Monitoring impedance changes associated with motility and mitosis of a single cell.

We present a device enabling impedance measurements that probe the motility and mitosis of a single adherent cell in a controlled way. The micrometre-sized electrodes are designed for adhesion of an isolated cell and enhanced sensitivity to cell motion. The electrode surface is switched electro-chemically to favour cell adhesion, and single cells are attracted to the electrode using positive dielectrophoresis. Periods of linear variation in impedance with time correspond to the motility of a single cell adherent to the surface estimated at 0.6 mu m h(-1). In the course of our study we observed the impedance changes associated with mitosis of a single cell. Electrical measurements, carried out concomitantly with optical observations, revealed three phases, prophase, metaphase and anaphase in the time variation of the impedance during cell division. Maximal impedance was observed at metaphase with a 20% increase of the impedance. We argue that at mitosis, the changes detected were due to the charge density distribution at the cell surface. Our data demonstrate subtle electrical changes associated with cell motility and for the first time with division at the single-cell level. We speculate that this could open up new avenues for characterizing healthy and pathological cells.