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European Coatings Conference
Extra
Pre-Conference Tutorial
09 April 2008
Berlin, Germany
Main conference
"Medical Coatings and Adhesives"
10/11 April 2008
Berlin, Germany
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 Welcome
At a Glance
Tutorial
Abstracts
Delegates Section
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| Events > European Coatings Conferences > Medical Coatings and Adhesives > Abstracts |
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MAIN CONFERENCE: Abstracts
| THURSDAY, 10 April 2008 |
Focus paper: Testing methods |
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In vitro and in vivo evaluation of antimicrobial surfaces for infection control
Prof. Henk J. Busscher, University Medical Center Groningen, The Netherlands
Biofilm formation on biomaterials implant surfaces and subsequent infectious complications are a frequent reason for failure of biomedical devices. Microbial adhesion is influenced by the physico-chemical properties of the biomaterial surface, and proper antimicrobial coatings should be non-adhesive and bactericidal. In vitro evaluation of new biomaterials coatings, as mostly done, unfortunately does not include any host response to the foreign body. However, In-vivo imaging systems (IVIS), however, allow to monitor the viability of bioluminescent bacteria on implant surfaces in live animals. Here, a validation of an IVIS based evaluation method for soft tissue implants is presented for S. aureus Xen29.
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| SESSION I: Polymeric Surface Design |
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Chemically designed nanostructured functional surfaces
Prof. Sanjay Mathur, Institute of New Materials, Germany
Thin film deposition by CVD techniques plays a dominant role in the development of both protective and functional coatings, important for their technological implications. Commonly, multi-component materials are prepared from a mixture of precursors; however the efficiency of such processes is hampered by the mis-match of chemical reactivity such as thermal stability, vapour pressure etc. among the precursor species. As a consequence, phase separation and elemental segregation is commonly observed in CVD deposited materials. Transformation of precursor compounds possessing bonding features inherent to the solid-state lowers the need of diffusion and counterbalances the thermodynamic impediments. Recently, we have designed several new metal-organic systems and demonstrated their suitability in thermal and plasma-enhanced CVD techniques to deposit coatings for corrosion-resistance, bio-compatiblity and sensing applications on metallic and non-metallic substrates.
Nanoscopic metal oxide and carbonitride surfaces are finding extensive applications as biocompatible coatings due to their chemical inertness and tuneable topography. We have deposited thin, nanocrystalline films of TiO2, ZrO2 and ZrCN which show chemical, physical and morphological properties suitable towards the acceptor tissues with regard to clinically desired interactions and therefore are used in surgical instruments and implants. Biocompatible coatings on implants can prolong the retention time in human bodies in combination with as few as possible side effects. Therefore cell acceptance together with certain mechanical properties is important for functional coatings. Our investigations have shown that process parameters strongly influence the resulting film morphologies and film compositions, which determine the cell behaviour on the fabricated surfaces. We have investigated the biocompatible properties of the CVD films, by cultivating and analyzing three different cell types (Osteoblasts, MC373-E1; Endothelial Cells, GM7373 and Vero fibroblasts, Vero B4). This talk will present the results concerning the role of nanotopography and surface composition on functional behaviour.
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Lubricity: adding comfort to medical devices
Paul Wyman, DSM Medical Coatings, The Netherlands
Many medical devices benefit from reduced friction surfaces. The advantage comes to both patients and practitioners; improved comfort for patients; enhanced control for the practitioner. Basic lubricant coatings (PEGs, silicone oils) are prone to dissolution and wear-off during use. Non-migratory, wear resistant e.g. fluorinated coatings are also to be found especially on metallic devices where performance can be enhanced compared to uncoated devices. However, levels of friction do not compare with the feel of lubricants. This paper will present an overview of the current hydrophilic coating technology available to achieve low coefficients of friction with high wear resistance on a broad range of substrates. This approach combines the best of both worlds for adding comfort to medical devices.
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Application conditions and practical experiences with PVD-coatings for surgical instruments and medical device parts
Stefan M. Musche, Plasmotec Coating GmbH, Germany
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Hydrophilic Coatings for Medical Devices
Dr. Jürgen Köcher, Bayer MaterialScience AG, Germany
Hydrophilic polymers are important coating materials used in many technical applications. Such coatings are of particular importance for medical devices like catheters, guide wires or endoscopes since a hydrophilic coating is needed for appropriate handling. These instruments have to overcome a significant friction while being inserted into the urethral tract, into blood vessels or while being passed through human tissue. These frictional forces can cause micro lesions within the tissue which cause discomfort or even pain for the patient. On highly hydrophilic surfaces water almost perfectly spreads water to form a homogeneous film thus reducing the frictional forces during the handling of these devices.
New water-borne and solvent-borne polyurethane coatings will be presented which generate very hydrophilic surfaces without the need for further surface modifying steps.
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Synthetic bioactive surfaces by controlled radical polymerisation
Dr. Erik Wischerhoff, Fraunhofer-Institute for Applied Polymer Research(IAP), Germany
Polymers synthesised by controlled radical polymerisation have gained considerable attention during the past few years in the field of surface modification with biomedical scope. They possess potential for a variety of applications, including chromatography [1], cell manipulation [2], biosensing [3] and microarray technology [4].
Some of these polymers are responsive to external stimuli, e. g. temperature and / or pH [5], which makes them particularly attractive for some applications [6]. Like the frequently employed poly(N-isopropylacrylamide) (PNIPAM) [7], statistical copolymers of oligo(ethylene glycol) derivatives belong to this class of substances. Recently, it was demonstrated that they offer some specific advantages over PNIPAM [8]. We have immobilised such copolymers at various interfaces, using the grafting from and the grafting onto approach and explored their potentials and advantages for biomedical applications.
[1] Okano et al., Langmuir 23, 9409-9415 (2007)
[2] Collard et al., Advanced Materials 19, 1724-1728 (2007)
[3] Chilkoti et al., Langmuir 22, 3751-3756 (2006)
[4] Klok et al., Biomacromolecules 6 1602-1607 (2005)
[5] Li et al., Macromolecular Rapid Communications 28 828-833 (2007)
[6] Laschewsky et al., Stimuli-Responsive Polymer Coatings, European Coatings Conference "Smart Coatings III", Berlin, Germany June 7-8, 2004
[7] Biesalski et al., Macromolecules 39, 7258-7268 (2006)
[8] Lutz et al., Journal of the American Chemical Society 128, 13046-13047 (2006)
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A review of the benefits of polymers based on 2-acrylamido-2-methylpropane sulphonic acid in medical applications: coatings, electrodes, wound care and dermal delivery systems.
Dr. Geoff Marks, Lubrizol Ltd., Great Britain
The unique nature of 2-acrylamido-2-methylpropane sulphonic acid (see below) lends itself to many applications: textiles, oilfield, water treatment, medical hydrogels, biomedical equipment, personal care and coatings. There are currently over 1000 papers/patents citing the use of polymers based on this molecule. The properties of hydrogels and polymers made from the monomer are utilised in medical applications such as biocompatible electrocardiograph electrodes and surface coatings with high lubricity for medical equipment. A review of these and other potential medical applications such as drug delivery and wound care are discussed.
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Surface-modified microsystems for biomedical applications
Dr. Oswald Prucker, University of Freiburg, Institute of Microsystem Technology (IMTEK), Germany
As medical devices - especially biosensors and microfluidic chips - are getting smaller and smaller, the properties of the surfaces that are in contact with the biological solutions are getting more and more important, if not dominant. Crucial parameters in this regard are the precise control of the interaction of surfaces with proteins and/or cells and techniques for the spatially resolved deposition of biomolecules at the surface, e.g. for sensor applications. In this contribution we will describe strategies to tailor the surface properties of microsystems such as biosensors or microfluidic devices by depositing thin and ultrathin polymeric layers. Applications will be described in which these layers are used to generate protein-repellent surfaces, to direct cell adsorption and proliferation as well as for the lab-on-a-chip applications.
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| FRIDAY, 11 April 2008 |
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| SESSION II: Adhesive innovations |
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Mussel proteins as a basis for the development of novel medical adhesives
Dr. Klaus Rischka, Fraunhofer-Institute for Production Technology and Applied Materials Research (IFAM), Germany
Bonding of living tissue by using biocompatible adhesive systems is a requisite application in medical engineering that has been subject of studies for some time. In bone regeneration applications, adhesives based on epoxides and acrylates are readily used. These systems currently have several drawbacks as they hamper the healing process of the glued tissue due to phlogistic or allergic reactions and also display insufficient hardening in wet conditions. Approaches concerning bonding of soft tissue to implants are unknown so far, although such adhesives based on mussel proteins have an enormous potential e. g. in the case of dental implants. The blue marine mussel Mytilus edulis has the ability to adhere to a wide variety of surfaces in sea water: e.g. glass, plastic, metal, wood, and even PTFE. Therefore the modification of conventional adhesive systems with sequences from the polyphenolic mussel adhesive-protein is a new trendsetting approach for the development of special adhesives for medical application.
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Innovative pressure sensitive adhesives systems for direct skin contact applications
Andreas Dobmann, Collano AG, Switzerland
Pressure sensitive adhesives for direct skin contact are amazingly versatile. Beside the bonding properties they are able to provide additional functionalities, such as antimicrobial properties, moisture control or wound healing process stimulation. Ecologically friendly, solventless pressure sensitive adhesives based on UV curable acrylics or thermoplastic polymers will be presented and silver release rate studies on products with antimicrobial functionality will be discussed. A novel hydrocolloid adhesive concept with moisture control properties will be introduced. Interesting combinations of pressure sensitive adhesive with different backing materials will be shown.
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| SESSION III: Novel materials and methods |
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Surface modification of medical devices by bioactive plant polysaccharides: results from the PectiCoat project.
Dr. Marco Morra, Nobil Bio Ricerche, Italy
A rich and still partially unexplored reservoir of bioactive molecules is provided by several classes of plant polysaccharides. Indeed, a number of complex plant polysaccharides exist, that display, e.g. antiinflammatory activity, exploited since the beginning of the history of mankind in traditional herbs and medicines. Advancements in separation and purification of complex polysaccharides such as pectins are paving the way to a conscious exploitation of some of these properties. A multidisciplinary research project (Pecticoat, Nanobiotechnology for the coating of medical devices) was carried on under the 6th EU Framework Programme, to investigate the use of pectin fractions in the surface modification of medical devices. A number of different pectin fractions were prepared by enzymatic tailoring, showing, e.g., different length of side chains. Surface engineering approaches such as surface functionalisation by deposition from plasma were used to covalently link tailored fractions to materials and medical devices surfaces. In vitro and in vivo evaluations were performed, targeting specific applications such as surface modification of titanium bone contacting devices and testing the role of pectin-modified devices in inflammation. Results clearly demonstrate that coatings of tailored pectins show different biological activities in vitro and affect tissue response in vivo. Pectin coatings are therefore innovative candidates with considerable potential for improving the biocompatibility of medical devices in diverse applications.
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Stimuli-sensitive macro-, micro- and nanogels as sensors and actuators
Prof. Hans-Jürgen P. Adler, Technical University Dresden, Germany
The fascinating feature of stimuli-responsive or "smart" hydrogels is their ability to change their volume reversibly by more than one order of magnitude in response to small changes of environmental parameters, e.g. temperature, pH-value, solvent concentration or ionic strength. The effective utilization of such hydrogels in different systems requires techniques that provide control over the chemical structure as well as the dimensions of the gels. Basically, different hydrogel structures can be prepared as particles, thin layers (films) or bulk material (disks, cylinders). Hydrogel particles can operate as stable colloidal systems (application in catalysis, protein or drug carriers), particle assemblies (application in flow-control devices, chemostats) or particle-based layers (application in sensors; special coatings).
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New concepts of biocompatible and biodegradable photopolymers
Prof. Robert Liska, University of Technology Vienna, Austria
Biocompatible and biodegradable polymers are often based on thermoplastics such as polylactic acid, which can only be processed by a limited number of techniques. For coatings or 3D objects, e.g. scaffolds printed by rapid prototyping, acrylate based monomers like polyethylene glycole diacrylate are often used. In addition to the well known toxicity of acrylate based monomers, degradation products include harmful polyacrylic acid. Therefore, we have recently investigated different vinylester-based monomers that show significantly lower toxicity and good reactivity. Additionally, the degradation products are based on polyvinyl alcohol, which is well known to have good biocompatibility. Further to this, gelatine based photopolymers will be presented. The toxicity of the corresponding monomers and polymers as well as the mechanical properties and degradation behaviour has been investigated.
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Coating of medical implants and devices by inkjet technology
Wilhelm Meyer, microdrop Technologies GmbH, Germany
The ongoing miniaturisation of many products requires a technology capable of dispensing small amounts of liquids. In many applications small volumes down to a few hundred picoliters need to be placed very precisely in volume and location. The materials to be dispensed are very different about formulation and fluidic behaviour which range from low viscous aqueous solutions to viscous materials like adhesives and polymers. One of the most favoured methods meeting the described requirements is the inkjet technology. Beside office printers inkjet technology is already used in several medical applications for coating implants as well as dispensing of small amounts of adhesives. In this talk the basic technology is described, the limitations and advantages are discussed. The presentation of some application examples illustrates the versatility and future potential of this technology.
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