Experimental and theoretical prediction of the role nanoparticle agglomeration on modulating cellular dose response

G. Sharma, V. Kodali, M. Gaffrey, W. Wang, K. Minard, N. Karin, J. Teeguarden, B. Thrall
Pacific Northwest National Laboratory, US

Keywords: nanotoxicity, biological modeling, cell dose, iron oxide nanoparticles, oxidative stress, gene expression

Summary:

Nanoparticle (NP) agglomeration in typical culture media is a known confounder of in vitro studies as it affects not only the total delivered dose and kinetics of particle uptake but also the mechanism of uptake. We have developed a novel three-step approach to understand the relationship between applied and delivered particle dose and the physical state of the NP. This approach consists of i) Nanoparticle engineering to create stable agglomerates, ii) Use of theoretical modeling and magnetic particle detection (MPD) technology to quantify the absolute cell associated dose (picogram per cell) of particle agglomerates and, iii) In vitro assays to study the biological effects of agglomerates on mouse lung epithelial cells. Our results indicate that agglomeration state not only changes the amount of dose delivered to cells but also affects their potential to induce cytotoxicity and oxidative stress. In particular, on cellular-dose metric basis small agglomerates induced greater cell response compared to large agglomerates. This difference in response was not apparent when assessed as a function of exposure dose. Our results, therefore, highlight the importance of using absolute cell dose as a metric for assessing biological response for a more meaningful prediction of nanomaterial toxicity in in vitro systems.