Size matters: Size Dependency of Gold Nanoparticles Interacting with Model Membranes
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The rapid development of nanomaterials has led to an increase in the number and variety of engineered nanomaterials (ENMs) in the environment. Gold nanoparticles (AuNPs) are an example of a commonly studied ENM whose highly tailorable properties have generated significant interest through a wide range of research fields. In the present work, we report the first qualitative as well as quantitative experimental characterisation of the AuNP-membrane interaction. We investigate the interactions between citrate-stabilised AuNPs (diameters 5, 10, 25, 35, 50, 60 nm) and large unilamellar vesicles (LUVs) acting as a model membrane system. LUVs were prepared in two different formulations using 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine (POPC) and 1,2-dileoyl-sn-glycero-3-phosphocholine (DOPC). Our results show that the interaction between AuNPs and LUVs is size dependent; in particular, we reveal the existence of two AuNP’s critical diameters which determine the fate of AuNPs in contact with a lipid membrane. The results provide a new understanding of the size dependent interaction between AuNPs and lipid bilayers of direct relevance to nanotoxicology and to the design of NP vectors.