Off-chip electrode insulator based dielectrophoresis

We present the first reported off-chip electrode, insulator-based dielectrophoresis microchip (ODEP). In contrast to previous off-chip DEP efforts, the DEP forces are enhanced by the insulating structures within the channel, enabling higher sensitivity and throughput as well as low frequency operation. The device was tested by selectively concentrating Escherichia coli (E. coli) and Salmonella typhimurium, two known waterborne pathogens, from water samples at flow rates as high as 1200 μl/hr. In order to demonstrate the ability to selectively concentrate bacteria, separation of bacteria and polystyrene beads was performed.