Yang Di, Guan Shanyue, Niu Yuefang, Xie Zheng, Zhou Shuyun, Qu Xiaozhong
College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China.
J Mater Chem B. 2018 Apr 21;6(15):2315-2322. doi: 10.1039/c8tb00278a. Epub 2018 Apr 3.
In this work, we synthesized a hypoxia responsive upconversion nanosensor by the conjugation of oxygen insensitive upconversion carbon dots (CDs) with an oxygen sensitive ruthenium(ii) complex (Rudb). The CD-Rudb conjugate was then PEGylated to mediate the formation of nano-sized assemblies of the resultant polymer probe (CD-Ru-mPEG) in aqueous solution. The strategy allows the oxygen sensitive probe (Rudb) to be excited by NIR irradiation and achieve upconverted emission through the Förster resonance energy transfer process from the CDs. The oxygen sensitivity of the ruthenium moiety was well-preserved in the polymeric aggregates because the PEG chains could prohibit the occurrence of self-quenching that may occur due to the close packing of the probes. Such an upconversion photoluminescence property makes the CD-Ru-mPEG nanosensor work as a biocompatible imaging system to monitor the oxygen level in cells and the hypoxic condition in vivo.
在本研究中，我们通过将对氧不敏感的上转换碳点（CDs）与对氧敏感的钌（II）配合物（Rudb）共轭，合成了一种缺氧响应型上转换纳米传感器。然后将CD-Rudb共轭物聚乙二醇化，以介导所得聚合物探针（CD-Ru-mPEG）在水溶液中形成纳米尺寸的聚集体。该策略使对氧敏感的探针（Rudb）能够通过近红外辐射激发，并通过来自CDs的Förster共振能量转移过程实现上转换发射。钌部分的氧敏感性在聚合物聚集体中得到了很好的保留，因为聚乙二醇链可以阻止由于探针紧密堆积可能发生的自猝灭。这种上转换光致发光特性使CD-Ru-mPEG纳米传感器成为一种生物相容性成像系统，用于监测细胞中的氧水平和体内的缺氧状态。
