Theoretical and experimental investigations of the interdependence of the dielectric, dielectrophoretic and electrorotational behaviour of colloidal particles

Wang, Xiaobo; Huang, Ying; Hölzel, Ralph; Burt, Julian P.H.; Pethig, Ronald

doi:10.1088/0022-3727/26/2/021

Cited by 112 publications

(83 citation statements)

References 29 publications

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“…9 For many biomedical applications, this dielectric difference in combination with nonuniform electric fields can be used to translate cells ͑dielectrophoresis͒, or with uniform time-varying fields to rotate cells ͑electrorotation͒. 10 Recently, dielectrophoretic forces have been enhanced with improved control using multi-insulating blocks for manipulating polystyrene microspheres. 11 Parikesit and co-workers 12 recently used insulating structures to enhance dielectrophoretic signals for size-dependent sorting of continuously flowing DNA molecules.…”

Section: Introductionmentioning

confidence: 99%

Microfluidic electromanipulation with capacitive detection for the mechanical analysis of cells

et al. 2008

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The mechanical behavior of cells offers insight into many aspects of their properties. We propose an approach to the mechanical analysis of cells that uses a combination of electromanipulation for stimulus and capacitance for sensing. To demonstrate this approach, polystyrene spheres and yeast cells flowing in a 25 m ϫ 100 m microfluidic channel were detected by a perpendicular pair of gold thin film electrodes in the channel, spaced 25 m apart. The presence of cells was detected by capacitance changes between the gold electrodes. The capacitance sensor was a resonant coaxial radio frequency cavity ͑2.3 GHz͒ coupled to the electrodes. The presence of yeast cells ͑Saccharomyces cerevisiae͒ and polystyrene spheres resulted in capacitance changes of approximately 10 and 100 attoFarad ͑aF͒, respectively, with an achieved capacitance resolution of less than 2 aF in a 30 Hz bandwidth. The resolution is better than previously reported in the literature, and the capacitance changes are in agreement with values estimated by finite element simulations. Yeast cells were trapped using dielectrophoretic forces by applying a 3 V signal at 1 MHz between the electrodes. After trapping, the cells were displaced using amplitude and frequency modulated voltages to produce modulated dielectrophoretic forces. Repetitive displacement and relaxation of these cells was observed using both capacitance and video microscopy.

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Section: Introductionmentioning

confidence: 99%

Microfluidic electromanipulation with capacitive detection for the mechanical analysis of cells

et al. 2008

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“…At lowest order in the applied field the dielectrophoretic force on a particle is proportional to the in-phase part of the induced dipole moment and to the gradient of the timeaveraged applied electric field, whereas the electrorotational torque is proportional to the out-of-phase part of the induced dipole moment and to the time-averaged applied electric field [7][8][9][10]. Since at this order the induced dipole is itself proportional to the applied field, controlling the square and the gradient of the square of the electric field are critical issues in the design of the electrodes that generate the rotating fields in an ER chamber [1,[11][12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Electromechanical effects on multilayered cells in nonuniform rotating fields

Sebastián

Muñoz²,

Martı́nez³

et al. 2011

Phys. Rev. E

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We use the Maxwell stress tensor to calculate the dielectrophoretic force and electrorotational torque acting on a realistic four-shelled model of the yeast Saccharomyces cerevisiae in a nonuniform rotating electric field generated by four coplanar square electrodes. The comparison of these results with numerical calculations of the dipolar and quadrupolar contributions obtained from an integral equation for the polarization charge density shows the effect of the quadrupole contribution in the proximity of the electrode plane. We also show that under typical experimental conditions the substitution of the multilayered cell by an equivalent cell with homogeneous permittivity underestimates the quadrupole contribution to the force and torque by 1 order of magnitude.

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“…The general driving force of the particle rotation is a phase difference between the electric field-induced polarization and the external rotating field. This gives rise to a torque acting on the particle that depends on the frequency of the applied field, the geometry, and dielectic properties of the particle (18,(26)(27)(28) (10,18,(27)(28)(29)(30)(31)(32)(33).…”

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confidence: 99%

“…One hundred microliters of this suspension was sealed into the rotation chamber and measured immediately after the settling of the cells. Every point of the rotation curve represented measurements of [20][21][22][23][24][25][26][27][28][29][30] cells. The ROT spectrum consisted of 15 measuring points and was usually completed within 20-30 min.…”

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confidence: 99%

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Dielectric changes in membrane properties and cell interiors of human mesothelial cells in vitro after crocidolite asbestos exposure.

Dopp

Jonas

Nebe

et al. 2000

Environ Health Perspect

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Asbestos induces cytogenetic and genotoxic effects in cultured cell lines in vitro. For fiuther investigations of the fiber-induced cellular changes, electrorotation (ROT) measurements can be used to determine early changes of surface properties and dielectric cellular changes. In the present study, human mesothelial cells (HMC) were exosed to nontoxic concentrations of crocidolite asbestos (1 pg/cm2) for 12, 24, 30, 50, and 72 hr, and were investigated for changes in dielectric properties, morphologic and biochemical changs using ROT measurements, electron microscopy, and flow cytometry, respectively. The results of ROT measurements raled slighdy increased internal conductivity and decreased membrane conductance ofHMC during the first 12 hr of exposure to crocidolite. This may be due to functional changes of ion channels of the cellular membrane. However, after exposures of . 30 hr, reduced internal conductivity and increasd membrane conductance of HMC occurred. These effects may be caused by permeabilization ofthe cell membrane and the leakage of ions into the surrounding medium. The membrane capacitance of HMC is always decreased during exposure of cells to crocidolite fibers. This decreased membrane capacitance may result from the observed reduction in the number of microvilli and from the shrnkage of cells as observed by electron microscopy and flow cytometry. Changes in composition of the plasma membrane were also observed after the labeling of phosphatidylserines (PS) on the cell surface. These observed changes can be related to apoptotic events. Whereas during the first 50 hr of exposure only a small number of HMC with increased exposure of PS on the cell surface was detected by flow cytometry, the dielectric properties of HMC showed marked changes during this time. Our results show that surface property changes of the cellular membrane of HMC as well as interior dielectric change occur after the exposure ofcells to crocidolite fibers. The observed changes are discussed in terms of complex combined cellular effects after amphibole asbestos exposure. Key words apoptosis, crocidolite, electron microscopy, electrorotation, flow cytometry, phosphatidylserine, plasma membrane. Environ Heath Perspec 108: 153-158 (2000 (5). The investigation of the effects of chemicals and environmental factors on the dielectric behavior of cells is increasingly becoming an area of scientific interest. ROT was used to characterize alterations of dielectric properties of lymphocytes (6), cell membrane changes after viral infection and transformation (7-9) as well as platelet activation (10), biofilms (11) and microbial contamination (12), the effect of chemicals on cells (13), cytoplasmatic dielectric properties (14), different cellular compartments of individual cells (15), and mobile charges on membranes (16). Rotation at physiologic ionic strength (17) and low-frequency ROT of erythrocytes (18) have also been studied. All of these ROT studies were performed using conventional microscopes for rotation measurements. Cell rotat...

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Theoretical and experimental investigations of the interdependence of the dielectric, dielectrophoretic and electrorotational behaviour of colloidal particles

Cited by 112 publications

References 29 publications

Microfluidic electromanipulation with capacitive detection for the mechanical analysis of cells

Microfluidic electromanipulation with capacitive detection for the mechanical analysis of cells

Electromechanical effects on multilayered cells in nonuniform rotating fields

Dielectric changes in membrane properties and cell interiors of human mesothelial cells in vitro after crocidolite asbestos exposure.

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