Proposal and experimental validation of the electrophoretic Coulter method for analyzing microparticles and biological cells

Takahashi, Nobutaka; Aki, Atsushi; Ukai, Tomofumi; Nakajima, Yoshio; Maekawa, Toru; Hanajiri, Tatsuro

doi:10.1016/j.snb.2010.09.056

Cited by 14 publications

(23 citation statements)

References 18 publications

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“…A total of 500 mg/L HA stock solution was prepared by dissolving HA in 0.l M NaOH solution, and then the final pH was adjusted to 7.0 with 0.1 M HCl solution. The actual sizes of the nano‐ZnO in medium were determined by DLS measurements (90Plus Particle Size Analyzer, Brookhaven Instruments Corporation; Takahashi et al, ).…”

Section: Methodsmentioning

confidence: 99%

The influence of humic acid on the toxicity of nano‐ZnO and Zn²⁺ to the Anabaena sp.

Tang

et al. 2014

Environmental Toxicology

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This study explored the effects of humic acid (HA) on the toxicity of ZnO nanoparticles (nano-ZnO) and Zn(2+) to Anabaena sp. Typical chlorophyll fluorescence parameters, including effective quantum yield, photosynthetic efficiency and maximal electron transport rate, were measured by a pulse-amplitude modulated fluorometer. Results showed that nano-ZnO and Zn(2+) could inhibit Anabaena sp. growth with the EC50 (concentration for 50% of maximal effect) of 0.74 ± 0.01 and 0.3 ± 0.01 mg/L, respectively. In the presence of 3.0 mg/L of HA, EC50 of nano-ZnO increased to 1.15 ± 0.04 mg/L and EC50 of Zn(2+) was still 0.3 ± 0.01 mg/L. Scanning electron microscopy observation revealed that HA prevented the adhesion of nano-ZnO on the algae cells due to the increased electrostatic repulsion. The generation of intracellular reactive oxygen species and cellular lipid peroxidation were significantly limited by HA. Nano-ZnO had more damage to the cell membrane than Zn(2+) did, which could be proven by the malondialdehyde content in Anabaena sp. cells. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 895-903, 2015.

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Section: Methodsmentioning

confidence: 99%

The influence of humic acid on the toxicity of nano‐ZnO and Zn²⁺ to the Anabaena sp.

Tang

et al. 2014

Environmental Toxicology

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“…and , respectively. The zeta potential values of PS particles and channel wall in 10 mM NaCl solution were set to be −33 and −54 mV, respectively . The dynamic viscosity,

η = 0.9 \times 10^{- 3} k g / (m \cdot s)

, and permittivity,

ɛ_{m} = 6.9 \times 10^{- 10} C / (v \cdot m)

for pure water at 25°C were also used.…”

Section: Methodsmentioning

confidence: 99%

Continuous manipulation and separation of particles using combined obstacle‐ and curvature‐induced direct current dielectrophoresis

et al. 2013

Electrophoresis

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G. (2013). Continuous manipulation and separation of particles using combined obstacle-and curvature-induced direct current dielectrophoresis. Electrophoresis, 34 (7), 952-960.Continuous manipulation and separation of particles using combined obstacle-and curvature-induced direct current dielectrophoresis AbstractThis paper presents a novel dielectrophoresis-based microfluidic device incorporating round hurdles within an S-shaped microchannel for continuous manipulation and separation of microparticles. Local nonuniform electric fields are generated due to the combined effects of obstacle and curvature, which in turn induce negative dielectrophoresis forces exerting on the particle that transport throughout the microchannel electrokinetically. Experiments were conducted to demonstrate the controlled trajectories of fix-sized (i.e. 10 or 15x μm) polystyrene particles, and size-dependent separation of 10 and 15 μm particles by adjusting the applied voltages at the inlet and outlets. Numerical simulations were also performed to predict the particle trajectories, which showed reasonable agreement with experimentally observed results. Compared to other microchannel designs that make use of either obstacle or curvature individually for inhomogeneous electric fields, the developed microchannel offers advantages such as improved controllability of particle motion, lower requirement of applied voltage, reduced fouling, and particle adhesion, etc. AbstractThis paper presents a novel dielectrophoresis (DEP)-based microfluidic device incorporating round hurdles within an S-shaped microchannel for continuous manipulation and separation of microparticles. Local nonuniform electric fields are generated due to the combined effects of obstacle and curvature, which in turn induce negative DEP forces exerting on the particle that transport throughout the microchannel electrokinetically. Experiments were conducted to demonstrate the controlled trajectories of fix-sized (i.e. 10 or 15 m) polystyrene (PS) particles, and size-dependent separation of 10 and 15 m particles by adjusting the applied voltages at the inlet and outlets. Numerical simulations were also performed to predict the particle trajectories, which showed reasonable agreement with experimentally observed results. Compared to other microchannel designs that make use of either obstacle or curvature individually for inhomogeneous electric fields, the developed microchannel offers advantages such as improved controllability of particle motion, lower requirement of applied voltage, reduced fouling and particle adhesion, etc.

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“…It is therefore relevant to shift from "through" to "planar" pores, i.e., restrictions inside microfluidic channels. These restrictions are easy to fabricate using substrates such as silicon, silicon oxide, and PDMS and can have similar applications as through micropores [110][111][112][113][114][115]. Such restrictions permit the optical view through transparent covering materials in addition to simpler fluidic control, parallelization, and multiplexing.…”

Section: From "Through" To "Planar" Poresmentioning

confidence: 99%

Polarization Induced Electro-Functionalization of Pore Walls: A Contactless Technology

et al. 2019

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This review summarizes recent advances in micro- and nanopore technologies with a focus on the functionalization of pores using a promising method named contactless electro-functionalization (CLEF). CLEF enables the localized grafting of electroactive entities onto the inner wall of a micro- or nano-sized pore in a solid-state silicon/silicon oxide membrane. A voltage or electrical current applied across the pore induces the surface functionalization by electroactive entities exclusively on the inside pore wall, which is a significant improvement over existing methods. CLEF’s mechanism is based on the polarization of a sandwich-like silicon/silicon oxide membrane, creating electronic pathways between the core silicon and the electrolyte. Correlation between numerical simulations and experiments have validated this hypothesis. CLEF-induced micro- and nanopores functionalized with antibodies or oligonucleotides were successfully used for the detection and identification of cells and are promising sensitive biosensors. This technology could soon be successfully applied to planar configurations of pores, such as restrictions in microfluidic channels.

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Proposal and experimental validation of the electrophoretic Coulter method for analyzing microparticles and biological cells

Cited by 14 publications

References 18 publications

The influence of humic acid on the toxicity of nano‐ZnO and Zn²⁺ to the Anabaena sp.

The influence of humic acid on the toxicity of nano‐ZnO and Zn²⁺ to the Anabaena sp.

Continuous manipulation and separation of particles using combined obstacle‐ and curvature‐induced direct current dielectrophoresis

Polarization Induced Electro-Functionalization of Pore Walls: A Contactless Technology

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Proposal and experimental validation of the electrophoretic Coulter method for analyzing microparticles and biological cells

Cited by 14 publications

References 18 publications

The influence of humic acid on the toxicity of nano‐ZnO and Zn2+ to the Anabaena sp.

The influence of humic acid on the toxicity of nano‐ZnO and Zn2+ to the Anabaena sp.

Continuous manipulation and separation of particles using combined obstacle‐ and curvature‐induced direct current dielectrophoresis

Polarization Induced Electro-Functionalization of Pore Walls: A Contactless Technology

Contact Info

Product

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The influence of humic acid on the toxicity of nano‐ZnO and Zn²⁺ to the Anabaena sp.

The influence of humic acid on the toxicity of nano‐ZnO and Zn²⁺ to the Anabaena sp.