Expansion of induced pluripotent stem cells under consideration of bioengineering aspects: part 2

The manufacturing of allogeneic cell therapeutics based on human-induced pluripotent stem cells (hiPSCs) holds considerable potential to revolutionize the accessibility and affordability of modern healthcare. However, achieving the cell yields necessary to ensure robust production hinges on identifying suitable and scalable single-use (SU) bioreactor systems. While specific stirred SU bioreactor types have demonstrated proficiency in supporting hiPSC expansion at L-scale, others, notably instrumented SU multiplate and fixed-bed bioreactors, remain relatively unexplored. By characterizing these bioreactors using both computational fluid dynamics and experimental bioengineering methods, operating ranges were identified for the Xpansion^® 10 and Ascent™ 1 m² bioreactors in which satisfactory hiPSC expansion under serum-free conditions was achieved. These operating ranges were shown not only to effectively limit cell exposure to wall shear stress but also facilitated sufficient oxygen transfer and mixing. Through their application, almost 5 × 10⁹ viable cells could be produced within 5 days, achieving expansion factors of up to 35 without discernable impact on cell viability, identity, or differentiation potential. Key Points •Bioengineering characterizations allowed the identification of operating ranges that supported satisfactory hiPSC expansion •Both the Xpansion^® 10 multiplate and Ascent™ 1 m² fixed-bed reactor accommodated the production of almost 5 × 10⁹ viable cells within 5 days •Exposing the hiPSCs to a median wall shear stress of up to 8.2 × 10^-5 N cm^-2 did not impair quality.