Silver nanoparticles behaviour in exposed human red blood cells by single cell–inductively coupled plasma–mass spectrometry

Research concerning nanoparticles, NPs, at the single cell level is at the forefront of recent investigations. With the widespread use of silver nanoparticles (AgNPs) in fields like nanomedicine and nanobiotechnology, human exposure has increased. Investigating cellular response to NP exposure in terms of NPs distribution within a cell population is essential. In this sense, single cell (SC)-ICP-MS is a powerful and promising technique that provides quantitative information on a cell-to-cell basis. The present work, in a proof-of-principle experiment, investigates the feasibility of SC-ICP-MS for the determination of surface-adsorbed and intracellular AgNPs in exposed human red blood cells (RBCs). Firstly, RBCs were isolated from whole blood and subsequently incubated with AgNPs suspensions. The exposure was conducted at two dosing concentrations in a low cell:NP ratio of 1:1, and a higher cell:NP ratio of 1:50, for 8, 12, and 24 h. Results showed that the low AgNPs dose concentration had a negligible effect on the uptake by cells, whereas higher doses exhibited a time-dependent uptake. Under specific conditions, the quantification yielded an estimate of 3 AgNPs cell^-1 after 8 h of exposure, 5 AgNPs cell^-1 after 12 h of exposure, and 8 AgNPs cell^-1 after 24 h of exposure. SC-ICP-MS methodology proved to be an excellent tool to track and confirm the presence of AgNPs-containing cells.