Effect of silica-coated magnetic nanoparticles on rigidity sensing of human embryonic kidney cells

Abdurazak Aman Ketebo,Tae Hwan Shin,Gwang Lee,Sungsu Park,Myeongjun Jun

doi:10.1186/s12951-020-00730-2

Abdurazak Aman Ketebo, Tae Hwan Shin + Show 3 more

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https://doi.org/10.1186/s12951-020-00730-2

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Abstract

BackgroundNanoparticles (NPs) can enter cells and cause cellular dysfunction. For example, reactive oxygen species generated by NPs can damage the cytoskeleton and impair cellular adhesion properties. Previously, we reported that cell spreading and protrusion structures such as lamellipodia and filopodia was reduced when cells are treated with silica-coated magnetic nanoparticles incorporating rhodamine B isothiocyanate (MNPs@SiO2(RITC)), even at 0.1 μg/μL. These protruded structures are involved in a cell’s rigidity sensing, but how these NPs affect rigidity sensing is unknown.ResultsHere, we report that the rigidity sensing of human embryonic kidney (HEK293) cells was impaired even at 0.1 μg/μL of MNPs@SiO2(RITC). At this concentration, cells were unable to discern the stiffness difference between soft (5 kPa) and rigid (2 MPa) flat surfaces. The impairment of rigidity sensing was further supported by observing the disappearance of locally contracted elastomeric submicron pillars (900 nm in diameter, 2 μm in height, 24.21 nN/μm in stiffness k) under MNPs@SiO2(RITC) treated cells. A decrease in the phosphorylation of paxillin, which is involved in focal adhesion dynamics, may cause cells to be insensitive to stiffness differences when they are treated with MNPs@SiO2(RITC).ConclusionsOur results suggest that NPs may impair the rigidity sensing of cells even at low concentrations, thereby affecting cell adhesion and spreading.

Highlights

Nanoparticles (NPs) can enter cells and cause cellular dysfunction
We reported that Magnetic nanoparticles (MNPs)@ SiO2(RITC) induce the production reactive oxygen species (ROS), that leads to ER stress, decreased proteasome activity, and altered cellular metabolism [4, 9, 24], suggesting that careful studies are required before the applications of MNPs@SiO2(RITC) in vivo
We describe the effect of MNPs@ SiO2(RITC) on the mechanobiological aspects of human embryonic kidney cells (HEK293) using soft (5 kPa) and rigid (2 MPa) flat PDMS surfaces as well as elastomeric submicron pillars (900 nm in diameter, 2 μm in height, 24.21 nN/μm in stiffness k) (Fig. 1)

Summary

Introduction

Nanoparticles (NPs) can enter cells and cause cellular dysfunction. For example, reactive oxygen species generated by NPs can damage the cytoskeleton and impair cellular adhesion properties. We reported that cell spreading and protrusion structures such as lamellipodia and filopodia was reduced when cells are treated with silica-coated magnetic nanoparticles incorporating rhodamine B isothiocyanate (MNPs@SiO2(RITC)), even at 0.1 μg/μL. These protruded structures are involved in a cell’s rigidity sensing, but how these NPs affect rigidity sensing is unknown. To reduce the adverse effect of MNPs, they are coated with biocompatible components such as polyethylenimine, polysaccharide, and silica [15,16,17,18] Among these MNPs, silica-coated magnetic nanoparticles incorporating rhodamine B isothiocyanate (MNPs@ SiO2(RITC)) composed of silica shells and MNP cores in the range from 1 to 10 μg/μl are used for cell labeling [18], hyperthermia [19] and magnetic resonance imaging (MRI) [20]. We reported that MNPs@ SiO2(RITC) induce the production ROS, that leads to ER stress, decreased proteasome activity, and altered cellular metabolism [4, 9, 24], suggesting that careful studies are required before the applications of MNPs@SiO2(RITC) in vivo

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