Comparative biodistribution of thin-coated iron oxide nanoparticles TCION: Effect of different bisphosphonate coatings

Abstract

Because the nature of their coatings influences the biodistribution of nanocolloids, five different bisphosphonates bearing OH, NH2, NMe2, and N+Me3 groups were evaluated in vivo. 59Fe-labeled iron cores were coated by the different molecules and tested by intravenous injection to healthy adult male Wistar rats. The initial phase was estimated with 59Fe- and 99mTc-labeled nanoparticles biodistribution. The different coatings do not change hydrodynamic radius (∼12 nm) and relaxivities. The negative surface charge is half for particles coated with bisphosphonates bearing quaternary ammonium compared to those bearing a hydroxyl function. Nanoparticle vascular initial half disappearance time range between 25 and 39 min, with hepatic capture between 50 and 80% ID at 18 h. Bones and muscles fix globally around 35% ID at 18 h, with high concentrations in the mineral bones. Hydroxy-bisphosphonates and quaternary ammonium-bisphosphonate-coated nanoparticles are the most efficient for blood remanence, weak liver capture, and bone targeting. © 2002 Wiley-Liss, Inc.