Frequency sweep rate dependence on the dielectrophoretic response of polystyrene beads and red blood cells

Adams, Tayloria N.G.; Leonard, Kaela M.; Minerick, Adrienne R.

doi:10.1063/1.4833095

Cited by 27 publications

(36 citation statements)

References 35 publications

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“…This result suggests the polarization is not dominated by surface ion alignments (conductivity dominated). Above roughly 1 MHz, these observations are consistent with dielectric permittivity ( ε ) polarization mechanisms, which begin to dominate conductivity ( σ ) polarization mechanisms on DEP force magnitude .…”

Section: Resultssupporting

confidence: 70%

“…Theory predicts that core‐shell microparticles and cells both gradually transition from nDEP at lower frequencies to pDEP at intermediate frequencies and back to nDEP at higher frequencies, thus displaying two crossover frequencies . Figure illustrates Clausius–Mossotti predictions of the particle DEP behavior for a PLL shell permittivity of 90 and conductivity of 0.1 S/m.…”

Section: Resultsmentioning

confidence: 98%

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Size and medium conductivity dependence on dielectrophoretic behaviors of gas core poly‐l‐lysine shell nanoparticles

Yang

Ostafin

et al. 2015

Electrophoresis

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Dynamic (dis)assembly of biocompatible nanoparticles into 3D, packed structures would benefit drug delivery, films, and diagnostics. Dielectrophoretic (DEP) microdevices can rapidly assemble and manipulate polarizable particles within nonuniform electric fields. DEP has primarily discerned micrometer particles since nanoparticles experience smaller forces. This work examines conductivity and size DEP dependencies of previously unexplored spherical core-shell nanoparticle (CSnp) into 3D particle assemblies. Poly-L-lysine shell material was custom synthesized around a gas core to form CSnps. DEP frequencies from 1 kHz to 80 MHz at fixed 5 volts peak-to-peak and medium conductivities of 10(-5) and 10(-3) S/m were tested. DEP responses of ∼220 and ∼400 nm poly-L-lysine CSnps were quantified via video intensity densitometry at the microdevice's quadrapole electrode center for negative DEP (nDEP) and adjacent to electrodes for positive DEP. Intensity densitometry was then translated into a relative DEP response curve. An unusual nDEP peak occurred at ∼57 MHz with 25-80 times greater apparent nDEP force. All electrical circuit components were then impedance matched, which changed the observed response to weak positive DEP at low frequencies and consistently weak nDEP from ∼100 kHz to 80 MHz. This impedance-matched behavior agrees with conventional Clausius-Mossotti DEP signatures taking into account the gas core's contributions to the polarization mechanisms. This work describes a potential pitfall when conducting DEP at higher frequencies in microdevices and concurrently demonstrates nDEP behavior for a chemically and structurally distinct particle system. This work provides insight into organic shell material properties in nanostructures and strategies to facilitate dynamic nanoparticle assemblies.

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Section: Resultssupporting

confidence: 70%

Section: Resultsmentioning

confidence: 98%

Size and medium conductivity dependence on dielectrophoretic behaviors of gas core poly‐l‐lysine shell nanoparticles

Yang

Ostafin

et al. 2015

Electrophoresis

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“…This dependency was most discernable near the hMSCs frequency transition region from nDEP to pDEP and the f xo value, both were encompassed in the range of 0.61 and 1.4 MHz. Maxwell-Wagner interfacial polarization mechanisms dominate in the frequency range from 0.010 MHz to 10 MHz in the b-dispersion region, 40 such that an observed f xo is influenced by the ionic interactions of the hMSCs membrane with the surrounding medium. As the frequency increases in the MHz range, this interfacial polarization transitions to being dominated by the membrane permittivity, which was more consistent with the optimized model parameters in Table I.…”

Section: Resultsmentioning

confidence: 99%

“…A cell's complex permittivity is frequency dependent and characterized by the a, b, and c dielectric dispersion regions (x a < x b < x c ). 40 At radio frequencies (b-region), 0.010-10 MHz, the dielectric dispersion of cells are affected by their membrane; high frequencies penetrate a cells surface and interogates the internal structure. Therefore, a plethora of information can be obtained about a cell population in the b-region; many researchers complete their experiments within this frequency range.…”

Section: Introductionmentioning

confidence: 99%

Characterizing the dielectric properties of human mesenchymal stem cells and the effects of charged elastin-like polypeptide copolymer treatment

et al. 2014

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HUMAN MESENCHYMAL STEM CELLS (HMSCS) HAVE THREE KEY PROPERTIES THAT MAKE THEM DESIRABLE FOR STEM CELL THERAPEUTICS: differentiation capacity, trophic activity, and ability to self-renew. However, current separation techniques are inefficient, time consuming, expensive, and, in some cases, alter hMSCs cellular function and viability. Dielectrophoresis (DEP) is a technique that uses alternating current electric fields to spatially separate biological cells based on the dielectric properties of their membrane and cytoplasm. This work implements the first steps toward the development of a continuous cell sorting microfluidic device by characterizing native hMSCs dielectric signatures and comparing them to hMSCs morphologically standardized with a polymer. A quadrapole Ti-Au electrode microdevice was used to observe hMSC DEP behaviors, and quantify frequency spectra and cross-over frequency of hMSCs from 0.010-35 MHz in dextrose buffer solutions (0.030 S/m and 0.10 S/m). This combined approach included a systematic parametric study to fit a core-shell model to the DEP spectra over the entire tested frequency range, adding robustness to the analysis technique. The membrane capacitance and permittivity were found to be 2.2 pF and 2.0 in 0.030 S/m and 4.5 pF and 4.1 in 0.10 S/m, respectively. Elastin-like polypeptide (ELP-) polyethyleneimine (PEI) copolymer was used to control hMSCs morphology to spheroidal cells and aggregates. Results demonstrated that ELP-PEI treatment controlled hMSCs morphology, increased experiment reproducibility, and concurrently increased hMSCs membrane permittivity to shift the cross-over frequency above 35 MHz. Therefore, ELP-PEI treatment may serve as a tool for the eventual determination of biosurface marker-dependent DEP signatures and hMSCs purification.

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“…To increase accessibility and ease of blood analysis, research has focused on dielectrophoretic manipulation of red blood cells (RBCs) to create medical diagnostic devices that can either (i) discern undesirable cells (bacteria, circulating tumor cells) from blood or (ii) measure properties of the RBCs themselves. EK responses to RBC membrane chemistry, cell age, treatment, and media conditions have been systematically cataloged by our group . Different DEP responses are observed for cells with differing ABO‐Rh blood type ; ABO surface antigens impact conductivity polarizations while the transmembrane Rh factor impacts permittivity polarizations.…”

Section: Introductionmentioning

confidence: 99%

Theoretical and experimental examination of particle–particle interaction effects on induced dipole moments and dielectrophoretic responses of multiple particle chains

2014

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Dielectrophoresis (DEP), an electrokinetic phenomenon based on particle polarizations in nonuniform electric fields, is increasingly employed for particle and cell characterizations and manipulations in microdevices. However, particle number densities are rarely varied and particle-particle interactions are largely overlooked, but both affect particle's effective polarizations by changing the local electric field, which directly impacts particle assembly into chains. This work examines theoretical and experimental particle-particle interactions and dielectrophoretic responses in nonuniform electric fields, then presents individual and chain velocities of spherical polystyrene microparticles and red blood cells (RBCs) under DEP forces in a modified quadruple electrode microdevice. Velocities are independently compared between 1, 2, 3, and 4 polystyrene beads and RBCs assembled into chains aligned with the electric field. Simulations compared induced dipole moments for particles experiencing the same (single point) and changing (multiple points) electric fields. Experiments and simulations are compared by plotting DEP velocities versus applied signal frequency from 1 kHz to 80 MHz. Simulations indicate differences in the DEP force exerted on each particle according to chain position. Simulations and experiments show excellent qualitative agreement; chains with more particles experienced a decrease in the DEP response for both polystyrene beads and RBCs. These results advance understanding of the extent that induced dipole polarizations with multiple particle chains affect observed behaviors in electrokinetic cellular diagnostic systems.

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Frequency sweep rate dependence on the dielectrophoretic response of polystyrene beads and red blood cells

Cited by 27 publications

References 35 publications

Size and medium conductivity dependence on dielectrophoretic behaviors of gas core poly‐l‐lysine shell nanoparticles

Size and medium conductivity dependence on dielectrophoretic behaviors of gas core poly‐l‐lysine shell nanoparticles

Characterizing the dielectric properties of human mesenchymal stem cells and the effects of charged elastin-like polypeptide copolymer treatment

Theoretical and experimental examination of particle–particle interaction effects on induced dipole moments and dielectrophoretic responses of multiple particle chains

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