Green Synthesis and Characterization of Silver Nanoparticles (AgNPs) Using Leaf Extract of Solanum nigrum and Assessment of Toxicity in Vertebrate and Invertebrate Aquatic Animals

Abstract

In this study, silver nanoparticle was green synthesized using the leaf extract of Solanum nigrum (Sn-AgNPs) and bio-physically characterized by UV–Vis spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), High resolution transmission electron microscopy (HR-TEM), Zeta potential analysis and Energy dispersive X-ray (EDX) analysis. The ecotoxicity of silver nanoparticle (Sn-AgNPs) were tested against both invertebrate (Ceriodaphnia cornuta and Paramecium sp.) and vertebrate aquatic animal models (Guppy fish, Poecilia reticulata) in comparison with bare silver nitrate. Sn-AgNPs were observed to be less toxic than ionic silver (silver nitrate). The ecotoxicity levels of Sn-AgNPs were found to be varied between tested organisms. Sn-AgNPs caused 100% mortality of freshwater crustacean, C. cornuta at 50 µg mL−1. At concentration below 50 µg mL−1 (10–30 µg mL−1), abnormality in the swimming behavior of C. cornuta was noticed. The ingestion and accumulation of Sn-AgNPs in the intestine of C. cornuta neonates were visualized under light and confocal laser scanning microscopic images. The ecotoxicity of Sn-AgNPs to the freshwater protozoan ciliate, Paramecium sp. showed that 30 µg mL−1 were lethal and produced 100% mortality at the same concentration. The study concludes that Sn-AgNPs was less toxic to both invertebrate and vertebrate models compared to ionic silver nitrate.