Green Synthesis and Comparative Analysis of Silver, Copper Oxide, and Bimetallic Ag/CuO Nanoparticles Using Cistus creticus L. Extract: Physicochemical Properties, Stability, and Antioxidant Potential

This study investigates silver (Ag), copper oxide (CuO), and bimetallic Ag/CuO nanoparticles (NPs) synthesized using <i>Cistus creticus</i> L. extract, focusing on their synthesis, physicochemical characteristics, and antioxidant activity. Green synthesis methods utilizing plant extracts offer environmentally benign routes for nanoparticle fabrication, attracting significant interest across multiple fields. NP formation was confirmed by UV/Vis and total X-ray fluorescence (TXRF) spectroscopy, while dynamic and electrophoretic light scattering (DLS, ELS) characterized particle size and ζ-potential, respectively. AgNPs exhibited the smallest particle size (30.8 ± 8.81 nm), while CuONPs had the largest (44.07 ± 19.19 nm). For Ag/CuONPs, the ζ-potential value was -77.9 ± 2.99 mV. Morphological and structural analyses performed using transmission electron microscopy (TEM), selected area electron diffraction (SAED), and X-ray diffraction (XRD) revealed that AgNPs were spherical, while CuONPs and Ag/CuONPs exhibited spherical and polymorphic structures. Colloidal stability studies over 60 days demonstrated that the NPs were highly stable, indicating their suitability for pharmaceutical and cosmetic applications. Antioxidant activity, assessed via the DPPH assay, demonstrated that CuONPs had the highest free radical scavenging activity. By systemically comparing Ag, CuO, and bimetallic Ag/CuONPs synthesized from <i>Cistus creticus</i> L. extract, this study provides valuable insights for the development of tailored nanomaterials with diverse applications in pharmaceutics and cosmetics.