Iron oxide nanoparticulate system as a cornerstone in the effective delivery of Tc-99m radionuclide: a potential molecular imaging probe for tumor diagnosis

Abstract

Background: The evolution of nanoparticles has gained prominence as platforms for developing diagnostic and/or therapeutic radiotracers. This study aims to develop a novel technique for fabricating a tumor diagnostic probe based on iron oxide nanoparticles excluding the utilization of chelating ligands. Methods: Tc-99m radionuclide was loaded into magnetic iron oxide nanoparticles platform (MIONPs) by sonication. 99mTc-encapsulated MIONPs were fully characterized concerning particles size, charge, radiochemical purity, encapsulation efficiency, in-vitro stability and cytotoxicity. These merits were biologically evaluated in normal and solid tumor bearing mice via different delivery approaches. Results: 99mTc-encapsulated MIONPs probe was synthesized with average particle size 24.08 7.9nm, hydrodynamic size 52nm, zeta potential -28mV, radiolabeling yield 96 0.83%, high in-vitro physiological stability, and appropriate cytotoxicity behavior. The in-vivo evaluation in solid tumor bearing mice revealed that the maximum tumor radioactivity accumulation (25.39 0.57, 36.40 0.59 and 72.61 0.82%ID/g) was accomplished at 60, 60 and 30min p.i. for intravenous, intravenous with physical magnet targeting and intratumoral delivery, respectively. The optimum T/NT ratios of 57.70, 65.00 and 87.48 were demonstrated at 60min post I.V., I.V. with physical magnet targeting and I.T. delivery, respectively. These chemical and biological characteristics of our prepared nano-probe demonstrate highly advanced merits over the previously reported chelator mediated radiolabeled nano-formulations which reported maximum tumor uptakes in the scope of 3.65 0.19 to 16.21 2.56%ID/g. Conclusion: Stabilized encapsulation of 99mTc radionuclide into MIONPs elucidates a novel strategy for developing an advanced nano-sized radiopharmaceutical for tumor diagnosis. [Figure not available: see fulltext.]. 2019, Springer Nature Switzerland AG.