Green synthesis of copper oxide nanoparticles using ultrasonication-assisted extract of marine brown alga Dictyota dichotoma: Physicochemical characterization and multifunctional biomedical applications

This study investigated a green approach for preparing copper oxide nanoparticles (CuO NPs) using an ultrasonication-assisted aqueous extract of the marine brown alga Dictyota dichotoma . The algal biomass was extracted by ultrasonication, followed by CuO NP formation using copper sulfate under conventional heating and stirring. The resulting material was characterized by ultraviolet-visible (UV-Vis) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), energy-dispersive X-ray spectroscopy (EDX), dynamic light scattering (DLS) and zeta-potential analysis. The preparation exhibited an absorption maximum at 299 nm, while FTIR indicated possible involvement and association of algal-derived functional groups. XRD showed partial correspondence with characteristic CuO reflections, with an apparent crystallite-domain size of 41.29 ± 1.44 nm. TEM revealed irregular, highly aggregated morphology, while EDX detected Cu and O as the principal elements. DLS indicated an apparent hydrodynamic diameter of approximately 87.93 nm and zeta-potential analysis showed condition-dependent negative surface-charge characteristics. Preliminary cytocompatibility assessment in 3T3-L1 cells showed >90% viability. The material exhibited higher apparent antioxidant and enzyme-inhibitory responses than the crude extract. However, NP-specific optical interference was not independently quantified. Overall, the findings support its potential as a multifunctional bioactive nanomaterial requiring further validation.