Research on the electrokinetic method for studying charging properties of biological cells

Because of the existing of carboxyl, amino, phosphate and other ionic groups in the cell membrane, the suspended cell has a uniform negative surface charge and is coated with a double layer. The special composition structure makes the cell membrane partially penetrable for water and ions. Based on above characters of cell, the charging properties of micronsized biological cell can be studied using the electrokinetic method of soft particle. In this paper, according to the electrokinetic theory of a suspension of soft particles and the model of unit cell, the electrokinetic model of cell suspension was studied. And according to the electrokinetic theory, the colloid vibration current (CVI) measurement system was set up. The theoretical and experimental results on cell suspension showed that electrokinetic currents were closely related with the cell concentration of the sample solution. Along with the increased concentration of cells, the electrokinetic current decreased initially and then increased, finally decreased again for cell suspension. All these phenomena were caused by the interactive electrokinetic polarization of ions and cells under the action of ultrasonic detecting pulses. Through the analysis of the electrokinetic course of cell suspension, it was found that the slope of the electrokinetic curve could be used to characterize the charging properties of cells. The electrokinetic measurement method may show a new non-destructive way for studying charging properties of biological cells, especially for the research of bioelectromagnetics.