Lacking of specific and sensitive early clinical biomarkers is one of the major contributors to high mortality of cancers. Recently, exosomes are microvesicles (30-100 nm) secreted by cancer cells which play an important role in tumor progression. Exosomes are considered as the best target in the liquid biopsy due to the advantages of wealth content, remarkable stability and their surface markers have the potential to assist primary and metastatic lesions location and thus are beneficial in the targeted therapy. Aptamers are viewed as artificial antibodies. It has several advantages including high binding affinity and specificity, easy and reproducible synthesis, long-term chemical stability and flexible modifications. Herein, we report the research of an aptamer-based biochip scanner for detection of exosomes secreted from A549 cells. Aptamers specific to exosome transmembrane protein CD63 are immobilized onto magnetic nanoparticles (MNPs) and probing strands pre-labeled with Cy3 are hybridized with aptamers modified on the surface of MNPs. The signal will be detected when the exosome spresent in the solution. The results show that the optimized concentration of aptamers reacted with MNPs is 20 µM; the time of probe hybridized with aptamers is 20 min and 300 exosomes per microliter have been detected. The method could be used to detect the amount of exosomes by signal strength quickly. Through the quantity difference of exosomes secreted from cancer cells and normal cells, cancer will be determined preliminarily. This method will lay the foundation for early diagnostic strategy.

Detection of exosomes using fluorescence detection based on competitive hybridization with aptamer

253rd National Meeting (2017)

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