Electrorotation of colloidal suspensions

We investigate the pressure effect on the eletrorotation (ER) spectrum of living cell suspensions by considering the particle shape effect. Based upon the spectral representation theory, we consider coated oblate spheroidal particles and present a theoretical study of ER spectrum. Analytic expressions for the characteristic frequency as well as the dispersion strength can be obtained, thus simplifying the fitting of experimental data. From the theoretical analysis, we find that the cell shape, coating as well as material parameters can change the ER spectrum. We demonstrate good agreement between our theoretical predictions and experimental data on human erythrocytes suspensions.