An implantable electrical bioreactor for enhancement of cell viability

Low survival of injected cells which are prepared by ex-vivo culture is main obstacle in cell-based tissue regeneration. To elevate cell adaptation, we designed an implantable electrical bioreactor where human mesenchymal stromal cells (hMSCs) can be cultured and stimulated electrically. Bioreactor was composed of biocompatible cylindrical Teflon body containing a flexible polyimide electrode and implantable stimulator. The Teflon body has about 300 holes with a diameter of 300um for effective nutrients supply inside the bioreactor and has a length of 17mm and a diameter of 8mm for implantation. After hMSCs seeded on the collagen sponge that serves as scaffold to form a bone tissue graft, they are cultured in the bioreactor with biphasic electric current (BEC) stimulation. BEC stimulation with amplitude of 20/40uA, duration of 100us and a frequency of 100Hz was applied for one week in the early stage of cultivation. Subsequently, after hMSCS were cultured for another week without electrical stimulation, cell response such as cell proliferation, cell attachment and gene expression are evaluated. In vitro and In vivo culture of hMSCs showed 19% and 22% increase in cell proliferation at stimulated groups, compared to unstimulated control. The expression of type I collagen increased significantly at stimulated group. These results suggest that the usage of implantable electrical bioreactor can be a good strategy to enhance the efficiency of stem cell-based tissue engineering.