Interaction of lipid bilayer with functionalized gold nanoparticles

Abstract

We have investigated the interaction of functionalized anionic Gold nanoparticles (Au NPs) with DMPC (1,2-dimyristoyl-sn-glecerol-3-posphocholine), a phospholipid bilayer. In this study, Citrate-capped Au NPs, 3-mercaptopropanoic acid (MPA) functionalized Au NPs and Glutathione (GSH) functionalized Au NPs have been used. Membrane sensitive probes called PRODAN (6-propionyl- 1,2-dimetylaminonaphthalene) and ANS (8-anilino-1-naphthalenesulphonate) were used to study the interaction between these Au NPs with the lipid bilayer through steady state and time resolved spectroscopy. We observed that the Au NPs bring stability to the bilayer. Also, the extent of interaction of Au NPs with the lipid bilayer was dependent upon the surface ligands used to functionalize those Au NPs. Citrate-capped Au NPs increased the phase transition temperature of the bilayer, upon interaction. We also explored the scope of interaction at different temperatures when the bilayer is present in the different phases; i.e. Liquid crystalline phase and Sol-gel phase. We performed confocal laser scanning microscopy (CLSM) imaging to demonstrate the surface modification in the bilayer due to interaction with Au NPs.