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General Information

The BioInterface Seminars take place in seminar room Sem.R. DA grün 03B (Freihaus, green area, 3rd 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!



Announcements of the upcoming Seminars: go to Biointerface Seminar 2019/20



Schedule

Date of Seminar
External Speaker
Title of Seminar
Internal Speakers
2 PhD students per Seminar (20 min. each)
12.10.2018 Ronald Zirbs (BOKU)
inv. Stefan Baudis
Polypeptoids: Synthetic polymers with functional secondary structures applied in core-shell nanomaterials Stefan Helfert
Rafaela Conceicao
16.11.2018 Bruno Zappone (CNR-Nanotec, Rende, Italy)
inv. Philipp Thurner
Surface adhesion and lubrication in aqueous media mediated by secreted proteins Iris Dorner
Andreas Rohatschek
11.01.2019 Andreas Zöttl (TU Wien)
inv. Gerhard Kahl
Model bacteria swimming in polymer solutions Tobia Cavalli
Susanne Wagner
25.01.2019 Ralf Jungmann
(MPI Munich)
Super-resolution Microscopy with DNA Molecules: Towards Localizomics Agnes Dobos
Joschka Hellmeier
15.03.2019 Johannes Grillari
(BOKU Wien)
From cellular Senescence to Biomarkers of age-associated Diseases Clara Bodner
Valentina Wittner
12.04.2019 Peter Ertl
(TU Wien)
Next Generation Organ-on-a-Chip Systems Incorporating Biomechanical Cues Stefan Helfert
Rafaela Conceicao
17.05.2019 -
Progress reports Susanne Wagner
Andreas Rohatschek
28.06.2019 Emanuela Bianchi
(TU Wien)
Mosaics of patchy rhombi: from close-packed arrangements to open lattices Tobia Cavalli
Iris Dorner


Past Talks


(28.06.2019) Emanuela Bianchi: Mosaics of patchy rhombi: from close - packed arrangements to open lattices

Abstract: In the realm of functional materials, the production of two-dimensional structures with tunable porosity is of paramount relevance for many practical applications: surfaces with regular arrays of pores can be used for selective adsorption or immobilization of guest units that are complementary in shape and/or size to the pores, thus achieving, for instance, selective filtering or well - defined responses to external stimuli. This simple principle is valid at both the molecular and the colloidal length scale.

Here we provide simple design directions to combine the anisotropic shape of the building units – either molecules or colloids – and selective directional bonding [1]. Our model- hard rhombi with localized interactions sites - has been proven to mimic the steric and attractive interactions of tetracarboxylic acids, small rigid organic molecules with functional carboxylic groups [2,3].

We show that regular rhombic platelets decorated with attractive and repulsive interaction sites target specific tilings, going smoothly from close-packed arrangements to open lattices. The rationale behind the rich tiling scenario observed can be described in terms of steric incompatibilities, unsatisfied bonding geometries and interplays between local and long - range order.

We are confident that the design principles we found through exploring various tuning parameters will guide the way to building new interesting materials. In particular, the ability to fine tune the lattice porosity leads us to speculate about lattices that can dynamically and reversibly switch between close - packed and open structures. The colloidal junctions [4] might prove to be the experimental realization of these dynamically switchable tilings.

References:

[1] "Mosaics of patchy rhombi: from close- packed arrangements to open lattices", Carina Karner et al., to be submitted.

[2] "Random and ordered phases of off- lattice rhombus tiles", S. Whitelam et al., Phys Rev. Lett., 108, 035702 (2012)

[3] "Broken symmetry and the variation of critical properties in the phase behaviour of supramolecular rhombus tilings", Stannard et al.,Nat. Chem., 4, 112 (2012)

[4] "Colloidal joints with designed motion range and tunable joint flexibility", I. Chakraborty et al., Nanoscale, 9, 7814 (2017)


(12.04.2019) Next Generation Organ-on-a-Chip Systems Incorporating Biomechanical Cues

Abstract: Microfluidics is both the technology to fabricate microdevices and the science to study the behavior of fluids, (bio)chemical reactions and biological responses at the microscale. A new and promising research field which simultaneously addresses the fundamental need to develop alternative methods for animal tests is called organ-on- a-chip technology or tissue-tissue microarrays, where the recreation of near native and physiological-relevant culture conditions has shown to promote the formation of organotypic structures on a microchip platform. In light of the benefits of organ-on-a-chip technologies, my research group at TUW is developing lab-on-a-chip systems containing integrated fluid handling, degassing, mechanical actuators and biosensing systems to non-invasively monitor dynamic cell population responses. We have successfully integrated different electro-analytical, magnetic and optical detection methods in microfluidic devices to detect cell-to-cell and cell-to-matrix interactions. In course of the presentation advantages and disadvantages of various cell-based lab-on-a-chip systems capable of providing biomechanical forces will be discussed. Additionally a number of applications including cell migration assays, allergic responsens, shear force dependent nanoparticle uptake as well as the formation of pre-vascular networks and midbrain structures will be presented.

Peter Ertl holds an engineering degree in Biotechnology (BOKU, Austria), a PhD in Chemistry (Univ. Waterloo, Canada) and received his postdoctoral training as a biophysicist at University of California at Berkeley (US). Additionally, in 2003 Dr. Ertl co-founded a biotech start-up company where he served a number of years as Director of Product Development in Kitchener-Waterloo (CAD) developing benchtop-sized cell analyzers. In 2005 Dr. Ertl moved to Austria where he worked as Senior Scientist in the BioSensor Technology unit at the AIT Austrian Institute of Technology. In 2016 he was appointed Professor for Lab-on-a-Chip Systems for Bioscience Technologies at the Faculty of Technical Chemistry of the Vienna University of Technology. Dr. Ertl was also granted a Fulbright Visiting Scholarship at UC Berkeley in 2011/2012 and conducted visiting scientist positions at Nanyang Technological University, Singapore in 2013 and the Medical Center of the University of California at San Francisco in 2014. In 2016 Dr. Ertl was appointed Professor for Lab-on-a-Chip Systems in Bioscience Technologies where his research focuses on the development of organ-on-a-chip and chip-in-organ systems for biomedical research.



(15.03.2019) From cellular Senescence to Biomarkers of age-associated Diseases

Abstract: Cellular senescence has evolved from an in vitro model system to study aging to a multifaceted phenomenon of in vivo importance as senescent cell removal delays the onset of a variety of age-associated diseases and chemotherapy induced premature aging. In order to understand how senescent cells that accumulate within organisms with age negatively impact on organ and tissue function, we have characterized senescent cell derived extracellular vesicles (EVs) and their miRNA cargo and their functional role in the context of cellular and organismal aging. Thereby, we identified EVs and circulating miRNAs as bona fide members of the senescence associated secretory phenotype (SASP) that are transferred from senescent cells to their microenvironment or even the systemic environment. Upon uptake, recipient cells alter their behaviour, including changes in osteogenic differentiation of mesenchymal stem cells, in wound healing of skin keratinocytes, or apoptotic behaviour of skin fibroblasts. Especially in the context of osteogenic differentiation, we were further able to show that circulating miRNAs are prognostic biomarkers of osteoporotic fracture risk. In summary, we present evidence of the importance of specific miRNAs and highlight their potential use as biomarkers of aging and age-associated diseases, or even as therapeutic tools and targets to prevent ageassociated diseases.

Johannes Grillari’s research focus is on improving our understanding of the molecular and physiological changes that occur during cellular aging, their impact on organismal aging and regeneration, specifically in skin and bone. In addition, he is interested in engineering of mammalian cells to establish relevant and standardizable cell model systems and cell factories. Johannes Grillari has graduated in Biotechnology at the University of Natural Resources and Life Sciences Vienna (BOKU) in Austria, where he also accomplished his PhD in the field of cell aging in 1999. Since then he has founded and is leading the Christian Doppler Laboratory on Biotechnology of Skin Aging at the Department of Biotechnology at BOKU. He has worked as visiting scientist in the lab of Angus Lamond in Dundee, Scotland, for half a year in the field of RNA biology. In 2010 he was appointed Associate Professor at BOKU, in 2019 director of the Ludwig Boltzmann Institute of Experimental and Clinical Traumatology. He also acted as co-founder in 2011 for Evercyte, a company generating and providing immortalized cells for in vitro toxiciology, biopharmaceutical and cosmetical research and development, where he also acts as CSO. In 2013, he co-founded TAmiRNA, a company interested in identifying circulating miRNAs as biomarkers for aging and age-associated diseases, specifically in osteoporosis. He has published more than 130 peer reviewed articles, holds 13 patents and has been invited speaker to more than 120 international conferences and departmental seminars. He has received several awards including the Walter-Doberauer award for aging research.



(25.01.2019) Super-resolution Microscopy with DNA Molecules: Towards Localizomics

Abstract: Super-resolution fluorescence microscopy is a powerful tool for biological research. We use the transient binding of short fluorescently labeled oligonucleotides (DNA-PAINT) for easy-to-implement multiplexed super-resolution imaging that technically achieves sub-5-nm spatial resolution To translate this resolution to cellular imaging, we introduce Slow Off-rate Modified Aptamers (SOMAmers) as efficient and quantitative labeling reagents. We demonstrate the achievable image resolution and specificity by labeling and imaging of transmembrane as well as intracellular targets in fixed and live cell-specimen. Apart from ever increasing spatial resolution, efficient multiplexing strategies for the simultaneous detection of hundreds of molecular species are still elusive. We introduce a new approach to multiplexed super-resolution microscopy by designing the blinking behavior of targets with engineered binding frequency and duration. We assay this kinetic barcoding approach in silico and in vitro using DNA origami structures, show the applicability for multiplexed RNA and protein detection in cells and finally experimentally demonstrate 124-plex super-resolution imaging within minutes.

Ralf Jungmann received his Ph.D. degree in physics from the Technical University Munich in 2010. From 2011 to 2014, he was Postdoctoral Fellow at the Wyss Institute at Harvard University. Since 2015, Jungmann is heading an independent research group at the MPI of Biochemistry and the LMU Munich supported by the Emmy Noether Program of the German Research Foundation. In 2016, he received an ERC Starting grant and was appointed as Associate Professor at the LMU Munich.


(11.01.2019) Model bacteria swimming in polymer solutions

Abstract: Studying the locomotion of microorganisms has become a largely growing field (“active matter”) in physics in the last years. Due to the micron size their motion in Newtonian fluids (such as water) is dominated by viscous drag rather than inertia. In the absence of external forces non-reciprocal deformations of their cell body create fluid flow around them and enable them to move, they are therefore intrinsically out of equilibrium. Important examples of such motile “micro-swimmers” are sperm cells or bacteria with periodically beating appendages (“flagella”) at the back of their cell body. In the human body they swim through mucus which is a viscoelastic hydrogel mainly consisting of water and a crosslinked network of long (up to some micron) linear bio-polymers.

I will first introduce the basic physical mechanisms how bacteria can move force- and torque-free in simple Newtonian viscous fluids, and will then show that - contrary to intuition - bacteria can move faster in polymeric fluids compared to water, despite the fact that the viscosity in polymeric fluids is larger.

Andreas Zöttl received his PhD in 2014 from TU Berlin. After several stays abroad (University of Oxford, ESPCI) as PostDoc he returned to TU Wien and is employed as a PostDoc within Gerhard Kahls group since the beginning of this year.


(16.11.2018) Surface adhesion and lubrication in aqueous media mediated by secreted proteins

Abstract: Recent insights into the fundamental molecular-scale mechanisms of protein-based adhesion and lubrication are fueling the development of novel biomimetic materials, particularly for medical and bioengineering applications. Mussels show an extraordinary ability to adhere rapidly and firmly to virtually any submerged surface, notably wave-swept rocks and anti-adhesive coatings used to protect ship hulls. DOPA has been identified as the main surface adhesive and tissue cohesive agent through a series of studies on blue mussels. Yet DOPA functionalities are expressed within a complex network of molecular interactions that are not fully understood. Our work on the Asian green mussel Perna Viridis has shown that DOPA-mediated adhesion does not require a specific protein sequence but rather a regulated sequence of protein secretion whereby one DOPA-protein acts as ‘primer’ molecule, displacing surface-bound water molecules and establishing the ground for other proteins to build the mussel’s surface tether (byssus). This suggests that synergies among different DOPA-containing molecules should be considered in the development of biomedical polymer-based adhesives (e.g. for sutureless surgery, tissue repair and implant integration). In this context it is equally important to understand how living organisms remove adhesion and lubricate biological surfaces, which may guide the development of better lubricants, materials and devices for medicine (e.g. for endoscopes, catheters, contact lenses, cartilage implants, heart valves). Our studies on lubricin - the main lubricating agent of articular joints - bovine submaxillary mucin and porcine gastric mucin, all having a “bottle-brush” polymer-like structure, show that they lubricate the substrate by adsorbing as dense “brush-like” layers. However, again, a biomimetic approach to lubrication should take into account that mucins synergistically interact with other macromolecules, notably hyaluronic acid in articular joints.

Bruno Zappone received a joint PhD degree in condensed matter physics at the Université de Bordeaux I and University of Calabria in 2004. From 2004 to 2006 he worked at the University of California Santa Barbara in prof. J. Israelachvili’s group and later joined the Italian National Research Council (CNR). He also teaches soft matter physics at the University of Calabria. Bruno Zappone has pioneered mucin nanotribology with his work on lubricin (proteoglycan 4) using the Surface Force Apparatus (SFA). His current scientific interest are in the physics of complex fluids and soft/biological materials with focus on interfacial and nanoconfinement properties, particularly adhesion, nanomechanics (viscoelasticity) and nanotribology of mucins/mucus, mussel foot proteins and whole-tissue corneal epithelium. He is also expert in SFA multiple-beam optical interference and studies interfacial phenomena, defects and guided assembly of nanoparticle in liquid crystals.


(12.10.2018) Polypeptoids: Synthetic polymers with functional secondary structures applied in core-shell nanomaterials

Abstract: Bioinspired polymeric materials such as polypeptoids attract interest due to their ability to mimik or even surpass their natural counterparts (biopolymers) in certain properties. The chemical and physical properties of polypeptoids can not only be precisely controlled are precisely tuneable over a broad range but they also provide enhanced stability and improved processability compared to natural polymers. Evenmore polypeptoids combine the properties of biopolymers such as sequence specific functions (secondary and tertiary structures) with the properties of traditional synthetic polymers (robustness, synthetic pathway). Polypeptoids consist of N-substituted backbones and a variable sidechain which makes them highly vatiable. Especially the ability to form secondary structures is extremely promising – helical structures and sheets with precisely designable geometries represent a perfect foundation for innovative functional materials. The ability to predict, synthesize and exploit structures on a molecular level enables unrivaled and unique material properties (e.g. high grafting-density on nanoparticles, novel micellar structures, thermoresponsive behaviour). This work combines different synthetic strategies to generate polypeptoids with our pronounced expertice in nanoparticle synthesis and modification with the aim to develop responsive, superstable and functional nanomaterials for the use in material science and drug delivery.

Ronald Zirbs received his Ph.D. degree in Chemistry from the Technical University of Vienna in 2009. In 2010 he became Senior Scientist at the BOKU, Austria. He is working towards a habilitation in the area of synthesis of hybrid smart materials.