As mentioned above, these oxide NPs are harmful in part because both anatase and rutile forms are semiconductors and produce ROS. Particularly, P25 kind has band-gap energies estimated of 3.2 and 3.0 eV, equivalent to radiation wavelengths of approximately 388 and 414 nm, respectively. Irradiation at these wavelengths or below produces a separation of charge, resulting in a hole in the valence band and a free electron in the conduction band, due to the electron movement from the valence to conduction bands. These hole–electron pairs generate ROS when they interact with H₂O or O₂ [43,44]. It was described that they can cause an increase in ROS levels after exposure to UV-visible light [45]. The NBT assay in the studied samples showed that bare P25TiO₂NPs produce a large amount of ROS, which is drastically reduced by functionalization with vitamin B2 (Fig. 5). This vitamin, also known as riboflavin, was discovered in 1872 as a yellow fluorescent pigment, [46] but its function as an essential vitamin for humans was established more than sixty years later, and its antioxidant capacity was not studied until the end of the XX century [47,48]. This antioxidant role in cells is partially explained because the glutathione reductase enzyme (GR) requires it for good functionality. This enzyme is the one in charge of the conversion of oxidized glutathione to its reduced form which acts as a powerful inner antioxidant and can quench the ROS [49,50]. The cost of this action is that the glutathione is converted to the oxidized form and needs to be recovered by the GR. Consequently, the cells need more vitamin B2. Another glutathione action is the protection against hydroperoxide. This activity is also mediated by riboflavin. Therefore, local delivery of this vitamin seems to significantly help the cells in their fight to keep the oxidative balance, once they are exposed to high levels of ROS.

In recent years, titanium dioxide (TiO2) has gained immense popularity across various industries due to its excellent properties, such as high opacity, brightness, and ultraviolet light absorption. As a result, the demand for titanium dioxide has increased significantly, prompting a surge in the number of manufacturers hoping to capitalize on this booming market. While quality remains a priority, cost-effectiveness has emerged as a crucial factor for consumers, leading to a growing interest in cheap titanium dioxide manufacturers.

The RGB LED panel was made ad hoc, and configured for solar simulation white light (including the absorption spectra of the nanoparticles: 390–410). No heat was detected at the working distance. The retina of the albino male Wistar rats were not affected under these conditions, because the intensity and time of the applied irradiation was lower than the regular fluorescent lamp bulb in the room (216.65 W/m2) [34].

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