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 mu M 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.
