Haemocompatibility evaluation of silica nanomaterials using hemorheological measurements

Silica nanomaterials (NMs) are widely used in semiconductor, agriculture, cosmetics, and biomedical applications, in addition to other industries. We investigated the toxic effect of silica NMs on rheological characteristics of human red blood cells (RBCs), including hemolysis, deformability, aggregation, and morphological changes. Red blood cells were exposed to silica nanoparticles (d=~200 nm) or silica nanowires (d=~200 nm, l=1μm or 10μm) at a range of concentrations and incubation times. Rheological characteristics were measured using microfluidic-laser diffractometry and aggregometry. Overall, at a concentration greater than 12.5μg/ml, the hemolytic activity was shown to be in the order of nanoparticles, short nanowires, and long nanowires. Elongation index (EI) values were insignificant in the RBCs exposed to each of the silica NMs at a concentration of 12.5μg/ml. Aggregation index (AI) values decreased in the short silica nanowires at a concentration of 12.5μg/ml compared to other silica NMs. Therefore, the safe concentration of silica NMs for toxicity, in this study, was considered less than 12.5μg/ml. These hemorheological results provided insight into the interaction between RBCs and silica NMs; they will also help assess the risk of NMs' toxicity in the blood.