Fabrication of microfluidic devices for emulsion formation by microstereolithography

Abstract

Droplet microfluidics—the art and science of forming droplets—has been revolutionary for high‐throughput screening, directed evolution, single‐cell sequencing, and material design. However, traditional fabrication techniques for microfluidic devices suffer from several disadvantages, including multistep processing, expensive facilities, and limited three‐dimensional (3D) design flexibility. High‐resolution additive manufacturing—and in particular, projection micro‐stereolithography (PμSL)—provides a promising path for overcoming these drawbacks. Similar to polydimethylsiloxane‐based microfluidics 20 years ago, 3D printing methods, such as PμSL, have provided a path toward a new era of microfluidic device design. PμSL greatly simplifies the device fabrication process, especially the access to truly 3D geometries, is cost‐effective, and it enables multimaterial processing. In this review, we discuss both the basics and recent innovations in PμSL; the material basis with emphasis on custom‐made photopolymer formulations; multimaterial 3D printing; and, 3D‐printed microfluidic devices for emulsion formation as our focus application. Our goal is to support researchers in setting up their own PμSL system to fabricate tailor‐made microfluidics.