Researchers develop smartphone-based COVID-19 test that delivers results within ten minutes

Researchers at the University of Arizona are developing a COVID-19 test method that uses a smartphone microscope to analyze saliva samples and deliver results within ten minutes.

The UArizona research team, led by Professor Jeong-Yeol Yoon in biomedical engineering, aims to combine the speed of existing antigen tests for nasal swabs with the high accuracy of PCR, or polymerase chain reaction, tests. The researchers are adapting an inexpensive method they originally created to detect norovirus – the microbe known to spread on cruise ships – using a smartphone microscope.

They plan to use the method in conjunction with a salt-gargle test developed by Michael Worobey, head of the UArizona Department of Ecology and Evolutionary Biology and co-director of the BIO5 Institute of the University of Arizona.

The team’s latest research using water samples – conducted in collaboration with Kelly A. Reynolds, Chair of the Department of Community, Environment and Policy at the UArizona Mel and Enid Zuckerman College of Public Health – is published today in Nature protocols.

“We set it out so that other scientists could basically repeat what we did and create a norovirus detection device,” said Lane Breshears, a doctoral student in biomedical engineering at Yoon’s laboratory. “Our goal is that if you want to customize it for something else, like we customized it for COVID-19, that you have all the ingredients you need to basically make your own device.”

Yoon – a member of the BIO5 Institute, who is also a professor of biosystems engineering, animal and comparative biomedical sciences, and chemistry and biochemistry – is working with a large group of undergraduate and graduate students to create the smartphone-based COVID To develop -19 detection method.

“I had some friends who had COVID-19 who were very frustrated because their PCR results took six or seven days or if they got false negative results from fast antigen tests. But when they got the final PCR tests “they found out they were sick, as they suspected,” said Katie Sosnowski, a doctoral student in biomedical engineering working in Yoon’s lab. “It’s very cool to be working on a tracking platform that can provide quick results. get what is also accurate. “

Cheaper, easier detection

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

The basis of the technology, described in a 2019 article published in the magazine ACS Omega, is relatively simple. Users bring antibodies with fluorescent beads into a potentially contaminated water sample. If there are enough particles of the pathogen in the sample, attach several antibodies to each pathogen particle. Under a microscope, the pathogen particles display a few pulse light 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 photo of it under a microscope and counting the beads – takes about 10 to 15 minutes. It’s so simple that Yoon says a scientist can learn how to do it by watching a short video.

The version of the technology used in the Nature protocols paper makes further improvements, such as the creation of a 3-D-printed housing for the microscope attachment and the microfluidic paper. The paper also introduces a method called adaptive thresholding. Previously, researchers have established a fixed value for the amount of pathogen that is a hazard, limiting the precision levels. The new version uses artificial intelligence to set the danger threshold and take into account environmental differences, such as the type of smartphone and the quality of the paper.

Impact on campus

The researchers plan to work with test facilities at the University of Arizona to refine their method while adapting it for COVID-19 detection. Pending approval by the university’s institutional review board, students who have already been tested on other campuses will have the option of giving written permission that their sample can also be performed by the smartphone-based testing device. Ultimately, the researchers aim to distribute the device to campus hubs so that the average person – like an assistant in a residence – could test saliva samples from groups of people.

“The adaptation of a method designed to detect the norovirus – another highly contagious pathogen – is an excellent example of our researchers facing the pandemic,” said Robert C. Robbins, president of the University of Arizona, said. “This promising technology can enable us to deliver fast, accurate and affordable tests to the campus community regularly and easily. We hope to make this a regular part of our ‘Test, Detect, Treat’ strategy and that it will have a broader impact. to mitigate the spread of the disease. ‘

Yoon and his team are also working on another idea, based on an article in 2018 in which they published Chemistry – A European Journal, which is even simpler, but leaves slightly more room for error. It involves the same technology, but instead of a smartphone microscope and specially designed casing, users will only need to download a smartphone app and use a microfluidic chip with a QR code.

“Unlike the fluorescent microscope technique, where you bring the chip into the correct position, you only take a snapshot of the chip,” said Pat Akarapipad, a biomedical engineering student. “No matter the angle or distance from which the photo is taken, the smartphone app can use AI and the QR code to offset deviations and perform calculations accordingly.”

The method requires no training, so if it is perfect, students may be able to pick up microfluidic chips from a campus room and test their own samples. The team also works with other members of the university’s COVID-19 test group, including Deepta Bhattacharya, associate professor in the Department of Immunobiology.