Nanotoxicity Screening by Impedance Flow Cytometry

Impedance Flow Cytometry: An Effective and Reliable Tool for Nanotoxicity Screening

Nanomaterials (NMs) have gained enormous attention due to their unique properties and have found use everywhere in daily life applications.

However, this widespread use resulted in an increased release of NMs and raised concerns on their adverse impact on the environment and on human health.

Until recently, there was a lack of standardized methods to assess the toxicity potential of these NMs as traditional toxicity assays have been shown to interfere with NMs resulting in false negatives or false positives.

In a recent study, published in the renowned scientific journal ‘Scientific Reports’, the reliability and applicability of label-free impedance flow cytometry for in-vitro nanotoxicity screening were investigated. The study concludes that IFC is a robust and reliable tool that is less prone to interferences due to the advantage of being label-free (1).

"Label-free impedance flow cytometry for nanotoxicity screening"

Abstract:

The development of reliable and cost-efficient methods to assess the toxicity of nanomaterials (NMs) is critical for the proper identification of their impact on human health and for ensuring a safe progress of nanotechnology. In this study, we investigated the reliability and applicability of label-free impedance flow cytometry (IFC) for in vitro nanotoxicity screening, which avoids time-consuming labelling steps and minimizes possible NM-induced interferences. U937 human lymphoma cells were exposed for 24 h to eight different nanomaterials at five concentrations (2, 10, 20, 50, and 100 μg/mL). The NMs’ effect on viability was measured using IFC and the results were compared to those obtained by trypan blue (TB) dye exclusion and conventional flow cytometry (FC). To discriminate viable from necrotic cells, the IFC measurement settings regarding signal trigger level and frequency, as well as the buffer composition, were optimised. A clear discrimination between viable and necrotic cells was obtained at 6 MHz in a sucrose-based measurement buffer. Nanomaterial-induced interferences were not detected for IFC. The IFC and TB assay results were in accordance for all NMs. The IFC was found to be robust, reliable and less prone to interferences due to the advantage of being label-free.

(1) Label-free impedance flow cytometry for nanotoxicity screening. Available from: https://www.nature.com/articles/s41598-019-56705-3 [accessed Feb 27 2020].

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