High-pressure freezing/freeze substitution and transmission electron microscopy for characterization of metal oxide nanoparticles within sunscreens

Nanomedicine ◽  
2012 ◽  
Vol 7 (4) ◽  
pp. 541-551 ◽  
Author(s):  
Margaret K Butler ◽  
Tarl W Prow ◽  
Ya-Nan Guo ◽  
Lynlee L Lin ◽  
Richard I Webb ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Pressure ◽  
Metal Oxide ◽  
Metal Oxide Nanoparticles ◽  
Freeze Substitution ◽  
Oxide Nanoparticles ◽  
High Pressure Freezing ◽  
Transmission Electron

scholarly journals Mixture Effects of Diesel Exhaust and Metal Oxide Nanoparticles in Human Lung A549 Cells

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1302 ◽  
Author(s):  
Zerboni ◽  
Bengalli ◽  
Baeri ◽  
Fiandra ◽  
Catelani ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Metal Oxide ◽  
Diesel Exhaust ◽  
Human Lung ◽  
Metal Oxide Nanoparticles ◽  
A549 Cells ◽  
Oxide Nanoparticles ◽  
Transmission Electron ◽  
Exhaust Particles

Airborne ultrafine particles (UFP) mainly derive from combustion sources (e.g., diesel exhaust particles—DEP), abrasion sources (non-exhaust particles) or from the unintentional release of engineered nanoparticles (e.g., metal oxide nanoparticles—NPs), determining human exposure to UFP mixtures. The aim of the present study was to analyse the combined in vitro effects of DEP and metal oxide NPs (ZnO, CuO) on human lung A549 cells. The mixtures and the relative single NPs (DEP, ZnO, CuO) were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS) and inductively coupled plasma-optic emission spectroscopy (ICP-OES). Cells were exposed for different times (3–72 h) to mixtures of standard DEP at a subcytotoxic concentration and ZnO and CuO at increasing concentrations. At the end of the exposure, the cytotoxicity was assessed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) and clonogenic tests, the pro-inflammatory potential was evaluated by interleukin-8 (IL-8) release and the cell morphology was investigated by fluorescence and transmission electron microscopy. The obtained results suggest that the presence of DEP may introduce new physico-chemical interactions able to increase the cytotoxicity of ZnO and to reduce that of CuO NPs.

Ultrastructure of the host-parasite interaction in leaves of Duchesnea indica infected by the rust fungus Frommeëla mexicana var. indicae as revealed by high pressure freezing

2001 ◽  
Vol 79 (1) ◽  
pp. 49-57 ◽  
Author(s):  
C W Mims ◽  
C Rodriguez-Lother ◽  
E A Richardson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Pressure ◽  
Rust Fungus ◽  
Freeze Substitution ◽  
Transfer Cells ◽  
Host Cells ◽  
High Pressure Freezing ◽  
Transmission Electron ◽  
Duchesnea Indica

A combination of scanning and transmission electron microscopy was used to examine the host-pathogen relationship in leaves of Duchesnea indica (Andrz) Focke infected by the rust fungus Frommeëla mexicana var. indicae McCain & Hennen. Samples for transmission electron microscopy were prepared using high pressure freezing followed by freeze substitution. This protocol provided excellent preservation of both host cells and fungal haustoria. Each haustorium of F. mexicana var. indicae possessed a long slender neck with a neck band and an expanded body that contained two nuclei positioned close together. The haustorial body was lobed and sometimes even branched but lacked septa. Details of the extrahaustorial membrane that separated each haustorium from the cytoplasm of its host cell were particularly well preserved. Extensive labyrinth cell wall ingrowths developed around haustorial necks, as well as elsewhere, in infected cells. These ingrowths appeared to be identical to those present in plant transfer cells. Transfer cells are thought to be involved in intensive solute transfer over short distances. This appears to be the first report of the development of transfer cells in response to infection by a plant pathogenic fungus.Key words: haustoria, transfer cells, freeze substitution, electron microscopy.

Magnetic Nanocomposite Aerogels

2011 ◽  
Vol 1306 ◽  
Author(s):  
Anna Corrias ◽  
Danilo Loche ◽  
Maria F. Casula
Keyword(s):  
Metal Oxide ◽  
Metal Oxide Nanoparticles ◽  
Sol Gel ◽  
Structural Features ◽  
Oxide Nanoparticles ◽  
X Ray ◽  
Nanoparticle Agglomeration ◽  
Transmission Electron ◽  
Average Size

ABSTRACTAerogels are regarded as ideal candidates for the design of functional nanocomposites containing supported metal or metal oxide nanoparticles. The large specific surface area together with the open pore structure enables aerogels to effectively host finely dispersed nanoparticles up to the desired loading, to provide nanoparticle accessibility and/or to prevent nanoparticle agglomeration, as required to supply their specific functionalities.The preparation of highly porous nanocomposite aerogels containing magnetic metal, alloy or metal oxide nanoparticles dispersed into amorphous silica, with high purity and homogeneity, was successfully achieved by a novel sol-gel procedure involving urea-assisted co-gelation of the precursor phases. This method allows fast gelation, giving rise to aerogels with 97% porosity, and it is very versatile allowing to vary composition, loading and average size of the nanoparticles.The characterization of the morphological and structural features of the nanocomposite aerogels is carried out using different techniques, such as X-ray diffraction, Transmission Electron Microscopy and X-ray Absorption Spectroscopy. The characterization of the magnetic properties is carried out by SQUID magnetometry.

Preparation, Characterization of N-Ti-MCM-22 Molecular Sieve and its Photocatalytic Properties

2012 ◽  
Vol 602-604 ◽  
pp. 205-208
Author(s):  
Yue Cheng ◽  
Xiao Yuan Su
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Methylene Blue ◽  
High Pressure ◽  
Liquid Phase ◽  
Molecular Sieve ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

Nanocrystalline N-doped and Ti-containing MCM-22 catalyst was synthesized by the static hydrothermal method, using sodium azide as nitrogen source for doping, and tetra-n-butyl titanate [Ti(OC4H9)4] as precursors of TiO2. The catalysts were characterized by X-ray diffraction, transmission electron microscopy, and energy-dispersive spectroscopy.During liquid phase photocatalytic degradation of methylene blue (MB) under high-pressure Hg arc lamp irradiation, the asprepared N-doped Ti-MCM-22 exhibited much higher activity than the undoped Ti-MCM-22, attributed to the effect of nitrogen dopant.

High-pressure freezing and freeze substitution fixation of the plant pathogenic fungus Exobasidium vaccinii

1996 ◽  
Vol 54 ◽  
pp. 78-79
Author(s):  
Elizabeth A. Richardson ◽  
Charles W. Mims
Keyword(s):  
Electron Microscopy ◽  
High Pressure ◽  
Plant Pathogens ◽  
Pathogenic Fungus ◽  
Freeze Substitution ◽  
High Pressure Freezing ◽  
Large Samples ◽  
Reproductive Structures ◽  
Transmission Electron ◽  
Fungal Genus

Members of the small fungal genus Exobasidium are all plant pathogens. Most species are noted for their ability to produce large fleshy galls on leaves and flower parts. They produce their hyphae and specialized absorbing structures known as haustoria inside these galls and their sexual reproductive structures (basidia) on gall surfaces. The objective of this study was to examine the feasibility of using high pressure freezing (HPF) followed by freeze-substitution (FS) fixation to prepare Exobasidium induced galls on Rhododendron sp. for study with transmission electron microscopy (TEM). HPF fixation followed by FS fixation is considered to be the best method for preserving large samples of plant tissue for TEM. This approach has shown promise for the examination of host-pathogen relationships in fungal diseases of plants.

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