In vitro investigation of silica nanoparticle uptake into human endothelial cells under physiological cyclic stretch

Abstract

BackgroundIn general the prediction of the toxicity and therapeutic efficacy of engineered nanoparticles in humans is initially determined using in vitro static cell culture assays. However, such test systems may not be sufficient for testing nanoparticles intended for intravenous application. Once injected, these nanoparticles are caught up in the blood stream in vivo and are therefore in continuous movement. Physical forces such as shear stress and cyclic stretch caused by the pulsatile blood flow are known to change the phenotype of endothelial cells which line the luminal side of the vasculature and thus may be able to affect cell-nanoparticle interactions.MethodsIn this study we investigated the uptake of amorphous silica nanoparticles in primary endothelial cells (HUVEC) cultured under physiological cyclic stretch conditions (1 Hz, 5% stretch) and compared this to cells in a standard static cell culture system. The toxicity of varying concentrations was assessed using cell viability and cytotoxicity studies. Nanoparticles were also characterized for the induction of an inflammatory response. Changes to cell morphology was evaluated in cells by examining actin and PECAM staining patterns and the amounts of nanoparticles taken up under the different culture conditions by evaluation of intracellular fluorescence. The expression profile of 26 stress-related was determined by microarray analysis.ResultsThe results show that cytotoxicity to endothelial cells caused by silica nanoparticles is not significantly altered under stretch compared to static culture conditions. Nevertheless, cells cultured under stretch internalize fewer nanoparticles. The data indicate that the decrease of nanoparticle content in stretched cells was not due to the induction of cell stress, inflammation processes or an enhanced exocytosis but rather a result of decreased endocytosis.ConclusionsIn conclusion, this study shows that while the toxic impact of silica nanoparticles is not altered by stretch this dynamic model demonstrates altered cellular uptake of nanoparticles under physiologically relevant in vitro cell culture models. In particular for the development of nanoparticles for biomedical applications such improved in vitro cell culture models may play a pivotal role in the reduction of animal experiments and development costs.Electronic supplementary materialThe online version of this article (doi:10.1186/s12989-014-0068-y) contains supplementary material, which is available to authorized users.

Gold nanoparticle interactions with endothelial cells cultured under physiological conditions

“…As previously reported, we showed that stretch affects the interaction of endothelial cells with amorphous silica nanoparticles and leads to a reduced internalization. 19 In contrast, studies by Rouse et al…”

“…19 After 24 hours of PEGylated AuNP treatment (25 µg / mL) supernatants were collected for ELISA and cells were fixed and stained as describe above. For quantification, cells were washed twice with PBS and collected in tubes after detachment with trypsin/EDTA (Gibco) solution.…”

“…We have previously shown that silica NPs interact differently with ECs under stretch compared to static culture conditions. 19 The present study aims at determining if a changed nanoparticle-cell interaction is observed by comparing static to flow or stretch culture conditions and whether these conditions result in changes to the induction of cytotoxicity or pro-inflammatory effects in the presence of PEGylated AuNPs or whether the uptake behaviour of the NPs into cells is altered. The third model system is based on an in vitro blood-brain barrier (BBB) co-culture model previously described.…”

Cytotoxicity and DNA damage in mouse macrophages exposed to silica nanoparticles

“…As a non-metal oxide and an important nanomaterial, silica (SiO 2 ) nanoparticles have received much attention. In order to prevent the potential hazards of exposure to SiO 2 nanoparticles, their toxic effects have been summarized from the environmental (Kim et al, 2012), health (Napierska et al, 2010), toxicological (Freese et al, 2014, van der Zande et al, 2014, and scientific respects (Nel et al, 2006). Experiments both in vivo and vitro have been conducted to confirm the underlying toxic actions of SiO 2 nanoparticles.…”

Interaction of Nanoparticles with Blood Components and Associated Pathophysiological Effects

“…Among them are gallium nitride nanoparticles (GaN NPs) [97], cerium dioxide nanoparticles (CeO 2 NPs) [98], gold nanospheres [99,100], silica NPs [101][102][103], CdTe [104], and silver nanoparticles [105] to quote some examples. Silver nanoparticles have received much attention as of late due to the biological effects they produce in endothelial cells, e.g., decreased cell viability, induced apoptosis, increased ROS production, increased production of IL-6 and IL-8 interleukins, and increased expression of adhesion proteins, which can promote inflammation [106][107][108].…”