Ivar Giaever

A Biosensor for Cells in Tissue Culture

Wednesday, 30 June 1999
11:35 - 12:20 CEST


Great advances have been made in quantifying biochemical and physiological activities in cultured cells. It has, however, been difficult to quantify changes of cell morphology. A method has now been developed that can continuously and non-invasively track morphological changes of adherent cells and provide quantitative data from both sparse and confluent cultures.

In Electric Cell-substrate Impedance Sensing (ECIS), cells are cultured on small (0.001 cm²) gold film electrodes whose impedance is measured wihth a 1 micro amp current, generally at 4000 Hz; normal tissue culture medium serves as the electrolyte. When cells attach and spread on these electrodes, their insulating membranes constrain the current and force it to flow beneath and between the cells. This results in large impedance changes. Furthermore, alterations in cell morphology give rise to variations in impedance that can be numerically analyzed to report levels of cell motility and, indirectly, cell metabolism. The approach is exceedingly sensitive and is capable of detecting changes in cell morphology on the order of nanometers, well below the resolution of an optical microscope.

ECIS is a very useful tool to study behavior of cells in issue culture but this method also have many potential applications. Presently we are investigating the use of ECIS for in vitro toxicology, drug efficacy and discovery, calcium and other oscillations, determination of metastatic potential and as a high throughput screening device.

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