A dual-signal amplification platform for sensitive fluorescence biosensing of leukemia-derived exosomes. Issue 43 (29th October 2018)

• Record Type: Journal Article
• Authors: Huang, Lin; Wang, Dian-Bing; Singh, Netrapal; Yang, Fang; Gu, Ning; Zhang, Xian-En
• Is Part Of: Nanoscale. Volume 10:Issue 43(2018)
• Page Start: 20289
• Page End: 20295
• Publication Date: 2018-10-29
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/c8nr07720g
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : We report a rolling circle amplification and nicking endonuclease-assisted dual signal amplification fluorescent biosensor for exosome detection. Abstract : Exosomes as nanosized biomarkers hold great potential for the diagnosis of cancer. However, the low concentration of cancer-derived exosomes present in biofluids makes early diagnosis strenuous. Here, we developed a fluorescent biosensing platform, namely a dual signal amplification, for the ultrasensitive detection of leukemia cell-derived exosomes. The protocol consists of three steps: first, leukemia-derived exosomes containing CD63 and nucleolin were captured by anti-CD63 antibody modified magnetic bead conjugates (MB-CD63); then, a DNA primer comprising a nucleolin-recognition aptamer (AS1411) was applied to bind the exosomes which further initiated a rolling circle amplification (RCA) reaction to generate many repeat sequences for hybridization with gold nanoparticle (GNP)–DNA–fluorescent dye (FAM) conjugates (GNP–DNA–FAM); finally, nicking endonuclease (Nb·BbvCI) assisted target recycling was introduced. As a result, FAM was released from GNP–DNA–FAM conjugates, transformed from the quenching state to the emission state and thus fluorescence signals continuously accumulated. With this dual signal amplification platform, as low as 1 × 10 2 particles per μL exosomes could be detected. Furthermore, we have successfully applied this method for the detection of exosomes in spiked serum samples, indicating a promising tool for clinical application.