Fig. 2: Capture and surface labeling of tumor-derived EVs.
From: Single extracellular vesicle imaging via rolling circle amplification–expansion microscopy
A Schematic of dual-screening approach used to detect EpCAM+ PD-L1+ tumor-derived EVs in biological fluids. EpCAM+ EVs are captured by an EpCAM-specific aptamer (apt) bound to a thiol-modified DNA (SH-DNA) conjugated to the assay slide, incubated with a PD-L1-specific SP that serves as a RCA template, and then released by Nb.BbvCI cleavage of the nanocomplex. B Representative images and graph of FAM signal detected on chips hybridized with increasing FAM-labeled nanocomplex concentrations, before and after digestion with Nb.BbvCI treatment (pre- and post-dig; scale bar = 50 μm; mean ± standard deviation (SD) values; n = 3 biological replicates/group). Source data are provided as a Source Data file. C Representative images of A375 and MCF-7 cell PD-L1 SP/RCA (FAM) and membrane (DiI) signal and their colocalization (scale bar = 25 μm). Representative of 3 biologically independent experiments. D Flow cytometry analysis of PD-L1 and EpCAM expression on EVs isolated from A375 (+/+), MCF-7 (−/+), and Jurkat (−/−) cells. Representative of 3 biologically independent experiments. E Representative images and alignment of PD-L1 and EV membrane signal on captured MCF-7 and A375 cell EVs as detected by PD-L1-specific SP/RCA (FAM) and lipid membrane (DiI) labeling, before and after Nb.BbvCI-mediated EV release (scale bar = 25 μm). Representative of 3 biologically independent experiments. Source data are provided as a Source Data file.
