High Resolution 3D Printing for Microfluidics
Gregory Nordin,
Professor,
Brigham Young University
While there is great interest in 3D printing for microfluidic device fabrication, a main challenge has been to achieve feature sizes that are in the truly microfluidic regime (<100 µm). A key issue is that microfluidic devices are comprised primarily of negative space features, which therefore dominate 3D printing resolution requirements, as compared to positive space features that are typical for many other 3D printing applications. Consequently, we have developed our own stereolithographic 3D printers and materials that are specifically tailored to meet these needs. We have shown that flow channels as small as 18 µm x 20 µm can be reliably fabricated, as well as compact active elements such as valves and pumps. With these capabilities, we demonstrate highly integrated 3D printed microfluidic devices such as a 10-stage 2-fold serial dilutor that simultaneously creates a 3 order of magnitude range of concentrations, high density chip-to-chip interconnects (53 interconnects per square mm) that are directly 3D printed as part of a device chip, and droplet-on-demand structures to efficiently entrain individual bacteria in relatively few droplets despite initial large sample volume. These advances open the door to 3D printing as a replacement for expensive cleanroom fabrication processes, with the additional advantage of fast (~5-15 minute), parallel fabrication of many devices in a single print run due to their small size.
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