Copper Oxide Nanoparticles Are Highly Toxic: A Comparison between Metal Oxide Nanoparticles and Carbon Nanotubes

2008 ◽  
Vol 21 (9) ◽  
pp. 1726-1732 ◽  
Author(s):  
Hanna L. Karlsson ◽  
Pontus Cronholm ◽  
Johanna Gustafsson ◽  
Lennart Möller
2021 ◽  
Vol 12 (3) ◽  
pp. 1803-1807
Author(s):  
Anil Kumar S ◽  
Ramesh A

Gastric ulcer is an excavation of mucosa and extending to submucosal layers due to increased gastric secretion, generation of free radicals and imbalance between protective factors and aggravating factors. The present study aimed to screen yttrium and copper oxide nanoparticles for antiulcerogenic activity. Metal oxide nanoparticles were evaluated for various biological activities considering their high surface area to volume ratio, different oxidative states, cell permeability etc. Various studies have proved metal oxide nanoparticles to be beneficial in various ailments due to their antioxidant, antibacterial, and other pharmacological activities. Nanoparticles prepared using biogenic methods were relatively more biocompatible and less toxic compared to conventional methods of synthesis. In the present study, green synthesized yttrium and copper oxide nanoparticles were evaluated for acute toxicity, antioxidant, proton pump inhibition and antiulcerogenic activity. In vitro antioxidant activity by DPPH, nitric oxide scavenging methods and H+K+ATPase assay was performed to evaluate the mechanism of action. Synthesized nanoparticles have shown no signs of acute toxicity as per OECD 423. Pyloric ligation method was performed to evaluate gastric volume, pH and ulcer severity. The present study revealed the dose-dependent antiulcer potential of yttrium oxide nanoparticles at doses of 2mg/kg and 20mg/kg. Antisecretory action of yttrium and copper oxides were evident from in vitro H+K+ATPase activity and inhibition of gastric volume. Antioxidant activities of yttrium oxide nanoparticles indicate gastric mucosal protection by free radical scavenging action. Copper oxide nanoparticles produced antisecretory activity but produced mucosal damage and hemorrhage at a dose of 20mg/kg.


ACS Nano ◽  
2014 ◽  
Vol 8 (11) ◽  
pp. 11290-11304 ◽  
Author(s):  
Xiaojie Liu ◽  
Iris Marangon ◽  
Georgian Melinte ◽  
Claire Wilhelm ◽  
Cécilia Ménard-Moyon ◽  
...  

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1882
Author(s):  
Jin Ah Lee ◽  
Won Jun Lee ◽  
Joonwon Lim ◽  
Sang Ouk Kim

Metal oxide nanoparticles supported on heteroatom-doped graphitic surfaces have been pursued for several decades for a wide spectrum of applications. Despite extensive research on functional metal oxide nanoparticle/doped carbon nanomaterial hybrids, the role of the heteroatom dopant in the hybridization process of doped carbon nanomaterials has been overlooked. Here, the direct growth of MnOx and RuOx nanoparticles in nitrogen (N)-doped sites of carbon nanotubes (NCNTs) is presented. The quaternary nitrogen (NQ) sites of CNTs actively participate in the nucleation and growth of the metal nanoparticles. The evenly distributed NQ nucleation sites mediate the generation of uniformly dispersed <10 nm diameter MnOx and RuOx nanoparticles, directly decorated on NCNT surfaces. The electrochemical performance of the resultant hybridized materials was evaluated using cyclic voltammetry. This novel hybridization method using the dopant-mediated nucleation and growth of metal oxides suggests ways that heteroatom dopants can be utilized to optimize the structure, interface and corresponding properties of graphitic carbon-based hybrid materials.


2008 ◽  
Vol 92 (2) ◽  
pp. 023110 ◽  
Author(s):  
Jesse Wensel ◽  
Brian Wright ◽  
Dustin Thomas ◽  
Wayne Douglas ◽  
Bert Mannhalter ◽  
...  

2008 ◽  
Vol 8 (7) ◽  
pp. 3333-3342
Author(s):  
D. Barreca ◽  
W. J. Blau ◽  
F. C. Dillon ◽  
J. D. Holmes ◽  
C. Kufazvinei ◽  
...  

Metal oxide-based nanoparticles of cobalt or nickel were deposited inside the pores and on the surface of hexagonal mesoporous silicas by a direct synthesis technique using Pluronic P85 and P123 surfactants as structure directing agents with the appropriate metal phthalocyanine as a metal precursor. Metal loadings were between 0.4–3.2 wt.%. XPS studies showed that the initial form of the metal oxide nanoparticles were [CoO] and [NiO] respectively. Samples of these materials formed from the P85 surfactant and 3.0 wt.% were used to grow carbon nanotubes (CNTs) from acetylene feedstock in a catalytic chemical vapour deposition (CCVD) reactor at 800 °C. CNT growth appeared to be random and the CNTs had diameters ranging from <10 to >90 nm. Treatment of the metal impregnated silicas with nitric acid produced materials which, under the same CNT growth conditions, afforded more uniform CNTs with diameters between 5–15 nm. No significant loss in mesophase ordering was seen in the TEM, PXRD or nitrogen physisorption analysis of the acid washed samples. CNTs grown with cobalt impregnated silicas formed with the P123 surfactant had diameters in the range 15–25 nm. Raman spectroscopy of the CNT products showed the nanotubes were highly graphitised and of good quality.


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