Materials for microencapsulation: what toroidal particles (“doughnuts”) can do better than spherical beads

Ungphaiboon, Suwipa; Attia, Dalia; d’Ayala, Giovanna Gomez; Sansongsak, P; Cellesi, Francesco; Tirelli, Nicola

doi:10.1039/c0sm00150c

Cited by 33 publications

(33 citation statements)

References 84 publications

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“…The nanoparticles dispersed in water at the concentration of 4 mg mL −1 and oxidized with 1 equivalent of NaOCl per thioether for 20 h at ambient temperature showed a significantly higher toxicity than the oxidation products of PPS with H 2 O 2 ; their IC50 value was in the range of 1 mg mL −1 (Figure 3SI, Supporting Information). It must be noted that these values are, however, not distant from those of polymers often considered to be rather biocompatible, such as chitosan 48…”

Section: Resultsmentioning

confidence: 95%

Oxidant‐Dependent REDOX Responsiveness of Polysulfides

Carampin

Lallana

Laliturai

et al. 2012

Macro Chemistry & Physics

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Poly(propylene sulfide) (PPS) is studied as an oxidation‐responsive macromolecular building block, in the perspective of anti‐inflammatory therapies. Here, we show that the nature of the oxidant has profound effects on the outcome of the oxidation process. PPS was exposed to hydrogen peroxide (H2O2) and hypochlorite (OCl−), which are oxidizing species commonly encountered during inflammatory processes. It was found that the oxidation with H2O2 converted thioethers into sulfoxides, producing water‐soluble macromolecular products with extremely low toxicity (L929 fibroblasts); on the contrary, the reaction with NaOCl produced sulfones in addition to sulfoxides, and this was accompanied by depolymerization, which appears to considerably affect the toxicity of the oxidation products.

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Section: Resultsmentioning

confidence: 95%

Oxidant‐Dependent REDOX Responsiveness of Polysulfides

Carampin

Lallana

Laliturai

et al. 2012

Macro Chemistry & Physics

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“…The shape of the chitosan microparticles was a result of the force balance of three‐phase interfacial tensions among the oil phase, water phase, and the chitosan droplets . As shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…, chitosan droplets are hemispherical shaped in the interface of TPP solutions, but will change to a disk form in CuSO 4 solutions. This phenomenon is attributed to the relatively high‐surface tension in TPP solutions and the relatively low‐surface tension in CuSO 4 solutions . Furthermore, a sufficiently rapid solidification freezes this morphology and loses recovery to a spherical morphology .…”

Section: Resultsmentioning

confidence: 99%

“…The proposed surface‐formation technique provides an alternative method for preparing nonspherical particles . It is based on spreading a polymer solution on an air/water surface followed by solidification of the polymer solution, and then the shape and size of the particles can be tailored by tuning the surface tension . This has the advantage of being simple and self‐assembling without any complex device or multistep operation procedure.…”

Section: Introductionmentioning

confidence: 99%

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Microfluidic‐assisted synthesis of hemispherical and discoidal chitosan microparticles at an oil/water interface

et al. 2012

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This study reports a facile method for the synthesis of hemispherical and discoidal chitosan microparticles by a combination of microfluidic technology and gelation strategy at an oil/water interface. Utilizing microfluidic emulsification in a cross-junction channel, the formation of regular droplets was achieved. Following the ionic gelation procedure at the liquid-liquid interface of the gelling solution and oil solution in the reservoir pool, either hemispherical or discoidal chitosan microparticles were obtained. Special emphasis was put on the interface reaction of emulsion gelation parameters such as ionic crosslinkers, density modifiers, and surfactants, to tailor the morphologies of chitosan particles ranging from 160 to 750 μm. In addition, the proposed microfluidic device is capable of generating relatively uniform microparticles with a well-controllable shape and size. Being a simple, low-cost and high-throughput process is an added advantage. The synthesized hemispherical and discoidal chitosan microparticles can be applied to many applications in the pharmaceutical and biomedical arena.

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“…Self-assembled NC framelike arrays are of particular interest due to their unusual optical, electrical, and mechanical properties, as a consequence of the large surface-to-volume ratios that can be attained. These emerging materials offer promise in a broad range of applications including drug delivery and therapeutics (18,(21)(22)(23), novel materials for catalysis (24), optics (18,21), photonics (22,23), and as nanopatterned scaffolds (25,26).…”

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confidence: 99%

Assembly of porous smectic structures formed from interlocking high-symmetry planar nanorings

Avendaño

Jackson

Müller

et al. 2016

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

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Materials comprising porous structures, often in the form of interconnected concave cavities, are typically assembled from convex molecular building blocks. The use of nanoparticles with a characteristic nonconvex shape provides a promising strategy to create new porous materials, an approach that has been recently used with cagelike molecules to form remarkable liquids with "scrabbled" porous cavities. Nonconvex mesogenic building blocks can be engineered to form unique self-assembled open structures with tunable porosity and long-range order that is intermediate between that of isotropic liquids and of crystalline solids. Here we propose the design of highly open liquid-crystalline structures from rigid nanorings with ellipsoidal and polygonal geometry. By exploiting the entropic ordering characteristics of athermal colloidal particles, we demonstrate that high-symmetry nonconvex rings with large internal cavities interlock within a 2D layered structure leading to the formation of distinctive liquid-crystalline smectic phases. We show that these smectic phases possess uniquely high free volumes of up to ∼ 95%, a value significantly larger than the 50% that is typically achievable with smectic phases formed by more conventional convex rod-or disklike mesogenic particles.nanorings | porous liquid crystals | self-assembly S elf-assembly of particles ranging in size from the nanometer to the micrometer scales can be used to fabricate structures in the mesoscale regime (1-5), otherwise difficult to achieve with traditional methods of chemical synthesis. Strategies to produce functional materials from the self-assembly of relatively simple nonspherical (anisotropic) building blocks have undergone unprecedented growth as a result of recent advances in experimental techniques to fashion colloidal and nanoparticles of arbitrary shape and well-defined sizes (6-9). An appealing feature of colloidal particles is that the repulsive and attractive contributions of the interaction between the particles can be modulated by controlling the properties of both the particle surface and the solvent medium to induce different types of forces, including short-range repulsions approaching hard-core (athermal) interactions (10).Colloidal particles are commonly represented using simplified coarse-grained convex geometries including ellipsoids, spherocylinders, polyhedra, and cut spheres (11, 12). The phase behavior of these convex models has been studied extensively by theory and simulation (13,14). Nonconvex (NC) models have received significantly less attention. NC particles offer new possibilities for the fabrication of functional materials as a result of the self-assembly of unique structures driven by interlocking and entanglement (15)(16)(17)(18)(19)(20). As featured in our current paper, NC rings can be packed into exotic highly open (low density) structures. Self-assembled NC framelike arrays are of particular interest due to their unusual optical, electrical, and mechanical properties, as a consequence of the large surface-to-...

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Materials for microencapsulation: what toroidal particles (“doughnuts”) can do better than spherical beads

Cited by 33 publications

References 84 publications

Oxidant‐Dependent REDOX Responsiveness of Polysulfides

Oxidant‐Dependent REDOX Responsiveness of Polysulfides

Microfluidic‐assisted synthesis of hemispherical and discoidal chitosan microparticles at an oil/water interface

Assembly of porous smectic structures formed from interlocking high-symmetry planar nanorings

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