Thermoresponsive Microgel Coatings as Versatile Functional Compounds for Novel Cell Manipulation Tools

Uhlig K, Wegener T, Hertle Y, et al. Thermoresponsive Microgel Coatings as Versatile Functional Compounds for Novel Cell Manipulation Tools. POLYMERS. 2018;10(6): 656.For the effective use of live cells in biomedicine as in vitro test systems or in biotechnology, non-invasive cell processing and characterisation are key elements. Thermoresponsive polymer coatings have been demonstrated to be highly beneficial for controlling the interaction of adherent cells through their cultivation support. However, the widespread application of these coatings is hampered by limitations in their adaptability to different cell types and because the full range of applications has not yet been fully explored. In the work presented here, we address these issues by focusing on three different aspects. With regard to the first aspect, by using well-defined laminar flow in a microchannel, a highly controllable and reproducible shear force can be applied to adherent cells. Employing this tool, we demonstrate that cells can be non-invasively detached from a support using a defined shear flow. The second aspect relates to the recent development of simple methods for patterning thermoresponsive coatings. Here, we show how such patterned coatings can be used for improving the handling and reliability of a wound-healing assay. Two pattern geometries are tested using mouse fibroblasts and CHO cells. In terms of the third aspect, the adhesiveness of cells depends on the cell type. Standard thermoresponsive coatings are not functional for all types of cells. By coadsorbing charged nanoparticles and thermoresponsive microgels, it is demonstrated that the adhesion and detachment behaviour of cells on such coatings can be modulated

Mobility of lysozyme in poly(L-lysine)/hyaluronic acid multilayer films

The spatial and temporal control over presentation of protein-based biomolecules such as growth factors and hormones is crucial for in vitro applications to mimic the complex in vivo environment. We investigated the interaction of a model protein lysozyme (Lys) with poly(L-lysine)/hyaluronic acid (PLL/HA) multilayer films. We focused on Lys diffusion as well as adsorption and retention within the film as a function of the film deposition conditions and post-treatment. Additionally, an effect of Lys concentration on its mobility was probed. A combination of confocal fluorescence microscopy, fluorescence recovery after photobleaching, and microfluidics was employed for this investigation. Our main finding is that adsorption of PLL and HA after protein loading induces acceleration and reduction of Lys mobility, respectively. These results suggest that a charge balance in the film to a high extent governs the protein–film interaction. We believe that control over protein mobility is a key to reach the full potential of the PLL/HA films as reservoirs for biomolecules depending on the application demand

The efficacy and effect on gut microbiota of an aflatoxin binder and a fumonisin esterase using an in vitro simulator of the human intestinal microbial ecosystem (SHIME®)

MycoSafe-Sout

Challenges in QCD matter physics - The Compressed Baryonic Matter experiment at FAIR

Substantial experimental and theoretical efforts worldwide are devoted to explore the phase diagram of strongly interacting matter. At LHC and top RHIC energies, QCD matter is studied at very high temperatures and nearly vanishing net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was created at experiments at RHIC and LHC. The transition from the QGP back to the hadron gas is found to be a smooth cross over. For larger net-baryon densities and lower temperatures, it is expected that the QCD phase diagram exhibits a rich structure, such as a first-order phase transition between hadronic and partonic matter which terminates in a critical point, or exotic phases like quarkyonic matter. The discovery of these landmarks would be a breakthrough in our understanding of the strong interaction and is therefore in the focus of various high-energy heavy-ion research programs. The Compressed Baryonic Matter (CBM) experiment at FAIR will play a unique role in the exploration of the QCD phase diagram in the region of high net-baryon densities, because it is designed to run at unprecedented interaction rates. High-rate operation is the key prerequisite for high-precision measurements of multi-differential observables and of rare diagnostic probes which are sensitive to the dense phase of the nuclear fireball. The goal of the CBM experiment at SIS100 (sqrt(s_NN) = 2.7 - 4.9 GeV) is to discover fundamental properties of QCD matter: the phase structure at large baryon-chemical potentials (mu_B > 500 MeV), effects of chiral symmetry, and the equation-of-state at high density as it is expected to occur in the core of neutron stars. In this article, we review the motivation for and the physics programme of CBM, including activities before the start of data taking in 2022, in the context of the worldwide efforts to explore high-density QCD matter.Comment: 15 pages, 11 figures. Published in European Physical Journal

Éthique et poésie lyrique (la langue, lieu de révélation du monde, dans les courants symboliste français et moderniste canadien)

S inscrivant dans le tournant éthique survenu il y a peu en théorie littéraire, cette étude analyse la relation entre éthique et poésie moderne, avançant que les implications éthiques de ces textes ne sont pas seulement enrichies par, mais aussiindissociables de l emploi créatif et non-conventionnel de la langue rencontré dans ce courant. La majorité des articles consacrés à la critique éthique se concentrent sur la transmission explicite de valeurs morales par le biais de romansou de nouvelles sans tenir compte de la complexité linguistique renfermée par l énoncé lyrique ou assimilent l éthique de la littérature, de façon très généralisée, à des phénomènes purement esthétiques à l instar de l expérience textuelleémanant de l altérité ou de l indécidabilité et contournent de ce fait les préoccupations éthiques concrètes de chacun des textes. Dans le but d atteindre une compréhension plus nuancée de la relation entre éthique et poésie (moderne), je propose d envisager la parole lyrique comme un lieu de révélation du monde ouvrant de nouvelles perspectives sur les questions éthiques qui restent voilées ou dissimulées dans le discours ordinaire. Cette idée a été développée par MartinHeidegger et Paul Ricoeur, qui, dans leurs écrits sur l art et la littérature, se penchent sur la manière dont les textes poétiques rompent avec les contraintes du discours institutionnel et rendent au langage son pouvoir expressif originel. [etc.]Situated in the context of the recent ethical turn in literary theory, this study examines the relationship between ethics and modernist poetry, arguing that the ethical implications of these texts are not only enriched by, but also inseparable from, the creative, unconventional use of language typical of this genre. The majority of studies in the field of ethical criticism either focus on the explicit transmission of moral values in novels and short stories, while ignoring the linguistic complexity at the heart of lyric utterance, or equate the ethics of literature, in a very generalized way, with purely aesthetic phenomena such asthe textual experience of alterity or undecidability, thereby bypassing the concrete ethical concerns of individual texts. In order to attain a more nuanced comprehension of the relationship between ethics and (modernist) poetry, I propose to view lyric language as a site of world-disclosure opening up new perspectives on ethical issues that remain veiled or hidden in ordinary speech. This idea has been elaborated by Martin Heidegger and Paul Ricoeur, whose writings on art and literature engage with the ways in which poetic texts break the constraints of institutionalized discourse and return language to its original, expressive power. [etc.]MONTPELLIER-BU Lettres (341722103) / SudocSudocFranceF

Control of cell adhesion by mechanical reinforcement of soft polyelectrolyte films with nanoparticles

Chemical cross-linking is the standard approach to tune the mechanical properties of polymer coatings for cell culture applications. Here we show that the elastic modulus of highly swollen polyelectrolyte films composed of poly(L-lysine) (PLL) and hyaluronic acid (HA) can be changed by more than 1 order of magnitude by addition of gold nanoparticles (AuNPs) in a one-step procedure. This hydrogel-nanoparticle architecture has great potential as a platform for advanced cell engineering application, for example remote release of drugs. As a first step toward utilization of such films for biomedical applications we identify the most favorable polymer/nanoparticle composition for optimized cell adhesion on the films. Using atomic force microscopy (AFM) we determine the following surface parameters that are relevant for cell adhesion, i.e., stiffness, roughness, and protein interactions. Optimized cell adhesion is observed for films with an elastic modulus of about 1 MPa and a surface roughness on the order of 30 nm. The analysis further shows that AuNPs are not incorporated in the HA/PLL bulk but form clusters on the film surface. Combined studies of the elastic modulus and surface topography indicate a cluster percolation threshold at a critical surface coverage above which the film stiffness drastically increases. In this context we also discuss changes in film thickness, material density and swelling ratio due to nanoparticle treatment