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Yb3+/Er3+-Codoped Bi2O3 Nanospheres: Probe for Upconversion Luminescence Imaging and Binary Contrast Agent for Computed Tomography Imaging

Lei, Pengpeng, Zhang, Peng, Yuan, Qinghai, Wang, Zhuo, Dong, Lile, Song, Shuyan, Xu, Xia, Liu, Xiuling, Feng, Jing, Zhang, Hongjie
ACS Applied Materials & Interfaces 2015 v.7 no.47 pp. 26346-26354
biocompatibility, bismuth, citric acid, computed tomography, emissions, image analysis, ions, irradiation, luminescence, nanospheres, osteoblasts, thermal degradation
In this work, water-soluble Yb³⁺/Er³⁺ codoped Bi₂O₃ upconversion (UC) nanospheres with uniform morphology have been successfully synthesized via a solid-state-chemistry thermal decomposition process. With 980 nm near-infrared irradiation, the Bi₂O₃:Yb³⁺/Er³⁺ nanospheres have bright UC luminescence (UCL). Moreover, multicolor UC emissions (from green to red) can be tuned by simply changing the Yb³⁺ ions doping concentration. After citric acid molecules were grafted on the surface of Bi₂O₃:20% Yb³⁺/2% Er³⁺ nanospheres, the MTT assay on HeLa cells and CCK-8 assay on osteoblasts show that the UC nanospheres exhibit excellent stability and biocompatibility. The possibility of using these nanoprobes with red UCL for optical imaging in vivo has been demonstrated. Furthermore, Bi³⁺ and Yb³⁺ containing nanospheres as binary contrast agent also exhibited significant enhancement of contrast efficacy than iodine-based contrast agent via X-ray computed tomography (CT) imaging at different voltage setting (80–140 kVp), indicating they have potential as CT imaging contrast agent. Thus, Yb³⁺/Er³⁺ codoped Bi₂O₃ nanospheres could be used as dual modality probe for optical and CT imagings.