Size dependent magnetic and antibacterial properties of solvothermally synthesized cuprous oxide (Cu2O) nanocubes

The smaller size Cu2O nanocubes can effectively increase the electrocatalytic active areas and subsequently promote electron transfer in the reduction of H2O2.

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Size-Dependent Bioactivity of Silver Nanoparticles: Antibacterial Properties, Influence on Copper Status in Mice, and Whole-Body Turnover

Nanotechnology Science and Applications ◽

10.2147/nsa.s287658 ◽

2020 ◽

Vol Volume 13 ◽

pp. 137-157

Author(s):

Ekaterina A Skomorokhova ◽

Tatiana P Sankova ◽

Iurii A Orlov ◽

Andrew N Savelev ◽

Daria N Magazenkova ◽

...

Keyword(s):

Silver Nanoparticles ◽

Antibacterial Properties ◽

Whole Body ◽

Size Dependent ◽

Copper Status

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Size-Dependent Cytotoxicity and Genotoxicity of Silver Nanoparticles in Cochlear Cells In Vitro

Journal of Nanomaterials ◽

10.1155/2019/6090259 ◽

2019 ◽

Vol 2019 ◽

pp. 1-12 ◽

Cited By ~ 15

Author(s):

Maria Perde-Schrepler ◽

Adrian Florea ◽

Ioana Brie ◽

Piroska Virag ◽

Eva Fischer-Fodor ◽

...

Keyword(s):

Silver Nanoparticles ◽

Comet Assay ◽

Otitis Media ◽

Cell Lines ◽

Antibacterial Properties ◽

Dna Lesions ◽

Attractive Alternative ◽

Ros Production ◽

Size Dependent

Silver nanoparticles (AgNPs) have been proven to have potent antibacterial properties, offering an attractive alternative to antibiotics in the treatment of several infections such as otitis media. Concerns have been raised though regarding their toxicity. There are few data regarding the toxic effects of AgNPs in cochlear cells. The aim of our study was to evaluate the effects of AgNPs of four sizes as a function of their size on HEI-OC1 cochlear cells and on HaCaT keratinocytes. The cells were treated with different concentrations of AgNPs. We evaluated silver uptake by atomic absorption spectroscopy and transmission electron microscopy (TEM), cytotoxicity with the alamarBlue test, ROS production with 2′,7′-dichloro-dihydro-fluorescein diacetate, and genotoxicity with the comet assay. Silver intracellular concentration increased proportionally with the incubation time and the size of the NPs. Silver uptake was higher in HEI-OC1 cells compared to HaCaT. While after 4 h exposure, only the 50 nm NPs were observed in both cell lines and only the 5 nm NPs were observed in the HaCaT cells, after 24 h, nanoparticles of all sizes could be visualized in both cell lines. The cells showed signs of distress: vacuolizations, autophagosomes, signs of apoptosis, or cellular debris. AgNPs of all sizes reduced viability proportionally with the concentration, HEI-OC1 cells being more affected. The toxicity of AgNPs decreased with the nanoparticle size, and ROS production was dose and size dependent, mainly in the cochlear cells. Genotoxicity assessed by comet assay revealed a higher level of DNA lesions in HEI-OC1 cells after treatment with small-sized AgNPs. The perspective of using AgNPs in the treatment of otitis media, although very attractive, must be regarded with caution: cochlear cells proved to be more sensitive to the toxic effect of AgNPs compared to other cell lines. Potential treatments must be tailored specifically, choosing NPs with minimum toxicity towards auditory cells.

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Size-Dependent Antibacterial Activity of Silver Nanoparticle-Loaded Graphene Oxide Nanosheets

Nanomaterials ◽

10.3390/nano10061207 ◽

2020 ◽

Vol 10 (6) ◽

pp. 1207 ◽

Cited By ~ 2

Author(s):

Thi Truong ◽

Selvaraj Kumar ◽

Yu-Tzu Huang ◽

Dave Chen ◽

Yu-Kuo Liu ◽

...

Keyword(s):

Antibacterial Activity ◽

Graphene Oxide ◽

Membrane Integrity ◽

Antibacterial Properties ◽

Ag Nps ◽

E Coli ◽

Size Dependent ◽

Transmission Electron ◽

Combined Action ◽

Bacterial Cell Membrane

A series of graphene oxide (GO) suspensions with different particle sizes (<100 nm, ~100 nm, ~1 µm and >1 µm) were successfully fabricated after 0, 30, 60 and 120 min of sonication, respectively. The antibacterial properties of GO suspensions showed that >1 µm GO size resulted in a loss of nearly 50% of bacterial viability, which was higher than treatment by ~100 nm GO size (25%) towards Escherichia coli (E. coli). Complete entrapment of bacteria by the larger GO was observed in transmission electron microscopy (TEM). Silver nanoparticles (Ag NPs) were doped onto GO samples with different lateral sizes to form GO–Ag NP composites. Resulting larger GO–Ag NPs showed higher antibacterial activity than smaller GO–Ag NPs. As observed by Fourier transform infrared spectroscopy (FTIR), the interaction between E. coli and GO occurred mainly at the outer membrane, where membrane amino acids interact with hydroxyl and epoxy groups. The reactive oxygen species (ROS) and the considerable penetration of released Ag+ into the inner bacterial cell membrane result in loss of membrane integrity and damaged morphology. The present work improves the combined action of GO size effect with constant Ag loadings for potential antibacterial activity.

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Synthesis of Antibacterial Oxide of Copper for Potential Application as Antifouling Agent

Current Nanoscience ◽

10.2174/1573413717666211118105842 ◽

2021 ◽

Vol 17 ◽

Author(s):

Neeru Bhagat ◽

Brajesh Pandey

Keyword(s):

Hybrid Method ◽

Cuprous Oxide ◽

Cupric Oxide ◽

Antibacterial Properties ◽

Copper Oxide Nanoparticles ◽

Precipitation Method ◽

Synthesis Of Nanoparticles ◽

Calcination Temperatures ◽

Antifouling Agent ◽

Moringa Oleifera Leaves

Background: Copper oxide nanoparticles have become very important due to their numerous applications and ease of synthesis. Out of the two oxides of copper, cuprous oxide exhibits better antibacterial, antimicrobial, and antifouling properties. Objective: The study aimed to find a way of synthesizing stable and eco-friendly oxide of copper and test it for antibacterial properties. Methods: The precipitation method was employed for the synthesis of nanoparticles. NaOH and Moringa Oleifera leaves extract were used as the reducing agents to obtain two different sets of samples. Results: Good phases of copper oxides were formed for all the samples (cuprous as well as cupric oxides). SEM studies showed that the structure of cupric oxide (CuO), formed at higher calcination temperatures, is well defined when synthesized using a hybrid method. Conclusion: Our studies indicate that the hybrid method of synthesis used by us is a more effective and quicker way of synthesizing cuprous oxide (Cu2O), which exhibits higher antibacterial properties as compared to cupric oxide (CuO).

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Production and STEM examination of controlled-size silver clusters

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100075488 ◽

1983 ◽

Vol 41 ◽

pp. 338-339

Author(s):

M. A. Listvan ◽

R. P. Andres

Keyword(s):

Cluster Size ◽

Metal Clusters ◽

Experimental Parameter ◽

Carbon Films ◽

Metal Species ◽

Silver Clusters ◽

Free Jet ◽

Size Dependent ◽

Cluster Properties ◽

Controllable Size

Knowledge of the function and structure of small metal clusters is one goal of research in catalysis. One important experimental parameter is cluster size. Ideally, one would like to produce metal clusters of regulated size in order to characterize size-dependent cluster properties.A source has been developed which is capable of producing microscopic metal clusters of controllable size (in the range 5-500 atoms) This source, the Multiple Expansion Cluster Source, with a Free Jet Deceleration Filter (MECS/FJDF) operates as follows. The bulk metal is heated in an oven to give controlled concentrations of monomer and dimer which were expanded sonically. These metal species were quenched and condensed in He and filtered to produce areosol particles of a controlled size as verified by mass spectrometer measurements. The clusters were caught on pre-mounted, clean carbon films. The grids were then transferred in air for microscopic examination. MECS/FJDF was used to produce two different sizes of silver clusters for this study: nominally Ag6 and Ag50.

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