Engineered fabrication of EGCG-UV absorber conjugated nano-assemblies for antioxidative sunscreens with broad-band absorption

Applying sunscreen is a common, convenient, and effective measure to protect skin from ultraviolet (UV) damage, but most of UV absorbers in the present commercially available sunscreens are accompanied with the insufficiencies in terms of efficacy and biosafety. The use of nanotechnology to combine conventional UV absorbers with biocompatible natural products is a feasible strategy to combat these deficiencies. Herein, a simple, green and engineering preparation of broad-band sunscreens was demonstrated by the molecular assembly of a UV absorber aminobenzoic acid (ABA) and polyphenol extracted from green tea (EGCG). Spherical and negatively-charged EGCG/ABA nanoparticles (EA NPs) were simply synthesized with a wide range of particle size from 54.6 to 715.1 nm. These NPs had the satisfactory biocompatibility and antioxidative activity, and could protect fibroblasts from oxidative-stress damage. The formulations containing 10 wt% EA NPs further exhibited broad-spectrum UV absorption and lower UV transmittance than commercial sunscreens. It is believed that this study would spur the utilization of natural reproducible sources for developing biosafe sunscreens with strong anti-UV capability. Indeed, this simple nanotechnology aimed at tackling the biosafe risk of conventional UV absorbers provides a feasible solution strategy with green tea extracts. [Display omitted] •Molecular assembly of UV absorbers and tea polyphenol was demonstrated.•Colloidally stable nano-assemblies had a broad-spectrum UV absorption capacity.•The nano-assemblies could protect fibroblast from oxidative-stress damage.•The formulations exhibited better UV photoprotection than commercial sunscreens.