A general strategy for detection of tumor-derived extracellular vesicle microRNAs using aptamer-mediated vesicle fusion

Tumor-derived extracellular vesicle (EV) microRNAs (miRNAs) are important biomarkers for clinical diagnosis and disease treatment monitoring. However, the need to lyse EVs makes most methods for detection of tumor-derived EV miRNA expensive, labour-intensive, and time-consuming. Inspired by natural vesicular transport, we here developed a general strategy for in situ detection of tumor-derived EV miRNAs using aptamer-mediated selective fusion (Apt-Fusion). Taking advantages of the high selectivity, rapid and general applicability of Apt-Fusion, this method exhibits significant sensitivity and selectivity for tumor-derived EV miRNAs in a lysis-free manner using conventional flow cytometry. Using this method, the level of miR-21 in PD-L1 positive EVs was quantified and found to effectively distinguish cancer patients from healthy volunteers; additionally, miR-21 in PD-L1 positive EVs was found for the first time to correlate with tumor burden. Overall, Apt-Fusion holds great potential to detect tumor-derived EV miRNAs and expand detection of EV multi-molecular compositions, offering a new avenue for cancer diagnosis and immunotherapy response monitoring. Inspired by natural vesicular transport, we developed a general strategy for in situ detection of tumor-derived extracellular vesicle (EV) microRNAs using aptamer-mediated selective fusion. The proposed strategy can distinguish tumor EVs from normal EVs by dual-selective recognition using aptamers and a molecular beacon. This method paves the way for rapid and efficient detection of EV miRNAs to diagnose cancers and monitor immunotherapy. • A general strategy for in situ detection of tumor-derived EV miRNAs. • An aptamer-mediated specific vesicle-fusion strategy. • The proposed could effectively distinguish cancer patients from healthy individuals, and the EV PD-L1 miR-21 level correlates with tumor burden.