Hydrodynamic focusing—a versatile tool

Golden, Joel P.; Justin, Gusphyl; Nasir, Mansoor; Ligler, Frances S.

doi:10.1007/s00216-011-5415-3

Cited by 60 publications

(52 citation statements)

References 41 publications

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“…24 These devices provide several advantages over other methods of particle or cell manipulation (e.g., magnetophoresis, 25,26 dielectrophoresis 27 or inertial forcing 28 ) due to their ability to process entities without high magnetic susceptibilities, electric polarizabilities or a narrow size dispersity. Furthermore, the focusing nodes of an acoustic standing wave can be positioned far from the source of excitation, which is something that is not possible by static magnetic or electric fields as per Earnshaw's theorem.…”

Section: Discussionmentioning

confidence: 99%

Fabrication and Operation of Acoustofluidic Devices Supporting Bulk Acoustic Standing Waves for Sheathless Focusing of Particles

Shields

Cruz

Ohiri

et al. 2016

JoVE

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Acoustophoresis refers to the displacement of suspended objects in response to directional forces from sound energy. Given that the suspended objects must be smaller than the incident wavelength of sound and the width of the fluidic channels are typically tens to hundreds of micrometers across, acoustofluidic devices typically use ultrasonic waves generated from a piezoelectric transducer pulsating at high frequencies (in the megahertz range). At characteristic frequencies that depend on the geometry of the device, it is possible to induce the formation of standing waves that can focus particles along desired fluidic streamlines within a bulk flow. Here, we describe a method for the fabrication of acoustophoretic devices from common materials and clean room equipment. We show representative results for the focusing of particles with positive or negative acoustic contrast factors, which move towards the pressure nodes or antinodes of the standing waves, respectively. These devices offer enormous practical utility for precisely positioning large numbers of microscopic entities (e.g., cells) in stationary or flowing fluids for applications ranging from cytometry to assembly.

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Section: Discussionmentioning

confidence: 99%

Fabrication and Operation of Acoustofluidic Devices Supporting Bulk Acoustic Standing Waves for Sheathless Focusing of Particles

Shields

Cruz

Ohiri

et al. 2016

JoVE

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“…42,46,47 Using appropriate flow rates, the effect of lateral diffusion of the soluble species can be minimized, 46 maintaining a steady state focal stream for long periods of time. Furthermore, by tuning the relative flow rates of the flanking and focal streams, the width of the focal stream can be controlled.…”

Section: A Device Overviewmentioning

confidence: 99%

An open-chamber flow-focusing device for focal stimulation of micropatterned cells

et al. 2016

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Microfluidic devices can deliver soluble factors to cell and tissue culture microenvironments with precise spatiotemporal control. However, enclosed microfluidic environments often have drawbacks such as the need for continuous culture medium perfusion which limits the duration of experiments, incongruity between microculture and macroculture, difficulty in introducing cells and tissues, and high shear stress on cells. Here, we present an open-chamber microfluidic device that delivers hydrodynamically focused streams of soluble reagents to cells over long time periods (i.e., several hours). We demonstrate the advantage of the open chamber by using conventional cell culture techniques to induce the differentiation of myoblasts into myotubes, a process that occurs in 7-10 days and is difficult to achieve in closed chamber microfluidic devices. By controlling the flow rates and altering the device geometry, we produced sharp focal streams with widths ranging from 36 lm to 187 lm. The focal streams were reproducible ($12% variation between units) and stable ($20% increase in stream width over 10 h of operation). Furthermore, we integrated trenches for micropatterning myoblasts and microtraps for confining single primary myofibers into the device. We demonstrate with finite element method (FEM) simulations that shear stresses within the cell trench are well below values known to be deleterious to cells, while local concentrations are maintained at $22% of the input concentration. Finally, we demonstrated focused delivery of cytoplasmic and nuclear dyes to micropatterned myoblasts and myofibers. The open-chamber microfluidic flow-focusing concept combined with micropatterning may be generalized to other microfluidic applications that require stringent long-term cell culture conditions. Published by AIP Publishing. [http://dx

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“…13 Hydrodynamic focusing is the steering of the central stream with a secondary boundary stream, where under the proper conditions these fluids do not mix ( Fig. 1).…”

Section: Microfluidic Chips For Initial Folding Eventsmentioning

confidence: 99%

Microfluidic chips with multi-junctions: an advanced tool in recovering proteins from inclusion bodies

Yamaguchi

Miyazaki

2015

Bioengineered

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A ctive recombinant proteins are used for studying the biological functions of genes and for the development of therapeutic drugs. Overexpression of recombinant proteins in bacteria often results in the formation of inclusion bodies, which are protein aggregates with nonnative conformations. Protein refolding is an important process for obtaining active recombinant proteins from inclusion bodies. However, the conventional refolding method of dialysis or dilution is time-consuming and recovered active protein yields are often low, and a cumbersome trial-and-error process is required to achieve success. To circumvent these difficulties, we used controllable diffusion through laminar flow in microchannels to regulate the denaturant concentration. This method largely aims at reducing protein aggregation during the refolding procedure. This Commentary introduces the principles of the protein refolding method using microfluidic chips and the advantage of our results as a tool for rapid and efficient recovery of active recombinant proteins from inclusion bodies.

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Hydrodynamic focusing—a versatile tool

Cited by 60 publications

References 41 publications

Fabrication and Operation of Acoustofluidic Devices Supporting Bulk Acoustic Standing Waves for Sheathless Focusing of Particles

Fabrication and Operation of Acoustofluidic Devices Supporting Bulk Acoustic Standing Waves for Sheathless Focusing of Particles

An open-chamber flow-focusing device for focal stimulation of micropatterned cells

Microfluidic chips with multi-junctions: an advanced tool in recovering proteins from inclusion bodies

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