china nano titanium dioxide

The lack of clear regulations and controls explains that P25TiO2NPs are still found in many of the commercialized sunscreens in the market. Some of them are coated to reduce the photoactivity of the anatase form, which is known to be responsible for tissue damage, but not enough studies were made on these coated forms. The anatase photoactivity could trigger the production of reactive oxygen species (ROS) generation, as it was stated before. The ROS are chemically reactive species containing oxygen, such as peroxides, superoxide, hydroxyl radical, and singlet oxygen. They are regularly produced in the biological milieu and counterbalanced by physiological antioxidant defense mechanisms. However, an abrupt increase of ROS may result in non-reversible damage to the skin cells. The effects of coated and uncoated P25TiO2NPs need therefore to be studied, and articles on this topic present different conclusions. [11][12][13] Recent literature on this topic found that TiO2NPs inhalation provokes serious genotoxicity and DNA damage [14][15][16][17]. On the other hand, some studies in rats have reported no significant harm to genetic material [18][19][20][21][22].

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Titanium alloy is widely used as a biomaterial due to its superior biocompatibility, mechanical properties close to human bones, and enhanced corrosion resistance. These properties have made the alloys suitable for use in a wide spectrum of biomedical applications including artificial bones, artificial joints, dental roots, and medical devices. The excellent performance of titanium alloy is mainly due to the oxide film as shown in Figure 1 [1]. The functional composition of the oxide film is mainly titanium dioxide (TiO2). Titanium dioxide has good biocompatibility, stable chemical property, and low solubility in water, which prevents substrate metal ions from dissolution. Furthermore, it also improves the wear and fatigue resistance of implants in the human body.

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