Optical Diagnostics of Mechanical Properties of Red Blood Cells based on the Deformation by High Frequency Electric...

Erythrocyte placed in a low-conductivity isotonic medium can be elongated by a high frequency electric field. The elongation can be registered optically, finally enabling the determination or monitoring of elastic moduli and viscous properties of erythrocytes. However, an unambiguous evaluation of mechanical parameters from the optical data is complicated. It requires an adequate theory of dielectro deformation which takes into account the influence of the cell's mechanical, electric, and transient shape parameters on field-induced deformations. The present work is aimed at the development of a comprehensive and experimentally verified theoretical basis for the dielectro-deformational investigation of erythrocytes. The previous concept of the dielectro-deformation process, supported solely by the shear deformation of erythrocyte membrane, is revised completely. It is shown that in the practical relevant range of dielectro deformation, it is mainly supported by bending deformation of the membrane, with a gradual development of shear deformation as the cell becomes more elongated. This new bending-shear theory of dielectro deformation is developed here. The theory is shown to describe unambiguously both observational and quantitative data on the static and dynamic dielectro deformation of erythrocytes. © 1999 Society of Photo-Optical Instrumentation Engineers.