Magnetic, long persistent luminescent and mesoporous nanoparticles as trackable transport drug carriers

In this paper, Gd₂O₃@mSiO₂@CaTiO₃:Pr nanoparticles with a novel core/shell structure featured by mesoporous, magnetic and long persistent luminescent properties have been synthesized via a facile template method. The as-prepared nanoparticles show ordered mesoporous characteristics, monodisperse spherical morphology and narrow size distribution, so they are expected to be suitable as a drug carrier. These nanoparticles exhibit bright red phosphorescence at 614 nm after UV irradiation and the persistent luminescence can persist for more than one hour. Moreover, they possess a prominent longitudinal relaxivity (r₁) value of 6.43 mM^-1 s^-1, which suggests that these nanoparticles can be used as MR imaging agents. The combination of long persistent luminescent and magnetic properties reveals the high imaging sensitivity, which suggests that these nanoparticles can be used for imaging in vivo with a high signal to noise ratio. Drug release results indicate that the nanoparticles hold excellent drug sustained properties. The cumulative released amount of drugs can also be easily monitored by the change of luminescence intensity. After modification with polyethylene glycol, the resulting nanoparticles demonstrate good biocompatibility and low toxicity. Furthermore, we can realize in vivo imaging for over 20 min using these nanoparticles. These results indicate the promising use of these nanoparticles as multifunctional traceable drug carriers in vivo.