Organ-specific distribution of gold nanoparticles by their surface functionalization.

The behavior and fate of intravenously (i.v.) injected nanoparticles (NPs) can be controlled by several physicochemical factors including size, shape and surface charge. To evaluate the role of surface charge on distribution of NPs, we used neutral-charged 15-nm-sized polyethylene glycol-coated gold nanoparticles (AuNPPEG) as a core NP and carboxyl or amine groups were conjugated to AuNPPEG to generate negative (AuNPCOOH) or positive AuNP (AuNPNH2), respectively. Each type of AuNP was i.v. injected into mice (1mgkg(-1)) and the concentration of Au was measured in different organs at 30min, 4, 24h, 7, 14days, 1, 3 and 6months post-injection. The organ distribution also showed the higher deposition rate depending on their functional groups: AuNPPEG for mesenteric lymph node, kidney, brain and testis; AuNPCOOH for liver; AuNPNH2 for spleen, lung and heart. The blood circulation time and the major excretion route were different depending on their functional groups. In conclusion, functional groups conjugated on the surface of AuNPs produce differences in blood kinetics, organ distribution and elimination pattern which can be important information for directing NPs to specific organs or improving the kinetic properties. Copyright (c) 2014 John Wiley & Sons, Ltd.