Micro electrical impedance spectroscopy of bovine chromaffin cells

Single cell characterization using electrical impedance spectroscopy (EIS) has been conducted on bovine chromaffin cells. Measurements were taken using a micro scale electrophysiological analysis system fabricated using micromachining (e.g. MEMS) technologies. A population of chromaffin cells were injected into a microreservoir and subsequently manipulated into a microchannel with a cross-sectional area of 7.0/spl times/7.0 /spl mu/m/sup 2/. The microchannel was designed with integrated, opposing electroplated palladium electrodes with a cross-sectional area of 7.0/spl times/7.0 /spl mu/m/sup 2/. The electrodes are designed to be in contact with the cells during analysis procedures. Impedance measurements were taken over a frequency range of 40 Hz to 3.0 MHz. Magnitude and phase were studied for a statistically relevant population of chromaffin cells. The impedance spectrums revealed three distinct populations of chromaffin cells. The data obtained for the chromaffin cells was compared to data obtained for red blood cells, air, and phosphate buffered solution.