Postdoctoral Researcher Hannover Medical School Hannover, United States
Abstract: Human pluripotent stem cell (hPSCs) derivatives hold immense potential for advanced drug screening, in vitro disease modelling and regenerative therapies. However, the envisioned routine application of these cells will require robust and economically viable production processes, compatible with industry and regulatory standards. In the biopharmaceutical industry, instrumented stirred tank bioreactors (STBR) are widely used for mammalian cell cultivation. This platform has also been successfully adapted for matrix-free suspension culture of hPSCs and recently enabled advanced high cell density bioprocessing of hPSCs by metabolic control and in silico modelling by our group, including process scalability to up to a working volume of 500 mL. The potential working scales for future cell productions are anticipated to exceed 2,000 L. However, oxygen supply using the conventionally applied headspace gassing becomes increasingly difficult at higher process scales, revealing a potential bottleneck for further process upscaling. In addition, using conventional sparger technologies to supply enough oxygen, leads to viability decrease and even cell death and thus is not applicable with iPSCs. BioThrust has recently developed a novel, scalable bioreactor featuring a first-of-its-kind membrane stirrer technology, enabling advanced and more physiological oxygen transfer into the cultivation medium. This innovation offers a promising solution to mitigate oxygen depletion and cell death associated with bubble aeration, particularly at high cell densities or larger process scales. We have optimized the membrane stirrer for our established high-density hPSC culture strategy through stepwise improvements in its design. These refinements enable reproducible aggregation at process inoculation and ensure efficient oxygen delivery throughout the entire cultivation process.
