High-Yield Isolation of Stem Cell-Derived Extracellular Vesicles Using a Gold Nanoparticle-Enhanced SiO₂ Immunoaffinity Platform.

Extracellular vesicles (EVs) produced by stem cells are nanoscale carriers of bioactive compounds with regenerative and immunomodulatory capabilities similar to those of their parent cells. Their therapeutic potential outperforms traditional stem cell therapies by lowering hazards such tumorigenicity and allowing for precise delivery. To provide a high-efficiency platform for selectively isolating stem cell EVs from minimal serum quantities while overcoming the constraints of traditional approaches such as ultracentrifugation, we developed an immunoaffinity-based capture system utilizing SiO₂ wafers functionalized with gold nanoparticles (GNPs), polyethylene glycol (HS-PEG-COOH), and stem cell-specific antibodies. The platform was evaluated to isolate EVs from 20 μL serum samples. The technique efficiently and selectively isolates EVs, including stem cell-derived subtypes, with yields of up to 10⁸ particles. Western blot testing demonstrated high purity and low protein contamination, demonstrating the capture mechanism's selectivity. This nanoparticle-enhanced platform allows for scalable, high-purity EV extraction from small sample volumes, which aids in downstream molecular analysis and therapeutic development. Its capacity to distinguish across EV subtypes has potential in personalized medicine, regenerative therapies, and non-invasive diagnostics.