1 Supporting Information A two-step mechanism of cellular uptake of cationic gold nanoparticles modified by (16-mercaptohexa-decyl)trimethylammonium bromide (MTAB) Monika Zarska 1 , Filip Novotny 1,2 , Filip Havel 1,2 , Michal Sramek 1 , Andrea Babelova 3 , Oldrich Benada 4 , Michal Novotny 5 , Hilal Saran 5 , Kamil Kuca 5,6 , Kamil Musilek 5,6 , Zuzana Hvezdova 1+ , Rastislav Dzijak 1 , Marketa Vancurova 1 , Katerina Krejcikova 1 , Blanka Gabajova 1 , Hana Hanzlikova 1 , Lenka Kyjacova 1 , Jiri Bartek 1,7,8 , Jan Proska 1,2* and Zdenek Hodny 1* 1 Department of Genome Integrity, Institute of Molecular Genetics of the CAS, v.v.i., 142 20 Prague 4, Czech Republic 2 Department of Physical Electronics, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, 115 19 Prague 1, Czech Republic 3 Laboratory of Mutagenesis and Carcinogenesis, Cancer Research Institute BMC, Slovak Academy of Sciences, 945 05 Bratislava, Slovakia 4 Laboratory of Molecular Structure Characterization, Institute of Microbiology of the CAS, v.v.i., 142 20 Prague 4, Czech Republic 5 Department of Chemistry, Faculty of Science, University of Hradec Kralove, 500 03 Hradec Kralove, Czech Republic 6 Biomedical Research Center, University Hospital, 500 05 Hradec Kralove, Czech Republic