Zinc-metal–organic frameworks with tunable UV diffuse-reflectance as sunscreens

Abstract

Abstract Background UV exposure continues to induce many health issues, though commercial sunscreens are available. Novel UV filters with high safety and efficacy are urgently needed. Metal–organic frameworks (MOFs) could be a suitable platform for UV filter development, due to their tunable optical, electrical, and photoelectric properties by precise controlled synthesis. Results Herein, four zinc-based MOFs with various bandgap energies were chose to investigate their optical behaviors and evaluate their possibility as sunscreens. Zeolitic imidazolate framework-8 (ZIF-8) was found to possess the highest and widest UV reflectance, thereby protecting against sunburn and DNA damage on mouse skin and even achieving a comparable or higher anti-UV efficacy relative to the commercially available UV filters, TiO2 or ZnO, on pig skin, a model that correlates well with human skin. Also, ZIF-8 exerted appealing characteristics for topical skin use with low radical production, low skin penetration, low toxicity, high transparency, and high stability. Conclusion These results confirmed ZIF-8 could potentially be a safe and effective sunscreen surrogate for human, and MOFs could be a novel source to develop more effective and safe UV filters. Graphical Abstract

Keywords

• Sunscreens
• Metal–organic frameworks
• UV
• Diffuse-reflectance
• ZIF-8