Enhancing dielectrophoresis effect through novel electrode geometry.

This paper presents an original device to enhance dielectrophoresis (DEP) effects through novel geometry of the electrodes. Implemented with a simple single-layer metal process, our microchip device consists of individually triangular-shaped electrodes in a parallel array. When activated with DEP waveforms, the novel-shaped electrodes generate horizontal bands of increasing electric fields. With these bands of electric fields, dielectric microbeads in a suitable medium can be manipulated to form a straight horizontal line at a predictable location over the electrodes. Further experiments show that the location of the microbeads is sensitive to the frequency of the applied DEP waveforms. By changing the frequencies, the line of microbeads can be shifted vertically along the electrodes. In addition, horizontal movements of the microbeads can be achieved with traveling wave DEP. With an accurate control of both vertical and horizontal positions and a potential multi-lane separation strategy, our device delivers substantial improvements over the existing electrode array devices.