Decrease in Membrane Fluidity and Traction Force Induced by Silica-Coated Magnetic Nanoparticles

Background Nanoparticles are being used increasingly due to their unique physical and chemical properties and small size. It is well-known that nanoparticles cause side effects, however their biophysical assessment remains challenging. We addressed this issue by investigating the effects of silica-coated magnetic nanoparticles containing rhodamine B isothiocyanate [MNPs@SiO2(RITC)] on the biophysical aspects, such as membrane fluidity and traction force of human embryonic kidney 293 (HEK293) cells. We further extended our understanding on the biophysical effects of nanoparticles on cells using a combination of metabolic profiling and transcriptomic network analysis. Results Overdose (1.0 μg/µl) treatment of MNPs@SiO2(RITC) induced lipid peroxidation and decreased membrane fluidity in HEK293 cells. During membrane damage, HEK293 cells were morphologically shrunk and aspect ratio of the cells were significantly decreased upon MNPs@SiO2(RITC) treatment. Each of traction force (measured in micropillar) was found to be increased, thereby increasing the total traction force in MNPs@SiO2(RITC)-treated HEK293 cells. Due to the reduction in membrane fluidity and elevation of traction force, velocity of the cell movement was significantly decreased in MNPs@SiO2(RITC)-treated HEK293 cells. Moreover, intracellular ATP also decreased in a dose dependent manner upon MNPs@SiO2(RITC) treatment. To understand the biophysical changes in cells, we analysed transcriptome and metabolic profiles and generated metabotranscriptomics network. The network showed relationships among peroxidation of lipid, focal adhesion, cell movement, and related genes and metabolites. Furthermore, in silico prediction of the network showed increment in the peroxidation of lipid and suppression of focal adhesion and cell movement.Conclusion Taken together, our results demonstrate that overdosage of MNPs@SiO2(RITC) impairs cellular movement, followed by changes in the biophysical properties of cells, thus highlighting the need for biophysical assessment of nanoparticle-induced side effects.