Effect of multi-modal environmental stress on dose-dependent cytotoxicity of nanodiamonds in Saccharomyces cerevisiae cells

Abstract

A tremendous increase in the use of functionalised nanomaterials for industrial processes and consumer products inevitably promotes their interaction with living organisms and environment. Previous studies have investigated cell-nanoparticle interactions under conditions otherwise favourable for cell survival and proliferation, yet in real life, organisms are subject to environmental stresses, which may affect their response to nanoparticles. This work investigates the effect of atmospheric-pressure plasma, a model stress inducing environment rich in highly-reactive ROS and RNS species, UV light, and mild heat, on the interactions between inert nanodiamond particles (NDs) and a eukaryotic model organism, Saccharomyces cerevisiae. Plasma treatment significantly affected nanoparticle uptake attributed to changes in membrane properties. Accumulation of nanoparticles in larger deposits inside the cells and around the cell wall affected cell survival and proliferation. Plasma-treated cells exposed to 100 μg ml−1 NDs for 24 h showed significant inhibition of metabolic activity and 55% reduction in cell viability, whereas at lower concentrations (0, 5 and 50 μg ml−1) of NDs, no significant effect on cell viability or cell growth was observed. These results suggest that presence of intra- or extra-cellular stresses is an important determinant of cell fate upon exposure to nanoparticles.