Development of colorimetric detection using a molecular biology and nanotechnology platform for the rapid diagnosis of COVID-19

Abstract

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is the agent of Coronavirus Disease 2019 (COVID-19). The transmission occurs through contact with contaminated surfaces, aerosol inhalation or through spills and secretions. Between the 5th and 14th day: fever, dry cough, tiredness, sore throat, headache, diarrhea, loss of smell and / or taste may appear as symptons. In severe cases: shortness of breath, chest pain or pressure, speech loss and movement disability are mostly associated with comorbidities. The disease reached pandemic status within a large number of deaths. The main methodologies for diagnosis are the fast test (sensitivity 70%) and RT-PCR (sensitivity 99%, which has a higher cost). Diagnosing and tracking patients is important to decrease the spread and allow a safe return of economic, educational, leisure and sports activities. The objective is to develop a sensitive, specific, simplified and accessible test by colorimetric detection of SarsCov-2. Nasopharynx and saliva samples from patients with COVID-19 are going to be collected. In microtube 1, the RNA will be extracted. In microtube 2, reagents will be added for cDNA and RT-PCR synthesis plus thiolated primers (regions: Spike, RNApol and Nucleocapsid), after it, the samples will be subjected to thermal cycling in the dry bath. Afterwards reagent 3 (reading) will be added, which contains gold nanoparticles. The color change from red to blue will be observed when the genetic material is detected by two principles: RT-PCR (exponential increase of the target genes) and Nanotechnology (thiolated primers at the ends of the amplicon will react with nanoparticles occurring the colorimetric reaction). The results of this project will be a low-cost qualitative and quantitative solution with an early and assertative diagnosis of symptomatic patients and identification of asymptomatic patients. Contributing to the planning of public policies in concearn to the treatment and mitigation of contagion. (AU)