BSA-templated synthesis of Ir/Gd bimetallic oxide nanotheranostics for MR/CT imaging-guided photothermal and photodynamic synergistic therapy.

Precision medicine urges the development of theranostics which can efficiently integrate precise diagnosis and effective therapy. In this study, a facile synthesis of Ir/Gd bimetallic oxide nanotheranostics (termed BSA@Gd 2 O 3 /IrO 2 NPs) with good biocompatibility was demonstrated using a biomineralization method where bovine serum albumin (BSA) served as a versatile template. BSA@Gd 2 O 3 /IrO 2 NPs exhibited high longitudinal relaxivity (5.2 mM -1 s -1 ) and X-ray absorption capability (14.5 Hu mM -1 ), illustrating them to be a good contrast agent for magnetic resonance (MR) and computed tomography (CT) dual-modal imaging. Moreover, BSA@Gd 2 O 3 /IrO 2 NPs can act as not only a photothermal conversion agent with ultrahigh efficiency (66.7%) as well as a good photosensitizer, but also an effective catalase to decompose endogenous H 2 O 2 to produce O 2 , thus relieving hypoxia and enhancing the phototherapeutic effect. Both in vitro and in vivo experiments demonstrated the high effectiveness of BSA@Gd 2 O 3 /IrO 2 NPs in MR/CT dual-modal imaging and photothermal and photodynamic synergistic tumor treatments. This work sheds new light on the development of versatile nanotheranostic systems using mild and robust biomineralization methods.