Biophysical Society Thematic Meeting | Ascona, Switzerland

Liposomes, Exosomes, and Virosomes: From Modeling Complex Membrane Processes to Medical Diagnostics and Drug Delivery

Poster Abstracts

52-POS Board 26 Monolayer-Protected Gold Nanoparticles Walk Into Model Lipid Membranes Step-By- Step Giulia Rossi 1 , Federica Simonelli 1 , Davide Bochicchio 1,2 , Riccardo Ferrando 1 . 1 University of Genoa, Genoa, Italy, 2 SUPSI, Manno, Switzerland. The design of ligand-protected metal nanoparticles (NPs) with biomedical applications relies on the understanding, at the molecular level, of their interactions with cell membranes. Here we study, via unbiased molecular dynamics simulations and free energy calculations, the kinetics and the thermodynamics of the interaction between anionic ligand-protected gold NPs and model lipid membranes. We model the NP-membrane complex at both coarse-grained and atomistic level. We show that the NP−membrane interaction is a three-step process: electrostatics-driven adhesion to the membrane surface, hydrophobic contact and final embedding in the membrane core via anchoring of the charged ligands to both membrane leaflets. Our free energy calculations show that anchoring is highly favorable and not reversible. Furthermore, we show that the interaction pathway of NPs can be influenced by the spatial arrangement of ligands on the NP surface. NPs with homogeneous surface arrangement of anionic and hydrophobic ligands interact with membranes via two metastable configurations: adsorbed at the membrane surface, and membrane-embedded. Patched, heterogeneous ligand arrangements, instead, lead to the stabilization of a third, intermediate metastable configuration, resulting in a much slower kinetics of interaction with the membrane [1]. [1] F. Simonelli, D. Bochicchio, R. Ferrando and G. Rossi, J. Phys. Chem. Lett. 2015, 6, 3175−3179

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