Ivan M. Kempson et al. have investigated the intravenous delivery and excretion of polyethylene glycol (PEG)-coated gold nanoparticles (GNPs) in the whiskers and at the pilosebaceous unit in a mouse model. The use of X-ray fluorescence allowed visualisation of this deposition and, after 14 days, gold bands could be visualised in the hairs, the pharmacokinetic profiles of which indicated the blood concentration kinetics.
This deposition of nanoparticles was found to take place intermittently during this 14 day period, so demonstrating the prolonged mobility of these nanoparticles within the body. Furthermore, confocal microscopy was used to make a 3D reconstruction of nanoparticle distribution leading to identification of nanoparticle aggregates within the medullary canal.
These results are of interest in understanding the fate and excretion of nanoparticles from the body. Also, due to the successful elucidation of kinetic information from hair samples, this illustrates the potential for testing the nanoparticle load in the body via hair sampling as oppose to blood sampling.