Biodistribution of colloidal gold nanoparticles after intravenous injection: Effects of PEGylation at the same particle size

Background: Recently, polyethylene glycol (PEG) modified gold nanoparticles have been studied to maintaining long-term stability in biological fluids. Its biodistribution was also reported, however, comparison of bare gold nanoparticles and PEGylated gold nanoparticles with equal particle size is not sufficient. Objective: We prepared bare gold nanoparticles and PEGylated gold nanoparticles with diameters of 20-30-nm or 50-nm to avoid the influence of particle diameter, and studied their biodistribution in the mouse. Methods: Gold concentrations in brain, heart, lungs, liver, stomach, pancreas, spleen, kidneys, blood, urine, and feces were measured at 0.5, 1, 2, 3, 6, 12, 18, 24, and 48 h after administration of gold nanoparticles using inductively coupled plasma atomic emission spectrometry. Results: At 48 h after intravenous administration, accumulation in the liver and spleen was significantly reduced by PEGylation, and the gold amounts of PEGylated gold nanoparticles with diameters of 20-30 nm and 50-nm in the brain were 3.6 times and 2.7 times higher than those of bare gold nanoparticles, respectively. Conclusions: These results indicated that the usefulness of PEGylated gold nanoparticles with small particle size for a drug carrier.