Figure 2.

Preparation of EVs loaded with miR-150-3p and surface modified with iRGD-targeting peptide (iEV-150) and characterization of their enhanced melanoma cell-targeting ability. A TEM images of engineered EVs (scale: 100 nm). B NTA showing the size distribution of engineered EVs. C Western blot analysis of EV markers (CD9, CD63, CD81, and HSP70) and a negative marker (calnexin) in EV-150 and iEV-150. D, E qRT‒PCR analysis of miR-150-3p levels in EVs from different treatments (D) and in iEV-NC vs. iEV-150 (E). F Confocal microscopy of PKH67-labeled EV-150 and iEV-150 uptake by A375 and A875 cells (scale: 25 μm). G TEM image showing internalized EV-like structures (red arrows) in melanoma cells after incubation with EV-150 or iEV-150 (scale: 2 μm). H Flow cytometry analysis of FAM-labeled EV uptake by melanoma cells. I Distribution of DIR-labeled engineered iEV-150 and EV-150 in mouse melanoma models at 3 h, 6 h, and 9 h after tail vein injection (5 × 10¹⁰ particles), analyzed using an in vivo imaging system (IVIS). Each mouse was imaged individually, with 3 mice per group. J Analysis of fluorescence intensity in mice in vivo. K IVIS fluorescence imaging of major organs in mice at 9 h. L Fluorescence intensity analysis of mouse tumors. M, N Intratumoral distribution of EVs in melanoma tissue sections (scale: 100 μm). O H&E staining of major organs after tail vein injection of iEV-150 (5 × 10¹⁰ particles per dose) or PBS into mice. Injections were administered on Days 7, 10, 13, 16, and 19. Tissues were collected at the endpoint and stained with hematoxylin and eosin (H&E). Scale bar = 100 μm. P-R Serum biomarkers of liver (ALT, AST) and kidney (creatinine) function in treated mice (n = 6/group). Mean ± SD, *p < 0.05; **p < 0.01; ***p < 0.001; ns, not significant.