Facile Synthesis of Single‐Phase Mesoporous Gd 2 O 3 :Eu Nanorods and Their Application for Drug Delivery and Multimodal Imaging

In this work, a new and facile strategy is developed to synthesize a single‐phase Eu 3+ ‐doped mesoporous gadolinium oxide nanorods (MS‐Gd 2 O 3 :Eu@PEG) by incorporating a facile wet‐chemical route, which includes an induced silica layer being coated onto the nanorods, and evolution of pores and formation of channels, as well as a surface‐modified process for multimodal imaging and anti‐cancer drug delivery. The properties of these as‐prepared Gd 2 O 3 :Eu nanorods are characterized by transmission electron microscopy (TEM), X‐ray diffraction (XRD), N 2 adsorption/desorption, and photoluminescence (PL). The in vitro cytotoxicity test, drug loading, and drug release experiments reveal that the MS‐Gd 2 O 3 :Eu@PEG nanorods have good biocompatibility, efficient loading capacity, and pH‐sensitive releasing behavior, suggesting the nanorods could be an ideal candidate as drug delivery vehicles for cancer therapy. Furthermore, the MS‐Gd 2 O 3 :Eu@PEG nanorods show clearly dose‐dependent contrast enhancement in T 1 ‐weighted magnetic resonance images and can potentially be used as a T 1 ‐positive contrast agent. These results indicate our prepared multifunctional mesoporous gadolinium oxide nanorods can serve as a promising platform for simultaneous anti‐cancer drug delivery and multimodal imaging.