Exosome clocked hybrid nanosystem for targeted TNBC therapy

Background: Metastasis is the leading cause of death in breast cancer worldwide. In recent years, it has been found that mesenchymal stem cells (MSC) cells and their exosomes play a role in the tumor microenvironment and they may have tumor homing properties. Using this information, our plan was to bioengineer MSC exosome-coated drug loaded polymeric nanoparticles to deliver our chemotherapeutic drug. Methods: To isolate the MSC exosomes we grew the cells in exosome free media and used ultracentrifugation with the highest speed at 100,000 g for isolation. We used Dynamic Light Scattering (DLS) for size analysis, polydispersity index (PDI) and zeta potential (ZP). PLGA polymeric nanoparticles were made using the Nanoassembler which uses microfluidics to make nanoparticles. Their size, PDI and ZP was also obtained using DLS and NTA. To make the coated NP we used the extrusion method. Results: The MSC exosomes and NP had the expected size. Our exosome sample was positive for exosomal proteins and negative for all other extracellular vesicles. After extrusion the ZP of our sample tells us that our sample was coated in exosomal membrane. Our sample was future purified using centrifugation and were loaded with Doxorubicin. Conclusion: We were able to make MSC exosome-coated drug loaded polymeric nanoparticles and show that they were stable and uniform in size. In the future we plan to do more cell studies to look at cell viability and toxicity as well as more compressive animal studies.