Researchers develop smartphone-based COVID-19 test that provides results in about 10 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 in about 10 minutes.

The UArizona research team, led by biomedical engineering professor Jeong-Yeol Yoon, aims to combine the speed of existing nasal swab antigen tests with the high precision of nasal swab PCR tests, or polymerase chain reaction. The researchers are adapting an inexpensive method 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 swish-gargle saline test developed by Michael Worobey, head of UArizona’s Department of Ecology and Evolutionary Biology and associate director of the University of Arizona’s BIO5 Institute.

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

“We designed it so that other scientists can 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 adapt it to something else, as we adapted it for COVID-19, 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 sciences and comparative biomedical and chemistry and biochemistry – is working with a large group of undergraduate and graduate students to develop the COVID-19 based detection method on smartphone.

“I have some friends with COVID-19 who were super frustrated because their PCR results were taking six or seven days or they were getting false negatives from rapid antigen tests. But when they did the final PCR tests, they found out they were sick, as they suspected, “said Katie Sosnowski, a doctoral student in biomedical engineering who works in Yoon’s lab. “It is really cool to work on a detection platform that can get results that are fast and also accurate.”

Cheaper and simpler detection

Traditional methods of detecting norovirus or other pathogens are often expensive, involve a large set of laboratory equipment, or require scientific knowledge. 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 liquid sample to flow through specific channels. It is smaller and cheaper than other tests, with components costing around $ 45.

The basis of technology, described in a 2019 article published in the magazine ACS Omega, is relatively simple. Users introduce antibodies with fluorescent spheres into a sample of potentially contaminated water. If sufficient particles of the pathogen are present in the sample, several antibodies bind to each particle of the pathogen. Under a microscope, the particles of the pathogen appear as small clusters of fluorescent beads, which the user can then count. The process – adding granules to the sample, dipping a piece of paper into the sample and then taking a picture of the smartphone under a microscope and counting the bills – takes about 10 to 15 minutes. It is so simple that Yoon says that a non-scientist can learn how to do it by watching a short video.

The version of the technology described in Nature Protocols the paper makes further improvements, such as the creation of a 3D printed box for the microscope accessory and the microfluidic paper chip. The article also presents a method called adaptive thresholding. Previously, researchers set a fixed value for the amount of pathogen that constituted a hazard, which limited levels of accuracy. The new version uses artificial intelligence to define the danger limit 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 partner with test facilities at the University of Arizona to adjust their method as they adapt it for COVID-19 detection. Pending approval from the university’s institutional review board, students who are already being tested on campus using other methods will have the option of providing written consent for their sample to be tested using the smartphone-based test device also. Ultimately, the researchers plan to distribute the device to campus centers so that the average person – like an assistant resident in a dormitory – could test saliva samples from groups of people.

“Adapting a method developed to detect norovirus – another highly contagious pathogen – is an excellent example of how our researchers are dealing with the pandemic,” said University of Arizona President Robert C. Robbins. “This promising technology can enable us to provide rapid, accurate and affordable testing to the campus community frequently and easily. We hope to make it a regular part of our ‘Test, Track, Treat’ strategy and have a broader mitigation impact. spread of the disease. “

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

“Unlike the fluorescent microscope technique, where you put the chip in the right position, you just take a picture of the chip,” said Pat Akarapipad, a student in biomedical engineering. “No matter what angle or distance the photo is taken from, the smartphone app can use AI and the QR code to account for variations and perform calculations accordingly.”

The method does not require training, so if it is perfected, it can allow students to collect microfluidic chips from a campus and test their own samples. The team is also working with other members of the university’s COVID-19 test group, including Deepta Bhattacharya, an associate professor in the Department of Immunobiology.