A Plug-and-Play Volume Minimizing Micromixer.

Microscale fluid mixing has numerous applications where rapid and efficient mixing is required, including drug discovery, bio-analysis and point-of-care diagnostics. Conventional soft lithography processes, however, make the integration of robust and reliable mixing difficult to implement in practice, especially across different flow rates. Here a 3D-printed plug-in micromixer designed for rapid and modular integration with microfluidic devices that addresses long-standing integration challenges for micromixing in microfluidic devices is presented. The micromixer is based on the split-and-recombine (SAR) channel topology employing an optimized 3D geometry, minimizing internal volume and fluidic resistance. A micromixer with 60-µm internal channels is fabricated and experimentally tested, demonstrating efficient mixing while maintaining a reliable seal with a PDMS microfluidic device. Accordingly, the modular micromixing device enhances the efficiency and usability of microfluidic systems, offering a promising solution for biomedical and analytical applications. This conceptually elegant plug-in approach represents a unique advance in the practical integration of 3D printed functionality with microfluidics devices.