Electrically controlled rapid release of actives encapsulated in double-emulsion droplets

Jia, Yankai; Ren, Yukun; Hou, Likai; Liu, Weiyu; Jiang, Tianyi; Deng, Xiangyuan; Tao, Ye; Jiang, Hongyuan

doi:10.1039/c7lc01387f

Cited by 49 publications

(37 citation statements)

References 43 publications

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“…During this process, the AC signal was generated by a function generator (TGA 12104, TTi, Manchester, UK), and amplified by an amplifier (model 2350, TEGAM, Geneva, OH, USA). Under an appropriate field strength and frequency (30 V, 5 KHz) applied, the double-emulsion drop between the two electrodes ruptured immediately due to Maxwell−Wagner interfacial polarization [47][48][49].…”

Section: Electrotriggered Rupturing Of W/o/w Double-emulsion Dropsmentioning

confidence: 99%

Generation of Ultra-Thin-Shell Microcapsules Using Osmolarity-Controlled Swelling Method

Guo

Hou

et al. 2020

Micromachines

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Microcapsules are attractive core-shell configurations for studies of controlled release, biomolecular sensing, artificial microbial environments, and spherical film buckling. However, the production of microcapsules with ultra-thin shells remains a challenge. Here we develop a simple and practical osmolarity-controlled swelling method for the mass production of monodisperse microcapsules with ultra-thin shells via water-in-oil-in-water (W/O/W) double-emulsion drops templating. The size and shell thickness of the double-emulsion drops are precisely tuned by changing the osmotic pressure between the inner cores and the suspending medium, indicating the practicability and effectiveness of this swelling method in tuning the shell thickness of double-emulsion drops and the resultant microcapsules. This method enables the production of microcapsules even with an ultra-thin shell less than hundreds of nanometers, which overcomes the difficulty in producing ultra-thin-shell microcapsules using the classic microfluidic emulsion technologies. In addition, the ultra-thin-shell microcapsules can maintain their intact spherical shape for up to 1 year without rupturing in our long-term observation. We believe that the osmolarity-controlled swelling method will be useful in generating ultra-thin-shell polydimethylsiloxane (PDMS) microcapsules for long-term encapsulation, and for thin film folding, buckling and rupturing investigation.

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Section: Electrotriggered Rupturing Of W/o/w Double-emulsion Dropsmentioning

confidence: 99%

Generation of Ultra-Thin-Shell Microcapsules Using Osmolarity-Controlled Swelling Method

Guo

Hou

et al. 2020

Micromachines

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“…When the double‐emulsion droplets wrapped by microfibers are manually placed between electrodes and exposed to an AC electric field (100 kHz, 32.5 V), the inner core travels to one side of the shell interface due to the asymmetric Maxwell stress, which acts on the field‐induced dipole moment within the compound droplet having an initial core eccentricity . Meanwhile, since the time‐averaged dielectrophoresis (DEP) surface stress tends to mechanically expand the inner core and compress the outer surface of oil membrane at the same time, the oil film thins out gradually and eventually ruptures, ejecting the core liquid into the surrounding microfiber cavity. All the while, the ejective inner aqueous solution can leak into the ambient medium through the microfiber due to the porosity of hydrogel, only leaving oil droplet in the microfiber ( Figure a and Movie S1, Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

“…Microcarriers with dual or more compartments for parallel co‐encapsulation are fabricated by templates of double‐emulsion droplets. Such kind of microcarriers with single‐layer shells of the same material are only suitable for simultaneous release of distinct encapsulants when exposed to one kind of stimuli . To achieve the sequential release of different contents, double microcapsules, or called capsules‐in‐capsules, are developed by using the quadruple emulsions as templates.…”

Section: Introductionmentioning

confidence: 99%

Compound‐Droplet‐Pairs‐Filled Hydrogel Microfiber for Electric‐Field‐Induced Selective Release

Deng

Ren

Hou

et al. 2019

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The separate co‐encapsulation and selective controlled release of multiple encapsulants in a predetermined sequence has potentially important applications for drug delivery and tissue engineering. However, the selective controlled release of distinct contents upon one triggering event for most existing microcarriers still remains challenging. Here, novel microfluidic fabrication of compound‐droplet‐pairs‐filled hydrogel microfibers (C‐Fibers) is presented for two‐step selective controlled release under AC electric field. The parallel arranged compound droplets enable the separate co‐encapsulation of distinct contents in a single microfiber, and the release sequence is guaranteed by the discrepancy of the shell thickness or core conductivity of the encapsulated droplets. This is demonstrated by using a high‐frequency electric field to trigger the first burst release of droplets with higher conductivity or thinner shell, followed by the second release of the other droplets under low‐frequency electric field. The reported C‐Fibers provide novel multidelivery system for a wide range of applications that require controlled release of multiple ingredients in a prescribed sequence.

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“…Electrohydrodynamics (EHDs) has been acquiring unprecedentedly increasing attention from the microfluidic community since the last two decades [4][5][6]. Traditional DC electroosmosis (EO) [7,8], electrowetting on dielectrics [9], injection EHD [10], conduction EHD [11], traveling-wave induction EHD [12][13][14][15], inducedcharge electroosmosis (ICEO) [16][17][18][19][20][21][22][23][24], dielectrophoresis (DEP) [25][26][27][28][29][30], electrothermal (ET) induced flow [31][32][33][34][35][36][37], and electroconvective instability (EI) [38][39][40] near a permselective membrane are all authoritative methodologies where electric fields are employed to actuate liquid solutions in miniaturization systems.…”

Section: Introductionmentioning

confidence: 99%

A microscopic physical description of electrothermal‐induced flow for control of ion current transport in microfluidics interfacing nanofluidics

et al. 2019

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The phenomenon of electrothermal (ET) convection has recently captured great attention for transporting fluidic samples in microchannels embedding simple electrode structures. In the classical model of ET‐induced flow, a conductivity gradient of buffer medium is supposed to arise from temperature‐dependent electrophoretic mobility of ionic species under uniform salt concentrations, so it may not work well in the presence of evident concentration perturbation within the background electrolyte. To solve this problem, we develop herein a microscopic physical description of ET streaming by fully coupling a set of Poisson‐Nernst‐Planck‐Navier‐Stokes equations and temperature‐dependent fluid physicochemical properties. A comparative study on a standard electrokinetic micropump exploiting asymmetric electrode arrays indicates that, our microscopic model always predicts a lower ET pump flow rate than the classical macroscopic model even with trivial temperature elevation in the liquid. Considering a continuity of total current density in liquids of inhomogeneous polarizability, a moderate degree of fluctuation in ion concentrations on top of the electrode array is enough to exert a significant influence on the induction of free ionic charges, rendering the enhanced numerical treatment much closer to realistic experimental measurement. Then, by placing a pair of thin‐film resistive heaters on the bottom of an anodic channel interfacing a cation‐exchange medium, we further provide a vivid demonstration of the enhanced model's feasibility in accurately resolving the combined Coulomb force due to the coexistence of an extended space charge layer and smeared interfacial polarizations in an externally‐imposed temperature gradient, while this is impossible with conventional linear approximation. This leads to a reliable method to achieve a flexible regulation on spatial‐temporal evolution of ion‐depletion layer by electroconvective mixing. These results provide useful insights into ET‐based flexible control of micro/nanoscale solid entities in modern micro‐total‐analytical systems.

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Electrically controlled rapid release of actives encapsulated in double-emulsion droplets

Cited by 49 publications

References 43 publications

Generation of Ultra-Thin-Shell Microcapsules Using Osmolarity-Controlled Swelling Method

Generation of Ultra-Thin-Shell Microcapsules Using Osmolarity-Controlled Swelling Method

Compound‐Droplet‐Pairs‐Filled Hydrogel Microfiber for Electric‐Field‐Induced Selective Release

A microscopic physical description of electrothermal‐induced flow for control of ion current transport in microfluidics interfacing nanofluidics

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