CAS Key Laboratory of Molecular Nanostructure and Nanotechnology, Beijing National Research Center for Molecular Sciences, CAS Research/Education Center for Excellence in Molecule Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Department of Medical Oncology, Peking University International Hospital, Beijing 102206, P. R. China.
Nanoscale. 2019 May 28;11(20):10106-10113. doi: 10.1039/c9nr01589b. Epub 2019 May 15.
Tumor-derived exosomes have emerged as promising cancer biomarkers and attracted increasing interest in non-invasive cancer diagnosis and treatment monitoring. However, the identification and quantification of exosomes in clinical samples such as blood remains challenging due to the difficulty in trade-off between recognition specificity and isolation efficiency. Here we have developed an aptamer-based fluorescence polarization assay for exosome quantification, which is a separation-free, amplification-free and sensitive approach enabling direct quantification of exosomes in human plasma. While the key specificity of this assay is based on the aptamer's inherent affinity to membrane proteins on exosomes, exosomes' inherent huge mass/volume acts as mass-based fluorescence polarization amplifier. Our assay allows quantitative analysis of exosomes in the range of 5 × 10 to 5 × 10 particles per μL with a detect limitation of 500 particles per μL for the cell line deprived exosomes. The total assay time is about 30 min with just one mix-and-read step to achieve high sensitivity. We have also demonstrated quantification of exosomes from lung cancer patients and healthy donors in clinical samples. This work describes a new and simple liquid biopsy assay to directly detect exosomes in the biological matrix, which facilitates cancer diagnosis and therapy monitoring.
肿瘤来源的外泌体已成为有前途的癌症生物标志物，并在非侵入性癌症诊断和治疗监测方面引起了越来越多的关注。然而，由于识别特异性和分离效率之间的权衡难题，临床样本（如血液）中外泌体的鉴定和定量仍然具有挑战性。在这里，我们开发了一种基于适体的荧光偏振测定法来定量外泌体，这是一种无需分离、无需扩增且灵敏的方法，可直接定量人血浆中的外泌体。虽然该测定法的关键特异性基于适体对外泌体上膜蛋白的固有亲和力，但外泌体固有的巨大质量/体积充当基于质量的荧光偏振放大器。我们的测定法允许在 5×10 至 5×10 个颗粒/μL 的范围内进行外泌体的定量分析，对于细胞系剥夺的外泌体，检测限为 500 个颗粒/μL。整个测定法的总时间约为 30 分钟，只需一步混合和读取即可实现高灵敏度。我们还在临床样本中证明了来自肺癌患者和健康供体的外泌体的定量。这项工作描述了一种新的简单的液体活检测定法，可直接在生物基质中检测外泌体，从而促进癌症诊断和治疗监测。
