Noninternalized MNPs were removed by washing with PBS thrice. Cells were fixed with 4 % of paraformaldehyde for 15 min at room temperature and washed twice with cold PBS. After that, F-actin staining was performed using phalloidin AlexaFluor 488 following manufacturer instructions. For nuclei labelling cell were incubated 10 min at RT with 0,6 µM of DAPI. Finally, the slide was mounted using freshly prepared ProLong reactive. Fluorescence microscopy images were performed using an inverted microscope (Nikon Eclipse Ti-E, Amsterdam, The Netherlands).