Interactions between nanoparticles (NPs) and biomembranes depend on the physicochemical properties of the NPs, such as size and surface charge. Here we report on the size-dependent interaction of gold nanoparticles (AuNPs), stabilized with ligands differing in charge, i.e. sodium 3-(diphenylphosphino)benzene sulfonate (TPPMS) and sodium 3,3′,3″-triphenylphosphine sulfonate (TPPTS), respectively, with artificial membranes (black lipid membranes; BLMs) and HeLa cells. The TPPTS-stabilized AuNPs affect BLMs at lower size than TPPMS-stabilized ones. On HeLa cells we found decreasing cytotoxicity with increasing particle size, however, with an overall lower cytotoxicity for TPPTS-stabilized AuNPs. We attribute size-dependent BLM properties as well as reduced cytotoxicity of TPPTS-stabilized AuNPs to weaker shielding of the AuNP core when stabilized with TPPTS. We hypothesize that the partially unshielded hydrophobic gold core can embed into the hydrophobic membrane interior. Thereby we demonstrate that ligand-dependent cytotoxicity of NP can occur even when the NPs are not translocated through the membrane.
Janine Broda, Julia Setzler, Annika Leifert, Julia Steitz, Roland Benz, Ulrich Simon, Wolfgang Wenzel