Size and Optically Tunable Ethyl Cellulose Nanoparticles as Carriers for Organic UV Filters

Abstract Optically active nanoparticles (NPs) are potential building blocks for bottom‐up functional technology in applications such as displays, sensors, and sunscreens. For sunscreens in particular, NPs can be used as delivery systems for organic UV filters in order to minimise skin exposure to these molecules. Here, we investigate the synthesis of size‐tunable ethyl cellulose NPs (ECNPs) and their application as carriers for multiple organic UV filters. We prepared ECNPs with sizes of 50 to 165 nm via an antisolvent precipitation technique and investigate the incorporation of three commonplace organic UV filters – oxybenzone, avobenzone, and octinoxate – into the ECNPs. We found the particle loading varied greatly with each UV filter. Photodegradation of the UV filters remained unchanged upon incorporation into ECNPs and was not affected by co‐encapsulating the antioxidant α‐tocopherol. These results can significantly advance the development of environmentally friendly functionalized nanoparticles and UV‐protective coatings.