Concerning nanotechnological consumer products, the most rapidly growing is the use of nanoparticles (NPs).(47) So far the knowledge regarding the safety aspects of NPs is still in its initial phase and greater efforts is needed to understand the interaction of NPs with the human body. (48) Several studies have reported that NPs always showed more serious toxicity than bulks and suggested that their size and the dose were the key factors influencing NPs toxic effects.(49) Despite of this, large numbers of products containing NPs are commercially available, including sunscreens, cosmetics, foods, fertilizers and medical equipment. (50)
Zinc oxide nanoparticles (ZnO NPs) are known to be one of the most important metal oxide nanomaterials …show more content…
Large amounts of ROS could be generated even when only small amounts of ZnO NPs are incorporated into cells. (62) ZnO NPs with its high reactive activity are able to interact with biomolecules due to their small size and large specific surface area. [30] (63) During this process, chemical reactions take place and leads to ROS accumulation and OS [60]. (64,65) Another potential mechanism involves the generation of ROS is by NPs themselves and depends on their physicochemical characteristics that lead to spontaneous generation of ROS at their surface. (66) [5] Another important features of ZnO NPs which play a critical role in determining their mechanism of ROS generation is particle size. Nanoparticles of smaller size may induce OS by disturbing the balance between oxidant and anti-oxidant processes. [107] …show more content…
These can react with biological molecules (DNA, proteins, and lipids) leading to oxidative damage. (68) [33] Another source of ROS generation is cytochrome P450 enzymes (P450s) where the metabolism of ZnO NPs by P450 cytochrome is another possible source of ROS [60]. (65) reeeppp Normally, cells are equipped with a variety of antioxidants that serve to counterbalance the effect of oxidants including; superoxide dismutase (SOD) catalase, Glutathione peroxidase (GSH-Px) and Glutathione GSH. (69) [201] Imbalance in the ROS production and antioxidant defense system results in interference with normal cellular processes and causing cell death. [21]. (33 rep introd) In addition, it was confirmed that ZnO NPs exhibited a dose-dependent decreasing catalase and SOD levels causing intracellular accumulation of ROS. As levels of ROS exceeded the capacity of cellular antioxidants, the antioxidant system could not eliminate them. [33] (68) [69] (70) This might explain the more severe damage observed in the animals given the higher dose of ZnO
Zinc oxide nanoparticles (ZnO NPs) are known to be one of the most important metal oxide nanomaterials …show more content…
Large amounts of ROS could be generated even when only small amounts of ZnO NPs are incorporated into cells. (62) ZnO NPs with its high reactive activity are able to interact with biomolecules due to their small size and large specific surface area. [30] (63) During this process, chemical reactions take place and leads to ROS accumulation and OS [60]. (64,65) Another potential mechanism involves the generation of ROS is by NPs themselves and depends on their physicochemical characteristics that lead to spontaneous generation of ROS at their surface. (66) [5] Another important features of ZnO NPs which play a critical role in determining their mechanism of ROS generation is particle size. Nanoparticles of smaller size may induce OS by disturbing the balance between oxidant and anti-oxidant processes. [107] …show more content…
These can react with biological molecules (DNA, proteins, and lipids) leading to oxidative damage. (68) [33] Another source of ROS generation is cytochrome P450 enzymes (P450s) where the metabolism of ZnO NPs by P450 cytochrome is another possible source of ROS [60]. (65) reeeppp Normally, cells are equipped with a variety of antioxidants that serve to counterbalance the effect of oxidants including; superoxide dismutase (SOD) catalase, Glutathione peroxidase (GSH-Px) and Glutathione GSH. (69) [201] Imbalance in the ROS production and antioxidant defense system results in interference with normal cellular processes and causing cell death. [21]. (33 rep introd) In addition, it was confirmed that ZnO NPs exhibited a dose-dependent decreasing catalase and SOD levels causing intracellular accumulation of ROS. As levels of ROS exceeded the capacity of cellular antioxidants, the antioxidant system could not eliminate them. [33] (68) [69] (70) This might explain the more severe damage observed in the animals given the higher dose of ZnO