Most viral test kits rely on labor- and time-intensive laboratory preparation and analysis techniques; for example, tests for the novel coronavirus can take days to detect the virus from nasal swabs. Researchers have demonstrated an inexpensive yet sensitive smartphone-based testing device for viral and bacterial pathogens that takes about 30 minutes to complete and costs roughly $50.
There are a few preparatory steps currently performed outside of the device and the team is working on a cartridge that has all of the reagents needed to be a fully integrated system. Other researchers are using the novel coronavirus genome to create a mobile test for COVID-19 and making an easily manufactured cartridge that would improve testing efforts.
The study began with the goal of detecting a panel of viral and bacterial pathogens in horses, including those that cause severe respiratory illnesses similar to those presented in COVID-19. Horse pathogens used in the study are harmless to humans.
The new testing device, called PathTracker, is comprised of a small cartridge containing testing reagents and a port to insert a nasal extract or blood sample. The whole unit clips to a smartphone. Inside the cartridge, the reagents break open a pathogen’s outer shell to gain access to its RNA. A primer molecule then amplifies the genetic material into many millions of copies in about 10 or 15 minutes. A fluorescent dye stains the copies and glows green when illuminated by blue LED light, which is then detected by the smart-phone’s camera.
The test can be performed rapidly on passengers before getting on a flight, on people going to a theme park, or before events like a conference or concert. Cloud computing via a smartphone application could allow a negative test result to be registered with event organizers or as part of a boarding pass for a flight. Or, a person in quarantine could give themselves daily tests, register the results with a doctor, and then know when it’s safe to rejoin society.