Biopolymer-stabilized selenium and selenium‑copper nanoparticles with antioxidant and photoprotective dual functionality

The development of multifunctional nanomaterials with antioxidant and photoprotective properties offers significant potential for cosmetic and biomedical applications. In this study, selenium (SeNPs) and selenium–copper (SeCuNPs) nanoparticles were synthesized via chemical reduction using chitosan (CHI) and polyvinyl alcohol (PVA) as stabilizers. Transmission electron microscopy confirmed a spherical morphology, with mean sizes of 85.4 ± 20.2 nm (SeNPs_CHI) and 76.2 ± 12.0 nm (SeCuNPs_CHI), and significantly smaller sizes for PVA-stabilized formulations (34.3 ± 4.0 nm and 32.5 ± 5.8 nm, respectively). X-ray photoelectron spectroscopy (XPS) confirmed the presence of elemental selenium (Se 0 ) and copper (Cu 0 ) in the hybrid nanoparticles. All formulations exhibited potent antioxidant capacity, as demonstrated by ABTS ●+ , DPPH ● , and FRAP assays, outperforming classical standards including Trolox®, ascorbic acid, and quercetin. In vitro sun protection factor (SPF) values were significantly higher than that of the commercial UV filter 2-hydroxy-4-methoxybenzophenone (BZF-3), particularly for SeCuNPs_PVA. Additionally, the nanoparticles displayed excellent photostability under simulated solar irradiation, maintaining or improving SPF over time. These findings highlight the potential of selenium-based nanoparticles, especially hybrid SeCuNPs, as multifunctional agents with strong antioxidant and photoprotective activity, offering a promising platform for the development of next-generation dermocosmetic and biotechnological products. • Selenium and selenium–copper nanoparticles were synthesized via chemical reduction. • Biopolymer stabilizers (chitosan and PVA) influenced nanoparticle size and stability. • SeCuNPs showed superior antioxidant activity vs. Trolox®, quercetin and ascorbic acid. • All NPs demonstrated in vitro SPF values higher than the commercial filter BZF-3. • SeCuNPs exhibited excellent photostability, supporting their multifunctional potential.