Hybrid mesoporous gadolinium oxide nanorods: a platform for multimodal imaging and enhanced insoluble anticancer drug delivery with low systemic toxicity

We present a facile and scalable method to synthesize PEGylated Eu3+ doped mesoporous gadolinium oxide nanorods for multifunctional biomaterials. By incorporating a facile hydrothermal method, an in situ thermal decomposition process and a surface-modified procedure together, the resultant PEGylated Gd2O3:Eu nanorods reveal rod-like morphology, perfect photoluminescent/magnetic properties, as well as well-defined mesopores. Cell-cytotoxicity assays, hemolyticity against human red blood cells and post-injection histology analysis further demonstrate the excellent biocompatibility of the multifunctional nanorods, indicating the feasibility for their use in disease diagnosis and chemotherapy. The capability of nanorods as contrast agents for MR/X-ray/PL imaging is evaluated in detail through preliminary in vivo characterization. Moreover, to overcome the limitations of insoluble anticancer drugs in clinical applications, we further develop a simple but efficient method to prepare hydrophobic drug (Camptothecin) nanocrystallites in the inner voids of nanorods and testify their enhanced chemotherapy efficiency. Our findings indicate the enhanced chemotherapy efficiency of CPT nanocrystallite-loaded nanorods over traditional CPT-loaded nanoparticles. Due to these advantages, the well-designed PEGylated Gd2O3:Eu nanorods are promising for a simultaneous bioimaging and drug delivery system, which show further potential for clinical applications.