Gadolinium-Engineered Magnetic Alloy Nanoparticles for Magnetic Resonance T1/T2 Dual-Modal and Computed Tomography Imaging

Through the facile one-pot reaction, we herein report, for the first time, the syntheses and characterization of FeGdPt nanoparticles (FeGdPt NPs) as well as their optimal parameters to yield single, pure alloy nanoparticles for magnetic resonance (MR) T1/T2 dual-modal and X-ray computed tomography (CT) imaging. The corresponding EDS mapping and PXRD reveal that the Gd and Fe elements are distributed randomly as a solid solution in a face-centered cubic structure of the Pt element. FeGdPt NPs give r1 (longitudinal relaxivity) and r2 (transverse relaxivity) values of 2.37 and 15.25 s-1 mM-1 at 0.47 T, respectively. The r1 value of FeGdPt NPs, which originates from the alloying Gd component in the Pt-based crystal structures, is sufficiently high to provide a significant MR T1 contrast. Also, the r2/r1 ratio (6.44) of FeGdPt NPs is within an optimal range of 3-10 and is suitable for the T1-/T2-weighted imaging. Experimentally, FeGdPt NPs exhibit prominent positive (T1) and negative (T2) contrasts in both in vitro and in vivo studies, demonstrating their practicability for T1/T2 dual-modal imaging. Further in vitro and in vivo tests show the potential of FeGdPt NPs in the CT contrast. The combination of MR T1/T2 dual-modal and CT imaging makes feasible the application of FeGdPt NPs as multifunctional contrast agents.