Passive electrical properties of the membrane and cytoplasm of cultured rat basophil leukemia cells. I. Dielectric behavior of cell suspensions in 0.01-500 MHz and its simulation with a single-shell model.

摘要: Frequency dependence of relative permittivity (dielectric constant) and conductivity, or the 'dielectric dispersion', cultured cells (RBL-1 line) in suspension was measured using a fast impedance analyzer system capable scanning 92 frequency points over 10 kHz-500 MHz range within 80 s. Examination resulting dispersion curves an improved reliability revealed that dispersions consisted at least two separate components. The low-frequency component (dispersion 1) had increment (delta epsilon) 10(3)-10(4) characteristic (fc) several hundred kHz; for high-frequency 2), delta epsilon smaller by factor 10(2) fc = 10-30 MHz. Increments both components increased with volume fraction cell suspension, while did not change appreciably as long conductivity suspending medium fixed. By fitting model shelled spheres (the 'single-shell' model) to data 1, dielectric capacity plasma membrane phase (Cm) estimated be approx. 1.4 microF/cm2 isotonic medium. However, simulation this particular shell failed reproduce entire profile leaving sizable discrepancy between theory experiment especially frequencies above 1 where 2 took place. This could filled up even taking into consideration either effect size distribution actually determined possible heterogeneity intracellular conductivity. present strongly indicate need more penetrating effectively accounts behavior 2.