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David Hacker

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Related publications (83)

Transcriptional and post-transcriptional limitations of high-yielding, PEI-mediated transient transfection with CHO and HEK-293E cells

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

Transient gene expression (TGE) in human embryonic kidney (HEK-293) and Chinese hamster ovary (CHO) cells is a well-established technology for the rapid generation of recombinant proteins. Although the maximum TGE yields have reached 1 g/L or more, the amo ...

American Chemical Society2015

Production of active glycosylation-deficient gamma-secretase complex for crystallization studies

Florian Maria Wurm, David Hacker, Patrick Fraering, Mitko Dimitrov, Andres Ricardo Lopez Robles, Hermeto Gerber, Virginie Sandra Braman

Alzheimer's disease (AD)-associated gamma-secretase is a ubiquitously expressed multi-subunit protease complex embedded in the lipid bilayer of cellular compartments including endosomes and the plasma membrane. Although gamma-secretase is of crucial intere ...

Wiley-Blackwell2015

Virus-free transient protein production in Sf9 cells

Florian Maria Wurm, Lucia Baldi Unser, David Hacker, 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

Highly efficient production of the Alzheimer's γ-Secretase integral membrane protease complex by a multi-gene stable integration approach

Florian Maria Wurm, David Hacker, Patrick Fraering, Lorène Aeschbach, Mitko Dimitrov, Sowmya Balasubramanian

Inefficient production of membrane-embedded multi-protein complexes by conventional methods has largely prevented the generation of high-resolution structural information and the performance of high-throughput drug discovery screens for this class of prote ...

2013

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

David Hacker, Gilles Udin, Julien Bryois, Nouria Hernandez, Bart Deplancke, Alisa Yurovsky, Sunil Kumar Raghav, Sarah Thurnheer, Sebastian Martin Waszak

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

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

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

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

Helical-Track Bioreactors for Bacterial, Mammalian and Insect Cell Cultures

Florian Maria Wurm, Lucia Baldi Unser, David Hacker, Stéphanie Tissot, Clara Joséphine Douet

We investigated the cultivation of bacterial, mammalian and insect cells in an orbitally-shaken 250-mL disposable tube that incorporates a helical track (HT) on its inside wall. The mass transfer coefﬁcient of oxygen (kLa) was 200%–400% higher in the HT tu ...

2013

Numerical simulation of orbitally shaken viscous fluids with free surface

Florian Maria Wurm, Alfio Quarteroni, Marco Discacciati, David Hacker, Stéphanie Tissot, 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

Study of the improved Sf9 transient gene expression process

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

Insect cells have been widely used for the production of recombinant proteins using recombinant baculovirus for gene delivery [1]. To simplify protein production in insect cells, we have previously described a method, based on transient gene expression (TG ...

2013

Polyethyleneimine-based transient gene expression processes for suspension-adapted HEK-293E and CHO-DG44 cells

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

Transient gene expression (TGE) from mammalian cells is an increasingly important tool for the rapid production of recombinant proteins for research applications in biochemistry, structural biology, and biomedicine. Here we review methods for the transfect ...

Elsevier2013

The optimization of a rapid low-cost alternative of large-scale medium sterilization

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

2013

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

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

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

Hyperbranched Polylysine: A Versatile, Biodegradable Transfection Agent for the Production of Recombinant Proteins by Transient Gene Expression and the Transfection of Primary Cells

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

The feasibility of a new transfection agent, HBPL, for the production of recombinant IgG antibody via TGE as well as for the transfection of primary cells is studied. Under the conditions investigated, transfection of CHO-DG44 cells using HBPL results in I ...

2012

Comparative Study on the In Vitro Cytotoxicity of Linear, Dendritic, and Hyperbranched Polylysine Analogues

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

Lysine-based polycations are widely used as nonviral carriers for gene delivery. This manuscript reports the results of a comparative study on the in vitro cytotoxicity of a library of three structural polylysine variants, namely, linear polylysine (LPL), ...

American Chemical Society2012

A NanoDrop-based method for rapid determination of viability decline in suspension cultures of animal cells

Florian Maria Wurm, Lucia Baldi Unser, David Hacker, Mélanie Hubert

We describe a rapid method for monitoring the cell growth and decline phases in suspension cultures of animal cells. During the cell growth phase, ultraviolet (UV)-absorbing components in the medium are consumed, but at later times as cells begin to die, U ...

Elsevier2012

Role of non-specific DNA in reducing coding DNA requirement for transient gene expression with CHO and HEK-293E cells

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

Transient gene expression (TGE) is a rapid method for the production of recombinant proteins in mammalian cells. While the TGE volumetric productivity has improved significantly over the past decade, the amount of plasmid DNA (pDNA) needed for transfection ...

2012

k(L)a as a predictor for successful probe-independent mammalian cell bioprocesses in orbitally shaken bioreactors

Florian Maria Wurm, Lucia Baldi Unser, David Hacker, Stéphanie Tissot

The aim of this study was to gain a better understanding of orbitally shaken bioreactors (OSRs) operated without controllers for pH and dissolved oxygen (DO) concentration. We used cylindrical OSRs with working volumes ranging from 250mL to 200L to determi ...

Elsevier2012

Poly(ethyleneimine)-Mediated Large-Scale Transient Gene Expression: Influence of Molecular Weight, Polydispersity and N-Propionyl Groups

Florian Maria Wurm, Lucia Baldi Unser, Sophie Nallet, David Hacker, Harm-Anton Klok, Zuzana Kadlecova

Three synthesis lots of linear poly(ethyleneimine) (PEI) are compared to a fully hydrolyzed linear PEI (commercially available as PEI Max) regarding structure, polyplex formation with plasmid DNA, and transfection of suspension-adapted HEK-293E cells. PEI ...

Wiley-Blackwell2012

Large-Scale Transfection of Mammalian Cells

Florian Maria Wurm, Lucia Baldi Unser, David Hacker, Carine Meerschman

The large-scale transfection of mammalian cells allows moderate (milligram to gram) amounts of recombinant proteins (r-proteins) to be obtained for fundamental or clinical research. In this article, we describe a one-liter transfection using polyethyleneim ...

Humana Press2011

Hydrodynamic stress in orbitally shaken bioreactors

Florian Maria Wurm, Lucia Baldi Unser, Alfio Quarteroni, Mohamed Farhat, Marco Discacciati, David Hacker, Stéphanie Tissot, Martino Reclari, Samuel Quinodoz, Matthieu Dreyer, Dominique Terry Monteil Jr

2011

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