| 1. |
- Nikonova, Olesya A, et al.
(författare)
-
Electrochemical Synthesis, Structural Characterization, and decomposition of Rhenium Oxoethoxide, Re4O4(OEt)12. Ligand Influence on the Structure and Bonding in the High-Valent Tetranuclear Planar Rhenium Alkoxide Clusters
- 2008
-
Ingår i: Inorganic Chemistry. ; 47, s. 1295-1300
-
Tidskriftsartikel (refereegranskat)abstract
- Anodic oxidation of rhenium in ethanol in the presence of LiCl as a conductive additive results with high yield information of a new oxoethoxide cluster, Re4O4(OEt)12. The structure of the planar centrosymmetric metal–oxygencore of this molecule is composed of four edge-sharing Re(V)O6 octahedra. Eight electrons are available for theformation of metal-metal bonds indicated by five relatively short Re-Re distances within the Re4-rhombus, a“planar butterfly” type cluster. The theoretical calculations are indicating relatively low contribution of metal-metalbonding in the stability of the core. The stability of the +V-oxidation state, unusual for rhenium alkoxides can beat least partially attributed to the size effects in the packing of ligands. The X-ray powder study indicates thattreatment of Re4O4(OEt)12 in ambient atmosphere rapidly transforms it into a mixed-valence derivativeRe4O6(OEt)10swith a structure related to the earlier investigated cluster Re4O6(OiPr)10. Thermal decomposition ofthe latter rhenium oxoethoxide results in reduction to rhenium metal at as low temperatures as 380 °C, producingaggregates of metal nanoparticles with the average size of 3 nm.
|
|
| 2. |
|
|
| 3. |
- Gaio, Servane, et al.
(författare)
-
Nanoceria-nanocellulose hybrid materials for delayed release of antibiotic and anti-inflammatory medicines
- 2022
-
Ingår i: Materials Advances. - : Royal Society of Chemistry. - 2633-5409. ; 3:19, s. 7228-7234
-
Tidskriftsartikel (refereegranskat)abstract
- A novel nanoceria-nanocellulose hybrid material has been developed and evaluated as a potential drug delivery system. Crystalline nanoceria was synthesized in situ in the nanocellulose to obtain a homogenous distribution without extensive particle aggregation. The hybrid materials were loaded with two antibiotic drugs, triclosan and ampicillin, and one anti-inflammatory drug, diclofenac. The bacteriostatic effect on the gram-negative bacteria Escherichia coli was evaluated for the hybrid materials containing triclosan and ampicillin. The nanoceria-nanocellulose hybrid displayed a better retention of ampicillin than triclosan in the disc diffusion test, which is likely due to the presence of the carboxylic acid group in ampicillin that has better affinity for ceria compared to the phenolic group in triclosan. However, drug release studies in solution revealed rapid release of ampicillin and diclofenac, indicative of outer-sphere complexes between ceria and the drugs.
|
|
| 4. |
- Galkina, Olga, et al.
(författare)
-
Antibacterial and photochemical properties of cellulose nanofiber-titania nanocomposites loaded with two different types of antibiotic medicines
- 2015
-
Ingår i: Journal of materials chemistry. B. - : Royal Society of Chemistry (RSC). - 2050-750X .- 2050-7518. ; 3:35, s. 7125-7134
-
Tidskriftsartikel (refereegranskat)abstract
- Nanocomposite dermal drug delivery systems based on cellulose nanofibers with grafted titania nanoparticles loaded by two antibiotic medicines from different classes, i.e. tetracycline (TC) and phosphomycin (Phos), were successfully produced by a "green chemistry'' approach in aqueous media. The influence of a different surface binding mechanism between the drug molecule and modified cellulose nanofibers on the release of the drug and, as a result, on antimicrobial properties against common pathogens Gram-positive, Staphylococcus aureus and Gram-negative Escherichia coli was investigated. The disk diffusion method and broth culture tests using varying concentrations of drugs loaded to nanocomposites were carried out to investigate the antibacterial effects. The influence of UV irradiation on the stability of the obtained nanocomposites and their antibacterial properties after irradiation were also investigated, showing enhanced stability especially for the TC loaded materials. These findings suggest that the obtained nanocomposites are promising materials for the development of potentially useful antimicrobial patches.
|
|
| 5. |
- Grau-Atienza, A., et al.
(författare)
-
Magnetically separable mesoporous Fe3O4/silica catalysts with very low Fe3O4 content
- 2016
-
Ingår i: Journal of Solid State Chemistry. - : Elsevier BV. - 0022-4596 .- 1095-726X. ; 237, s. 138-143
-
Tidskriftsartikel (refereegranskat)abstract
- Two magnetically separable Fe3O4/SiO2 (aerogel and MSU-X) composites with very low Fe3O4 content (< 1 wt%) have been successfully prepared at room temperature by co-condensation of MPTES-functionalized Fe3O4 nanoparticles (NPs) with a silicon alkoxide. This procedure yields a homogeneous incorporation of the Fe3O4 NPs on silica supports, leading to magnetic composites that can be easily recovered using an external magnetic field, despite their very low Fe3O4 NPs content (ca. 1 wt%). These novel hybrid Fe3O4/SiO2 materials have been tested for the oxidation reaction of 3,3',5,5'-tetramethylbenzidine (TMB) with hydrogen peroxide showing an enhancement of the stability of the NPs in the Fe3O4/silica aerogel as compared to the Fe3O4 NPs alone, even after five catalytic cycles, no leaching or agglomeration of the Fe3O4/SiO2 systems.
|
|
| 6. |
- Gupta, G., et al.
(författare)
-
Exploiting Mass Spectrometry to Unlock the Mechanism of Nanoparticle-Induced Inflammasome Activation
- 2023
-
Ingår i: Acs Nano. - : AMER CHEMICAL SOC. - 1936-0851 .- 1936-086X. ; 17:17, s. 17451-17467
-
Tidskriftsartikel (refereegranskat)abstract
- Nanoparticles (NPs) elicit sterile inflammation, but the underlying signaling pathways are poorly understood. Here, we report that human monocytes are particularly vulnerable to amorphous silica NPs, as evidenced by single-cell-based analysis of peripheral blood mononuclear cells using cytometry by time-of-flight (CyToF), while silane modification of the NPs mitigated their toxicity. Using human THP-1 cells as a model, we observed cellular internalization of silica NPs by nanoscale secondary ion mass spectrometry (nanoSIMS) and this was confirmed by transmission electron microscopy. Lipid droplet accumulation was also noted in the exposed cells. Furthermore, time-of-flight secondary ion mass spectrometry (ToF-SIMS) revealed specific changes in plasma membrane lipids, including phosphatidylcholine (PC) in silica NP-exposed cells, and subsequent studies suggested that lysophosphatidylcholine (LPC) acts as a cell autonomous signal for inflammasome activation in the absence of priming with a microbial ligand. Moreover, we found that silica NPs elicited NLRP3 inflammasome activation in monocytes, whereas cell death transpired through a non-apoptotic, lipid peroxidation-dependent mechanism. Together, these data further our understanding of the mechanism of sterile inflammation.
|
|
| 7. |
|
|
| 8. |
- Nilsson Ekdahl, Kristina, et al.
(författare)
-
Contact (kallikrein/kinin) system activation in whole human blood induced by low concentrations of α-Fe2O3 nanoparticles
- 2018
-
Ingår i: Nanomedicine. - : Elsevier. - 1549-9634 .- 1549-9642. ; 14:3, s. 735-744
-
Tidskriftsartikel (refereegranskat)abstract
- Iron-oxide nanoparticles (NPs) generated by environmental events are likely to represent health problems. α-Fe2O3 NPs were synthesized, characterized and tested in a model for toxicity utilizing human whole blood without added anticoagulant. MALDI-TOF of the corona was performed and activation markers for plasma cascade systems (complement, contact and coagulation systems), platelet consumption and release of growth factors, MPO, and chemokine/cytokines from blood cells were analyzed. The coronas formed on the pristine α-Fe2O3 NPs contained contact system proteins and they induced massive activation of the contact (kinin/kallikrein) system, as well as thrombin generation, platelet activation, and release of two pro-angiogeneic growth factors: platelet-derived growth factor and vascular endothelial growth factor, whereas complement activation was unaffected. The α-Fe2O3 NPs exhibited a noticeable toxicity, with kinin/kallikreinactivation, which may be associated with hypotension and long-term angiogenesis in vivo, with implications for cancer, arteriosclerosis and pulmonary disease.
|
|
| 9. |
|
|
| 10. |
- Seisenbaeva, Gulaim, et al.
(författare)
-
Mesoporous silica adsorbents modified with amino polycarboxylate ligands-functional characteristics, health and environmental effects
- 2021
-
Ingår i: Journal of Hazardous Materials. - : Elsevier BV. - 0304-3894 .- 1873-3336. ; 406
-
Tidskriftsartikel (refereegranskat)abstract
- A series of hybrid adsorbents were produced by surface modification with amino polycarboxylate ligands of industrially available microparticles (MP) of Kromasil (R) mesoporous nanostructured silica beads, bearing grafted amino propyl ligands. Produced materials, bearing covalently bonded functions as EDTA and TTHA, original Kromasil (R), bearing amino propyl ligands, and bare particles, obtained by thermal treatment of Kromasil (R) in air, were characterized by SEM-EDS, AFM, FTIR, TGA and gas sorption techniques. Adsorption kinetics and capacity of surface-modified particles to adsorb Rare Earth Elements (REE), crucial for extraction in recycling processes, were evaluated under dynamic conditions, revealing specificity matching the ligand nature and the size of REE cations. A detailed comparison with earlier reported adsorbents for REE extraction was presented. The cytotoxicity was assessed using four different types of healthy cells, human skeletal muscles derived cells (SKMDC), fibroblast cells, macrophage cells (RAW264.7), and human umbilical vein endothelial cells (HUVECs), indicating lower toxicity of ligand-free MP than MP bearing amino poly-carboxylate functions. Internalization of the MP inside the cells and release of nitric oxide were observed. In addition, zebrafish embryos were exposed to high concentrations of MP and did not show any pronounced toxicity.
|
|
| 11. |
- Spijksma, Gerald I., et al.
(författare)
-
The molecular composition of non-modified and acac-modified propoxide and butoxide precursors of zirconium and hafnium dioxides
- 2009
-
Ingår i: Journal of Sol-Gel Science and Technology. - : Springer Science and Business Media LLC. - 0928-0707 .- 1573-4846. ; 51:1, s. 10-22
-
Tidskriftsartikel (refereegranskat)abstract
- Long-term storage at 0 A degrees C of a paraffin-sealed flask with commercial 70 wt% solution of zirconium n-propoxide in n-propanol resulted in crystallization of an individual oxoalkoxide complex Zr(4)O(O(n)Pr)(14)((n)PrOH)(2) in over 20% yield. The structure of this molecule can be described as a triangular Zr(3)(mu(3)-O)(OR)(10)(ROH) core of 3 edge-sharing octahedrons with an additional Zr(OR)(4)(ROH) unit attached through a pair of (mu-OR) bridges. Mass spectrometric and (1)H NMR investigation of the commercial samples of the most broadly applied zirconium and hafnium n-propoxides and n-butoxides indicate the presence of analogous species in the commercial alkoxide precursors. The content of oxo-alkoxide species in the commercial precursors has been estimated to be similar to 20% for n-propoxide and similar to 35% for zirconium n-butoxide. A new route has been presented for synthesis of the individual crystalline mixed ligand precursor [Zr(O(n)Pr)(O(i)Pr)(3)((i)PrOH)](2), from zirconium n-propoxide. A high yield has been observed (similar to 90%), indicative of an almost complete precursor transformation. Mass spectrometry has shown that the synthesized mixed ligand precursor is dimeric, which makes it an attractive alternative to zirconium n-propoxide. Addition of 1 eq of Acetylacetone to zirconium or hafnium alkoxide precursors results in formation of dimeric [M(OR)(3)(acac)](2) in high yields. These species have limited stability (much higher for Hf than for Zr) and transform in solution into hydrolysis-insensitive M(acac)(4) through very unstable M(acac)(3)(OR) intermediates containing 7-coordinated metal centers. This transformation can be followed kinetically in hydrocarbon solvents by (1)H NMR and is noticeably accelerated by addition of parent alcohols. The obtained results clearly reveal limited applicability of EXAFS and XANES techniques for the study of such systems, especially in the context of structure prediction.
|
|
| 12. |
- Toprak, Muhammet S, 1973-, et al.
(författare)
-
ANNEX : Synthesis of Nanomaterials
- 2012
-
Ingår i: Adverse Effects of Engineered Nanoparticles. - : Academic Press. - 9780123869401
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
|
|
| 13. |
- Wilkinson, Kai, et al.
(författare)
-
Visualization of custom-tailored iron oxide nanoparticles chemistry, uptake, and toxicity
- 2012
-
Ingår i: Nanoscale. - 2040-3364. ; 4:23, s. 7383-7393
-
Tidskriftsartikel (refereegranskat)abstract
- Nanoparticles of iron oxide generated by wearing of vehicles have been modelled with a tailored solution of size-uniform engineered magnetite particles produced by the Bradley reaction, a solvothermal metal–organic approach rendering hydrophilic particles. The latter does not bear any pronounced surface charge in analogy with that originating from anthropogenic sources in the environment. Physicochemical properties of the nanoparticles were thoroughly characterized by a wide range of methods, including XPD, TEM, SEM, DLS and spectroscopic techniques. The magnetite nanoparticles were found to be sensitive for transformation into maghemite under ambient conditions. This process was clearly revealed by Raman spectroscopy for high surface energy magnetite particles containing minor impurities of the hydromaghemite phase and was followed by quantitative measurements with EXAFS spectroscopy. In order to assess the toxicological effects of the produced nanoparticles in humans, with and without surface modification with ATP (a model of bio-corona formed in alveolar liquid), a pathway of potential uptake and clearance was modelled with a sequence of in vitro studies using A549 lung epithelial cells, lymphocyte 221-B cells, and 293T embryonal kidney cells, respectively. Raman microscopy unambiguously showed that magnetite nanoparticles are internalized within the A549 cells after 24 h co-incubation, and that the ATP ligand is retained on the nanoparticles throughout the uptake process. The toxicity of the nanoparticles was estimated using confocal fluorescence microscopy and indicated no principal difference for unmodified and modified particles, but revealed considerably different biochemical responses. The IL-8 cytokine response was found to be significantly lower for the magnetite nanoparticles compared to TiO2, while an enhancement of ROS was observed, which was further increased for the ATP-modified nanoparticles, implicating involvement of the ATP signalling pathway in the epithelium.
|
|
