Gold nanoparticle-choline complexes can block nicotinic acetylcholine receptors.

We identified a novel class of direct ion-channel blockers of ligand-gated ion-channels called the gold nanoparticle-choline complex. Negatively charged gold-nanoparticles (1.4 nm) block ion pores by binding to the sulfur group of the cysteine loop of nicotinic-acetylcholine receptors (nAChRs), and currents evoked by acetylcholine (Ach) can break these bonds. The current evoked by ACh in nAChRs was blocked directly in ion pores by the gold-nanoparticle-choline complex. In adrenal-gland perfusion studies, the complex also blocked nAChRs by diminishing catecholamine release by about 75%. An in vivo study showed muscle relaxation in rats after injection of the complex. These results will foster the application of gold nanoparticles as a direct ion-channel blocker.