A team of researchers in the US has developed an assay that can detect the presence of Covid-19 virus in a nasal swab using a device attached to an smartphone.
Although more research is needed before such a test can be rolled out, the results are promising and ultimately may be applicable to screening more broadly for other viruses, the study authors wrote in a paper published in the journal Cell.
“Our study shows that we can do the detection part of this assay very quickly, making the measurement with mass-produced consumer electronics,” said Daniel Fletcher, a bioengineer at the University of California in Berkeley.
“We don’t need fancy laboratory equipment”.
In the current study, the nasal swabs were spiked with SARS-CoV-2 RNA.
The investigators are currently working on a solution that would induce a single-step reaction in which the RNA is released from the virus without the need for purification.
Because it doesn’t require amplification, the assay is able to quantify the amount of virus in the sample.
“It’s super exciting to have this quantitative aspect in the assay. PCR is the gold standard, but you have to go through so many steps,” said co-senior author Melanie Ott, a virologist at Gladstone Institutes and the University of California, San Francisco.
“There are huge opportunities here for pathogens and for biology in general to make RNA quantification more precise”.
The fluorescence detector consists of a laser to produce illumination and excite the fluorescence and an added lens to help collect light.
The smartphone is placed on top of it.
“One takeaway is that the phone camera is 10 times better than the plate reader in the lab,” Ott said.
Fletcher and Ott would like to have this type of test be part of a broader system that could be used at home to screen not only for SARS-CoV-2 but other viruses like those that cause colds and flu.
More immediately, the researchers hope to develop a testing device using this technology that could be rolled out to pharmacies and drop-in clinics.
The team said they would like to get the cost of testing cartridges down to about $10.