Carboxyfullerene decorated titanium dioxide nanomaterials for reactive oxygen species scavenging activities

Titanium dioxide nanomaterials offer superior protection for human skin against ultraviolet light. However, some reports have indicated that they might be associated with adverse effects such as cytotoxicity or reactive oxygen species (ROS) under UV-irradiation due to their nanoscale size. The surfaces of fullerenes are covered with π electrons, constituting aromatic structures, which can effectively scavenge large amounts of radicals. Unfortunately, their poor solubility in water, severe aggregation, and toxicity in biological applications when dispersed in solvent have imposed limitations on the use of fullerenes. Herein, we used carboxyfullerene as a radical scavenger to improve poor solubility. The modified materials were prepared through the esterification of C₇₀-COOH with TNR (TNR/C₇₀-COOH) and P25 (P25/C₇₀-COOH). The structures and the properties were analyzed by using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and high-resolution transmission electron microscopy (HRTEM). In order to investigate the scavenging radical abilities of TiO₂ composites, pyridoxine (Vit. B6), nitroblue tetrazolium (NBT) and terephthalic acid (TA) were chosen to react with singlet oxygen, superoxide ions and hydroxyl radicals, respectively. The results show that both types of TiO₂ composites could reduce the ROS in the environment and exhibit great potential in anti-oxidative and anti-inflammation applications.