Impedance Sensing of Biological Processes in Mammalian Cells

Cellular impedance biosensors offer an alternative to conventional analytical techniques with potential advantages over optical methods of high speed, accuracy, sensitivity, non-invasiveness, and ease of direct computer analysis. We first review the original examples of impedimetric sensing where there were several tens or hundreds of cells on the electrodes. Recent works have dealt with single cells. We will highlight impedance sensing for cells grown on electrodes, as this method allows the study of the motion of mammalian cells in real time and in conditions as close as possible to their in vivo environments. Working at alternating current of low frequencies, it is possible to probe intrinsic properties of the cells and their interaction with substrates. In some cases, electrical measurements have been shown to be sensitive to changes in cell properties that are not visible optically. Possible applications may be relevant to a wide range of subjects, such as wound healing, mitosis and pharmacological apoptosis.