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

Abstract

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 O₂, 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.