Development of radiolabeled dextran coated iron oxide nanoparticles with 111In and its biodistribution studies

Background: The main aim of this study is to radiolabel dextran coated iron oxide nanopartcles (NPs) (with 80 nm hydrodynamic size) with the Indium-111 and evaluaton their biodistributon after intravenous injecton normal mice. Materials and Method: The chelator Diethylenetriamine Pentaacetc Acid (DTPA) dianhydride was conjugated to SPION using a small modificaton of the well-known cyclic anhydride method at a rato of 1:5 (NPs:DTPA) molar rato. The reacton was purified with magnetc assortng columns (MACs) using high gradient magnetc field following incubaton. Then the radiochemical purity of the radiolabeled NPs were determined using RTLC method. The magnetc propertes of nanopartcles were measured by a 1.5 tesla clinical human MRI. Results: The NPs showed high super paramagnetc propertes whereas their r2/r1was 17.6. The RTLC showed that the purity of compound was above 99% after purificaton and the compound has shown a good in-vitro stability untl 6 hours in the presence of human serum. The biodistributon of 111In-DTPA-NPs in mice demonstrated high uptake in the retculoendothelial system (RES) and the blood clearance was so fast. Conclusion: Due to magnificent uptakes of this radiotracer in the liver and spleen, its stability and their fast clearance from other tssues, especially in blood, it is suggested that this radiotracer would be suitable for RES theranostcs purposes.