(292a) Effect of Shear Stress On Cytotoxicity of Silica Nanoparticles

This work investigates how shear stress, a natural physiological occurrence, influences nanoparticle interaction with and cytotoxicity of silica nanoparticles on human endothelial cells. A microfluidic channel allows this investigation under precisely-controlled, physiologically relevant shear stresses, and obtained nanotoxicity results under flow conditions are compared to those obtained under static conditions. The nanoparticles used in this research are 42-nm diameter mesoporous [MS-42] and poly(ethylene glycol) (PEG)-coated mesoporous [MS-42-PEG] silica nanoparticles dosed at 200 µg/ml for 2 hour exposure times. Shear stress control in a microfluidic channel is accomplished mainly by varying channel dimensions, but different flow rates, generating the same shear stress, are also employed to account for variation in nanoparticle number density effects in the toxicity results. The data clearly demonstrate that there is a shear stress dependence on the survival rate of cell populations exposed to nanoparticle flow. Herein, endothelial cells are exposed to the nanoparticle flow under several shear stress values (ranging from 0 to 6.6 N/m²), and toxicity of the MS-42 nanoparticles varies with shear stress while MS-42@PEG, generally known to be less toxic due to the surface modification, shows no significant toxicity to endothelial cells even under the shear stress conditions. This paper demonstrates that flow is an important factor to consider in nanotoxicology and provides a simple and promising platform for this consideration.