Multilayer Electrodes DEP Chip for Single-cell Level Impedance Measurement

The authors demonstrated the capability of cell trapping with combination of dielectrophoresis (DEP) and 3D microstructures array in the prior work (Chen-Hsin Chuang, 2006). In the present study, in order to measure the variation of electric properties for a single cell under biochemical reactions, a novel design of multilayer electrodes is utilized to achieve both DEP positioning and impedance measurement with single-cell resolution. In this chip, three electrodes are separated by flow chamber and SU-8 holes array, respectively. Firstly, bioparticles can be trapped in SU-8 holes array by applying AC power on top ITO electrode and middle Au electrode on SU-8 surface. According to experimental results, the trapped bioparticles will be constrained in stationary due to microstructures for a long period of time without applying DEP force. Sequentially, the impedance measurement for bioparticles or cells can be performed by LCR meter. As the results shown, the resulting impedance can be varied by the size of trapped bioparticle. Therefore, this study not only provides an efficient way for trapping cell but also an alternative way to identify the size of particles by impedance measurement.