Biossensor eletroquímico a base de grafeno induzido a laser para diagnóstico da COVID-19: detecção de anticorpos biomarcadores anti-SARS-CoV-2

Abstract

The severe acute respiratory syndrome originated by the new coronavirus ((nCoV) (SARS-CoV-2) that emerged in late 2019, known to be a highly transmissible and pathogenic disease, has caused the COVID-19 global pandemic outbreak. Diagnostic devices that help epidemiological public safety measures to reduce undetected cases and isolation of infected patients, in addition to significantly help to control the population's immune response to vaccine, are required. To address the negative issues of clinical research, we developed a Diagnostic on a Chip platform based on a disposable electrochemical biosensor containing laser-induced graphene and a protein (SARS-CoV-2 specific QCoV-8 antigen) for the detection of biomarkers (anti-SARS-COV-2 antibodies). The biosensors were produced by means of the direct laser engraving method using a CO2 laser cutting machine on commercial polyimide sheets. The presence of anti-SARS-CoV-2 antibodies reacts with the antigen and the redox indicator K3[Fe(CN)6] producing characteristic and concentration dependent electrochemical signals, with an estimated analysis processing time of 3 min. The DoC platform coupled to a commercial potentiostat showed average current values for tests performed on reactive and non-reactive clinical samples, reaching 9.53 µA (standard deviation of 0.32) and 7.96 µA (standard deviation of 0. 84), respectively. While the DoC platform coupled to the portable microcontrolled potentiostat exhibited signals with average current values of 9.6757 and 8.1812 µA in serum biofluids of reactive and non-reactive patients respectively for anti-SARS-CoV-2 antibodies. In this way, the platform presents new possibilities for the diagnosis of COVID-19 and is being optimized for measurements in a portable microcontrolled potentiostat to be applied as a rapid and reliable monitoring and mapping tool, with the objective of evaluating the vaccine immune response of the population.