanoparticle (mNP) conjugates by applying a small voltage on a set of electrodes with sub-micrometer gap, and amplifying electrochemical current through redox cycling between the same set of electrodes. Importantly, the proposed platform is suitable for commercialization by leveraging a low-cost and scalable fabrication method to create the sensor arrays without using expensive and non-scalable nanofabrication techniques. Fast, sensitive, and accurate detection of viral particles enables better surveillance and control of spread of the infection. The proposed platform is simple-to-use and suitable for point-of-care applications by eliminating tedious RNA extraction steps as in RT-PCR methods. It can enable high-throughput testing by creating sensor array on the same chip with small footprint to simultaneously analyze a multitude of sample droplets. The proposed sensory platform can also be expanded to detect other infectious pathogens, including Dengue and Influenza viruses, bacterial pathogens, etc.