Biological cells like any other material do conduct electricity. Though they come across as insulators, the resistance to the flow of current, i.e. impedance, could be used to characterize the cell itself. In this aspect, the impedance of cells can be a promising tool to investigate the state of the cell.

A simple way of measuring the impedance would be a planar-microelectrode method. The cells are contained in culture medium while measurements are taken with micro-electrodes fabricated on top of a substrate. Since both the probe "tips" do not come in contact with the probed object, the impedance to be measured includes some components apart from that contributed by the cells.

There have been publications reporting the usage of impedance of a cell to determine changes in the state of cells due to healing, drug candidate testing, functional genomic studies and so on.

In this thesis, an effort has been made to measure the impedance of cells. Further, a component of the sensor, the passivation layer has been investigated for its contribution to the measured impedance in a quantitative manner.