| Summary: | 碩士 === 高雄醫學大學 === 香粧品學系碩士班 === 104 === Titanium dioxide nanomaterials offer superior protection for human skin against ultraviolet light. However, some literature reviews indicated that it might be associated with adverse effects such as cytotoxicity or reactive oxygen species (ROS) under UV-irradiation due to their nanoscale. The surface of carboxyfullerene is covered with π electrons constituting aromatic structures, which can effectively scavenge large amounts of radicals. Here, we used carboxyfullerene as radical scavenger for covering poor solubility of pristine fullerene. The aim of this study is to decorate fullerene - C70-carboxylic acid (C70-COOH) on the surface of titanium dioxide nanorods (TNR) and nanoparticles (P25) for the purpose of scavenging ROS during the UV-irradiation. The modified TiO2 composites were prepared through the esterification of C70-COOH with TNR (TNR/C70-COOH) and P25 (P25/C70-COOH). X-ray diffraction (XRD) pattern revealed that the synthesized TiO2 were rutile phase by hydrothermal process. Scanning electron microscope (SEM) patterns revealed that TiO2 of P25 composites are nanoparticles and TNR composites are major in nanorod with minor nanoparticles. EDS patterns showed that samples mixed with C70-COOH increase the ration of element C. Transmission electron microscope (TEM) patterns revealed that the surface of TiO2 coated with a layer of C70-COOH. Fourier transform infrared (FTIR) showed that the absorbance intensity around 1720 cm-1 is assigned to C=O stretching of C70-COOH. Thermogravimetric Analysis (TGA) patterns showed that the weight losses of TiO2/C70-COOH composites were correspond to the ratio of C70-COOH from 500-700 °C. In order to investigate scavenging radical ability of TiO2 composites, pyridoxine (Vit.B6), terephthalic acid (TA) and nitro blue tetrazolium (NBT) were chosen to react with singlet oxygen, hydroxyl radicals and superoxide ions, respectively. The results showed that both two types of TiO2 composites could reduce the singlet oxygen under the environment but only P25/C70-COOH revealed hydroxyl radicals and superoxide ions scavenging ability.
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