Time-Resolved Study of Nanoparticle Induced Apoptosis Using Microfabricated Single Cell Arrays.

Peter Röttgermann,Joachim Rädler,Kenneth Dawson

doi:10.3390/microarrays5020008

Peter Röttgermann, Joachim Rädler + Show 1 more

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https://doi.org/10.3390/microarrays5020008

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Abstract

Cell fate decisions like apoptosis are heterogeneously implemented within a cell population and, consequently, the population response is recognized as sum of many individual dynamic events. Here, we report on the use of micro-patterned single-cell arrays for real-time tracking of nanoparticle-induced (NP) cell death in sets of thousands of cells in parallel. Annexin (pSIVA) and propidium iodide (PI), two fluorescent indicators of apoptosis, are simultaneously monitored after exposure to functionalized polystyrene () nanobeads as a model system. We find that the distribution of Annexin onset times shifts to later times and broadens as a function of decreasing NP dose. We discuss the mean time-to-death as a function of dose, and show how the value depends both on dose and time of measurement. In addition, the correlations between the early and late apoptotic markers indicate a systematic shift from apoptotic towards necrotic cell death during the course of the experiment. Thus, our work demonstrates the potential of array-based single cell cytometry for kinetic analysis of signaling cascades in a high-throughput format.

Highlights

The interactions of nanoparticles (NPs) with cells remain poorly understood and this has raised concerns about potential cytotoxicity and environmental risks [1,2]
The majority of studies uses population-based toxicity assays, such as colorimetric assays for cell viability [7,8] and DNA fragmentation assays [9], or techniques with single-cell sensitivity, such as flow cytometry [10,11], image cytometry [12], or fluorescence microscopy [3], but data are taken at limited number of specific time points
Time-lapse microscopy allows for fully time-resolved studies, in which every cell is tracked over time via brightfield and fluorescence microscopy [17,18,19]

Summary

Introduction

The interactions of nanoparticles (NPs) with cells remain poorly understood and this has raised concerns about potential cytotoxicity and environmental risks [1,2]. Many in-vitro and in-vivo studies have probed the safety and biocompatibility of NPs. Evidence for cytotoxicity was found in particular cases of NPs, depending on the cell line and test conditions used [3,4,5,6]. Time-lapse microscopy allows for fully time-resolved studies, in which every cell is tracked over time via brightfield and fluorescence microscopy [17,18,19]. These studies can directly assess the heterogeneous dynamic response of individual cells

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Conclusion