Reversible Assembly of Colloidal Particles Using Low Frequency Pulsed DC Electric Fields

2016 ◽  
Keyword(s):  
Electric Fields ◽  
Colloidal Particles ◽  
Low Frequency ◽  
Pulsed Dc ◽  
Dc Electric Fields

Pulsed DC electric fields couple to natural NAD(P)H oscillations in HT-1080 fibrosarcoma cells

2001 ◽  
Vol 114 (8) ◽  
pp. 1515-1520 ◽  
Author(s):  
A.J. Rosenspire ◽  
A.L. Kindzelskii ◽  
H.R. Petty
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Cell Function ◽  
Low Frequency ◽  
Reactive Oxygen Metabolites ◽  
Pulsed Dc ◽  
Fibrosarcoma Cells ◽  
Chemotactic Factors ◽  
Oxygen Metabolites ◽  
Dc Electric Fields

Previously, we have demonstrated that NAD(P)H levels in neutrophils and macrophages are oscillatory. We have also found that weak ultra low frequency AC or pulsed DC electric fields can resonate with, and increase the amplitude of, NAD(P)H oscillations in these cells. For these cells, increased NAD(P)H amplitudes directly signal changes in behavior in the absence of cytokines or chemotactic factors. Here, we have studied the effect of pulsed DC electric fields on HT-1080 fibrosarcoma cells. As in neutrophils and macrophages, NAD(P)H levels oscillate. We find that weak (~10(-)(5) V/m), but properly phased DC (pulsed) electric fields, resonate with NAD(P)H oscillations in polarized and migratory, but not spherical, HT-1080 cells. In this instance, electric field resonance signals an increase in HT-1080 pericellular proteolytic activity. Electric field resonance also triggers an immediate increase in the production of reactive oxygen metabolites. Under resonance conditions, we find evidence of DNA damage in HT-1080 cells in as little as 5 minutes. Thus the ability of external electric fields to effect cell function and physiology by acting on NAD(P)H oscillations is not restricted to cells of the hematopoietic lineage, but may be a universal property of many, if not all polarized and migratory eukaryotic cells.

Convergence effect of droplet coalescence under AC and pulsed DC electric fields

2021 ◽  
pp. 103776
Author(s):  
Xin Huang ◽  
Limin He ◽  
Xiaoming Luo ◽  
Ke Xu ◽  
Yuling Lü ◽  
...  
Keyword(s):  
Electric Fields ◽  
Droplet Coalescence ◽  
Pulsed Dc ◽  
Dc Electric Fields

Characterization of interactive force acting on colloidal particles near an electrode in presence of a high-frequency (>10 kHz) AC electric field using particle diffusometry

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Kshitiz Gupta ◽  
Dong Hoon Lee ◽  
Steven T. Wereley ◽  
Stuart J. Williams
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Particle Motion ◽  
Electrode Surface ◽  
High Frequency ◽  
Colloidal Particles ◽  
Low Frequency ◽  
Double Layers ◽  
Average Height ◽  
Ac Electric Field

Colloidal particles like polystyrene beads and metallic micro and nanoparticles are known to assemble in crystal-like structures near an electrode surface under both DC and AC electric fields. Various studies have shown that this self-assembly is governed by a balance between an attractive electrohydrodynamic (EHD) force and an induced dipole-dipole repulsion (Trau et al., 1997). The EHD force originates from electrolyte flow caused by interaction between the electric field and the polarized double layers of both the particles and the electrode surface. The particles are found to either aggregate or repel from each other on application of electric field depending on the mobility of the ions in the electrolyte (Woehl et al., 2014). The particle motion in the electrode plane is studied well under various conditions however, not as many references are available in the literature that discuss the effects of the AC electric field on their out-of-plane motion, especially at high frequencies (>10 kHz). Haughey and Earnshaw (1998), and Fagan et al. (2005) have studied the particle motion perpendicular to the electrode plane and their average height from the electrode mostly in presence of DC or low frequency AC (<1 kHz) electric field. However, these studies do not provide enough insight towards the effects of high frequency (>10 kHz) electric field on the particles’ motion perpendicular to the electrode plane.  

Electro-coalescence of two charged droplets under constant and pulsed DC electric fields

2016 ◽  
Vol 98 ◽  
pp. 10-16 ◽  
Author(s):  
Bing-Bing Wang ◽  
Xiao-Dong Wang ◽  
Tian-Hu Wang ◽  
Gui Lu ◽  
Wei-Mon Yan
Keyword(s):  
Electric Fields ◽  
Charged Droplets ◽  
Pulsed Dc ◽  
Dc Electric Fields

Electro-optic observations of electrodynamic band formation in colloidal suspensions

1990 ◽  
Vol 427 (1873) ◽  
pp. 321-330 ◽  
Keyword(s):  
Electric Fields ◽  
Colloidal Particles ◽  
Local Density ◽  
Low Frequency ◽  
Colloidal Suspensions ◽  
Field Vector ◽  
High Concentration ◽  
Band Formation ◽  
Alternating Electric Fields ◽  
Field Lines

In static and low-frequency electric fields, colloidal particles in suspension tend to associate into ‘strings’ or ‘pearl chains’ along the field lines. A phenomenon has been observed in which, under long duration alternating electric fields, colloidal particles in aqueous or conducting media exhibit an electrodynamic instability in which they gather into high concentration ‘bands’ which run essentially perpendicular to the applied field vector. A detailed study is catalogued herein for aqueous suspensions of the discotic mineral kaolinite. A theory has been developed, which embraces the ‘pearl chain’ and ‘band’ formations, demonstrating that one can be formed from the other with increasing frequency and field strength and illustrating the dependence of band formation on electrophoretic mobility as observed in related electro-optical experiments. The value of the phenomenon as a mechanism for concentrating dispersed colloidal particles into regions of very high local density is apparent.

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