Colonizing microbiota protect zebrafish larvae against silver nanoparticle toxicity.

Area of Science:

• Environmental Toxicology
• Microbiology
• Nanotechnology

Background:

• Metal-based nanoparticles (nAg, nZnO) pose risks to health due to antimicrobial activity.
• Disruption of host-microbiota interactions may contribute to nanoparticle toxicity.
• Understanding these indirect effects is crucial for accurate risk assessment.

Purpose of the Study:

• To compare the acute toxicity of silver nanoparticles (nAg) and zinc oxide nanoparticles (nZnO) in germ-free versus microbially colonized zebrafish larvae.
• To investigate the role of host-microbiota interactions in mediating nanoparticle toxicity.
• To assess particle-specific effects and potential bactericidal mechanisms.

Main Methods:

• Acute toxicity testing of nAg and nZnO on germ-free and conventionally colonized zebrafish larvae over 48 hours.
• Comparison of mortality rates between germ-free and colonized larvae.
• Response addition modeling to evaluate particle-specific effects and microbial viability assessment.

Main Results:

• Germ-free zebrafish larvae were more sensitive to nAg than colonized larvae; silver ion toxicity was similar.
• Colonizing microbiota conferred a particle-specific protection against nAg toxicity.
• nZnO toxicity did not differ between germ-free and colonized larvae, and showed no significant bactericidal effects.

Conclusions:

• Host-microbiota interactions are critical for assessing nanoparticle toxicity, particularly for nAg.
• The protective effect of microbiota against nAg is linked to their potential bactericidal impact on beneficial microbes.
• This study provides a framework for evaluating microbiota interference in nanomaterial toxicity.