Dielectrophoresis tweezers for single cell manipulation.

Positioning single cells is of utmost importance in areas of biomedical research as diverse as in vitro fertilization, cell-cell interaction, cell adhesion, embryology, microbiology, stem cell research, and single cell transfection. Here we describe dielectrophoretic tweezers, a sharp glass tip with electrodes on either side, capable of trapping single cells with electric fields. Mounted on a micromanipulator, dielectrophoresis tweezers can position a single cell in three dimensions, holding the cell against fluid flow of hundreds of microns per second with more than 10 pN of force. We model the electric field produced by the tweezers and the field produced by coaxial microelectrodes. We show that cells are trapped without harm while they divide in the trap. In addition, dielectrophoretic tweezers offer the possibility for trapping, electroporating, and microinjecting a single cell with one probe.