Toxicity of silver nanoparticles in zebrafish models

Area of Science:

• Environmental toxicology
• Nanomaterial safety
• Developmental biology

Background:

• Silver nanoparticles (Ag-np) are increasingly used, necessitating an understanding of their environmental and health impacts.
• Zebrafish embryos (Danio rerio) serve as a valuable model for assessing nanoparticle toxicity due to their rapid development and transparency.

Purpose of the Study:

• To investigate the health and environmental effects of silver nanoparticles (Ag-np) synthesized with starch and bovine serum albumin (BSA).
• To determine the distribution patterns and toxicological impacts of Ag-np in zebrafish embryos.

Main Methods:

• Synthesis of Ag-np using starch and BSA as capping agents.
• Exposure of zebrafish embryos to varying concentrations of Ag-np.
• Assessment of toxicological endpoints including mortality, hatching rates, pericardial edema, and heart rate.
• Transmission electron microscopy (TEM) with electron-dispersive X-ray analysis (EDS) for nanoparticle distribution.
• Acridine orange staining to evaluate apoptosis.

Main Results:

• Ag-np exposure led to a concentration-dependent increase in mortality and delayed hatching in zebrafish embryos.
• Observed developmental defects included abnormal body axes, twisted notochord, slow blood flow, pericardial edema, and cardiac arrhythmia.
• TEM-EDS confirmed Ag-np distribution within the brain, heart, yolk, and blood of embryos.
• Acridine orange staining revealed increased apoptosis in Ag-np treated embryos.
• Silver ions (Ag+) and stabilizing agents did not cause significant developmental defects.

Conclusions:

• Silver nanoparticles induce significant, dose-dependent toxicity in zebrafish embryos, impairing normal development.
• The observed adverse effects are attributed to the nanoparticles themselves, not the ions or stabilizing agents.
• This study highlights the potential developmental risks associated with silver nanoparticle exposure.