Dopamine Functionalized Polyethylene Glycol for Improving Stability of Gold Nanoparticles against Reactive Oxygen Species in Serum.

PEGylation is the most effective antifouling method for the surface modification of gold nanoparticles (AuNPs). However, thiol-terminated polyethylene glycol (PEG) ligands tethered on the AuNPs are instable in serum and can detach from the AuNP surface, resulting in a significant reduce of their antifouling properties. Herein, it is reported that reactive oxygen species (ROS) is a major factor causing the detachment of PEG ligands from AuNP surfaces. By covalently backfilling dopamine-functionalized PEG on the AuNPs, the stability of PEG ligands on AuNP surface and the antifouling ability of AuNPs can be effectively improved. Tuning the balance between ROS and dopamine-functionalized PEG can be used as a new strategy to control the self-assembly of AuNPs and serum proteins.