COST Action TD0906
nd 2 scientific meeting
Biological and Biomimetic
Adhesives
Mons, Belgium 18-20 May 2011
www.cost-bioadhesives.org
Biological and Biomimetic Adhesives Mons, 18-20 May 2011
Programme overview
Wednesday May 18 th
Oral sessions and Management Committee meeting will be held in the Gutenberg auditorium. Coffee breaks, lunch, and poster session will take place in the Plisnier Hall.
08:00 - 09:15 Registration
09:15 - 09:30 Welcome talks
09:30 - 10:30 Oral communications (Chairman: Markus Linder)
9:30 Janek von Byern “Gluing to survive-Antipredator strategy of salamanders”
9:50 Mustafa O. Guler “Dopa functionalized peptide nanofibers for metal implant surface bioactivation”
10:10 Peter Ladurner “Macrostomum lignano as a model system to study duo-gland adhesive organs of flatworms”
10:30 – 11:00 Coffee break
11:00 – 12:00 Oral communications (Chairwoman: Marisa Almeida)
11:00 Peter Kasak “Zwitterionic polymer as tool against biofouling”
11:20 Markus Linder “Biological adhesives as building blocks in nanomaterials”
11:40 Jon Barnes “Wet but non slippery: bioinspired adhesives that work in humid and flooded conditions
12:00 – 13:30 Lunch
13:30 – 15:00 COST Management Committee meeting (Everybody can join but only the Management Committee is allowed to vote)
15:00 – 15:30 Coffee break
15:30 – 17:30 Poster session
Thursday May 19 th
Oral sessions and Management Committee meeting will be held in the Curie auditorium. Coffee breaks, lunch, and poster session will take place in the Plisnier Hall.
09:30 - 10:30 Oral communications (Chairman: Janek von Byern)
9:30 Bjoern Melzer “The climbing roots of Vanilla spec. –first insights into the attachment system of a monocot”
9:50 Havazelet Bianco-Peled “Small Angle X-ray Scattering for the study of biological adhesives”
10:10 Niall Crawford “The self-cleaning properties of the toe pads of tree frogs”
10:30 – 11:00 Coffee break
11:00 – 12:00 Oral communications (Chairman: Philippe Leclère)
11:00 Vanessa Zheden “ Dosima fascicularis : a barnacle, which floats rather than sticks”
11:20 Dagmar Voigt “Study of biological adhesives using cryo-scanning electron microscopy”
11:40 Luigi Petrone “Settlement assays of Balanus amphitrite cyprids”
12:00 – 13:30 Lunch
13:30 – 15:30 Working Group discussions
15:30 – 16:00 Coffee break
16:00 – 17:20 Oral communications (Chairwoman: Aránzazu del Campo)
16:00 Meir Haber “ In-vitro adhesion assay - Skin surface model”
16:20 Tina Steinbrecher “Permanent attachment pads of Parthenocissus spec. –morphology and biomechanics”
16:40 Gabriel Furtos “Mechanical properties of dual curing bone cement based on glass fibers”
17:00 Padraig Keane “Asymmetric spatula heads combined with lateral forces provide a mechanism for controlling the adhesive attachment of a range of spider species”
18:30 Banquet (Mundaneum)
Friday May 20 th
Oral sessions and Management Committee meeting will be held in the Curie auditorium. Coffee breaks, lunch, and poster session will take place in the Plisnier Hall.
09:30 - 10:30 Oral communications (Chairwoman: Dagmar Voigt)
9:30 Klaus Rischka “Adsorption properties of mussel based peptide sequences”
9:50 Ebru Toksoy Oner “Thin nanostructured bioactive films by MAPLE assembling”
10:10 Michael Röhrig “Fabrication of hierarchical Gecko-mimicking structures”
10:30 – 11:00 Coffee break 11:00 – 12:30 Oral communications (Chairman: Willi Schwotzer) 11:00 Sven Bundschuh “Stress analysis and parameter study of permanent attachment pads of Parthenocissus tricuspidata by Finite Element simulations”
11:20 João F. Mano “Development of new multilayer films based on chitosan and dopamine-modified hyaluronic acid”
11:40 Marleen Kamperman “Design, synthesis and characterization of artificial bioinspired adhesives”
12:30 – 14:00 Lunch
14:00 – 15:00 Working Group discussions
15:00 Goodbye coffee
Draft Agenda Management Committee Meeting
COST Action TD0906 Biological Adhesives: from Biology to Biomimetics Mons, Belgium, the 18 th May 2011
1. Adoption of agenda 2. Minutes of last meeting 3. Matters arising 4. Report from the COST Office − News from the COST Office − Status of Action, including participating countries − Budget status, budget planning and allocation process 5. Progress report of working groups 6. Action planning 6.1 Annual Progress Conference (preparation and/or feedback from DC) 6.2 Action Budget Planning 6.3 Action Planning (including meetings) 6.3.1 Location and date of next meeting 6.3.2 Long-term planning (including anticipated locations and dates of future meetings) 7. STSM status, applications 8. Publications, dissemination and outreach activities 9. Request for new members 10. Promotion of gender balance and of Early Stage Researchers (ESR) 11. Non-COST country participations 12. Web news 13. AOB 14. Closing
Participant list
Surname First Name Organisation Country Email address
ALBERT Klaus University of Tübingen Germany [email protected] ALMEIDA Marise University of Lisbon Portugal [email protected] ATHANASSIADOU Eleftheria CHIMAR HELLAS SA Greece [email protected] BARNES Jon University of Glasgow United Kingdom [email protected] BECKER Pierre University of Mons Belgium [email protected] BELS Vincent Muséum National d'Histoire Naturelle, Paris France [email protected] BERNARDI Antonietta University of Naples Italy [email protected] BERNARDINI Cecilia Wageningen University The Netherlands [email protected] BIANCO-PELED Havazelet Technion Israel [email protected] BOONAERT Christophe AGC Belgium [email protected] BRAUN Julius University of Tübingen Germany [email protected] BUNDSCHUH Sven Karlsruhe Institute of Technology (KIT) Germany [email protected] CAULIER Guillaume University of Mons Belgium [email protected] CRAWFORD Niall University of Glasgow United Kingdom [email protected] CYRAN Norbert University of Vienna Austria [email protected] DEL CAMPO Aránzazu Max-Planck-Institut for Polymer Research Germany [email protected] DELESTRÉE Mathilde AGC Belgium [email protected] DELROISSE Jérôme University of Mons Belgium [email protected] DEMEULDRE Mélanie University of Mons Belgium [email protected] EBERL Christoph Karlsruhe Institute of Technology (KIT) Germany [email protected] EDERTH Thomas Linköping University Sweden [email protected] ELWING Hans Göteborg University Sweden [email protected] ENDLEIN Thomas University of Glasgow United Kingdom [email protected] FLAMBARD Anthony R. Forschungszentrum Juelich GmbH Germany [email protected] FLAMMANG Patrick University of Mons Belgium [email protected] FOREMAN Paul Henkel Corporation USA [email protected] FRENZKE Lena University of Technologies Dresden Germany [email protected] Participant list
Surname First Name Organisation Country Email address
FURTOS Gabriel Babes-Bolyai University of Cluj-Napoca Romania [email protected] FUSI Paola University of Milano Bicocca Italy [email protected] GALLI Paolo University of Milano Bicocca Italy [email protected] GONZALEZ RAMON Nieves Feyecon D&I BV The Netherlands [email protected] GRECO Giuliano National Research Council of Italy Italy [email protected] GRIFFET Aude Free University of Brussels Belgium [email protected] GROPEANU Radu Max Planck Institute for Polymer Research Germany [email protected] GULER Mustafa Bilkent University Turkey [email protected] HABER Meir Biota Ltd Israel [email protected] HENNEBERT Elise University of Mons Belgium [email protected] HIGGINS Laila University College Dublin Ireland [email protected] HORAN Glenn Queens University Belfast Northern Ireland [email protected] KALINOVA Radostina University of Mons Belgium [email protected] KAMPERMAN Marleen Wageningen University The Netherlands [email protected] KASAK Peter Polymer Institute SAS Slovakia [email protected] KEANE Padraig University College Dublin Ireland [email protected] KIWI john Ecole Polytechnique Fédérale de Lausanne Switzerland [email protected] KOERNER Lars Eberhard Karls University, Tübingen Germany [email protected] KROGSGAARD Marie University of Aarhus Denmark [email protected] KUNZ Florian A. University of Salzburg Austria [email protected] LADURNER Peter University of Innsbruck Austria [email protected] LANTERBECQ Deborah University of Mons Belgium [email protected] LECLERE Philippe University of Mons Belgium [email protected] LEJEUNE Annabelle University of Liège Belgium [email protected] LINDER Markus VTT Technical Research Centre of Finland Finland [email protected] LOPES Maria University of Lisbon Portugal [email protected] MANO João F. University of Minho Portugal [email protected] Participant list
Surname First Name Organisation Country Email address
MELZER Bjoern University of Freiburg Germany [email protected] MINOR Jean-Christophe MACtac Europe S.A. Belgium [email protected] NETO Ana isabel University of Minho Portugal [email protected] ONUSSEIT Hermann Henkel AG Germany [email protected] PETRONE Luigi Linköping University Sweden [email protected] POWER Anne Marie National University of Ireland, Galway Ireland [email protected] RISCHKA Klaus Fraunhofer IFAM Germany [email protected] ROEHRIG Michael Karlsruhe Institute of Technology (KIT) Germany [email protected] SAMUEL Diana University of Glasgow United Kingdom [email protected] SANTOS Romana University of Lisbon Portugal [email protected] SCHMITT Christian Eberhard Karls University of Tübingen Germany [email protected] SCHNABELRAUCH Matthias INNOVENT e. V. Germany [email protected] SCHWOTZER Willi Nolax AG Switzerland [email protected] SHERIDAN Christopher University of Mons Belgium [email protected] SOBOLCIAK Patrik Polymer Institute SAV Slovakia [email protected] STEINBRECHER Tina University of Freiburg Germany [email protected] STEINHAUSER Lisa University of Tübingen Germany [email protected] TEKINAY Ayse Bilkent University, Turkey [email protected] THI CHINH NGO University of Mons Belgique [email protected] TOKSOY ONER Ebru Marmara University Turkey [email protected] TOMER Guy LifeBond Inc, Israel [email protected] TOMOAIA-COTISEL Maria Babes-Bolyai University of Cluj-Napoca Romania [email protected] TRAMACERE Francesca Istituto Italiano di Tecnologia Italy [email protected] VAN DE WEERDT Cecile University of Liège Belgium [email protected] VASSALLI Massimo National Research Council of Italy Italy [email protected] VITIELLO Luca Procter & Gamble Belgium [email protected] VOIGT Dagmar Christian Albrechts University of Kiel Germany [email protected] Participant list
Surname First Name Organisation Country Email address
VON BYERN Janek University of Vienna Austria [email protected] ZGHIKH Leïla-Nastasia University of Mons Belgium [email protected] ZHEDEN Vanessa University of Vienna Austria [email protected]
ORAL COMMUNICATIONS
Gluing to survive - Antipredator strategy of salamanders
Janek von Byern 1, Ursula Dicke 2, Ingo Grunwald 3, Norbert Cyran 4 and Stanislav Gorb 5
1 Center for Integrative Bioinformatics Vienna, Max F Perutz Laboratories, University of Vienna, Medical University of Vienna, University of Veterinary Medicine, Vienna Austria 2 Universität Bremen, Abtlg. Verhaltensphysiologie, Institut für Hirnforschung I, Bremen Germany 3 Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM), Department of Adhesive Bonding Technology and Surfaces, Adhesives and Polymer Chemistry, Bremen Germany 4 University of Vienna, Faculty of Life Science, Core Facility Cell Imaging & Ultrastructure Research, Vienna Austria 5 Functional Morphology and Biomechanics, Zoological Institute, ChristianAlbrecht University of Kiel Germany
To date, research on adhesives in nature has been carried out mostly on marine animals (Lee et al., 2006; Flammang, 2006; Kamino, 2006; Smith, 2006). Studies on glue secretions in amphibians are rare even though their bonding strength (up to 2.8 MPa for the Australien frog genus Notaden ) is among the highest within the animal kingdom and is comparable with industrial super glues such as cyanoacrylates (Graham, 2005). When provoked by potential predators, the frog Notaden bennetti secretes a sticky nontoxic material from its dorsal skin (Graham et al., 2006; Tyler, 2010). The secretions transform rapidly into an elastic solid (hydrogel) and adhere tightly to a wide range of materials including glass, plastic, metal and even teflon (Graham, 2005). Studies of their glue nature show that, in a dry state, the secretions contain few carbohydrates and consist mainly of proteins (13-400 kDA). Graham et al. (2005) indicate that the Notaden glue functions rather as a pressure-sensitive adhesive (PSA) than as a more chemical mechanism such as in mussels and barnacles (Kamino et al., 2000; Sagert et al., 2006). Within the amphibians, the salamanders have evolved a wide variety of antipredator mechanisms (Brodie, 1983). The most effective strategies are immobility, tail autotomy, color pattern, various behavior patterns and toxic, repulsive or noxious skin secretions (Brodie et al., 1979; Brodie & Smatresk, 1990). Apart from these tactics, salamanders also utilize adhesive secretions for defense. Behavioral observations have demonstrated the effectiveness of that antipredator strategy (Brodie & Gibson, 1969; Williams & Anthony, 1994). Morphological studies, restricted to Ambystoma , show that the adhesive glands are mainly distributed along the lateral edges of the tail ridge and in the partoid region (Fig. 1). Only one secretory cell type (1.3 mm long, 0.43 mm wide) is known in Ambystoma ; it is surrounded by muscle cells (Brodie & Gibson, 1969). So far, the chemical nature of the glue has not been determined, although proteins and little or no carbohydrates and lipids were demonstrated (Williams & Larsen, 1986). To date, this adhesive antipredator strategy has only been reported in few North American species ( Ambystoma spp., Plethodon spp., Batrachoseps spp. and Bolitoglossa spp.) and morphologically characterized in Ambystoma . In the course of a new research applied project, preliminary studies on the glandular system in salamanders are carried out. Several different salamander species ( Hynobius spp, Ambystoma spp., Plethodon spp.) are currently investigated and its glandular cells in the skin compared. Histochemical analysis of the adhesive gland system of Plethodon glutinosus shows that two gland cells are present. The secretory material of the smaller gland cells consists of neutral sugars (PAS positive) and acidic proteins (Alcian Blue staining at pH 2.5), whereas the granules in the larger cell type only react slightly positively for basic proteins (Biebrich Scarlet pH 8.5). Adhesive properties of the secretion on different surfaces will be characterized using various mechanical tests.
Fig. 1 : Defense posture of Ambystoma. Glandular cells are stippled. Image from Brodie & Gibson (1969).
With this research project we aim is to gain a deeper understanding of biochemical and mechanical principles involved in the salamander glue and bonding formation. The results will contribute to our knowledge of the glandular system and its bonding mechanism. It will reveal new aspects in the diversity of adhesive systems, also allow comparison with other adhesive structures, especially those of the Australian frog Notaden .
JvB acknowledges financial support from the Wiener Wissenschafts- Forschungs- und Technologiefonds awarded to Arndt von Haeseler (CIBIV).
References
1. Brodie, E. D. (1983). Chapter: Antipredator adaptations of Salamanders: Evolution and convergence among terrestical species. In Margaris, N. S., Arianoutsou-Faraggitaki, M., and Reiter, R. J. Plant, Animal and Microbial Adaptations to Terrestrial Environment . Plenum Publishing Corporation. 109-133 2. Brodie, E. D. and Gibson, L. S. (1969): Defensive behavior and skin glands of the Northwestern Salamander, Ambystoma gracile . Herpetologica 25, 187-194. 3. Brodie, E. D., Nowak, R. T., and Harvey, W. R. (1979): The effectiveness of antipredator secretions and behavior of selected salamanders against shrews. Copeia 1979 (2), 270-274. 4. Brodie, E. D. and Smatresk, N. J. (1990): The antipredator arsenal of fire salamanders: Spraying of secretions from highly pressurized dorsal skin glands. Herpetologica 46 (1), 1-7. 5. Flammang, P. (2006). Chapter: Adhesive secretions in echinoderms: An overview. In Smith, A. M. and Callow, J. A. Biological Adhesives . Heidelberg: Springer-Verlag. 183-206 6. Graham, L. D. (2005). Chapter: Biological adhesives from nature. In Bowlin, G. L. and Wnek, G. Encyclopedia of Biomaterials and Biomedical Engineering . Oxon: Taylor & Francis. 1-18 7. Graham, L. D., Glattauer, V., Peng, Y. Y., Vaughan, P. R., Werkmeister, J. A., Tyler, M. J., and Ramshaw, J. A. M. (2006). Chapter: An adhesive secreted by Australian frogs of the genus Notaden . In Smith, A. M. and Callow, J. A. Biological adhesives . Heidelberg: Springer-Verlag. 207-223 8. Kamino, K. (2006). Chapter: Barnacles Underwater Attachment. In Smith, A. M. and Callow, J. A. Biological Adhesives . Heidelberg: Springer-Verlag. 145-166 9. Kamino, K., Inoue, K., Maruyama, T., Takamatsu, N., Harayama, S., and Shizuri, Y. (2000): Barnacle cement proteins - Importance of disulfide bonds in their insolubility. Journal of Biological Chemistry 275 (35), 27360-27365. 10. Lee, B. P., Dalsin, J. L., and Messersmith, P. B. (2006). Chapter: Biomimetic adhesive polymers based on mussel adhesive proteins. In Smith, A. M. and Callow, J. A. Biological Adhesives . Heidelberg: Springer-Verlag. 257-278 11. Sagert, J., Sun, C., and Waite, J. H. (2006). Chapter: Chemical subtleties of Mussel and Polychaete holdfasts. In Smith, A. M. and Callow, J. A. Biological Adhesives . Heidelberg: Springer-Verlag. 125-143 12. Smith, A. M. (2006). Chapter: The biochemistry and mechanics of gastropod adhesive gels. In Smith, A. M. and Callow, J. A. Biological Adhesives . Heidelberg: Springer-Verlag. 167-182 13. Tyler, M. J. (2010). Chapter: Adhesive dermal secretions of the Amphibia, with particular reference to the Australian Limnodynastid genus Notaden . In von Byern, J. and Grunwald, I. Biological Adhesive Systems: from Nature to Technical and Medical Application - Chapter "Characterization of the adhesive systems in cephalopods" . Wien: Springer Verlag. 181-186 14. Williams, T. A. and Anthony, C. D. (1994): Technique to isolate Salamander granular gland products with a comment on the evolution of adhesiveness. Copeia 2 (540), 541. 15. Williams, T. A. and Larsen, J. H. (1986): New function for the granular skin glands of the eastern long-toed salamander, Ambystoma macrodactylum columbianum . Journal of Experimental Zoology 239, 329-333.
Dopa functionalized peptide nanofibers for metal implant surface bioactivation
Mustafa O. Guler, Ayse B. Tekinay and Hakan Ceylan
Bilkent University, UNAM-Institute of Materials Science and Nanotechnology, Ankara, Turkey
We design and synthesize peptide-based, self-assembled nanomaterials for regenerative medicine. These nanomaterials are functionalized with 3, 4- dihydroxyphenyl-L-alanine (DOPA), which is abundantly found in mussel adhesive proteins. We exploit these materials for developing bio-friendly metal implants.
Macrostomum lignano as a model system to study duo-gland adhesive organs of flatworms
Peter Ladurner
Institute of Zoology, Innsbruck, Austria
The flatworm Macrostomum lignano is an emerging model system for developmental- and reproductive biology. M. lignano is a free-living, 1mm sized, member of the marine meiofauna. Permanent cultures can be easily maintained in the lab. In flatworms, stem cells - called neoblasts - can differentiate into all cell types including germ cells. The stem cell system is the basis for the continuous cell renewal throughout the animals’ life and the extraordinary regeneration capacity. After amputation animals can regenerate completely from a tiny head fragment. After tail plate amputation the duo-gland adhesive system is largely recovered within one week. We have established Bromodeoxyuridine labeling of S-phase stem cells and we can apply irradiation to eliminate stem cells. We have further developed tools including in situ hybridization, RNA interference to perform functional knock-down studies, and we generated monoclonal antibodies. Transcriptome- and genome sequencing and assembly are in their final stage. In a recent breakthrough we succeeded in the generation of transgenic M. lignano . M. lignano possesses a duo-gland adhesive system which allows them to adhere and release very rapidly from the substrate. The duo-gland system comprises one viscid gland with electron-dense granules forming the adhesive and one releasing gland with smaller, less dense granules. The cells expel their secretions through an anchor cell, i.e. modified epidermal cells. Little is known on the nature of the adhesive molecules. We aim to analyze the molecular composition of the duo- gland adhesive system to evaluate its potential usability for technical and medical applications. Zwitterionic polymer as tool against biofouling
Peter Kasák, Patrik Sobol čiak, Marek Stach, Zuzana Kroneková and Igor Lacík
Polymer Institute SAS, Bratislava, Slovak Republic
Biofouling is one of the major problems in some biomedical applications or/and marine coating development. The adhesion of cells results reducing of diffusion efficiency or malfunction of devices[1]. Construction of the surface with optimal non fouled properties is required to minimize cell adhesion. Various polyzwitterion materials are one of the best a candidate for superlow biofouling due to their biomimetic character [2,3]. Polyzwitterions form internal salts in monomer units between positive ammonium and negative sulfo, carboxy or phosphate groups. Our current studies are focused on polyzwitterionic materials with either a non- adhesive character or a modulated adhesive character regulated by different external stimuli. Zwitterionic hydrogel layer formation, electrografting or photoimmobilization of polyzwitterion on various surfaces was applied and surface and cell adhesion properties were evaluated. Switchability of adhesive character of polymeric surface by light as external stimuli will be also presented. This work was supported by the Scientific Grant Agency of the Ministry of Education of Slovak Republic under the Grant VEGA No. 2/0152/10.
References
[1] Banerjee I., Pangule., R. C Kane R.S. Adv. Mater. 2010, 23, 690. [2] Lowe A. B., McCormick C. L. Polyelectrolytes and Polyzwitterions: Synthesis, Properties, And Applications ACS Books: Washington DC, 2006. [3] Sobol čiak P., Lacík I., Kasák P. Chem. Papers, 2011, accepted. Biological adhesives as building blocks in nanomaterials
Markus Linder and Paivi Laaksonen
VTT Technical Research Centre of Finland, Finland
In nature biological adhesives show remarkable functions such as binding reversibly or permanently to surfaces and structures under demanding conditions. Such adhesion can give inspiration to new solutions within various fields of engineering technology, forming an expanding part of biomimetics research. One field of considerable interest is the adhesive mechanisms in joining dissimilar materials at different length scales. In composite materials a major goal is to join various building blocks to achieve materials that are very tough and strong at the same time. Recently nanoscale building blocks such as carbon nanotubes and graphene sheets that have excellent mechanical properties have been developed. Yet it s a considerable challenge to combine or “glue” these components together to assemble the composite materials. We have shown that adhesive proteins from fungi can be used for this function resulting in nanocomposite materials assembled by bioadhesives. The use of bioadhesives opens a route to designing functions in a more rational way as recombinant DNA technology offer unmatched possibilities for molecular level design and combination of functions. Wet but non slippery: bioinspired adhesives that work in humid and flooded conditions
W. Jon P. Barnes 1, Aránzazu del Campo 2 and Hans-Jürgen Butt 2
1 Centre for Cell Engineering, Glasgow University, Scotland UK 2 Max-Planck-Institut für Polymerforschung, Mainz, Germany
Tree and torrent frogs are able to adhere and move about their wet or even flooded environments without falling. Their toe pad structure, including channels at different length scales, curved contact geometries and a fluid secretion with particular characteristics seems to play a major role for their adhesive and frictional performance. Understanding and translating nature’s design into new adhesion concepts for artificial systems is the main objective in our project. The attachment pads show a complex surface structure including channels with hexagonal geometries at both micro- and nano-scales and 3D contact geometry. There are mucus glands producing a fluid secretion, extensive fibres running at right angles to the surface, and an inner capillary network that probably acts as a shock- absorber. Properties that make frog toe pads smart adhesives include an ability to adhere to both hydrophilic and hydrophobic surfaces (tree frogs), the ability to adhere to rough surfaces under flooded conditions (torrent frogs) and the ability to self-clean. The main adhesive force underlying adhesion in tree frogs is thought to be capillarity. Although tree frog adhesive forces scale with toe pad area, most equations for capillarity show length scaling. However, with approximate analytical calculations we show that for soft, elastic materials above a critical radius (R), the capillary force increases more steeply and scales with R2. We have prepared structured surfaces with different geometries, combining micro and nano-patterning techniques including both optical and soft lithography with polymeric materials, to obtain hierarchical structures with 3D contact geometry that resemble the structure of tree frog toe pads. Preliminary experiments show that, as in the natural system, such toe pad mimics perform better in friction experiments than unstructured (smooth) surfaces under wet conditions. Toe pad mimics also generate larger pull-off forces when the intervening fluid is toe pad mucus rather than water. The climbing roots of Vanilla spec. - first insights into the attachment system of a monocot
Bjoern Melzer, Valentin Lauther and Thomas Speck
University of Freiburg, Germany
Vanilla (Orchidaceae) is a genus of tropical and subtropical vines which climbs with the help of adventitious roots. These roots enable the plant to grow on various natural and artificial climbing substrates like tree barks and sponge rubber; they even anchor onto leaf blades of the Vanilla itself. We recently started to investigate the form-structure-function-relationships and biomechanics of this attachment system in two species ( Vanilla pompona and V. planifolia ). Former studies on permanent attachment systems of plants concentrated on dicotyledonous plants (e.g. Ficus pumila , Parthenocissus spec., Hedera helix , Pithecoctenium crucigerum ) and to our knowledge this is the first analyses of a monocotyledonous permanent attachment system. In the presentation first results from our anatomical, morphological, and biomechanical studies are shown and compared to data from other species. Small Angle X-ray Scattering for the study of biological adhesives
Havazelet Bianco-Peled
Technion - IIT, Israel
Small Angle X-ray Scattering (SAXS) is a powerful analytical technique for studying structural features on length scales between 1 nm up to about 100 nm. As any scattering process, x-ray scattering is characterized by a reciprocity law, which gives an inverse relationship between the features size and scattering angle. Since nanometric dimensions are enormously large compared to x-ray wavelength, small angle scattering is always observed, and only observed, when electron density inhomogeneities of nanometric size exist in the sample. The problem of small-angle analysis consists of conducting the structural features of these inhomogeneities, such as size, shape or mass, from the interference pattern. In my talk I will describe the principles of the method and demonstrate its application for the characterization of biological adhesives: phenolic polymers from the brown alga Fucus Serratus , and foot protein 1 (Mefp-1) extracted from the blue mussel Mytilus edulis . The self-cleaning properties of the toe pads of tree frogs
Niall Crawford, Thomas Endlein and Jon Barnes
Glasgow University, Scotland UK
Tree frogs use adhesive toe pads for climbing on a variety of surfaces. They rely on wet adhesion, which is aided by the secretion of mucus. Naturally, the pads get contaminated regularly through usage, but still maintain their stickiness over time, and so must be able to recover adhesive and friction forces rapidly, without grooming. Here we show in two experiments that the toe pads of White’s tree frogs (Litoria caerulea ) quickly recover from contamination: we compared adhesive forces prior to and after contamination of 1) the whole animal on a rotatable platform and 2) of individual toe pads in restrained frogs mimicking individual steps using a motorised stage. In both cases, the adhesive forces recovered after a few steps, as in geckos and insects, but took significantly longer in restrained frogs. The whole animal experiments showed that the use of the pads increases recovery, when compared to stationary pads. The single toe pad experiment showed that the application of a shear movement of the pad on the surface will greatly improve recovery, for both a partial and full contamination. We think that both shear movements and a “flushing” effect of the secreted mucus play an important role in shedding off particles/contaminants.
Dosima fascicularis : a barnacle, which floats rather than sticks
Vanessa Zheden 1, Ingo Grunwald 2 and Waltraud Klepal 1
1 Core Facility of Cell Imaging and Ultrastructure Research, University of Vienna, Austria 2 Department of Adhesive Bonding Technology and Surfaces, Fraunhofer Institute for Manufacturing Technology and Advanced Materials, Bremen, Germany
Adhesives are used by many organisms in different ways for e.g. prey capture, defence, camouflage, locomotion, bonding or attachment. Very interesting are marine sessile organisms, like mussels, tubeworms and barnacles. They produce a proteinaceaous adhesive to attach permanently to rocks or other surfaces. Understanding these natural adhesives may lead to future technologies in underwater attachment (Kamino, 2008). In this study we focus on the morphology of the cement apparatus of the stalked barnacle Dosima fascicularis . The cement of this species differs greatly from that of any other barnacle. The animal produces a high amount of foam-like cement and may use it as a float, which gives the organism some mobility. Only little is known about the cement apparatus of stalked barnacles, e.g. Lacombe and Liguori (1969) analysed Lepas anatifera and Walker (1974) Octolasmis mülleri . During development the cement glands of Dosima fascicularis grow and change their appearance. They are round or oval when they are young and ellipsoidal in the mature stage. In the young cells the nucleus is round and has one nucleolus only. In the mature cells it is ovoid, highly lobed and has numerous nucleoli. In the young cells the rER is vesicular, in the mature cells the rER-cisternae are stacked and form undulating ribbons. Every gland cell is in connection with the cement canal system in which four sections can be distinguished morphologically by the surface structure of the specific apical cell walls. These canals transport the cement from the glands through the base of the stalk, where the cement is extruded and hardens in contact with the substratum. The cement outside the peduncle has a foam-like structure with bubbles enclosed. Two regions can be distinguished in the cement float: the outer region with closely packed small round and some larger ovoid bubbles and the interior region with large round bubbles, which have a reticulate wall. In sections, the cement appears fibrous. Around the bubbles the fibers are condensed.
References
K. Kamino, Marine Biotechnology 10 (2008), p. 111-121. D. Lacombe and V.R. Liguori, The Biological Bulletin 137 (1969), p. 170-180. G. Walker, The Biological Bulletin 147 (1974), p. 678-689. Study of biological adhesives using cryo-scanning electron microscopy
Dagmar Voigt and Stanislav Gorb
Functional Morphology and Biomechanics, Zoological Institute, Christian Albrechts University of Kiel, Germany
Cryo-scanning electron microscopy (cryo-SEM) provides a rapid and effective method of visualizing adhesive fluids at high resolution. The interface between the fluid and different surfaces, wetting and detailed structural properties may be analysed. In contrast to conventional SEM, samples are neither dried nor treated with solvents that may wash out fluid layers from surfaces, but rather in native frozen condition. The cryo-SEM technique was successfully applied for visualizing tiny secretory droplets in the contact between fly attachment devices (pulvilli) and smooth surfaces (Gorb 2006). Furthermore, adhesive fluids were observed on the surface of attachment devices of moths (Al Bitar et al. 2009) and mirid bugs (Voigt et al. 2007). Fluids were visualised in staphylinid and scarabeid beetle mouthparts (Betz et al. 2008, Karolyi et al. 2009). Insect egg glue was studied in Asparagus beetles (Voigt & Gorb 2010). Cryo-SEM technique was also applied to non-animal fluid-related systems, such as glandular secretions of plant trichomes (Gorb et al. 2007, Voigt & Gorb 2008), hydrated wood (Roth-Nebelsick et al. 2010), nectar droplets on the flower surface, and fungi adhesives (McCully et al. 2009). At the Department of Functional Morphology and Biomechanics in Kiel, we use SEM Hitachi S-4800 (Hitachi High-Technologies Corp., Tokyo, Japan) equipped with a GATAN ALTO-2500 Cryo preparation system (Gatan Inc., Abingdon, UK). Samples are tightly clamped or glued on metal holders, and frozen in liquid nitrogen in a slush chamber (vacuum 10-3 mbar). After freezing, samples are immediately transferred to the cooled (-140°C) preparation chamber of the Cryo -SEM. Before observing the samples, sublimation of frost may be performed for several minutes at temperatures commonly between -90°C and -95°C. After sublimation , samples are sputtered with gold-palladium (6 nm layer thickness) and examined in the cryo-SEM at a low accelerating voltage 0.5-3.0 kV at the temperature of -120°C. Additionally, the cryo preparation chamber is equipped with a cold scalpel with a long, user-controlled handle for sample fracturing. In fractured samples inner details of the structure can be visualised. The scalpel may be also used to fracture adhesive fluids located on surfaces to get e.g. information about the contact area. The cryo-SEM approach may aid in understanding (1) the wetting of surfaces by adhesives, (2) the interface between surfaces and adhesives, (3) the contact area of adhesives, and (4) the composition of adhesives (involved phases, fibres, matrices). However, obtained results have to be interpreted cautiously, because of some cryo-preparation artefacts. Taking together, Cryo-SEM method has a great potential for application in the future research on biological and bio-inspired adhesives.
References
Al Bitar, L., Voigt, D., Zebitz, C. P. W., Gorb, S. N. 2009. Tarsal morphology and attachment ability of the codling moth Cydia pomonella L. (Lepidoptera, Tortricidae) to smooth surfaces. Journal of Insect Physiology 55: 1029-1038. Betz, O., Koerner, L., Gorb, S. N. 2008. Von der Natur lernen. Insektenzunge als Vorbild für biphasisch viskose Klebstoffe? Adhäsion 6: 38-41. Gorb, S. N. 2006. Fly microdroplets viewed big: a Cryo-SEM approach. Microscopy Today 14: 38-39. Gorb, S. N., Voigt, D., Gorb, E. V. 2007. Visualisation of small fluid droplets on biological and artificial surfaces using the cryo-SEM approach. In Modern Research and Educational Topics in Microscopy, Microscopy Series 2 (ed. Méndez-Vilas and J. Díaz), pp. 812-819. Badajoz: Formatex. Karolyi, F., Gorb, S. N., Krenn, H. W. 2009. Pollen grains adhere to the moist mouthparts in the flower visiting beetle Cetonia aurata (Scarabaeidae, Coleoptera). Arthropod-Plant Interactions 3: 1-8. McCully, M. E., Canny, M. J., Huang, C. X. 2009. Cryo-scanning electron microscopy (CSEM) in the advancement of functional plant biology. Morphological and anatomical applications. Functional Plant Biology 36: 97–124. Roth-Nebelsick, A., Voigt, D., Gorb, S. 2010. Cryo-scanning electron microscopy studies of pits in Pinus wallichiana and Mallotus japonicus . IAWA Journal 31: 257-267. Voigt, D.; Gorb, E.; Gorb, S. (2007): Plant surface–bug interactions: Dicyphus errans stalking along trichomes. Arthropod-Plant Interactions 1: 221-243. Voigt, D., Gorb, S. 2008. An insect trap as habitat: cohesion-failure mechanism prevents adhesion of Pameridea roridulae bugs to the sticky surface of the plant Roridula gorgonias . Journal of Experimental Biology 211: 2647-2657. Voigt, D., Gorb, S. 2010. Egg attachment of the asparagus beetle Crioceris asparagi to the crystalline waxy surface of Asparagus officinalis . Proceedings of the Royal Society B 277: 895-9003. Settlement assays of Balanus amphitrite cyprids
Luigi Petrone 1, Alessio Di Fino 2, Nick Aldred 2, Pitsiri Sukkaew 3, Thomas Ederth 3, Anthony S. Clare 2 and Bo Liedberg 1
1 Division of Molecular Physics, IFM, Linköping University, Sweden 2 School of Marine Science and Technology, Newcastle University, United Kingdom
Barnacles are particularly pervasive foulers, causing considerable issues for underwater man-made structures and ship’s hulls due to their relatively large size, hard-calcareous form and gregarious nature (1). It is therefore critical to gain a better understanding of cyprids adhesion to develop new and effective fouling-resistant coatings. Settlement assays of Balanus amphitrite cyprids were initially conducted on microscope glass slides, with the expectation that the cyprids would settle in high number. On the contrary, several settlement assays showed negligible percentages of attached individuals. Similarly, cyprids were placed on CH3 and OH terminated self-assembled monolayers (SAMs) created on gold-coated microscope slides, resulting once more in negligible settlement. These results demonstrated that microscope slides are not the ideal substrate for settlement assays of B. amphitrite cyprids, since little or no settlement was noticed. An alternative assay method was therefore needed and polystyrene (PS) well plates showed promising settlement results, with cyprids adhering with higher density than on microscope slides. PS plates were then gold-coated in a modified evaporation chamber to ensure gold deposition homogenously within the wells. Subsequently, a range of SAMs was formed in the wells, and settlement tests were conducted. Cyprids were observed to settle preferentially on negatively-charged surfaces, with neutral surfaces intermediate, and positively-charged SAMs received the lowest settlement (2). No correlation was found between settlement and wettability, as previously suggested in literature.
References
1. M. P. Schultz. Effects of coating roughness and biofouling on ship resistance and powering. Biofouling 23, 331–341, 2007. 2. L. Petrone et al. Settlement assays of Balanus amphitrite cyprids on self-assembled monolayer surfaces. To be submitted in Biofouling In-vitro adhesion assay – Skin surface model
Meir Haber
Biota Ltd., Or Akiva, Israel
Skin model composition consisting mainly of gelatin, polysaccharides and lipids was developed. The model is a film material simulating mechanical and surface properties of a human skin. Comparison of the results, obtained using the model and real skin, shows close values of adhesion strength on removal of commercial surgical tapes from both substrates. The model is suitable as a substrate for gluing experiments when adhesion-to-skin should be tested. The composition components are commercially available and affordable. The model is useful for routine laboratory handling, avoids the variability associated with biological specimens and ensures results correlated to in-vivo human skin. Technology of the model preparation is simple and properties of the model may be tailored to simulate skin variability. Large surface can be prepared in a standard chemical laboratory by standard equipment. Permanent attachment pads of Parthenocissus spec. – morphology and biomechanics
Tina Steinbrecher 1,2 , Sven Bundschuh 1, Thomas Speck 2, Oliver Kraft 1 and Ruth Schwaiger 1
1 Karlsruhe Institute of Technology, Germany 2 Plant Biomechanics Group Freiburg, University of Freiburg, Germany
The climbing plants Parthenocissus tricuspidata and Parthenocissus quinquefolia achieve permanent attachment through adhesive pads. In both plants, those highly efficient structures secrete an adhesive fluid and were found to attach to a wide variety of substrates, both organic and inorganic. The development of the attachment pads and the characteristics of the attachment are affected by the substrate. Biomechanical investigations on different length scales indicate a strong influence of the structural design of the pads on the mechanical properties. For example, the stiffness of the pads in the plane of the interface shows differences between central and peripheral regions. Furthermore, tensile tests on lignified pads show that a pad is able to withstand normal stresses at the interface of up to 4 MPa while failure never occurred only at the interface. The attachment pad morphology and the attachment strength in terms of the substrate and the attachment procedure will be discussed. Mechanical properties of dual curing bone cement based on glass fibers
Gabriel Furtos 1,2 , Cristina Prejmerean 1, Maria Tomoaia-Cotisel 2, Bogdan Baldea 3 and Nicolae Jumate 4
1Raluca Ripan Institute of Research in Chemistry, Babes-Bolyai University of Cluj-Napoca, Cluj- Napoca, Romania 2Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University of Cluj-Napoca, Cluj- Napoca, Romania 3Faculty of Dental Medicine, Timisoara, Romania 4Technical University of Cluj -Napoca, Cluj-Napoca, Romania
Introduction The mechanical properties of polymethylmethacrylate (PMMA) bone cement have been well reported. PMMA provides fixation by mechanical adhesion but does not offer direct bonding with surrounding bone. The limitations associated with PMMA includ the presence of toxic residual monomers and weak mechanical properties in tension. The aim of this study was to obtain new dual curing bone cements based on glass fibers, barium sulfate powder and polymeric matrix and to investigate their mechanical properties and radiopacity.
Materials and methods Bone cements based on BIS-GMA/TEGDMA monomers with different powder/liquid ratio: 25/75, 30/70, 40/60 was used to obtain new dual curing bone cements. The inorganic fillers used were barium sulfate (20% wt.) and AR glass fibers (5%, 10%, 20% wt.) of 1 mm length. To explore the influence of glass fibers on mechanical properties of new bone cements we prepared samples made of polymers and bone cements with barium sulfate (20% wt.). Bone cements were cured using light cured, self cured and dual cured system (light cured and self cured). The resulted materials were sudied for the ultimate compressive strength (UCS), compressive yield strength (CYS), diametral compressive strength (DTS), compressive modulus (CM) and radiopacity. The surface morphologies and chemical composition of DTS fractured samples were characterized by SEM, EDX and AFM. Results UCS of experimental bone cements showed a slow decrease with increasing of the amount of glass fibers from 5%, 10% to 20% wt. CYS, CM, DTS and radiopacity increased with increasing the glass fiber amount in bone cements. The mechanical tests reveal that the mechanical properties increase in the following order: light curing cements < self curing cements < dual curing cements. SEM images showed that the fibers bridge the cracks and increase the resistance of these materials against the propagation of the fissures in the direction of fracture. Conclusions The addition of glass fibers to the cements were found to increase CYS, CM, DTS and radiopacity. UCS values for experimental glass fiber cement tested was higher than 70 MPa, and the radiopacity was higher than 1 mm Al, a limit requested by ISO 4049: 2000. The proposed naterials in this study were bicomponent cements which could be used in bone surgery or dental field. The possibility of light curing could be an advantage if a short time of curing is needed.
ACKNOWLEDGEMENTS: The study was done within the frame of the COST Action TD0906 Biological adhesives from biology to biomimetics. One of the authors (GF) was financially supported by POSDRU/89/1.5/S/60189 Grant. Asymmetric spatula heads combined with lateral forces provide a mechanism for controlling the adhesive attachment of a range of spider species
Padraig Keane, Mads Bruun Hovgaard, Anika Mostaert, Suzi Jarvis
Nanoscale Function Group,Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Ireland
Dry adhesion is a common strategy utilized thoughout nature, allowing reversible attachment of animals to a large range of surfaces. It enables the animal to switch rapidly and safely between attachment and detachment by simply altering the direction of a force applied laterally to the feet. Here we investigate the dry adhesive system of a number of spider species from both the Mygalomorph and Araneomorph clades. Three representatives of the Mygalomorphae were examined, along with two Araneomorph species. Atomic force microscopy (AFM) was used to measure the adhesive strength of a single setule. Secondly, scanning electron microscopy (SEM) was used to observe and measure the adhesion of a spider seta to an AFM cantilever tip and to estimate the adhesive force between them. Finally, a seta (with attached setules) was dragged across a spherical surface to investigate whether the measured adhesive force changes depending on the direction of relative movement between the seta and the surface. The AFM-measured values for adhesion of single spider setules perpendicular to a surface (9-16 nN) were similar to values predicted by the Johnson-Kendall- Roberts (JKR) model of elastic contact (Johnson et al. 1971). In contrast, the force of adhesion, measured by SEM, between the seta and the cantilever reached values as high as 10µN, much higher than predicted by JKR theory alone. The applied lateral force aligned the setules to ensure a large contact area, and thus increases adhesion. Finally, it was observed that significantly higher adhesion occurred when the setules were dragged laterally across a spherical surface in the proximal direction (i.e., towards the spider’s tarsus). When pushed in the opposite direction, adhesion was greatly reduced. This confirms that the spider dry adhesive system is another example of a directional adhesive, comparable to the well characterised gecko dry adhesive system.
Reference
Johnson, K. L., K. Kendall and A. D. Roberts. 1971. "Surface energy and contact of elastic solids." Proceedings of the Royal Society of London Series a-Mathematical and Physical Sciences 324(1558):301-313. Adsorption properties of mussel based peptide sequences
Klaus Rischka, Marc Amkreutz, Gabriela Diaconu and Katharina Richter
Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM), Germany
Mussels have the capability to stick on nearly every kind of materials like wood, stones, metals and plastics like PTFE. The composition of this protein based adhesive is well known currently. But the knowledge about the molecular interactions of the proteins and their amino acids, responsible for the remarkable adhesion properties, with different surfaces is limited. This knowledge is essential creating new artificial bioinspired adhesives with comparable characteristics or well adjusted adhesive properties. Different peptide sequences derived from Mefp-1 were synthesized by solid phase peptide synthesis for the evaluation of the influence of the “key” amino acid DOPA, its oxidation state and the length of peptide chains. The quartz crystal microbalance (QCM) technique is one of the methods of choice for the determination of substrate/peptide interactions. The investigations are supported by calculations of dissolved and adsorbed peptide structures using the conformers sampling. Additionally the tensile strengths of peptide glued tooth fragments were determined. Thin nanostructured bioactive films by MAPLE assembling
Ebru Toksoy Oner 1 and Ion N. Mihailescu 2
1 Marmara University, Department of Bioengineering, Istanbul, Turkey 2 National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, Magurele, Romania
Levan is a long linear homopolymer of β(2-6) linked fructose residues and it is a water soluble, strongly adhesive and film-forming biopolymer. It has many potential uses as emulsifier, stabilizer and thickener, encapsulating agent, osmoregulator and cryoprotector in food, cosmetics, pharmaceutical or chemical industries. In medicine, levan is used as plasma substitute, prolongator of drug activity, radio protector, antitumor and antihyperlipidemic agent (1). Levan by Halomonas sp. has recently been reported as a good candidate for development of nanocarrier systems for peptide and protein drug delivery (2). Considerable decrease in the fabrication expenses of this polymer has been reported by optimization of fermentation conditions in large-scale levan production by Halomonas sp. bioreactor cultures (3). On the other hand, levan coatings could have great commercial potential for specific applications. Currently, films of polymers with desired shape and area are obtained by solvent casting or thermal processing. Presently, drug tablet coatings consist of polymer and polysaccharide, with plasticizers and pigments included. By extrusion and molding there were prepared hundreds of microns thick films of levan by adding glycerol as a plasticizer (4). However, as known, the thicker the film the higher are the risks of poor adhesion, cracking or easy peeling thus making impossible to control the film dissolution. Films at nanometric scale would reduce the cost of production and increase the specific surface area. For drug release and delivery, thin coatings of desired thickness would be attractive to control the rate of dissolution in the gastrointestinal tract since some drugs are absorbed better at different points in the digestive system. Nanostructured layers could boost the potential of biopolymer surface for applications as nanocarriers or drug delivery. Moreover, uniform distribution on different collectors allows for a wide range of new uses, especially in biology and medicine. Matrix assisted pulsed laser evaporation (MAPLE) was developed for the controlled growth of biopolymer thin films. In MAPLE, the laser-induced material ejection is generated backward from solid cryogenic targets and the expulsed substance assembled on specific collectors. Typically, the targets consist of the organic complex dissolved into a laser wavelength absorbing solvent when frozen. At rather low laser fluences, the thermal and chemical decomposition are minimal, even excluded, and the safe transfer of the organic compound is ensured. The method permitted the fabrication of micro- or nano-arrays of wide-ranging biomaterials with applications in optoelectronics, biosensing, chemical sensing, biochemical analysis as well as for drug delivery systems and implant development (5). In this study, MAPLE was used to obtain nanostructured thin films of levan and oxidized levan under vacuum conditions. The obtained films preserved the base material composition as confirmed by FTIR. They were compact with high specific surface areas as demonstrated by scanning electron and atomic force microscopy investigations. The coatings presented a good adhesion to substrate and a uniform, homogenous nanostructured surface. The high specific surface areas are fully compatible with potential use in biology or medicine. Cell viability and proliferation studies confirmed the biocompatible behavior of the synthesized nanostructures. The oxidized levan thin films induced an increase in cell proliferation as compared with the simple levan coatings. This result is in good agreement with the contact angle data which evidenced a higher hydrophilicity in case of oxidized levan samples which was assigned to the acidic aldehyde-hydrogen bonds forming after oxidation (6).
References
1. Kang, S.A.; Jang, K.H.; Seo, J.W.; Kim, K.H.; Kim, Y.H.; Rairakhwada, D.; Seo, M.; Lee, J.O.; Ha, S.D.; Kim, C.H.; Rhee, S.K. Levan: applications and perspectives; Rehm, B.H.A., Eds.; Caister Academic Press, 2009. p 145. 2. Sezer, A.D.; Kazak, H.; Toksoy Oner, E.; Akbuga, J. Carbohyd. Polym. 2011, 84, 358. 3. Küçüka şık, F.; Kazak, H.; Güney, D.; Finore, I.; Poli, A.; Yenigün, O.; Nicolaus, B.; Toksoy Öner, E. Appl. Microbiol. Biot. 2011, 89, 1726. 4. Barone, J.R.; Medynets, M. Carbohyd. Polym., 2007, 69, 554. 5. Floroian, L.; Sima, F.; Florescu, M.; Badea, M.; Popescu, A.C.; Serban, N.; Mihailescu, I.N. J. Electroanal. Chem. 2010, 648, 111. 6. Sima, F., Esra Cansever Mutlu, Mehmet S. Eroglu, Livia E. Sima, L.E., Serban, N.; Carmen Ristoscu, Stefana M. Petrescu, Ebru Toksoy Oner, Ion N. Mihailescu, Biomacromolecules, in press. Fabrication of hierarchical Gecko-mimicking structures
Michael Röhrig, Farid Oulhadj, Alexander Kolew, Fabian Pfannes, Matthias Worgull and Hendrik Hölscher
Institute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT), Germany
Despite their weight of several hundred grams, Geckos are very famous for their climbing abilities. Their impressive attachment system is based on the structure of their toes. The toes of the Tokay Gecko for example are divided into several lamellae which are covered with millions of delicate hairs, the so-called setae, which are about 100 µm in height and 4 µm in diameter. The setae branch into hundreds of tiny endings, the so-called spatulae. Thus the gecko is capable of achieving intimate contact with smooth and rough surfaces which leads to a strong adhesion due to intermolecular forces, in particular van der Waals forces. Mimicking these micro- and nanostructures leads to artificial dry attachment systems. In our presentation we will discuss two methods, suitable for the flexible and accordingly cost-effective development and manufacturing of hierarchical gecko-type structures. The technique of 3D laser lithography allows for the fabrication of arbitrary 3D nanostructures in suitable photoresists and is based on multiphoton polymerization [1]. By using this easily adaptable technique, hierarchical structures haven been created. Hot pulling [2] is a recently introduced modified hot embossing process [3], enabling the large area fabrication of delicate polymer fibrils with highest aspect ratios and diameters in the nanometer range. By combining classical hot embossing and hot pulling, hierarchical gecko-mimicking structures can be fabricated.
References
[1] M. Thiel et al., Appl. Phys. Lett. 97, 221102 (2010) [2] Patent WO 2010 /049081 [3] M. Worgull: Hot Embossing - Theory and Technology of Microreplication, Elsevier Science; William Andrew, ISBN-10: 0815515790 (2009). Stress analysis and parameter study of permanent attachment pads of Parthenocissus tricuspidata by Finite Element simulations
S. Bundschuh 1,T. Steinbrecher 1,2 , R. Schwaiger 1, O. Kraft 1,T. Speck 2 and C. Eberl 1
1 Institute for Applied Materials, Karlsruhe Institute of Technology, Germany 2 Plant Biomechanics Group Freiburg, University of Freiburg, Germany
Permanent attachment structures of climbing plants have already been described by Darwin and their outstanding mechanical performance has been recognized. The adhesive pads of Parthenocissus tricuspidata attach within few hours after making contact with the substrate and stay attached for many years after lignification. Our previous studies of the structure and the mechanical behaviour on different length scales indicate a highly complex interaction between the different structural components of the pads, which are further investigated using finite element simulations. Different geometrical models reflecting both simple and complex geometries were designed with the goal to obtain a better understanding of evolutionary changes of the pad geometry. The influence of the different structural regions of a pad on the stress distribution in the pad is investigated through systematic parameter studies. Development of new multilayer films based on chitosan and dopamine-modified hyaluronic acid
Ana Cibrão 1,2 , Gloria G. Ferrer 3,4,5 , Gabriela Botelho 6, Natália M. Alves 1,2 and João F. Mano 1,2
1 3B´s Research Group – Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine. AvePark, 4806-909, Taipas, Guimarães, Portugal. 2 IBB – Institute for Biotechnology and Bioengineering, PT Associated Laboratory, Guimarães, Portugal. 3 Center for Biomaterials and Tissue Engineering, Universidad Politécnica de Valencia, 46022, Valencia, Spain. 4 Biomaterials Unit, Centro de Investigación Príncipe Felipe, 46013 Valencia, Spain. 5 Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Valencia, Spain. 6 Dept.de Química,Universidade do Minho,Campus de Gualtar, 4710-057 Braga, Portugal.
Marine mussels secrete adhesive proteins that strongly adhere to both organic and inorganic surfaces in aqueous environments [1]. These proteins present an unusual amino acid, 3,4-dihydroxy-L-phenylalanine (DOPA) [2], which contain catechol groups. The outstanding adhesive properties of these materials, still unmatched by human technology, have been attributed to the high concentration of DOPA residues and, in particular, to the presence of such catechol groups [3]. Inspired by the structure and properties of mussel adhesive proteins, we built new layer-by-layer (LbL) films based on polymers that contain catechol groups. We expect that such materials will present an enhanced cell adhesion when they are applied in biomedical applications. The LbL films were prepared by using chitosan and dopamine modified hyaluronic acid. The catechol group can be found in dopamine. The dopamine-hyaluronic acid conjugates were prepared by using conventional carbodiimide chemistry. The conjugates were characterized by distinct techniques, such as nuclear magnetic resonance (NMR) and ultra-violet spectrophotometry. The formation of the films was investigated in detail and in-situ as a function of distinct parameters (such as pH and concentrations of the polymeric solutions) by using the quartz-crystal microbalance (QCM-D) technique, in order to find in which conditions it is possible to assemble the films. A study of the adhesion properties of the developed films to distinct substrates, such as metals and glass, was also conducted.
References
1. Ku, S.H., et al., General functionalization route for cell adhesion on non-wetting surfaces. Biomaterials, 2010. 31(9): p. 2535-2541. 2. Guvendiren, M., P.B. Messersmith, and K.R. Shull, Self-Assembly and Adhesion of DOPA-Modified Methacrylic Triblock Hydrogels. Biomacromolecules, 2008. 9(1): p. 122-128. 3. Sever, M.J., et al., Metal-Mediated Cross-Linking in the Generation of a Marine-Mussel Adhesive. Angewandte Chemie International Edition, 2004. 43(4): p. 448-450. Design, synthesis and characterization of artificial bioinspired adhesives
Marleen Kamperman
Wageningen University, Physical Chemistry and Colloid Science, Netherlands
Biology offers multitudes of structures in different plants and animals, the functionalities of which have inspired scientists to the design of advanced material systems. For example, the remarkable attachment systems of spiders, flies and geckos enables them to firmly adhere and easily detach from almost any kind of surface, due to the microtopography of the toe pads combined with optimized biomechanics. We develop micro- and nanostructured surfaces using different patterning technologies such as photolithography, template molding and confined block copolymer self-assembly. Using model systems we investigate the effect of material properties and geometry on adhesive forces and energies. These geometry-property relationships are used to guide the design of novel bioinspired artificial adhesives. Here, we demonstrate that responsive polymer materials can be used to create microstructured surfaces with actuated adhesion. Application of an external field (e.g. thermal, magnetic or pressure) causes changes in the topographical pattern and this influences the final adhesion performance. For example, micropatterned polydimethylsiloxane (PDMS) surfaces with pillars of 30 m length and 10 m diameter were used to show adhesion actuation using pressure. For low and moderate applied compressive preloads, measured adhesion was 7.5 times greater than on flat controls whereas for high applied preloads adhesion dropped to very low values. In situ imaging shows that the increased preload caused the pillars to deform by bending and/or buckling and to lose their adhesive contact. The elasticity of PDMS aids the pillar recovery to the upright position upon removal of preload enabling repeatability of the switch. Such active structures may have interesting applications in responsive systems where adhesion or friction management is required.
POSTERS
Inspired by marine adhesives: production and characterization of green adhesion promoters for metal coating
Pierre Becker 1, Elise Hennebert 1, Annabelle Lejeune 2, Cécile Van De Weerdt 2, Joseph Martial 2, Déborah Lanterbecq 3, Mélanie Jeusette 3, Pascal Damman 3, Catherine Archambeau 4 and Patrick Flammang 1
1 Marine Biology Laboratory, University of Mons-UMONS, Belgium 2 Molecular Biology and Genetic Engineering Unit, University of Liège, Belgium 3 InFlux Laboratory, University of Mons-UMONS, Belgium 4 ArcelorMittal Liège Research, Liège, Belgium
There is a need in the metallurgical industry for the development of a green and universal adhesion promoter working on different types of steels and allowing the coupling of various polymers, including paints. Some marine animals could provide an elegant solution as they are able to adhere quickly and strongly to metal surfaces at ambient temperature and in a wet environment. These organisms produce adhesive proteins with special features such as a biased amino acid composition, repeated motifs or post-translational modifications. The objectives of this biomimicry- related project are (1) to characterize these proteins (primary structure and modifications), (2) to ensure their production by bacteria and (3) to analyse their efficiency as adhesion promoter. Three invertebrate species are studied: the mussel Mytilus edulis , the tube-dwelling worm Sabellaria alveolata , and the sea star Asterias rubens . The adhesive proteins of the mussel are already well-known and provide a point of comparison. Among mussel adhesive proteins, those situated at the interface between byssus threads and the substratum (Mefp-3 and -5) were chosen. In S. alveolata , three proteins were characterized. Two of them, named Sa-1 and Sa-2, are positively-charged and share common features such as basic pI, mass, amino acid composition and presence of DOPA and repeated patterns. A third protein (Sa-3), negatively-charged and rich in phosphoserine, was also identified. In A. rubens , 11 of the proteins extracted from the adhesive material were not identified in databases and may correspond to novel adhesive proteins. One of them is a glycoprotein and another one is a phosphoglycoprotein. After synthesis of the coding gene, the adhesive proteins Mefp-3 and -5, Sa-1, Sa-2 and Sa-3 were produced in Escherichia coli either in their full form or in a constructed multimeric form based on the repetitive pattern of their sequence. Mefp-3 and Sa-1 full forms have been successfully produced and purify at around 50 mg of pure protein per liter of culture while a yield of 10 mg/l was obtained for the multimeric forms of Sa-1 and Sa-2 (8 and 16-repeat patterns, respectively). Following purification, the proteins have to be modified to mimic the natural adhesives. Transformation of the tyrosine residues into DOPA is currently investigated through chemical and enzymatic approaches. Finally, the physico-chemical properties of the synthesized recombinant proteins were studied. In particular, the mussel protein Mefp-3 was investigated as promoter for paint binding on metallic surfaces. The adhesive performance of the protein layer was tested using bonding-debonding tests (probe-tack experiment). Different parameters (e.g., layer thickness) were analyzed and results were compared with effective industrial systems in terms of adhesion force/energy. Sea-cucumber Cuvierian tubules: A unique marine biological adhesive
Mélanie Demeuldre, Pierre Becker and Patrick Flammang
Marine Biology Laboratory, University of Mons-UMONS, Belgium
Marine bioadhesive research has been gaining increasing interest because of its high potential for the development of novel adhesives for technological applications. In the search for new bioadhesion models, we investigated Cuvierian tubules, a specialized defense system found in some species of holothuroids (sea cucumbers). When stressed, individuals from these species expel a few tubules, which lengthen considerably and become sticky upon contact with any object. Their biomechanical properties make Cuvierian tubules very efficient at immobilizing potential predators. In terms of composition, their adhesive consists of 40% neutral carbohydrates and 60% proteins, with a large part of small side-chain amino acids as well as charged and polar amino acids. This composition is unique among the adhesive secretions of marine invertebrates. Three methods were used to characterize further the composition of the adhesive associated with Cuvierian tubules. First, proteins were extracted from glue prints using a protocol developed in our laboratory. Glue prints, which consist of patches of adhesive material left on the substratum after mechanical detachment of the tubule, are indeed extremely enriched in adhesive secretions. After separation and enzymatic digestion, the extracted proteins were analysed with tandem mass spectrometry which yielded a recurrent de novo generated peptide sequence rich in glycine. This sequence was used to design degenerated primers that were subsequently used for cloning and sequencing Cuvierian tubule cDNAs. Secondly, based on the detection of polyphosphoproteins in tubule sections, a Western blot was performed with an anti-phosphoserine antibody and showed the presence of a 24 kDa protein. This protein however could not be identified using mass spectrometry and further experiments are needed to obtain more information on its identity and sequence. Finally, a random screeening was performed on a Cuvierian tubules cDNA library. Fifty clones were sequenced highlighting two interesting results: (i) a sequence rich in proline and glutamine and (ii) a second sequence related to a fibrinogen, a molecule responsible for coagulation. The uniqueness of the Cuvierian tubule adhesive and its ability to form strong adhesive bonds in a few seconds are properties important for the development of water- resistant adhesives.
Sticky secret(ion)s: the attachment mechanisms of Peperomia fruits
Lena Frenzke
University of Technology Dresden, Germany
The genus Peperomia Ruiz & Pav. is the second largest genus of Piperaceae and belongs with 1500-1700 species to the so-called “big plant genera” of angiosperms. Most of the epiphytic Peperomia species bear sticky fruits with either pappilae or a so-called pseudocupula on the fruit surface. Peperomia clades which possess these structures are wider distributed and comprise more species than clades lacking these characters. Although the knowledge on Peperomia fruit dispersal is sparse, the adhesive secretions are most likely attachment mechanisms addressing dispersing animals as vectors. In our study we will characterize the two attachment mechanisms (pappilae vs. pseudocupula) by 1) measuring the pull-off forces of the fruits, and 2) analyzing the adhesion strength of the Peperomia adhesive substances on different substrates and surfaces. Preliminary data suggest that Peperomia adhesives are composed of a multicomponent system containing both fibrillar and viscous components. However the composition of the sticky excretions needs further investigation. Probing attachment in the free living microturbellarian Macrostomum lignano
Glenn Horan, Paul McVeigh, Louise Atkinson, Angela Mousley, Nikki J. Marks and Aaron G.Maule
Queens University Belfast, Northern Ireland
There has been an increasing amount of literature published investigating the function and distribution of different neuropeptides in the Platyhelminthes due to their value as a putative drug target system in parasitic flatworms. Using BLAST tools, we have identified a variety of novel neuropeptides in Macrostomum lignano and hope to identify those involved in the attachment process. As a first step to probing their function, we have used immunocytochemistry (ICC) and confocal scanning laser microscopy (CSLM) to map the expression of selected novel neuropeptides in M. lignano . We found that one of the peptides (AGQRWSSGF- NH2) localised to a large number of cell bodies in the tail plate, adjacent to the adhesive organs and suggesting a role in attachment. M. lignano is already in use as a model organism for the study of parasitic flatworms and in studies on regeneration. Here, we propose its use in the study of biological adhesion, particularly the duo gland adhesive system used by M. lignano and other marine organisms for temporary attachment. We will be using attachment assays to determine the phenotypic impacts of RNA interference-based known-down of selected neuropeptide gene transcripts to investigate their involvement in adhesive processes. Preparation and characterization of silicone surface coated with biomimetic polymer structures: topography characterization and first adhesion tests
Radostina Kalinova 1, Rosica Mincheva 1, Chinh Ngo 2, Elise Hennebert 3, Philippe Leclére 2, Patrick Flammang 3, Roberto Lazzaroni 2 and Philippe Dubois 1
1Laboratory of Polymeric and Composite Materials, Center for Innovation and Research in Materials and Polymers (CIRMAP), University of Mons-UMONS, Belgium 2Laboratory for Chemistry of Novel Materials, Center for Innovation and Research in Materials and Polymers (CIRMAP), University of Mons-UMONS, Belgium 3Laboratory of Marine Biology, University of Mons-UMONS, Belgium
Some of the best prototypes for adhesion in nature are represented by gecko, a kind of lizard which benefits from its dry adhesion system for locomotion, mussels which favour permanent adhesion with the in situ formation of kind of concrete materials and see stars which rely on adhesive secretions for non-permanent adhesion. As we learn how this living organisms stick we can use this information to create new classes of synthetic materials like bioinspired polymers. Mimicking the biological adhesion systems can also help to solve the drawbacks of conventional adhesives which adsorb contamination, cannot adapt for different exposure conditions and cannot be repeatedly used. For this reason amphiphilic copolymers with one polydimethylsiloxane (PDMS) block and the other block made from acrylic monomers (positively and negatively charged polyacrylic blocks) were synthesis. PDMS macroinitiator carrying active alkyl halide end group(s) was employed in polymerization of N,N-dimethylamino-2-ethyl methacrylate (DMAEMA)[1] and 1- ethoxyethyl acrylate (EEA)[2] monomer by Atom Transfer Radical Polymerization (ATRP). The as obtained PDMS-b-PDMAEMA and PDMS-b-PAA copolymers were used for preparation of films by spin-coating and their topography was characterized by AFM. Microphase separation of the polymers is clearly visible. In the next step the diblock copolymers were dispersed in a PDMS matrix and considered for tuning the surface properties of this condensation-curing silicone coating. Then preliminary adhesion test with sea stars were performed. The results show that the sea stars attached on PDMS and PDMS-b-PDMAEMA but not at all on PDMS-b-PAA. Interestingly enough, footprints of glue are visible on PDMS-b-PDMAEMA.
References
(1) E. Duquesne, J. Habimana, P. Degee, P. Dubois, Macromolecular Chemistry and Physics, 207 (2003); 1116-1125 (2) W.V. Camp, F. Du Prez, Macromolecules 2004, 37(18), 6673 The Calcified holdfast of Anomia simplex and bioinspired glues
Marie Krogsgaard 1, M. Schmidt 1, S. Frølich 1, H. Leemreize 1, K. Henriksen 1, C. Broomell 2, N. Holten-Andersen 2, J.H. Waite 3, H. Birkedal 1
1Department of Chemistry and iNANO, Aarhus University, Aarhus, Denmark 2Department of Chemistry, Institute for Biophysical Dynamics and the James Franck Institute, University of Chicago, Chicago, USA 3Marine Science Institute, University of California, Santa Barbara, USA
The bivalve Anomia , also called jingle shell or mermaid’s toenail, and a few related species adhere to substrates through a mineralized byssus that extends through a notch in the shell side closest to the substrate. Anomia simplex lives attached to shells or small rocks. The byssus is calcified by CaCO3 with both the crystal forms aragonite and calcite present and contains over 90 wt% mineral [1]. The byssus has a highly complex hierarchical structure [1, 2]. The organic parts of the construct are intimately connected with the inorganic phase. We will discuss local mechanical properties of the byssus measured by nanoindentation. These measurements reveal gradients in mechanical properties that allow accommodation of interfaces between stiff substrates and soft muscles. The organic matrix is found to contain proteins as well as highly oriented crystalline chitin. Chitin/protein sheets interface the mineralized byssus with the musculature leading to the top shell. All in all, this points towards a highly complex materials design, where the animal incorporates several inorganic phases, chitin, proteins and hierarchical designs to accommodate the attachment of soft tissue to the very hard substrates on which the animal lives. We will also discuss efforts towards bioinspired materials based on DOPA- carrying synthetic macromolecules as exemplified by reference [3]. Developments of new smart DOPA-functionalized polymers are under way in our laboratory.
We thank the Danish Research Council for Independent Research | Natural Sciences and the Human Frontiers Science Program (grant RGP0004/2010) for funding. References
[1] J.R. Eltzholtz & H. Birkedal “Architecture of the Biomineralized Byssus of the Saddle Oyster (Anomia sp)” J. Adhesion 2009, 85, 590-600 [2] J.R. Eltzholtz, M. Krogsgaard & H. Birkedal “Hierarchical Design and Nanomechanics of the Calcified Byssus of Anomia simplex” In Structure-Property Relationships in Biomineralized and Biomimetic Composites, edited by D. Kisailus, L. Estroff, W. Landis, P. Zavattieri, H. S. Gupta (Mater. Res. Soc. Symp. Proc. Volume 1187, Warrendale, PA) 2009, KK05-09 [3] N. Holten-Andersen, M.J. Harrington, H. Birkedal, B.P. Lee, P.B. Messersmith, K. Y. C. Lee & J. H. Waite “Mussel-inspired metal-ligand cross-links yield polymer gels with near covalent elastic moduli and self-healing properties” PNAS 2011, 108, 2651-2655. High-throughput characterization of materials on patterned superhydrophobic substrates: a possible platform for combinatorial tests of biological adhesives
Ana I. Neto 1,2 , Catarina A. Custódio 1,2 , Wenlong Song 1,2 and João F. Mano 1,2
1 3B’s Research Group-Biomaterials, Biodegradables and Biomimetics, Department of Polymer Engineering, University of Minho, Portugal 2 IBB – Institute for Biotechnology and Bioengineering, PT Government Associated Laboratory, Guimarães, Portugal
Surface aspects play an essential role in dictating the biological performance of implantable biomedical device or in the development of coatings for a variety of applications, including high-performance biomimetic adhesives. The complete picture of cell biomaterials relationships is far from being understood, due to the existence of inter-dependencies between the different surfaces properties, the influence of the cell type and the complex effect of protein adsorption. High-throughput screening (HTS) approaches permit to correlate the characteristics of materials, surfaces and the biological responses, including cell adhesion and growth in a single experiment. In this study, we describe a novel HTS approach for rapid, microliter-scale deposition of biomaterials and characterization of their interactions with cells based on the use of patterned superhydrophobic surfaces. A mask with hollowed squares was put over the superhydrophobic surface and wettable hydrophilic spots were assessed using UV/Ozone irradiation. The liquid volumes remain confined in regions due to strong contrasts in surface tension, enabling to deposit with high control materials, cells and other substances. The deposition of solutions containing different relative amounts and total concentrations of the human serum albumin and human plasma fibronectin and the binary system were carried out in the developed arrays, in order to understand how cells react when they are previously incubated in solutions containing both kinds of proteins. In the near future, we intend to set-up a HTS strategy to combine different marine-origin or marine-inspired materials, including substances with adhesive properties. Marine inspired bio-adhesives exhibit properties appealing in tissue engineer strategies, including the formation of strong bonds to surfaces in physiological-like environments, and low toxicity.We believe that the new platform developed in this work could be useful in the multiplexing biological and physico-chemical characterization of arrays of different combinations of biological adhesives, with enhanced time and cost effectiveness, in order to produce high performance adhesive coatings for tissue engineering and other biomedical applications.
Biomechanics of adhesion in tree and torrent frogs
Diana Samuel 1, T. Endlein 1, U. Grafe 2, M. Riehle 1 and W.J.P. Barnes 1
1 University of Glasgow, Centre for Cell Engineering, Joseph Black Building, Glasgow, Scotland (UK) 2 Universiti Brunei Darussalam, Faculty of Science (Biology), Brunei (Borneo)
Tree frogs adhere to surfaces using their toe pads. They utilise wet adhesion, which is dependent on 2 forces, capillarity and Stefan adhesion, and is facilitated by the secretion of a fluid from their pads. Since locomotion is a dynamic process, the pads must be able to attach and detach from surfaces repeatedly, an ability that is lacking in man-made adhesives. Furthermore, detachment of the pads should be effortless, so that the frogs do not need to pull their pads from the substrate each time they take a step. We show that they achieve this by peeling, and exhibit other behavioural strategies that enable them to cling onto substrates in challenging conditions, for instance when adhering to overhanging substrates. Torrent frogs also possess expanded toe pads, but live in very wet environments, such as by waterfalls. Such flooded conditions result in their toe pads being submerged, thereby abolishing the air-fluid interface required for capillarity; yet they are still able to adhere to surfaces. This ability could potentially be utilized in the field of biomimetics for a number of applications, such as in the development of more efficient wet-weather car tyres. This poster will aim to show that: (a) detachment of tree frog toe pads is (generally) faster than their attachment, and can occur in a number of ways; (b) compared to torrent frogs, their adhesive ability is drastically reduced on rough, flooded surfaces, thus showing the importance of capillarity; and (c) torrent frogs may have a more specialized toe pad morphology to cope with flooded conditions. Is the adhesive material secreted by sea urchin tube feet species-specific?
Romana Santos 1,2 and Patrick Flammang 1
1 Marine Biology Laboratory, University of Mons-UMONS, Belgium 2 Present address: Unidade de Investigação em Ciências Orais e Biomédicas, Faculdade de Medicina Dentária, Universidade de Lisboa, Portugal
Sea urchin adoral tube feet are highly specialized organs that have evolved to provide efficient attachment to the substratum. They consist of a disc and a stem that together form a functional unit. Tube foot disc tenacity (adhesive force per unit area) and stem mechanical properties (e.g. stiffness) vary between species but are apparently not correlated with sea urchin taxa or habitats. Moreover, ultrastructural studies of sea urchin disc epidermis also pointed out differences in the internal organization of the adhesive secretory granules among species. This prompted us to look for molecular differences in the composition of echinoid adhesive secretions which could explain the variability in disc tenacity and ultrastructure. To address this issue, a comparative immunohistochemical approach was used. Polyclonal antibodies were raised against the footprint material of one species, Sphaerechinus granularis, and used to evaluate interspecific differences in the composition of the contents of tube foot adhesive cells by looking for antibody cross-reactivity on histological sections. Results showed that the produced antisera specifically labeled the adhesive secretory cells of the disc epidermis in the tube feet of S. granularis. Surprisingly, no cross-reactivity was observed on tube foot histological sections from seven other sea urchins species from different taxa and habitats. These results indicate that unlike those of asteroids, echinoid adhesive secretions share very few common epitopes and would thus be “species-specific”. This supports a relationship between the interspecific variations in sea urchin disc tenacity and the composition of their adhesive secretions.
Polyzwitterionic surface: Preparation and properties
Patrik Sobol čiak, Igor Lacík and Peter Kasák
Polymer Institute SAS, Bratislava, Slovak Republic
Polyzwitterions are polymers, which consist from internal salts with positive ammonium and negative sulfo, carboxy or phosphate group in monomer unit [1,2]. The structural and behavioral similarity of polyzwitterions to biopolymers and biomembranes gives access to models materials with biomimetic properties. Surfaces coated with zwitterionic groups assign biomimetic nonadhesive properties mainly due to electrostatic interaction between positive and negative moiety [3]. Idea of zwitterionic surface consists in developing of nonbiofouled zwitterionic surface after irradiation by light. In this contribution we prepare polyzwitterionic surface with polycarboxy and polysulfobetaine moieties via photoimmobilization by means of photolabile azido group. Grafting density and non biofouled properties were evaluated.
This work was supported by the Scientific Grant Agency of the Ministry of Education of Slovak Republic under the Grant VEGA No. 2/0152/10.
References
[1] Lowe A. B., McCormick C. L. Chem. Rev. 2002, 102, 4177-4189. [2] Sobol čiak P., Lacík I., Kasák P. Chem. Papers, 2011, accepted. [3] Chen S., Li L., Zhao Ch. Zheng J. Polymer 2010, 51, 5283-5293. Microscopic morphology and mechanical properties of biomimetic polymer thin films
Thi Chinh Ngo 1, Radostina Kalinova 2, Rosica Mincheva 2, Philippe Dubois 2, Roberto Lazzaroni 1, Philippe Leclère 1
1 Laboratory for Chemistry of Novel Materials 2 Laboratory of Polymeric and Composite Materials Center of Innovation and Research in Materials and Polymers (CIRMAP) University of Mons (UMONS), Belgium
Our research project focuses on studying the adhesion properties of biomimetic polymer surfaces to achieve reversible adhesion on dirty or wet surfaces, but also in aqueous media. For this purpose, we synthesized block copolymers containing a Poly (dimethylsiloxane) (PDMS) segment and a segment of ionogenic poly-(2- dimethylamino) ethyl methacrylate (PDMAEMA) or polyacrylic acid (PAA). The interactions between these ionic segments in aqueous media may participate in the formation of a reversible adhesive as a function of specific and controllable conditions (pH, ionic strength, temperature). These copolymers were synthesized by atom transfer radical polymerization (ATRP). Thin films of those copolymers were prepared by spin coating. To understand the surface morphology and mechanical properties of the copolymer films, we used a new Atomic Force Microscope technique called Peak Force Quantitative Nanomechanic Property Measurements (PFQNM) based on real- time force-distance curve analysis. This allows us to locally measure various nano- scale material properties such as Young's modulus (from data analysis based on the DMT model), adhesion, deformation and dissipation, simultaneously to the height image. Scaffolds made of hydroxyapatite, collagen and chitosan for improved adhesion and bioactivity of osteoblastic cells
Gherghe Tomoaia 1, Olga Soritau 2, Lacrimioara-Bianca Pop 3, Gabriel Furtos 3, Cristina Prejmerean 3, Aurora Mocanu 3 and Maria Tomoaia-Cotisel 3
1 Luliu Hatieganu University of Medicine and Pharmacy, Orthophaedics and Traumatology Department, Cluj-Napoca, Romania 2 Oncologic Institute of Cluj-Napoca, Romania 3 Babes-Bolyai University, Faculty of Chemistry and Chemical Engineering, Physical Chemistry Center, Cluj-Napoca, Romania
In the present study a new strategy of syntheses is developed for silicon substituted hydroxyapatite of controlled properties by precipitation reactions. The resulted powder is characterized by physicochemical methods and used to prepare scaffolds for cell cultures. Further, nanostructured hydroxyapatite (HAP) with or without various Mg, Zn, and SiO2 contents of controlled porosity and crystalinity as well as composite biomaterials formed of HAP nano particles of controlled properties (shape, size and density) mixed with collagen type I (COL), and chitosan (CHI) at different HAP/COL/CHI weight ratios were designed, prepared and in vitro structurally characterized. The hydroxyapatite nano powders, collagen, chitosan and the resulted composite biomaterials were characterized using FTIR, X-ray diffractions, SEM, TEM and AFM. The BET and porosity were also used to analyze their micro-structure and TEM and AFM to analyze their nanostructures. The inorganic nano powder incorporation within collagen and chitosan matrix leads to biocomposites with good mechanical properties, which can be controlled by the HAP/COL/CHI weight ratios. Further, the optical microscopy, scanning electron microscopy and AFM were used to evaluate the behavior of osteoblasts, like MG-63 cells, cultured on scaffolds made of the different mixed inorganic powder/collagen/chitosan self-assemblies for several days. Results showed a good adhesion, growth and proliferation of osteoblasts on the surface of investigated scaffolds, especially when they were made of complex hydroxyapatite and from HAP/COL/CHI biomaterials of at least 20 % COL weight content. These data also demonstrated that the bioactivity of hydroxyapatite can be improved by introducing within its structure Mg, Zn, and SiO2. The data have revealed the high importance of granulation of inorganic powders in the preparation of scaffolds biomaterials of controlled properties with applications in particle technology, pharmacy and nano medicine.
Acknowledgements to COST Action TD0906 Biological adhesives from biology to biomimetics. Suction system inspired to octopus sucker
Francesca Tramacere 1,2 , Lucia Beccai 1, Barbara Mazzolai 1
1 Center for MicroBioRobotics@SSSA; Istituto Italiano di Tecnologia (IIT); Pontedera (Pisa), Italy 2 Biorobotics Institute, Scuola Superiore Sant’Anna, Pontedera (Pisa), Italy
Nature offers many interesting adhesion mechanisms where attachment forces can be generated in a binary on/off state. From an engineering point of view, the study of efficient attachment and detachment mechanisms is extremely interesting and deserves attention for the development of new artificial strategies in robotics. This work describes a preliminary study of an adhesion solution inspired by the octopus suckers, starting by a deep investigation of the biological features that allow octopus to perform a variety of complex movements. We used four different techniques (magnetic resonance imaging, ultrasonography, histology and CryoSem) in order to investigate morphological and anatomical features of the octopus suckers at structure and sub-structure scale. Moreover, sucker 3D reconstructions, both from histological and magnetic resonance images were performed with the aim at obtaining spatial information (physical dimensions, morphological information, spatial arrangement of different tissues, etc.). The 3D reconstructions were used to develop the first sucker mock-ups as well. The final goal is to extract the biological features and physical principles relevant to design and develop innovative bio-inspired adhesion mechanisms. With this in mind, a deep investigation of the natural phenomenon at the basis of this amazing adhesion mechanism in octopus is under progress. Single molecule force spectroscopy as a tool to characterize mechanical properties of biomimetic polymers
Giuliano Greco 1, Marco Faimali 2, Massimo Vassalli 1
1 IBF-CNR, Genova, Italy 2 ISMAR-CNR, Genova, Italy
Single molecule force spectroscopy is a powerful tool, able to characterize the mechanical properties of a model system at different scales, from single molecules to fibers and substrates. The same measurement principle, based on the elastic deflection of an atomic force cantilever, can be exploited to study the adhesion of single molecules to selected surfaces, the mechanical resistance of fibrillar multimers or even the mutual interaction of single cells or organisms. This technique will play a major role in the context of rational design of biomolecules with tailored mechanical properties, and learning from natural proteins will help highlighting the key aspects of such a complex phenomenon. The presented work will start from a case study on a biomimetic elastomeric peptide to extend the conclusions towards a comparative study on biohadesivity.
Lingual adhesion in prey capture by the agamid lizard Pogona vitticeps (Reptilia, Squamata)
Leïla-Nastasia Zghikh 1, Gérard Toubeau 1, Denis Nonclercq1, Alexandre Legrand 2 and Vincent Bels 3
1 Laboratory of Histology - Faculty of Medicine and Pharmacy, University of Mons, Belgium 2 Laboratory of Pharmacology - Faculty of Medicine and Pharmacy, University of Mons, Belgium 3 Muséum National d’Histoire Naturelle – Département d’Ecologie et Gestion de la Biodiversité – UMR 7179 MNHN/CNRS, Paris, France
Lingual prehension is one of the major modes of prey/food capture in Squamates. The tongue is protracted or projected toward the prey, adheres to the prey and retract it into the buccal cavity. As soon as the prey is bitten by the jaws, the transport phase begins. The tongue must loose the contact with the food item to be able to move foward under the prey and retracts the food at each opening-closing cycle of the jaw apparatus. The prey is always contacted by the same papillar area of the foretongue. Here, we present a preliminary study of tongue morphology (histology, SEM) and kinematics to characterise the adhesion between the prey and the tongue in one representative iguanian lizard using lingual prey prehension, Pogona vitticeps . The organisation and histochemical properties of the papilar area of the fore tongue is described. The adhesion forces at prey capture is calculated by using force transducer. SEM is used to show how tongue “stickiness” secretion is in contact with the cuticle of the prey. All these data are used to propose new insight and model for explaining mechanism of adhesion at prey capture in iguanian lizards.