Portable Point-of-care COVID19 Test By University of Illinois Researchers
University of Illinois, Urbana-Champaign researchers have developed a COVID-19 test instrument which could enable point-of-care diagnosis without needing to send samples to a lab, in a new study. They demonstrated a prototype of a rapid COVID-19 molecular test and a portable, simple-to-use instrument for reading the results in 30 minutes with a smartphone.
A professor of bioengineering and the dean of the Grainger College of Engineering at Illinois, Rashid Bashir said, “We could test for COVID-19 at large gatherings, auditoriums, public events, and potentially even at home for self-testing if such a device and test were available. Then, for coordination, the results could be sent back to the appropriate public health.” Along with mechanical science and engineering professor Bill King and electrical and computer engineering professor Brian Cunningham, Bashir co-led the study.
Typical tests for the virus that causes COVID-19, SARS-CoV-2, involves taking a sample from a patient with a long nasopharyngeal swab, and sending it to a lab after putting that swab into a substance called viral transport media. A multistep process of extractin
g, isolating, and multiplying the telltale RNA inside the virus is carried out with the samples in the lab. Cunningham said that specialized equipment, several temperature fluctuation cycles, and trained personnel are required for this RNA multiplication process, called RT-PCR.To analyze the viral transport media, the Illinois team used a simpler process called LAMP, which bypasses the RNA extraction and purification steps, as reported in the Proceedings of the National Academy of Sciences.
The first author of the study, a graduate student Anurup Ganguli said, “LAMP only needs one temperature—65 C, thus it is much easier to control. Additionally, when there are contaminants in the test sample, the LAMP works more robustly than PCR. We can detect the genetic sequence that specifically identifies SARS-CoV-2 by just briefly heating the sample, and break open the virus.”
Making use of synthetic nasal fluid spiked with the virus and then with clinical samples, the researchers compared the LAMP assay with PCR. They documented the sensitivity and specificity of the LAMP test, and they found the results were in agreement with PCR results.
Later, onto a small 3-D-printed microfluidic cartridge that has two input slots for syringes, the researchers incorporated the LAMP assay. Out of the two input slots, one was for the LAMP chemicals, and one for the sample-containing viral transport media. These react within the cartridge once the two are injected.
King said, “To make these cartridges, we use modern, high-speed additive manufacturing, and the entire thing can be quickly scaled up to hundreds of thousands of tests. For commercial applications of microfluidic cartridges, production scale-up is typically the biggest obstacle and using this new approach, we can overcome that obstacle. Modern additive manufacturing can be ramped up very quickly compared with legacy manufacturing technologies as it is elastic and scalable.”
To manufacture the microfluidic cartridges, the team is working with a Chicago-based technology company King co-founded, Fast Radius Inc.
The cartridge can be inserted into a hand-held portable instrument with a smartphone cradle for reading the results, and a heating chamber, which heats the cartridge to 65 degrees Celsius for the duration of the reaction. A positive result will emit fluorescent light in approximately 30 minutes.
Cunningham said, “The phone’s rear-facing camera records a movie of the green fluorescent light being generated while the reader illuminates the liquid compartments with light from blue LEDs.”
The researchers found their results matched those of the standard PCR lab procedure as they demonstrated the portable device with additional clinical samples.
In order to eliminate the need for nasopharyngeal swabs, the researchers are exploring whether the assay would work with saliva samples, and are also collecting more patient data. Bashir said that they are considering the next steps for regulatory approvals.
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Portable Point-of-care COVID19 Test By University of Illinois Researchers
