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Rheonix Unveils 'Channel-Free' Microfluidic Device for Molecular Testing Platform


SAN FRANCISCO — Molecular diagnostics developer Rheonix this week shared details about its recently developed "channel-free" microfluidic device, which it claims is the first of its kind and will enable the company to expand the depth and breadth of applications for its integrated molecular testing platform.

In addition, Rheonix provided details about how its technology is being used in its ongoing food safety testing collaboration with Life Technologies.

In a presentation in the Biospecimen Science and Sample Prep program of Cambridge Healthtech Institute's Molecular Medicine Tri-Conference, held here this week, Richard Montagna, Rheonix's senior vice president for scientific and clinical affairs, discussed the company's latest microfluidics breakthrough, the Smart FilmCARD.

The new device is the second generation of the company's existing "chemistry and reagent device" (CARD) technology, a consumable cartridge that has to this point been the linchpin of Rheonix's product-development efforts.

About the size of a credit card, the CARD consumable is inserted into the company's Encompass MDx system to run multiple samples through nucleic acid extraction and purification, amplification, and either real-time PCR or array-based endpoint detection.

The CARD can handle liquid volumes of between 5 µl and 5 ml and tissue mass up to 20 mg, and is compatible with a broad range of sample types including fresh tissue, FFPE tissue, whole blood, serum, saliva, and swabs.

During his Tri-Con presentation, Montagna noted that the current CARD consumable is an inexpensive plastic device that contains all required functionalities — such as valves, bidirectional pumps, and reagent reservoirs — for moving a nucleic acid assay through its various stages. Individual diaphragms on the CARD device can operate as open or closed valves or as bi-directional pumps, all controlled through pneumatics with dedicated software.

The company does not publicly disclose the cost of the CARD consumable, but it claims that the inexpensive microfluidics architecture and laminated plastic design make it a relatively low-cost, high-margin disposable.

With its new technology, however, Rheonix believes that it can reduce the cost of the CARD platform even more, Montagna said this week.

Compared to CARD, the Smart FilmCARD uses a deformed gasket wall to replace channels and create a microfluidic network in a honeycomb design. Fluids are moved from cell to cell of the honeycomb via vacuum control, resulting in a "wave" of pneumatic signals — negative pressure followed by positive pressure and so on — that Montagna likened to a neuronal circuit firing.

The channel-free design permits controlled movement of fluids anywhere on the Smart FilmCARD while virtually eliminating dead-volume losses typical of channeled devices, according to the company.

Furthermore, Montagna noted, the consumable is simpler to manufacture than the existing CARD device, and reagents can be easily packaged on board.

The upshot of these innovations is that Rheonix now expects to be able to address "diverse market requirements that are too difficult to perform with existing systems, such as automated next-generation sequencing library sample preparation, low-cost infectious disease panel testing, and point-of-care applications," the company said in a statement. "It also enables Rheonix to serve markets requiring small-volume reagent management, onboard reagents, and simpler testing procedures."

Montagna did not say when the company expected the next-gen consumable to be commercially available. The company noted in a statement that it will continue Smart FilmCARD development efforts within its newly formed Rheonix Innovation Center under the direction of CSO Peng Zhou, who holds 14 US patents to various technologies including applications related to the new channel-free technology.

Montagna also said at Tri-Con that Encompass MDx system users will be able to quickly and easily upgrade the platform to accommodate the new consumable architecture.

Meantime, Rheonix continues to develop its own molecular diagnostic tests for CARD and Encompass MDx, particularly syndromic panels for markets such as women's health, hospital-acquired infections, and respiratory and gastrointestinal diseases.

Parallel to that effort, the company has an ongoing collaboration with Life Technologies — now a part of Thermo Fisher Scientific — to develop the CARD consumable and a dedicated instrument platform for food safety testing.

Announced last July, this collaboration is intended to eventually yield a sample-to-result molecular testing system to complement Life Tech's existing food safety product portfolio.

And while Rheonix has in the past stressed the ability of its system to perform multiplexed endpoint detection of PCR products using an integrated array — up to 48 targets per CARD device — it has also developed real-time PCR capabilities for the device for smaller numbers of targets as part of the Life Tech project.

In an email to PCR Insider following Montagna's presentation at Tri-Con, Steve Pemberton, vice president of marketing and sales at the company, discussed this modification as well as other details about technology development efforts under the Life Tech agreement.

"The applications as envisioned [in the Life Tech partnership] will incorporate real-time detection of enteric foodborne illnesses, such as Escherichia coli, Listeria spp., Shigella spp., Salmonella spp., et cetera, and accompanying endpoint detection of species and/or serotypes," Pemberton said.

"We are on track to accomplish this through the incorporation of a unique Rheonix-devised qPCR optical unit, utilizing Life Tech-provided dyes, coupled with endpoint detection on already-established Rheonix microarray technology — the Hy-Fi Microarrays in a coupled detection paradigm, or orthogonal detection," Pemberton added. "We have also established orthogonal methods of purification such as combining silica filtration purification with a second-stage magnetic bead purification. In short we can couple best-in-class detection either orthogonally or singly, and best-in-class purification, orthogonally or singly, to meet the specific needs of any particular assay."