Desenvolvimento de um dispositivo eletroquimiluminescente de baixo custo para detecção do SARS-CoV-2 em saliva

Abstract

This work is a response to the COVID-19 pandemic, in which a new method for detecting the SARS-CoV-2 virus in saliva based on genome-genetic assay performed at room temperature is proposed. The method allows the detection of viral RNA quickly, without the need for steps of transcription and amplification of the genetic material, the signal being obtained using the electrochemiluminescence (ECL) technique. For this, a disposable platform was developed allowing to work with 10 samples simultaneously, reducing the cost of inputs and reagents. Two nucleotide sequences of the virus nucleocapsid gene were studied, named sequence 1A and sequence 2A. The viral RNA calibration curves were evaluated for two sequences individually, and these were linear in the range of 5.0 fmol L-1 to 5.0 nmol L-1, with a linear correlation coefficient of 0.999 for sequence 1A and 0.975 for sequence 2A. Cohorts of positive and negative patient samples were evaluated as a comparative method. The analysis of the Receiver Operating Characteristic (ROC) curve showed that the method achieved excellent sensitivity and specificity for the 1A sequence, which was more sensitive than the 2A sequence. Also, the test was performed with the presence of the two sequences simultaneously and evaluated in two different cohorts of patients. The proposed method showed an excellent discriminatory ability of individuals with COVID-19, with a sensitivity and specificity of 92%. To assess the accuracy of the method, more than 200 samples were tested with RT-PCR or rapid antigen test results.