LOW-FREQUENCY ELECTROROTATION OF FIXED RED-BLOOD-CELLS

Electrorotation of fixed red blood cells has been investigated in the frequency range between 16 Hz and 30 MHz. The rotation was studied as a function of electrolyte conductivity and surface charge density. Bet ween 16 Hz and 1 kHz, fixed red blood cells undergo cofield rotation. The maximum of cofield rotation occurs between 30 and 70 Hz. The posit ion of the maximum depends weakly on the bulk electrolyte conductivity and surface charge density. Below 3.5 mS/m, the cofield rotation peak is broadened and shifted to higher frequencies accompanied by a decre ase of the rotation speed. Surface charge reduction leads to a decreas e of the rotation speed in the low frequency range. These observations are consistent with the recently developed electroosmotic theory of l ow frequency electrorotation.