Joachim Wiest

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The recent advent of microphysiological systems - microfluidic biomimetic devices that aspire to emulate the biology of human tissues, organs and circulation in vitro - is envisaged to enable a global paradigm shift in drug development. An extraordinary US governmental initiative and various dedicated research programs in Europe and Asia have led recently(More)
Cells are organic microsystems with functional compartments interconnected by complex signal chains. Intracellular signaling routes and signal reception from the extracellular environment are characterized by redundancy, i.e., parallel pathways exist. If a cell is exposed to an external "signal input", the signal processing elements within the cell provide(More)
The Intelligent Mobile Lab (IMOLA) delivers metabolic and morphological parameters of living cells in a label-free and real time way. It represents a key technology for the development of new cell-based assays. Electrochemical microsensors are used to measure the extracellular acidification (pH), cellular respiration (pO2), changes in cell number and(More)
Frequency variation in spatial frequency domain imaging is a powerful tool for adjusting the penetration depth of the imaging signal and the parameter sensitivity toward absorption and diffusive and subdiffusive scattering. Through our computational analysis, using an analytical solution of the radiative transfer equation, we add quantitation to this tool(More)
Screening a newly developed drug, food additive or cosmetic ingredient for toxicity is a critical preliminary step before it can move forward in the development pipeline. Due to the sometimes dire consequences when a harmful agent is overlooked, toxicologists work under strict guidelines to effectively catalogue and classify new chemical agents.(More)
GOAL This contribution points out the need for well-defined and documented data processing protocols in microphysiometry, an evolving field of label-free cell assays. The sensitivity of the obtained cell metabolic rates toward different routines of raw data processing is evaluated. METHODS A standard microphysiometric experiment structured in discrete(More)
The supplementation of culture medium with fetal bovine serum (FBS, also referred to as 'fetal calf serum') is still common practice in cell culture applications. Due to a number of disadvantages in terms of quality and reproducibility of in vitro data, animal welfare concerns, and in light of recent cases of fraudulent marketing, the search for(More)
Tests for cytotoxicity–respectively biocompatibility–are performed e. g. for biological evaluation of medical devices or during the development of microphysiometric systems. Here, often cell culture methods which involve the use of fetal bovine serum (FBS) are employed. However, using FBS raises scientific and ethical concerns. In the presented work a(More)
Understanding the effect of exogenous substances on human skin is critical for toxicology assessment. To address this, numerous artificial models of the topmost layer of human skin, so-called reconstructed human epidermis (RhE), have been created in an attempt to produce a clear analogue for testing. Unfortunately, current testing modalities still rely on(More)
Jan van der Valk, Karen Bieback, Christiane Buta, Brett Cochrane Wilhelm G. Dirks, Jianan Fu, James J. Hickman, Christiane Hohensee, Roman Kolar, Manfred Liebsch, Francesca Pistollato, Markus Schulz, Daniel Thieme, Tilo Weber, Joachim Wiest, Stefan Winkler and Gerhard Gstraunthaler The 3Rs-Centre Utrecht Life Sciences, Utrecht University, Utrecht, The(More)