A combined dielectrophoresis, traveling wave dielectrophoresis and electrorotation microchip for the manipulation and characterization of human malignant cells.

The study of the dielectric properties of micrometer- or nanometer-scale particles is of particular interest in present-day applications of biomedical engineering. Electrokinetics utilises electrically energised microelectrode structures within microfluidic chambers to noninvasively probe the physiological structure of live cancer cells. A system is described that combines the three complementary techniques of dielectrophoresis (DEP), travelling wave dielectrophoresis (TWD) and electrorotation (ROT) for the first time on a single, integrated chip (3 x 6 mm). The chip employs planar microelectrode arrays fabricated on a silicon substrate to facilitate the synthesis of the various nonuniform electric fields required for the controlled manipulation, measurement and characterization of mammalian cells. A study of the dielectric properties of human malignant cells (Daudi and NCI-H929) was performed to demonstrate the potential and the versatility of the system in providing a fully programmable microsystem.