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Integrate MXR into a diagnostic consumable

MXR isn’t the first microfluidic mixing device, but it is the first that can integrate with real-world diagnostic cartridges. MXR is easy to integrate into just about any consumable you can imagine. Including MXR in your product development plan is also straightforward, during early-stage R&D, late stage design for manufacturing, and anytime in between.

Early stage R&D with MXR

The easiest way to get started testing your assay with MXR is with a starter kit that includes a set of standard MXRs based on a 17 µL design. To assemble an MXR chamber, simply remove the adhesive backing from the chip, and press it firmly to a flat substrate, such as a microscope slide. The medical grade acrylic adhesive bonds to glass and most plastics. Our standard chip design has two circular ports, which mate cleanly with most P20 (0.5 – 200 µL) pipette tips. The ports enable direct filling and recovery of samples. If the assay is sensitive to evaporation, small seal tabs can be used to close the ports during incubation.

MXR is based on Redbud Post technology, which relies on magnetic fields to induce fluid flows. To enable R&D-stage experiments, we developed the Redbud Stage, a compact benchtop device that can drive up to two MXRs simultaneously. The speed of each driver can be controlled independently. Stage includes a heated platform that enables testing of temperature-sensitive assays, and there is plenty of extra space in the temperature-controlled chamber to preheat reagents, or to include control specimens for materials compatibility testing, or to evaluate the impact of mixing on your assay. To minimize the investment required to test MXR, Redbud Stage is available under a cost-effective monthly lease.

Cartridge integration

MXR ModuleOnce your team has shown that MXR can boost your assay performance—perhaps, for example, showing that mixing makes your assay faster or more sensitive—it is time to integrate MXR into your cartridge design. The same modular approach that makes MXR convenient for R&D stage testing makes it ideal for high-volume manufacturing and assembly.

Redbud Labs will work with your team to determine exactly the right MXR design for your application. We will determine your desired sample volume, x-y footprint, and Redbud Driverchamber height. For multiplexed assays, or for protocols that require sequential mixing, we will establish the desired number of mixing chambers for the application; these will be patterned into a single chip. The pipette ports will be removed. Similarly, we can review your instrument design to identify the easiest way to integrate a magnetic driver. A wide variety of motor-magnet configurations can be made to work, depending on the mechanical constraints of your existing design.

Example: an injection molded, highly manufacturable cartridge with MXR

How does this integration work in practice? Consider this cartridge, which was developed for a 4-plex diagnostic assay. It meets several demanding specifications listed below:

  • Requires less than 100 µL of whole blood
  • Divides the sample into four channels, each with a different dried reagent
  • Precisely meters 22 µL per channel (± 1 µL)
  • Tightly controls the time at which the sample and reagents are combined (±0.1 s)
  • Highly manufacturable design using conventional injection molding, die cutting, and ultrasonic welding
  • Optically clear surfaces
  • Cost of goods (excluding MXR) is less than $2

In this application, our goal is to introduce MXR to the detection region without substantially increasing the cost of the consumable and without complicating the operation of the existing, high-precision features in the cartridge.

Example Cartridge

To accomplish these goals, we created an MXR with four “rounded rectangular” chambers. In a single assembly step, the MXR bonds to the cartridge using PSA. The four samples are introduced into the chambers through four “vias”—channels that traverse the thickness of the cartridge chassis. The sample runs to the other end of each chamber, then out through a venting via. The vent is covered on the opposite side by a vapor-permeable membrane.

The result is a highly manufacturable cartridge that takes full advantage of MXR.

Are you developing a cartridge that requires microfluidic mixing? To discuss integrating MXR into your cartridge, contact us.

Latest news:

PRESS RELEASE- Redbud Labs Expands Leadership Team

Redbud Labs has announced new members of leadership as the company poises for upcoming growth. Experienced leaders in the pharmaceutical/life sciences industry, Kathryn Lawrence and Dale Barnes join Jay Fisher who continues leadership of R&D efforts. Kathryn will head the commercial team and Dale Barnes will lead manufacturing efforts. To learn more, visit

See Redbud @ Lab on a Chip World Congress

Redbud Labs is proud to be a sponsor of the Lab on a Chip World Congress in Coronado Island CA. Richard Spero, CEO, will be giving a talk titled Low-Concentration Samples: The Next Diagnostic Frontier on Wednesday, October 3rd at 9:00am. Come hear the latest on MXR,...

Redbud Labs announces new headquarters

Redbud Labs announced today a move to the newly renovated 400 building on the Frontier campus in Research Triangle Park. Our headquarters will comprise 8,000 square feet, including a production suite for manufacturing of MXR and future products. Laboratory spaces will...

PRESS RELEASE-MXR now available for microfluidic ChipShop products

microfluidic ChipShop GmbH today announced that its products are now available with MXR, the world’s fastest, most adaptable microfluidic mixing chip. By adding MXR to microfluidic ChipShop products, assays can benefit from mixing when, where, and how they need it. Thanks to its unique, pop-in design, MXR offers easy integration with any product in the ChipShop catalogue.


We collaborate with your engineers to develop cost-effective solutions tailored to your cartridge design.

Contact us to get started.

Redbud Labs

Offices, Production, and Labs
400 Park Offices Dr. #301
RTP NC 27709


PO Box 13195
RTP NC 27709

(919) 537-9753

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