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David Hacker

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Publications associées (82)

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Virus-free transient protein production in Sf9 cells

Florian Maria Wurm, David Hacker, Lucia Baldi Unser, Xiao Shen

A method for virus-free transient gene expression from suspension-adapted Sf9 insect cells was developed with the gene of interest being expressed from a plasmid carrying the homologous region 5 enhancer (hr5) and the immediate early 1 (ie1) promoter from ...

Elsevier2014

DNA delivery with hyperbranched polylysine: A comparative study with linear and dendritic polylysine

Harm-Anton Klok, Florian Maria Wurm, David Hacker, Lucia Baldi Unser, Yashas Rajendra, Zuzana Kadlecova

PEI and polylysine are among the most investigated synthetic polymeric carriers for DNA delivery. Apart from their practical use, these 2 classes of polymers are also of interest from a fundamental point of view as they both can be prepared in different ar ...

Elsevier2013

Multiple glycerol shocks increase the calcium phosphate transfection of non-synchronized CHO cells

Florian Maria Wurm, David Hacker, Martin Bertschinger, Frédéric Grosjean

The exposure of CHO DG44 cells to an osmotic shock, after DNA uptake, results in a cellular volume decrease of approx. 55%. Repetitive osmotic shocks targeted different sub-populations of cells as was demonstrated using two different fluorescent reporter g ...

2006

Coordinated Effects of Sequence Variation on DNA Binding, Chromatin Structure, and Transcription

Bart Deplancke, David Hacker, Sebastian Martin Waszak, Sunil Kumar Raghav, Alisa Yurovsky, Gilles Udin

DNA sequence variation has been associated with quantitative changes in molecular phenotypes such as gene expression, but its impact on chromatin states is poorly characterized. To understand the interplay between chromatin and genetic control of gene regu ...

American Association for the Advancement of Science2013

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

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

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

Disposable 600-mL orbitally shaken bioreactor for mammalian cell cultivation in suspension

Florian Maria Wurm, David Hacker, Lucia Baldi Unser, Dominique Terry Monteil Jr, Saroj Ghimire

Orbitally shaken bioreactors (OSRs) support the efficient cultivation of mammalian cells in suspension at various scales of operation. Here we introduce a disposable culture vessel with a ventilated cap having a nominal volume of 600 mL (TubeSpin (R) biore ...

Elsevier2013

Genetic characterization of CHO production host DG44 and derivative recombinant cell lines

Florian Maria Wurm, David Hacker, Madiha Derouazi, Martin Bertschinger

The dihydrofolate reductase-deficient Chinese hamster ovary (CHO) cell line DG44 is the dominant mammalian host for recombinant protein manufacturing, in large part because of the availability of a well-characterized genetic selection and amplification sys ...

2006

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

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

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

Recombinant therapeutic protein production in cultivated mammalian cells: current status and future prospects

Florian Maria Wurm, David Hacker, Lucia Baldi Unser

Recombinant therapeutic proteins produced in mammalian cells represent a major class of biopharmaceuticals. In recent years, their demand has increased dramatically and is now driving the development of a variety of improvements to maximize their expressio ...

Elsevier2008

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

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

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

Scalable transient gene expression in Chinese hamster ovary cells in instrumented and non-instrumented cultivation systems

Florian Maria Wurm, David Hacker, Martin Jordan, Madiha Derouazi, Natalie Muller, Sarah Wulhfard

Cell expansion, gene transfer and protein production were all executed with a single serum-free, animal protein-free commercial medium designed for suspension-adapted Chinese hamster ovary cells (CHO DG44). This is a most important process to consider for ...

Kluwer Academic Publishers, Springer2007

Analysis of volumetric mass transfer coefficient (k(L)a) in small- (250 mL) to large-scale (2500 L) orbitally shaken bioreactors

Florian Maria Wurm, David Hacker

In this study, the combination of dimensional analysis (DA) and analysis of variance (ANOVA) was used to predict the volumetric mass transfer coefficient (k(L)a) values under different operating conditions for orbitally shaken bioreactors (OSRs) with diffe ...

SPRINGER HEIDELBERG2020

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

Florian Maria Wurm, David Hacker

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

Hyperosmolarity enhances transient recombinant protein yield in Chinese hamster ovary cells

Florian Maria Wurm, David Hacker, Lucia Baldi Unser

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

Novel orbital shake bioreactors for transient production of CHO derived IgGs

Florian Maria Wurm, David Hacker, Mathieu Benjamin Stettler

Large-scale transient gene expression in mammalian cells is being developed for the rapid production of recombinant proteins for biochemical and preclinical studies. Here, the scalability of transient production of a recombinant human antibody in Chinese h ...

American Chemical Society2007

A simple plasmid-based transient gene expression method using High Five cells

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

The High Five (H5) cell line, derived from the lepidopteran Trichoplusia ni, is one of the major insect cell hosts for the production of recombinant proteins using the baculovirus expression vector system (BEVS). Here, we describe a simple polyethylenimine ...

Elsevier2015

Recombinant protein production from stable mammalian cell lines and pools

David Hacker, Sowmya Balasubramanian

We highlight recent developments for the production of recombinant proteins from suspension-adapted mammalian cell lines. We discuss the generation of stable cell lines using transposons and lentivirus vectors (non-targeted transgene integration) and site- ...

Elsevier2016

Calcium phosphate transfection generates mammalian recombinant cell lines with higher specific productivity than polyfection

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

Transfection with polyethylenimine (PEI) was evaluated as a method for the generation of recombinant Chinese hamster ovary (CHO DG44) cell lines by direct comparison with calcium phosphate-DNA coprecipitation (CaPO4) using both green fluorescent protein (G ...

2008

Numerical simulation of orbitally shaken viscous fluids with free surface

Alfio Quarteroni, Florian Maria Wurm, David Hacker, Marco Discacciati, Samuel Quinodoz

Orbitally shaken bioreactors are an emerging alternative to stirred-tank bioreactors for large-scale mammalian cell culture, but their fluid dynamics is still not well defined. Among the theoretical and practical issues that remain to be resolved, the char ...

Wiley-Blackwell2013

Efficient and reproducible mammalian cell bioprocesses without probes and controllers?

Florian Maria Wurm, Mohamed Farhat, David Hacker, Lucia Baldi Unser, Matthieu Dreyer, Martino Reclari

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