Kept in the dark : The non‐photocatalytic generation of free radicals from fine and ultrafine TiO2 particles has been studied by means of a spin‐trapping/ESR spectroscopy technique (see figure). The amount and kind of free radicals generated depends on the crystalline structure, but not on the particle dimensions.
The reaction of silyl enol ethers with β-nitroacrylates, in the presence of tetrabutyl ammonium fluoride as catalyst, allows the formation of polyfunctionalized β-nitro esters, or hexahydro-4H-benzoxazine-2-oxides, depending on the nature of the starting silyl enol ethers. 相似文献
Nanostructures displaying fluorescence and magnetic properties at the same time are potentially useful for achieving simultaneous bio‐separation and bio‐sensing (e.g., magnetic separation coupled with multiplexing optical detection of different tumour cell populations). Spherical nanobeads that display both fluorescent and magnetic features are reported; they are fabricated by grafting fluorescent oligothiophene molecules to an amphiphilic polymer that is then used to enwrap iron oxide nanoparticles, which acts as the magnetic domain. By tuning experimental conditions, control over the number of magnetic nanoparticles per bead and over the bead diameter (30–400 nm) was achieved. A cell separation efficiency of the level required for cell sorting applications is also reported.
In our search for thiophene fluorophores that can overcome the limits of currently available organic dyes in live-cell staining, we synthesized biocompatible dithienothiophene-S,S-dioxide derivatives (DTTOs) that were spontaneously taken up by live mouse embryonic fibroblasts and HeLa cells. Upon treatment with DTTOs, the cells secreted nanostructured fluorescent fibrils, while cell viability remained unaltered. Comparison with the behavior of other cell-permeant, newly synthesized thiophene fluorophores showed that the formation of fluorescent fibrils was peculiar to DTTO dyes. Laser scanning confocal microscopy of the fluorescent fibrils showed that most of them were characterized by helical supramolecular organization. Electrophoretic analysis and theoretical calculations suggested that the DTTOs were selectively recognized by the HyPro component of procollagen polypeptide chains and incorporated through the formation of multiple H-bondings. 相似文献
The ability of a hydrogel obtained by crosslinking INUDV and PEGBa to facilitate sustained release of flutamide is examined. The hydrogel is prepared in pH = 7.4 PBS and no toxic solvents or catalysts are used. It is recovered in microparticulate form and its size distribution is determined. Mucoadhesive properties are evaluated in vitro by reproducing gastrointestinal conditions. Flutamide is loaded into the hydrogel using a post‐fabrication encapsulation procedure that allows a drug loading comparable to that of market tablets. Drug‐loaded microparticles are orally administered to cross‐bred dogs and the in vivo study demonstrates their ability to prolong the half‐life of the principal active metabolite approximately threefold and to significantly increase its bioavailability.
The efficient internalization of TGF‐beta inhibitor‐loaded polyelectrolyte capsules and particles is studied in two HCC cell lines. Two polyelectrolyte pairs (biocompatible but not degradable and biodegradable crosslinked with gluteraldehyde) are employed for coating. The capsules are characterized by SEM. LY is successfully loaded inside the core and embedded between polymer layers. MS is used to quantify the loading efficiency by comparing post‐loading and core‐loading methods, since both coated templates and hollow shells are used as carriers. CLSM confirms dissolution of the pre‐formed multilayer upon enzymatic degradation as the method of release, and migration assays demonstrate a higher inhibition efficiency of TGF‐beta in tailored biodegradable capsules compared to free LY administration.
The levels of 22 phthalate diesters (phthalates) and organophosphate triesters (organophosphates) have been investigated in
standard reference material 2585 (SRM 2585) “organic contaminants in house dust.” Ultrasonic-assisted solvent extraction and
solid-phase extraction on a Florisil adsorbent were used as the extraction and cleanup steps combined with analysis using
gas chromatography–tandem mass spectrometry in positive ion chemical ionization mode. Seven phthalates were detected in the
concentration range 1–570 μg/g. Di(2-ethylhexyl) phthalate was the major phthalate present at 570 μg/g. Ten organophosphates
were detected in SRM 2585. Tris(2-butoxyethyl) phosphate was the predominant organophosphate at 82 μg/g, and nine organophosphates
were determined at concentrations ranging from 0.19 to 2.3 μg/g. Five organophosphates were below the method detection limit,
of which two were in level with the procedural blank. The applied extraction and cleanup method was evaluated for the analysis
of SRM 2585. The extraction yield was ≥99%, except for tris(2-chloroethyl) phosphate (97%) and diethyl phthalate (98.5%).
The problem of calibration curvature is addressed, and it is shown that the use of deuterated standards improves the analysis.
The concentrations of ten organophosphate esters were determined in SRM 2585, and seven of these were compared with existing
data. To our knowledge, this is the first report of the levels of the seven phthalates esters in SRM 2585 “organic contaminants
in house dust.” 相似文献