The Removal of Human Breast Cancer Cells from Hematopoietic CD34⁺Stem Cells by Dielectrophoretic Field-Flow-Fractionation

Abstract

Dielectrophoretic field-flow-fractionation (DEP-FFF) was used to purge human breast cancer MDA-435 cells from hematopoietic CD34+ stem cells. An array of interdigitated microelectrodes lining the bottom surface of a thin chamber was used to generate dielectrophoretic forces that levitated the cell mixture in a fluid flow profile. CD34+ stem cells were levitated higher, were carried faster by the fluid flow, and exited the separation chamber earlier than the cancer cells. Using on-line flow cytometry, efficient separation of the cell mixture was observed in less than 12 min, and CD34+ stem cell fractions with a purity >99.2% were obtained. The method of DEP-FFF is potentially applicable to many biomedical cell separation problems, including microfluidic-scale diagnosis and preparative-scale purification of cell subpopulations.

Characterization of a hybrid dielectrophoresis and immunocapture microfluidic system for cancer cell capture

“…This trend suggests that the DEP response of the cells was stronger at higher frequencies, as confirmed in the proportionate DEP response data shown in Figure 3 The curve fits for ℜ(f̃C M ) in Figure 3(b) were calculated by modeling the LNCaP cell as a single-shelled dielectric sphere with a frequency-dependent DEP response primarily dictated by a specific membrane capacitance, C membrane [52]. In the high-conductivity cases, the pDEP response and crossover frequency regions were fit well; the magnitude and frequency dependence, as well as the fit value for C membrane , were similar to those previously reported for other cancer cells [54][55][56]. Yang et al reported on DEP separation of LNCaPs from colorectal cancer cells, but used a higher conductivity media (σ m = 300 mS/m) at which LNCaPs experienced nDEP even in the MHz range [44].…”

“…We found that for the applied electric fields that were tested (10 kHz to 10 MHz, up to 10 V pp ), the cells exhibited no measurable pDEP response in both sugar solutions and PBS with σ m > 100 mS/m. Therefore, we minimally diluted both buffer solutions to 70 mS/m, which is two to seven times higher than conductivities used in the majority of DEP cancer cell capture studies [33,[53][54][55]. We obtained similar DEP characterization data for the highconductivity sugar solution and diluted PBS solution, which suggests that diluted PBS is an appropriate substitute for the isotonic sugar solution.…”

Capacitance cytometry: Measuring biological cells one by one

“…T he electrical properties of biological cells are of great interest, as they can provide opportunities to develop novel, rapid assays for disease (1,2) and integrated hybrid chips for electronics (3)(4)(5)(6)(7). Previous electrical studies of cells have focused on external macroscopic properties, such as cell membrane responses or volume, and have reflected primarily those of large ensembles of cells (8,9).…”

New trends in non-invasive prenatal diagnosis: Applications of dielectrophoresis-based Lab-on-a-chip platforms to the identification and manipulation of rare cells (Review)

“…84) have firmly demonstrated that human cell populations of different histotype and differentiation stage are able to be isolated using DEP-based devices. These features propose Lab-on-a-chip platforms for diagnostic applications, cell separation and characterization in the field of non-invasive prenatal diagnosis (88)(89)(90)(91)(92)(93)(94)(95)(96)(97)(98).…”