Novel rapid test detects SARS-CoV-2 in saliva and indicates viral load
October 20, 2021
Agência FAPESP – Researchers at the Federal University of São Carlos (UFSCar) in Brazil have patented a novel test to detect SARS-CoV-2 in saliva. The device combines accuracy equivalent to RT-PCR, low cost, and the ability to analyze several samples at the same time. In addition to detecting the presence of the virus, it also indicates an infected individual’s viral load.
The technology used to detect the virus involves an electrochemiluminescence marker, which emits light when stimulated by an electrochemical reaction. Thus, a reaction triggered in the presence of genetic material from the pathogen produces red light, indicating a positive result for COVID-19. The intensity of the red light is proportional to the viral load in the sample. Its absence is a sign that the virus has not been detected and the person is not infected.
Another innovation is the possibility of connecting the device to a smartphone to complete the testing process without the need for help from a trained professional. The project was supported by FAPESP, the Ministry of Education’s Coordination for the Improvement of Higher Education Personnel (CAPES), and the National Council for Scientific and Technological Development (CNPq), also a federal government agency.
“The test has the advantages of being portable, analyzing up to 20 samples concurrently, and connecting to a smartphone. Sensitivity and accuracy are the same as for RT-PCR testing,” Ronaldo Censi Faria, a researcher at UFSCar’s Center for Exact Sciences and Technology (CCET) and principal investigator for the project, told Agência FAPESP.
This is the third test for detecting the novel coronavirus developed and patented by UFSCar’s Bioanalytics and Electroanalytics Laboratory (LaBiE). The other two also achieve a high level of sensitivity and, if produced on an industrial scale by partner companies, could enable mass testing of the Brazilian population, removing one of the bottlenecks to control the COVID-19 pandemic in the country (more at: agencia.fapesp.br/36279).
The first technology developed by the group involves an electrochemical sensor that analyzes the amount of viral spike protein in a saliva sample. The result can be accessed in a matter of minutes via a smartphone app.
The second test model developed at LaBiE detects viral RNA in saliva. Unlike the most recent device, it is based on an adaptation of ELISA (enzyme-linked immunosorbent assay), the platform widely used by clinical laboratories throughout Brazil.
Faria says talks with partner companies to commercialize and mass-produce the first two tests are at an advanced stage. “The more low-cost tests capable of accurately detecting the virus we have, the better. Each model suits a different situation, from clinical analysis labs to individuals self-testing to communities in remote locations,” he explains.
A curiosity of the latest device is that it was originally designed for the diagnosis of sepsis, a systemic inflammatory disorder triggered by bacteria and a leading cause of death in intensive care units (ICUs).
The project resulted from the PhD research of Taise Helena Oliveira Leite, supervised by Faria. “The research project and development of the test had already begun when the pandemic started, and we realized the model could be adapted for diagnosis of COVID-19. We quickly re-engineered the device, which originally detected the DNA and quantity of bacteria that cause sepsis, so that it could detect RNA from SARS-CoV-2 and indicate viral load. This shows how research must be constant, especially when a rapid response to an emergency is required,” Faria says.
An application to patent the new technology has just been filed with INPI, Brazil’s patent and trademark office, by Faria, Leite and Tássia Regina de Oliveira (a postdoc at LaBiE), with several collaborators: Henrique Pott Junior (UFSCar), Ester Sabino (University of São Paulo), Fabio Eudes Leal and Erika Regina Manuli (Municipal University of São Caetano do Sul), and Matias Eliseo Melendez (Cloning Solutions). Commercialization now depends on companies interested in licensing the platform and using it to mass-produce the device.
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