Toxic effects of silver nanoparticles and nanowires on erythrocyte rheology

Abstract

Rapid developments in the food applications of silver nanomaterials (Ag-NMs) have resulted in concerns related to the risk of overexposure of human blood. We investigated the effect of size and aspect ratio of Ag-NMs on theological characteristics of human erythrocytes, including hemolysis, deformability, aggregation, and morphological changes. Red blood cells (RBCs) were exposed to two different sizes of spherical particles (d similar to 30 nm or 100 nm) or nanowires (d similar to 40 nm, 1-21 mu m in length) at a range of concentrations and incubation times. The concentrations of Ag-NMs were carefully chosen to avoid any hemorheological alteration due to hemolysis. Rheological properties were measured using microfluidic-laser diffractometry and aggregometry. RBC deformability apparently decreased after treatment with a low concentration of Ag-NPs for a short exposure time. However, RBC aggregation was significantly altered after treatment with a low concentration of either Ag-NWs or large Ag-NPs compared to small Ag-NPs. Additional experiments with Ag ions confirmed that the observed rheological changes were mainly caused by the Ag-NMs rather than the Ag ions. These hemorheological findings provide a better understanding of the interaction between RBCs and Ag-NMs and will help in assessing the risk of nanomaterial toxicity in blood. (C) 2014 Elsevier Ltd. All rights reserved.