Short- and long-term distribution and toxicity of gold nanoparticles in the rat after a single-dose intravenous administration.

Surface chemistry plays an important role in gold nanoparticles (AuNPs) stability and biocompatibility, which are crucial for their implementation into the clinical setting. We evaluated short- (30 min) and long-term (28 days) biodistribution and toxicity of ~20 nm citrate- and pentapeptide CALNN-coated AuNPs after a single intravenous injection in rats. The pattern of AuNPs distribution in Cit- and CALNN-AuNPs-injected rats was very similar in the assessed time-points. Both AuNPs were quickly removed from the bloodstream and preferentially accumulated in the liver. At 28 days liver remained the main accumulation site but at significantly lower levels compared to those found at 30 min. Spleen atrophy and hematological findings compatible with mild anemia were observed in CALNN-AuNPs-administered rats. Under our experimental conditions, surface coating had more impact on toxicity rather than on biodistribution of the AuNPs. Improvements in the design of capping peptides need to be done to increase biomedical applicability of peptide-coated AuNPs. FROM THE CLINICAL EDITOR: The biodistribution and toxicity of ~ 20 nm citrate- and pentapeptide CALNN-coated gold nanoparticles was investigated after a single intravenous injection in rats. Rapid clearance and hepatic accumulation was found at 30-minutes, whereas mild anemia and spleen atrophy was seen 28 days post injection. The authors also concluded that the toxicity was related to the capping proteins as opposed to the biodistribution of the particles, providing important suggestion for future design of gold nanoparticles.