Sunday, June 20

A new fast and reliable test that offers results in four minutes with a Spanish seal


RAPID, a low-cost covid-19 diagnostic test

RAPID, a low-cost covid-19 diagnostic test
Penn Medicine

A rapid and low-cost diagnostic test for covid-19 developed by Penn Medicine (United States) provides results in four minutes with an accuracy of 90 percent.

An article published this week in the journal ‘Matter’ details this quick and inexpensive diagnostic test, called ‘RAPID 1.0’. Compared to existing methods for detecting covid-19, the test is cheap and highly scalable, allowing the production of millions of units per week.

Despite the urgency of the pandemic, most methods available for testing for covid-19 use PCR to detect SARS-CoV-2. Although effective, the technique requires a large lab space and skilled workers to use it. These tests are also expensive, run the risk of cross contamination, and can take hours or days to produce results.

This new test has been developed by a team led by Dr. César de la Fuente, Galician biotechnologist and winner of Scientific Research from the Princess of Girona Foundation, to detect the virus quickly and accurately and, at the same time, cheaply enough enough to be widely accessible. An electrode printed with a screen printer (thousands of them can be printed in one day at very low cost) can detect the virus in nasal swab or saliva samples. The results can be read on a computer or on a ‘smartphone’.

“Before the pandemic, our lab was working on diagnosing bacterial infections. But then covid-19 came along. We felt a responsibility to use our experience to help, and the diagnostic space was ripe for improvements. We are very concerned about inequalities. health services that occurred during the pandemic, for example, in access to testing and vaccine deployment. We believe that low-cost diagnostic tests like this could help bridge some of those differences, “explains De la Fuente.

The ‘RAPID’ technology uses electrochemical impedance spectroscopy (EIS), which transforms the binding event between the SARS-CoV-2 viral spike protein and its receptor in the human body, the ACE2 protein (which provides the point input for the coronavirus to latch onto and infect human cells), into an electrical signal that doctors and technicians can detect. That sign allows the test to discriminate between infected and healthy human samples. The signal can be read through a desktop instrument or a smartphone.

The team evaluated the performance of their test using COVID-19 positive and negative clinical samples from the Hospital of the University of Pennsylvania, including samples of the British variant. In blind tests, they analyzed 139 nasal swab samples: 109 of which were positive for COVID-19 and 30 negative for COVID-19, as determined by PCR. The team also analyzed 50 saliva samples from the patients. For nasal swab samples, ‘RAPID’ was 87.1 percent accurate. For saliva samples, it was 90 percent.

‘RAPID’ provides results in four minutes, which is faster than most currently available methods for diagnosing COVID-19. For example, serological tests can take 15-20 minutes, and are 60-70 percent accurate.

What’s more, is capable of detecting the COVID-19 virus in extremely low concentrations (1.16 PFU mL), which corresponds to a viral load that correlates with the initial stages, around two or three days after the onset of symptoms. This is beneficial in detecting individuals in the early stages of infection, allowing for quick attention and the potential decrease of further viral spread.

Most importantly, the technology is affordable and scalable. The production of each test, which can be done at room temperature, costs $ 4.67 (3.86 euros). In addition, the electrodes used in the test can be rapidly mass produced using commercially available screenprints to print the circuit board (called eChip). A unit the size of a laboratory is capable of producing 35,000 electrodes per day (about 1.05 million per month).

The team also built an electrode for ‘RAPID’ made up of filter paper, which is a cheaper and more accessible material. Under the name ePAD, the researchers demonstrated the applicability of ePAD for ‘RAPID’ in a portable method, connected to a smart device, which can enable increased scale and on-demand testing capabilities at the point of care. “Dispose of low-cost tests that are quick and easy to read It extends the tests not only to people who can afford it, but to remote or disadvantaged areas “, Rivets De la Fuente.


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