Sample preparation by cell guiding using negative dielectrophoresis

In this study, we present a microsystem designed for performing and testing dielectrophoretic (DEP) guiding of biological cells. Baker’s yeast (Saccharomyces cerevisiae) is used as a model organism to study cell guiding in the system. The guiding efficiency as a function of flowrate is investigated and a decreased efficiency with increased flowrate is observed. In addition, the DEP behaviour of the yeast cells at different medium conductivities and applied frequencies is investigated. The chip is easily fabricated in a two-step process: Standard UV lithography techniques are used for electrode fabrication and laser ablation for channel structuring. The channel is sealed with an indiumtinoxide (ITO) covered polymethylmethacrylate (PMMA) lid. The ITO serves as a transparent counter electrode. This conducting and transparent lid eliminates difficult top/bottom electrode alignment and gives visual access to the microchannel.