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.
UArizona’s research team, led by biochemical engineering professor Jeong-Yeol Yoon, aims to combine the speed of existing nasal swab antigen tests with high-precision PCR nasal swab, or reabsorption polymerase chain. The researchers are modifying a cheap method they originally devised to detect norovirus – the microbiome famous for its spread on cruise ships – using a smartphone microscope.
They plan to use the method in conjunction with a saline-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 uses water samples – carried out in collaboration with Kelly A. Reynolds, chair of the Department of Community, Environment and Policy at UArizona Mel and Enid College of Public Health Zuckerman – published today in Nature Protocols.
We’ve defined it so that other scientists can replicate what we did and create a norovirus detection engine. Our goal is that if you want to change for something else, as we have adapted for COVID-19, you have the ingredients you need to make your own device basic. “
Lane Breshears, Biomedical Engineering Doctoral Student
Yoon – a member of the BIO5 Institute who is also a professor of biosystems engineering, animal and comparative biochemical sciences, and chemistry and biochemistry – works with a large group of undergraduate and graduate students to develop a smartphone-based COVID-19 detection method.
“I have a couple of friends who had COVID-19 which was very difficult, because their PCR results took six or seven days or they were getting a false negative from rapid antigen tests. But when they got the tests Final PCR, they found out they had been sick, as they were under suspicion, “said Katie Sosnowski, a biochemical engineering doctoral student working in the Yoon laboratory. “It’s incredibly attractive to work on a discovery platform that can get fast results that are also accurate.”
Cheaper, simpler proof
Traditional methods for detecting norovirus or other pathogens are often expensive, involve a large array of laboratory equipment or require scientific knowledge. The smartphone-based norovirus test developed at UArizona includes a smartphone, a simple microscope and a piece of microfluidic paper – a wax-coated paper that directs the melt sample to flow through specific channels. It’s smaller and cheaper than other tests, with parts costing around $ 45.
The basis of the technology, outlined in a 2019 paper published in the journal ACS Omega, relatively simple. Consumers attach antibodies with fluorescent beads to a potentially contaminated water sample. If sufficient grains of the pathogen are present in the sample, several antibodies bind to each pathogen grain. Under a microscope, the pathogen particles reveal as few lumps of fluorescent beads, which the user can then count. The process – adding beads to the sample, dipping 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 an inexperienced person could learn how to do it by watching a short video.
The version of the technology described in the Nature Protocols paper makes further improvements, such as creating a 3D printed housing for the microscope connection and a microfluidic paper chip. The paper also introduces a method called variable threshold. Previously, researchers set a fixed value for the amount of pathogen at risk, which limited levels of accuracy. The new version uses artificial intelligence to set the risk threshold and account for environmental differences, such as smartphone type and paper quality.
Impact on the habitat
The researchers plan to partner with test facilities at the University of Arizona to refine their approach while adapting it for COVID-19 detection. Pending approval from the review board of the university institute, students already undergoing campus testing will have the option of obtaining written permission to run their sample through the telephone-based test device. smart too. Eventually, the researchers plan to circulate the device to campus hubs so that the average person – such as a dorm resident – can get saliva samples from groups of people.
“Modifying a method designed to detect the norovirus – another infectious pathogen – is a unique example of our researchers pivoting against the pandemic,” said the President of the University of Arizona, Robert C. Robbins. “This promising technology could enable us to provide fast, accurate, affordable testing to the campus community frequently and easily. We hope to make it a consistent part of our ‘Test, Trace, Treat’ strategy, and to have a wider impact in mitigating the spread of the disease. “
Yoon and his team are also working on another idea, based on a 2018 paper they published there Chemistry – European Journal, which is even simpler but leaves a little more room for error. It incorporates the same technology, but instead of a smartphone microscope and a specially designed circuit, users would only have to download a smartphone app and use a microfluidic chip with a QR code.
“Unlike the fluorescent microscope method, where you get the chip into the correct position, you only take a picture of the chip,” said biomedical engineering master student Pat Akarapipad. “Regardless of the angle or distance from which the photo was taken, the smartphone app can use the AI and the QR code to report differences and run calculations accordingly.”
The method does not require any training, so if done perfectly, it could allow students to pick up microfluidic slips from a campus site and try out 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.
Source:
University of Arizona College of Engineering
Magazine Reference:
Chung, S., et al. (2021) Norovirus detection in water samples at the rate of single virus copies per microliter using a smartphone-based fluorescent microscope. Nature Protocols. doi.org/10.1038/s41596-020-00460-7.