Toxicity Patterns of Clinically Relevant Metal Oxide Nanoparticles

Area of Science:

• Materials Science
• Toxicology
• Nanotechnology

Background:

• Nanostructured drugs are increasingly approved, but systematic toxicity studies are lacking.
• Nanoparticle (NP) toxicity data varies significantly based on preparation, size, and shape.
• Understanding the biological impact of clinically relevant NPs is crucial.

Purpose of the Study:

• To systematically investigate the toxicity of various metal oxide nanoparticles (NPs).
• To assess cytotoxicity, acute toxicity in mice, and effects on antibiotic resistance gene transfer.
• To evaluate the safety of TiO2, ZrO2, HfO2, Ta2O5, Fe3O4, and AlOOH NPs.

Main Methods:

• Synthesized NPs (2-10 nm) as aqueous sols using a standardized method.
• Assessed cytotoxicity in cultured human cells at water-solubility-compatible concentrations.
• Determined acute oral toxicity in mice (LD50) and evaluated plasmid transfer between bacteria.

Main Results:

• No NP tested was cytotoxic to human cells at relevant concentrations.
• TiO2, HfO2, Ta2O5, Fe3O4, and AlOOH NPs showed no acute toxicity in mice upon oral administration.
• ZrO2 NPs exhibited significant toxicity (LD50 = 2277.8 mg/kg).
• AlOOH NPs were most hazardous, promoting antibiotic resistance gene transfer.

Conclusions:

• Most investigated metal oxide NPs demonstrate low toxicity in vitro and in vivo.
• ZrO2 NPs present a notable toxicity risk.
• AlOOH NPs pose a significant risk due to their ability to promote antibiotic resistance.
• The biological impact of NPs can be context-dependent, necessitating further investigation.