Microfluidic Production of Biodegradable Microcapsules for Sustained Release of Hydrophilic Actives

Lee, Tae Yong; Ku, Minhee; Kim, Bomi; Lee, Sang‐Min; Yang, Jaemoon; Kim, Shin‐Hyun

doi:10.1002/smll.201700646

Cited by 65 publications

(57 citation statements)

References 66 publications

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“…If these two co‐flowing fluids meet a third fluid that is immiscible with the sheath fluid, double‐emulsion drops form. If the sheath is thin, double emulsions have ultrathin shells . The thin shell of these double emulsions significantly increases their stability against coalescence .…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, the double‐emulsion drops only form when the aqueous core flows through the orifice of the left capillary. By contrast, when only oil flows through the orifice of the left capillary, single oil drops form . We inject the second oil phase (O4) through the interstices of the first square and the middle cylindrical capillaries, as shown schematically in Figure a.…”

Section: Resultsmentioning

confidence: 99%

“…As the same occurs in the first junction, four different compositions of drops are formed: the quadruple‐emulsion drops (W1/O2/W3/O4/W5), triple‐emulsion drops (O2/W3/O4/W5), double‐emulsion drops (W3/O4/W5), and single oil drops (O4/W5). However, the quadruple‐ and double‐emulsion drops can easily be separated from the triple‐ and single‐emulsion drops by exploiting the density difference . The average density of double‐ or quadruple‐emulsion drops is similar to that of the aqueous phases (W1 and W3) because the oil shells are as thin as ≈1 µm.…”

Section: Resultsmentioning

confidence: 99%

“…The thickness of the PLA membranes of the inner and outer capsules is significantly reduced during the evaporation of the organic solvent, such that the solidified PLA shells are as thin as 100 nm, as shown in Figure d; the oil shell before the consolidation is estimated from the volume fraction of PLA in the solution, 13.5 v/v%, to be ≈740 nm. The resulting microcapsules whose membranes are made of polymerized ETPTA show no leakage at least for several months, and those made of consolidated PLA (or PCL) show less than 10% leakage during a long‐term storage for a month …”

Section: Resultsmentioning

confidence: 99%

“…For rigid polymeric shells, negative osmotic pressures can cause small cracks in the shell due to an extensional stress along the lateral direction exerted by the expansion. These cracks can render capsules permeable to encapsulants . To test if the negative osmotic pressure can be used as a trigger for a sequential release of encapsulants from double capsules, we produce double capsules composed of two PLA membranes.…”

Section: Resultsmentioning

confidence: 99%

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Microfluidic Production of Capsules‐in‐Capsules for Programed Release of Multiple Ingredients

Lee

Amstad

et al. 2018

Adv Materials Technologies

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Capsules with thin shells have a high‐loading capacity and are thus well‐suited containers for reagents that must be stored in confined volumes. Capsules contained in larger capsules, so‐called double capsules, allow the encapsulation of distinct reagents within small, defined, well‐separated volumes. Therefore, they offer possibilities to initiate reactions in confined volumes and to release distinct bioactives sequentially while minimizing the risk for cross contaminations. In this study, a new microfluidic capillary device is presented that enables the assembly of water‐oil‐water‐oil‐water (W/O/W/O/W) quadruple‐emulsion drops whose oil layers are ultra thin. These quadruple emulsions can be converted into double capsules with thin membranes through either evaporation‐induced consolidation of biodegradable polymers or photopolymerization of monomers. It is demonstrated that the membrane composition of the inner and outer capsules can be independently selected to enable programed release of distinct encapsulants. For example, biodegradable polymers with two different degradation rates are employed as the membrane materials that enable sequential release of two different encapsulants. In addition, the release of the encapsulants can be triggered by external stimuli such as osmotic pressure. This new class of double capsules provides new opportunities for drug delivery and screening assays that require sequential release of multiple water‐soluble ingredients.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 3 more Smart Citations

Microfluidic Production of Capsules‐in‐Capsules for Programed Release of Multiple Ingredients

Lee

Amstad

et al. 2018

Adv Materials Technologies

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Thermo‐Responsive Microcapsules with Tunable Molecular Permeability for Controlled Encapsulation and Release

Choi

Hwang

Han

et al. 2021

Adv Funct Materials

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Microcapsules with regulated transmembrane transport are of great importance for various applications. The membranes with a tunable cut‐off threshold of permeation provide advanced functionality. Here, thermo‐responsive microcapsules are designed, whose hydrogel membrane shows a tunable cut‐off threshold of permeation with temperature. To produce the microcapsules, water‐in‐oil‐in‐water (W/O/W) double‐emulsion droplets are microfluidically produced, whose oil shell contains oil‐soluble hydrogel precursor of poly(N, N‐diethylacrylamide) copolymerized with benzophenone (PDEAM‐BP). The PDEAM hydrogels, crosslinked by BP, show volume‐phase transition around 34 °C, which makes the microcapsules with the PDEAM hydrogel membrane thermo‐responsive. The microcapsules show temperature‐dependent changes in radius and membrane thickness. More importantly, the cut‐off threshold of permeation can be reversibly adjusted by temperature control as the degree of swelling decreases with temperature. This enables the molecule‐selective encapsulation and the controlled release of the encapsulants in a programmed manner by adjusting the temperature. The microcapsules can be rendered to be photo‐responsive by encapsulating photothermal polydopamine nanoparticles during the microfluidic operation, which allows the control of the degree of swelling with near‐infrared (NIR) irradiation. The thermo‐ and photo‐responsive microcapsules with a tunable cut‐off threshold are appealing as a new platform for drug carriers, microreactors, and microsensors.

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Recent Progress of Conductive Hydrogel Fibers for Flexible Electronics: Fabrications, Applications, and Perspectives

Liu

Wei

et al. 2023

Adv Funct Materials

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lightweight, portable, foldable, stretchable, and biocompatible are triggering the intense interests of researchers from multidisciplinary fields like biology, material science, and chemistry. [9][10][11] Nowadays, great attempts have been devoted to developing advanced flexible electronics by integrating various inorganic or organic traditional conductive functional materials with flexible electrochemically non-active elastic substrates. [12][13][14][15][16][17] Generally, traditional conductive functional materials encounter the shortcomings such as high price, inherent rigidity, weak biocompatibility, poor mechanical, and inferior interface bonding properties, which are employed to evaluate the performance of the flexible electronics materials. Therefore, pursuing these materials with practical applications is an emergent issue in the research field.Nevertheless, in numerous conductive functional materials, hydrogels with 3D network structures have been largely selected as the excellent candidates due to their high water content, excellent biocompatibility and biodegradability properties, high elasticity, and outstanding stimulus responsiveness. [18][19][20][21][22][23] Conductive hydrogels are generally constructed via integrating various conductive substances into the hydrogel matrix, which are comprised of carbon materials (carbon nanotubes (CNTs), graphite), metal oxides, metal sulfides, metal nanoparticles and conductive polymers (polyaniline (PANI), polypyrrole (PPy), poly (3,4-ethylenedioxythiophene) (PEDOT:PSS)). [24][25][26][27][28][29][30] For example, Han et al. fabricated a CNTs-based conductive hydrogel for strain sensors by in situ polymerization of acrylic acid and acrylamide in water/glycerol solutions in the presence of polydopamine-decorated CNTs. [28] Devaki et al. reported a 3D Ag nanoparticles-polyacrylic acid conductive hydrogel via combining in situ polymerization of acrylic acid and reduction of Ag + . [29] Duan et al. constructed a robust and force-sensitive conductive hydrogel employing synthesizing polyacrylamide and PANI in closely packed swollen chitosan microspheres. [30] According to the different configurations of hydrogels, conductive hydrogels are allowed to be processed into 3D bulk gels, 2D gel films, 1D gel fibers, and 0D microgels. [31][32][33][34][35][36] The mechanical flexibility of 1D fibrous configuration is superior to that of 3D bulk or 2D film configuration due to its well-oriented polymer chains, light weight, and low dimensions for flexible electronics. Moreover, ultra-flexible fibrous materials can be easily woven into diverse soft and breathable fabrics, which

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Microfluidic Production of Biodegradable Microcapsules for Sustained Release of Hydrophilic Actives

Cited by 65 publications

References 66 publications

Microfluidic Production of Capsules‐in‐Capsules for Programed Release of Multiple Ingredients

Microfluidic Production of Capsules‐in‐Capsules for Programed Release of Multiple Ingredients

Thermo‐Responsive Microcapsules with Tunable Molecular Permeability for Controlled Encapsulation and Release

Recent Progress of Conductive Hydrogel Fibers for Flexible Electronics: Fabrications, Applications, and Perspectives

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