Low-pH preconditioned macrophage-derived extracellular vesicles enable targeted and enhanced paclitaxel therapy in gastric cancer

Figure 1 Preparation, characterization, and tumor-targeting ability of low-pH preconditioned macrophage-derived extracellular vesicles. A: Schematic illustrating the generation of low-pH preconditioned macrophage-derived extracellular vesicles (EVs); B: Representative transmission electron microscopy image of low-pH preconditioned macrophage-derived extracellular vesicles (LP-EV). Scale bar: 100 nm; C: Western blot analysis of EV marker proteins (ALIX, CD9, CD63); D: Nanoparticle tracking analysis showing the size distribution and zeta potential of LP-EV; E: Stability assessment of LP-EV stored in PBS or PBS containing 10% fetal bovine serum at 4 °C for up to 7 days; F: Confocal microscopy images showing MKN45 gastric cancer cells after incubation with DiI-labeled control EVs (C-EV) or LP-EV (red). Nuclei were stained with DAPI (blue), and F-actin was stained with phalloidin (green). Scale bar: 10 μm; G: Representative in vivo fluorescence images of MKN45 tumor-bearing nude mice at indicated time points after intravenous injection of DiR-labeled C-EV or LP-EV; H: Quantification of fluorescence intensity in tumor regions from G (n = 3); I: Representative ex vivo fluorescence images of major organs and tumors harvested 72 hours post-injection. LP-EV: Low-pH preconditioned macrophage-derived extracellular vesicles; C-EV: Control extracellular vesicles; FBS: Fetal bovine serum.