Metal-organic nanostructure based on TixOy/Ruthenium reaction Units: For CT/MR Imaging-Guided X-ray induced dynamic therapy

Abstract

• A newly multifunctional metal–organic nanostructure—TiZrRuGd-MON was prepared. • The MON showed outstanding X-ray induced dynamic therapy (XDT) effect. • The MON could provide comprehensive and complementary contrast information to guide XDT. We report a computed tomography/magnetic resonance (CT/MR) imaging-guided X-ray induced dynamic therapy (XDT) nanotheranostic platform based on Ti x O y /Ru reaction units. A new metal–organic nanostructure (TiZrRu-MON) was prepared via a solvothermal reaction of [Ti 8 Zr 2 O 12 (COO) 16 ] clusters and bipyridine-(COOH) 2 /Ru(II)-bipyridine-(COOH) 2 co-organic ligands. We demonstrate that the cluster can absorb X-ray and transform the energy to Ru(II)-bipyridine-(COOH) 2 with effective reactive oxygen species (ROS) production, which is five times more than TiZr-MON. In addition, Gd(III) ions were anchored to the bipyridine of MON for concurrent CT/MR imaging. Notably, the TiZrRuGd-MON possesses ultrahigh longitudinal relaxivity ( r 1 value up to 53.09 mM −1 ·s −1 at 1.5 T, 7-fold higher than commercial Gd-DTPA). With the guidance of CT/MR dual-mode imaging that provides comprehensive and complementary contrast information, the TiZrRuGd-MON is monitored to accumulate in tumor sites and eliminate tumor with high efficiency under X-ray irradiation. The TiZrRu-MON-based XDT strategy opens a pathway for clinical translational research of cancer theranostics.