Scientists are developing a smartphone app that can detect COVID-19 in saliva in about 10 minutes.

The technology pairs a phone with a small microscope that analyzes a saliva sample for evidence of the virus. 

Designed by the University of Arizona, the team’s goal is to combine the speed of an antigen test with the accuracy of a polymerase chain reaction, or PCR, test.

The technology was originally developed as an inexpensive method to identify norovirus, but was altered in light of the ongoing pandemic.

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Scientists at the University of Arizona have developed a smartphone app that works with a microscope to test saliva samples for COVID-19. The process takes only about 10 to 15 minutes and the components cost about $45

The process, reported in the journal Nature Protocols, consists of a microscope and a wax-coated sheet, is called microfluidic paper, which guides the sample through certain channels.  

After putting a saliva sample on the paper, a patient introduces antibodies with fluorescent beads. 

If enough coronavirus particles are present, antibodies will attach to each one.

‘Under a microscope, the pathogen particles show up as little clumps of fluorescent beads, which the user can then count,’ the researchers explained.  

After putting a saliva sample on a sheet of microfluidic paper, the user introduces antibodies with fluorescent beads. If enough coronavirus particles are present, the antibodies will attach to each one. The virus particles will look like little clumps of fluorescent beads, which the user can then count

According to the researchers, the whole process – adding beads to the sample, soaking the paper in the sample, then taking a smartphone photo of it under a microscope and counting the beads – takes 10 to 15 minutes.   

Katie Sosnowski, a doctoral student in the university’s department of biomedical engineering, said it was ‘cool’ to be working on a test that offered ‘fast results that are also accurate.’ 

‘I have a couple of friends who had COVID-19 that were super frustrated, because their PCR results were taking six or seven days or they were getting false negatives from rapid antigen tests,’ she said.

‘But when they got the final PCR tests, they found out they had been sick, like they’d suspected.’  

Researchers also developed a 3D-printed housing for the microscope attachment and microfluidic paper chip. They also developed  a method called ‘adaptive thresholding,’ which uses AI to account for differences in the kind of phone used, the quality of the paper and other factors

The team, led by biomedical engineering professor Jeong-Yeol Yoon, originally reported on their work in a 2019 paper in the journal ACS Omega.

At that time, they were thinking of fast and easy ways to test for norovirus, the highly contagious virus that often breaks out on cruise ships, but they believe it could be adapted to identify any number of viral infections.

For the coronavirus kit the team added a 3D-printed housing for the microscope attachment and microfluidic paper chip. 

A method called ‘adaptive thresholding’ was also introduced that uses artificial intelligence to set the danger threshold and account for differences in the kind of phone used, the quality of the paper and other factors. 

‘We’ve outlined it so that other scientists can basically repeat what we did and create a norovirus-detecting device,’ said Lane Breshears, a doctoral student studying under Yoon.

‘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.’

Most methods for detecting COVID-19 or other pathogens are time-consuming, expensive and require medical expertise. 

The total cost of the components for the U of Arizona test is about $45 and it’s easy enough that a layperson could do it after watching a brief instructional video.

The technology still has a way to go before heading to market, but researchers hope to get permission to test samples from students who are already getting tested for COVID-19 on campus through other established methods.

Ultimately, they envision distributing the device around campus so a RA could test students in a dorm.

‘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 University of Arizona president Robert C. Robbins.

‘This promising technology could allow us to provide fast, accurate, affordable tests to the campus community frequently and easily.’

Yoon’s team also conceived of adapting the technology so it wouldn’t even need a microscope, just an app and a microfludic chip with a special QR code.

It would leave slightly more room for error but would require no training and could even be self-administered.

Since the arrival of the novel coronavirus, scientists around the world have been working to develop faster, cheaper and more convenient testing methods.

Current testing requires a swab of the nose and back of the throat, usually in a clinic, which can be time-consuming and unpleasant.

In May 2020, researchers at the University of Pittsburgh announced they were working on an app that uses artificial intelligence to analyze the sounds coming from someone’s airway and determine if they matched those of a COVID-19 patient.

Developers are working on smartphone apps that can accurately test for COVID-19 while still being inexpensive, convenient and painless. If successful, it would rapidly increase testing and enable people to avoid congregating at clinics or hospitals 

Users would need to use an adapter as a mouthpiece so that the phone’s microphone and speaker can record and transmit acoustic signals from their airway.

The goal is to create a cheap and simple system that allows people to be tested for COVID-19 from their own home ‘and quickly and effectively identify viral disease carriers,’ said lead researcher Wei Gao.

‘We hope this work will also help identify negative cases caused by other diseases with similar symptoms, and therefore, help eliminate unnecessary hospital visits during this pandemic.’

A separate team from Switzerland is attempting to develop a similar system using coughs.

‘It seems clear that a high proportion [of coronavirus patients] have this type of dry cough that’s different from the flu or allergies,’ Tomas Teijeiro, lead researcher for the Coughvid project, told the Wall Street Journal.

The makers of another app, PocDoc, say it can be combined with your phone’s camera to analyze a blood sample and provide rapid results for a COVID-19 antibody test.

A user pricks their finger, puts a drop of blood on the test slide and then takes a photo. The software is designed to detect small color changes when COVID antibodies are present and provide results within five minutes.

‘COVID-19 has accelerated the requirement for innovative health tech of all kinds,’ said PocDoc CEO Steve Roest. 

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