Mesenchymal stem cells (MSCs) have attracted research interest due to their ability to induce tissue repair and reduce inflammation. More recently, their therapeutic benefits have been attributed to small membrane bound vesicles called extracellular vesicles (EVs) that they release. The implantation of MSC-EVs offers significant advantages over the implantation of viable MSCs. Their nonliving nature eliminates many of the safety concerns related to cell therapies and enables them to be stored and transported more efficiently.

There is a significant need to develop clinically applicable bioprocesses that can produce large numbers of therapeutically relevant MSC-EVs. This involves the translation of small-scale studies to large scale processes, which is limited by considerations such as the medium and platform in which the cells are cultured. Due to the novelty of the EV field, current research in this area is very limited, and thus the goal of this thesis was to evaluate the efficacy of producing MSC-EVs in a clinically relevant medium, and to gain insight into the impact of culture parameters needed for the scale-up of MSC-EVs.

This thesis demonstrated, for the first time, that functional MSC-EVs could be produced using a clinically relevant serum-free culture medium for the applications of articular cartilage repair, cerebral ischemia, and intracranial aneurysm repair. Further, it was found that functional MSC-EVs could be produced in scalable stirred suspension bioreactors. These studies were among the first to evaluate the use of such a platform for EV production and were the first to present a scalable model for EV production specifically for the applications of articular cartilage repair and cerebral ischemia. In addition, the culture of MSCs at physiological oxygen conditions was evaluated and found to enhance their angiogenic potential, without damaging physiological function, in the application of cerebral ischemia.

Finally, important considerations relevant to the upstream production of MSC-EVs were studied, including the confluence of cultured MSCs and the medium in which the EVs were isolated. This work enabled a proposed workflow for producing EVs in serum-free medium and will contribute highly to the development of clinically applicable bioprocesses aimed at producing MSC-EVs for applications in regenerative medicine.