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Upstream process intensification series: (Part 1) Reducing Batch Variability

Summary

Recently, we have launched a survey to identify what value the scientists are looking to have in their manufacturing pipeline. Based on the results of our survey, we have identified some specific dilemmas that will be discussed in our bioprocessing knowledge series.

Our first topic for this series is how to reduce batch variability in upstream bioprocessing, where  selecting the most optimal platform technology for your product is crucial. The key consideration for process development is process scalability, where there is no perfect parameter with the tremendous options available in bioprocessing.

To that end, Analysismode team is studying the cell expansion line and nutrients to select optimal scale-up strategy for our clients. Hence, we ask questions like: [1] Is the cell expanding differently when taken from different patients? [2] Does the cell have a high demand of oxygen? [3] What type of digital algorithmic tools needed to process the scale up? [4] Is computational fluid dynamics useful to understand the bioreactor physics? [5] Is process simulation informative in studying the cell behaviour? [6] How many inline and offline parameters can we correlate to improve batch quality? [7] What is the yearly amount of product that can be produced?

Optimizing the Cell Culture

It all starts from the Cell Culture: Cell line & Cell Culture Microenvironment!

The applications of cell culture is tremendous in the model systems to investigate the biology, biochemistry, physiology (e.g., ageing) and metabolism of wild-type cells and diseased cells. It can also be applied to screen novel chemicals, cosmetics, and drug compounds for their efficacy and assess drug cytotoxicity in specific cell types. Furthermore,  the cell culture using mammalian cells offers a host for viruses to replicate in vaccine production or tissue regeneration and transplantation, where hIPSCs, embryonic stem cells, and adult stem cells can differentiate into specialised cell types as replacement tissues or organs. And lastly in the field of gene therapy, where specific genes are engineered and expressed in cultured mammalian cells to aid in restoring dysfunctional genes in patients.

In that context, we would like to highlight that the choice of a cell line for cell culture depends heavily on the functional properties required of the cell mode. The cells can be: [A] Primary cells, such as fibroblasts obtained from skin biopsies that may be accompanied with many biosafety challenges, [B] Transformed cells, such as standardised cell lines derived from human or nonhuman species or (e.g., Chinese hamster ovary (CHO), HeLa, human umbilical vein endothelial cells (HUVEC)) that are maybe easier to set-up , and [C] Self-renewing cells, such as embryonic stem cells, induced pluripotent stem cells, neural and intestinal stem cells that act as physiologically representatives of in vivo mechanisms.

Moving forward to the other part of cell culture, which is the selection of suitable growth conditions for the chosen cell line. The cell culture microenvironment can be: [A] Biological fluids, including serum, plasma, lymph, and amniotic fluid, [B] Tissue extracts, including embryo, bone marrow, tumour, and liver extracts; [C] Plasma clots or coagulants. The common goal for all bench scientists is to create an environment that allows for maximum cell propagation. This is achieved mainly through the incubator (i.e., temperature, humidity, O2, and CO2 tensions) and the basal cell culture medium and its supplements. It is not only about providing nutrients like carbohydrates, vitamins, amino acids, minerals, growth factors, hormones, but also components that control physicochemical properties such as the culture’s pH and cellular osmotic pressure.

Perfusion Process in Cell Culture

This brings us to the final destination of the biomanufacturing process to realise productivity gains in upstream processes, where running perfusion cell culture operations are one way to achieve process scalability. A successful perfusion process is highly dependent on having an optimised cell culture media and process parameters for each cell line chosen. Hence, careful consideration is given to the choice of cell culture media to ensure a cost effective process. We partner with our customers to understand their objectives and challenges and design custom solutions to improve their process and develop a workflow of  high-performing perfusion media using small-scale models.

Special thanks to Cytiva and Amgen for their shared guidance and learnings.

As your partners, we always want to learn more about your needs & tackle your dilemmas in the upstream bioprocess. So Let’s discuss innovations at https://bit.ly/3gt4ywk

Additional Academic References:
[1]Segeritz, Charis-P., and Ludovic Vallier. “Cell Culture: Growing Cells as Model Systems In Vitro.” Basic Science Methods for Clinical Researchers (2017): 151–172.

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