Microfluidic-Based Electrical Impedance Spectroscopy System Using Multilevel Lamination of Dry Film Photoresist

Micro-electro-mechanical systems (MEMS) often require thick structures with high aspect ratios. To fulfill this specification, lamination of thick dry film photoresists (DFR) is preferred. To demonstrate the capability, we developed a microfluidic system, which consists of a 3-level laminated SUEX DFR with an aperture and served as a hydrodynamic trap. Two embedded vertically arranged electrodes around the aperture enabled electrical impedance spectroscopy ( EIS) on single microspheres. In a proof-of-concept, EIS measurements were carried out between 500 Hz and 1 MHz on a single poly(methyl methacrylate) (PMMA) sphere with a diameter of 100 mu m. The spectra were analyzed using an equivalent electric circuit model. A significant increase in impedance values was obtained by trapping the PMMA sphere in the aperture.

Automated summary

This study focused on the capability of building a microfluidic system using three-level laminated dry film photoresists, demonstrating the feasibility of performing electrical impedance spectroscopy on single microspheres and achieving a significant increase in impedance values by trapping the sphere in the aperture.