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@Gd2O3/IrO2 NPs) with good biocompatibility was demonstrated using a biomineralization method where bovine serum albumin (BSA) served as a versatile template. BSA@Gd2O3/IrO2 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@Gd2O3/IrO2 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 H2O2 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@Gd2O3/IrO2 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.

Automated summary

This study demonstrated a facile synthesis of Ir/Gd bimetallic oxide nanotheranostics (BSA@Gd2O3/IrO2 NPs) with good biocompatibility using a biomineralization method. BSA@Gd2O3/IrO2 NPs showed high longitudinal relaxivity and X-ray absorption capability, making them suitable for MR and CT dual-modal imaging. Additionally, BSA@Gd2O3/IrO2 NPs acted as efficient photothermal conversion agents and photosensitizers, and could decompose endogenous H2O2 to produce O-2, improving the phototherapeutic effect. This work is important for the development of versatile nanotheranostic systems using mild and robust biomineralization methods.