Preliminary evaluation of a 99mTc labeled hybrid nanoparticle bearing a cobalt ferrite core: in vivo biodistribution.

Magnetic nanoparticles have become important tools for imaging a wide range of diseases, improving drug delivery and applying hyperthermic treatment. Iron oxide based nanoparticles have been widely examined, unlike cobalt ferrite based ones. Herein, monodisperse and stable CoFe2O4 nanoparticles have been produced, coated and further stabilized using ethyl 12-(hydroxyamino)-12-oxododecanoate, poly(lactic-co-glycolic acid) and bovine serum albumin. The final product, NBRh1, was fully characterized and has been directly radiolabeled with 99mTc using SnCl1 as the reducing agent in high yields. In vitro stability and hyperthermic properties of 99mTC-NBRh1 were encouraging for further application in low frequencies hyperthermia and biomagnetic applications. In vivo evaluation followed after injection in healthy mice. The planar and SPECT imaging data as well as the biodistribution results were in accordance, showing high liver and spleen uptake as expected starting almost immediately after administration. In conclusion the preliminary results for nanoparticles bearing a cobalt ferrite core justify further investigations towards potential hyperthermic applications, drug transportation and liver or spleen imaging.