Effect of surface charge and rigidity of liposomes on their interaction with gold nanoparticles

In this study, we advance the understanding of the interactions between liposomes and gold nanoparticles (AuNPs), aiming to provide a scientific foundation for their potential application in nanomedicine, diagnostics, biosensing, and others. We tune the composition of the liposomes, using blends of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) or 2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) lipids with anionic (1,2-dioleoyl-sn-glycero-3-phospho-l-serine, DOPS) or cationic (1,2-dioleoyl-3-trimethylammonium-propane, DOTAP) lipids, to investigate the effect of surface charge and membrane rigidity on their interactions with AuNPs. Via a combination of spectroscopy, microscopy and scattering techniques, we shed light on the state of AuNPs aggregation in these systems as well as the nature and strength of liposome-AuNP and AuNP-AuNP interactions. Notably, through small-angle neutron scattering (SANS) experiments we demonstrate alterations to the lipid membranes induced by AuNPs, leading to liposome shrinkage and the formation of multilamellar liposomes in two of the systems.