Microfluidic loading of verteporfin into extracellular vesicles for neuroblastoma therapy

Despite contributing to cancer progression, extracellular vesicles (EVs) could serve as potential drug delivery systems in cancer treatment, having the ability to dissolve water-insoluble drugs and facilitate targeted delivery. However, the clinical translation of EVs is still in its infancy. While traditional methods for EV modifications will remain relevant, microfluidic approaches are expected to replace benchtop methods. Taking advantage of lab-on-chip devices, passive cargo loading through microfluidic mixing and incubation may be an important strategy to produce functional engineered EVs. This study focuses on developing a microfluidic device to generate EVs loaded with verteporfin (VP), a hydrophobic porphyrin with potential applications in neuroblastoma (NB) therapy, aiming to enhance its therapeutic effectiveness. The platform ensures perfect mixing and tunable incubation time for mesenchymal stem cell-derived EVs and VP, demonstrating a significantly higher loading efficiency than traditional methods, while operating under gentle conditions that preserve EV integrity and functionality, unlike other microfluidic techniques that involve harsh mechanical or chemical treatments. The VP-loaded EVs (VP-EVs) can then be easily recovered, making them available for subsequent analysis and use. MTT assay confirmed that VP-EVs are more efficient than free VP in reducing the viability of a NB cell line. Finally, immunofluorescence assay and western blot demonstrated a greater reduction in YAP expression after treatment with VP-EVs in an NB cell line when compared to free VP. Being both non-destructive and straightforward, this microfluidic loading technique facilitates its adaptability to a wide spectrum of therapeutic compounds. As a versatile tool, microfluidic technology will help to fully unlock the potential of EVs for speeding up precision medicine and disease treatment.