Ask the Expert – Addressing Shear Stress in Bioreactors

By on October 23, 2017
Ask the Expert

Introduction of oxygen to cell culture media via sparging is critical for efficient bioreactor operation. Since oxygen is sparingly soluble in culture media, efficient sparging methods are important to ensure cells have enough oxygen for growth and productivity. However, hydrodynamic stress in bioreactors and specifically shear caused by sparging, can present a challenging issue in commercial biopharmaceutical manufacturing.

A solution was found in the use of Poloxamer 188, a surface-active, non-ionic polymer that when added to cell culture media acted as a shear protectant. Poloxamer 188 became a standard ingredient in cell culture media for commercial production. However, as cell culture technology improved including process intensification, which increased cell densities and productivities in fed-batch and perfusion modes, issues with poloxamer were reported. Issues included unexpected loss of cell density and viability in biopharmaceutical manufacturing. This loss could be traced back to lot-to-lot variation in the Poloxamer 188. This variation was a major problem and was the subject of several investigations to understand the source of the variation.

We recently published a Cool Tool, “Improved, High Quality Poloxamer 188 Produces Consistent Performance in Cell Culture, “ that discusses how MilliporeSigma addressed this issue by developing proprietary analytical and biological methods to identify the critical properties of Poloxamer 188. These methods were based on a reference library of over 100 blinded customer and supplier samples.

We asked, Jochen Sieck, Head of Perfusion Systems Lab, Life Science, BioProcessing R&D, Merck, if he would host an Ask the Expert session on the topic. Jochen was kind enough to agree to answer questions from readers this week on the topic of addressing shear stress in bioreactors and the use of cell culture optimized, Poloxamer 188 EMPROVE® EXPERT as a shear protectant

This Ask the Expert session is sponsored by MilliporeSigma and is hosted by Jochen Sieck. Jochen has more than 10 years of experience in mammalian cell culture, upstream process development, bioreactor characterization and scale-up. He studied Biotechnology and received his PhD in bioprocess engineering from ETH Zurich, working on Scale-Down Models of CHO fed-batch processes at Novartis. He stayed at Novartis for 2 years of Postdoc, working on perfusion process and medium development, before joining Merck in 2014. Since then, his team’s focus is perfusion medium development for customer as well as catalog products. Furthermore, his team investigates specific critical cell culture ingredients for their quality and impact on mammalian cells, targeting increase of reproducibility, reduced variability and improved quality. He has authored several journal articles and a textbook chapter on medium development for perfusion processes. Also, he is in the final stages of his MBA focusing on Innovation and Technology Management.

Please take advantage of the opportunity to ask our expert a question and participate in a lively discussion on shear stress in bioreactors.

Ask a Question or View Topic

Leave a Reply

Your email address will not be published. Required fields are marked *