Physical and biological optimization of core-shell nanoparticle tracers for in vivo MPI

With improvements in surface coatings, we synthesized MNTs that combine a large core diameter (22-25 nm) for optimal MPI performance with a relatively small hydrodynamic diameter (40-50 nm) required for optimal particokinetics. Hydrodynamic size between 10-100 nm is critical for ensuring long-circulation times [1]. For preliminary safety assessment, we studied the biodistribution and clearance of our optimized MNTs over 7 days using T2-weighted MRI (Figure 2) and tissue histology. Our results show that MNTs accumulate gradually in the liver and spleen, with minimal renal involvement. Furthermore, results indicate that MNTs undergo gradual clearance or breakdown in the liver.