Study on the dielectric properties of biological cells using the electrokinetic method

Different from hard particles with an ordinary surface structure, a biological cell is a soft particle which can be described as a hard particle covered with an ion‐penetrable surface layer of polyelectrolytes. In this paper, according to the electrokinetic theory of suspension of soft particles, the colloid vibration current (CVI) model of suspended biological cells is investigated. A CVI measurement system is set up in which ultrasonic pulses of different intensities are calibrated and used. The experimental results on electrolyte solutions and cell suspensions show that CVI is closely related to the ion and cell concentration of the sample solution. Along with the increased concentration of ions or cells, the CVI signal increased initially and then decreased for electrolyte solutions, but it was the reverse for a chicken blood cell suspension but stayed almost constant for a spawn suspension. All these phenomena were caused by the interactive electrokinetic polarization of ions and cells under the action of ultrasonic pulses. Through the analysis of the electrokinetic course of the cell suspension, it was found that the amplitude and slope of the electrokinetic curve could be used to characterize the dielectric properties of cells. The electrokinetic model and CVI measurement system are rather feasible, as shown by the experimental results. The electrokinetic measurement method shows a new nondestructive way for studying the charging properties of biological cells, and the method has an inherent advantage for the real‐time study of the biological effects of ultrasound on cells. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.