Scientists are developing a new CRISPR-based test that uses a smartphone camera to detect COVID-19

There is not much a smartphone can do these days. However, can it help detect SARS-CoV-2 corona virus? According to a new study, yes, it can. Scientists have designed a new test that can detect the presence of the virus that causes COVID-19 in the nasal passages through a device attached to a standard smartphone.

According to researchers at the Gladstone Institute, the University of California, Berkeley, and the University of California, San Francisco, ongoing research is showing encouraging results and potential for application to a wide variety of viruses.

“Our study shows that the detection part of this test can be done very quickly, which is measured using mass-produced consumer electronics. We do not need fancy laboratory equipment,” said co-senior author of the study. Daniel Fletcher said. , In a statement.

Advantage over current methods

Current COVID-19 tests are based on the conversion of RNA into DNA, followed by amplification using polymerase chain reaction (PCR) technology (making multiple copies of the DNA sequence). What makes this experiment unique is that it uses a one-step response to direct testing of viral RNA, as opposed to a two-step process in traditional PCR tests, ”said the study’s co – senior author. Melanie Ott said. .

The new test uses CRISPR-Cas technology, which detects viral RNA using the enzyme Cas13. Using nasal chylase containing SARS-CoV-2 RNA. “Instead of the CRSPR protein known as CAS9, which detects and purifies DNA, we used CAS13, which purifies RNA,” said Parinas Fosouni, co-author of the study.

An RNA-based probe or reporter attaches to a molecular reaction that produces fluorescence that a camera can detect when split. The sample was added to a device attached to a smartphone. If viral RNA is detected in the sample, case 13 is triggered, which clears the probing molecule. This leads to the emission of fluorescent signals.

Now, the camera of the smartphone, which is basically transformed into a portable microscope, can detect fluorescence and confirm the presence of Kylase COVID-19. The fluorescence detector includes a laser that illuminates and stimulates the fluorescence, and an additional lens that helps in light collection.

Quick detection and results

When the team used patient samples to test the setup, they realized that the samples could be processed faster (or faster turning times) and would give quicker results when viral loads were therapeutically relevant. In one particular case, the authors found that the device accurately detected a series of samples within 5 min. Most importantly, for samples with low viral load, results are obtained within just 30 minutes after detection.

“Recent models of SARS-CoV-2 indicate that regular testing with a faster turnaround time should overcome the current pandemic. With increased testing, we hope to be able to avoid lockdowns and protect the most vulnerable people,” Drs. Ott. Dr. Ott, Dr. Fletcher and Nobel Laureate Dr. The new technology is the result of a collaboration with Jennifer Dowdna.

Portable with scope for wide application

In addition to faster testing times, the biggest advantage of the new test is the portability that relies solely on a smartphone, avoiding large specialized devices. This will enable availability for home or point of care use.

“Simple chemistry paired with a smartphone camera reduces detection time and does not require complex lab equipment. This allows the test to provide quantitative measurements rather than a positive or negative result,” Drs.

In addition, the testing methodology can be adapted to detect other respiratory viruses such as influenza and deadly RNA viruses, such as HIV, by making small changes to suit different sample collection methods.

Highlighting its potential, Dr. Ott said, “We need to change the extraction methods because we’ll be dealing with blood instead of nasal kylase, but we’ve developed the fluorescent detection part which is really helpful.”