COVID-19 rapid test enables point of care diagnosis

Reviewed by Emily Henderson, B.Sc.September 1, 2020

As COVID-19 continues to expand, bottlenecks between supplies and lab personnel are creating long wait times for results in some regions.

A new study at the University of Illinois at Urbana-Champaign demonstrated a prototype of the COVID-19 rapid molecular test and an easy-to-use portable device for reading results in 30 minutes on a smartphone. Care-of-care diagnostics without the need to send samples to the lab.

If such devices and tests were available, you could test the COVID-19 for self-tests at public events, auditoriums, large gatherings, and even at home. The results are sent back to the appropriate public health system for adjustment.“

Rashid Bashir, University of Illinois at Urbana-Champaign, Professor at the Grainer College of Engineering, Bioengineering and Dean

Bashir collaborated with Brian Cunningham, a professor of electrical and computer engineering, and Birking, a professor of mechanical science and engineering.

A typical test for SARS-CoV-2, the virus that causes COVID-19, involves taking a sample from a patient using a long nasopharyngeal swab and placing the swab in a substance called viral transport medium, a multistep process. Sent to the lab for How to extract, isolate and propagate the telltale RNA inside the virus.

According to Cunningham, this RNA-proliferation process, called RT-PCR, requires several temperature fluctuation cycles, specialized equipment, and trained personnel.

As reported in Minutes of the National Academy of SciencesA team in Illinois used a simpler process to analyze a viral transport medium called LAMP. This bypasses the RNA extraction and purification steps.

“LAMP requires only one temperature (65 C), which makes it much easier to control,” said graduate student Anurup Ganguli, the lead author of the study. “LAMP also works more powerfully than PCR, especially when test samples are contaminated. Gene sequences that specifically heat up the sample, disintegrate the virus, and specifically identify SARS-CoV-2. Can be detected.”

The researchers compared the LAMP assay with PCR. We used synthetic spiked nasal fluid first, and then clinical samples. They found that the results were consistent with the PCR results and documented the sensitivity and specificity of the LAMP test.

Next, the researchers incorporated the LAMP assay into one 3D-printed microfluidic cartridge with two input slots for syringes. One for the viral transport medium containing the sample and one for the LAMP chemical. When the two are injected, they react in the cartridge.

“We use the latest high-speed additive manufacturing methods to manufacture these cartridges, and we can quickly scale up to hundreds of thousands of tests,” King said.

“Increased production is usually the biggest obstacle to commercial applications for microfluidic cartridges, and this new approach can be used to overcome that obstacle. Modern additive manufacturing is elastic, scalable, and legacy. It can be launched very quickly compared to manufacturing technology.”

The team works with King’s co-founded Chicago-based technology company Fast Radius Inc. to manufacture microfluidic cartridges.

The cartridge can be inserted into a handheld portable device equipped with a heating chamber that heats the cartridge to 65 degrees Celsius during the reaction and a smartphone cradle to read the results. In about 30 minutes, a positive result will give off a fluorescent light.

“The reader illuminates the liquid compartment with light from a blue LED, but the rear camera of the phone records a video of the green fluorescent light being produced,” Cunningham said.

Watch YouTube for cartridges, handheld devices, and process videos.

The researchers demonstrated a portable device with an additional clinical sample and found that the results were consistent with those of standard PCR lab procedures.

Researchers are investigating whether this assay works with saliva samples to eliminate the need for nasopharyngeal swabs, and when considering the next steps for regulatory approval, more patients It is supposed to collect data.