Circulation and distribution of gold nanoparticles and induced alterations of tissue morphology at intravenous particle delivery

TLDR

Nanoparticles such as PEG‑coated gold and silica/gold nanoshells are widely used in biomedical imaging and therapy, including photothermal therapy, optical coherence tomography, and resonance‑scattering imaging. The study reports preliminary histological data from light microscopy and TEM to assess tissue changes following intravenous gold nanoparticle administration. Researchers injected 15 nm and 50 nm PEG‑coated gold particles and 160 nm silica/gold nanoshells into rats and rabbits, then measured gold concentrations in organs and blood by atomic absorption spectroscopy and monitored circulation kinetics up to 30 min post‑injection. 15 nm particles dispersed evenly through liver, spleen, and blood, whereas 160 nm nanoshells accumulated predominantly in liver and spleen, with similar biodistribution observed in rabbits after 72 h.

Abstract

Kinetics, biodistribution, and histological studies were performed to evaluate the particle-size effects on the distribution of 15 nm and 50 nm PEG-coated colloidal gold (CG) particles and 160 nm silica/gold nanoshells (NSs) in rats and rabbits. The above nanoparticles (NPs) were used as a model because of their importance for current biomedical applications such as photothermal therapy, optical coherence tomography, and resonance-scattering imaging. The dynamics of NPs circulation in vivo was evaluated after intravenous administration of 15 nm CG NPs to rabbit, and the maximal concentrations of gold were observed 15-30 min after injection. Rats were injected in the tail vein with PEG-coated NPs (about 0.3 mg Au/kg rats). 24 h after injection, the accumulation of gold in different organs and blood was determined by atomic absorption spectroscopy. In accordance with the published reports, we observed 15 nm particles in all organs with rather smooth distribution over liver, spleen and blood. By contrast, the larger NSs were accumulated mainly in the liver and spleen. For rabbits, the biodistribution was similar (72 h after intravenous injection). We report also preliminary data on the light microscopy and TEM histological examination that allows evaluation of the changes in biotissues after gold NPs treatment.