Researchers from the University of Illinois, Urbana-Champaign demonstrated the prototype for a portable, point-of-care COVID-19 molecular test kit.
In a new study published Monday, August 31, on the Proceedings of the National Academy of Sciences, the research team details a simpler process that can analyze the viral transport media and saves time by bypassing a few of the steps involved in existing COVID-19 testing methods.
LAMP Detection of COVID-19
Current tests for COVID-19 include taking a sample from the patient with a nasopharyngeal swab. The swab, with the patient's specimen, is then placed into a viral transport medium (VTM), which is a specialized container for holding and moving viruses/ samples while sustaining its viability.
The VTM is then sent to a lab for analysis, which requires a series of extraction, isolation, and replication of the target RNA inside the SARS-CoV-2 virus. Currently, reverse transcription-polymerase chain reaction (RT-PCR) is the most commonly used process in multiplying the RNA. However, according to Electrical and Computer Engineering Professor Brian Cunningham, RT-PCR requires a number of "temperature fluctuation cycles, specialized equipment, and trained personnel."
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The abstract of the new study notes the limitation of existing methods for the detection of the coronavirus - its reliance on "time-consuming, labor-intensive, and laboratory-based protocols" to isolate the virus, rip through its membrane and remove its inhibitors.
To work around this limitation, researchers demonstrated a detection method based on reverse transcription loop-mediated isothermal amplification, or RT-LAMP, to detect the coronavirus. Their experimental kit included a simple point-of-care (POC) instrument. Swabs were dipped into a substance that mimics nasal fluid, which is spiked with the coronavirus. The "sample" is moved through a VTM and sampled to perform under their isothermal RT-LAMP nucleic acid method.
Comparing the LAMP and the PCR assays revealed that RT-LAMP results are consistent with the PCR-based result. They also noted variations in terms of sensitivity and specificity.
A Portable POC Coronavirus Test Kit
The RT-LAMP assay was later installed into a small, 3D-printed microfluidic cartridge. It was designed to have two syringe input slots: one is for the sample-containing VTM and the other is for the LAMP substance. Once injected, the substances from both chemicals react inside the cartridge.
In terms of advantages, LAMP bypasses the RNA extraction and purification processes significantly reduce the time needed to return results. Furthermore, the LAMP assay requires only one temperature, 65 degrees Celsius, making it easier to control, explains first author Anurup Ganguli.
"We use modern, high-speed additive manufacturing to make these cartridges. The entire thing can be quickly scaled up to hundreds of thousands of tests," said Mechanical Science and Engineering professor Bill King. He also noted that production scale-up is among the largest obstacles faced by microfluidic cartridges that sought to be made commercially available. With their new design, manufacturing can be both elastic and scalable.
The University of Illinois, Urbana-Champaign team is reportedly working with a Chicago-based tech company co-founded by King, Fast Radius Inc., to ramp up the manufacture of the microfluidic cartridges.
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To use, the cartridge can be inserted inside a hand-held instrument with a heating chamber, heating the microfluidic cartridge to 65 degrees Celsius. A smartphone cradle can read the results within 30 minutes, with the instrument emitting fluorescent light.
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