Toxicity of silver nanoparticles in zebrafish models

TLDR

The study aims to clarify the health and environmental effects of silver nanoparticles. Silver nanoparticles were synthesized with starch and bovine serum albumin as capping agents and their effects and distribution were examined in zebrafish embryos by measuring mortality, hatching, pericardial edema, and heart rate. Exposure to silver nanoparticles caused concentration‑dependent mortality, delayed hatching, developmental malformations, and increased apoptosis, with nanoparticles localizing in brain, heart, yolk, and blood, whereas Ag⁺ ions and stabilizers had no effect.

Abstract

This study was initiated to enhance our insight on the health and environmental impact of silver nanoparticles (Ag-np). Using starch and bovine serum albumin (BSA) as capping agents, silver nanoparticles were synthesized to study their deleterious effects and distribution pattern in zebrafish embryos (Danio rerio). Toxicological endpoints like mortality, hatching, pericardial edema and heart rate were recorded. A concentration-dependent increase in mortality and hatching delay was observed in Ag-np treated embryos. Additionally, nanoparticle treatments resulted in concentration-dependent toxicity, typified by phenotypes that had abnormal body axes, twisted notochord, slow blood flow, pericardial edema and cardiac arrhythmia. Ag+ ions and stabilizing agents showed no significant defects in developing embryos. Transmission electron microscopy (TEM) of the embryos demonstrated that nanoparticles were distributed in the brain, heart, yolk and blood of embryos as evident from the electron-dispersive x-ray analysis (EDS). Furthermore, the acridine orange staining showed an increased apoptosis in Ag-np treated embryos. These results suggest that silver nanoparticles induce a dose-dependent toxicity in embryos, which hinders normal development.