Simple Fusion Method Developed to Load Large Drugs into Exosomes

A research team at the Korea Institute of Science and Technology (KIST), led by Hojun Kim and Hong Nam Kim, has created a novel technique to load large biomolecules such as mRNA into exosomes, overcoming a key challenge in drug delivery. Exosomes are natural vesicles used in cell communication that hold great promise as drug carriers because they can target specific cells and tissues. However, loading large molecules into their densely packed, cholesterol-rich membranes has proven difficult with conventional methods like electroporation or chemical treatments, which often damage both the cargo and the exosomes, limiting efficiency and complicating purification.

The new approach, detailed in Nature Communications, uses lipid-based nanoparticles called cubosomes, which mimic the fusion structure of cell membranes and naturally fuse with exosomes. By simply mixing cubosomes carrying mRNA with exosomes at room temperature for ten minutes, the team achieved efficient fusion with over 98% of the mRNA successfully encapsulated inside exosomes. Importantly, this method preserves the structural integrity and biological function of the exosomes, without requiring specialized equipment or complex procedures.

Significantly, these engineered exosomes were able to cross the blood-brain barrier, a major obstacle in drug delivery. The researchers also observed a "homing" effect, where exosomes preferentially return to the cells they originated from, enhancing targeted delivery to diseased tissues. This feature supports the potential use of this technology for precision medicine applications.

The method’s simplicity and adaptability make it suitable for clinical settings, allowing easy mixing of therapeutic molecules with exosomes at the point of care. It can carry large payloads while maintaining exosome function, expanding possibilities to treat complicated diseases such as neurological disorders, cancer, and autoimmune conditions.

Dr. Kim highlighted the practical impact of this technique, stating, "This technology allows medical professionals to easily combine exosomes and therapeutic molecules at the clinical site, making it a meaningful step toward realizing personalized medicine.”