Emerging metrology for high-throughput nanomaterial genotoxicology

Abstract

The rapid development of the engineered nanomaterial (ENM) manufacturing industry has accelerated the incorporation of ENMs into a wide variety of consumer products across the globe. Unintentionally or not, some of these ENMs may be introduced into the environment or come into contact with humans or other organisms resulting in unexpected biological effects. It is thus prudent to have rapid and robust analytical metrology in place that can be used to critically assess and/or predict the cytotoxicity, as well as the potential genotoxicity of these ENMs. Many of the traditional genotoxicity test methods [e.g. unscheduled DNA synthesis assay, bacterial reverse mutation (Ames) test, etc.,] for determining the DNA damaging potential of chemical and biological compounds are not suitable for the evaluation of ENMs, due to a variety of methodological issues ranging from potential assay interferences to problems centered on low sample throughput. Recently, a number of sensitive, high-throughput genotoxicity assays/platforms (CometChip assay, flow cytometry/micronucleus assay, flow cytometry/γ-H2AX assay, automated ‘Fluorimetric Detection of Alkaline DNA Unwinding’ (FADU) assay, ToxTracker reporter assay) have been developed, based on substantial modifications and enhancements of traditional genotoxicity assays. These new assays have been used for the rapid measurement of DNA damage (strand breaks), chromosomal damage (micronuclei) and for detecting upregulated DNA damage signalling pathways resulting from ENM exposures. In this critical review, we describe and discuss the fundamental measurement principles and measurement endpoints of these new assays, as well as the modes of operation, analytical metrics and potential interferences, as applicable to ENM exposures. An unbiased discussion of the major technical advantages and limitations of each assay for evaluating and predicting the genotoxic potential of ENMs is also provided.

Micronuclei Detection by Flow Cytometry as a High-Throughput Approach for the Genotoxicity Testing of Nanomaterials

“…We are then facing a complex scenario where a huge amount of NMs needs to be tested under multiple modulatory variables. For this reason, high-throughput methods are required to generate rapid and robust data that can be used to assess and/or predict the potentially harmful effects of NMs in biological systems, as postulated by different authors [6][7][8]. Previous to the use of any analytical method, dispersion procedures are indispensable to get NMs uniform samples.…”

Genotoxic and mutagenic properties of Ni and NiO nanoparticles investigated by comet assay, γ‐H2AX staining, Hprt mutation assay and ToxTracker reporter cell lines

“…The remaining two cell lines indicate general p53‐dependent cellular stress ( Btg2 reporter) or protein unfolding ( Ddit3 reporter). The use of these reporter assays provides a more high‐throughput alternative compared with many other assays [Nelson et al, ]. We have previously elucidated the applicability of three of these reporters for NPs [Karlsson et al, ].…”

ToxTracker Reporter Cell Lines as a Tool for Mechanism-Based (Geno)Toxicity Screening of Nanoparticles—Metals, Oxides and Quantum Dots

“…However, these methods are relatively time-consuming and there is consequently a great demand for efficient and more high throughput assays for screening of the genotoxicity of NPs [4]. As reviewed by Nelson et al [5], some of the established genotoxicity assays have been modified and optimized to give increased sample capacity and throughput such as flow cytometry based micronucleus assay as well as comet on a chip.…”