Particle size-dependent and surface charge-dependent biodistribution of gold nanoparticles after intravenous administration

Twenty-four hours after intravenous injection, the biodistribution of five different sizes (1.4, 5, 18, 80, and 200 nm) and 2.8 nm gold nanoparticles (GNP) with opposite surface charges was quantitatively measured by gamma-spectrometry. The size and surface charge of GNP strongly determine the biodistribution. Most GNP accumulated in the liver increased from 50% of 1.4 nm GNP to >99% of 200 nm GNP. Hepato-biliary clearance of the GNP showed an inverse linear relationship to the GNP diameter over the entire size range of 2.8-200 nm.