A Process to Realize 2PP-Based Electrodes in Microfluidic Channels

In this work, a process to realize metallized 2-photon-polymerized (2PP) structures in prefabricated microfluidic channels is presented, aiming at 3D-structured electrodes. The channel is fabricated using a single-layer process of SU-8 to realize vertical sidewalls with a height and width of 300 µm. Electrodes in a ring shape with an outer diameter of 250 µm are printed in the channel using 2PP and metallized via sputtering. Using chromium as sacrificial layer, a lift-off is performed to structure the metal. This allows us to fabricate individual electrically controllable 3D electrodes that use the total height and width of the channel. Metallization with good step coverage on ring-shaped 3D structures in the high microchannel was achieved, which was confirmed using conductivity tests.