# Assessment of SiO2 Nanotube Activity to Modify DL α-Tocopherol via 1O2 Generation Under Visible Light Irradiation

## TL;DR

This study explores how SiO2 nanotubes and modified versions can generate singlet oxygen under visible light, which could be useful in biomedical applications.

## Contribution

The novelty lies in modifying SiO2 nanotubes with metallated porphyrin to enhance visible light-driven singlet oxygen generation.

## Key findings

- SiO2 nanotubes have a tubular morphology and high density of optically active defects.
- Porphyrin modification enhances light absorption and singlet oxygen generation.
- Singlet oxygen reactivity was evaluated using spectrofluorimetric analysis with DL α-Tocopherol.

## Abstract

This work investigates photoactive inorganic powders (SiO2, IrSiO2, and IrO2/IrSiO2) and their derivatives modified with metallated porphyrin, focusing on their ability to generate reactive oxygen species (ROS) under visible light exposure. The core material, SiO2, 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 (1O2) 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), N2 adsorption–desorption measurements, and zeta potential measurements.