Active targeted dual-modal CT/MR imaging of VX2 tumors using PEGylated BaGdF5 nanoparticles conjugated with RGD

Abstract

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 α_vβ₃ in the endothelial cells of angiogenic tumor vasculature is universal, RGD peptide, which can recognize and bind integrin α_vβ₃ 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.