Green synthesized silver nanoparticles induced cytogenotoxic and genotoxic changes in Allium cepa L. varies with nanoparticles doses and duration of exposure.

This study aimed to test the ability of aqueous leaf extract of Eichhornia crassipes (Mart.) Solms-Laubach to synthesize silver nanoparticles (AgNPs) and to estimate the cytotoxicity and genotoxicity of AgNPs using Allium cepa assay. Fresh Eichhornia crassipes plants were collected from the Nile River of Egypt. The mixed-shaped structures of the biogenic AgNPs were qualitatively characterized by UV-vis spectroscopy, scanning electron microscopy and transmission electron microscopy. Selected area electron diffraction confirmed the crystalline structure of AgNPs and energy dispersive X-ray analysis clarified the presence of the elemental silver in a percentage of 83.29%. The biogenic AgNPs were quite stable (0.316) and negatively charged (-18.5 mV) based on the polydispersity index values. Allium cepa L. roots were exposed to several AgNPs concentrations (0, 5, 10, 20, 40 and 80 mg L-1) for different time intervals 2, 4 and 6 h. Cytotoxicity measured by both the spectrophotometric and macroscopic techniques recorded the maximum cell death of root tips of A. cepa after 20 mg L-1 treatment. The analysis of comet assay output images showed an alteration of DNA repair kinetics. The use of aqueous leaf extract of E. crassipes (Mart.) Solms-Laubach in the large-scale production of AgNPs by the method proposed in this study may be a step in improving the water loss in the Nile River. At the same time, a sensitive approach to the cytogenotoxicity of AgNPs must be considered.