Rapid and sensitive leukemia-derived exosome quantification via nicking endonuclease-assisted target recycling

• Published in: Analytical methods Vol. 13; no. 35; pp. 4001 - 4007
• Main Authors: Zhou, Mengyang, Li, Chao, Wang, Baolong, Huang, Lin
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 21.09.2021
• Subjects: Aptamers; Biomarkers; Biosensors; Blood plasma; Cancer; Deoxyribonucleic acid; Diagnosis; DNA; Exosomes; Fluorescence; Leukemia; Medical diagnosis; Nanoparticles; Nicking endonuclease
• ISSN: 1759-9660; 1759-9679
• DOI: 10.1039/d1ay00854d

Exosomes as fluid biomarkers hold great promise for noninvasive cancer diagnosis. However, a method for the rapid and convenient detection of exosomes is still a challenge because current analysis processes involve multiple steps and yield low sensitivity. Here, we developed a wash-free fluorescent biosensor for the rapid and sensitive quantification of exosomes by combining aptamer and nicking endonuclease (Nb·BbvCI). In this system, an aptamer–trigger complex was used as the recognition element; the trigger probe could be released, and it hybridized with gold nanoparticles (GNPs)–DNA–FAM conjugates, thereby resulting in Nb·BbvCI-assisted target recycling. As a result, our method allowed the quantification of exosomes with lower analysis time by using a cocktail containing an aptamer–trigger complex, Nb·BbvCI, and GNPs–DNA–FAM. A high sensitivity with a limit of detection (LOD) of 1.0 × 10 4 particles per μL could be achieved. Besides, this biosensor exhibited potential application for the quantification of exosomes in human plasma, facilitating the development of exosome-based noninvasive cancer diagnosis.