Dissolvable Microcarriers Allow Scalable Expansion And Harvesting Of Human Induced Pluripotent Stem Cells Under Xeno-Free Conditions

Abstract

The development of bioprocesses capable of producing large numbers of human induced pluripotent stem cells (hiPSC) in a robust and safe manner is critical for the application of these cells in biotechnological and medical applications. Scalable expansion of hiPSC is often performed using polystyrene microcarriers, which have to be removed from the cell suspension using a separation step that causes loss of viable cells. In this study, application of novel xeno-free dissolvable microcarriers (DM) for an efficient and integrated expansion and harvesting of hiPSC is demonstrated. After an initial screening under static conditions, hiPSC culture using DM is performed in dynamic culture, using spinner-flasks. A maximum 4.0 ± 0.8-fold expansion is achieved after 5 days of culture. These results are validated with a second cell line and the culture is successfully adapted to fully xeno-free conditions. Afterwards, cell recovery is made within the spinner flask, being obtained a 92 ± 4% harvesting yield, which is significantly higher than the one obtained for the conventional filtration-based method (45 ± 3%). Importantly, the expanded and harvested hiPSC maintain their pluripotency and multilineage differentiation potential. The results here described represent a significant improvement of the downstream processing after microcarrier-based hiPSC expansion, leading to a more cost-effective and efficient bioprocess.

Keywords: dissolvable microcarriers; downstream processing; human induced pluripotent stem cells; spinner-flasks; xeno-free.