Multimodal imaging can improve the accuracy of cancer diagnosis by combining two or more imaging modalities into one system. In this study, PEGylated BaGdF5 nanoparticles (NPs) were synthesized by a hydrothermal method, and the formed PEG-BaGdF5 NPs showed good X-ray attenuation properties and positive MR contrast effects in vitro. Considering that the overexpression of integrin αvβ3 in the endothelial cells of angiogenic tumor vasculature is universal, RGD peptide, which can recognize and bind integrin αvβ3 specifically, was connected to the surface of PEG-BaGdF5 NPs. The resulting RGD-PEG-BaGdF5 NPs had good biocompatibility and a long half-life in vivo. In VX2 tumor-bearing mice, the HU values and MR signal enhancement of tumor sites in the targeted group were both higher than that in the non-targeted group after intravenous injection of RGD-PEG-BaGdF5 NPs or PEG-BaGdF5 NPs, respectively. Therefore, the RGD-PEG-BaGdF5 NPs may be used as dual-modal CT/MR contrast agents of different types of solid tumors via an active RGD-mediated vasculature targeting pathway.
Hydrogen can be used as an anti-cancer treatment. However, the continuous generation of H 2 molecules within the tumor is challenging. Magnesium (Mg) and its alloys have been extensively used in the clinic as implantable metals. Here we develop, by decorating platinum on the surface of Mg rods, a Mg-based galvanic cell (MgG), which allows the continuous generation of H 2 in an aqueous environment due to galvanic-cell-accelerated water etching of Mg. By implanting MgG rods into a tumor, H 2 molecules can be generated within the tumor, which induces mitochondrial dysfunction and intracellular redox homeostasis destruction. Meanwhile, the Mg(OH) 2 residue can neutralize the acidic tumor microenvironment (TME). Such MgG rods with the micro-galvanic cell structure enable hydrogen therapy to inhibit the growth of tumors, including murine tumor models, patient-derived xenografts (PDX), as well as VX 2 tumors in rabbits. Our research suggests that the galvanic cells for hydrogen therapy based on implantable metals may be a safe and effective cancer treatment.