Fig. 6.
Cell biophysical properties may be derived from four independent measurements. A shows the displacement of cells through the DEP-FFF channel as a function of time under the influence of a low frequency DEP field. The frequency is set low enough that the cells attain maximum levitation and so their resulting velocities reflect their density. B the conventional sedimentation-FFF elution profile is measured with the DEP field off. C the DEP frequency is maintained far above the anticipated crossover frequency of the cells for a period Tint and then switched to the low frequency used for Run A. Cells travel at minimum velocity under the influence of hydrodynamic lift forces until the frequencies switch. D shows cell behavior during a 600 second sweep from 160 kHz to 15 kHz.