Microfluidic Microdialysis: Spatiotemporal Control over Solution Microenvironments Using Integrated Hydrogel Membrane Microwindows

Paustian, Joel S.; Azevedo, Rodrigo Nery; Lundin, Sean-Thomas B.; Gilkey, Matthew J.; Squires, Todd M.

doi:10.1103/physrevx.3.041010

Cited by 27 publications

(47 citation statements)

References 109 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We have recently developed a microfluidic system that allows systematic and quantitative measurement of DP mobilities [13]. Integrated hydrogel microwindow membranes [21] enable a wide range of solute gradients to be imposed without generating convective flows, and particle DP to be visualized directly and measured quantitatively.…”

Section: Diffusiophoretic Focusing Of Suspended Colloidsmentioning

confidence: 99%

Diffusiophoretic Focusing of Suspended Colloids

et al. 2016

Self Cite

View full text Add to dashboard Cite

Section: Diffusiophoretic Focusing Of Suspended Colloidsmentioning

confidence: 99%

Diffusiophoretic Focusing of Suspended Colloids

et al. 2016

Self Cite

View full text Add to dashboard Cite

“…Such theories have been developed for gradients of electrolytes (35,37) and nonelectrolytes (51), yet difficulties in establishing sufficiently strong, stable gradients have prevented systematic experimental measurements (as is routine for electrophoresis). Recent developments in microfluidics, however, have enabled more direct studies of DP (40,(52)(53)(54)(55)(56). In particular, we have recently developed a microfluidic device (56) that enables gradients to be directly imposed, and diffusiophoretic migration to be visualized and measured under various solute and solvent gradients (40).…”

Section: Soluto-inertial Beaconmentioning

confidence: 99%

Soluto-inertial phenomena: Designing long-range, long-lasting, surface-specific interactions in suspensions

Banerjee

Williams

Azevedo

et al. 2016

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

Self Cite

View full text Add to dashboard Cite

Equilibrium interactions between particles in aqueous suspensions are limited to distances less than 1 μm. Here, we describe a versatile concept to design and engineer nonequilibrium interactions whose magnitude and direction depends on the surface chemistry of the suspended particles, and whose range may extend over hundreds of microns and last thousands of seconds. The mechanism described here relies on diffusiophoresis, in which suspended particles migrate in response to gradients in solution. Three ingredients are involved: a soluto-inertial "beacon" designed to emit a steady flux of solute over long time scales; suspended particles that migrate in response to the solute flux; and the solute itself, which mediates the interaction. We demonstrate soluto-inertial interactions that extend for nearly half a millimeter and last for tens of minutes, and which are attractive or repulsive, depending on the surface chemistry of the suspended particles. Experiments agree quantitatively with scaling arguments and numerical computations, confirming the basic phenomenon, revealing design strategies, and suggesting a broad set of new possibilities for the manipulation and control of suspended particles.olloidal suspensions and emulsions of 10-nm to 10-μm particles play a central role in a wide variety of industrial, technological, biological, and everyday processes. Everyday goods, including shampoos, inks, vaccines, paints, and foodstuffs as well as industrial products such as drilling muds, ceramics, and pesticides, rely fundamentally on stably suspended microparticles for their creation and/or operation. This incredible versatility derives from the extensive variety of properties (e.g., mechanical, optical, and chemical) attainable in suspension through a generic set of physicochemical strategies (1-4). A proper understanding of the stability and dynamics of suspensions in general thus underpins both fundamental science and technological applications.The properties and performance of suspensions depend preeminently on the effective interactions between particles. The celebrated Derjaguin-Landau-Verwey-Overbeek (DLVO) theory (5-7) balances electrostatic interactions (typically repulsive) between charged colloids-as screened by ions in the surrounding electrolyte-against van der Waals attractions, and successfully predicts the stability, phase behavior, and response of electrostatically stabilized suspensions. Additional (non-DLVO) forces can also be used to stabilize or destabilize colloidal suspensions. Grafted or adsorbed macromolecules provide short-range steric repulsions that stabilize suspended particles against van der Waals-induced flocculation (8-11). By contrast, nonadsorbed macromolecules that remain dispersed in solution introduce entropic depletion attractions whose strength and range is set by the size and concentration of depletants (12, 13). Such depletion interactions scale with thermal energy (k B T), and thus enable tunable and reversible attractions (14, 15). Clever design of shaped or patterned coll...

show abstract

“…27 This method allows strong gradients to be established perpendicular to and entirely within the imaging plane, and the small channel dimensions suppress the hydrodynamic flows and instabilities often associated with strong concentration gradients. Although the transmembrane flow velocities arising with HMMs prepared in that work were already quite small small (u P ≲1 μm/s), the diffusiophoretic migration measured in the present work (u DP ∼ 1 μm/s) can be slow enough that even smaller transmembrane flows are required.…”

Section: ■ Methodsmentioning

confidence: 99%

“…26 We have recently developed a method to impose local solute and solvent gradients within microchannels, which enabled the first direct microscopic visualization of solvophoretic migration. 27 To set up strong gradients within channels, we photopolymerize thin hydrogel membranes into so-called "microfluidic stickers" devices 28 made from the UV-curable optical adhesive NOA-81 (Norland), based on their superior solvent-compatibility compared with standard PDMS devices. Our method allows high-resolution velocity measurements of diffusiophoresis under diverse chemical gradients.…”

Section: ■ Introductionmentioning

confidence: 99%

Direct Measurements of Colloidal Solvophoresis under Imposed Solvent and Solute Gradients

et al. 2015

Self Cite

View full text Add to dashboard Cite

We describe a microfluidic system that enables direct visualization and measurement of diffusiophoretic migration of colloids in response to imposed solution gradients. Such measurements have proven difficult or impossible in macroscopic systems due to difficulties in establishing solution gradients that are sufficiently strong yet hydrodynamically stable. We validate the system with measurements of the concentration-dependent diffusiophoretic mobility of polystyrene colloids in NaCl gradients, confirming that diffusiophoretic migration velocities are proportional to gradients in the logarithm of electrolyte concentration. We then perform the first direct measurement of the concentration-dependent "solvophoretic" mobility of colloids in ethanol−water gradients, whose dependence on concentration and gradient strength was not known either theoretically or experimentally, but which our measurements reveal to be proportional to the gradient in the logarithm of ethanol mole fraction. Finally, we examine solvophoretic migration under a variety of qualitatively distinct chemical gradients, including solvents that are miscible or have finite solubility with water, an electrolyte for which diffusiophoresis proceeds down concentration gradients (unlike for most electrolytes), and a nonelectrolyte (sugar). Our technique enables the direct characterization of diffusiophoretic mobilities of various colloids under various solvent and solute gradients, analogous to the electrophoretic ζ-potential measurements that are routinely used to characterize suspensions. We anticipate that such measurements will provide the feedback required to test and develop theories for solvophoretic and diffusiophoretic migration and ultimately to the conceptual design and engineering of particles that respond in a desired way to their chemical environments.

show abstract

Microfluidic Microdialysis: Spatiotemporal Control over Solution Microenvironments Using Integrated Hydrogel Membrane Microwindows

Cited by 27 publications

References 109 publications

Diffusiophoretic Focusing of Suspended Colloids

Diffusiophoretic Focusing of Suspended Colloids

Soluto-inertial phenomena: Designing long-range, long-lasting, surface-specific interactions in suspensions

Direct Measurements of Colloidal Solvophoresis under Imposed Solvent and Solute Gradients

Contact Info

Product

Resources

About