Dual Rolling Circle Amplification- Assisted Single-Particle Fluorescence Profiling of Exosome Heterogeneity for Discriminating Lung Adenocarcinoma from Pulmonary Nodules

Exosomes secreted by tumor cells carry abundant molecular biomarkers that reflect the status of their originating cells.These tumor-derived exosomes(TDEs)have emerged as attractive diagnostic targets.However,the identification and characterization of highly heterogeneous TDEs remain practically challenging.Here,we report a dual rolling circle amplification(DRCA)-assisted approach for the selective encapsulation of single TDEs for fluorescence microscopic and flow cytometric analysis.TDEs have been targeted by aptamers that recognized their surface tumor marker and exosomal marker CD63,following DRCA that produced entangling polymeric DNA chains,resulting in facile particle enlargement that allows single-particle fluorescence profiling of exosome heterogeneity.We have demonstrated the use of a dual-marker positive ratio for exosome differentiation and applied division and multiplication operations for normalized andmagnified marker heterogeneity analysis.We further applied this assay to distinguish lung adenocarcinoma and pulmonary nodule patients and found an accuracy of 90%.We anticipate promising transformations of this straightforward assay into clinically implantable diagnostic methods.