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

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 nanopartides. 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 nanopartide uptake attributed to changes in membrane properties. Accumulation of nano-partides in larger deposits inside the cells and around the cell wall affected cell survival and proliferation. Plasma-treated cells exposed to 100 mu g 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 mu g ml(-1)) of NDs, no significant effect on cell viability or cell growth was observed. These results suggest that presence of infra- or extra-cellular stresses is an important determinant of cell fate upon exposure to nanoparticles. (C) 2019 Elsevier B.V. All rights reserved.