The effect of shear flow on nanoparticle agglomeration and deposition in in vitro dynamic flow models

Abstract

Traditional in vitro toxicity experiments typically involve exposure of a mono- or co-culture of cells to nanoparticles (NPs) in static conditions with the assumption of 100% deposition (i.e. dose) of well-dispersed particles. However, cellular dose can be affected by agglomeration and the unique transport kinetics of NPs in biological media. We hypothesize that shear flow can address these issues and achieve more predictable dosage. Here, we compare the behavior of gold NPs with diameters of 5, 10 and 30 nm in static and dynamic in vitro models. We also utilize transport modeling to approximate the shear rate experienced by the cells in dynamic conditions to evaluate physiological relevance. The transport kinetics show that NP behavior is governed by both gravity and diffusion forces in static conditions and only diffusion in dynamic conditions. Our results reveal that dynamic systems are capable of producing a more predictable dose compared to static systems, which has strong implications for improving repeatability in nanotoxicity assessments.

• Agglomerate density
• dosimetry
• exposure methods
• nanoparticle transport

Acknowledgements

We thank Prof. Harihara Baskaran at Case Western Reserve University for access to the COMSOL Multiphysics software package.

Declaration of interest

The authors report no conflicts of interest. This work was funded by the Molecular Bioeffects Branch, Bioeffects Division, Human Effectiveness Directorate, 711 Human Performance Wing, Air Force Research Laboratory under the Student Research Participation Program at the U.S. Air Force Research Laboratory administered by the Oak Ridge Institute for Science and Education (to C.M.G. and M.S.).

Supplementary material available online. Supplemental Figures S1-S5.