The encapsulation of bismuth as BiOCl/Bi2O3 within ultra-short (ca. 50 nm) single-walled carbon nanocapsules (US-tubes) has been achieved. The Bi@US-tubes have been characterized by high-resolution transmission electron microscopy (HR-TEM), energy-dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Bi@US-tubes have been used for intracellular labeling of pig bone marrow-derived mesenchymal stem cells (MSCs) to show high X-ray contrast in computed tomography (CT) cellular imaging for the first time. The relatively high contrast is achieved with low bismuth loading (2.66% by weight) within the US-tubes and without compromising cell viability. X-ray CT imaging of Bi@US-tubes-labeled MSCs showed a nearly two-fold increase in contrast enhancement when compared to unlabeled MSCs in a 100 kV CT clinical scanner. The CT signal enhancement from the Bi@US-tubes is 500 times greater than polymer-coated Bi2S3 nanoparticles and several-fold that of any clinical iodinated contrast agent (CA) at the same concentration. Our findings suggest that the Bi@US-tubes can be used as a potential new class of X-ray CT agent for stem cell labeling and possibly in vivo tracking.
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机译：已经实现了BiOCl / Bi2O3铋在超短（约50 nm）单壁碳纳米囊（US管）中的封装。 Bi @ US管的特征在于高分辨率透射电子显微镜（HR-TEM），能量色散X射线光谱仪（EDS），热重分析（TGA），X射线光电子能谱仪（XPS）和拉曼光谱仪光谱学。 Bi @ US管已被用于猪骨髓源间充质干细胞（MSCs）的细胞内标记，以首次在计算机断层摄影（CT）细胞成像中显示高X射线对比。在US管内以低铋含量（按重量计2.6％）获得了相对较高的对比度，同时又不损害细胞活力。在100 kV CT临床扫描仪中，Bi @ US管标记的MSC的X射线CT成像显示，与未标记的MSC相比，对比度增强几乎增加了两倍。 Bi @ US管的CT信号增强能力是聚合物包覆的Bi2S3纳米颗粒的500倍，是相同浓度下任何临床碘化造影剂（CA）的几倍。我们的发现表明，Bi @ US管可以用作潜在的新型X射线CT试剂，用于干细胞标记和可能的体内跟踪。
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