Dear Julia. Thank you for your question. MSC-derived exosome is an exciting area of research. I suggest that you directly contact the authors who have recently published in this area. I enclose two articles from Frontiers on the topic. I recommend contacting them. You could collect in this way more than one protocol and experiment with them until you develop your own than yield best outcomes. I see that you are from the UK, you may also be able to ask to visit them in their labs and learn their techniques. Many times, people will help and give you such an opportunity. Good luck with your work.