Determination of the Static Permittivity of Individual Red Blood Cells and Their Membranes by Electrostatic Force Microscopy

The results of determination of the static permittivity of individual red blood cells (RBCs) and their membranes by dc-electrostatic force microscopy are presented. This method is based on a quantitative analysis of the cross-sectional profiles of experimental electrostatic images. A model of electrostatic interaction between the cantilever tip and a biological cell of disk shape is proposed. The obtained permittivity of individual RBCs agrees well with published data. Calculation of the permittivity by the effective medium approximation for RBCs is performed for comparison with the mean value of the RBC permittivity of our model.