Originally Published MPMN October 2008

BREAKTHROUGHS

Company Channels Microfluidic Knowledge to Produce Multilayer Devices

Shana Leonard

Allowing for fluid control and analysis on a small scale, microfluidics have generated substantial buzz in the life sciences industry as the potential for lab-on-a-chip technologies is explored. Prompting progress in this field, Dolomite has developed and fabricated large-scale multilayer microfluidic devices that could enable the production of cheaper, more-intricate lab-on-a-chip designs than are possible with single-layer chips.

“A single-layer chip has layout restrictions—imagine trying to design a road network with no bridges or tunnels!” explains Richard Gray, head of sales for Dolomite. “A multilayer chip allows complex routing patterns for more-sophisticated tasks such as managing mixing, residence, and output flows.”

Currently engineering three-layer devices, the company cites design freedom as a significant benefit of multilayer devices because each layer of the chip can have a different etch depth, according to Gray. Single-layer chips, on the other hand, only feature an etch depth of one channel, therefore inhibiting functionality.

Resembling electronics manufacturing, the fabrication of multilayer microfluidic devices relies heavily on photolithography masks in order to expose the channels to be etched on materials such as glass. After creating the channel layout using 3-D modeling and flow-simulation software, Dolomite converts the models to 2-D layer drawings and makes photolithographic masks. Once the material has been etched, the company then precision drills the patterned layers to produce interlayer connections, after which the layers are cleaned, aligned, and fused together to form a single entity. Individual microfluidic devices are then obtained by dicing the multilayer wafer.

Gray notes that, in addition to glass, multilayer chips can be constructed using plastic. “Dolomite is developing novel technology to allow plastic devices to be developed without the need to invest in high-cost injection mold tooling until production rates are at very high levels. This makes midlevel devices affordable, and also delays the need for a device manufacturer to make a commitment to expensive mold tooling until after the device has been well proven in trials,” he adds.

Applications for the multilayer microfluidic devices include chemical synthesis, nanoparticle manufacturing, and cell sorting. They are also suitable for use in diagnostic systems and analytical processes such as chromatography and polymerase chain reactions.

Dolomite, Charlestown, MA
www.dolomite-microfluidics.com

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