The production of ROS was studied on white blood cells as a model to screen the effect on eukaryotic cells after being exposed to samples and solar simulated irradiation (according to the level of penetration under the skin). For that purpose, the leukocytes were separated from anticoagulated fresh blood using the Ficoll-Hypaque reactive in a well-known technique [33]. Then, 50 μL of suspensions of P25TiO2NPs (0.2 mg/mL and 0.02 mg/mL), vitaminB2@P25TiO2NPs (0.2 mg/mL and 0.02 mg/mL) and vitamin B2 (0.2 mg/mL and 0.02 mg/mL) were prepared and mixed with 50 μL of white blood cells suspension. A solution of 3% H2O2 was used as positive control and PBS as negative control. Then, the samples were irradiated using the LED panel for 3 and 6 h to simulate the light penetration into the skin. Also, a set of samples was kept in the dark as control. Finally, the ROS were detected through the colorimetric assay employing the nitroblue tetrazolium salt (NBT salt) and the absorbance at 650 nm was measured. The experiment was reproduced twice; the standard deviation was calculated and p-value < 0.05 were considered significant.
The principal natural source of titanium dioxide is mined ilmenite ore, which contains 45-60 percent TiO2. From this, or an enriched derivative (known as titanium slag), pure TiO2 can be produced using the sulphate or chloride process.
Rebecca Capua is an assistant conservator in the Paper Conservation Department at the Metropolitan Museum of Art since 2009. She received an MA in art history and an Advanced Certificate in art conservation from the Conservation Center, Institute of Fine Arts, New York University in 2007. Her primary area of research is on the materials of American artists of the late 19th and early 20th century. Address: The Sherman Fairchild Center for the Conservation of Works on Paper, Metropolitan Museum of Art, 1000 Fifth Avenue, New York, NY 10028. Email: rebecca.capua@metmuseum.org.
CAS: 1345-05-7