Probing cell mechanical properties under zinc oxide nanoparticle exposure using atomic force microscopy

Zinc oxide nanoparticles (ZnO NPs) are ubiquitous materials with remarkable physical and chemical properties. The toxicity study of ZnO NPs in biological systems is essential given their broad implementation in various domains. Apart from regular literatures that focused on biological responses through assays, this study focuses on analyzing the mechanical alterations induced by ZnO NPs in the model organism, Saccharomyces cerevisiae . Atomic force microscopy (AFM) was used to determine the changes in the mechanical characteristics namely, young’s modulus and adhesion upon nanoparticle exposure. The recorded force-distance curves were fitted using Sneddon contact mechanics model to obtain young’s modulus data. Results show a decrease in young’s modulus, while an increase in adhesion due to ZnO NP uptake. AFM images display topographical alterations in ZnO exposed cells. Intracellular calcium levels determined using Fura-2 AM probe was elevated at a ZnO NP concentration of 20 µg/ml. Scanning electron microscopy visualized the morphological changes on exposure to ZnO NPs. Hence this study provides critical findings in the mechanical characteristics (young’s modulus and adhesion) of the cell triggered by ZnO NPs uptake using atomic force microscopy. • Zinc oxide NPs trigger changes in cell mechanical properties. • Atomic force microscopy is a suitable technique to evaluate mechanical effects induced by NPs on cells. • Mechanical changes influence various physiological function in cells. • Atomic force microscopy-based nanotoxicology studies are less explored.