Development of dielectrophoretic devices with high-aspect ratio microstructures using proton beam writing

Shiine, Yasuharu*; Nishikawa, Hiroyuki*; Furuta, Yusuke*; Sato, Takahiro; Ishii, Yasuyuki; Kamiya, Tomihiro; Nakao, Ryota*; Uchida, Satoshi*

New types of electric micro filter with the high-aspect-ratio structures having a capability of electrically trapping food poisoning bacteria such as Escherichia coli () were developed as an application of the Proton Beam Writing (PBW). A 14-m-thick negative-resist layer of SU-8 was spin-coated, as a specimen, on a silica substrate a part of which was, in advance, covered with a pair of Au thin layer electrodes on its surface. High-aspect-ratio pillar arrays were fabricated by PBW. In this study, the trapping capability of the high-aspect-ratio pillar arrays was evaluated using the suspension including stained with SYTO9. The photoluminescence (PL) from the stained trapped among the pillar arrays in the Au electrode gap was measured for the evaluation by applying an AC voltage to its Au electrodes, flowing the suspension. We also evaluated electric micro filters with and without the pillar arrays for the trapping capability. The amount of the stained trapped among the pillar arrays was higher than the conventional electric micro filter without pillar arrays. The improved performance of the new electric micro filter is reported on the basis of changing the height and spacing of the pillars.