Dielectrophoretic capture voltage spectrum for measurement of dielectric properties and separation of cancer cells

Abstract

In this paper, a new dielectrophoresis (DEP) method based on capture voltage spectrum is proposed for measuring dielectric properties of biological cells. The capture voltage spectrum can be obtained from the balance of dielectrophoretic force and Stokes drag force acting on the cell in a microfluidic device with fluid flow and strip electrodes. The method was demonstrated with the measurement of dielectric properties of human colon cancer cells . From the capture voltage spectrum, the real part of Clausius-Mossotti factor of HT-29 cells for different frequencies of applied electric field was obtained. The dielectric properties of cell interior and plasma membrane were then estimated by using single-shell dielectric model. The cell interior permittivity and conductivity were found to be insensitive to changes in the conductivity of the medium in which the cells are suspended, but the measured permittivity and conductivity of cell membrane were found to increase with the increase of medium conductivity. In addition, the measurement of capture voltage spectrum was found to be useful in providing the optimum operating conditions for separating HT-29 cells from other cells (such as red blood cells) using dielectrophoresis. V C 2012 American Institute of Physics. [http://dx

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

“…The DEP response of LNCaPs measured in this work is qualitatively similar to that of cancer cells measured by other research groups [33,36,54]. Figure 3(a) shows that in the tested frequency range, the trapping potential decreased with increasing frequency, i.e., less voltage was needed to trap cells at higher frequencies.…”

“…This binary separation mechanism makes DEP an attractive tool for cell separation, as DEP requires no biochemical treatment or labeling to achieve high capture efficiency and purity. However, to date, studies using DEP methods for CTC capture have only reported high capture performance for model cancer cell lines spiked in preprocessed blood with concentrations ranging from one cancer cell per 10 4 -10 6 blood cells [33,34,36,39,40,42,44]. The commercially licensed ApoStream ™ (ApoCell) system, which uses DEP-FFF, has reported capture efficiencies in the range of 50-80% for ovarian and breast cancer cell lines spiked in peripheral blood mononuclear cells (PBMCs) with concentrations as low as one cancer cell per 10 6 blood cells, but noted that efficiency decreased after running samples through the system multiple times to increase capture purity [35].…”

“…A majority of DEP cancer cell isolation techniques use model cancer cell lines spiked in buffer media or diluted blood; such techniques include DEP flowfield fractionation (DEP-FFF) [33][34][35][36], insulative and contactless DEP [37][38][39][40], and streamline separations using angled electrodes [41][42][43][44]. These studies separate cancer cells from other blood constituents based on their differences in DEP response in a specific applied frequency range.…”

Recent advances in microfluidic techniques for single-cell biophysical characterization

“…However, since the spectra are not from the measurements of the same cells, only average electrical properties of a cell population can be obtained. [109][110][111] More details on DEP and ROT models can be found in other reviews. 9,112 The most popular ROT setup uses four electrodes connected to sine waves in phase quadrature.…”

Microfluidic dielectrophoretic sorter using gel vertical electrodes

“…[1][2][3][4][5][6][7][8] Dielectrophoresis (DEP) is a common microfluidic technique which accomplishes this using electric field gradients. [9][10][11][12][13][14][15][16][17] This has been applied to various biomedical assays, such as rare cell detection, protein separation, and enrichment of a cell population of interest. [18][19][20][21][22][23][24][25] Traditionally, the electric field gradient necessary for DEP is formed in a microchannel using two-dimensional electrodes strategically patterned on the device substrate.…”