Dielectric characterization of bacterial cells using dielectrophoresis

Sanchis, Adrian Garrido; Brown, Alexandra; Sancho, M.; Martı́nez, G; Sebastián, J.L.; Muñoz, S.; Miranda, J. M.

doi:10.1002/bem.20317

Cited by 91 publications

(83 citation statements)

References 31 publications

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“…The results from the present work and results based on Goater's work agree reasonably well. Table I shows the dielectric parameters of the cell compartments obtained in the present study compared with the results obtained for other Gram positive (S. aureus) and Gram negative (E. coli) bacteria from Sanchis et al 10 and Johari et al 7 Gram positive bacteria such as S. aureus has a significantly higher cytoplasm conductivity compared to the Cryptosporidium, which could be explained in line with the known fact that Gram positive bacteria have a higher K þ content in their cytoplasm. As the two species have nearly the same size (1-2 lm cell radius), the difference in dielectric properties of the above two species may be utilized as a key parameter for separation of the two species on-chip.…”

Section: -10mentioning

confidence: 81%

“…A simple experimental setup using sharp needle electrodes immersed in a static suspension was employed to interpret the number of collected cells as proportional to dielectric polarizability values. Later, Sanchis et al 10 improved on the above two methods by (1) assuming a rod shape model for E. coli bacteria and (2) using a microelectrode chamber containing interdigitated electrodes through which the cell suspension circulates and a direct cell counting method by an image analysis system. Dielectric parameters of the cell compartments of E. coli and Staphylococcus aureus bacteria were determined using the above approach.…”

Section: B)mentioning

confidence: 99%

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Characterization and separation of Cryptosporidium and Giardia cells using on-chip dielectrophoresis

et al. 2012

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Dielectrophoresis (DEP) has been shown to have significant potential for the characterization of cells and could become an efficient tool for rapid identification and assessment of microorganisms. The present work is focused on the trapping, characterization, and separation of two species of Cryptosporidium (C. parvum and C. muris) and Giardia lambia (G. lambia) using a microfluidic experimental setup. Cryptosporidium oocysts, which are 2-4 lm in size and nearly spherical in shape, are used for the preliminary stage of prototype development and testing. G. lambia cysts are 8-12 lm in size. In order to facilitate effective trapping, simulations were performed to study the effects of buffer conductivity and applied voltage on the flow and cell transport inside the DEP chip. Microscopic experiments were performed using the fabricated device and the real part of Clausius-Mossotti factor of the cells was estimated from critical voltages for particle trapping at the electrodes under steady fluid flow. The dielectric properties of the cell compartments (cytoplasm and membrane) were calculated based on a single shell model of the cells. The separation of C. muris and G. lambia is achieved successfully at a frequency of 10 MHz and a voltage of 3 Vpp (peak to peak voltage).

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Section: -10mentioning

confidence: 81%

Section: B)mentioning

confidence: 99%

Characterization and separation of Cryptosporidium and Giardia cells using on-chip dielectrophoresis

et al. 2012

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“…20 To obtain an estimation of the Clausius-Massotti factor (f CM ), the electrical parameters of S. aureus bacteria and the surrounding DI water medium shown in Table I were used. 12 Using Eqs. (2) and (3), real and imaginary values of f CM were estimated using Matlab R2014a, as shown in Figure 5(d).…”

Section: A Numerical Modelingmentioning

confidence: 99%

“…iDEP devices have been employed in the past to characterize particles including bacteria, viruses, cells, and beads. [10][11][12][13] Previously, three dimensional insulator-based dielectrophoresis (3D iDEP) devices have been used to increase sensitivity of iDEP devices. 14 Use of 3D insulating features has been shown to increase electric field gradient and the DEP force acting on particles.…”

Section: Introductionmentioning

confidence: 99%

Three dimensional passivated-electrode insulator-based dielectrophoresis

et al. 2015

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In this study, a 3D passivated-electrode, insulator-based dielectrophoresis microchip (3D pDEP) is presented. This technology combines the benefits of electrodebased DEP, insulator-based DEP, and three dimensional insulating features with the goal of improving trapping efficiency of biological species at low applied signals and fostering wide frequency range operation of the microfluidic device. The 3D pDEP chips were fabricated by making 3D structures in silicon using reactive ion etching. The reusable electrodes are deposited on second glass substrate and then aligned to the microfluidic channel to capacitively couple the electric signal through a 100 lm glass slide. The 3D insulating structures generate high electric field gradients, which ultimately increases the DEP force. To demonstrate the capabilities of 3D pDEP, Staphylococcus aureus was trapped from water samples under varied electrical environments. Trapping efficiencies of 100% were obtained at flow rates as high as 350 ll/h and 70% at flow rates as high as 750 ll/h. Additionally, for live bacteria samples, 100% trapping was demonstrated over a wide frequency range from 50 to 400 kHz with an amplitude applied signal of 200 Vpp. 20% trapping of bacteria was observed at applied voltages as low as 50 Vpp. We demonstrate selective trapping of live and dead bacteria at frequencies ranging from 30 to 60 kHz at 400 Vpp with over 90% of the live bacteria trapped while most of the dead bacteria escape. V C 2015 AIP Publishing LLC.

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“…The dielectric properties of various cells have been estimated by measuring the DEP velocity spectrum, 3 cross-over frequencies for different medium conductivity, 12,24,25 or collection spectra. 26,27 From the collection of the dielectric properties obtained by above techniques, the typical value of cytoplasm relative permittivity and conductivity have been found in the range of 50-150 and 0.1-1.3 S/m, respectively; and the relative permittivity and conductivity of cell membrane were estimated to be around 2-15 and 10…”

Section: Introductionmentioning

confidence: 99%

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

Wu¹,

Yung²,

Lim³

2012

Biomicrofluidics

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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

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Dielectric characterization of bacterial cells using dielectrophoresis

Cited by 91 publications

References 31 publications

Characterization and separation of Cryptosporidium and Giardia cells using on-chip dielectrophoresis

Characterization and separation of Cryptosporidium and Giardia cells using on-chip dielectrophoresis

Three dimensional passivated-electrode insulator-based dielectrophoresis

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

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