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Hollow Capsules (hollow + capsule)
Selected AbstractsChemo-Enzymatic Synthesis of Raffinose-Branched Polyelectrolytes and Self-Assembly Application in Microcapsules,MACROMOLECULAR BIOSCIENCE, Issue 1 2006Qi Wu Abstract Summary: A novel biocompatible polyelectrolyte poly(vinyl raffinose- co -acrylic acid) (PRCA) containing a raffinose branch was prepared via redox polymerization using Fe2+/K2S2O8/H2O2 starting from enzymatically-synthesized monomer: 1- O -vinyldecanedioyl raffinose. Copolymers with different monomer feed ratios were prepared and characterized with IR, NMR, and GPC. PRCA can be alternated with polycation to form microcapsules on a crystals template by electrostatic layer-by-layer technique. The multilayers of PRCA/poly(methacryloyloxyethyl dimethylbenzyl ammonium chloride) (PMBA) on quartz slides and PRCA/poly(dimethyldiallyl ammonium chloride) (PDDA) on acyclovir crystals template were fabricated and characterized with UV-Vis spectra, the microelectrophoretic measurement, and TEM. Hollow capsules can be formed after the removal of acyclovir crystals template in a buffer solution. The nano-capsule-carrying galactose residue is a potential targeting drug-controlled delivery systems. Synthesis of PRCA and TEM image of a hollow (PRCA/PDDA)10 capsule. [source] Pseudobilayer Vesicle Formation via Layer-by-Layer Assembly of Hydrophobically Modified Polymers on Sacrificial Substrates,ADVANCED FUNCTIONAL MATERIALS, Issue 7 2005J. Khopade Abstract A bilayer of a hydrophobically modified polyelectrolyte, octadecyl poly(acrylamide) (PAAm), sandwiched between the layers of a hydrophilic polyelectrolyte, poly(ethyleneimine) (PEI), is prepared by the sequential electrostatic,hydrophobic,electrostatic-interaction-driven self-assembly on planar and colloid substrates. This process results in a PEI/[PAAm]2/PEI-multilayer-coated substrate. The removal of a PAA/PEI/[PAAm]2/PEI-multilayer-coated decomposable colloidal template produces hollow capsules. Irregular hydrophobic domains of the [PAAm]2 bilayer in the PEI/[PAAm]2/PEI-multilayer capsule are infiltrated with a lipid to obtain a uniform, distinct hydrophobic layer, imparting the capsule with a pseudobilayer vesicle structure. [source] Magnetic Janus Particles Prepared by a Flame Synthetic Approach: Synthesis, Characterizations and PropertiesADVANCED MATERIALS, Issue 2 2009Nan Zhao Spherical Janus particles consisting of ,-Fe2O3 and SiO2 bicompartments are effectively prepared through a flame synthetic route. The excellent colloidal stability of these particles offers versatile choices for further manipulating them to form different types of assembled structures. As an example, the synthesis of hollow capsules with a magnetic core and a soft Au/PVP-film shell is demosntrated. [source] From Hollow to Dense Spheres: Control of Dipolar Interactions by Tailoring the Architecture in Colloidal Aggregates of Superparamagnetic Iron Oxide Nanocrystals,ADVANCED MATERIALS, Issue 6 2004P. Tartaj The synthesis of spherical colloidal aggregates (see Figure) of superparamagnetic iron oxide nanocrystals with different packing fractions is reported. Using a mean-field model, the magnitude of dipolar interactions between nanomagnets has been correlated with differences in their assembly. The results could help understanding of the magnetic behavior of magnetic liposomes and hollow capsules, which are promising for drug delivery. [source] Hollow polylactide microcapsules with controlled morphology and thermal and mechanical propertiesAICHE JOURNAL, Issue 11 2009Hassan Sawalha Abstract Hollow polylactide microcapsules were prepared by multistage premix membrane emulsification of polylactide/dichloromethane/oil solutions in water (nonsolvent). The effects of the different oils on the morphology, thermal, and mechanical properties of the hollow microcapsules were investigated. All oils resulted in hollow microcapsules with controlled shell thickness of ,60 nm except for eugenol, in which irregular, massive capsules were obtained. The properties of the microcapsules were strongly dependent on the oil used, for example the thermal transition temperatures found for hollow capsules were lower than for solid particles prepared without any oil. The crystallinity and transition temperatures of the capsules prepared with linear alkanes were higher than for cyclic alkanes; terpenes gave the lowest transition temperatures. The shell stiffness, measured with atomic force microscopy, was highly dependent on the oil used. Capsules prepared with dodecane showed higher stiffness (3.3 N m,1) than with limonene (2 N m,1) or cyclohexane (1.4 N m,1). © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Design and in vitro Biodegradation of Novel Hepatocyte-Targetable (Galactose Polycation/Hemoglobin) Multilayers and MicrocapsulesMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 12 2009Fu Zhang Abstract The formation of novel hepatocyte-targetable and biodegradable polycation/protein multilayers and hollow microcapsules by LbL assembly is reported, in which galactose residues allow for targetability and Hb acts as a main degradable component. The in vitro biodegradability of multilayers via proteases was evaluated in detail on both planar substrates and CaCO3 particles followed by UV-Vis, SEM, and AFM characterizations. The degradation approximately follows an exponential decay, and the relation between the kinetic constant k and the number n of deposited bilayers is well approximated by a power equation. Sustained release of the encapsulated model drug was attained by using enzymatic degradation of hollow capsules. [source] Design of a Microfluidic System to Investigate the Mechanical Properties of Layer-by-Layer Fabricated CapsulesMACROMOLECULAR MATERIALS & ENGINEERING, Issue 12 2003Michelle Prevot Abstract A microfluidic system was designed, fabricated and implemented to study the behavior of polyelectrolyte capsules flowing in microscale channels. The device contains microchannels that lead into constrictions intended to capture polyelectrolyte microcapsules which were fabricated with the well-known layer-by-layer (LbL) assembly technique. The behavior of hollow capsules at the constrictions was visualized and the properties of the capsules were investigated before and after introduction into the device. Time series of video frames showing capsules being compressed into a constriction. [source] | ||||||||||||||||||||||