Stemnovate creates rapid detection kit for Covid-19
Stemnovate has developed a rapid detection kit-on-a-chip for the Covid-19 virus.
The Babraham Research Campus-based molecular biology and microengineering company says the kit overcomes the drawbacks with current PCR-based testing and offers an economical solution suitable for deployment at businesses, care homes, airports and other key locations.
The company, renowned for its organ-on-chip technology, says the nucleic acid testing kit offers another significant advantage over other commercially available tests: the same biochip could be used downstream to identify the exact viral strain infecting a patient, which could be important in monitoring and managing outbreaks.
Dr Ruchi Sharma, CEO and founder of Stemnovate, tells the Cambridge Independent: “These features are not available in any other commercial kit available so far.
“Stemnovate has consulted the regulators and is following guidance on CE compliance.
“We want to reach out to funding bodies, airport authorities and investors to scale up our manufacturing, and to businesses and laboratories interested in offering a testing service to meet the UK and global need.”
Stemnovate’s kit uses its proprietary lab-on-chip technology to capture, enrich and amplify two conserved SARS-CoV-2 specific genes that include Orf1ab and nucleocapsid (N). These are essential for the virus’ replication and structural integrity.
Using samples from throat and mouth swabs, the kit features a sensitive compound that can detect picogram levels of nucleic acid, and includes positive and negative control reactants to give endpoint data confidence. Stemnovate says highly accurate results can be returned in 70 minutes.
“The method utilises virus-specific probes attached on the biochip manufactured by Stemnovate,” explains Dr Sharma. “The reaction mixture is ready to use which, combined with the colorimetric readout, allows for easy detection.”
Any lab working at biosafety level one would be able to conduct the Covid-19 tests using the technology.
“It can increase testing capacity, and it can be deployed easily,” adds Dr Sharma. “It can be mass-produced.
“It’s a small handheld device. The kit comes with the chip and the reagent, which you put in defined areas on the chip. You bring it to a particular temperature for an hour and it is done.”
Current testing is based on RT-PCR, or reverse transcription polymerase chain reaction technology, which converts RNA from the sample into DNA, then uses heat to amplify the signal, typically taking a few hours.
“It is a common technique to study gene expression in laboratories around the world,” says Dr Sharma. “However, it is a multistep protocol and requires a thermocycler for making millions of copies of the gene of interest, which is a limitation for upscaling and the broad deployment of Covid-19 testing. Another area of concern is the 20 to 30 per cent false-negative results in RT-PCR based methodologies presently used in the field.”
An alternative technique also available for Covid-19 testing is RT-LAMP, or reverse transcription-loop-mediated isothermal amplification. This uses four primers to target the viral RNA, which is amplified, enabling results to be visible to the naked eye via a colorimetric change within about half an hour.
But this technique also has its drawbacks.
“The problems identified in RT-LAMP include the use of multiple primers – forward, backwards, inner and loop – that can result in unwanted primer-to-primer interaction and endpoint colour change discrepancy,” says Dr Sharma.
“Stemnovate’s rapid detection kit technology offers a solution in the highly specific conserved long probes, all which have been chemically immobilised on the chip and ready for use.”
SARS COV-2 belongs to a family of coronaviruses, which also includes SARS and MERS. As tiny errors occur in the genetic code during the replication of the virus, different variants emerge.
The evolution of Covid-19 could, in time, affect the potential success of therapies or vaccines, so monitoring strains of the virus will be important.
Stemnovate’s technology enables testing to be combined with such analysis.
The smart design of the probes allows cleavage for downstream evaluation, enabling viral strain sequencing and identification.
“Library-prepped samples can be subsequently analysed using bioinformatic rendering platforms,” says Dr Sharma.
Partners interested in helping Stemnovate scale-up manufacturing of the technology can contact ruchi.sharma@stemnovate.co.uk.
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