Journal: Journal of Extracellular Vesicles
Article Title: Unravelling Ligand Conjugation Performance in Extracellular Vesicles: A Quantitative Assessment of Lipid, Protein, and Membrane Modifications
doi: 10.1002/jev2.70174
Figure Lengend Snippet: The impact of ligand conjugation on cell uptake of mEVs‐Tf. (a) Schematic illustration of the principle for evaluating the correlation between ligand conjugation and cell uptake. (b) Confocal fluorescence microscopy analysis of the cell uptake of DiD‐labelled blank mEVs and the transferrin conjugated counterparts in the presence or absence of 50 mM free transferrin, respectively. HepG2 cells were incubated with DiD‐labelled (red) mEV‐Tf for 12 h, and stained with Hoechst 33342 (blue) for cell nuclei imaging. (c) Lysosome colocalization analysis of DiD‐labelled blank mEVs and mEVs‐Tf engineered by different methods. HepG2 cells were incubated with DiD‐labelled (red) mEV samples for 24 h, and stained with Hoechst 33342 (blue) and LysoTracker (green) for cell nuclei and lysosome imaging, respectively. (d) Semi‐quantitative analysis of the colocalization degree between mEVs and lysosomes using the Manders' colocalization coefficients M1 and M2. (e) Representative dot‐plots between particle size and ligand number of the mEVs‐Tf‐CF488 engineered by lipid modification (panel‐i), protein modification (panel‐ii) and membrane insertion (panel‐iii), respectively. The transferrin concentration was 50 µM for all three samples. (f), (g) Percentage of Tf‐CF488 positive particles (f) and ligand density (g) of the mEVs‐Tf‐CF488 engineered by different methods with increasing input concentrations of Tf‐CF488. (h) FCM analysis of the impact of ligand density on the cell uptake degree of the DiD‐labelled mEVs‐Tf‐CF488 engineered by lipid modification (panel‐i), protein modification (panel‐ii) and membrane insertion (panel‐iii), respectively. (i,j) The relationship between cell fluorescence intensity (FL‐DiD) and input concentration of Tf‐CF488 (i), and ligand density (j) for DiD‐labelled mEVs‐Tf‐CF488 engineered by different methods.
Article Snippet: The concentration of accessible transferrin conjugated on mEVs was measured by a human transferrin ELISA kit (MultiSciences).
Techniques: Conjugation Assay, Fluorescence, Microscopy, Incubation, Staining, Imaging, Modification, Membrane, Concentration Assay