Green Synthesis of Iron Oxide Nanoparticles for Use in Pickering Emulsions: In Vitro UV-Absorbing and Antimicrobial Properties

The integration of nanotechnology with green chemistry presents sustainable strategies for developing multifunctional cosmeceutical formulations. In this study, iron oxide nanoparticles (IONPs) were successfully synthesized using antioxidant-rich green tea extract via an eco-friendly method. The nanoparticles were incorporated into a novel Pickering emulsion comprising coconut oil and green tea extract, targeting UV protection and antimicrobial performance. The green-synthesized IONPs displayed strong UV absorption properties, achieving an SPF of 6.20 at 1.0 M concentration, outperforming standard TiO2 nanoparticles (SPF 3.98). The optimized Pickering emulsion formulation showed stability and skin-friendly pH. Antimicrobial studies revealed significant inhibition of Cutibacterium acnes and Staphylococcus aureus, with over 97% microbial reduction observed within 2 h of exposure. This dual-functional system, combining UV protection and antimicrobial effects, demonstrates the potential of green nanomaterials for developing safe, effective, and sustainable skincare formulations. The study provides new insight into the application of iron-based green nanotechnology in surfactant-free emulsions, supporting further innovation in the field of natural photoprotective cosmeceuticals.