Facile one-pot synthesis of hollow mesoporous fluorescent Gd2O3:Eu/calcium phosphate nanospheres for simultaneous dual-modal imaging and pH-responsive drug delivery

摘要

The hollow nanospheres (NSs) composed of lanthanides have become a hot topic owing to their uncommon magnetic and optical properties arising from the 4f electrons. However, only a few novel methods have been developed for effectively integrating small calcium phosphate (CaP) nanoparticles and rare earth oxide drug carriers into an individual hollow mesoporous nanosphere. Herein, we report a facile, reproducible, room-temperature solution method to prepare multifunctional fluorescent hollow mesoporous Gd2O3:Eu/CaP (designated as HM-Gd2O3:Eu/CaP) NSs by using polyacrylic acid calcium (PAA-Ca) as a template. The excellent luminescent property and obvious T1-enhancement effect as well as the HM structure endow the HM-Gd2O3:Eu/CaP NSs with the capacity of simultaneous dual-modal fluorescence, magnetic resonance (MR) imaging and drug delivery. The nanocontainer-functionality of the HM-Gd2O3:Eu/CaP NSs is further validated upon filling with the anti-cancerogenic agent doxorubicin (drug-loading capacity is 749 mu g mg(-1)). In addition, the HM-Gd2O3:Eu/CaP NSs display excellent pH responsive and sustained drug release property. In vitro cell cytotoxicity tests verify the HMGd2O3:Eu/CaP NSs have good biocompatibility when the concentration <25 mg mL(-1). Taken together, the results suggested that the HM-Gd2O3:Eu/CaP NSs can be applied as fluorescence and MR dual-modal imaging contrast agents and drug delivery vehicles. (C) 2017 Elsevier Ltd. All rights reserved.