Lanthanide nanoparticles as vascular contrast agents for micro - CT

Introduction Vascular development is extensively studied in small animals. Micro-CT is routinely used to study the vasculature and it requires a high-attenuating contrast agent to remain in the blood pool during in vivo imaging (i.e. tens of minutes). This can be achieved by using polymer-encapsulated nanoparticles exceeding 10 nm in diameter. Although nanoparticle agents exist for micro-CT, they are predominantly based on iodine, which has a low atomic number. Superior CT contrast can be achieved using lanthanides (e.g. Er). While lanthanide-based contrast agents are used clinically in MRI, they are composed of small molecules (<1 nm) that exit the blood pool of small animals within seconds. Thus, the purpose of this work is to develop and characterize an in vivo vascular contrast agent composed of polymer-encapsulated erbium nanoparticles (ErNP) exceeding 10 nm in size.