NEW YORK – Startup Rover Diagnostics aims to make waves in the point-of-care space with an instrument incorporating novel optical thermal cycling and detection. The all-optical real-time PCR technology enables a low cost of goods for both system and assays, and the firm expects to initially launch into the infectious disease testing space with a CLIA-waived COVID-19 test.
Called LightSpeed, the system can perform sample-to-results real-time PCR in approximately 25 minutes, with a cost of goods of $1,500 for the instrument and approximately $5 per assay, according to RoverDx Cofounder and CEO Mark Fasciano.
Rover Diagnostics was founded in late 2018 by Fasciano and Sam Sia, a biomedical engineer at Columbia University. The company is located in New York City and was established to commercialize LightSpeed, Fasciano said.
The LightSpeed instrument uses a combination of plasmonic nanoparticle thermal cycling and fluorometry-based optical readouts, according to Sia. It is also portable, weighing approximately 2 pounds.
Plasmonic nanoparticles can be used in different aspects of diagnostics, for example as a detection technology in biosensors.
Rather than using them as sensors, Rover's system uses plasmonic gold nanorods to convert light to heat. The tiny particles are mixed with the PCR reagents and emit heat when illuminated with infrared LED lights, such that flashing the light on and off alternately with pulses from a cooling fan enables thermal cycling.
Sia noted that the particles had previously been used for PCR reactions, but typically they had only been used for singleplex endpoint PCR after the nanoparticles had been separated out because of the fluorescence-quenching properties of nanoparticles.
The team discovered that tweaking the concentration of the particles could get around the quenching. They also used a unique fluorescence approach incorporating a spectrometer to read multiple wavelengths, allowing for real-time multiplexing.
"We excite at one wavelength and read the whole spectrum out," Sia said. "We then deconvolve back the specific wavelengths," Sia explained.
This method also helps speed up testing, since it does not require changing optical filters or reading of multiple wavelengths. And, the testing is extraction-free, which also enables a faster workflow.
In a study published last month in Nature Nanotechnology, Sia and his team developed a COVID-19 assay detecting a target on the N1 gene from saliva and nasal swabs. In addition to proof-of-concept studies of the instrument, the team showed it had 100 percent sensitivity and specificity on a set of clinical samples when compared to qPCR testing using a Thermo Fisher QuantStudio 6 Pro instrument.
Regarding the 25-minute sample-to-results time of LightSpeed, Sia noted that his team hasn't yet pushed the system to its limits. "We could probably go faster," he said, noting that other researchers have used plasmonic nanoparticles to drive PCR in minutes using purified DNA.
Indeed, a group at McGill University in Montreal has published a method using nanoparticles to run 30 PCR thermal cycles in less than one minute with a standard 20 microliter sample volumes, although the team noted that more work will be required to develop polymerase enzymes that can efficiently extend DNA at those rates. The McGill team described real-time monitoring using their method in a conference presentation, which was undertaken in collaboration with Nanopartz, a gold nanoparticle supplier.
Andrew Kirk, a professor of electrical and computer engineering at McGill and corresponding author on the study describing the one-minute method, said in an email that the RoverDx Nature Nanotechnology study was "very impressive work."
Fluorescence multiplexing in the plasmonic PCR environment is "challenging," Kirk said. The system Kirk's team developed used lasers rather than LED lights, he said, adding that it might be more difficult to scale up the LED approach to a multichannel system. McGill has licensed the technology and it has been advanced to multichannel plasmonic PCR prototypes, he also said.
Fasciano noted that the Rover system may differ somewhat from the McGill team's work. "Because we are commercializing a system for clinical diagnostics, not just research-use-only, we need to be much more concerned about the performance targets, particularly sensitivity and specificity," he said.
Furthermore, because RoverDx is building a CLIA-waived, low-complexity device, the entire workflow — from test registration, LIS integration, clinical sensitivity and specificity, multiplex fluorometry, and results reporting — will be important, he also said.
The Rover team also operates a second company, called Rover Labs, which offers end-to-end diagnostic testing services.
For example, the company contracted to provide COVID-19 testing to more than 200 New Jersey public schools using saliva samples and Fluidigm testing from its lab site in Monmouth Junction, New Jersey. Including both PCR and antigen tests, the lab has delivered approximately 1 million tests in the first half of this year, Fasciano said.
The firm also markets a cloud-based LIS system called CloudLIS, Fasciano said. The system supports high-throughput testing and works with other commercial diagnostic systems, but will ultimately also be integrated into LightSpeed, he said.
Rover Labs is also helping inform the marketing targets and user needs for RoverDx, Fasciano said.
The future of POC MDx
Sia published a review of the commercialization of microfluidics-based point-of-care diagnostics in Lab on a Chip in 2014. The ecosystem has changed, of course, in the ensuing eight years, with the pandemic accelerating development and dozens of new systems funded and launched.
In a review last year, Sia and colleagues compared the design choices made by developers of 21 different POC systems.
"COVID accelerated a lot of the trends in point-of-care that we had been seeing," Sia said. This is happening both on the technical side, for example with novel assay chemistries and connected instruments, as well as on the nontechnical side with changes in reimbursement, regulatory guidance, legislation, and preferred clinical workflows.
For a system to be successful, Sia said the technology has to work well, but it also must fit with customers' workflows, serve up data in a helpful way, and have a competitive price.
COVID has not gone away yet, Sia also noted, and there are other infectious diseases, as well as trends in digital and consumer health that will support a growing market, as long as "the devices fit the market need."
Fasciano said the firm is targeting customers who run between 10 and 400 tests per week and four specific use cases: municipal users in schools, departments of transportation and corrections, and reimbursed users in pharmacies, physician offices, and assisted living facilities. The firm also hopes to target private corporations and contract research organizations developing companion diagnostics.
RoverDx has raised approximately $4.5 million in seed investment, Fasciano said, and also received Phase I funding from RADx-Tech in 2020. Rover Labs, meanwhile, is now a profitable and growing business, he said.
The company's regulatory plans are to submit the system along with a COVID-19 assay to the US Food and Drug Administration for Emergency Use Authorization. It also plans to expand its menu to include other infectious diseases in the future.