The Thematic Days on Interfacial and Surface Engineering (ThGOT) are traditionally not a single event, but rather bundle topics from several specialist areas - this year they took place on June 15 as a duo with the 13th Thuringian Biomaterials Colloquium in Zeulenroda-Triebes in Thuringia.
Both conferences function as a cooperation forum that enables direct contact between scientists and industry representatives and promotes networking. As part of the ThGOT program, one session focused on antibacterial surfaces and a keynote lecture dealt with current trends in the application of physical plasmas for the modification of surfaces in the life science sector.
On the second day of the event, the top-class panels at the 13th Thuringian Biomaterials Colloquium provided current perspectives on the topics of nanomaterials and nanomedicine, biofunctional surfaces and structures for tissue engineering as well as haemocompatible materials and blood-material interactions and discussed the respective topics in detail. The participants were able to bridge the gap between medical research and medical practices.
Antimicrobial effect of a new micro-plasma source
The effect of atmospheric plasmas on biological material has been studied at the Department of Skin Diseases at Jena University Hospital for several years. Sarah Fink was able to present the results of her doctoral thesis on the antimicrobial effect of a new micro-plasma source in a lecture. Specifically, both a very good antimicrobial effect and biocompatibility, which is just as important for dermatological applications, were demonstrated by tests on agar surfaces contaminated with various microorganisms, tests on the chicken egg model and on 3D skin models as well as by means of autofluorescence analysis. Histological confirmation of the results was provided by PAS (periodic acid-Schiff reaction) staining and immunohistology as well as by studies of the expression of pro-inflammatory cytokines and antimicrobial peptides.
Innovative materials in medicine
This topic was the focus of the lecture by Dr. Monika Bach from the Natural and Medical Sciences Institute at the University of Tübingen. Several special fields for tissue engineering - tissue cultivations as replacement material for cartilage, skin and cell transplants - were illustrated with examples. The functionalization of catheter implant surfaces was discussed. Bone replacement materials, especially for jaw regeneration after tooth loss, can be functionalized using liquid collagen foam with embedded encapsulated active ingredients that gel after processing. One project in the field of bioprocessing is electrospinning for a cardiac support system. Non-isocyanate PU (NIPU) is being spun for this purpose. Current development work is also focusing on the challenging provision of suitable "bioinks", i.e. mixtures of 3D-printable biocompatible polymers with cells.
Surface optimization of implants
Dr. Henrike Rebl from Rostock University Medical Centre is researching the surface optimization of implants using plasma nanocoatings using the example of temporary implants in urology. The aim is to prevent incrustations on the catheter surface and to reduce bacterial infections. To this end, incrustation tests were carried out with three selected plastics after antibacterial coating with CuCl2. The coatings were realized with a simultaneous PECVD/PVD hybrid process of DLC layers alternating with plasma Cu sputter layers. The investigations showed that a hydrophilic surface is advantageous for avoiding incrustations. The combination of novel minimally incrusting materials with antimicrobial plasma nanocoatings could offer a new possibility for the design of new ureteral catheter materials.
Investigation of biomaterials with the atomic force microscope
A. Körnig from Bruker Nano GmbH, Berlin, presented the possibilities of investigating the structure, topography and mechanical properties of biomaterials using atomic force microscopy (AFM). These parameters are important because they determine the mobility, behavior and fate of precursor cells. For this reason, it is necessary to investigate processes such as self-organization or adhesion-induced structural changes in more detail. High-speed AFM imaging was used for this purpose. With its help, it is possible to investigate dynamic processes in living cells or the formation of collagen, including the intermediate stages. The viscoelastic properties can also be calculated.
Antibacterial permanent coatings
Antibacterial permanent coatings based on quaternary ammonium compounds was the topic of Dr. Thorsten Laube, Innovent e.V., Jena. He presented two different antibacterial polymer coatings covalently bonded to the surface. Starting from p-vinylbenzyl chloride, two quaternary ammonium salts with different alkyl chain lengths were first produced: Vinylbenzyl-dimethyl-octylammonium chloride (VBCOQ) and Vinylbenzyl-dimethyl-octadecyl-ammonium chloride (VBCODQ), respectively. Atom transfer polymerization (ATRP) and conventional coating (droplet coating) were selected as coating variants. The coatings, which are only a few nanometres thick, were characterized using X-ray photoelectron spectroscopy (XPS) with regard to their layer element composition and layer thickness. Studies of cytocompatibility and antibacterial activity showed similar results for both coating processes in terms of killing bacteria on contact. These antibacterial coatings therefore represent a method of protecting metal objects from bacterial contamination.
