DNA Nanowire Guided-Catalyzed Hairpin Assembly Nanoprobe for In Situ Profiling of Circulating Extracellular Vesicle-Associated MicroRNAs

Extracellular vesicle-associated miRNAs (EV-miRNAs) are emerging as a new type of noninvasive biomarker for disease diagnosis. Their relatively low abundance, however, makes accurate detection challenging. Here, we designed a DNAnanowire guided-catalyzed hairpin assembly (NgCHA) nanoprobe for profiling EV-miRNAs. NgCHA showed high penetrability to EVs, which allowed rapid delivery of the probes into EVs. In the presence of targeted miRNAs within EVs, afluorescent signal could be generated and amplified by confining the catalytic hairpin assembly system within the nanowires, thus greatly enhancing theanalytical sensitivity. We showed that EV-miRNAs from various cell lines could be accurately quantified by NgCHAin situ. By usinga four-EV-miRNA panel, this platform can identify patients with breast cancer at an early stage with 95.2% sensitivity and 86.7%specificity. Its applications for risk assessment as well as cancer type prediction were also successfully demonstrated. This platform issensitive, low-cost, and simple compared with current methods. It may thus serve as a promising tool for the noninvasive diagnosis and monitoring of cancers and other diseases through EV-miRNA profiling