Abstract

High Resolution Negative Space 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 3D printed channels as small as 18 µm x 20 µm, and have recently reduced this to 2 µm x 2 µm. We have also developed active elements such as valves and pumps with the smallest valves having an active area of only 15 µm x 15 µm. In this presentation we discuss how such results are achieved and demonstrate miniaturized components including small (<1mm^3) fast (~1 ms) mixers and isoporous membranes with 7 µm pores. We also demonstrate integrated 3D printed devices such as for controllable cell chemotaxis. Advances in negative space 3D printing open the door to replacing expensive cleanroom fabrication processes with 3D printing, with the additional advantage of fast (~5-15 minute), parallel fabrication of many devices in a single print run due to their small size.