Gold nanoparticles disrupt zebrafish eye development and pigmentation

Area of Science:

• Nanotoxicology
• Developmental Biology
• Zebrafish Model Systems

Background:

• Gold nanoparticles (AuNPs) have rapidly evolving biomedical applications.
• Systematic toxicological studies are needed to understand AuNP hazard potentials.

Purpose of the Study:

• Investigate the developmental toxicity of 1.3 nm AuNPs functionalized with a cationic ligand (TMAT-AuNPs).
• Assess toxicity in an in vivo embryonic zebrafish model across various exposure concentrations (0.08 to 50 mg/l).

Main Methods:

• Exposure of zebrafish embryos to TMAT-AuNPs.
• Analysis of cell death, gene expression (p53, bax, pax6a, pax6b, otx2, rx1, sox10), and transcription factor localization (whole-mount in situ hybridization).
• Assessment of behavioral changes (swimming activity) and axonal growth.

Main Results:

• TMAT-AuNPs exposure led to smaller, malpigmented eyes with increased cell death.
• Upregulation of p53 and bax gene expression observed.
• Repression of key eye development and pigmentation transcription factors (pax6a, pax6b, otx2, rx1, sox10) in a concentration-dependent manner.
• Reduced spatial localization of pax6a, rx1, sox10, and mitfa.
• Sublethal concentrations caused embryo hypoactivity and axonal growth inhibition.

Conclusions:

• TMAT-AuNPs disrupt zebrafish eye development and pigmentation.
• Observed disruptions correlate with increased cell death and altered gene expression.
• Developmental toxicity extends to behavioral and neuronal damage, indicating significant hazard potential.