State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China.
Tibetan University of Tibetan Traditional Medicine, Lasa 850000, China.
Nanoscale. 2019 Sep 7;11(33):15589-15595. doi: 10.1039/c9nr04050a. Epub 2019 Aug 12.
Exosomes have been recognized as promising sources of biomarkers for early cancer diagnosis due to their important role in the occurrence and metastasis of cancer, and so the development of a sensitive low-cost detection method for exosomes is highly desirable. In this paper, we report a fluorescence method for the competitive detection of exosomes based on an aptamer specific to CD63 (an exosome transmembrane protein). Aptamer-modified magnetic beads were hybridized with a Cy3-labeled short sequence complementary to a region of the aptamer. In the presence of exosomes, the CD63 on the exosomes bound to the aptamer, resulting in the shedding of the short sequence into the supernatant. The quantity of the exosomes could be estimated by detecting the fluorescence intensity in the supernatant. This method could detect exosomes at a concentration as low as 1.0 × 10 particles per μL under optimal conditions, and the feasibility of the method for exosome detection in complex clinical samples was also proved using simulated serum samples. The detection cost and difficulty are significantly reduced compared to conventional methods, while ensuring sensitivity, and so this method provides a basis for subsequent exosome detection in specific cancer cells.
外泌体由于在癌症的发生和转移中具有重要作用，因此被认为是癌症早期诊断有前途的生物标志物来源，因此，非常需要开发一种灵敏、低成本的外泌体检测方法。在本文中，我们报道了一种基于针对 CD63（一种外泌体跨膜蛋白）的适体的荧光法用于外泌体的竞争性检测。适体修饰的磁性珠与 Cy3 标记的短序列杂交，该短序列与适体的一个区域互补。在存在外泌体的情况下，外泌体上的 CD63 与适体结合，导致短序列脱落到上清液中。通过检测上清液中的荧光强度，可以估计外泌体的数量。在最佳条件下，该方法可以检测到浓度低至 1.0×10 个颗粒/μL 的外泌体，并且使用模拟血清样品还证明了该方法在复杂临床样品中外泌体检测的可行性。与传统方法相比，该方法的检测成本和难度大大降低，同时确保了灵敏度，因此为后续在特定癌细胞中外泌体的检测提供了依据。
