In vitro expansion of embryonic stem cells in a fibrous bed bioreactor

Introduction: ES cells are considered a potential alternative source of cell therapy and tissue transplantation [1]. However, spontaneous differentiation often happens when embryonic stem cell is cultured in vitro [2]. When first isolated, it was believed that having murine embryonic fibroblasts as the feeder cell was essential for mouse ES cell maintenance [3]. However, if ES cells are used to treat human or veterinary patients, the feeder cells are the potential contamination source when harvesting ES cells in traditional 2-D culture. What is needed is the large scale expansion of undifferentiated embryonic stem cells without these feeder cells Thereby, it will supply enough amounts of ES cells for stem cell therapy. Most of current ES cell expansion works were done in 2-D culture system. This needs gelatin pre-coated surface and frequent passages to maintain their undifferentiated stage [4]. These labor intensive and time consuming work could not meet the projected high market demand. In this study, we tried to find an economic and scalable way to produce undifferentiated ES cells by replacing LIF with condition medium from STO cell culture and providing 3-D culture environment.