A Fluorescence Assay for Exosome Detection Based on Bivalent Cholesterol Anchor Triggered Target Conversion and Enzyme-Free Signal Amplification

Exosomes are emerging as one of the most promising biomarkers for early disease diagnosis and prognosis. The significant challenges facing available methods include improving detection specificity sensitivity in complex biological samples. Herein, a fluorescence assay was established based on combination immunomagnetic separation two-step signal amplification strategy direct isolation subsequent exosomes. First, beads capture enrich exosomes via antibody-antigen reactions. Second, bivalent cholesterol (BC) anchors spontaneously insert into lipid bilayer bead-captured exosomes, forming to many effect. simultaneous recognition surface protein structure exosome significantly eliminates interference risk from free proteins. converts BC-anchors. Finally, sticky end BC-anchor acts initiator trigger enzyme-free DNA circuits secondary amplification. Under optimal conditions, highly sensitive selective achieved ranging 5.5 × 103 1.1 107 particles/?L with limit 1.29 particles/?L. Moreover, this method allows quantitative analysis several fluids satisfactory recovery rates (92.25-106.8%). Thus, approach provides sensitive, anti-interference platform isolating detecting