Simulation of translational dielectrophoretic velocity spectra of erythrocytes in traveling electric field using various volume models

Abstract

Proper models of cell geometry are needed for biophysical analysis of cellular electrical phenomena. This work compares various mathematical volume-models for normal human erythrocytes (discocyte) possessing biconcave-discoid form to simulate translational dielectrophoretic velocity spectra of erythrocyte suspensions induced in a traveling electric field over a frequency range from 1 kHz to 15 MHz. The non-spherical volumes of the oblate-spheroid, the prolate-spheroid, and the oval of Cassini and the “Bun-model” were numerically evaluated according to the normal range of cellular dimension values for mammalian erythrocytes. The latter model is the novel approach derived to provide a more realistic model for the shape of discocytes in the thin biconcave-disc form with a toroidal rim. The bun model is also more rugged than the Cassini equation. Using the actual cell dimensions for calculations, the numerical results among these calculated cell volumes revealed large and significant differences with respect to the Bun-model of +32.09%, +8.95%, and −8.45% for prolate-spheroid, Cassini's equation, and oblate-spheroid, respectively. These large volume deviations shift the magnitude of the sharp peak in dielectrophoretic velocity spectra to lower values with differences of +189.28%, +7.66%, and −9.49%, respectively. For traveling wave dielectrophoresis, similar results were found for the sharp peak of +145.76%, +7.71%, and −9.50%, respectively. The suitability of the Bun-model was verified by curve-fitting of the cell velocity spectra between experimental and theoretical curves, which gave the maximum discrepancies of less than ±10%.