scholarly journals Preparation, Characterization, and Cytotoxicity of Various Chitosan Nanoparticles

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Qian Yao ◽  
Wei Liu ◽  
Xiao-Jun Gou ◽  
Xiao-Qiang Guo ◽  
Jun Yan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Biological Activity ◽  
Hepg2 Cells ◽  
Drug Loading ◽  
Chitosan Nanoparticles ◽  
Inhibitory Effect ◽  
Hepatic Carcinoma ◽  
Transmission Electron ◽  
Diverse Biological Activity

Chitosan nanoparticles (CS-NPs) without drug loading have diverse biological activity. In this study, we prepared CS-NPs, CS-NPs solidified by different amount of glutaraldehyde, and CS-NPs modified with either biotin (B-CS-NPs) or biotin and avidin (A-B-CS-NPs) and examined their cytotoxicity on HepG2 cells. The morphology and size were measured by transmission electron microscopy and photon correction spectroscopy, respectively. The extent of solidification was validated by the approach of sonication. Biotin connect density on the surface of B-CS-NPs and A-B-CS-NPs was determined by biotin assay kit. The results showed that most of the NPs were round and their mean sizes were all below 300 nm. Biotin connect density of B-CS-NPs and A-B-CS-NPs was 2.18 ± 0.36 and 1.26 ± 0.11 mol biotin/mol CS, respectively. At relatively low concentration, CS-NPs with higher extent of solidification exhibited more vigorous inhibitory effect against HepG2 cells than those without solidification. When NPs were incubated with cancer cells for 48 h, compared with CS-NPs, the anticancer activity of B-CS-NPs and A-B-CS-NPs was enhanced significantly(P<0.05). In addition, A-B-CS-NPs showed superior cytotoxicity over B-CS-NPs. This study demonstrates that modification with biotin and avidin may be an efficient way in improving antitumor activity of CS-NPs against hepatic carcinoma.

scholarly journals Clusterin in Alzheimer’s Disease: An Amyloidogenic Inhibitor of Amyloid Formation

2021 ◽  
Author(s):  
Panagiotis M. Spatharas ◽  
Georgia I. Nasi ◽  
Paraskevi L. Tsiolaki ◽  
Marilena K. Theodoropoulou ◽  
Nikos C. Papandreou ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fluorescence Emission ◽  
Inhibitory Effect ◽  
Fibril Formation ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Ft Ir ◽  
Dynamics Simulations ◽  
Peptide Analogues

Abstract Background: Clusterin is a heterodimeric glycoprotein (α- and β-chain), which has been described as an extracellular molecular chaperone. In humans, clusterin is an amyloid associated protein, co-localizing with fibrillar deposits in Alzheimer’s disease. To clarify its implication in the disease, we provide evidence that clusterin has intrinsic amyloidogenic properties, which are intertwined with its inhibitory effect on amyloid-β fibril formation.Methods: Aggregation-prone regions of human clusterin were predicted by AMYLPRED. Synthetic peptide-analogues of each region underwent in vitro aggregation assays, namely, examination with transmission electron microscopy, X-Ray diffraction from oriented fibers, ATR FT-IR spectroscopy, and Congo Red birefringence assays. The same peptide-analogues were co-incubated with amyloid-β and their potential as inhibitors was tested with thioflavin T fluorescence emission measurements and transmission electron microscopy. Molecular dynamics simulations were performed to gain insight into the interaction between amyloid-β and the peptide-analogues.Results: Clusterin peptide-analogues form amyloid-like fibrils, as revealed by transmission electron microscopy. They can form fibers that give cross-β X-ray diffraction patterns and ATR FT-IR spectroscopy confirms the dominance of β-strand secondary structure. They also exhibit apple-green birefringence, when stained with Congo Red and examined between crossed polars of a polarizing light microscope. Furthermore, when amyloid-β is co-incubated with clusterin’s peptide analogues, it shows decreased thioflavin T fluorescence emission over time, while the formation of amyloid-β amyloid fibrils is diminished, as confirmed by transmission electron microscopy. The inhibitory effect of clusterin-peptide analogues on amyloid-β fibril formation was ascertained though molecular dynamics simulations. Conclusions: Clusterin has multiple aggregation-prone regions in its α-chain and these regions have a functional role in the inhibition of amyloid-β fibril formation.

scholarly journals Effection of cordycepin on Inhibition proliferation by activating autophagy in HepG2 cell

2020 ◽  
Vol 189 ◽  
pp. 02026
Author(s):  
Li Tianjiao ◽  
Cheng Bijun ◽  
Li Fenglin
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Proliferation ◽  
Hepg2 Cells ◽  
Active Component ◽  
Liver Tumors ◽  
Biological Activities ◽  
Related Protein ◽  
Immunofluorescence Method ◽  
Transmission Electron

Cordycepin, the main active component of Cordyceps militaris, possesses a variety of biological activities. This paper investigated the inhibition of cordycepin on liver tumors. HepG2 cells were treated with cordycepin. The inhibition rates of cell proliferation was detected by MTT, LC3 protein was detected by immunofluorescence method, autophagy was observed by transmission electron microscopy, autophagy related protein was detected by Western blot. The results showed that cordycepin significantly inhibited the proliferation of HepG2 cells, and significantly increased the expression level of LC3 protein (<0.05). and the autophagy increased in the cells. The Atg-related protein analysis showed that cordycepin significantly reduced the p-mTOR / β-actin ratio and p62 / β-actin ratio (<0.01), and significantly increased the LC3II/LC3I ratio (P<0.01). The results suggested that cordycepin inhibited the proliferation by activating autophagy in HepG2 cells.

scholarly journals Transmission electron microscopy of the benzbromarone-induced change in mitochondrial morphology in HepG2 cells

2019 ◽  
Vol 6 (8) ◽  
pp. 281-286 ◽  
Author(s):  
Tomoyuki Sato ◽  
Akinori Takemura ◽  
Yugo Ikeyama ◽  
Yuriko Sakamaki ◽  
Ayako Mimata ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Hepg2 Cells ◽  
Mitochondrial Morphology ◽  
Transmission Electron

Effects of Cymbopogon nardus (L.) W. Watson essential oil on the growth and morphogenesis of Aspergillus niger

2001 ◽  
Vol 47 (1) ◽  
pp. 9-17 ◽  
Author(s):  
Virginia G de Billerbeck ◽  
Christine G Roques ◽  
Jean-Marie Bessière ◽  
Jean-Louis Fonvieille ◽  
Robert Dargent
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aspergillus Niger ◽  
Essential Oil ◽  
Normal Growth ◽  
Inhibitory Effect ◽  
Mycelium Growth ◽  
Cymbopogon Nardus ◽  
Transmission Electron ◽  
Hyphal Diameter

The growth inhibitory effect of Cymbopogon nardus (L.) W. Watson var. nardus essential oil on Aspergillus niger (Van Tieghem) mycelium was determined on agar medium. The mycelium growth was completely inhibited at 800 mg/L. This concentration was found to be lethal under the test conditions. Essential oil at 400 mg/L caused growth inhibition of 80% after 4 days of incubation, and a delay in conidiation of 4 days compared with the control. Microscopic observations were carried out to determine the ultrastructural modifications of A. niger hyphae after treatment with C. nardus essential oil. The main change observed by transmission electron microscopy concerned the hyphal diameter and the hyphal wall, which appeared markedly thinner. These modifications in cytological structure might be caused by the interference of the essential oil with the enzymes responsible for wall synthesis which disturb normal growth. Moreover, the essential oil caused plasma membrane disruption and mitochondrial structure disorganization. The findings thus indicate the possibility of exploiting Cymbopogon nardus essential oil as an effective inhibitor of biodegrading and storage-contaminating fungi.Key words: essential oil, antifungal agent, hyphal ultrastructure, cell wall, scanning electron microscopy, transmission electron microscopy.

scholarly journals Preparation and Characterization of Folate Targeting Magnetic Nanomedicine Loaded with Cisplatin

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Minqiang Xie ◽  
Yiming Xu ◽  
Jie Liu ◽  
Tao Zhang ◽  
Hongzheng Zhang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Water Solubility ◽  
Folate Receptor ◽  
Drug Loading ◽  
Hydroxyl Group ◽  
Transmission Electron ◽  
Scattering Phase

We used Aldehyde sodium alginate (ASA) as modifier to improve surfactivity and stability of magnetic nanoparticles, and folate acid (FA) as targeting molecule. Fe3O4nanoparticles were prepared by chemical coprecipitation method. FA was activated and coupled with diaminopolyethylene glycol (NH2-PEG-NH2). ASA was combined with Fe3O4nanoparticles, and FA-PEG was connected with ASA by Schiff’s base formation. Then Cl-in cisplatin was replaced by hydroxyl group in ASA, and FA- and ASA-modified cisplatin-loaded magnetic nanomedicine (CDDP-FA-ASA-MNPs) was prepared. This nanomedicine was characterized by transmission electron microscopy, dynamic lighterring scattering, phase analysis light scattering and vibrating sample magnetometer. The uptake of magnetic nanomedicine by nasopharyngeal and laryngeal carcinoma cells with folate receptor positive or negative expression were observed by Prussian blue iron stain and transmission electron microscopy. We found that CDDP-FA-ASA-MNPs have good water-solubility and stability. Mean diameter of Fe3O4core was 8.17 ± 0.24 nm, hydrodynamic diameters was110.90±1.70 nm, and zeta potential was-26.45±1.26 mV. Maximum saturation magnetization was 22.20 emu/g. CDDP encapsulation efficiency was49.05±1.58% (mg/mg), and drug loading property was14.31±0.49% (mg/mg). In vitro, CDDP-FA-ASA-MNPs were selectively taken up by HNE-1 cells and Hep-2 cells, which express folate receptor positively.

Techniques for Transmission Electron Microscopy of Fiber-Matrix Interfaces in Aluminum Alloy-Boron Composites by Ion Erosio

1971 ◽  
Vol 29 ◽  
pp. 204-205
Author(s):  
G. G. Shaw
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aluminum Alloy ◽  
Electron Beam ◽  
Pure Aluminum ◽  
Ion Milling ◽  
Transmission Electron ◽  
Fiber Matrix ◽  
Ion Erosion ◽  
Row Of Fibers

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.

Direct Observation of Heat Exchanger Deposits by Cross Sectioning

1967 ◽  
Vol 25 ◽  
pp. 364-365
Author(s):  
R. W. Anderson ◽  
D. L. Senecal
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heat Exchanger ◽  
Direct Observation ◽  
Cross Sections ◽  
Preparation Method ◽  
Specimen Preparation ◽  
Flowing Water ◽  
Transmission Electron ◽  
Deposit Layer

A problem was presented to observe the packing densities of deposits of sub-micron corrosion product particles. The deposits were 5-100 mils thick and had formed on the inside surfaces of 3/8 inch diameter Zircaloy-2 heat exchanger tubes. The particles were iron oxides deposited from flowing water and consequently were only weakly bonded. Particular care was required during handling to preserve the original formations of the deposits. The specimen preparation method described below allowed direct observation of cross sections of the deposit layers by transmission electron microscopy.The specimens were short sections of the tubes (about 3 inches long) that were carefully cut from the systems. The insides of the tube sections were first coated with a thin layer of a fluid epoxy resin by dipping. This coating served to impregnate the deposit layer as well as to protect the layer if subsequent handling were required.

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

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