Confinement of Reactive Oxygen Species in an Artificial-Enzyme-Based Hollow Structure To Eliminate Adverse Effects of Photocatalysis on UV Filters

Graphical Confine and eliminate : The integration of ZnO nanoparticles and CeO x nanoparticles into hollow microspheres (ZnO/CeO x HMS) could provide broad-spectrum UV protection and scavenge reactive oxygen species (ROS) generated under UV irradiation (see figure). Benefiting from the cooperative effect of the hollow structure and the antioxidative enzyme mimicking activity of CeO x , the generated ROS could be confined to the limited space and effectively scavenged. Skin cancers caused by UV irradiation have been a major public health problem. One simple and effective way to avoid the above detrimental effects is the use of UV-protective sunscreens. However, there has been considerable concern with the issue of the production of reactive oxygen species (ROS) through the photodegradation of commercial UV filters. Herein, for the first time, it is reported that the integration of ZnO nanoparticles and CeO x nanoparticles into hollow microspheres (ZnO/CeO x HMS) could provide broad-spectrum UV protection and scavenge generated ROS under UV irradiation. Benefiting from the cooperative effect of the hollow structure and the antioxidative activity of CeO x , ROS generated under UV irradiation could be confined to a limited space and effectively conversion into nontoxic molecules is catalyzed as a consequence of increased collision frequency. Therefore, both primary, direct UV-induced damage and secondary ROS toxicity could be greatly reduced.