Collapse of Gels in an Electric Field

Tanaka, Toyoichi; Nishio, Izumi; Sun, Shao‐Tang; Ueno-Nishio, Shizue

doi:10.1126/science.218.4571.467

Cited by 1,262 publications

(710 citation statements)

References 5 publications

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“…Fortunately, there are hydrogels that respond to external stimuli other than the solution's salt concentration and retain the feature of self-regulation without a need for separate actuating fluids. Among the hydrogels that respond to glucose [29], antigens [30], electric field [31], magnetic field [32], and temperature [33], we selected the temperature responsive poly(N-isopropylacrylamide), Poly(NIPAM), or PNIPAAm, for the construction of our valves. An unconstrained hydrogel, saturated with aqueous solution, swells by as much as a factor of 10 when the temperature decreases from above to below the gel's lower critical solution temperature (LCST).…”

Section: Introductionmentioning

confidence: 99%

Self-Actuated, Thermo-Responsive Hydrogel Valves for Lab on a Chip

Wang

Chen

Mauk

et al. 2005

Biomed Microdevices

146

108

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An easy to fabricate, thermally-actuated, self-regulated hydrogel valve for flow control in pneumatically driven, microfluidic systems is described. This microvalve takes advantage of the properties of the hydrogel, poly(Nisopropylacrylamide), as well as the aqueous fluid itself to realize flow control. The valve was designed for use in a diagnostic system fabricated with polycarbonate and aimed at the detection of pathogens in oral fluids at the location of the sample collection. The paper describes the construction and characterization of the hydrogel valves and their application for flow control, sample and reagent metering, sample distribution into multiple analysis paths, and the sealing of a polymerase chain reaction (PCR) reactor to suppress bubble formation. The hydrogel-based flow control is electronically addressable, does not require any moving parts, introduces minimal dead volume, is leakage and contaminant free, and is biocompatible. KeywordsMicrovalve, microfluidics, hydrogel, lab-on-a-chip, metering, distribution, PCR Wang, J., Chen, Z., Mauk, M., Hong, K-S, Li, M., Yang, S., and Bau, H., H Wang, J., Chen, Z., Mauk, M., Hong, K-S, Li, M., Yang, S., and Bau, H., H., 2005, Self-Actuated, ThermoResponsive Hydrogel Valves for Lab on a Chip, Biomedical Microdevices 7 (4), 313-322.., 2005, Self-Actuated, Thermo-Responsive Hydrogel Valves for Lab on a Chip, Biomedical Microdevices 7 (4), 313-322. ABSTRACTAn easy to fabricate, thermally-actuated, self-regulated hydrogel valve for flow control in pneumatically driven, microfluidic systems is described. This microvalve takes advantage of the properties of the hydrogel, poly(N-isopropylacrylamide), as well as the aqueous fluid itself to realize flow control. The valve was designed for use in a diagnostic system fabricated with polycarbonate and aimed at the detection of pathogens in oral fluids at the location of the sample collection. The paper describes the construction and characterization of the hydrogel valves and their application for flow control, sample and reagent metering, sample distribution into multiple analysis paths, and the sealing of a polymerase chain reaction (PCR) reactor to suppress bubble formation. The hydrogel-based flow control is electronically addressable, does not require any moving parts, introduces minimal dead volume, is leakage and contaminant free, and is biocompatible.

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Section: Introductionmentioning

confidence: 99%

Self-Actuated, Thermo-Responsive Hydrogel Valves for Lab on a Chip

Wang

Chen

Mauk

et al. 2005

Biomed Microdevices

146

108

View full text Add to dashboard Cite

show abstract

“…They have become extensively attractive due to their ability to simulate biological tissues and respond reversibly to the external stimuli [1][2][3][4][5][6][7][8][9][10]. However, most conventional soft and wet hydrogels usually show extremely poor functions due to their amorphous structure, i.e., random cross-linking polymer chain at molecular level, in contrast with the natural bio-tissue that possesses well-defined hierarchy structure from molecular level to macroscopic scale.…”

Section: Introductionmentioning

confidence: 99%

Multi-functions of hydrogel with bilayer-based lamellar structure

Haque

Gong

2013

Reactive and Functional Polymers

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A novel hybrid hydrogel has been developed by combining bilayer-based lamellar structure of a self-assembled polymer surfactant and polymer network of conventional hydrogel system. A wide range of lamellar structure from micro-domain up to macro-domain (cm-scale) has been successfully generated in the hydrogel. Flat, infinitely large, and perfectly aligned lamellar macro-domain was formed by applying mechanical shear to the gel forming precursor solution containing monomer, cross-linker, and initiator. The obtained hydrogel system contains macroscopic, single-domain, periodical stacking of integrated microscopic lamellar bilayers inside the polymer matrix of the hydrogel. Periodical stacking of the bilayers in the hydrogel selectively diffract visible light to exhibit magnificent structural color. Due to the uniaxial orientation of the bilayer, the hydrogel possesses superb functions that have never been realized before, such as the one-dimensional swelling, anisotropic Young's modulus, anisotropic molecular permeation, and diffusion. Furthermore, the hydrogel exhibits excellent color tuning ability over a wide spectrum range by mechanical stimuli.3

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“…It is swollen in solvent, and many kinds of polymeric gels that undergo abrupt volume change in response to external stimuli, such as a change in solvent composition, 28 temperature, 29,30 pH, 31 and electric field, 32 have been developed over the last two decades. Gels consisting of N-isopropylacrylamide (NIPAAm), which swell by cooling and deswell by heating, have been widely studied.…”

Section: Introductionmentioning

confidence: 99%

Propagating Spiral Waves Obtained in a Catalyst-Immobilized Gel Membrane by the Belousov-Zhabotinsky Reaction System

Kim¹,

Jo²,

Basavaraja³

et al. 2010

Bulletin of the Korean Chemical Society

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The formation of diverse spiral waves was studied in a polyacrylamide gel membrane with ruthenium(4-vinyl-4'-methyl-2,2'-bipyridine)bis(2,2'-bipyridine)bis(hexafluorophosphate) by a gas-free Belousov-Zhabotinisky (BZ) reaction system containing 1,4-cyclohexanedione (1,4-CHD). The gel membrane was found to be receptive for observing propagating waves since a clearer wave-train is obtained during a long reaction time without any disturbance from the immobilized metal catalyst which can be dissolved into the highly acidic solution of the BZ system. The distinctive waves in the system basically depend on both BrO3  and 1,4-CHD in the initial phase, and are influenced by the intensity of illumination of visible light.

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Collapse of Gels in an Electric Field

Abstract: An infinitesimal change in electric potential across a polyelectrolyte gel produces a discrete, reversible volume change. The volume of the collapsed gel can be several hundred times smaller than that of the swollen gel.

Cited by 1,262 publications

References 5 publications

Self-Actuated, Thermo-Responsive Hydrogel Valves for Lab on a Chip

Self-Actuated, Thermo-Responsive Hydrogel Valves for Lab on a Chip

Multi-functions of hydrogel with bilayer-based lamellar structure

Propagating Spiral Waves Obtained in a Catalyst-Immobilized Gel Membrane by the Belousov-Zhabotinsky Reaction System

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