Multiple-frequency impedance measurements in continuous flow for the evaluation of electrical lysis of yeast cells

This paper reports on an electrical lysis device with integrated cell counting and evaluation of the lysis efficiency by multiplefrequency impedance measurements. Conventional techniques use chemical reagents to lyse cells, causing unwanted interference with possible intracellular content analysis downstream. Electrical lysis is quite simple to implement but optical observation of the lysis is difficult in the case of yeast cells, as lysis induces no visual difference. Counting the lysed cells is also essential for analysis downstream to provide an estimate of the analyte concentration per cell. Although cell counting can be performed by impedance measurement at one single frequency, multiple-frequency measurements allow the differentiation between living and dead cells and the evaluation of the lysis efficiency in continuous flow. The presented device could further be used for the evaluation of the lysis of other cell types, such as bacteria or mammalian cells.