Biophysical Society Thematic Meeting

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

, Federica Simonelli

, Davide Bochicchio

1,2

, Riccardo Ferrando

University of Genoa, Genoa, Italy,

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