Assessment of silver nanoparticles decorated starch and commercial zinc nanoparticles with respect to their genotoxicity on onion.

High throughput production of silver nanoparticles (AgNPs) having controlled size appropriate for industrial purposes were achieved via using facile and ecofriendly chemical reduction method. Native rice starch was used as reductant for silver ions (Ag+) to silver atoms (Ag0), as well as stabilizing for the obtainable AgNPs. Two different concentrations; 2000 ppm and 4000 ppm were successfully prepared and coded as AgNPs-2000 and AgNPs-4000 respectively. The attained AgNPs were characterized via ultra-visible (UV-vis) spectra, Transmission Electron Microscope (TEM), Energy dispersive X-ray (EDX), Particle size analyzer, polydispersity index (PDI) and zeta potential (ζ-potential). The average particle size of AgNPs (2000 ppm) was 8 nm with PDI = 0.01 which affirm the monodispersity and homogeneity of the produced AgNPs. Meanwhile, the size majority for the as prepared AgNPs (4000 ppm) was 24 nm with PDI = 0.021. Based on the aforementioned data, AgNPs prepared with a high concentration (4000 ppm) compared with the commercialized ZnNPs were used for the genotoxicity study on onion. Root-tips was used for cytogenetic studies using onion (Allium cepa L.) which are excellent materials for cytological and genotoxicity studies. Genotoxicity results explored that, by using AgNPs ≥40 ppm, the abnormalities disturbed chromosomes were observed and detected, that reflects the genotoxicity effect of these nanoparticles at this dose. In addition, the commercial available ZnNPs with the recommended dose (2 g/L) displayed also severe genotoxicity on A. cepa L. root meristem cells.