The subject invention concerns novel and translatable materials and methods for expansion of stem cells, such as mesenchymal stem cells (MSC), that significantly improve translational success of the cells in the treatment of various conditions, such as
stroke. The subject invention utilizes
cell self-aggregation as a non-genetic means to enhance their therapeutic
potency in a
microcarrier bioreactor. The subject invention integrates a
cell aggregation process in a scalable
bioreactor system. In one embodiment of the method, thermally responsive microcarriers (TRMs) are utilized in conjunction with a
bioreactor system. Cells are cultured in a container or vessel in the presence of the TRMs wherein cells adhere to the surface of the TRMs. Once cells are adhered to the TRMs they can be cultured at a suitable temperature for
cell growth and expansion, e.g., at about 37° C. After a period of time sufficient for
cell growth and expansion on the TRMs, the
cell culture temperature is reduced so that the cells detach from the TRMs. The detached cells are allowed to form cell clusters that are then cultured under conditions such that the clusters aggregate to form 3D aggregates. The 3D aggregates can be collected and treated to dissociate the cells (e.g., using enzymatic treatment, such as
trypsinization). Dissociated cells can then be used for
transplantation in methods of treatment or for
in vitro characterization and study.