Oxygen Vacancies-Enhanced CeO2:Gd Nanoparticles for Sensing Tumor Vascular Microenvironment by Magnetic Resonance Imaging.

The specific characteristics of the tumor vascular microenvironment such as microvascular permeability and water diffusion have been demonstrated to play essential roles in the evaluation of infiltration of tumors. However, at present, there are few contrast agents (CAs) for magnetic resonance imaging (MRI) to enhance the sensitivity to acquire this vital information. Herein, we develop Gd doped (CeO2:Gd) nanoparticles as CA to detect the tumor vascular microenvironment with high sensitivity. The lattice oxygen vacancies on the surface of CeO2:Gd nanoparticles could bind considerable water molecules to improve the r1 value, achieving an excellent dynamic contrast-enhanced perfusion weighted imaging (DCE-PWI) performance for the measurement of microvascular permeability. The water molecules' diffusion limited by oxygen vacancies of CeO2:Gd nanoparticles further enhance the diffusion-weighted magnetic resonance imaging (DWI) signal in vitro and in vivo. Excitingly, the strategy is not only essential for obtaining tumor vascular microenvironment information but also offers a way for further research of how to design magnetic resonance CAs.