Cardiovascular implants - a market worth billions

The global market for cardiovascular implants is currently estimated to be worth around 15 billion dollars - making it extremely attractive. On top of this, surface coating techniques for catheters and stents are a field of growing importance, as they make novel and personalized therapy and medical treatment possible. "Coatings increase the functionality, lifetime and cost effectiveness, improve the guidance and positioning of the parts, as well as making them easier to handle and reducing the risk of injury to the patient", says Professor Hans-Wilhelm Engels, Head of the Innovation Community Council and Head of Innovation & Specialties at Bayer MaterialScience, where he is responsible for materials for medical devices. The materials that can be used for coatings include hydrophilic and hydrophobic polymers such as polyvinylpyrrolidone (PVP), polyethylene glycol/polyethylene oxide (PEG/PEO), polyvinyl alcohol (PVA) and hyaluronic acid. Since many of these compounds are water soluble they need to be stabilized by cross-linking. Just recently, Bayer presented "Baymedix CD 500", a new coatings platform for tailored drug release. These stable coatings make it possible to release a wide variety of different drugs, ranging from tiny molecules up to protein therapeutics, in a controlled way. The biocompatibility of these systems has been demonstrated both by in vitro as well as in vivo tests. "Over and above this, we are also already working on optimized systems for biodegradable stents", Engels adds.


Surface roughness - 3D measurement on the nanoscale

One of the decisive factors for the quality of implants, apart from selecting the right material, is achieving the ideal surface structure. For instance, the biocompatibility is clearly dependent on the surface roughness. This is especially the case for dental implants, where the roughness on the nanoscale (a billionth of a meter) is decisive for the protein binding capacity and thus for the speed at which they can grow into the jaw bone. In the light of this, Alicona Imaging GmbH (from Grambach near Graz, Austria) has developed an innovative 3D surface measurement technique that is ideally suited to the surface characterization of implants. "In order to perform the measurement cost effectively it is necessary to measure all of the relevant parameters with a single measuring system, and that is precisely what our InfiniteFocus is capable of doing", explains Dr. Stefan Scherer, CEO of Alicona. It combines the possibilities presented by a Roughness Gauge with those of a form measuring instruments, thus offering all of the functions of an optical profilometer as well as a micro coordinate machine. Even for complex forms and different material properties, the user can achieve a resolution of as fine as 10 nanometres, even across large vertical and lateral scanning ranges. For complete measurement of the form it also has an optional rotation unit that can turn the sample through 360°. "We aren't aware of any other optical measuring system like it, which can provide such well-founded information on the roughness, even over large measuring ranges", says Dr. Frank Rupp, Head of the "Interface Analysis of Medical Materials" working group at the polyclinic in Tübingen.

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