DEP-FFF elution profiles for (A) SF295 human glioblastoma cells and (B) MOLT4 human acute lymphoblastic leukemia cells demonstrating the behavior of NCI-60 cells having large differences in their density, dielectric, and hydrodynamic lift properties. The elution profiles for 15 kHz DEP reflect predominantly cell density differences; those for no DEP (sedFFF) reflect cell density and hydrodynamic lift effects; and those using a DEP frequency sweep reflect the combination of sedimentation, hydrodynamic lift and DEP crossover frequency effects.
Densities of the NCI-60 cell types deduced from DEP-FFF analysis of the cells and shown in ascending order. The thickness of each scale bar represents the number of cells at a given density relative to the mode, which has maximum thickness, based on skew-normal distributions. The blue line shows the density of Histopaque 1077 and LSM at 1077 kg/m3.
DEP crossover frequencies of the NCI-60 cell types and normal peripheral blood cells deduced from DEP-FFF analysis shown in ascending order at a suspension conductivity of 30 mS/m. The thickness of each scale bar represents the number of cells at a given crossover frequency relative to the mode, which has maximum thickness, based on skew-normal distributions. The blue line at 65 kHz shows a possible choice for a DEP-FFF operating frequency that should be able to isolate NCI-60 cell types, except leukemia lines, from normal blood cells.
Range of DEP crossover frequencies ±1 standard deviation of the NCI-60 cell types and normal peripheral blood cells deduced from DEP-FFF analysis at a suspension conductivity of 30 mS/m by tissue origin. The blue line at 65 kHz shows a possible choice for a DEP-FFF operating frequency that would isolate essentially all NCI-60 cell types except leukemia lines from blood.
Batch-mode DEP-FFF elution profiles for two mixtures of cancer cells with normal peripheral blood mononuclear cells: (A) Normal PBMNs + MDA-MB-231 breast tumor cells run at a DEP operating frequency of 65 kHz; (B) Mormal PBMNs + HL-60 promyelocytic leukemia cells run at 80 kHz. Different colors denote cells of differing size ranges. Note that the elution times for the cancer cells have a weak dependency on cell size because their DEP crossover frequencies dominate their elution behaviors. The scale at top shows the height at which the cells travelled through the DEP chamber as deduced from their elution times in the Poiseiulle flow profile. The cancer cells were tracked by prelabelling them with green-fluorescent calcein-AM viable cell stain (L-3224, Molecular Probes, Life Technologies).
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