The preclinical development of nanomedicines raises several challenges and requires a comprehensive characterization. Among them is the evaluation of the biodistribution following systemic administration. In previous work, the biocompatibility and in vitro targeting ability of a glycol chitosan (GC) based nanogel have been validated. In the present study, its biodistribution in the mice is assessed, using near‐infrared (NIR) fluorescence imaging as a tool to track the nanogel over time, after intravenous administration. Rapid whole body biodistribution of both Cy5.5 labeled GC nanogel and free polymer is found at early times. It remains widespreadly distributed in the body at least up to 6 h postinjection and its concentration then decreases drastically after 24 h. Nanogel blood circulation half‐life lies around 2 h with the free linear GC polymer presenting lower blood clearance rate. After 24 h, the blood NIR fluorescence intensity associated with both samples decreases to insignificant values. NIR imaging of the organs shows that the nanogel had a body clearance time of ≈48 h, because at this time point a weak signal of NIR fluorescence is observed only in the kidneys. Hereupon it can be concluded that the engineered GC nanogel has a fairly long blood circulation time, suitable for biomedical applications, namely, drug delivery, simultaneously allowing efficient and quick body clearance.
A rapid and simple procedure is reported for the determination of six ethylene glycol ethers in cleaning products and detergents using gas chromatography with mass spectrometry. The analytes were extracted from 2.0 g samples in acetonitrile (3 mL) and the extract was submitted to a clean‐up step by QuEChERS method, using a mixture containing 0.3 g magnesium sulfate, 0.15 g primary/secondary amine, and 0.05 g C18. The clean acetonitrile extract (1 μL) was injected into the chromatographic system. No matrix effect was observed, so the quantification of the samples was carried out against external standards. Detection limits were in the range 3.0–27 ng/g for the six ethylene glycol ethers. The recoveries obtained, using the optimized procedure, were in the 89.4–118% range, with relative standard deviations lower than 14%. Twenty‐three different household cleaning products, including glass cleaner, degreaser, floor, softeners, and clothes and dishwashing detergents, were analyzed. Large interindividual variations were observed between samples and compounds. 相似文献
Polyethylene glycol (PEG 200) was used as an eco-friendly plasticizer for preparing thermoplastic cellulose acetate (CA) by a twin-screw extruder. The plasticization efficiency of PEG 200 was compared with that of triethyl citrate (TEC). The interaction between polyethylene glycol and CA was investigated by Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). Both FT-IR and DSC proved that PEG 200 could form stable and strong hydrogen bonds with CA molecules. Scanning electron microscopy (SEM) revealed that the CA granules were completely disrupted during the extrusion and a continuous and homogeneous phase was observed. The PEG 200-plasticized cellulose acetate (PCA) showed greater viscosity reduction than TEC-plasticized cellulose acetate (TCA) at the same additive levels. Furthermore, the Izod-notched impact strength and elongation at break of PCA were higher than those of TCA. The tensile strength, Izod-notched impact strength and elongation at break of PCA containing 25 wt% PEG 200 reached 31.6 MPa, 20.9 KJ/m2 and 80.5%, respectively, as compared to 39.2 MPa, 10.9 KJ/m2 and 32.3% for 25 wt% TEC plasticized CA. 相似文献
In order to obtain cobalt oxides nanoparticles we have used the thermal decomposition of some carboxylate type precursors.
These precursors were obtained by the redox reaction between cobalt nitrate and ethylene glycol, either bulk or dispersed
in silica matrix. The redox reaction takes place by heating the Co(NO3)2·6H2O-C2H6O2 solution or the Si(OC2H5)4-Co(NO3)2·6H2O-C2H6O2 gels. Thermal analysis of the Co(NO3)2·6H2O-C2H6O2 solution and Si(OC2H5)-Co(NO3)2·6H2O-C2H6O2 gels allowed us to establish the optimal value for the synthesis temperature of the carboxylate precursors.
By fast heating of the solution Co(NO3)2·6H2O-C2H6O2, the redox reaction is immediately followed by the decomposition of the precursor, which represents an autocombustion process.
The product of this combustion contains CoO as unique phase. We have obtained a mixture of CoO and Co3O4 by annealing the synthesized carboxylate compounds for 2 h at 400°C. With longer annealing time (6 h), we have obtained Co3O4 as unique phase.
The XRD study of the crystalline phases resulted by thermal decomposition of the precursors embedded in silica matrix, showed
that the formation of Co2SiO4 and Co3O4, as unique phases, depends on the thermal treatment. 相似文献
The influence of hydroxymethyl chain length of the solvents on collagen was established with conformational stability and
thermal stability. Thermal stability of monomeric collagen and RTT fibres (rat tail tendon) treated with methanol, ethylene
glycol (EG) and glycerol were reported using the melting temperature for helix-coil transition and the peak temperature for
collagen-gelatin transition. Both melting temperature and peak temperature increases as the hydroxymethyl chain length increases.
Conformational stability of collagen solution treated with lower and higher concentrations of methanol, ethylene glycol and
glycerol indicates that aggregation of collagen molecule is more at higher concentrations of these solvents. The concentration
dependence is greater for the increased number of OH groups. Since protein aggregation is associated with neuro degenerative
diseases, aggregation of collagen molecule in the presence of solvents is of great importance for biomedical application. 相似文献
All genomic transactions in eukaryotes take place in the context of the nucleosome, the basic unit of chromatin, which is responsible for DNA compaction. Overcoming the steric hindrance that nucleosomes present for DNA‐processing enzymes requires significant conformational changes. The dynamics of these have been hard to resolve. Single‐pair Fluorescence Resonance Energy Transfer (spFRET) microscopy is a powerful technique for observing conformational dynamics of the nucleosome. Nucleosome immobilization allows the extension of observation times to a limit set only by photobleaching, and thus opens the possibility of studying processes occurring on timescales ranging from milliseconds to minutes. It is crucial however, that immobilization itself does not introduce artifacts in the dynamics. Here we report on various nucleosome immobilization strategies, such as single‐point attachment to polyethylene glycol (PEG) or surfaces coated with bovine serum albumin (BSA), and confinement in porous agarose or polyacrylamide gels. We compare the immobilization specificity and structural integrity of immobilized nucleosomes. A crosslinked star polyethylene glycol coating performs best with respect to tethering specificity and nucleosome integrity, and enables us to reproduce for the first time bulk nucleosome unwrapping kinetics in single nucleosomes without immobilization artifacts. 相似文献
A rapid method for determining diethylene glycol (DEG) in toothpaste based on the use of ultra-performance liquid chromatography
(UPLC) coupled to time-of-flight mass spectrometry (TOF-MS) has been developed. The method has been validated in toothpaste
samples spiked at different levels, 0.005, 0.1 and 5%, obtaining satisfactory recoveries (74–98%) and relative standard deviations
(<4%). Quantification was carried out by using matrix-matched standards calibration. The developed method was applied to several
types of toothpaste, making identification and quantification of DEG and other polyethylene glycols (PEG) feasible with very
little sample manipulation, as only extraction with water is required. The excellent sensitivity of TOF-MS analysis performed
in full-scan acquisition mode allowed the determination of DEG at concentration levels as low as 0.005% in samples and its
reliable identification via the mass accuracy measurements provided by this instrument (<5 ppm). 相似文献