Bio‐Engineered Silver Nanoparticles, Characterization, and Time‐Dependent Toxicity against Common Carp (<i>Cyprinus carpio</i>)

Bio-engineered silver nanoparticles (BE-AgNPs) are receiving discernible attention due to their diverse application history; however, the interaction of silver nanoparticles (Ag-NPs) with the environment and their toxicity in aquatic organisms is a matter of concern debate. Therefore, the current study aims to evaluate the bio-fabrication of Ag-NPs using Bellis perennis (B. perennis) plant flower extract and to assess their toxicity against Cyprinus carpio as an aquatic model organism. For this purpose, BE-AgNPs were synthesized and characterized using advanced analytical techniques (SEM, TEM, FTIR, and UV-visible absorption spectra), which showed that well-dispersed and cubical Ag-NPs with an average size of 15.4 nm were obtained. In addition, C. carpio after 96-h LC₅₀ test period were exposed to three determined concentrations, including 5, 10, and 15 mg/L of BE-AgNPs for 1, 2, 3, 4, 7, 14, and 21 days, respectively, for tissue histopathology and genotoxicity. Histopathological results revealed that BE-AgNPs caused degeneration, necrosis, inflammation, and fibrosis in the muscles, liver, intestine, and gills of exposed C. carpio tissues using H and E staining slides. Moreover, BE-AgNPs caused DNA damage to C. carpio erythrocytes using the comet assay (single-cell gel electrophoresis) technique. The study confirmed that BE-AgNPs induce significant myotoxicity, hepatotoxicity, branchial toxicity, intestinal toxicity, and genotoxicity in C. carpio. These findings highlight the environmental and ecological risks associated with the use of bio-engineered silver nanoparticles, particularly in aquatic ecosystems.