Yoon Leads Team Developing Smartphone-Based COVID-19 Test

BME professor Jeong-Yeol Yoon is leading a University of Arizona research team developing a COVID-19 testing method that uses a smartphone microscope to analyze saliva samples and deliver results in about 10 minutes. The team aims to combine the speed of existing nasal swab antigen tests with the high accuracy of nasal swab PCR, or polymerase chain reaction, tests. The researchers are adapting an inexpensive method that they originally created to detect norovirus – the microbe famous for spreading on cruise ships – using a smartphone microscope.

They plan to use the method in conjunction with a saline swish-gargle test developed by Michael Worobey, associate director of the UA BIO5 Institute. The team's latest research using water samples – done in collaboration with Kelly A. Reynolds, chair of the Department of Community, Environment and Policy in the UA Mel and Enid Zuckerman College of Public Health – was published in Nature Protocols.

"We've outlined it so that other scientists can basically repeat what we did and create a norovirus-detecting device," said Lane Breshears, a BME doctoral student in Yoon's lab. "Our goal is that if you want to adapt it for something else, like we've adapted it for COVID-19, that you have all the ingredients you need to basically make your own device."

Traditional methods for detection of norovirus or other pathogens are often expensive, involve a large suite of laboratory equipment or require scientific expertise. The smartphone-based norovirus test developed at UA consists of a smartphone, a simple microscope and a piece of microfluidic paper – a wax-coated paper that guides the liquid sample to flow through specific channels. It is smaller and cheaper than other tests, with the components costing about $45.

The basis of the technology, described in a 2019 paper published in the journal ACS Omega, is relatively simple. Users introduce antibodies with fluorescent beads to a potentially contaminated water sample. If enough particles of the pathogen are present in the sample, several antibodies attach to each pathogen particle. Under a microscope, the pathogen particles show up as little clumps of fluorescent beads, which the user can then count. The process – adding beads to the sample, soaking a piece of paper in the sample, then taking a smartphone photograph of it under a microscope and counting the beads – takes about 10 to 15 minutes. It's so simple that Yoon says a nonscientist could learn how to do it by watching a brief video.

"Adapting a method designed to detect the norovirus – another highly contagious pathogen – is an outstanding example of our researchers pivoting in the face of the pandemic," said UA President Robert C. Robbins. "This promising technology could allow us to provide fast, accurate, affordable tests to the campus community frequently and easily. We hope to make it a regular part of our 'Test, Trace, Treat' strategy, and that it will have a broader impact in mitigating the spread of the disease."

For more information, watch news channel KOLD's report on the test.