Cell Physiometry Tools Based on Dielectrophoresis

A cell physiometry system is described for characterizing and separating cells, and performing cell-based assays, using dielectrophoresis (DEP). Cells, or mixtures of cells, are suspended in a chamber containing an array of microelectrodes located on the chamber's bottom surface. A sequence of radio frequency signals is automatically applied to the microelectrodes, and images of the DEP-induced motions of the cells are captured and analyzed to determine a characteristic parameter known as the DEP cross-over frequency. Once a cell population has been characterized in this way, the same apparatus can be used to selectively isolate cells for additional biochemical, physical, or genetic analysis. Biochemical labels or bioengineered tags such as fluorescent markers or antibody-coated beads are not required. Cell separations are achieved by “electronically tuning” into the different cell types by superimposing different signal frequencies onto the microelectrodes, using both stationary and traveling wave DEP signals. Examples of separating different types of blood cell are given, together with descriptions of cell-based bioassays that monitor physiological changes that accompany trans-membrane signaling events, apoptosis, and the aging of cell cultures.