Bioprocesses for recombinant protein production with mammalian cells are typically controlled for several physicochemical parameters including the pH and dissolved oxygen concentration (DO) of the culture medium. Here we studied whether these controls are ...

Elsevier2011

The PiggyBac transposon enhances the frequency of CHO stable cell line generation and yields recombinant lines with superior productivity and stability

Florian Maria Wurm, Lucia Baldi Unser, David Hacker

Generating stable, high-producing mammalian cell lines is a major bottleneck in the manufacture of recombinant therapeutic proteins. Conventional gene transfer methods for cell line generation rely on random plasmid integration, resulting in unpredictable ...

Wiley-Blackwell2011

CHO cell lines generated by PiggyBac transposition

Florian Maria Wurm, Lucia Baldi Unser, David Hacker, Virginie Bachmann

2011

A simple high-yielding process for transient gene expression in CHO cells

Florian Maria Wurm, Lucia Baldi Unser, David Hacker, Divor Kiseljak, Yashas Rajendra

Here we describe a simplified method for transient gene expression (TGE) in suspension-adapted Chinese hamster ovary (CHO) cells using polyethylenimine (PEI) for DNA delivery. Both the transfection and production phases of the bioprocess were performed at ...

Elsevier2011

Transient transfection of insect Sf-9 cells in TubeSpin® bioreactor 50 tubes

Florian Maria Wurm, David Hacker, Qiuling Xie, Xiao Shen

2011

TubeSpin bioreactor 50 for the high-density cultivation of Sf-9 insect cells in suspension

Florian Maria Wurm, Lucia Baldi Unser, David Hacker, Xiaowei Zhang, Qiuling Xie

Here we present the TubeSpin bioreactor 50 (TubeSpins) as a simple and disposable culture system for Sf-9 insect cells in suspension. Sf-9 cells had substantially better growth in TubeSpins than in spinner flasks. After inoculation with 106 cells/ml, maxim ...

Springer Netherlands2011

Transposon mediated co-integration and co-expression of transgenes in CHO-DG44 cells

Florian Maria Wurm, Lucia Baldi Unser, David Hacker, Sowmya Balasubramanian

2011

Reduced glutamine concentration improves protein production in growth-arrested CHO-DG44 and HEK-293E cells

Florian Maria Wurm, Lucia Baldi Unser, David Hacker, Divor Kiseljak, Yashas Rajendra

For most cultivated mammalian cells, glutamine is an essential medium component. However, glutamine consumption results in the production of ammonia, a cytotoxic byproduct. Here we investigated the effect of glutamine reduction on recombinant protein produ ...

Springer Netherlands2011

Innovative, Non-stirred Bioreactors in Scales from Milliliters up to 1000 Liters for Suspension Cultures of Cells using Disposable Bags and Containers – A Swiss Contribution

Florian Maria Wurm, Lucia Baldi Unser, Mathieu Benjamin Stettler, David Hacker, Stéphanie Tissot, Gilles Broccard, Xiaowei Zhang

Innovative mixing principles in bioreactors, for example using the rocking of a platform to induce a backwards and forwards 'wave' , or using orbital shaking to generate a 'wave' that runs round in a cylindrical container, have proved to be successful for ...

Schweizerische Chemische Gesellschaft2010

Valproic acid enhances recombinant mRNA and protein levels in transiently transfected Chinese hamster ovary cells

Florian Maria Wurm, Lucia Baldi Unser, David Hacker, Sarah Wulhfard

Valproic acid (VPA) is a small molecule that inhibits histone deacetylase activity. Here we report that VPA increases recombinant mRNA and protein levels in transiently transfected CHO DG44 cells. In the presence of VPA, transient recombinant antibody yiel ...

Elsevier2010

Hyperosmolarity enhances transient recombinant protein yield in Chinese hamster ovary cells

Florian Maria Wurm, Lucia Baldi Unser, David Hacker, Xiaowei Zhang, Isabel Fernandez Garcia

The effect of hyperosmolarity on transient recombinant protein production in Chinese hamster ovary (CHO) cells was investigated. Addition of 90 mM NaCl to the production medium ProCHO5 increased the volumetric yield of recombinant antibody up to 4-fold rel ...

Springer Netherlands2010

Generation of stable, high-producing cho cell lines by lentiviral vector-mediated gene transfer in serum-free suspension culture

Florian Maria Wurm, David Hacker, Agata Oberbek

Lentivirus-derived vectors (LVs) were studied for the generation of stable recombinant Chinese hamster ovary (CHO) cell lines. Stable pools and clones expressing the enhanced green fluorescent protein (eGFP) were selected via fluorescence-activated cell so ...

Wiley-Blackwell2010

Determination of a scale-up factor from mixing time studies in orbitally shaken bioreactors

Christos Comninellis, Florian Maria Wurm, Mohamed Farhat, David Hacker, Stéphanie Tissot

Efficient mixing in bioreactors is essential in order to avoid concentration gradients which can be harmful for mammalian cells. To study mixing and its scalability in orbitally shaken cylindrical bioreactors, we measured mixing times in containers with no ...

Elsevier2010

Efficient oxygen transfer by surface aeration in shaken cylindrical containers for mammalian cell cultivation at volumetric scales up to 1,000 liters

Florian Maria Wurm, Alfio Quarteroni, Mathieu Benjamin Stettler, Marco Discacciati, Nicola Parolini, David Hacker, Xiuwei Zhang, Marco Perrone, Dario De Sanctis

Cylindrical containers agitated by orbital shaking are being developed as simple and cost-effective bioreactor systems for the cultivation of mammalian cells. Here the oxygen transfer capacities of containers with nominal volumes from 50 mL to 2000 L were ...

2009

Use of Orbital Shaken Disposable Bioreactors for Mammalian Cell Cultures from the Milliliter-Scale to the 1,000-Liter Scale

Florian Maria Wurm, Alfio Quarteroni, Mathieu Benjamin Stettler, David Hacker, Xi Zhang

Driven by the commercial success of recombinant biopharmaceuticals, there is an increasing demand for novel mammalian cell culture bioreactor systems for the rapid production of biologicals that require mammalian protein processing. Recently, orbitally sha ...

2009

DNA delivery by microinjection for the generation of recombinant mammalian cell lines

Florian Maria Wurm, Madiha Derouazi, David Hacker, Sébastien Chenuet

Gene transfer methods for producing recombinant cell lines are often not very efficient. One reason is that the recombinant DNA is delivered into the cell cytoplasm and only a small fraction reaches the nucleus. This chapter describes a method for microinj ...

Humana Press2009

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