Assessment of SiO(2) Nanotube Activity to Modify DL α-Tocopherol via (1)O(2) Generation Under Visible Light Irradiation.

This work investigates photoactive inorganic powders (SiO(2), IrSiO(2), and IrO(2)/IrSiO(2)) and their derivatives modified with metallated porphyrin, focusing on their ability to generate reactive oxygen species (ROS) under visible light exposure. The core material, SiO(2), exhibits a tubular morphology and a high density of optically active defects. Modifiers such as metallic and iridium oxide nanoparticles, along with porphyrin, are employed to enhance light absorption and the generation of singlet oxygen ((1)O(2)) for potential biomedical applications. The time-dependent photogeneration of singlet oxygen is monitored using a Singlet Oxygen Green Sensor (SOSG), and its reactivity is evaluated in relation to DL α-Tocopherol through a spectrofluorimetric analysis. The photoactive materials, both before and after porphyrin modification, are characterized using Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), X-ray Diffraction (XRD), X-ray Fluorescence (XRF), UV-Vis Spectroscopy, X-ray Photoelectron Spectroscopy (XPS), N(2) adsorption-desorption measurements, and zeta potential measurements.