Analysis of biological suspensions by dielectric, impedance, and AC electrokinetic methods

Analysis of biological cell suspensions by dielectric, impedance, and AC electrokinetic methods 

A cell with a typical radius ofR = 2 pm is contained in a 5-10 nm thick phospholipid bilayer membrane. Each cell membrane has hydrophobic external and hydrophilic internal layers. The cell can control its cytoplasm composition by controlling its membrane permeability. In a cell membrane there are 

FIGURE 11-1 Multilayered shells A. spherical particle with one concentric shell B. equivalent homogeneous particle as long as the physical scale of the nonuniformity of the imposed field is much larger than the particle radius R, the external field of the equivalent particle is indistinguishable from that of the heterogeneous particle 

With further frequency increase, the cytoplasm can produce dispersion due to a switch from resistive to capacitive conduction in kHz-low MHz range (P3), which can be detected if the characteristic frequency of this relaxation is between pi and pz [4], However, the presence of a significant cytoplasm-capacitive component is often disregarded, and the total cytoplasm imped- 

FICURE11-2 Dielectric relaxations in bulk solution suspensions of blood cells 

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