Facile Fabrication of Rare-Earth-Doped Gd2O3 Hollow Spheres with Upconversion Luminescence, Magnetic Resonance, and Drug Delivery Properties
journal contributionposted on 08.12.2011, 00:00 by Gan Tian, Zhanjun Gu, Xiaoxiao Liu, Liangjun Zhou, Wenyan Yin, Liang Yan, Shan Jin, Wenlu Ren, Gengmei Xing, Shoujian Li, Yuliang Zhao
Rare-earth (RE)-doped gadolinium oxide (Gd2O3) hollow nanospheres have been successfully prepared on a large scale via a template-directed method using hydrothermal carbon spheres as sacrificed templates. Scanning electron microscope and transmission electron microscope images reveal that these hollow-structured nanospheres have the mesoporous shells that are composed of a large amount of uniform nanoparticles. By doping the RE ions (Yb/Er) into the Gd2O3 host matrix, these NPs emitted bright multicolored upconversion emissions that can be fine-tuned from green to red by adjusting the codoped Yb/Er ratio under 980 nm NIR laser excitation. The possibility of using these upconversion nanoparticles for optical imaging in vivo has been demonstrated. It was also shown that these Gd2O3 nanospheres brightened the T1-weighted images and enhanced the r1 relaxivity of water protons, which suggested that they could act as T1 contrast agents for magnetic resonance (MR) imaging. Moreover, these hollow spheres can be used as drug delivery host carriers, and drug storage/release properties were investigated using ibuprofen as the model drug. As a result, the so-prepared nanoscaled Gd2O3 hollow spheres bearing upconversion luminescence, MR imaging, and drug delivery capabilities could be potentially employed for simultaneous MR/fluorescent imaging and therapeutic applications.
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upconversion emissionsFacile FabricationScanning electron microscopeUpconversion Luminescencewater protonsdrug delivery capabilitiesMagnetic ResonanceMR imagingmesoporous shellsdrug delivery host carriersGd 2OGd 2O nanosphereshydrothermal carbon spheresmodel drugNPGd 2O host matrixr 1 relaxivityuniform nanoparticles980 nm NIR laser excitationYbtransmission electron microscope imagesT 1 contrast agentsRE ionsupconversion luminescenceupconversion nanoparticles