Comparative toxicity of green and chemically synthesized silver nanoparticles in developing zebrafish: A step toward...

Green silver nanoparticles (G-AgNPs) are emerging nanomaterials for biomedical and environmental applications; however, there are some concerns regarding their potential ecotoxicological risks to aquatic organisms. Therefore, the current study aimed to compare the potential ecotoxicity of G-AgNPs synthesized from the aqueous extracts of Croton urucurana leaves and chemically synthesized AgNPs (PVP-AgNPs) using zebrafish (Danio rerio) as a model system. G-AgNPs and PVP-AgNPs were synthesized and characterized by multiple techniques. Zebrafish embryos and larvae were exposed to G-AgNPs, aqueous leaf extract, PVP-AgNPs, and ionic silver for 144 h. The results showed that G-AgNPs altered survival and early development of zebrafish from 0.5 mg L^-1 (LC_50,144 h = 0.75 mg L^-1), reduced spontaneous contractions and heart rate, indicating their potential embryotoxic, neurotoxic, and cardiotoxic effects to fish. Also, G-AgNPs induced reactive oxygen species (ROS) production and cell death. Isolated extract caused delayed development, decreased spontaneous contractions and heart rate, cell death, and delayed hatching. Overall, G-AgNPs presented higher ecotoxicity in comparison with PVP-AgNPs (LC_50,144 h > 10 mg L^-1), indicating the potential hazardous effects of G-AgNPs to aquatic organisms.