In vitro toxicity of nanoceria: effect of coating and stability in biofluids

TL;DR

This study investigates how different coatings on nanoceria influence its stability and toxicity in biofluids, revealing that coating chemistry significantly impacts cellular interactions and genotoxic effects.

Contribution

It provides new insights into how surface chemistry and stability of nanoceria affect its biological interactions and toxicity in mammalian cells.

Findings

Citrate-coated nanoceria precipitates in biofluids and interacts strongly with cells.

Poly(acrylic acid)-coated nanoceria remains stable and less toxic.

Citrate-coated nanoceria shows toxicity and genotoxicity at concentrations above 1 mM.

Abstract

Due to the increasing use of nanometric cerium oxide in applications, concerns about the toxicity of these particles have been raised and have resulted in a large number of investigations. We report here on the interactions between 7 nm anionically charged cerium oxide particles and living mammalian cells. By a modification of the particle coating including low-molecular weight ligands and polymers, two generic behaviors are compared: particles coated with citrate ions that precipitate in biofluids and particles coated with poly(acrylic acid) that are stable and remain nanometric. We find that nanoceria covered with both coating agents are taken up by mouse fibroblasts and localized into membrane-bound compartments. However, flow cytometry and electron microscopy reveal that as a result of their precipitation, citrate-coated particles interact more strongly with cells. At cerium concentration above 1 mM, only citrate-coated nanoceria (and not particles coated with poly(acrylic acid)) display toxicity and moderate genotoxicity. The results demonstrate that the control of the surface chemistry of the particles and its ability to prevent aggregation can affect the toxicity of nanomaterials.