An electrochemiluminescent aptasensor for amplified detection of exosomes from breast tumor cells (MCF-7 cells) based on G-quadruplex/hemin DNAzymes

• Published in: Analyst (London) 2019-06, Vol.144 (11), p.3668-3675
• Main Authors: Qiao, Bin, Guo, Qunqun, Jiang, Juqian, Qi, Yunlong, Zhang, Hui, He, Bangshun, Cai, Chenxin, Shen, Jian
• Format: Article
• Language: English
• ISSN: 0003-2654; 1364-5528
• DOI: 10.1039/c9an00181f

Exosomes are non-invasive biomarkers for cancer diagnosis. Herein, we describe an electrochemiluminescent (ECL) aptasensor for the detection of exosomes from breast tumor cells. Mercaptopropionic acid (MPA)-modified Eu 3+ -doped CdS nanocrystals (MPA-CdS:Eu NCs) and H 2 O 2 were used as ECL emitters and coreactant, respectively. The exosomes are recognized and captured by the CD63 aptamer, and then form a G-quadruplex/hemin DNAzyme, which efficiently catalyzes the decomposition of H 2 O 2 , resulting in the decreased ECL signal of MPA-CdS:Eu NCs. The exosomes from breast tumor cells (MCF-7 cells) can be detected in the range of 3.4 × 10 5 to 1.7 × 10 8 particles per mL. The limit of detection (LOD) was estimated to be 7.41 × 10 4 particles per mL at a signal-to-noise ratio of 3. The aptasensor has been successfully used to detect exosomes in the serum. An electrochemiluminescent aptasensor was developed for the sensitive detection of exosomes from breast tumor cells (MCF-7 cells).