Bismuth labeling for the CT assessment of local administration of magnetic nanoparticles

Many therapeutic applications of magnetic nanoparticles involve the local administration of nanometric iron oxide based materials as seeds for magnetothermia or drug carriers. A simple and widespread way of controlling the process using x-ray computed tomography (CT) scanners is desirable. The combination of iron and bismuth in one entity will increase the atenuation of x-rays, offering such a possibility. In order to check this possibility core?shell nanocrystals of iron oxide@bismuth oxide have been synthesized by an aqueous route and stabilized in water by polyethylene glycol (PEG), and we have evaluated their ability to generate contrast by CT and magnetic resonance imaging (MRI) to measure the radiopacity and proton relaxivities using phantoms. High-resolution scanning transmission electron microscopy (STEM) revealed that the material consists of a highly crystalline 8 nm core of maghemite and a 1 nm shell of bismuth atoms either isolated or clustered on the nanocrystal?s su...

S Veintemillas-Verdaguer, Y Luengo, C J Serna, M Andr?s-Verg?s, M Varela, Macarena Calero, Ana Lazaro-Carrillo, Angeles Villanueva, A Sisniega, P Montesinos and M P Morales

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