Hierarchical self-assembly of actin in micro-confinements using microfluidics

Deshpande, Siddharth; Pfohl, Thomas

doi:10.1063/1.4752245

Cited by 39 publications

(62 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1A), where the entrance of the dead-end channel is connected to the main flow channel so that the solute concentration (c o ) can be regulated at the entrance. Additionally, the height of the dead-end channel is much thinner ( ≈10 μm) than the main channel ( ≈100 μm), such that the disturbance from the main channel can be minimized (15).…”

mentioning

confidence: 99%

Size-dependent control of colloid transport via solute gradients in dead-end channels

Shin

Sabass

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

220

261

View full text Add to dashboard Cite

Transport of colloids in dead-end channels is involved in widespread applications including drug delivery and underground oil and gas recovery. In such geometries, Brownian motion may be considered as the sole mechanism that enables transport of colloidal particles into or out of the channels, but it is, unfortunately, an extremely inefficient transport mechanism for microscale particles. Here, we explore the possibility of diffusiophoresis as a means to control the colloid transport in dead-end channels by introducing a solute gradient. We demonstrate that the transport of colloidal particles into the dead-end channels can be either enhanced or completely prevented via diffusiophoresis. In addition, we show that size-dependent diffusiophoretic transport of particles can be achieved by considering a finite Debye layer thickness effect, which is commonly ignored. A combination of diffusiophoresis and Brownian motion leads to a strong size-dependent focusing effect such that the larger particles tend to concentrate more and reside deeper in the channel. Our findings have implications for all manners of controlled release processes, especially for site-specific delivery systems where localized targeting of particles with minimal dispersion to the nontarget area is essential.T he ability of a particle to migrate along a local solute concentration gradient, which is referred to as diffusiophoresis, has been exploited to direct transport in a variety of systems, e.g., artificial swimmers (1, 2) and collective behaviors of active colloids (3, 4). One physical mechanism for diffusiophoresis originates from surface-solute interactions, where the solute gradient sets up an osmotic pressure gradient within a narrow interaction region. This gradient leads to fluid flow along the surface of a particle, in which case propulsion occurs in the opposite direction and is referred to as chemiphoresis (5, 6). In addition, differences in diffusivities between anions and cations lead to spontaneous electrophoresis of a particle, giving an additional propulsion mechanism. A particular feature of diffusiophoresis is that the diffusiophoretic mobility, or the phoretic velocity, of a particle is independent of its size, as long as the thickness of the interaction region, e.g., the Debye screening layer when the interaction is electrostatic, is much thinner than the size of the particle (6). This feature allows the utilization of diffusiophoresis for enhancing transport of microscale particles, leading to orders of magnitude higher transport rates compared with pure diffusion (7). However, this size independence could also be a source of frustration because it precludes useful effects such as sorting or controlling transport by particle size.We anticipate that size-independent particle mobility breaks down when the thickness of the surface-solute interaction region becomes comparable to the size of the particle. Already more than a century ago this feature has been well appreciated in the field of electrokinetics as the Hückel limit (8) w...

show abstract

mentioning

confidence: 99%

Size-dependent control of colloid transport via solute gradients in dead-end channels

Shin

Sabass

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

220

261

View full text Add to dashboard Cite

show abstract

“…15 tipstreaming, 16 and solvent extraction. 17,18 However, studies to date which produce liposomes utilize laminar-flow diffusional mixing.…”

mentioning

confidence: 99%

Analysis of a laminar-flow diffusional mixer for directed self-assembly of liposomes

et al. 2012

View full text Add to dashboard Cite

The present work describes the operation and simulation of a microfluidic laminarflow mixer. Diffusive mixing takes place between a core solution containing lipids in ethanol and a sheath solution containing aqueous buffer, leading to self assembly of liposomes. Present device architecture hydrodynamically focuses the lipid solution into a cylindrical core positioned at the center of a microfluidic channel of 125 Â 125-lm 2 cross-section. Use of the device produces liposomes in the size range of 100-300 nm, with larger liposomes forming at greater ionic strength in the sheath solution and at lower lipid concentration in the core solution. Finite element simulations compute the concentration distributions of solutes at axial distances of greater than 100 channel widths. These simulations reduce computation time and enable computation at long axial distances by utilizing long hexahedral elements in the axial flow region and fine tetrahedral elements in the hydrodynamic focusing region. Present meshing technique is generally useful for simulation of long microfluidic channels and is fully implementable using COMSOL Multiphysics. Confocal microscopy provides experimental validation of the simulations using fluorescent solutions containing fluorescein or enhanced green fluorescent protein.

show abstract

“…2(a)). [28][29][30] The concentration of an added or depleted biochemical reagent inside the flow-free chambers is therefore directly related to the diffusion time that has elapsed since the onset of an exchange buffer at the corresponding connecting channel. Variation of the RBC's microenvironment inside the flow-free chambers is further highly controlled and repeatable, e.g., by diffusive washing with different buffer solutions through the controlling channel ( Fig.…”

Section: Design and Operation Of The Blood Chipmentioning

confidence: 99%

A self-filling microfluidic device for noninvasive and time-resolved single red blood cell experiments

et al. 2016

Self Cite

View full text Add to dashboard Cite

Existing approaches to red blood cell (RBC) experiments on the single-cell level usually rely on chemical or physical manipulations that often cause difficulties with preserving the RBC's integrity in a controlled microenvironment. Here, we introduce a straightforward, self-filling microfluidic device that autonomously separates and isolates single RBCs directly from unprocessed human blood samples and confines them in diffusion-controlled microchambers by solely exploiting their unique intrinsic properties. We were able to study the photo-induced oxygenation cycle of single functional RBCs by Raman microscopy without the limitations typically observed in optical tweezers based methods. Using bright-field microscopy, our noninvasive approach further enabled the time-resolved analysis of RBC flickering during the reversible shape evolution from the discocyte to the echinocyte morphology. Due to its specialized geometry, our device is particularly suited for studying the temporal behavior of single RBCs under precise control of their environment that will provide important insights into the RBC's biomedical and biophysical properties. Published by AIP Publishing. [http://dx

show abstract

Hierarchical self-assembly of actin in micro-confinements using microfluidics

Cited by 39 publications

References 38 publications

Size-dependent control of colloid transport via solute gradients in dead-end channels

Size-dependent control of colloid transport via solute gradients in dead-end channels

Analysis of a laminar-flow diffusional mixer for directed self-assembly of liposomes

A self-filling microfluidic device for noninvasive and time-resolved single red blood cell experiments

Contact Info

Product

Resources

About