Karthika Prasad, Nina Recek, Morteza Aramesh, Kateryna Bazaka, Kostya Ostrikov*


 School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Queensland 4000, Australia


Engineered nanomaterials are being increasingly used in a variety of industrial processes and consumer products, resulting in inevitable interactions between these materials and living unicellular and multicellular organisms.1 Over the last years, numerous studies have reported toxicity of different nanoparticles. Thus, there are growing concerns regarding the potential impact of engineered nanoparticles (NPs) on human health and environment. In parallel, the use of plasma for wastewater treatment, decontamination of industrial and medical surfaces, increasing agricultural and fermentation efficiency, and medical treatment of tumors and wound healing is also on the rise. In order to study the synergistic effects of plasma and biocompatible nanodiamond nanoparticles (ND-NPs) on cellular uptake, viability and structure of unicellular organisms, a well-described model organism Saccharomyces cerevisiae was exposed to different concentrations of fluorescent nanodiamond nanoparticles (ND-NPs, 15 nm). Confocal microscopy was used to visualize the nanoparticles inside the cells, demonstrating higher concentration of ND-NPs in intracellular vacuoles and around the cell wall, which affected the morphology and permeability of cell membrane. Cells exposed to ND-NPs (100 µg/ml) in combination with plasma treatment showed significantly lower metabolic activity, increased membrane permeability, and cell cycle arrest, reducing the cell density by 55% compared to control with no ND-NPs. Interestingly, similar plasma treatment in the absence of ND-NPs in suspension did not have a significant effect on cell density. ND-NPs were only cytotoxic at a very high particle concentration of 100 µg/l. ND-NPs (5 µg/ml) and (50 µg/ml) did not cause cytotoxicity or significantly inhibit the cell growth relative to control. These results suggest that while individually both treatments were biocompatible, the synergistic effects that arise from their combination may significantly affect metabolism and survival of target organisms.