Cirsium arvense– Derived ZnO Nanoparticles: Characterization, Mechanistic Modeling, Photocatalytic Degradation of Rhodamine B and Biomedical Applications

ABSTRACT Nanotechnology involves the design, synthesis, and application of nanoscale materials for diverse fields, including environmental remediation, agriculture, medicine, and electronics. Among metal oxide nanomaterials, zinc oxide (ZnO) nanoparticles have attracted considerable attention because of their versatile physicochemical properties and broad functional applications. In this research, ZnO nanoparticles were synthesized using Cirsium arvense leaf extract and characterized by UV‐visible spectroscopy (peak at ∼366 nm), dynamic light scattering (average hydrodynamic diameter ∼19.3 nm), and x‐ray diffraction (hexagonal crystalline structure). The nanoparticles exhibited 96% removal of Rhodamine B dye under UV light, consistent with pseudo‐second‐order kinetics and the Langmuir adsorption model. The ZnO nanoparticles also exhibited concentration‐dependent DPPH radical‐scavenging activity (IC 50 = 39.47 µg/mL), antibacterial activity against Gram‐positive and Gram‐negative bacteria, and greater cytotoxicity toward HeLa cells than toward HEK‐293 cells. Overall, the findings underscore the remarkable promise of green‐synthesized ZnO nanoparticles as sustainable nanomaterials to address environmental challenges and advance biomedical innovations.