Comparison of Metal-Based Nanoparticles and Nanowires: Solubility, Reactivity, Bioavailability and Cellular Toxicity

Area of Science:

• Nanomaterial Science
• Toxicology
• Materials Chemistry

Background:

• Toxicity of metal-based nanoparticles (NP) is increasingly studied.
• Limited knowledge exists on the toxicity of metal-based fibrous nanomaterials, termed nanowires (NWs).

Purpose of the Study:

• To characterize and compare physico-chemical properties of particulate and fibrous nanomaterials (Cu, CuO, Ni, Ag, TiO2, CeO2).
• To assess abiotic metal ion release in physiologically relevant media.
• To compare cytotoxicity and intracellular metal ion release in cell lines.

Main Methods:

• Characterization of nanomaterial properties.
• Abiotic metal ion release assays in artificial alveolar fluid (AAF) and artificial lysosomal fluids (ALF/PSF).
• Cytotoxicity and intracellular metal ion uptake studies using four cell lines.

Main Results:

• Cu, CuO, and Ni materials dissolved in acidic lysosomal fluids but not at neutral pH.
• Cytotoxicity and bioavailability correlated with acellular dissolution rates at pH 4.5.
• Silver (Ag) nanomaterials showed low dissolution but high intracellular bioavailability and cytotoxicity, accumulating in the nucleus.

Conclusions:

• Intracellular bioavailability and toxicity of metal-based nanomaterials are primarily determined by the metal type.
• Nanomaterial shape (NP vs. NW) has a lesser impact on toxicity compared to the metal composition.