Luminescent hollow CaWO4 microspheres: template-free synthesis, characterization and application in drug delivery†
Abstract
Luminescent porous micro/nano-structures have gained much attention in recent years due to their potential applications in biomedical fields. Herein, we report the well-dispersed luminescent hollow structural CaWO4 microspheres prepared by a facile hydrothermal method without addition of any templates and additives. The phase, morphology and pore structures of hollow CaWO4 microspheres were well characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and N2 adsorption/desorption. It is observed that the resultant CaWO4 microspheres possess a hollow structure with mesoporous shell and have good biocompatibility, making them suitable to be used as drug carriers. Subsequently, ibuprofen (IBU), a typical anti-inflammatory drug, was successfully loaded into the CaWO4 microspheres and the drug release behavior was investigated. It is found that IBU molecules were successfully introduced into the inner space and mesopores of CaWO4 microspheres and there exist strong interaction between IBU molecules and CaWO4 microspheres. The IBU release from CaWO4 microspheres exhibit a sustained-release property and two-step release mechanism. In addition, the hollow structural CaWO4 microspheres also exhibit bright blue emission after loading of IBU. These results indicate that the luminescent hollow CaWO4 microspheres have promising prospect in the sustained drug release systems and tracking drug release process.