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

Area of Science:

• Materials Science
• Nanotechnology
• Photochemistry

Background:

• Commercial sunscreens offer limited protection against UV radiation, necessitating the development of novel UV filters with enhanced safety and efficacy.
• Metal-organic frameworks (MOFs) present a promising platform for UV filter development due to their tunable properties achieved through controlled synthesis.

Purpose of the Study:

• To investigate the optical properties of four zinc-based MOFs.
• To evaluate the potential of these MOFs as effective and safe sunscreen agents.

Main Methods:

• Synthesized four zinc-based MOFs with varying bandgap energies.
• Assessed UV reflectance and anti-UV efficacy on mouse and pig skin models.
• Evaluated ZIF-8's safety and stability for topical application.

Main Results:

• Zeolitic imidazolate framework-8 (ZIF-8) exhibited the highest and broadest UV reflectance among the tested MOFs.
• ZIF-8 demonstrated comparable or superior UV protection to commercial TiO2 and ZnO on pig skin.
• ZIF-8 showed low radical production, minimal skin penetration, low toxicity, high transparency, and excellent stability.

Conclusions:

• ZIF-8 shows significant potential as a safe and effective sunscreen alternative for human application.
• Metal-organic frameworks (MOFs) represent a novel and promising source for developing advanced UV-filtering agents.