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General Information

The BioInterface Seminars take place in seminar room Sem.R. DA grün 03B (Freihaus, green area, 3th floor) on friday afternoons (13:00-16:00). This semester, the seminar will start with the students' talks followed by a talk given by the invited speaker. We intend to create an open space for discussions and exchange of experiences. Feel free to join- there will be snacks and drinks!


Upcoming Talks

(06.03.2020) Thorsten Hugel: "Nanomechanical properties of early osteoarthritic cartilage: combining AFM and fluorescence based methods"

Abstract: Osteoarthritis (OA) is the most common degenerative joint disorder. Its underlying mechanisms remain elusive and the available treatment is symptomatic. Spatially resolved monitoring of articular cartilage (AC) might enhance our ability to specifically detect the early stages of OA for improving our understanding of disease and fostering effective therapies. Using atomic force microscopy and fluorescence microscopy, we correlate local human AC superficial zone surface stiffness (contact mechanics) with the cellular spatial organization, used as a marker for early OA-associated AC changes. We demonstrate that major loss of AC nanoscale surface stiffness is detectable in those AC samples that display the earliest identifiable OA, suggesting that loss of AC surface stiffness in human OA occurs much earlier than anticipated [1]. We then demonstrate successful identification of the cellular spatial organization of AC with a commercially available, clinically usable probe-based confocal laser-endomicroscope [1]. Finally, we show first AFM-based results on changes in the organization of the collagen network of human AC by early OA.

References:

[1] M. Tschaikowsky et al., bioRxiv (2018); www.biorxiv.org/content/10.1101/734368v1


Schedule

Date of Seminar
External Speaker
Title of Seminar
Internal Speakers
2 PhD students per Seminar (20 min. each)
11.10.2019 Heinrich Krobath
(JKU Linz)
Thermal membrane undulations affect equilibrium binding and domain stability of membrane proteins in adhesion zones Joschka Hellmeier
Agnes Dobos
08.11.2019 Stefan Scheiner
(TU Wien)
Bone remodeling studied by means of a coupled systems biology and multiscale bone mechanobiology approach Iris Dorner
Valentina Wittner
06.12.2019 Brigitte Holzer
(TU Wien)
Tailoring Surface Properties in Organic Bioelectronics Stefan Helfert
Raffaela Conceicao
06.03.2020 Thorsten Hugel
(Albert-Ludwigs-Universität Freiburg)
Nanomechanical properties of early osteoarthritic cartilage: combining AFM and fluorescence based methods Andreas Rohatschek
Clara Bodner
24.04.2020 Primoz Ziherl
(J. Stefan Institut, Ljubljana)
TBA Susanne Wagner
Tobia Cavalli


Past Talks

(06.12.2019) Brigitte Holzer: Tailoring Surface Properties in Organic Bioelectronics

Abstract: In the last decade, organic bioelectronic devices have emerged as a promising platform merging the fields of biology and organic electronics. This highly interdisciplinary research area allows the fabrication of low‐cost, flexible, and solution-processable devices suitable for operation in biological electrolytes. Especially, the chemical design of the interface between biological moieties and a transducer allows tailoring surface properties of biosensors. Within this presentation, the functionalization of gold surfaces applicable as electrodes in electrolyte gated field effect transistors will be discussed.[1,2] These devices are potential tools for label-free diagnostics offering point-of-care detection of biologically relevant markers. Furthermore, new approaches toward surface functionalization will be introduced allowing the fabrication of stable biosensors as well as translating biological events into electronic or optical signals.

References:

[1] Holzer et. al, Advanced Biosystems 2017, 1700055

[2] Macchia et. al, Nature Communications 2018, 9 (1), 3223


(08.11.2019) Stefan Scheiner: Bone remodeling studied by means of a coupled systems biology and multiscale bone mechanobiology approach

(11.10.2019) Heinrich Krobath: Thermal membrane undulations affect equilibrium binding and domain stability of membrane proteins in adhesion zones

Abstract: Membrane protein binding and unbinding processes stand out as a reliable means of intercellular adhesion-based signal transduction. Based Helfrich’s elastic membrane model [1], we attempt to shed light on the subtle effects of thermal membrane undulations on equilibrium binding and domain formation of membrane-anchored proteins maintaining a cellular adhesion zone. Devising a statistical mechanics approach supported by Monte-Carlo (MC) simulations [2], we find that successful receptor-ligand binding locally encourages the establishment of proximal bound complexes. This mechanistic picture entails a local cooperative law of mass action for receptor-ligand interactions in membrane adhesion zones [3]. On the other hand, we present an extension of this adhesion model reminiscent of the immunological synapse containing two pairs of receptors and ligands – e.g. pMHC-TCR and LFA/ICAM – differing in size and binding affinity. In such a setting, stable domain formation is possible. We corroborate the existence of a critical point [4] of domain formation caused by membrane shape fluctuations and use classical nucleation theory to derive stability criteria for co-existing micro-domains. In this context, we show that membrane undulations increase the energetic penalty for domain formation by modulating line tension scaling near the critical point [5]. These thermally stable micro-domains may merge to macroscopic domains conducive to immunological synapse formation.

References:

[1] TR Weikl, M Asfaw, H Krobath, et al. Soft Matter, 2009, 5(17):3213-3224.

[2] H Krobath, GJ Schütz, R Lipowsky, TR Weikl. Europhys Lett., 2007, 78:38003

[3] H Krobath, B Różycki, R Lipowsky, TR Weikl. Soft Matter, 2009, 5:3354-3361.

[4] M Asfaw, B Różycki, R Lipowsky, TR Weikl. Europhys Lett., 2006, 76(4):703-709.

[5] H Krobath, B Różycki, R Lipowsky, TR Weikl. PLoS ONE, 2011, 6(8): e23284.