3D Wiring Microelectrodes in a PMMA Microfluidic Device by Vacuum Filling Method

Abstract In order to establish a detection and actuation system for 3D printed microfluidics, it is necessary to fabricate the 3D wiring microelectrodes. In this paper, a method is proposed that enables the fabrication of 3D wiring microelectrodes of several tens of micrometers in arbitrary designs. In the proposed method, attaching a lid made of polydimethylsiloxane (PDMS) on a 3D printed microfluidics, the introduction of low‐melting‐point alloy (LMA) into the 3D printed microchannel by the vacuum filling method is achieved. Theoretical models for predicting the LMA filling results and gained insights into the working principle of the proposed method have been established. Using this vacuum filling method, microelectrodes 50 µm width and height inside the 3D printed microchannels is successfully fabricated. Additionally, the design flexibility of the method is shown in the fabrication of 3D wiring microelectrodes in custom 3D shapes such as dead‐end electrodes, coil electrodes, and pillar electrodes. Furthermore, the sorting of live/dead spheroids by dielectrophoresis generated with the 3D wiring electrodes is demonstrated. It is believed that the proposed method will be highly beneficial in the field of microengineering, particularly in the context of 3D printing technology.