Search results for "capsules"
showing 10 items of 103 documents
Magnetic polyorganosiloxane core–shell nanoparticles: Synthesis, characterization and magnetic fractionation
2010
Abstact Here, we present the synthesis, characterization and magnetic separation of magnetic polyorganosiloxane nanoparticles. Magnetic iron oxide nanoparticles with average particle radii of 3.2 nm had been synthesized by a simple coprecipitation process of iron(II) and iron(III) salt in basic solution. Afterwards, the particles were successfully incorporated into a polyorganosiloxane network via a polycondensation reaction of trimethoxymethylsilane (T), diethoxydimethylsilane (D) and the functional monomer (chloromethylphenyl)trimethoxysilane (ClBz-T) in aqueous dispersion. A core–shell system was chosen to increase the flexibility of the system concerning size, composition and functional…
Versatile preparation of silica nanocapsules for biomedical applications
2020
Core–shell nanocapsules are receiving increasing interest for drug delivery applications. Silica nanocapsules have been the focus of intensive studies due to their biocompatibility, versatile silica chemistry, and tunable porosity. However, a versatile one-step preparation of silica nanocapsules with well-defined core–shell structure, tunable size, flexible interior loading, and tailored shell composition, permeability, and surface functionalization for site-specific drug release and therapeutic tracking remains a challenge. Herein, an interfacially confined sol–gel process in miniemulsion for the one-step versatile preparation of functional silica nanocapsules is developed. Uniform nanocap…
LbL multilayer capsules: recent progress and future outlook for their use in life sciences.
2010
In this review we provide an overview of the recent progress in designing composite polymer capsules based on the Layer-by-Layer (LbL) technology demonstrated so far in material science, focusing on their potential applications in medicine, drug delivery and catalysis. The benefits and limits of current systems are discussed and the perspectives on emerging strategies for designing novel classes of therapeutic vehicles are highlighted. © 2010 The Royal Society of Chemistry.
Nanofibrous photocatalysts from electrospun nanocapsules
2017
We present the design of multicompartment metal oxide/silica nanofibrous photocatalysts by colloid-electrospinning and subsequent calcination. During the calcination process, silica nanomaterials are cemented to form the fibrous framework and metal oxide precursors are crystallized inside and onto the fibers. This multicompartment nanofibrous structure, constructed with nanoparticles and core-shell nanocapsules, is therefore beneficial for the separation of the materials and the light utilization due to the multiple reflections and scattering of incident light in the cavities. The photocatalytic activity of the fibers was verified by the successful degradation of a model dye rhodamine B. Th…
Temperature Sensing in Cells Using Polymeric Upconversion Nanocapsules
2020
Monitoring local temperature inside cells is crucial when interpreting biological activities as enhanced cellular metabolism leads to higher heat production and is commonly correlated with the presence of diseases such as cancer. In this study, we report on polymeric upconversion nanocapsules for potential use as local nanothermometers in cells by exploiting the temperature dependence of the triplet-triplet annihilation upconversion phenomenon. Nanocapsules synthesized by the miniemulsion solvent evaporation technique are composed of a polymer shell and a liquid core of rice bran oil, hosting triplet-triplet annihilation upconversion active dyes as sensitizer and emitter molecules. The sens…
Silica-coated calcium pectinate beads for colonic drug delivery
2013
The aim of this work is to develop novel organic-inorganic hybrid beads for colonic drug delivery. For this purpose, calcium pectinate beads with theophylline are prepared by a cross-linking reaction between amidated low-methoxyl pectin and calcium ions. The beads are then covered with silica, starting from tetraethyoxysilane (TEOS), by a sol-gel process. The influence of TEOS concentration (0.25, 0.50, 0.75 and 1.00 M) during the process is studied in order to modulate the thickness of the silica layer around the pectinate beads and thus to control the drug release. The interactions between the silica coating and the organic beads are weak according to the physicochemical characterizations…
Immunogenicity and reactogenicity of HbOC vaccine administered simultaneously with acellular pertussis vaccine (DTaP) into either arms or thighs of i…
1997
To evaluate the reactogenicity and immunogenicity of a Haemophilus influenzae type b conjugate vaccine (HbOC) and of a tricomponent acellular pertussis vaccine (DTaP) when injected simultaneously into either contralateral arms or into contralateral thighs, 110 infants were enrolled to receive three doses of DTaP at 3, 4, and 5 months and two HbOC doses at 3 and 5 months of age. Administration of either of the two vaccines into arms was associated with significantly more local side effects than administration into thighs. There was no difference in geometric mean concentration (GMC) values for any of the four vaccine antigens between subjects who had been vaccinated into arms or thighs. Afte…
A self-assembled M8L6 cubic cage that selectively encapsulates large aromatic guests.
2011
Porphyrins cubed: A series of self-assembled M8L6 cubic cages that enclose a volume in excess of 1300 A3 were synthesized (see scheme). The porphyrinic walls of the cubes provide favorable sites for pnp interactions, leading to selectivity between large and chemically similar aromatic guests: three molecules of coronene are incorporated and the higher fullerenes C70nC84 are selectively bound in the presence of
The structure of Yersinia pestis Caf1 polymer in free and adjuvant bound states
2010
Caf1 of the plague bacterium, Yersinia pestis is a polymeric virulence factor and vaccine component, formed from monomers by a donor strand exchange (DSE) mechanism. Here, EM images of Caf1 reveal flexible polymers up to 1.5 microm long (4MDa). The bead-like structures along the polymer are 5.8 + or - 1 nm long and correspond to single Caf1 proteins. Short polymers often form circles, presumably by DSE. We also provide the first images of proteins bound to alhydrogel adjuvant. Caf1, hemocyanin and anthrax PA are all resolved clearly and Caf1 exhibits adjuvant bound stretches with long intervening loops draped from the edges.
Reasons for the exclusive formation of heterodimeric capsules between tetra-tolyl and tetra-tosylurea calix[4]arenes
2007
The selective heterodimerization of tetra-tolyl (1a) and tetra-tosylurea (1b) calixarenes, serendipitously found by Rebek et al. (R. K. Castellano, B. H. Kim and J. Rebek, Jr., J. Am. Chem. Soc., 1997, 119, 12671–12672), has been used for the construction of highly sophisticated macrocycles and well-defined supramolecular assemblies. Regrettably, hitherto, neither the exact structure of these heterodimers nor the reason for their exclusive formation is known. We present molecular dynamics simulations using the AMBER force field in explicit chloroform solvent for the two homodimers, the heterodimer and the two uncomplexed tetra-urea calixarenes. The rigid rotation about the C–S–N–C bond of t…