Disposable and eco-friendly electrochemical immunosensor for rapid detection of SARS-CoV-2

This study describes the development of a simple, disposable, and eco-friendly electrochemical immunosensor for rapid detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Electrochemical devices were manufactured by stencil-printing using low-cost materials such as polyester sheets, graphite flakes, and natural resin. The immunosensor comprises gold nanoparticles stabilized with cysteamine, glutaraldehyde, anti-SARS-CoV-2 S protein monoclonal antibody (Ab1) as the biological receptor and bovine serum albumin as a protective layer. The COVID-19 diagnostic was based on rapid square wave voltammetry measurements (15 min) using [Fe(CN)6]3-/4- as a redox probe. The method presented a linear response in the concentration range from 250 pg mL−1 to 20 μg mL−1 S protein, with a limit of detection of 36.3 pg mL−1. The proposed immunosensor was stable for up to two weeks when stored at 4 °C and it demonstrated excellent clinical performance in diagnosing COVID-19 when applied to a panel of 44 undiluted swab samples collected from symptomatic patients. In comparison with results obtained through the quantitative reverse transcription polymerase chain reaction method, the proposed immunosensor offered 100 % accuracy, thus emerging as a powerful alternative candidate for routine and decentralized testing, which can be helpful in controlling the COVID-19 outbreak. [Display omitted] •A novel electrochemical immunosensor for rapid detection of SARS-CoV-2 was developed.•Stencil-printed electrochemical sensors were manufactured using polyester sheets, graphite flakes, and natural resin.•A linear behavior was observed in the S protein concentration range from 250 pg mL−1 to 20 μg mL−1.•44 undiluted swab samples collected from symptomatic patients were successufully analyzed.•A 100 % accuracy was achieved when compared with the results obtained by RT-qPCR.