Center of Clinical Experiments, Changhai Hospital, Second Military Medical University, Shanghai 200433, China.
Department of Chemistry and Institute of Biomedical Sciences, Fudan University, Shanghai 200433, China.
Talanta. 2018 Jul 1;184:219-226. doi: 10.1016/j.talanta.2018.02.083. Epub 2018 Mar 29.
Exosomes have proved to be an effective cancer biomarker with significant potential, and several cell-specific molecules have been found in colorectal cancer (CRC) exosomes. Nevertheless, it is challenging to use exosomes in clinical lab diagnostics due to their nanoscale and the lack of a convenient and effective detection platform. Here, we developed a DNase I enzyme-aided fluorescence amplification method for CRC exosome detection, based on graphene oxide (GO)-DNA aptamer (CD63 and EpCAM aptamers) interactions. The fluorescence of fluorophore-labeled aptamers quenched by GO, recovered after incubation with samples containing CRC exosomes. The DNase I enzyme digested the single-stranded DNA aptamers on the exosome surface and the exosomes were able to interact with more fluorescent aptamer probes, resulting in an increase of signal amplification. The limit of detection for CRC exosomes is 2.1 × 10 particles/μl. Consequently, a rapid and effective method with high sensitivity was established. The method was verified in 19 clinical blood serum samples to distinguish healthy and CRC patients, showing significant diagnostic power. Moreover, it can be expanded to other kinds of cancer exosomes, in addition to CRC.
外泌体已被证明是一种具有重要潜力的有效癌症生物标志物，在结直肠癌 (CRC) 外泌体中发现了几种细胞特异性分子。然而，由于其纳米尺度以及缺乏便捷有效的检测平台，外泌体在临床实验室诊断中的应用具有挑战性。在这里，我们开发了一种基于氧化石墨烯 (GO)-DNA 适体（CD63 和 EpCAM 适体）相互作用的 CRC 外泌体检测的 DNA 酶 I 酶辅助荧光扩增方法。被 GO 猝灭的荧光标记适体的荧光在与含有 CRC 外泌体的样品孵育后恢复。DNase I 酶消化外泌体表面的单链 DNA 适体，并且外泌体能够与更多荧光适体探针相互作用，从而增加信号放大。CRC 外泌体的检测限为 2.1×10 个颗粒/μl。因此，建立了一种快速、有效的高灵敏度方法。该方法在 19 份临床血清样本中得到验证，可区分健康个体和 CRC 患者，具有显著的诊断能力。此外，它可以扩展到其他类型的癌症外泌体，而不仅仅是 CRC。
