we have prepared Mg doped ceria nanostructures, and characterized by LCR meter for electrical conductivity, at low frequencies the electric conductivity is almost same for all Mg dopant levels but electrical conductivity increases at higher frequencies with higher doping level of Mg.
and with increase in electrical conductivity in high Mg dopant level, Reactive oxygen species (ROS) is also increased, can anybody explain what could be the possible reason for it?
You need to specify what ROS you are referring to. The variety of ROS is enormous, so is their reactivity, some are oxidants, some reductands, all are produced by different systems with spatiotemporal specificity. For more details, see, for instance:
Article Thioredoxins, Glutaredoxins, and Peroxiredoxins-Molecular Me...
Hi, Asmat, very interesting question, indeed. Please, consider that ROS is a results of impaired electron transport through membrane. That's why electrical conductivity may directly relate with generation of the ROS, mainly ROS what produced at the plasma membrane. But conductivity may not have relation with ROS what generate on mitochondria during respiration. You should also take into account that redox potential and ROS is different, so, you can not link redox potential to conductivity direct.
Dear Asmat
It is known that much of ceria’s useful properties can be linked to the presence of oxygen vacancies. The formation of neutral oxygen vacancies in ceria involves a reversible change in the oxidation state of two cerium ions from Ce(IV) to Ce(III).
This means that an oxygen ion, formally O2− (which is among the ROS) leaves the lattice and the two electrons left behind in the process get trapped at two cerium sites, i.e. they become localized at two cerium sites. At such cerium sites, the electron occupies an otherwise empty Ce4f -state and this could explain the increase in conductivity through the formation of oxygen vacancies (and consequently of the ROS) especially in higher frequencies.
Finally it should be noted that f-electron localization in ceria can arise not only when oxygen vacancies are formed, but also by an aliovalent electron-donating dopant (Mg in your case) which also contributes in increased conductivity.
Maria
You may clarify your issues by consulting:
Journal of Biophysical Chemistry
Vol.2 No.4(2011), Article ID:8424,4 pages DOI:10.4236/jbpc.2011.24053
Variations induced in human erythrocytes by ultra-low X-ray doses
Samera M. Sallam
Free Radic Biol Med. 1994 Apr;16(4):477-84.
Properties of cardiac I(leak) induced by photosensitizer-generated reactive oxygen.
Tarr M, Arriaga E, Goertz KK, Valenzeno DP.
BioMed Research International
Volume 2013 (2013), Article ID 942916, 15 pages
http://dx.doi.org/10.1155/2013/942916
Review Article
Mechanisms of Nanoparticle-Induced Oxidative Stress and Toxicity
Amruta Manke, Liying Wang, Yon Rojanasakul
1. Electrical conductivity depends on the concentration of electrolytes. The concentrations of electrolytes in cells are about 0.1 l/mole (Cl-, NO2-, etc.) Superoxide concentration (the only radical-ion in ROS) is about 10-11 l/mole. So, how can ROS influence conductivity? 2. Mg is an intransitive metal, therefore it cannot reduce oxygen to superoxide.
Professor Afanas'ev
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