Yuan Ye, Zhang Zhe, Hou Weiying, Qin Weiping, Meng Zihui, Wu Changfeng
State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, China-Japan Union Hospital, Jilin University, Changchun, Jilin, 130012, China.
Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China.
Biomaterials. 2020 Sep;254:120139. doi: 10.1016/j.biomaterials.2020.120139. Epub 2020 May 23.
Development of cell-based therapeutic systems has attracted great interest in biomedicine. In vivo cell tracking by fluorescence provides indispensable information for further advancing cell therapy in clinical applications. However, it is still challenging in many cases because of the limited light penetration depth as well as the variations in fluorescent probes, cell lines, and labeling brightness. Here, we designed highly fluorescent polymer dots (Pdots) with far-red-light absorption and near-infrared (NIR) emission for cell tracking. The Pdots consisted of a donor-acceptor polymer blending system where intra-particle energy transfer yielded a narrow-band emission at 800 nm with a high quantum yield of ~0.22. We investigated biocompatibility and cell labeling brightness of the Pdots coated with cell penetrating peptides. Flow cytometry indicated that the cell-labeling brightness of both stem cells and cancer cells increased as much as ~4 orders of magnitude comparing the intensity measurements of labeled cells and controls. Yet, in vivo cell tracking results revealed distinctive fluorescence distribution for the same number of cells that were administered into mice through the tail vein. The stem cells initially accumulated in the lung and remained for seven days, whereas the cancer cells tended to be cleared by the liver in four days. The difference is likely due to the fact that cancer cells are easily attacked by the immune system, whereas stem cells have low immunogenicity. Results obtained herein confirm that NIR-fluorescent Pdots are promising platforms for in vivo cell tracking in small animals.
基于细胞的治疗系统的发展在生物医学领域引起了极大的关注。通过荧光进行体内细胞追踪为在临床应用中进一步推进细胞治疗提供了不可或缺的信息。然而，由于光穿透深度有限以及荧光探针、细胞系和标记亮度的变化，在许多情况下这仍然具有挑战性。在此，我们设计了具有远红光吸收和近红外（NIR）发射的高荧光聚合物点（Pdots）用于细胞追踪。Pdots由供体-受体聚合物共混体系组成，其中粒子内能量转移产生了800nm处的窄带发射，量子产率高达约0.22。我们研究了涂有细胞穿透肽的Pdots的生物相容性和细胞标记亮度。流式细胞术表明，与标记细胞和对照的强度测量相比，干细胞和癌细胞的细胞标记亮度都增加了约4个数量级。然而，体内细胞追踪结果显示，通过尾静脉注射到小鼠体内的相同数量的细胞具有独特的荧光分布。干细胞最初聚集在肺部并停留7天，而癌细胞在4天内倾向于被肝脏清除。这种差异可能是由于癌细胞容易受到免疫系统攻击，而干细胞具有低免疫原性。本文获得的结果证实，近红外荧光Pdots是用于小动物体内细胞追踪的有前途的平台。
