Cells were derived from cervical cancer (HeLa cell line). They were cultured in Iscove´s Modified Dulbecco´s Medium (IMDM) with 10 % fetal calf serum (FCS) and 1 % Penicillin-Streptomycin (P/S). Cells were seeded one day prior to microscopy at 20 000 cells per 96 well glass bottom chamber with 200 µl IMDM Medium with 10 % FCS and 1 % P/S in each well. For this purpose, the cells were detached from the cell culture dish with Trypsin/EDTA, counted and then seeded accordingly. The next day the functionalized SWCNTs were directly added to the wells into the medium resulting in a final concentration of 1 nM. After 1 h incubation the cells were washed three times with IMDM with 10 % FCS and 1 % P/S and imaged in the same medium.