Microfluidic preparation of a highly active and stable catalyst by high performance of encapsulation of polyvinylpyrrolidone (PVP)-Pt nanoparticles in microcapsules

Park

J of Chemical Tech & Biotech

et al. 2016

Self Cite

BACKGROUND: Generation of monodisperse hydrogel microspheres is needed to make exquisite microenvironments, provide effective delivery system, and obtain reliable results. In this work, we present a simple microfluidic approach for the preparation of monodisperse pectin hydrogel microspheres because of efficient collection and shape of hydrogel.RESULTS: Based on the mechanism of in situ gelation and efficient collection, aqueous droplets of pectin polysaccharides are continuously generated in an immiscible continuous phase dissolving divalent metal ions, such as calcium. Under in situ gelation conditions, calcium ions are diffused into the interface between the continuous phase and the aqueous droplets, which triggers gelation of the pectin polysaccharides. The settling collection method, which involves dropping consecutive hydrogels from the outlet hole, is able to maintain the shape of the soft pectin hydrogels. Thus, pectin microspheres produced show high monodispersity (a coefficient of variation of 3.5%). In addition, the stiffness of the pectin hydrogels produced can be manipulated by a simple change of the concentration of pectin in the aqueous phase. The control of the mechanical properties can also be confirmed by measurement of the deformation of the pectin hydrogels using the micropipette aspiration method. Furthermore, the versatility of this approach enables the preparation of monodisperse pectin hydrogels with the capability to encapsulate or release nanoparticles on demand under mild conditions. The pectin microspheres are freely manipulated by the control of magnetic fields. CONCLUSION:We believe that the in situ microfluidic synthesis method combined with settling collection provides an efficient approach for the preparation of soft, monodisperse hydrogel microspheres.

Section: Introductionmentioning

confidence: 99%

Microfluidic synthesis of monodisperse pectin hydrogel microspheres based on in situ gelation and settling collection

Park

J of Chemical Tech & Biotech

et al. 2016

Self Cite

“…Moreover, we believe that the microcapsules will provide new opportunities as a new platform for microreactors and capsule‐type microsensors as the transmembrane transport is regulatable. [ 24–26,28,36,50 ]…”

Section: Discussionmentioning

confidence: 99%

“…[ 14,19–23 ] In addition, the semi‐permeable microcapsules are useful for the protection of delicate catalysts or enzymes against large contaminants while allowing the exchange of reactants and products with the surrounding. [ 24,25 ] Similarly, nanoparticle‐based sensors can be encapsulated for the detection of small target molecules without contamination. [ 18,26–28 ]…”

Section: Introductionmentioning

confidence: 99%

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

Choi

Hwang

Han

et al. 2021

Adv Funct Materials

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.

“…have made endeavors in colloidal precious metals using macromolecule as stabilizer, and alcohol as reductant. Preparation of noble metal particles stabilized by polyvinylpyrrolidone and then reduced by ethanol has great advantages, such as (1) small metal particle and the narrow distribution range; (2) adjustable particle size depend on the preparation conditions; (3) high catalytic activity; (4) easy operation and good repeatability . However, most of noble metal colloids are used in sol form as the effective metallic catalysts which are difficult to separate and recycle .…”

Section: Figurementioning

confidence: 99%

“…Preparation of noble metal particles stabilized by polyvinylpyrrolidone and then reduced by ethanol has great advantages, such as (1) small metal particle and the narrow distribution range; (2) adjustable particle size depend on the preparation conditions; (3) high catalytic activity; (4) easy operation and good repeatability . However, most of noble metal colloids are used in sol form as the effective metallic catalysts which are difficult to separate and recycle . Heterogeneous supported nano‐metallic colloid catalysts prepared through combination of nano‐metallic colloids and carriers depending on physical or chemical effects is a better choice .…”

Section: Figurementioning

confidence: 99%

Catalytic Synthesis of N‐(5‐Methylfurfuryl)aniline from Bio‐Derived Carbohydrates

Xiao

Yang

et al. 2019

Asian J Org Chem

The value-added chemicals derived from lignocellulosic resources are mainly oxygen-containing compounds while nitrogen-containing compounds are also important in the industry and ambitiously desired to be obtained from bio-based carbohydrates. Here we report an efficient two-step approach from fructose under mild conditions to obtain N-(5-methylfurfuryl)aniline, a necessary nitrogenous intermediate for some important epoxyisoindoles which have good combat-Alzheimer's and antitumor biological activities. First, 5-methylfurfural was prepared with HI and H 3 PO 3 in a biphasic solution from fructose, then it was isolated and used for N-(5-methylfurfuryl)aniline synthesis through reductive amination catalyzed by a heterogeneous palladium catalyst. Besides, the substrate scope of the amines was examined, and most of them showed very good results. With this approach, renewable N-(5-methylfurfuryl)aniline was produced from fructose in an overall yield of 62%.[a] Dr.