Economical, portable detector identifies pathogens in minutes

Most viral test kits are based on laboratory analysis and preparation techniques that require a lot of work and time; For example, tests for the new coronavirus can take days to detect the virus from nasal swabs. Now, researchers have demonstrated an inexpensive but sensitive smartphone-based test device for viral and bacterial pathogens that takes about 30 minutes to complete. The approximately $ 50 smartphone accessory could reduce pressure on testing labs during a pandemic like COVID-19.

The results of the new multi-agency study, led by Professor of Electrical and Computer Engineering Brian Cunningham of the University of Illinois at Urbana-Champaign and Professor of Bioengineering Rashid Bashir, are reported in the journal. Lab on a Chip.

“The challenges associated with rapid pathogen testing contribute to great uncertainty about which individuals are in quarantine and a host of other health and economic problems,” said Cunningham.

The study began with the goal of detecting a panel of viral and bacterial pathogens in horses, including those that cause serious respiratory illnesses similar to those presented at COVID-19, the researchers said.

“Horse pathogens can lead to devastating diseases in animal populations, of course, but one of the reasons we work with them has to do with safety. The horse pathogens in our study are harmless to humans. “Cunningham said.

The new test device is made up of a small cartridge containing test reagents and a port to insert a nasal extract or blood sample, the researchers said. The entire unit connects to a smartphone.

Inside the cartridge, the reagents break the outer jacket of a pathogen to gain access to its RNA. The researchers said that a primer molecule amplifies the genetic material by many millions of copies in about 10 to 15 minutes. A fluorescent tint stains the prints and glows green when illuminated by a blue LED light, which is then detected by the smartphone’s camera.

“This test can be done quickly on passengers before taking a flight, on people going to a theme park, or before events like a conference or concert,” said Cunningham. “Cloud computing through a smartphone app could allow a negative test result to be recorded with event organizers or as part of a boarding pass for a flight. Or, a quarantined person could be daily tests, record the results with a doctor and then know when it is safe to go out and join society. “

There are currently some preparatory steps performed outside of the device, and the team is working on a cartridge that has all the reagents necessary to be a fully integrated system. Other U. of I. researchers are using the new coronavirus genome to create a mobile test for COVID-19, and are building an easily manufactured cartridge that Cunningham said would improve testing efforts.