Changing surface properties of artificial lipid membranes at the interface with biopolymer coated gold nanoparticles under normal and redox conditions.

Gold nanoparticles (NPs) functionalized with biopolymers are increasingly effective in drug-delivery applications. Here, we investigated how chitosan coated NPs and dextran-10 coated NPs regulate their action on DMPC bilayer under normal and stress conditions. We found that chitosan-coated NPs interact with lipid membrane in an intermittent manner, causing lipid loss and partial membrane rupture, while dextran-10 coated NPs mostly induced complete rupture as observed by quartz crystal microbalance. In-situ atomic force microscopy imaging showed that chitosan-treated membranes have a higher surface roughness than those treated with dextran-10. Treatment with 1 μM nitric oxide (NO) radical caused the release of chitosan ligand from the surface of gold NPs (reduced stability) and its aggregation, but the functionality seemed less influenced. Dextran-10 ligand showed no such behavior, while its action was only delayed. Our findings give insights into possible challenges faced by NPs in-situ and show environment dependent effects of NPs on membranes.