Guo Yuehua, Cao Qihang, Feng Qiumei
Research Center of Clinical Medicine, Affiliated Hospital of Nantong University, Nantong, 226001, China.
School of Chemistry and Materials Science, Jiangsu Normal University, Xuzhou, 221116, China.
Anal Chim Acta. 2020 Oct 23;1135:55-63. doi: 10.1016/j.aca.2020.08.036. Epub 2020 Aug 27.
The detection of a small number of exosomes provides the possibility for early cancer diagnosis and prognosis. Here, a multi-signal amplified electrochemical sensing platform was explored for the ultrasensitive detection of tumor exosomes relying on catalytic hairpin assembly-triggered DNA walker, entropy beacon-based DNA assembly and Ag@C core-shell nanocomposites. In this work, the utilization of Ag@C nanocomposites as electrode interface effectively enhanced functional active sites and electron transfer capability. By designing a target-assisted entropy beacon-based DNA assembly, single exosome initiated the release of multiple special DNA sequences, which could be separated conveniently by magnet and then hybridize with the blocking DNA to liberate swing arm. DNA walker was activated with the assistance of catalytic hairpin assembly, introducing extensive electroactive methylene blue (MB) to electrode surface. Thus, the detection of exosomes was transferred into the measurement of the MB current, with a good liner range from 100 to 75 000 particles/μL. Furthermore, this constructed sensing system displayed acceptable reproducibility, long-term stability, favorable selectivity, and highlighting application potential in real samples.
少量外泌体的检测为癌症早期诊断和预后提供了可能。在此，基于催化发夹组装触发的DNA步行器、基于熵探针的DNA组装以及Ag@C核壳纳米复合材料，探索了一种多信号放大电化学传感平台用于超灵敏检测肿瘤外泌体。在这项工作中，利用Ag@C纳米复合材料作为电极界面有效增强了功能活性位点和电子转移能力。通过设计基于目标辅助熵探针的DNA组装，单个外泌体引发多个特殊DNA序列的释放，这些序列可通过磁体方便地分离，然后与封闭DNA杂交以释放摆动臂。在催化发夹组装的辅助下激活DNA步行器，将大量电活性亚甲基蓝（MB）引入电极表面。因此，外泌体的检测转化为MB电流的测量，线性范围良好，为100至75 000个颗粒/μL。此外，构建的传感系统具有可接受的重现性、长期稳定性、良好的选择性，并在实际样品中具有突出的应用潜力。
