COST Action TD0906 · 2014-10-30 · P6. Doina Prodan, Cristina Prejmerean Gabriel Furtos, Ovidiu Pastrav, Stanca Boboia, Laura Silaghi-Dumitrescu, Violeta Popescu, Marioara Moldovan,

COST Action TD0906

WG3 & WG4 Scientific Workshop

Biological Adhesives: from Biology to Biomimetics

Cluj Napoca, Romania,

9th -11th of April 2013 http://www.cost-bioadhesives.org

WG3 & WG4 Scientific Workshop

Biological Adhesives: from Biology to Biomimetics

9th -11th of April 2013, Cluj Napoca, Romania

Programme overview Tuesday 9th April

Oral sessions, poster session, Management Committee meeting and coffee breaks will be held in conference room from University Guest House of Babes Bolyai University situated in Iuliu Hatieganu Park. Swedish breakfast, lunch, dinner will be at University Guest House restaurant. Generally, invited speakers have 40 minutes slot (aprox 35 minutes talk + 5 min questions) and others they have 30 minutes slot (25'+5'). 08:00 - 09:15 Registration

09:15 - 09:30 Welcome – Opening -Chair. Dr. Patrick Flammang -COST Official

09.30-11.00 Oral communications (Chairman: Dr. Patrick Flammang)

09.30-10.00 Thomas Endlein, W. Jon P. Barnes, Diana Samuel, Niall Crawford, and Ulmar Grafe “Sticking under wet conditions: the remarkable attachment abilities of torrent frogs (Staurois guttatus)”

10.00-10.30 Jagoba Iturri, Aránzazu del Campo “Adhesion and friction of tree- and torrent-frog mimics: the role of surface patterns in reversible wet adhesion”

10.30-11.00 Coffee break

11.00 - 12:00 Oral communications (Chairwoman: Dr. Romana Santos)

11.00 - 11:30 W. Jon P. Barnes, Walter Federle and Thomas Endlein “Adhesion and friction forces generated by single toe pads of the tree frog, Litoria caerulea”

1130 - 12:00 Clemens F. Schaber, Thorsten Heinlein, Jörg J. Schneider, Stanislav N. Gorb “Tribological properties of vertically aligned carbon nanotubes arrays”

12:00 12:00 - 13:00

Group photo in front of hotel Lunch

13:00 - 14:00 Oral communications (Chairman: Dr. Stanislav Gorb)

13:00 - 13:30 Simone Dimartino, David Savory, Luigi Petrone, A. James McQuillan “ATR-FTIR and microscopic study of the attachment of zygotes from the seaweed Durvillaea antarctica”

13:30 - 14:00 Rui R. Costa, Ana I. Neto, Ilker Calgeris, Clara R. Correia, António C. M. Pinho, Jaime Fonseca, Ebru T. Oner and João F. Mano “Layer-by-layer assembly using bacterial Levan adhesive polymer”

14:00-15.00 Coffee break

15.00-16:00 Posters Session P1. M. Demeuldre, R. Wattiez, P. Becker, E. Hennebert & P. Flammang “Sea cucumber Cuvierian tubules: characterization of the adhesive by different approaches” P2. Francesca Tramacere, Lucia Beccai, and Barbara Mazzolai “Adhesion mechanism in Octopus vulgaris” P3. D. Labonte, W. Federle “Heel” pads of stick insects (Carausius morosus) are pressure-sensitive friction pads with little adhesion” P4. Dirk Drotlef, Jiaxi Cui, Jagoba Iturri, Aránzazu del Campo “Tuning adhesion with actuated patterns” P5. Luis García-Fernández, Jiaxi Cui, Cristina Serrano, Zahid Shafiq, Jagoba Iturri Ramos, Aránzazu del Campo “Antibacterial strategies from the sea: polymer bound Cl-catechols for prevention of biofilm formation” P6. Henrik Peisker, Jan Michels, Alexander Filippov, Stanislav Gorb “The beetle in rubber boots: resilin gradient in the adhesive setae of Coccinella septempunctata” P7. Birgit Lengerer, Robert Pjeta, Julia Wunderer, Marcelo Gomez Rodrigues, Willi Salvenmoser, Roberto Arbore, Eugene Berezikov, Lukas Schärer, Peter Ladurner “The adhesive system of the flatworm Macrostomum lignano: a morphological and molecular biology analysis” P8. Robert Pjeta, Julia Wunderer, Birgit Lengerer, Marcelo Rodrigues, Willi Salvenmoser, Roberto Arbore, Eugene Berezikov, Lukas Schärer, Peter Ladurner “Screening for adhesion related genes in the flatworm Macrostomum lignano” P9. Marcelo Rodrigues, Robert Pjeta, Julia Wunderer, Birgit Lengerer, Peter Ladurner “A molecular biology approach in bioadhesion research” P10. A. Maiorana, M. Papi, F. Bugli, R. Torelli, B. Posteraro, V. Palmieri, G. Ciasca, M. Chiarpotto, G. Maulucci, M. De Spirito, M. Sanguinetti. “Adhesive properties of Aspergillus Fumigatus biofilms probed by atomic force microscopy and effects of Alginate Lyase enzyme” P11. Niall Crawford “The adhering abilities of tree frogs on rough surfaces”

16:30 – 18:00

COST Management Committee meeting (Everybody can join but only the Management Committee is allowed to vote)

18:20 – 24:00 Workshop Dinner (Traditional Romanian food at a restaurant in the city) (Taxi in front of hotel)

Wednesday 10th April 08:30 - 09:40 Oral communications (Chairman: Dr. Gabriel Furtos)

08:30 - 09:10 Diego Mantovani “Improving adhesion and stability of nanocoatings for high-performance health applications”(Invited)

09:10 - 09:40 Havazelet Bianco-Peled and Maya Davidovich-Pinhas “Acrylated polymers: a new concept in mucoadhesion”

09:40 -11:50 Coffee break

10:40 – 12 :30 Oral communications (Chairman: Dr. Gabriel Furtos)

10:40 -11:10 Alexandrina Muntean “Evaluation of retention for sealing materials fotoseal and admira

seal”

11:10 -11:50 Ulrich Salz “Adhesive Dentistry, an overview” (Invited)

11:50 - 12:40 Lunch

12:40 – 13:40 Posters Session

P1. Katarzyna Lewandowska, Alina Sionkowska “Structure and rheological properties of chitosan/poly(vinyl alcohol) mixtures as materials designed for biomedical applications” P2. Bogdan Baldea, Gabriel Furtos, Luminita Nica. “ Influence of the root canal filling material on the retentive strength of self adhesive resin cements – an in vitro study”

P3. Klaus Rischka, Anju Brooker “From Lignin to new bio-based polymers” P4. Roxana-Diana Pasca and Daniel Frankel “Interaction of lipids with lectins”

P5. Violeta Pascalău, Violeta Popescu, George Liviu Popescu, Mircea Cristian Dudescu, Gheorghe Borodi, Adrian Dinescu. “The cross-linking influence on the mechanical properties and swelling behaviour of alginate/k-carrageenan hydrogel films” P6. Doina Prodan, Cristina Prejmerean Gabriel Furtos, Ovidiu Pastrav, Stanca Boboia, Laura Silaghi-Dumitrescu, Violeta Popescu, Marioara Moldovan, Radu Silaghi-Dumitrescu, Monica Saplontai “Evaluation of adhesion for two experimental endodontic sealers by push-out test” P7. Stanca Boboia, Marioara Moldovan, Codruta Sarosi, Cristina Prejmerean, Doina Prodan, Laura Silaghi Dumitrescu, Saplontai Viorica, Ioan Ardelean “The structural investigation of 4 experimental biocomposites” P8. Cristina Prejmerean, Tinca Buruiana, Moldovan Moldovan, Gabriel Furtos, Stanca Boboia, Doina Prodan, Laura Silaghi-Dumitrescu, Stanca Boboia, Ioana Hodisan, Loredana Colceriu. “Effect on adhesion to tooth structure of new experimental adhesive systems based on modified polyalchenoic acids” P9. Laura Silaghi Dumitrescu, Doina Prodan, Violeta Popescu,, Cristina Prejmerean, Gabriel Furtos, Stanca Boboia, Codruta Sarosi, Marioara Moldovan. “Analysis of the degradation by SEM and FTIR of experimental composites” P10. Ioana Hodisan, Gabriel Furtos, Tinca Buruiana, Cristina Prejmerean Loredana Colceriu, Maria Tomoaia-Cotisel “Evaluation of microleakage of dental hard tissues/giomer interface” P11. Aniela Saplonţai-Pop, Augustin Moţ, Radu Silaghi Dumitrescu, Corina Ionescu, Marioara Moldovan “Obtaining Allium cepa extracts for medical use“

P12. Ovidiu Pastrav, Laura Silaghi Dumitrescu, Stanca Boboia, Doina Prodan, Aniela Pop, Mihaela Pastrav, Marioara Moldovan “Evaluation of colour changes in composite materials after application of bleaching agents”

P13. Marieta-Adriana Naghiu, Maria Gorea, Maria Tomoaia-Cotisel, Daniel Frankel “Study of mechanical properties of forsterite ceramics using nanoindentation method” P14. Ancuţa Dăniştean, Ana Madalina Budaca, Alexandra Ioana Gog, Aurora Mocanu, Gheorghe Tomoaia, Liviu Dorel Bobos and Maria Tomoaia-Cotisel “Biomaterials made of hydroxyapatite and collagen type 1 with potential apllications in medicine” P15. Valer Almasan, Mihaela D. Lazar, Gheorghe Tomoaia, Aurora Mocanu, Corina Garbo, Laura Ciupeiu, Camelia Ciobotariu, Adriana Andonie, Cristina Spelmezan, Liviu Dorel Bobos and Maria Tomoaia-Cotisel “Modified nanostructured hydroxyapatite with medical applications” P16. Gheorghe Tomoaia, Alexandra-Gertrud Hosu-Prack, Ioan Petean, Aurora Mocanu, Maria Tomoaia-Cotisel “The effect of hydroxyapatite nanoparticles on collagen mineralization” P17. Szabolcs Santa, Csaba-Pal Racz, Maria Tomoaia-Cotisel “Inclusion Mechanism of lipoic acid into cyclodextrin” P18. Julia Syurik, Michael Röhrig, Oleg I. Ilin, Alexandr A. Fedotov, Oleg A. Ageev, Hendrik Hölscher “YCNTs- based Gecko-inspired Adhesion Surfaces”

13:40 – 14:40 Coffee break

14.40 Visit to Salt Salina Turda (Bus in front of hotel)

Thursday 11th April 09:00 - 10:30 Oral communications (Chairwoman: Dr. Marioara Moldovan)

09:00 - 09:30 Petra Ditsche-Kuru, Dylan K. Wainwright and Adam P. Summers “The impact of

fouling on suction adhesion in Northern Clingfish”

09:30 - 10:00 Nisita S. Wanakule, Stéphane Auguste, Dominique Hourdet, Costantino Creton “Adhesion strength and water permeability of adhesives for medical bandages”

10:00 - 10:30 F. Sima, E. Axente, L. E. Sima, U. Tuyel, M. S. Eroglu, N. Serban, C. Ristoscu, S. M. Petrescu, E. Toksoy Oner, I. N. Mihailescu “Bioactive thin film assemblies by Combinatorial Matrix-Assisted Pulsed Laser Evaporation”

10:30 - 11:30 Coffee break

11:30 - 12:00 Closing remarks and future activity

12:00 - 13:00 Lunch

13:00 - 13:30 Goodbye coffee

13:30 Visit to Etnography Museum of Transylvania and city

Draft Agenda Management Committee Meeting

COST Action TD0906

Biological Adhesives: from Biology to Biomimetics Cluj Napoca, Romania, the 9th of April 2013

0. Welcome to participants 1. Adoption of agenda 2. Minutes of last meeting 3. Matters arising (new AO) 4. Report from the COST Office (by Mr Kent Hung)

− 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 for the last year

6.3.1 Location and date of next meetings (including final Action meeting) 6.3.2 Location and date of next training schools

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 (possibility of a follow-up Action?) 14. Closing

Organizing Committee: Dr. Patrick Flammang (Cost Action Chair, Grant Holder, Belgium Delegate in MC) Universit de Mons Laboratoire de Biologie marine, Mons Belgium Dr. Romana Santos (Cost Action Vice Chair, Portuguese Delegate in MC) Biomedical and Oral Sciences Research Unit (UICOB), Faculdade de Medicina Dentria, Universidade de Lisboa Cidade Universitria, Lisboa Portugal Dr. Stanislav Gorb (Cost Action Vice Chair, Leader of WG3 group, Germany Delegate in MC) Christian Albrechts University of Kiel Zoological Institute, Functional Morphology and Biomechanics, Kiel Germany Dr. Aranzazu Del Campo (Cost Action Vice Chair, Leader of WG4 group, Germany Delegate in MC) Max-Planck-Institut fr Polymerforschung Ackermannweg 10 Mainz. Germany Prof. Markus LINDER (Cost Action Vice Chair, Leader of WG1 group, Finland Delegate in MC) Aalto University, Finland Dr Nicholas ALDRED (Cost Action Vice Chair, Leader of WG2 group, UK Delegate in MC) School of Marine Science and Technology, Ridley Building, Newcastle University, UK

Local Organizing Committee:

Dr. Gabriel Furtos (Local Chair)

Dep. of Dental Materials, Raluca Ripan Institute of Research in Chemistry, Romania

Dr. Cristina Prejmerean


Dr. Marioara Moldovan


Professor Maria Tomoaia-Cotisel

Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, Cluj-

Napoca, Romania

Dr. Bogdan Baldea

Dep. of Prosthodontics, Faculty of Dental Medicine, Timisoara, Romania

Participant Name Institution, Country E-mail Antoniac Aurora Polytechnic University of Bucharest, Romania [email protected] Baldea Bogdan University of Medicine and Pharmacy "Victor Babes", Romania [email protected] Barnes Jon Glasgow University, United Kingdom [email protected] Boboia Stanca Babes-Bolyai University - "Raluca Ripan" Institute of Research in

Chemistry, Romania. [email protected] Bobos Liviu-Dorel Babes-Bolyai University, Romania [email protected] Braun Julius Universität Tübingen, Germany [email protected] del Campo Aránzazu Max-Planck-Institut für Polymerforschung, Germany [email protected] Crawford Niall University of Glasgow, Scotland [email protected] Creton Costantino ESPCI ParisTech, France [email protected] Danistean Ancuta Babes-Bolyai University, Romania [email protected] Demeuldre Mélanie University of Mons, Belgium [email protected] Diaconu Gabriela University of the Basque, Spain [email protected] Dimartino Simone University of Canterbury, New Zealand [email protected] Ditsche-Kuru Petra Univ. Kiel and University of Applied Science Bremen, Germany [email protected]

Dumitrescu Silaghi Laura Babes-Bolyai University - "Raluca Ripan" Institute of Research in Chemistry, Romania. [email protected]

Endlein Thomas University of Glasgow, University Avenue, United Kingdom [email protected]

Eraqi Khannoon Institute of Molecular, Cell & Systems Biology, University of Glasgow [email protected]

Flammang Patrick University of Mons, Belgium [email protected] Foreman Paul Henkel Corporation, USA [email protected]

Frenzke Lena Institute for Botany, Technical University, Germany [email protected]

Furtos Gabriel Babes-Bolyai University - "Raluca Ripan" Institute of Research in Chemistry, Romania. [email protected]

Garbo Corina Babes-Bolyai University, Romania [email protected] Gorea Maria Babes-Bolyai University, Romania [email protected] Gorb Stanislav Zoological Institute, Kiel University, Germany [email protected] Goutay Natacha ESPCI ParisTech, France [email protected] Haber Meir Biota Ltd., Israel [email protected] Havazelet Bianco-Peled Israel Institute of Technology, Israel [email protected] Hodisan Ioana Babes-Bolyai University, Romania [email protected] Horovitz Ossi Babes-Bolyai University, Romania [email protected] Hosu-Prack Alexandra-Gertrud

Babes-Bolyai University, Romania [email protected]

Iturri Jagoba Max-Planck Institute for Polymer Research, Germany [email protected] Labonte David University of Cambridge, United Kingdom [email protected] Ladurner Peter University of Innsbruck, Institute of Zoology, Austria [email protected]

Participant Name Institution, Country E-mail Lengerer Birgit University of Innsbruck, Institute of Zoology, Austria [email protected] Lewandowska Katarzyna Nicolaus Copernicus University, Poland [email protected] Lopes Manuela University of Lisbon, Portugal [email protected] Maiorana Alessandro Università Cattolica del Sacro Cuore, Italy [email protected] Mano João F University of Minho, Portugal [email protected] Mantovani Diego Laval University, Canada [email protected] Mocanu Aurora Babes-Bolyai University, Romania [email protected] Moldovan Marioara Babes-Bolyai University - "Raluca Ripan" Institute of Research in

Chemistry, Romania [email protected] Muntean Alexandrina University of Medicine and Pharmacy „Iuliu Hatieganu”, Romania. [email protected] Naghiu Marieta-Adriana Babes-Bolyai University, Romania [email protected] Neto Isabel 3B´s Research Group, Portugal [email protected] Nica Luminita University of Medicine and Pharmacy "Victor Babes", Romania [email protected] Pasca Roxana-Diana Babes-Bolyai University, Romania [email protected] Pascalau Violeta Technical University, Romania [email protected] Pastrav Ovidiu University of Medicine and Pharmacy „Iuliu Hatieganu”, Romania [email protected] Petean Ionel Babes-Bolyai University, Romania [email protected] Pjeta Robert University of Innsbruck, Institute of Zoology, Austria [email protected] Aniela Saplonţai-Pop University of Medicine and Pharmacy „Iuliu Hatieganu”, Romania [email protected] Preiss-Bloom Orahn LifeBond Ltd, Israel [email protected] Popescu Violeta Technical University, Romania [email protected]

Prejmerean Cristina Babes-Bolyai University - "Raluca Ripan" Institute of Research in Chemistry, Romania [email protected]

Prodan Doina Babes-Bolyai University - "Raluca Ripan" Institute of Research in Chemistry, Romania [email protected]

Rischka Klaus Fraunhofer IFAM, Germany [email protected] Rodrigues Marcelo University of Innsbruck, Institute of Zoology, Austria [email protected] Santos Romana University of Lisbon, Portugal [email protected] Salz Ulrich Ivoclar Vivadent AG, Liechtenstein [email protected] Samuel Diana University of Glasgow, Scotland [email protected] Schaber Clemens Zoological Institute, Kiel University, Germany [email protected] Schmitt Christian University Tübingen, Germany [email protected] Syurik Julia Karlsruhe Institute of Technology, Germany [email protected] Szabolcs Santa Babes-Bolyai University, Romania [email protected] Toksoy Oner Ebru Marmara University, Turkey [email protected] Tomer Guy LifeBond Inc., Israel [email protected] Tomoaia-Cotisel Maria Babes-Bolyai University, Romania [email protected] Tramacere Francesca Istituto Italiano di Tecnologia, Italy [email protected] Voigt Dagmar Institute for Botany, Technical University, Germany [email protected] Wunderer Julia University of Innsbruck, Institute of Zoology, Austria [email protected]

ORAL COMMUNICATIONS Tuesday 9th April

STICKING UNDER WET CONDITIONS: THE REMARKABLE ATTACHMENT ABILITIES OF TORRENT FROGS (STAUROIS GUTTATUS)

Thomas Endlein

1, W. Jon P. Barnes

1, Diana Samuel

1, Niall Crawford

1, and Ulmar Grafe2

1Centre for Cell Engineering, Institute for Cell, Molecular and Systems Biology, Joseph Black Building, University Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom

2Kuala Belalong Field Studies Centre, Universiti Brunei Darussalam, Faculty of Science (Biology), Jalan Tungku Link, Gadong BE1410, Brunei Darussalam

Tree frogs climb and adhere to vertical and overhanging smooth surfaces by wet adhesion. Their adhesive toe pads secrete a thin layer of watery mucus that forms a meniscus around the edge of each pad, resulting in capillary forces that provide adhesion through a combination of Laplace pressure and tensile forces. Torrent frogs, on the other hand, live in the neighbourhood of waterfalls, and can be seen climbing on steep wet rock, where the air-fluid interface can be presumed to be disturbed or absent since the toe pads ore often completely submerged in water. This study examines the abilities and underlying adhesive mechanisms of torrent frog adhesion through a comparison of the adhesive capabilities of torrent frogs (Staurois guttatus) and tree frogs (Rhacophorus pardalis) under controlled laboratory conditions. We challenged both frog species to cling on to a platform which could be tilted from the horizontal through a vertical orientation to an upside-down position. We tested the frogs on three different levels of roughness, and three different regimes of water flow. On dry smooth surfaces, both frog species performed well, a high percentage being still attached at 180° (upside-down). However, as the levels of both wetness and roughness increased, the torrent frogs performed significantly better than the tree frogs. For instance, on the roughest surface under flooded conditions (water flow of 4 litres per minute on a surface consisting of 1125µm glass beads), torrent frogs fell from the surface at a median angle of 171°, while tree frogs slipped off at a median angle of only 29°. In an attempt to gain an understanding of the torrent frogs’ remarkable ability to cling to rough, wet surfaces, we have measured the adhesive forces of both single toe pads and small areas of ventral body skin, visualised actual contact area (body as well as pads) at different angles of tilt, and filmed strategies for remaining attached in both species. We have additionally carried out an SEM study of the different surfaces used in adhesion. The results do not provide a comprehensive explanation for the differences in adhesive ability, but the following features clearly contribute. First, in respect of contact area, both species have some of their ventral body surface in contact with the platform at 0° (horizontal). In torrent frogs, contact area tends to increase with angle of tilt, but in tree frogs it declines until, at the highest angles, the tree frogs are adhering by their toe pads alone. Second, torrent frog toe pads can generate higher friction and adhesive forces on smooth, dry surfaces, but force per unit area declines to low levels in both species as both roughness and degree of wetness increase. Together, adhesive stress and contact area measurements account for the difference in performance, but do not explain it. The explanation may be partly due to climbing ability, the torrent frogs seemed to be better able to manoeuvre on steep surfaces without permanently losing body contact than the tree frogs. Finally, the microstructure of the pads of the torrent frogs showed adaptations (straighter channels between the epithelial cells especially at the margins of the toe pad) that would promote more rapid draining of excess fluid from the pad surface. However, the nature of the forces used under flooded conditions remains elusive. Since capillarity effects will be small under flooded conditions, the dominant forces that provide torrent frogs with their remarkable abilities are likely to be hydrodynamic. However, positive evidence for significant hydrodynamic forces is currently lacking.

ADHESION AND FRICTION OF TREE- AND TORRENT-FROG MIMICS: THE ROLE

OF SURFACE PATTERNS IN REVERSIBLE WET ADHESION

Jagoba Iturri, Aránzazu del Campo

Max-Planck-Institut für Polymerforschung

Ackermannweg 10, 55128 Mainz, Germany

Tree and torrent frogs are able to adhere and walk onto wet or even flooded surfaces. The

complex hierarchical superstructure of their attachment pads, containing soft micro and

nanopillars separated by narrow channels of defined dimensions, and a fluid secretion are the

keys for the special adhesion performance. We have fabricated artificial mimics of the frog

attachment structures and we will report on the role of pattern geometry and material properties in

adhesion and friction performance under different scenarios.

ADHESION AND FRICTION FORCES GENERATED BY SINGLE TOE PADS OF THE

TREE FROG, LITORIA CAERULEA

W. Jon P. Barnes, Walter Federle and Thomas Endlein

Glasgow and Cambridge. UK

Tree frogs are thought to adhere by wet adhesion, using forces generated by the mucus that forms

a fluid joint between pad and substrate. Using a two-dimensional force plate, we have recorded

normal and shear forces from single toe pads of White’s tree frog (Litoria caerulea). In particular,

we have investigated the extent to which adhesive forces depend upon capillarity and whether

shear forces depend on actual contact between pad epithelium and substrate.

In all trials, adhesive forces fell to low levels (<0.5mN) when the toe pad was surrounded by a

water drop, which was observed to abolish the meniscus that bounds the toe pad and generates the

capillarity forces (n = 14). Without a water drop, adhesive forces could exceed 5mN (ca 1mN

mm-2). The question arises as to whether this reduction in adhesive force is due to the absence of

the meniscus or whether it results from an increase in pad/substrate distance. Although it is not

possible to estimate pad/substrate distance during force measurements, we were able to repeat the

procedure and observe the effects using interference reflection microscopy, which measures the

thickness of a fluid layer. We observed that the addition of a water drop resulted in a permanent

increase in pad/substrate distance in 25% of cases, a temporary increase in 45% and no change in

30% (n = 40). It can thus be assumed that there were a substantial proportion of cases where the

sharp fall in adhesive force could not be explained by an increase in pad/substrate distance. It is

therefore reasonable to conclude that the loss of the meniscus is the critical feature, demonstrating

the dominant role of capillarity in tree frog adhesion.

Static friction was evident from the build-up of shear force at the onset of sliding, and from the

presence of a remaining shear force 2 min after sliding stopped. It is inconsistent with the

presence of a continuous fluid film between the pad and substrate, but whether it is due to actual

contact or a very thin mucus layer behaving like a solid because of molecular ordering due to

confinement remains to be ascertained. These experiments thus confirm capillarity as the

dominant component of forces normal to the surface, but demonstrate that boundary friction will

play an important role in the prevention of sliding.

TRIBOLOGICAL PROPERTIES OF VERTICALLY ALIGNED CARBON NANOTUBES

ARRAYS

Clemens F. Schaber1, Thorsten Heinlein2, Jörg J. Schneider2, Stanislav N. Gorb1

1 Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Kiel, Germany 2 Technische Universität Darmstadt, Fachbereich Chemie, Eduard-Zintl-Institut für Anorganische

und Physikalische Chemie, Darmstadt, Germany

Carbon nanotubes (CNTs) are a promising material for the fabrication of biomimetic dry

adhesives. The dimensions, and presumably the contact areas, of single CNTs are in the range of

the terminal elements of biological dry hairy adhesion systems, such as the spatulae on the toe of

the gecko.

Densely packed arrays of vertically aligned and up to 1.1 mm long multi-walled CNTs were

synthesized by chemical vapor deposition (CVD). Their tribological properties were tested using

the force tester Basalt-01 in friction mode. Under microscopic conditions, the coefficient of

friction µ was as high as 5 - 6 at the first sliding cycle, and decreased steadily down to values

between 2 and 3 at the fourth to fifth sliding cycles. Such high values of µ can only be explained

by the strong contribution of adhesion. At further loading no significant decrease was measured.

After the tests, clear friction marks were observed on the surface of the specimens. These

wear-induced deformations of the CNT arrays strongly depended on the amount of normal force

applied during the friction experiments. At normal loads in the milli-Newton range, the friction

marks were large clusters of CNTs divided by up to 100 µm wide cracks in the surface. The

clusters and cracks were aligned orthogonally to the direction of sliding. At normal loads in the

micro-Newton range, the largest cracks were 20 µm wide, and CNT clusters were of about 1 µm

in diameter.

Interestingly, the plastic deformation of the CNT arrays does not significantly affect the

coefficients of friction µ after a preconditioning by five sliding cycles. However, a strong

decrease of µ during the initial wear cycles has to be taken into account for the development of

applications, such as non-slip surfaces and pick-and-place techniques for manufacturing.

ATR-FTIR AND MICROSCOPIC STUDY OF THE ATTACHMENT OF ZYGOTES

FROM THE SEAWEED DURVILLAEA ANTARCTICA

Simone Dimartino1, David Savory2, Luigi Petrone3, A. James McQuillan2

1Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand

2Department of Chemistry, University of Otago, Dunedin, New Zealand 3Divisions of Molecular Physics and Integrative Regenerative Medicine Centre,

Department of Physics, Chemistry and Biology, Linköping University, Sweden

Classical adhesives are limited by a number of drawbacks such as poor biodegradability, inadequate performance in wet environments and low applicability to biological systems. Adhesives inspired by marine organisms such as seaweed can overcome these limitations and address new perspectives in biomedical and biosensor applications. However, adhesives produced by seaweed are not well characterized and contradicting results are reported in the literature. Durvillaea antarctica has been chosen as an ideal candidate to shed light on the functionalities responsible for surface attachment of seaweed. In fact, D. antarctica is distinguished from other less developed benthic algae because of the presence of male and female plants which, during their reproductive season, release aploid gametes. When the egg is fertilized by a sperm a diploid zygote containing all genetic information is formed, i.e. the first cell of a new developing plant. Immediate surface attachment is of paramount importance for the newly formed zygote to ensure its survival in the marine environment, therefore secretion of the glue is one of the first processes triggered after fecundation. Attenuated Total Reflection - Fourier Transform Infrared (ATR-FTIR) spectroscopy is a non-invasive and in situ technique that allows the detection of chemical functional groups, conformational changes and adsorption reactions in the proximity of a surface. The ability to run experiments in aqueous environments constitutes a major advantage of this method as physiological conditions similar to that of the natural environment are easily attainable. In order to investigate the components of the bio-adhesive produced by D. antarctica plants, ATR-FTIR adhesion experiments have been performed with fresh eggs and sperm as well as with fertilized zygotes using filtered seawater as the aqueous medium. A comparative analysis of the spectra obtained from the sexual gametes and the fertilized zygotes will be presented, addressing new information on the functional groups involved in zygote attachment. In order to obtain additional information on the changes occurring after fertilization, the evolution of the attaching zygote has been observed using optical microscopy and SEM. The morphology of the adhesive pad and the characteristics of the vesicles bearing the adhesive ingredients will be pointed out. The various results collected will be discussed and new conclusions on the formulation of the glue produced by seaweed will be put forth.

LAYER-BY-LAYER ASSEMBLY USING BACTERIAL LEVAN ADHESIVE POLYMER

Rui R. Costa,a,b Ana I. Neto,a,b* Ilker Calgeris,c Clara R. Correia,a,b António C. M. Pinho,d Jaime

Fonseca,e Ebru T. Oner c and João F. Manoa,b

*email: [email protected]

a 3B´s Research Group - Biomaterials, Biodegradables and Biomimetics, University of Minho,

AvePark, 4806-90 Taipas, Guimarães, Portugal b ICVS/3B´sPT Government Associate Laboratory, Braga/Guimarães, Portugal

c Marmara University, Department of Bioengineering, 34722, Istanbul, Turkey. d University of Minho, Department of Mechanical Engineering, Campus de Azurém, Guimarães,

Portugal. e University of Minho, Department of Industrial Electronics, Campus de Azurém, Guimarães,

Portugal.

Nanostructured coatings consisting of chitosan and the adhesive bacterial exopolysaccharide

levan were fabricated using layer-by-layer (LbL) assembly. Taking advantage of the electrostatic

self-assembly mechanism of LbL, the charges of both chitosan and a phosphonate-derivatized

levan (Ph-levan) were measured and the feasibility to construct hybrid films was monitored and

confirmed using a quartz crystal microbalance with dissipation monitoring (QCM-D). The

adhesive properties between two identical bonded films with a total of 100 layers were compared

to control films in which Ph-levan was replaced by alginate, revealing that the detachment force

of the former is about 3 times higher than the control. Scanning electron microscopy of the films

surface showed that the surface of Ph-levan films is smooth and homogeneous. Cell adhesion

tests were conducted using a L929 cell line. Early cell adhesion is significantly higher in

chitosan/Ph-levan films when compared to chitosan/alginate controls. These findings establish

levan derivatives as bioinspired ingredients for conceiving medical adhesive devices that allow

achieving enhanced mechanical and biological performance. In the context of biomedical and

tissue engineering, these films could provide enhanced adhesiveness and protection to a new

generation of wound healing bandages or to surgical sealants and also surfaces with optimized

cell/substrate interactions, fabricated by a versatile and cost-effective multilayer technology.

THE IMPACT OF FOULING ON SUCTION ADHESION IN NORTHERN CLINGFISH

Petra Ditsche-Kuru1,2,3, Dylan K. Wainwright1,4 and Adam P. Summers1

1University of Washington, Friday Harbor Laboratories, WA, 98350 USA 2Department of Functional Morphology and Biomechanics, Zoological Institute of the University

of Kiel, 24098 Kiel, Germany 3University of Applied Science, Biomimetics-Innovation-Centre, Bremen, Germany

4Duke University, Durham, NC, 27708, USA In aquatic environments solid substrates are fouled by bacteria, algae and invertebrates. Already

after a few hours a biofilm starts to form, later macro fouling organisms can follow. The growth

of all fouling organisms changes the surface properties of the primary substrate considerably and,

thus, the attachment conditions for benthic organisms. For mobile animals, to our knowledge, just

very little is known about this impact of fouling on attachment. In this study, we investigate the

influence of fouling on the adhesive strength of Northern clingfish. This little tidal fish lives

beside the stones and has the remarkable ability to adhere to various kinds of surfaces by its

suction disk. For the experiments we choose four substrates of different kind of surface roughness.

After six weeks exposure in the Pacific Sea, biofilm and periphyton covered the test substrates.

We measured the adhesive force of the fish with a mechanical testing machine on the unfouled

and fouled substrates of each roughness type. On smooth substrates, tenacity was the same on

fouled and unfouled substrates. In contrast, on the rough substrates the tenacity decreased on

fouled surfaces in comparison to the unfouled ones. All fouled surfaces as well as the unfouled

smooth surface show tenacities in the same range. We hypothesize, that substances of the biofilm

act like a lubricant and by this decrease friction of the disk margin, which slides to the disk centre

when the fish is pulled upwards. Nevertheless, even on the fouled surfaces the adhesive forces of

the ventral suction disk are about 150 times higher than the body weight of the fish.

ORAL COMMUNICATIONS Wednesday 10th April

YCNTS- BASED GECKO-INSPIRED ADHESION SURFACES

Julia Syurika, Michael Röhriga, Oleg I. Ilinb, Alexandr A. Fedotovb, Oleg A. Ageevb, Hendrik Hölschera

aInstitute of Microstructure Technology (IMT), Karlsruhe Institute of Technology (KIT),

Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany bCollege of Electronics and Electronic Equipment Engineering, Southern Federal University

(SFU), Nekrasovsky, 44, Taganrog, Russia

Carbon nanotubes (CNTs) are well investigated structures for Gecko-inspired adhesive materials due to their high aspect ratio and exceptional mechanical strength. From studies of gecko’s feet it is known that hierarchy is favorable for the compliance and, therefore, adhesive properties. It was also proven during synthesis of polymer-based gecko-like structures. [1]. Here, we present gecko-inspired hierarchical CNTs. Hierarchical array of “Y”-shaped CNTs (YCNTs) has been produced, providing an opportunity for the investigation of CNTs-based adhesive structures looking just like Gecko’s one (see Fig. 1 and 2). Firstly, a vertically oriented array of CNTs was produced via chemical vapor deposition. Secondly, it was functionalized by ion-beam in the presence of tungsten. As a result, the replacement of the source catalytic metal, which was located in the peaks of CNTs, from Ni to W was made alongside with the splitting of each CNT in two smaller tubes. The subsequent analysis showed that the diameter of the smallest tubes was about 10 nm with a height of 180 nm. For the “main” CNTs arrays diameter and height were about 40 nm and 1 um, respectively.

Figure 1 – SEM image of nanoscale ends of gecko foot hair. Reproduced from [2]

Figure 2 – SEM image of YCNTs [3]

[1] M. Röhrig, M. Thiel, M. Worgull, H. Hölscher. 3D Direct Laser Writing of Nano- and Microstructured Hierarchical Gecko-Mimicking Surfaces. Small (2012) 8, 3009–3015. [2] H.E. Jeong, K.Y. Suh. Nanohairs and nanotubes: Efficient structural elements for gecko-inspired artificial dry adhesives. Nano Today (2009) 4, 335—346. [3] Ageev O.A., Fedotov A.A., Ilin O.I., Klimin V.S. Investigation on modes of hybrid nanostructures formation. Proc. of “Nano and Giga Challenges in Electronics, Photonics and Renewable Energy” Symposium and Summer School, Moscow - Zelenograd, Russia (September 12-16, 2011), 72.

IMPROVING ADHESION AND STABILITY OF NANOCOATINGS FOR HIGH-

PERFORMANCE HEALTH APPLICATIONS

Diego Mantovani, PhD, FBSE

Laboratory for Biomaterials and Bioengineering Canada Research Chair I in Biomaterials and Bioengineering for the Innovation in Surgery Dept of Min-Met-Materials Engineering & Research Center, Quebec University Hospital

Laval University, Québec City, Canada [email protected]

www.lbb.ulaval.ca The adhesion and the stability of nano-coatings (thickness less than 100 nm) are a major concern,

and a recognised main challenge in health. In one hand, nano-coatings bring functionalities and

provide unconventional properties to devices, tools and medical technologies. In the other hand,

the assessment of the adhesion of nano-coatings onto metallic or polymeric substrates is not

trivial, especially in reason of their low thickness. In this talk, two distinct but complementary

applications will be targeted. First, how to improve the adhesion and stability of functional nano-

coatings for medical devices will be addressed. The main clinical complications for current

biomaterials and artificial organs still reside in an interfacial mismatch between the synthetic

surface and the natural living tissue surrounding it. Today, nanotechnology, nanomaterials and

surface modifications provides a new insight to the current problem of biomaterial failures, and

even allows us to envisage strategies for the organ shortage. Advanced tools and new paths

towards the development of functional solutions for cardiovascular clinical applications are now

available. This talk will focus on highly-adherent and strongly-cohesive (after deployment)

fluorocarbon bio-mimicking coatings nano-coatings for intravascular stents. Second, the adhesion

and stability of antibacterial surfaces resisting cycles of cleaning and sterilization will be

presented. Nosocomial infections are a major issue in hospitals, healthcare service units and

generally closed and crowded environments. Antibacterial diamond-like carbon (DLC) coatings

satisfy many of the requirements needed, also exhibit a low surface energy, a low surface

roughness and an excellent corrosion resistance thus being an ideal candidate for such

applications. Several ex situ and in situ interface modification strategies aimed at increasing the

adhesion of DLC to metal substrates will be discussed. The intrinsic goal of this talk is to present

an extremely personal look at how materials, surfaces and interfaces as well as surface

modifications for metals and polymers have progressed, from the glory days of their introduction,

to the promising future that nanotechnology may or may not hold for improving the quality of the

life of millions worldwide.

EVALUATION OF RETENTION FOR SEALING MATERIALS FOTOSEAL AND

ADMIRA SEAL

Alexandrina Muntean

Pediatric Dentistry Department, Faculty of Dental Medicine, University of Medicine and

Pharmacy, ″I.Haţieganu″, Cluj-Napoca, Romania.

Aim. Dental decay represents a major oral health concern in children in our country despite

progress of preventive methods. Sealing pit and fissures, specific method of decay prevention on

occlusal surfaces, appear to be not adequately applied in every day practice mainly because the

insufficient retention of sealing material. The purpose of this study was to assess the retention for

two sealing materials Fotoseal® and Admira Seal® employed under standard condition in a

paediatric dental office.

Material and method. The study was conducted over a period of three years for a number of 234

children’s. First permanent molars free of cavities were sealed using two light cured composite

sealing materials. The two groups of children’s were named using the sealing material

commercial nomination as follows: Group Fotoseal - sealing material used -Fotoseal®- was

designed by the Research Institute of Chemistry"Raluca Ripan" Cluj Napoca and produced by SC

Remed Prodimpex Ltd Bucharest. Number of children’s comprised in this group was 122 at

baseline respectively 110 at the end of the study. Group Admira - sealing material used was

Admira Seal® (VOCO). Number of children’s count up in this group was 112 at baseline and 97

at the end of the study.

Sealing materials were applied in agreement with the category of dental materials and

manufacturer's recommendations. The data obtained every 12 month were processed statistically

using specific programs.

Results. For dental sealant Fotoseal ® immediate retention was 100% and the average percentage

retention after 3 years was 73.97%.For Admira Seal® immediate retention was 100% and the

average percentage retention after 3 years was 78.57%. Re-sealing manoeuvres revealed variation

dependent on the used material, patient gender and tooth specific morphologic and topographic

characteristics.

Conclusions. Maxillary molars perform better for both evaluated sealants compared with

mandibular molars. Retention values obtained in standard condition of dental practice permit us

to encourage dental sealants use. Fotoseal® reveals an adequate retention compared with a

product already on the market offering to paediatric dentists a supplementary alternative.

ADHESIVE DENTISTRY, AN OVERVIEW

Ulrich Salz

Ivoclar Vivadent AG, Bendererstr. 2, FL-9494 Schaan

Liechtenstein

The longevity and success of modern dental restorations very often relies on potent dental

adhesives to provide durable bonds between the dental hard substance, the composite luting

material respectively the restorative composite and in the case of indirect restorations the indirect

restorative material. Due to the complexity of the materials involved a combination of different

bonding mechanism is demanded. To predict clinical outcome of such restorative treatment, a

large variety of in-vitro laboratory tests and clinical in-vivo experiments have been devised,

investigated and published. Biomimetic approaches up till now have failed to improve adhesive

dentistry. The purpose of this review is to provide a current overview of bonding mechanism, the

chemistry behind adhesive dentistry, bond strength testing methods and their applicability to the

characterisation of dental adhesives.

ACRYLATED POLYMERS: A NEW CONCEPT IN MUCOADHESION

Havazelet Bianco-Peled and Maya Davidovich-Pinhas

Technion – Israel Institute of Technology, Israel

Mucoadhesion is a specific form of bioadhesion. It is commonly defined as adhesion events between two materials, at least one of which is a mucosal surface. The mucosa gel layer is a secretion created in specialized epithelial cells lining organs which are exposed to the outer surface of the body yet are not covered with skin. Mucus is composed primarily of water (~95%), but also contains small amounts of salts, lipids, and proteins. The main components responsible for the elastic gel-like structure of the mucus are high molecular weight glycoproteins termed mucins. These molecules can form electrostatic, hydrophobic, sulfide and H-bonding interactions with other substances, a process which potentially leads to mucoadhesion. Transmucosal drug delivery involves transport of therapeutic agents through the mucosa. This method of delivery offers several potential benefits over oral drug administration including relatively rapid uptake of a drug into the systemic circulation and enhanced bioavailability. Mucoadhesion enhances the performance of transmucosal delivery systems by providing extended residence time of the drug at the site of application. Alginate is a linear, water-soluble polysaccharide of 41→ linked α-L-guluronic acid (G) and β-D-mannuronic acid (M) isolated from brown algae. This anionic biopolymer is used in many pharmaceutical and biotechnological applications. Gelation of alginate is based on its affinity toward certain multivalent cations such as Ca+2 and its ability to bind those ions selectively and cooperatively, a process which leads to the formation of ionically or physically cross linked alginate gel. Alginate is also known to display mucoadhesive properties due to its ability to create hydrogen bonds with mucin type glycoproteins through carboxyl-hydroxyl interactions. We propose a new approach based on modification of alginates as a way to enhance mucoadhesion. Michael type addition reaction is used to covalently attach polymers bearing unsaturated acrylate side groups to the mucus. Our studies involved synthesizing a novel biomaterial consisting of PEG-acrylate attached to an alginate backbone. Such a polymer combines the gelation ability of alginate with the mucoadhesion properties arising from the PEG’s characteristics and the acrylate functionality. We have demonstrated a significant improve in adhesion, and characterized the thermal, structural and mechanical properties of the new polymer using differential scanning calorimetry (DSC), thermal gravimetry analysis (TGA), small angle X-ray scattering (SAXS) and rheology measurements. Lack of toxicity was verified using viability assay. This approach opens the way for the design of a new class of mucoadhesive materials.

ORAL COMMUNICATIONS Thursday 11th April

ADHESION STRENGTH AND WATER PERMEABILITY OF ADHESIVES FOR MEDICAL BANDAGES

Nisita S. Wanakule1, Stéphane Auguste2, Dominique Hourdet1, Costantino Creton1

1 Laboratoire de Physico-chimie des Polymères et des Milieux Dispersés, ESPCI ParisTech, Paris,

France 2Urgo Laboratories, Dijon, France

[email protected] Many medical bandages and wound-dressings are made from pressure sensitive adhesives (PSAs) supported by a thin backing.1-3 A common problem of adhesives for this application stems from the fact that PSAs are typically comprised of hydrophobic polymers with negligible permeability to water. When a person sweats, the water becomes trapped between the bandage and the skin, decreasing the adhesive strength and promoting infections.4 It is clear that good water permeability, as much as good and stable adhesion to skin, is an important property of medical bandages. It has been found that the addition of hydrophilic polymer particles, such as carboxymethyl cellulose (CMC), into the hydrophobic PSA helps relieve these problems by increasing the permeability of the material. CMC is a good candidate to be incorporated into the PSAs due to its high water solubility, biocompatibility, and industrial availability. Increasing the amount of CMC in the PSA leads to a much higher water permeability. However, the increase of non-adhesive materials softens the material and can create a weak boundary layer over time, which decreases the adhesion strength of the PSA. Here we present our results on the effect of varying the CMC concentration in the PSA on water absorption, permeability, and adhesion strength. We have measured water permeability, water absorption, and adhesion strength of PSAs containing CMC. Increasing CMC content increases the water permeability rate and water absorption rate. However, it was also observed that absorbed water in the samples decreases the adhesion strength of the material, which is heightened with increasing CMC content. We find that the minimum amount of CMC required to form a percolating hydrophilic path through the adhesives and allow high water permeability occurs between 15% and 20% CMC by weight. We also show that high permeability in this system requires a large amount of water to be absorbed. Furthermore, a slow introduction of water at the interface reveals that samples with no CMC particles drastically decrease their adhesion strength whereas samples with CMC do not. This was attributed to the formation of a water boundary layer at the interface. The magnitude of the water flux to the interface is an important factor in the effect of water to adhesive properties. Our studies identify the important parameters influencing adhesion strength of CMC-filled PSAs whicha re model materials for wound dressing applications.

BIOACTIVE THIN FILM ASSEMBLIES BY COMBINATORIAL MATRIX-ASSISTED

PULSED LASER EVAPORATION

F. Sima1, E. Axente1, L. E. Sima2, U. Tuyel3, M. S. Eroglu4,5, N. Serban1, C. Ristoscu1, S. M.

Petrescu2, E. Toksoy Oner3, and I. N. Mihailescu1

1Lasers Department, National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor

Street, Magurele, Ilfov, RO-77125, Romania 2Institute of Biochemistry of Romanian Academy, Splaiul Independentei 296, Bucharest,

Romania 3Department of Bioengineering and 4Department of Chemical Engineering, Marmara University,

Goztepe 34722 Istanbul, Turkey 5TUBITAK-UME, Chemistry Group Laboratories, 41471 Gebze, Kocaeli, Turkey

Combinatorial organic chemistry is a field which revolutionized the drug industry by the capacity

to combine different innovative materials and biological entities. Here we introduce a new

combinatorial approach for the fabrication of mixed organic thin films. Nanostructures with

compositional gradient could be obtained under control by the simultaneous laser irradiation and

vaporization of two targets. The synchronized matrix-assisted pulsed laser evaporation (MAPLE)

of levan polysaccharide and its aldehyde activated form were used as cryogenic targets for testing

the transfer and assembling of a two-compound biopolymer thin film 1,2. The goal was to rapidly

generate a compositional library of the two polymers with specific properties, in a single-step

process, in order to select an optimum dosage with emphasis on medical application. The gradient

of film composition and structure was demonstrated by infrared spectroscopy and fluorescence

studies while in vitro cell culture assays evidenced characteristic responses of cells to specific

surface regions. The new combinatorial method is able to rapidly generate discrete areas of new

organic thin film compositions with optimized properties than starting materials.

1. Sima, F.; Mutlu, E. C.; Eroglu, M. S. ; Sima, L.E.; Serban, N.; Ristoscu, C. ; Petrescu, S.

M. ; Oner, E.T. ; Mihailescu, I.N. Biomacromolecules. 2011, 12, 2251–2256.

2. Sima F.; Axente E.; Sima L.E; Tuyel U.; Eroglu M.S.; Serban N.; Ristoscu C.; Petrescu

S.M.; Oner E.T.;Mihailescu I.N. Applied Physics Letters. 2012, 101, 233-705.

POSTERS Tuesday 9th April

SEA CUCUMBER CUVIERIAN TUBULES: CHARACTERIZATION OF THE

ADHESIVE BY DIFFERENT APPROACHES

M. Demeuldre1, R. Wattiez2, P. Becker1, E. Hennebert1 & P. Flammang1

1 University of Mons - UMONS, Institute for Biosciences, Biology of Marine Organisms and

Biomimetics, Mons, Belgium 2 University of Mons - UMONS, Institute for Biosciences, Proteomics and Microbiology, Mons,

Belgium

Marine bioadhesive research has been gaining increasing interest because of its high potential for the development of novel adhesives for technological applications in wet environment where “classical glues” cannot operate. Surgery and dentistry are generally pointed out as the fields in which bio-inspired adhesives could be used. Currently permanent adhesion is the most investigated type of adhesion but in the search for new biological models, we are studying Cuvierian tubules, a specialized defense system occurring in some species of sea cucumbers. The material secreted by theses tubules has the particularity to be immediately sticky, hence its classification into the type instantaneous adhesion. When a sea cucumber is stressed, it expels 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 an inorganic fraction accounting for 10% of the dry weight and an organic fraction made up of 36% neutral carbohydrates and 54% proteins. Different methods were used to characterize further the adhesive produced by Cuvierian tubules. Firstly, glue prints left on different surfaces types (glass, mica and teflon) were observed using SEM and the adhesive appeared to be made up of globular nanostructures deposited as a thin film. Secondly, proteins were extracted from glue prints following 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 by electrophoresis and enzymatic digestion, the extracted proteins were analysed by tandem mass spectrometry with the goal of finding some new adhesives proteins. The automatic analyses of the results revealed the presence of several intracellular proteins but also of a few potentially interesting proteins sharing similarities with keratin or casein. Thirdly, a random screening was performed on a Cuvierian tubules cDNA library. Fifty clones were sequenced highlighting two interesting results: (i) one sequence rich in proline and glutamine and (ii) a second sequence related to fibrinogen, a molecule responsible for blood coagulation. Finally, based on the detection of protein post-translational modifications on tubule sections, Western blots were performed to identify the presence of phosphorylated residues and oligosaccharidic structures in proteins.

ADHESION MECHANISM IN OCTOPUS VULGARIS

Francesca Tramacere1,2,*, Lucia Beccai2, and Barbara Mazzolai2

1BioRobotics Institute, Scuola Superiore Sant’Anna, Pisa, Italy 2Center for Micro-BioRobotics@SSSA, Istituto Italiano di Tecnologia, Pontedera, Italy

{francesca.tramacere,lucia.beccai,barbara.mazzolai}@iit.it Abstract. The octopus sucker is a fascinating natural system that can adhere to different substrates and terrains. Octopuses use their suckers to perform a remarkable variety of functions [1], such as, anchoring the body to the substrate, grasping, manipulating and investigating objects. Despite several studies on this topic, spanning more than 100 years, many questions relating the function of the sucker remained unclear. Girod [2] proposed that the octopus sucker attaches to substrates by crushing the entire acetabular chamber, thus implying a sustained attachment by means of the void created by the entire collapsed structure. This explanation was criticised several times, as by Guerin [3], who considered it imprecise and contradictory. Later, Kier and Smith in their model described a sucker that, initially, attaches to a substratum by forming a seal (preventing water from leaking at the rim) and, then, performs suction to maintain adhesion (by reducing the pressure in the acetabular cavity). The authors highlighted that several aspects of the adhesion mechanism need to be investigated by increasing the knowledge of the morphology and the functionality of the structures of the octopus sucker [4]. Our work contributes to this scientific discussion by investigating the morphology and functionality of the adhesion mechanism of Octopus vulgaris suckers. Based on our morphological findings (from histology, magnetic resonance imaging and ultrasonography) [5], we propose a novel hypothesis for the sucker adhesion mechanism. We hypothesize that the octopus performs adhesion by following four stages: (i) the infundibulum makes a seal with the substrate (as already described in [4,6]); (ii) the acetabular radial muscles perform suction (as already described in [4,6]); (iii) at this stage, in our hypothesis, the acetabular meridional muscles contract causing the orifice, between acetabulum and infundibulum portions, to be sealed via the acetabular protuberance; and, finally, (iv) adhesion is kept through preservation of the sucker configuration described in (iii). This way, the octopus is able to perform adhesion over long-time periods with minimal energy consumption. In vivo ultrasonographic recordings, showing the sucker in action, support our adhesion hypothesis. This new understanding of such natural physical mechanism offers revolutionary cues for developing bioinspired artificial adhesion systems. Furthermore, this work presents a useful approach towards investigating potential differences in ecology and performance of sucker adhesion by different species. References 1. Packard A (1988) The skin of cephalopods (Coleoids): general and special adaptations. In: Trueman ER, Clarke MR, editors. The Mollusca, Vol 11 Form and Function. 11 ed. San Diego: Academic Press. pp. 37-67. 2. Girod P (1884) Recherches sur la peau des céphalopodes. La ventouse. Arch Zool Exp. pp. 379-401. 3. Guérin J (1908) Contribution à l'étude des systèmes cutané, musculaire et nerveux de l'appareil tentaculaire des cèphalopodes. Archives of Zoological Experimental Genetics 38: 1-178. 4. Kier WM, Smith AM (1990) The Morphology and Mechanics of Octopus Suckers. Biological Bulletin 178: 126-136. 5. Tramacere F, Beccai L, Kuba M, Mazzolai B (2013) The Morphology and Adhesion Mechanism of Octopus vulgaris suckers. PLOS ONE. submitted 6. Kier WM, Smith AM (2002) The Structure and Adhesive Mechanism of Octopus Suckers. Integr Comp Biol 42: 1146-1153.

“HEEL” PADS OF STICK INSECTS (CARAUSIUS MOROSUS) ARE PRESSURE-

SENSITIVE FRICTION PADS WITH LITTLE ADHESION

D. Labonte & W. Federle

Department of Zoology, University of Cambridge, Cambridge, UK

Many insects possess attachment pads on their feet that enable them to climb on various surfaces.

Indian stick insects (Carausius morosus) have two distinct types of pads on each leg, tarsal “heel”

pads (euplantulae) and a pre-tarsal “toe” pad (arolium). Here we show that euplantulae are

specialised “friction pads”. Single-pad force measurements showed that the friction force of

euplantulae increased with normal load, while adhesion remained small in relation to body weight.

This load-dependence is based on micron-sized microtrichia covering the surface of the

euplantulae. Reflected-light microscopy revealed that both higher normal load and higher shear

forces increased the number of microtrichia in contact, and caused some individual microtrichia

to change from tip to side contact. Both mechanisms are reversible, increasing the real contact

area of the pad and thus its shear resistance under load, but causing only little adhesion, as the

elastic energy stored in the deformed microtrichia helps to break contacts during detachment. As

a result, euplantulae showed high friction coefficients (> 1), despite low macroscopic adhesion.

Our results show that stick insect friction pads produce high traction when pressed against the

substrate, but at the same time allow effortless detachment.

TUNING ADHESION WITH ACTUATED PATTERNS

Dirk Drotlef, Jiaxi Cui, Jagoba Iturri, Aránzazu del Campo

Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz, Germany

Geckos, spiders, frogs and other species have attachment pads with distinct surface patterns. They

allow them to firmly but reversibly attach to surfaces with different roughness and under different

conditions. Changes in the topography of their attachment pads are crucial for this on-demand

adhesion performance. Inspired by these principles, we have generated artificial adhesive surfaces

with actuated topographies that allow switching on and off adhesion properties.

References

1) Insights into the adhesive mechanisms of tree-frogs using artificial mimics. D.-M. Drotlef, L.

Stepien, M. Kappl, W. J. P. Barnes, H.-J. Butt, A. del Campo*, Adv. Funct. Mater. in press, DOI:

10.1002/adfm.201202024

2) Bioinspired Actuated Adhesive Patterns of Liquid Crystalline Elastomers, J. Cui, D. M. Drotlef,

I. Larraza, J. P. Fernández, L. Boesel, C. Ohm, M. Metzger, R. Zentel, A. del Campo*; Adv.

Mater. 2012, 24, 4601–4604

3) Switching adhesion with bioinspired actuated magnetic patterns. D. Drotlef, A. del Campo, in

preparation

ANTIBACTERIAL STRATEGIES FROM THE SEA: POLYMER BOUND CL-

CATECHOLS FOR PREVENTION OF BIOFILM FORMATION

Luis García-Fernández, Jiaxi Cui, Cristina Serrano, Zahid Shafiq, Jagoba Iturri Ramos,

Aránzazu del Campo

Max-Planck-Institut für Polymerforschung, Mainz (Germany)

Ackermannweg 10, 55128 Mainz, Germany

Natural strategies to prevent bacterial colonization offer great promise for the development of

effective, biocompatible and environmentally friendly non-fouling coatings. Inspired by the

aminoacid 2-chloro-4,5-dihydroxyphenylalanine (Cl-DOPA) present in the composition of the

proteinaceous glue of the sandcastle worm Phragmatopoma californica, we present a simple

strategy to confer antifouling properties to polymer surfaces using (but not releasing) a

bioinspired biocide. Taking advantage of the catechol reactivity, Cl-dopamine was easily

incorporated into hydrogels or co-deposited as thin coating. Polymer bound Cl-catechol groups

effectively prevented bacteria attachment while they showed no toxicity on attached cells. The

antifouling performance of Cl-dopamine depended on the flexibility of the polymer chain to

which it was attached (i.e. the accessibility of the Cl-catechol groups to interact with the bacterial

membrane) and it was concentration dependent. The simplicity, low cost and flexibility of this

strategy promises wide application for antibacterial coatings of biomedical devices of almost any

kind.

THE BEETLE IN RUBBER BOOTS: RESILIN GRADIENT IN THE ADHESIVE SETAE

OF COCCINELLA SEPTEMPUNCTATA

Henrik Peisker1, Jan Michels1, Alexander Filippov2 and Stanislav Gorb1

1 Department of Functional Morphology and Biomechanics, Zoological Institute, Christian-

Albrechts-

University of Kiel, Am Botanischen Garten 1-9, D-24098 Kiel, Germany,

[email protected], [email protected]

2 Donetsk Institute for Physics and Engineering, National Academy of Science, Donetsk, Ukraine

In hairy pads of beetles, the contact formation with various substrates requires high flexibility of

their adhesive setae. However, too strong flexibility of setae may result in a decrease of their

mechanical stability and therewith in the condensation of setae and in the reduction of the

adhesion efficiency. Here, by using methods of atomic force microscopy (AFM) and confocal

laser-scanning microscopy (CLSM), we show an evidence for a pronounced longitudinal gradient

in the material composition and properties of adhesive setae of the ladybird beetle (Coccinella

septempunctata). The Young’s modulus ranges from approximately 1 MPa at the setal tip, where

we found the incorporation of high proportions of the elastic protein resilin, to about 7 GPa at the

setal base.

Our results and numerical model let us assume that this gradient likely represents an evolutionary

optimisation increasing performance of the adhesive system by efficiently adapting to uneven

substrates while simultaneously preventing lateral collapse of the setae. In this context, our

finding reveals an important aspect of material composition of biological attachment devices.

Implementation of the described structural principle into artificial dry adhesives may lead to new

biologically-inspired systems with an enhanced performance.

THE ADHESIVE SYSTEM OF THE FLATWORM MACROSTOMUM LIGNANO: A

MORPHOLOGICAL AND MOLECULAR BIOLOGY ANALYSIS

Birgit Lengerer1, Robert Pjeta1, Julia Wunderer1, Marcelo Gomez Rodrigues1, Willi

Salvenmoser1, Roberto Arbore2, Eugene Berezikov3, Lukas Schärer2, Peter Ladurner1

1University of Innsbruck, Center of Molecular Bioscience Innsbruck,

Institute of Zoology, Technikerstr. 25, 6020 Innsbruck, Austria 2Schärer Group Evolutionary, Institute of Zoology, University of

Basel, Vesalgasse 1, CH-4051 Basel Switzerland 3European Research Institute for the Biology and Ageing, and University Medical Center

Groningen, University of Groningen, 9713-AV Groningen, The Netherlands and Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center

Utrecht, Uppsalalaan 8, 3584CT Utrecht, The Netherlands Free-living flatworms are able to adhere and release from the substrate using a duo-gland adhesive organs. The adhesive organs consist of three cell types, an adhesive gland, a releasing gland, and a modified epidermal cell called anchor cell. Our model organism - the free-living flatworm Macrostomum lignano possesses about 120 adhesive organs, which enable the worm to adhere to and release rapidly from the substrate. Firstly, we analysed the morphology of the adhesive organs using light- and electron microscopy. The adhesive organs are organized in a horse-shoe shaped pattern at the tip of the tail plate. About 22-24 specialized microvilli of the anchor cells surround the necks of the adhesive and releasing gland cell. The cell bodies of the adhesive and releasing gland cells are located deeper in the tail plate. The adhesive gland cell is characterized by large vesicles that presumably contain the adhesive molecules. The releasing gland cells possess small vesicles that contain the releasing factors. Secondly, in a whole mount in situ hybridization screen we identified a gene encoding for an intermediate filament protein which was found to be essential for adhesion. We refer to this gene as macIF1 (Macrostomum intermediate filament). Using messenger RNA knock-down by RNA interference we analysed the biological function of this gene. The RNAi treated animals exhibited a non-adhesion phenotype. We unravelled that this failing in attachment was due to altered anchor cell morphology of RNAi treated animals that yield to the lack of intermediate filaments in the anchor cell cytoplasm. Our experiments corroborate that a molecular biology approach allows the identification of adhesion related proteins and can contribute to understand the underlying adhesive mechanism. Supported by FWF grant P25404-B25

SCREENING FOR ADHESION RELATED GENES IN THE FLATWORM

MACROSTOMUM LIGNANO

Robert Pjeta1, Julia Wunderer1, Birgit Lengerer1, Marcelo Rodrigues1, Willi Salvenmoser1,

Roberto Arbore2, Eugene Berezikov3, Lukas Schärer2 and Peter Ladurner1

1Center of Molecular Bioscience Innsbruck, Institute of Zoology, University of Innsbruck,

Technikerstrasse 25, 6020-Innsbruck, Austria 2Schärer Group, Institute of Zoology, University of Basel, Vesalgasse 1, 4051-Basel, Switzerland

3European Research Institute for the Biology and Ageing, and University Medical Center

Groningen, University of Groningen, 9713-AV Groningen, The Netherlands and Hubrecht

Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center

Utrecht, Uppsalalaan 8, 3584CT Utrecht, The Netherlands

The Flatworm Macrostomum lignano is an emerging model organism for developmental-, stem

cell- and evolutionary studies. The main advantage of this flatworm is the possibility of keeping

permanent laboratory cultures, its small size, its high regeneration capacity and the suitability for

applying of diverse molecular biology tools. Their astonishing ability to repeatedly adhere and

release within a short time render this animal suitable for bioadhesion research. M. lignano

possesses about 120 adhesive organs on the posterior end of its tail-plate. Each adhesive organ

consists of three different cell types: one adhesive gland, one releasing gland and one modified

epithelial cell called anchor cell. Our current studies are focused to locate candidate genes and

decipher their involvement in the adhesion process. In this regard, we have bioinformatically

screened the transcriptome of this species. We have identified about 400 genes which are

considered as tail specific. We are now perform a whole mount in situ hybridization screen of a

selected subset of these tail-specific genes. In situ hybridization results showed that we were

successfully identifying adhesion related genes. However the majority of the tail specific genes

belonged to the reproductive system. They were expressed in the worms’ prostate and around the

female opening - the antrum. Currently, we are performing knock-downs of selected candidate

genes using RNA interference to study the function of the respective genes to search for non-

adhesive or non-release phenotypes. It is our goal to identify the full complement of adhesion

related genes using the in situ hybridization screen combined with subsequent functional analysis

by RNAi.

Supported by FWF grant P25404-B25

A MOLECULAR BIOLOGY APPROACH IN BIOADHESION RESEARCH

Marcelo Rodrigues1, Robert Pjeta1, Julia Wunderer1, Birgit Lengerer1, Peter Ladurner1

1Center of Molecular Bioscience Innsbruck, Institute of Zoology, University of Innsbruck,

Innsbruck, Austria. [email protected]

Although conventional morphological tools are making inroads into bioadhesion research, the

current approaches face serious challenges. Molecular tools and the use of multidisciplinary

approaches that take full advantage of all the disciplines should be applied in the field of

bioadhesion. Nevertheless, the use of molecular biology tools in the field of bioadhesion is still in

its infancy. If new research groups consider starting a molecular approach, the following

techniques are essential to unraveling the sequence of a gene, its expression and its biological

function. The most successful approach up to date is the well-established whole mount in-situ

hybridization protocol, with a subsequent phenotypic engineering approach by RNA interference

gene knock-down to manipulate specific genes. This protocol comprises several steps, and is so

far producing reliable results: first, transcriptome assembling and screening provides the full

complement of genes expressed in a certain organism tissue; second, in-situ hybriditazion

provides the temporal and spatial expression of target genes; third, RNAi allows elucidates the

function of a gene. Current studies by the suitability of these methods for adhesion research have

been shown in our model organism, the flatworm Macrostomum lignano and could be

successfully applied to other bioadhesion models.

This research is supported by Austrian Science Foundation

ADHESIVE PROPERTIES OF ASPERGILLUS FUMIGATUS BIOFILMS PROBED BY ATOMIC FORCE MICROSCOPY AND EFFECTS OF ALGINATE LYASE ENZYME

A. Maiorana1, M. Papi1, F. Bugli2, R. Torelli2, B. Posteraro2, V. Palmieri1, G. Ciasca1, M.

Chiarpotto1, G. Maulucci1, M. De Spirito1, M. Sanguinetti2

1 Istituto di Fisica, Università Cattolica del S. Cuore, L.go F. Vito 1, 00168 Roma, Italy

2Istituto di Istituto di Microbiologia, Università Cattolica del S. Cuore, L. go F. Vito 1, 00168 Roma, Italy

E-mail: [email protected]

Aspergillus fumigatus (A. fumigatus) has become a leading cause of fungal morbidity and mortality, especially in immunocompromised patients [1]. This fungus is able to grow as a multicellular community and produce a hydrophobic extracellular matrix (ECM), mainly composed of galactomannan and α1,3 glucans, to protect itself from host defenses and antimicrobial drugs [2]. This matrix envelops the fungus hyphae, binding them into a contiguous sheath on the colony surface, forming the biofilm and increasing the fungal resistance to adverse environmental factors [3]. Adhere to host cells and resist physical removal play a key role in fungal colonization and invasion of the host and in a wide range of infections. In cases of pharmacological investigations, the efficiency of an antifungal agent can only be assessed by clinical symptoms since repeated biopsy and fungal cultures hinder continuous observation of treatment response [4].

Combining high resolution atomic force microscopy (AFM) and adhesion force spectroscopy we were able to detect simultaneously the pathophysiological conditions of ECM, hyphae and spores. We show that, by using AFM, is possible to exploit the peculiar hydrophobicity of the biofilm components (i.e. cell walls, ECM) to detect the biofilms spread, its growth and lysis on rough surfaces.

We tested our approach by means of several pharmacological strategies commonly used in clinic-treatment, moreover we tested a new approach based on Alginate Lyase (AlgL), an enzyme known to reduce negatively charged alginate levels in microbial biofilms [5]. We also mixed these with amphotericin B (AMB) deoxycholate and its lipid formulations (e.g., liposomal AMB [LAMB]). AFM analysis showed that when A. fumigatus biofilms were treated with AlgL or polyene alone, as well as with their combination, both a reduction of hyphal thicknesses and an increase of adhesive forces were observed compared to the findings for untreated controls, probably owing to the different action by the enzyme or the antifungal compounds. Our results suggest that a combination of AlgL and a polyene antifungal may prove to be a new therapeutic strategy for invasive aspergillosis, while reinforcing the EPS as a valuable antibiofilm drug target. Finally, an important fall out of our results is that AFM and adhesion force spectroscopy, it’s possible to develop an effective diagnostic tool able to detect the pharmacological effects on biofilms fungus and thus to transfer advanced microscopy techniques to a clinical purpose.

Bibliography 1. G. R. Thompson and T. F. Patterson, Semin. Respir. Crit. Care Med. 29, 103 (2008). 2. C. Loussert, C. Schmitt, M. C. Prevost, V. Balloy, E. Fadel, B. Philippe, C. Kauffmann-Lacroix, J. P. Latgé and A. Beauvais, Cellular Microbiol. 12, 405 (2010). 3. E. Mowat, J. Butcher, S. Lang, C. Williams and G. Ramage, J. Med. Microbiol. 56, 1205 (2007). 4. J. Weber and E. Balish. Mycopathologia 90, 47 (1985).

5. M. A. Alkawash, J. S. Soothill and N. L. Schiller, APMIS 114, 131 (2006).

Figure 1. Atomic force micrographs of mature A. Fumigatus biofilms imaged before treatment (A) and after treatment with AlgL (B), AlgL-AMB (C), or AlgL-LAMB (D). Topographic images (top) show hyphae from each experimental condition, as indicated, after they were grown as sessile cells for 24 h at 37°C in static and aerial environments. Deflection images (middle) reveal more details in hyphal cell texture, whereas three-dimensional (3-D) topographic images (bottom) depict clear differences in hyphal thickness between treated (B to D) and untreated control (A) samples.

THE ADHERING ABILITIES OF TREE FROGS ON ROUGH SURFACES

Niall Crawford

Centre for Cell Engineering, University of Glasgow

Tree frogs possess highly adapted toe pads which secrete a mucus that allows them to adhere

through a combination of capillary and viscous forces. This, combined with a specialised cell

morphology, culminates in the toe pads producing impressive adhesive and frictional forces.

However, most experiments thus far have been conducted on smooth surfaces; although these

highlight the animal’s capabilities, tree frogs are more likely to encounter rough surfaces in nature,

such as a branch or a leaf. Here, the abilities of the toe pads of White's Tree Frogs

(Litoria caerulea) are tested on rough surfaces for the first time. Adhesive and friction forces

were recorded from individual toe pads using a 3-D force transducer, with a motorised stage

mimicking steps taken by the pad. Multiple force plates were created from embedding resin, with

surfaces of varying roughness (smooth, 30, 6, 2 and 0.5 µm rough surfaces). The performance of

the frogs' toe pads varied for each surface, with adhesion being reduced by the larger scale

roughness, and friction forces increasing on all rough surfaces. Performance on smaller scale

roughness doesn't vary from that on a smooth surface. These results indicate that there is a

roughness scale where tree frog adhesion performs least effectively, while smaller levels of

roughness do not detrimentally affect their pads.

POSTERS Wednesday 10th April

STRUCTURE AND RHEOLOGICAL PROPERTIES OF CHITOSAN/POLY(VINYL

ALCOHOL) MIXTURES AS MATERIALS DESIGNED FOR BIOMEDICAL

APPLICATIONS

Katarzyna Lewandowska, Alina Sionkowska

Nicolaus Copernicus University, Faculty of Chemistry, 7 Gagarin Street, 87-100 Toruń

The physico –chemical properties of polymer mixtures are important from both scientific and

practical point of view. The mixtures composed of chitosan with poly(vinyl alcohol) (PVA) at

various component ratio have been prepared as material designed for biomedical applications.

The structure and properties of blends of chitosan acetate with PVA depends mainly on the

molecular weight, the degree of hydrolysis of PVA and the blend composition.

The purpose of this study was to evaluate the physico –chemical properties of chitosan with

poly(vinyl alcohol). The properties of chitosan (Ch), poly(vinyl alcohol) (PVA) and their

mixtures have been investigated by the tapping-mode atomic force microscopy (AFM) and

rheological measurements of relatively concentrated solutions. Chitosan and PVA were

solubilized separately, in 0.1M aqueous acetic acid and then blended at different weight ratios.

These solutions were cast to prepare the blend films for AFM studies.

The flow measurements were carried out under the change of sample properties such as degree of

hydrolysis PVA, molecular weight, and under variable experimental conditions such as

temperature, shear rate, and blend composition.

The changes of topography images were considered by determining the root mean square (RMS)

deviation in the image data. The study of mixtures by AFM showed a completely different

morphology when compared with pure components. This may indicates a strong interaction

between the polymeric components.

INFLUENCE OF THE ROOT CANAL FILLING MATERIAL ON THE RETENTIVE

STRENGTH OF SELF ADHESIVE RESIN CEMENTS – AN IN VITRO STUDY

Bogdan Baldea1, Gabriel Furtos2, Luminita Nica3

1Department of Prosthodontics, Faculty of Dental Medicine, Victor Babes University of Medicine and Pharmacy, Timisoara, Romania.

2Department of Dental Materials, “Raluca Ripan” Institute of Research in Chemistry, Cluj-Napoca, Romania.

3Department of Endodontics, Faculty of Dental Medicine, Victor Babes University of Medicine and Pharmacy, Timisoara, Romania.

Introduction. Glass fiber posts adhesively cemented into the root canal are widely accepted by practitioners in the restoration of endodontically treated teeth. The aim of the present study was to evaluate the influence of two types of root canal filling materials on the push-out bond strength of a new self-adhesive resin cement (RelyX U200, 3M ESPE, Seefeld, Germany) used for luting glass fiber posts into root canals. Materials and Methods. Thirty recently extracted human maxillary and mandibular premolars were used in this study. The root canal preparation was completed with a size 40 master apical file, 10% taper, using rotary GT instruments (Dentsply Tulsa Dental, OK, US). Teeth were randomly divided into three groups (n=10), according to the root canal filling material: Group I-Epiphany SE + Resilon; Group II-AH Plus+ Gutta-percha; Group III - no root canal filling (control group). RelyX Fiber posts no. 3 were cemented with RelyX U200 (RXU2) (3M ESPE, Seefeld, Germany) in each root canal. Six sections of 1-mm height were cut from each specimen and tested for push-out. A constant load (0.5 mm/min until failure) was then applied only onto the post surface, until a bond failure occurred. The retentive strength (S) (MPa) was calculated by dividing the load at failure (F) (N) to the interfacial area (A) of the post segment (mm2). Failure modes were classified as: A: adhesive failures between the dentine and the luting agent; B: adhesive failures between the post and the cement; C: cohesive failures within the post or dentine; M: mixed failures (between the dentine - luting agent and between the post - cement). Ten randomly selected specimens from each group were prepared for SEM observation. The data were statistically analyzed by one-way analysis of variance (ANOVA) and Tukey’s post-hoc analysis. Results. The mean push out values were statistically significant different (p>0.05) between Group I (10.9±3.08 MPa) and Group II (7.0±2.74 MPa). No differences with Group III (8.9±3.5 MPa) were recorded (p<0.05). Significant differences were observed between the apical and the middle regions in Groups I and II (p<0.05). The predominant failure mode for Group I (90.82%) and Group II (71.43%) was a mixed one. For Group III a higher percentage of adhesive failures (84.96%) between dentine and cement was observed. SEM evaluation revealed numerous resin tags formed by Epiphany SE sealer with the intratubular dentine of the root canal. Conclusions. The type of the root canal filling material influences the strength bond to the root canal dentine of RXU2 cement. The mean push-out bond strength of teeth samples in Group I was significantly higher than that observed in Group II. The absence of the root canal filing material in Group III (control group) did not significantly influence the mean push-out bond strength. The study showed a good bonding capability between RXU2 and Epiphany SE.

FROM LIGNIN TO NEW BIO-BASED POLYMERS

Klaus Rischka1, Anju Brooker2

1Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM), Wiener

Straße 12, 28359 Bremen, Germany 2Procter & Gamble, Newcastle Innovation Centre, Whitley Road, Newcastle upon Tyne NE12

9TS, United Kingdom

Within the FP7 PEOPLE project (Blue4Glue), Fraunhofer Institute (IFAM) and Procter and

Gamble discovered a (PPO based) enzymatic process used by marine-organisms, which produce

polymers in a much simpler way (less process steps) than industry does in classical chemistry.

BIO-MIMETIC aims to transfer this new scientific knowledge into a blueprint for a novel (pre-)

industrial enzymatic-based bio-polymerization process. It involves research partners (IFAM and

UNITOV) with experience in enzymatic transformation and bio-based synthetic polymers, as well

as expert SMEs such as Dyadic (enzymes), CIMV (biomass transformation into bio-chemistry)

and CULGI (computational modelling of bio-chemical processes) to develop the process that

firstly transforms biomass (lignin) into new bio-based polymers (pseudo peptides). These will

used to create respectively:

1) Bio-conjugated copolymers, that will be tested in detergents (by P&G)

2) Bio-cross-linked adhesive gels, to be experimented in anti-ageing cosmetics and in bio-textiles

preparation (by an SME cosmetic producer MAVI).

Potential environmental benefits are over 124 kton/yr less toxic solvents to produce chemicals,

over 1 Billion kWh of energy savings (room temperature process) and a drastically reduced CO2

footprint i.e. replace 8000 Mtons of petrochemical based deposition aides and in the future

substitute a large amount of phenol and phenolic derivatives, which are used to produce chemical

intermediates for a myriad of applications. BIO-MIMETIC will carry out LCA and LCC (cost)

assessments over the value chain as input to business plan and will use a new SME LCA tool

(cCALC) to develop an LCA showcase, which will come available for SMEs. The cCALC tool

and showcase will be freely downloadable as part of the exploitation plan targeted at the market

uptake of project results in the emerging European market of bio-based products, projected to

grow towards 250 billion Euro by 2020.

INTERACTION OF LIPIDS WITH LECTINS

Roxana-Diana Pasca,a,b and Daniel Frankela

aChemical Engineering and Advanced Materials, NewcastleUniversity, Newcastle Upon Tyne, E-

mail: [email protected]. bChemical Engineering Department, Babes-Bolyai University of Cluj-Napoca, Romania.

The interaction of proteins with lipids is fundamental in understanding the processes that

take place in vivo. For this propose, atomic force microscopy (AFM) was used to investigate the

interaction between lectins and supported lipid bilayers.

Supported lipid bilayers containing DOPC and DPPC in a 3:1 molar ratio were prepared

using the method described by Nordin et al. Lectin from triticum vulgaris was adsorbed on pure

mica surface and on supported lipid bilayers.

The AFM images and force curves for pure DOPC, pure DPPC, DOPC: DPPC (3:1)

mixture, pure lectin and lectin on supported lipid bilayers were obtained. The results show

specific interactions between those lipids and lectin from triticum vulgaris.

Acknowledgement

One of us (Roxana-Diana Pasca) received financial support from Sectorial Operational Programme for Human Resources Development 2007-2013, co-financed by the European Social Fund for financial support (project number POSDRU/107/1.5/S/76841).

Bibliography:

Nordin D.,Yarkoni O., Savinykh N.,Donlon L., Frankel D., “Revealing the selective interactions

of fibronectin with lipid bilayers”, Soft Matter, 7 (22), 10666-10675, 2011.

THE CROSS-LINKING INFLUENCE ON THE MECHANICAL PROPERTIES

AND SWELLING BEHAVIOUR OF ALGINATE/K-CARRAGEENAN HYDROGEL

FILMS

1Violeta Pascalău, 1Violeta Popescu, 1George Liviu Popescu, 1Mircea Cristian Dudescu,

2Gheorghe Borodi, 3Adrian Dinescu

1Technical University of Cluj-Napoca, 103-105, Muncii Avenue, Cluj-Napoca, Romania

2National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath Street, Cluj-Napoca, Romania

3National Institute for Research and Development in Microtechnologies, 126 A Erou Iancu Nicolae Street, Bucharest, Romania

[email protected] (Violeta Pascalău) The aim of paper is the study of the mechanical and swelling behaviour of the alginate/k-

carrageenan hydrogel films obtained through three different cross-linking ways. There have been

prepared alginate/k-carrageenan hydrogel films with different alginate:k-carrageenan ratio,

ionically with Ca2+, coordinatively with Zn2+ and covalently with adipic dihydrazide cross-linked.

There were prepared samples of five formulations of alginate/k-carrageenan hydrogels

films with different ratio of alginate:k-carrageenan, (1:1), (1:2), (2:1), (1:3) and (3:1) respectively,

by each cross-linking way.

We have mneasured the mechanical properties, Young’s modulus (E), tensile strength

(σu) and elongation at tensile strength (εu) for all the studied samples.

The swelling behaviour of the hydrogels samples was studied using two reported methods

[1,2]

Our study is focus on the evaluation of the cross-linking influence on the mechanical

properties and the swelling behaviour of the alginate/k-carrageenan hydrogel films samples.

References:

[1] J.B. Xu, J.P. Bartley, R.A. Johnson, Preparation and characterization of alginate-carrageenan

hydrogel films crosslinked using a water soluble carbodiimide (WSC),J. Membr. Sci. 218 (2003)

131–146.

[2] A. Pourjavadi, G. R. Mahdavinia, Superabsorbency, pH-Sensitivity and Swelling Kinetics of

Partially Hydrolyzed Chitosan-g-poly(Acrylamide) Hydrogel, Turk J. Chem. 30 (2006) 595 – 608.

EVALUATION OF ADHESION FOR TWO EXPERIMENTAL ENDODONTIC

SEALERS BY PUSH-OUT TEST

Doina Prodan1, Cristina Prejmerean1, Gabriel Furtos1, Ovidiu Pastrav2, Stanca Boboia1, Laura

Silaghi-Dumitrescu1, Violeta Popescu3, Marioara Moldovan1, Radu Silaghi-Dumitrescu4, Monica

Saplontai3

1”Babes Bolyai” University – “Raluca Ripan” Chemistry Research Institute, Cluj-Napoca,

ROMANIA; 2“Iuliu Hatieganu”University of Medicine and Pharmacy, Faculty of Dentistry,

3Technical University of Cluj-Napoca 4Babes-Bolyai University, Faculty of Chemistry and Chemical Engineering, Arany Janos Street,

no. 11, 400028 Cluj-Napoca, Romania

The bonding adhesion to the dentin walls should eliminate any space that could allow leaching fluids between the filling material and the root canal wall. The quality adherence to the root canal may be influenced by the proteins soluble in water, enzymes and the salts from blood serum. The push-out test provides a better assessment of the adherence than conventional shear tests because the fracture occurs parallel to the dentin-cement interface. This test is intended to assess the extent to which the sealer and core material are bonded into a solid mass as well as the strength of the bond to the canal wall. The aim of this study was to evaluate in vitro the sealing abilities of two experimental endodontic sealing materials E1 and E2. The experimental endodontic sealing materials (E1, E2) were prepared as a paste by dispersing in the organic phase of the bioactive inorganic fillers with different initiation systems (self curing and dual-cured). The teeth were obturated with the experimental endodontic sealing materials with / without gutta-percha cones in the dental office by warm vertical condensation. Samples were immersed in 2.5 ml of cow blood and hemoglobin derivatized for 42 days at 40C in a refrigerator without changing immersion solution. After removing the teeth from the dipping solutions, they were washed with distilled water and were embedded in resin. For obtaining tooth slice have used a cutting device of saw microtome (IsoMet 1000, Buehler Ltd., Lake Bluff, IL, USA). The strength and the interfacial strength, the dislocation between the filling material and the root canal walls was evaluated using thin slices of 1 mm thickness of teeth obturated with and without the gutta-percha cones. Push-out test was conducted on a universal mechanical testing machine LOYD. The average value obtained for shear strength ranged from 22.17 ± 1.5 to 15.36 ± 1.8 MPa for all samples investigated. These results can be explained by lower volume occupied endodontic material in the dentinal tubules.

Acknowledgments: This work was funded by: the Romanian Ministry of Eductaion and Research, National project PNII no: 165/2012, is gratefully acknowledged; the Doctoral School of the Faculty of Materials and Environment Engineering, Technical University of Cluj-Napoca.

THE STRUCTURAL INVESTIGATION OF 4 EXPERIMENTAL BIOCOMPOSITES

Stanca Boboia1,2, Marioara Moldovan1, Codruta Sarosi1, Cristina Prejmerean1, Doina Prodan1,

Laura Silaghi Dumitrescu1, Saplontai Viorica2, Ioan Ardelean2

1„Babes Bolyai“ University, “Raluca Ripan“ Chemistry Research Institute, Cluj-Napoca,

ROMANIA 2 Tehnical University, Cluj-Napoca, ROMANIA


Development of new generation of bone-like composite materials with improved of

mechanical properties and biocompatibility, requires a synthetic biomimetics approach using natural bone as a guide. Natural bone is itself a nanocomposite composed principally of HA nanocrystallites in organic matrix of collagen.

The purpose of this study is to investigate the structure of composite materials for their application as biomimetic biomaterials for implementation of absorbable implants used in arthroscopy.

Biocomposites materials were made as a polymerizable paste, based on the prepared organic liquid component and the two synthesized inorganic fillers. Were developed composite biomaterials based on L-polylactic acid/hydroxyapatite (PLLA / HA), L-polylactic acid/hydroxyapatite/chitosan (PLLA / HA / CHT) and polycaprolactone / hydroxylapatite / tricalcium phosphate (PLC / HA / TCP). The polymerized materials, with a dual initiation system, are presented as a homogeneous solid with smooth and glossy surface consists of a single phase, in which, the inorganic filler is in the proportion of 40 - 55% and the polymeric matrix at a rate of 65 - 60%.

Investigation of composite biomaterials by electron microscopy revealed hydroxyapatite structure and the role of polylactic acid in the link of hydroxylapatite in composite system.

To determine the structure of the experimental biocomposites we used a FTIR spectroscope Spectrum BX2, where we can see bands specific for groups which exist in the structure. Determination of the structure of materials in which exists polylactic acid was performed by atomic force microscopy-AFM, where we can observe the differences topography of the two composite analyzed with different composition.

Based on the experimental results of macro-and microscopic analysis of bioactive assemblies, we will determine how is produce the physical and/or chemical interaction between nano-and micro-structured matrixes with the bone tissue.

Acnknowledgments: Funding from the Romanian Ministry of Education and Research, National project PNII no: 165/2012, is gratefully acknowledged.

EFFECT ON ADHESION TO TOOTH STRUCTURE OF NEW EXPERIMENTAL

ADHESIVE SYSTEMS BASED ON MODIFIED POLYALCHENOIC ACIDS

Cristina Prejmerean1, Tinca Buruiana2, Moldovan Moldovan1, Gabriel Furtos1, Stanca Boboia1,

Doina Prodan1, Laura Silaghi-Dumitrescu1, Stanca Boboia1, Ioana Hodisan3, Loredana Colceriu3

1”Babes-Bolyai” University, “Raluca Ripan” Chemistry Research Institute, Cluj-Napoca, RO

2“Petru Poni”, Institute of Macromolecular Chemistry, Iasi, RO 3“Iuliu Hatieganu”University of Medicine and Pharmacy, Faculty of Dentistry, Cluj-Napoca, RO

OBJECTIVE. The aim of the present study is to elaborate novel adhesive systems with reduced

polymerization shrinkage, and high adhesion to tooth structure.

MATERIALS AND METHODS.

Obtaining of specimens. 20 human premolar teeth in which two class V cavities (3 mm x 4 mm x

1.5 mm) were prepared on facial and oral surfaces with a cervical margin in cementum (dentin). A

new experimental composite material based on an aromatic urethane dimethacrylate Bis-GMA

analogue and Beautifil II giomer respectively, and their proper experimental adhesives were

applied to the cavities. The adhesive systems were prepared for each material as three steps adhesive

(etchant, primer and bonding). The primers contained polyalchenoic acids modified with

polymerizable groups as base components. The teeth were sectioned on an Isomet Low Speed Saw-

Buechler LTD machine.

SEM analisis. SEM photomicrographs of the interfacial region between tooth and restaurations

were performed.

DISCUSSION AND CONCLUSIONS. Using of adhesive systems in which the primers contain

polyalkenoic acids modified with polymerizable groups improve adhesion of resin-based dental

materials to tooth structure. The mechanism of adhesion implies micromechanical interlocking

and chemical interaction, respectively. Both in the case of resin composite and in the case of

giomer, the adhesive layer follows the shape of the dentin surface having approximately the same

width. Signs of strong interactions between the adhesive and dentin can be observed.

ACKNOWLEDGMENTS. This work was supported by Romanian National Project PNII no.

189/2012 (GIODENT), Parteneriate Program

ANALYSIS OF THE DEGRADATION BY SEM AND FTIR OF EXPERIMENTAL COMPOSITES

Laura Silaghi Dumitrescu1, Doina Prodan1, Violeta Popescu2

,, Cristina Prejmerean1, Gabriel

Furtos 1, Stanca Boboia1, Sarosi Codruta1, Marioara Moldovan1

1Babes Bolyai University - Raluca Ripan Chemistry Research Institute, Cluj-Napoca, RO

2Technic University of Cluj-Napoca,RO

Introduction. Composition and structure of the surface composite filling is extremely important, both in terms of strength and durability particle and its influence on interactions with the resin. In order to reduce the corrosion rate, have tried the application of various coatings on composite materials from the mouth. It is very important and beneficial if biocompatibility and durability of composites could be improved by surface treatments, prolonging its life more than 10 years. Due to these phenomena of corrosion, it was concluded that the surface of a biomaterial play a crucial role in biological interactions. The purpose of this study is to investigate degradation in time,of samples in saliva and water by FTIR and SEM of experimental composites. Experimental composite C18 contains as organic matrix (Bis-GMA), (TEGDMA) and (UDMA) and as inorganic fillers Sr and Zr glass, quartz, hydroxyapatite with Zn. Methods and Materials. To investigate samples were made in a teflon mold with dimensions 15 mm diameter and 1mm thick. Each specimen was irradiated on portions by visible light, making sure that each piece of tested specimen is exposed for 20 sec. These specimens were immersed in water and artificial saliva were analyzed at 18 and 33 days of immersion against a control samples. FTIR spectra were recorded on a spectrophotometer JASCO - 610, in the 400 to 4000 cm-1, and the investigation a sample surfaces was conducted with Electronically microscope Quanta 133 of the FEI company. Results and discussion. IR spectra recorded , revealed characteristic peaks for monomers and peaks characteristic for inorganic phase. For samples immersed in water or artificial saliva was observed reduction the intensity of characteristic peaks Si-O-Si bond. Images SEM recorded show that most fracture on surface of composites were observed in samples immersed in distilled water. Tendency to introduce as much filler in composite, from desire to increase young modulus, wear resistance, compression resistance and reduce thermal expansion, water absorption and polymerization shrinkage of the composite, may present a danger. It may be noted that the filler- organic matrix bond is the most important for a composite and water can cause a break at interface silane-resin and appearance powder at the surface of composite, due destruction filler- organic matrix bond. Acknowledgments: Funding from the Romanian Ministry of Eductaion and Research, National project PNII no: 165/2012, is gratefully acknowledged.

EVALUATION OF MICROLEAKAGE OF DENTAL HARD TISSUES/GIOMER

INTERFACE

Ioana Hodisan1, Gabriel Furtos2, Tinca Buruiana3, Cristina Prejmerean2

Loredana Colceriu1, Maria Tomoaia-Cotisel4

1“Iuliu Hatieganu”University of Medicine and Pharmacy, Faculty of Dentistry, Cluj-Napoca, RO 2”Babes-Bolyai” University, “Raluca Ripan” Chemistry Research Institute, Cluj-Napoca, RO

3“Petru Poni”, Institute of Macromolecular Chemistry, Iasi, RO 4”Babes-Bolyai” University, Faculty of Chemistry and Chemical Engineering, Cluj-Napoca, RO

The aim of this study was to analyze the marginal integrity in cavities restored with classic giomer in combination with two different adhesive systems. Material and methods. The experimental series included 9 teeth, extracted from orthodontic and periodontal reasons. Eighteen box-type Class V standardized cavities were prepared on the facial and oral surfaces of each tooth, with coronal margins in enamel and apical margins in cementum (dentin). The preparations were divided randomly into two equal groups and restored with giomer Beautiful (Shofu), in combination with three different adhesive systems: group 1 FL BeautiBond (Shofu) and group 2,3 – 2new experimental adhesive systems for which the primer contained polyalchenoic acids modified with polymerizable groups as base components. The teeth were thermocycled and immersed in 2% methyl blue solution for 12 hours. The specimens were sectioned buccolingually into 3 slices and the resulted sections were examined using a stereomicroscope under 20x magnification. The extent of dye penetration was scored using the Iso microleakage scoring system (ISo/TS 11405:2003). These percentage values were submitted to variance analyses (ANOVA) and t test at a p<0.05 level of significance. Results. The dye penetration score for groups 1(FL bond) and 2 (experimental) for the occlusal wall (enamel) were similar and better than for the group 3 (experimental). The dye penetration score for group 1 for the gingival wall (dentin) showed significant differences compared to group 2 and 3: group 1 performed better than group 2 and 3. The groups 2 and 3 performed similar compared to each other. There was a significant difference recorded between the bonding effectiveness to enamel and dentin in the control groups that needs further investigations. Conclusion. Further research should provide enlightening data on the in vitro performance of the giomer resin-based material when used in combination with experimental total etch adhesive systems. ACKNOWLEDGMENTS This work was supported by Romanian National Project PNII no. 189/2012 (GIODENT), Parteneriate Program

Obtaining Allium cepa extracts for medical use

Aniela Saplonţai-Pop1, Augustin Moţ3, Radu Silaghi Dumitrescu1, Corina Ionescu1, Marioara Moldovan2

1 „Iuliu Hatieganu” University of Medicine and Pharmacy, Cluj-Napoca, ROMANIA 2„Babes Bolyai“ University, “Raluca Ripan“ Chemistry Research Institute, Cluj-Napoca ,

ROMANIA 3„Babes Bolyai“ University, Cluj-Napoca, ROMANIA


Several studies of literature reveals the complex composition of Allium cepa, including flavonoids (quercetin, kaempferol, myricetin), antocianic pigments, saponins, organosulfur compounds (S-alk(en)yl-L-cysteine sulfoxide) and their degradation compounds: thiosulfinates and polysulphide. The last are known for their antiplatelet effect, inhibiting platelet aggregation.1

While crushing the Allium cepa bulbs, S-alk(en)yl-L-cysteine sulfoxides are metabolized, by aliinases, generating thiosulfinates compounds. 2-3 The extract reduces the TxA2 formation and the lipooxigenase pathway products formation from exogenous arachidonic acid, acting a step after its release. The results show that the inhibition of platelet aggregation in the presence of Allium cepa extract is mediated by its effects on production of TxA2.

3

We have tried to standardize the process for obtaining the Allium cepa extract, which could be used in primary prevention, in cardio-vascular pathology. We used seven varieties of onions of different regions, grown on different soils, approximately in the same period of the year. The extract was obtained by crushing and squeezing the dried substance using an electric juicer; then left at room temperature for 30 minutes, the time for the reaction between S-alk(en)yl-L-cysteine and aliinase to take place, with the formation of thiosulfinates compounds; these are the compounds that give the antiplatelet effect. It is also necessary to pass some time between extraction and testing the antiplatelet effect, time for the molecules of ADP and ATP, released from broken mitochondria, to enter in chemical reactions, in order to avoid their proaggregant effect. The extract, obtained like this, was subjected to centrifugation process 10 minutes, at 13000 rpm, for removing debris of cell wall. The supernatant recovered after centrifugation is filtered with a filter G3, from the vacuum pump. To identify the compounds, the extracts thus obtained were analysed by UV-VIS. 1. Singh Bora K, Sharmab A. Phytoconstituents and Therapeutic Potential of Allium cepa Linn.– A Review. Phcog Rev. 2009;3(5):170-80. 2. Osmont K, Arnt K, Goldman I. Temporal aspects of onion-induced antiplatelet activity. Plant Foods for Human Nutrition 2003;58:27–40. 3. Srivastava KC. Onion exerts antiaggregatory effects by altering arachidonic acid metabolism in platelets. Prostaglandins Leukot Med. Sep 1986;24(1):43-50.

EVALUATION OF COLOUR CHANGES IN COMPOSITE MATERIALS AFTER APPLICATION OF BLEACHING AGENTS

Ovidiu Pastrav1, Laura Silaghi Dumitrescu2, Stanca Boboia2, Doina Prodan2, Aniela Pop1,

Mihaela Pastrav1, Marioara Moldovan2

1 „Iuliu Hatieganu” University of Medicine and Pharmacy, Cluj-Napoca, ROMANIA 2„Babes Bolyai“ University, “Raluca Ripan“ Chemistry Research Institute, Cluj-Napoca ,

ROMANIA E-mail:[email protected]

Several recent studies combated the theory regarding the need to replace esthetic restorations after a dental whitening treatment in order to relate to the new situation obtained after bleaching.1,2. Studies demonstrate that composite materials suffer a process of bleaching during the application of bleaching agents on their surface. Our study follows the changes of color that occur on the surface of specimens (30X2mm) made of composite materials, which after coloring with various colorants were subjected for bleaching using two experimental gels with 15% (GA) hydrogen peroxide and 15% peroxidase (GAP). We used for our investigation two commercial light-cured composites: RestacrilRO (ICCRR) and Premise (Kerr). Those were immersed for 3 weeks in coffee and commercial non-carbonated juice (Giusto with cherry). After immersion, the samples were removed from the solution, cleaned with water and dried, and then subjected to the bleaching process for 8 hours, some with GA gel and some with GAP gel. After the bleaching period, the samples were kept in distilled water. To determine the change of color, we used the CIELAB system (L *, a *, b *), using a lighting type C with geometry sphere of 8°, calculating the color difference ΔE* by the formula: ΔE* = (�L*2+�a*2+�b*2)1/2. Measurements were made with a UV-VIS spectrophotometer (UNICAM). To observe the structure of composites before and after the bleaching process we used SEM microscopy (FEI Quanta). Color coordinate values ΔE* after bleaching process compared to initial values of all samples are smaller after the whitening process. The best results for ΔE* were obtained for GA whitening gel USED ON PREMISE. The images presented by SEM point out the gentle effect of the bleaching agents on the composite surface. Acknowledgments: Funding from the Romanian Ministry of Eductaion and Research, National project PNII no: 165/2012, is gratefully acknowledged.

References:

1.M.Bizhang, Y.H.Chun,K.Damerau, P.Singh, W.H.Raab, S.Zimmer,Oper.dent.2009,34, 635; 2.B.A.Matis, M.A.Cochan, G.Eckert. Oper Dent 2009, 34, 230. 3.M. Moldovan, L. Silaghi-Dumitrescu, C. Prejmerean, D. Dudea, V. Popescu, S. Boboia, D. Prodan, I. Cojocaru, Plastics Materials,Vol.47, No.4, 2010

STUDY OF MECHANICAL PROPERTIES OF FORSTERITE CERAMICS USING

NANOINDENTATION METHOD

Marieta-Adriana NAGHIU1, Maria GOREA1, Maria TOMOAIA-COTISEL1, Daniel

FRANKEL2

1Babes-Bolyai University of Cluj-Napoca, Faculty of Chemistry and Chemical Engineering, 11

Arany J. Str., 400028 Cluj-Napoca, Romania 2Newcastle University, School of Chemical Engineering and Advanced Materials, Newcastle

upon Tyne, NE1 7RU, United Kingdom

Forsterite (Mg2SiO4) ceramics were obtaining from forsterite powders, which were synthesized

by two different methods. Powders by sol-gel approach [from magnesium nitrate (Mg(NO3)2.

6H2O) and tetraethoxysilane (TEOS)] calcined at 900 0C and by solid state reaction [from

magnesium carbonate (MgCO3) and talc (Mg3Si4O10(OH)2)] calcined at 1100 0C were used.

Forsterite pellets were compacted by pressing the powder at 500 kgf/cm2. Then, the pellets were

sintered with heating rate 4 0C/ min till 1400 0C and 2 hours at highest temperature. Compactness

characteristics were determined for all samples. The apparent porosity for sample obtained from

sol-gel method sintered at 1400 0C is about 26% and for the solid state powders is about 17%.

Hardness and elastic modulus of these materials were measured by nanoindentation using a

nanoindenter type Hysitron TI 900 Triboindenter coupled with atomic force microscope (AFM).

The size of the residual impression (nanoindentation impression) was imaged using AFM. Elastic

modulus for ceramics obtained from sol-gel powders is between 20-40 GPa and the hardness

about 2 GPa. For ceramics obtained from solid state reaction powders these characteristics are

between 80-100 GPa and respectively 8 GPa. It can be noticed that specific mechanical properties

were enhanced about 4 times for sintered samples obtained from solid state reaction powders in

comparison with sintered samples prepared from sol-gel method powders.

Acknowledgment. This work was possible with the financial support from POSDRU/107/1.5/S/76841 for “Modern Doctoral Studies: Internationalization and Interdisciplinarity”.

BIOMATERIALS MADE OF HYDROXYAPATITE AND COLLAGEN TYPE 1 WITH

POTENTIAL APLLICATIONS IN MEDICINE

Ancuţa Dăniştean1, Ana Madalina Budaca1, Alexandra Ioana Gog1, Aurora Mocanu1,

Gheorghe Tomoaia2, Liviu Dorel Bobos1 and Maria Tomoaia-Cotisel1

1Babes-Bolyai University of Cluj-Napoca, Research Centre of Excellency in Physical Chemistry,

Arany Janos Str., No. 11, 400028 Cluj-Napoca, Romania; 2Iuliu Hatieganu University of Medicine and Pharmacy, Orthopedic Department, Mosoiu Street,


A systematic study on nano-structuring processes within interfacial materials,

of nano hydroxyapatite (nanoHAP) and collagen type 1 (COL) was carried out with the aim of

assessing the effects of COL self assembled layers on nanoHAP. Structures of these materials

were investigated by FTIR, RAMAN, X-ray diffraction, AFM, TEM and SEM. The surface

nanostructure and mechanical properties of obtained interfacial materials were notably different

than for films cast from collagen solutions due to the COL interaction with nanoparticles of

hydroxyapatite. The obtained multifunctional biomaterials based on nanoHAP and COL layers

mimic to some extend the bone structural organization, particularly because bone is a nano

composite consisting of COL matrix with nanoHAP crystals embedded in it. The obtained

materials have high stability and might have medical applications, particularly for the treatment

of osteoporosis with antifracture efficacy.

MODIFIED NANOSTRUCTURED HYDROXYAPATITE WITH MEDICAL

APPLICATIONS

Valer Almasana, Mihaela D. Lazara, Gheorghe Tomoaiab, Aurora Mocanuc, Corina Garboc,

Laura Ciupeiuc, Camelia Ciobotariuc, Adriana Andoniec, Cristina Spelmezanc, Liviu Dorel

Bobosc and Maria Tomoaia-Cotiselc

a National Institute for Research and Development for Isotopic and Molecular Technologies –

INCDTIM, Donath Street, no. 65-103, 400293 Cluj-Napoca, Romania bIuliu Hatieganu University of Medicine and Pharmacy, Orthophaedics and Traumatology

Department, Traian Mosoiu Street, no. 47, 400132 Cluj-Napoca, Romania cBabes-Bolyai University, Faculty of Chemistry and Chemical Engineering, Arany Janos Street,


The majority of grafting materials for bone grafts are autografts and alografts. However, porous ceramic materials such as calcium phosphates, in particular hydroxyapatite (HAP: Ca10(PO4)6(OH)2) are considered an important class of future biomaterials for bone reconstruction. Current research in this field strives to exploit their osteoconductive, osteoinductive and osteogenic properties, but their low mechanical properties and their unpredictable osteointegration are disadvantageous. The main goal of our work is to obtain and characterize new modified nanostructured hydroxyapatite (HAP) compatible with bone tissue. Ten nanomaterial samples were prepared by wet chemical methods. The additive materials for the hydroxyapatite based samples were: Si, Ag, aluminosilicate (AS), and collagen. The structural and compositional influence of additive materials upon the specific surface area, pore volumes and pore size distribution of modified HAP, also the crystal composition and internal structure of modified HAP samples were studied using BET and Dollimore-Heal methods, XRD and FTIR spectroscopy, respectively. The thermal treatment of samples strongly influences the texture of modified HAP.

The aim of our group is to develop hydroxyapatite based materials with enhanced mechanical properties, as well as design of rods/ceramic blocks with a suitable porous structure for osteoblastic cell adhesion. Modifications of HAP were achieved by addition of Si (under different concentrations), Ag, aluminosilicates, or collagen in the presence of glutaraldehide as reticulation agent, in both acidic and basic mediums. These were characterised by determination of porosity, pore size distribution, specific surface area (BET method), determination of crystallite dimensions and crystallinity (XRD), and by structural determination (FTIR). Addition of aluminosilicates to hydroxyapatite reduces the crystallinity of materials at low temperature treatment. Addition of aluminosilicates to hydroxyapatite modifies the number of OH groups, and the quality of the nanoHAP surface. By adding Ag, a well structured HAP based material can be obtained. In the case of collagen addition, the crystallinity and crystallite dimensions are greater if the preparation medium is basic. Moreover, the collagen molecules are well bonded to the hydroxyapatite matrix. In the case of the two rod samples the crystallite structure is little influenced by the thermal treatment.

THE EFFECT OF HYDROXYAPATITE NANOPARTICLES

ON COLLAGEN MINERALIZATION

Gheorghe Tomoaia1, Alexandra-Gertrud Hosu-Prack2, Ioan Petean2,

Aurora Mocanu2 and Maria Tomoaia-Cotisel2

1 Iuliu Hatieganu University of Medicine and Pharmacy, Orthophaedics and Traumatology Department, 47 Traian Mosoiu Str., 400132 Cluj-Napoca, Romania

2Babes-Bolyai University of Cluj-Napoca, Faculty of Chemistry and Chemical Engineering, Physical Chemistry Department, 11 Arany J. Str., 400028 Cluj-Napoca, Romania

In the present work, we describe the effect of nanoparticles of hydroxyapatite (HAP) or modified HAP with Si, Mg, and Zn (HAP-Si-Mg-Zn), on the mineralization process of collagen type I (COL). We examine the size and shape of inorganic particles by AFM and SEM imaging and their crystalline structure by XRD. Also, the surface morphology of collagen self-assemblies has been investigated by AFM imaging and AFM force spectroscopy and the structure and mechanical properties of collagen fibrils in the absence and the presence of inorganic phase are explored. The AFM observations indicate that the image resolution is high for these composite biomaterials, which are stabilized through interactions between collagen molecules and inorganic phase particularly in the presence of increased Si content. The AFM images are in substantial agreement with SEM and TEM observations. The dominant feature on AFM images is the presence of collagen fibrils with their characteristics. Pure collagen assemblies imaged with AFM exhibited a transverse banding pattern with a period of about 67 ± 5 nm in substantial agreement with theoretical modeling. The nodule structure of collagen fiber shows the different mass density across the fibrils of collagen, both in the absence and in the presence of inorganic phase, where the transverse banding pattern has almost a similar aspect, with a slightly enlarged value (approximate 70 ± 6 nm) in the case of biomaterials with nanoHAP size under 20 nm, and are hardly observed for bigger particles of about 100 nm in diameter. AFM images taken from different samples show that the surface features of collagen fibers are quite different depending on the granulation of used inorganic powder. The collagen fibrils are extended for several μm reaching occasionally over 20 μm. The collagen fibers appear to show a strong structural relationship to chemical composition of inorganic powders, made of various calcium phosphates, powder nanoparticles as well as of the presence of various mineralizing agents, like serine content. The structural features are further related with mechanical properties of these materials determined by AFM force spectroscopy, in terms of force versus distance curves.

INCLUSION MECHANISM OF LIPOIC ACID INTO CYCLODEXTRIN

Szabolcs Santa, Csaba-Pal Racz and Maria Tomoaia-Cotisel

Babes-Bolyai University of Cluj-Napoca, Research Centre of Excellency in Physical Chemistry,

Arany Janos Str., No. 11, 400028 Cluj-Napoca, Romania

The inclusion mechanism of α-lipoic acid (LA) into β-cyclodextrin (β -CD) is investigated due to

the high importance of increased aqueous solubility and enhanced photostability of LA requested

for its large applications as anti-oxidant in medicinal use through oral administration. Different

preparation methods were employed to obtain an α-lipoic acid- β -cyclodextrin (LA: β-CD)

inclusion complex and to determine the physical– chemical characteristics and the interactions

present in this inclusion compound. The formation of the solid inclusion compound was

confirmed by X-ray powder diffraction, differential scanning calorimetry (DSC) and infrared

spectroscopy (FTIR). FTIR and DSC data confirm the new obtained compound. The crystalline

structure of this compound belongs to the monoclinic system with four molecules in the unit cell. 1H NMR spectroscopic method was employed to study the inclusion process in aqueous solution.

Job plots derived from the 1H NMR spectral data demonstrated an 1:1 stoichiometry of the

inclusion complex in liquid state. 2D NMR data suggest the orientation of LA with the carboxylv

group near to narrower rim of the β -CD. The crystal structure of the inclusion complex of β -

cyclodextrin with lipoic acid was determined from laboratory powder diffraction data.

Thermogravimetric data was used to estimate the number of water molecules in the crystal

structure. Lipoic acid is included in β -cyclodextrin through its primary face with the five-

membered ring reaching the center plane of the cyclodextrin cavity and its fatty acid chain

adopting a bent conformation. lipoic acid and β-cyclodextrin form a channel-like packing which

is stabilized by guest–host hydrogen bonding and close contacts, host–host intermolecular

interactions and hydrogen bonding involving water molecules.

About Cluj Napoca Settled along the Someş river, Cluj-Napoca (Kolozsvár, Klausenburg) city is one of the most important academic, cultural and industrial centers in Romania. Considered to be the historic capital of Transylvania, the city is located in northwestern part of Romania and it is one of the most visited cities in the country. The city spreads circle-wise from St. Michael's Church – built in 14th century – named after Michael the Archangel, the patron saint of Cluj-Napoca.

Many hotels and restaurants as well as museums, historical or archaeological monuments, galleries, botanical garden, shopping centers, banks or exchange offices are within walking distances from the conference site.

The climate in Cluj-Napoca is relaxing and refreshing due to a relatively constant temperature (winter average -1.9 oC, summer average: 18.7 oC). During June, the weather is pleasant with the ambient temperature varying normally between 15-25°C.

More information about Cluj-Napoca and a digital map of the city can be found here: www.cluj4all.com/navigator/ http://www.romaniatourism.com/cluj.html About Babes-Bolyai University The Babes-Bolyai University (UBB—Universitatea Babes-Bolyai) in Cluj-Napoca is the largest university in Romania. With almost 50,000 students, the university offers 105 specialisations, of which there are 98 in Romanian, 52 in Hungarian, 13 in German, and 4 in English. The university was named after two prominent Transylvanian scientists, the Romanian scientist Victor Babes and the Hungarian mathematician János Bolyai. Etnography Museum of Transylvania The Ethnographical Museum of Transylvania is the first ethnographical museum in Romania that unfolded its activity continuously since it was founded. This institution gathered with patience and scientific competence, in the 8th decades of its activity, tens of thousands of proofs of the traditional civilization in the Romanian space.

We invite you to visit the 5th permament exhibition of our museum named: Folk Culture in Transylvania - 18th - 20th centuries. The exhibition is open between 9 a.m. and 5 p.m., from Tuesday to Sunday.

Museums • University Museum • Museum of Mineralogy • Botanical Museum • Paleontology-Stratigraphy Museum • Vivarium • Zoological Museum

PRACTICAL INFORMATION University Guest House of Babes Bolyai University, Str. Pandurilor nr. 7 Cluj Napoca 400376 Romania

Some of the taxi companies in Cluj-Napoca: Nova Taxi - (0264) 949, +40-745 151000 Diesel Rapid - (0264) 946 Taxi Pritax - 0264/942 Money in Romania The currency in Romania is the New Lei (RON), Foreign currencies can be exchanged at banks and in many exchange offices located in different places of the town. Many cash dispensers are found, accepting any type of international credit cards. Banking hours are from 9:00 – 17:00. Saturdays and Sundays banks are closed. Turist Info Cluj Tourist Information Centre (Centrul de Informare Turistica) Address: Blvd. Eroilor 6-8, Telephone: (264) 452.244 or 452.249 Email: [email protected] The Tourist Information Centre provides maps, brochures and information on accommodations, restaurants and transportation. Telephoning Cluj Napoca from Abroad International Access Code + 40 (country code) + 264 or 364 (area code) + telephone number (six digit number) Pharmacies & Hospitals There are several pharmacies (farmacie) open 24 hours a day in the city. Emergency Clinic Hospital (Spitalul Clinic Judetean de Urgenta Cluj). Address: Str. Clinicilor 3-5, Tel: (264) 592.771 Cluj-Napoca - Useful Telephone Numbers Cluj-Napoca Area Code (Prefix Cluj-Napoca) 264 or 364 Ambulance (Ambulanta) 961 Police (Politia) 955 Fire Department (Pompierii) 981 Local & County Archives (Arhivele locale) (264) 598.979City Hall (Primaria) (264) 196.030 Better Business Bureau (264) 431.368 International calls (Convorbiri internationale) 971 SHOPPING There are two of the biggest malls: Iulius Mall and Polus Center. You can also visit Sora Shopping Center, Central Shopping Center.

Map of the city

UBB-Hotel DOWNTOWN

Documents

COST Action TD0906 · 2014-10-30 · P6. Doina Prodan, Cristina Prejmerean Gabriel Furtos, Ovidiu Pastrav, Stanca Boboia, Laura Silaghi-Dumitrescu, Violeta Popescu, Marioara Moldovan,