Evaluating the Effects of Drug-Loaded Macrophage-Derived Small Extracellular Vesicles in Breast Cancer Cells

Small extracellular vesicles (sEVs) are membrane-bound nanoparticles naturally secreted by cells and recognized for their ability to facilitate intercellular communication. Their nanoscale size, stability, and inherent biocompatibility make them promising candidates for drug delivery.1 This study investigates a graphene quantum dot (GQD) based platform for loading doxorubicin (Dox) into sEVs and evaluates its performance using macrophage-derived (RAW264.7) and fibroblast-derived (3T3) sEVs. sEVs were successfully isolated from RAW264.7 and 3T3 cell lines and characterized by nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), and Western blotting for key sEV markers including CD9, CD63, ALIX, and CD47. GQD/Dox complexes were formed via p-p stacking interactions and confirmed using fluorescence quenching. Integration of the GQD/Dox complex into sEVs was optimized at a GQD concentration of 15 µM and assessed through confocal imaging and permeation efficiency calculations. The resulting drug-loaded sEVs were assessed on MCF-7 breast cancer cells in vitro. Cell viability was assessed using a live/dead staining kit and CCK-8 assay, revealing a dose-dependent cytotoxic effect. Notably, RAW264.7 derived sEVs demonstrated slightly enhanced cytotoxicity compared to 3T3-derived sEVs, possibly due to differences in vesicle surface markers such as CD47. Overall, this work demonstrates the feasibility of combining sEVs with a GQD mediated drug loading platform for targeted cancer therapy. The platform’s adaptability to different vesicle sources and its effective delivery of doxorubicin highlights its potential for further preclinical exploration.