Fabrication and evaluation of 3D-electric micro filters using proton beam writing

Dielectrophoresis (DEP) is a phenomenon involving translational movement of a polarizable object toward the direction of the electric field gradient. DEP has been used for electrical trapping of food poisoning microbes such as Escherichia coli (E. coli). In this paper, we developed 3D-electric micro filters equipped with high-aspect-ratio pillar array with a height of ∼15 μm and a diameter of ∼1 μm as a part of the electric micro filter. The pillar array was fabricated using a 15 micrometer thick negative resist layer on silica substrate by proton beam writing (PBW). We analyzed a DEP force distribution around pillars in the 3D-electric micro filters. Making the most of superior features of PBW as a rapid prototyping tool, we evaluate the performance of the DEP device for trapping capability of E. coli by photoluminescence (PL) measurement for various arrangements of the pillars to achieve higher trapping efficiency of the 3D-electric micro filter.