Automated real-time measurement of chemotactic cell motility.

We have developed a novel method, (ECIS/taxis), for monitoring cell movement in response to chemotactic and chemokinetic factors. In this system, cells migrate in an under-agarose environment, and their positions are monitored using the electric cell-substrate impedance sensor technology to measure the impedance change at a target electrode, that is lithographed onto the substrate, as the cells arrive at the target. In the studies reported here, Dictyostelium discoideum was used as a prototypical, motile eukaryotic cell. Using the ECIS/taxis system, the arrival of cells at the target electrode was proportional to the dose offolate used to stimulate the cells and could be assessed by changes in resistance at the electrode. ECIS/taxis was readily able to distinguish between wild-type cells and a mutant that is deficient in its chemotactic response. Finally, we have shown that an agent that interferes with chemotactic motility leads to the delayed arrival of cells at the target electrode. The multi-well assay configuration allows for simultaneous automated screening of many samples for chemotactic or anti-chemotactic activity. This assay system is compatible with measurements of mammalian cell movement and should be valuable in the assessment of both agonists and antagonists of cell movement.