Pencil lead microelectrode and the application on cell dielectrophoresis

The microelectrode was used to perform dielectrophoresis of polystyrene latex microbeads (nominal diameter of 3 μm) and human red blood cells. A conducting glass (indium tin oxide coated glass, 40 mm × 40 mm × 1 mm) served as the counter electrode (0.5 mm beneath the microelectrode) to generate the asymmetrical electric field and also as the window for microscopic observation. With the sinusoidal bias voltage (30 Vrms) ranged from 20 Hz to 2 MHz, positive and negative dielectrophoretic phenomena were identified.