Iron oxide nanoparticle toxicity testing using high-throughput analysis and high-content imaging

Applying validated in vitro assays to the study of nanoparticle toxicity is a growing trend in nanomaterial risk assessment. Precise characterisation of reference nanomaterials and a well-regulated in vitro testing system are required to determine the physicochemical descriptors which dictate the toxic potential of nanoparticles. The use of automated, high-throughput technologies to facilitate the identification and prioritisation of nanomaterials which could pose a risk is desirable and developments are underway. In this study, two mammalian fibroblast lines (Balb/c 3T3 and COS-1 cells) were treated with a range of concentrations of iron oxide nanomaterials manufactured for use in medical diagnostics, using an automated platform and high-content-imaging endpoints for cell viability, oxidative stress and DNA damage (double-strand breaks). At the same time, the high-throughput comet assay was employed to measure DNA strand breaks and oxidised bases. Our results show that these methods provide a fast way to determine the toxicity of coated and uncoated iron oxide nanoparticles and, furthermore, to predict the mechanism of toxicity in vitro.