Hollow Bimetallic Complex Nanoparticles For Trimodality Imaging And Photodynamic Therapy In Vivo

Hollow nanoparticles have received an enormous amount of attention in the field of nanomedicine. Herein, water-soluble hollow bimetallic complex nanoparticles, holmium (III)/iridium(III) bimetallic complex nanoparticles (Ir-Ho HNPs), were fabricated via a coordination assembly. Owing to the special metal-to-ligand charge transfer (MLCT) and the heavy-atom effect of Ir(III) in an iridium complex, Jr-Ho HNPs exhibited an intense phosphorescence and the generation of singlet oxygen (O-1(2)). With the long electron relaxation time and high magnetic moment of Ho(III), Ir-Ho HNPs presented a high longitudinal relaxivity (r(2)) value (160.0 mM(-1) s(-1) at 7.0 T). Their unique hollow structure resulted in their strong and stable ultrasound signal in an aqueous solution. As a proof of concept, Ir-Ho HNPs have been developed for the phosphorescence imaging and photodynamic therapy for living cells, ultrasound imaging, and high-field magnetic resonance imaging in vivo. Our work opened up an avenue for novel application of an iridium complex in cancer theranostics.