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David Hacker

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Related publications (82)

Page 3 of 5

Studies on fluid dynamics of the flow field and gas transfer in orbitally shaken tubes

Florian Maria Wurm, David Hacker, Xiao Shen, Dominique Terry Monteil Jr

Orbitally shaken cylindrical bioreactors [OrbShake bioreactors (OSRs)] without an impeller or sparger are increasingly being used for the suspension cultivation of mammalian cells. Among small volume OSRs, 50-mL tubes with a ventilated cap (OSR50), origina ...

American Chemical Society2017

Expression proteomics study to determine metallodrug targets and optimal drug combinations

Paul Joseph Dyson, Kai Johnsson, David Hacker, Claire Samantha Allardyce

The emerging technique termed functional identification of target by expression proteomics (FITExP) has been shown to identify the key protein targets of anti-cancer drugs. Here, we use this approach to elucidate the proteins involved in the mechanism of a ...

Nature Research2017

Chromatin three-dimensional interactions mediate genetic effects on gene expression

David Hacker, Philipp Bucher, Giovanna Ambrosini, Aurélien Dominique Reymond

Studying the genetic basis of gene expression and chromatin organization is key to characterizing the effect of genetic variability on the function and structure of the human genome. Here we unravel how genetic variation perturbs gene regulation using a da ...

American Association for the Advancement of Science2019

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

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

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

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

Florian Maria Wurm, David Hacker, Lucia Baldi Unser

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

Orbital shaker technology for the cultivation of mammalian cells in suspension

Florian Maria Wurm, David Hacker, Martin Jordan, Philippe Pierre Girard, Natalie Muller

For large-scale applications in biotechnology, cultivation of mammalian cells in suspension is an essential prerequisite. Typically, suspension cultures are grown in glass spinner flasks filled to less than 50% of the nominal volume. We propose a superior ...

2005

Recombinant protein production by large-scale transient gene expression in mammalian cells : state of the art and future perspectives

Florian Maria Wurm, David Hacker, Lucia Baldi Unser

The expansion of the biologics pipeline depends on the identification of candidate proteins for clinical trials. Speed is one of the critical issues, and the rapid production of high quality, research-grade material for preclinical studies by transient gen ...

Kluwer Academic Publishers, Springer2007

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

Florian Maria Wurm, David Hacker, Lucia Baldi Unser

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

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

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

Study of the improved Sf9 transient gene expression process

Florian Maria Wurm, David Hacker, Lucia Baldi Unser, 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

Polyethylenimine-based quality control assay for plasmid DNA

Florian Maria Wurm, David Hacker, Martin Jordan, Martin Bertschinger, Gaurav Backliwal

2006

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

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

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

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

Florian Maria Wurm, David Hacker, Lucia Baldi Unser

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

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

Florian Maria Wurm, David Hacker, Lucia Baldi Unser, 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

Respiratory syncytial virus subunit vaccine based on a recombinant fusion protein expressed transiently in mammalian cells

Florian Maria Wurm, David Hacker, Lucia Baldi Unser

Although respiratory syncytial virus (RSV) causes severe lower respiratory tract infection in infants and adults at risk, no RSV vaccine is currently available. In this report, efforts toward the generation of an RSV subunit vaccine using recombinant RSV f ...

2009

Structural investigation of ACE2 dependent disassembly of the trimeric SARS-CoV-2 Spike glycoprotein

Henning Paul-Julius Stahlberg, David Hacker, Florence Pojer, Dongchun Ni, Kelvin Ka Ching Lau

The human membrane protein Angiotensin-converting enzyme 2 (hACE2) acts as the main receptor for host cells invasion of the new coronavirus SARS-CoV-2. The viral surface glycoprotein Spike binds to hACE2, which triggers virus entry into cells. As of today, ...

2020

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

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

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

Disposable orbitally shaken TubeSpin bioreactor 600 for Sf9 cell cultivation in suspension

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

Disposable orbitally shaken TubeSpin bioreactor 600 tubes (TS600s) were recently developed for the bench-scale cultivation of animal cells in suspension. Here we compared batch cultures of Sf9 insect cells in TS600s, spinner flasks, and shake flasks. Super ...

Elsevier2016

The kinetics of polyethylenimine-mediated transfection in suspension cultures of Chinese hamster ovary cells

Florian Maria Wurm, David Hacker, Martin Bertschinger

The kinetics of polyethylenimine (PEI)-mediated gene transfer at early times after transfection of Chinese hamster ovary (CHO) cell in suspension were investigated using a novel in vitro assay. Addition of an excess of competitor DNA to the culture medium ...

Humana Press Inc, Springer2008

A comparison of orbitally-shaken and stirred-tank bioreactors: pH modulation and bioreactor type affect CHO cell growth and protein glycosylation

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

Orbitally shaken bioreactors (OSRs) support the suspension cultivation of animal cells at volumetric scales up to 200 L and are a potential alternative to stirred-tank bioreactors (STRs) due to their rapid and homogeneous mixing and high oxygen transfer ra ...

American Chemical Society2016