Electrochemical immunosensor for rapid and specific detection of SARS-CoV-2

Abstract

ABSTRACT : COVID-19 is an emerging infection produced by the etiologic agent coronavirus type 2, causing severe acute respiratory syndrome (SARS-CoV-2). It appeared in China in late 2019 and then spread worldwide. Timely detection is imperative to reduce the speed of contagion and contribute to the traceability of the disease. Currently, diagnostics is done by reverse transcription-polymerase chain reaction (RT-PCR) that detects the genetic material of the virus requiring robust equipment and trained personnel, or by antigen and serological tests that detect the structural proteins of the virus and antibodies generated by the host, respectively, but with cross-reactivity and low sensitivity. Biosensors can take advantage of the high affinity of biorecognition molecules and unique material properties for rapid, specific and highly sensitive detection of SARS-CoV-2, offering a promising solution to the limitations of conventional methods. In this work, an electrochemical immunosensor has been developed for the rapid and trustworthy detection of SARS-CoV-2. The immunosensor captured the protein S from the virus between magnetic beads functionalized with primary antibodies and specific secondary antibodies, which were labeled with a reporter enzyme. The system was confined to the surface of screen-printed electrodes, and the enzymemediator interaction signal was recorded in a portable potentiostat. The biosensor was characterized in terms of analytical performance and detected commercial protein S and protein S from viral particles, pseudovirions and samples from patients in concentrations of clinical relevance (22.5 ng/mL-2 µg/mL), opening the possibility of SARS-CoV-2 detection at the point of care.