TY - JOUR A1 - Kranz, I. A1 - Gonzalez, J.B. A1 - Dörfel, Ilona A1 - Gemeinert, Marion A1 - Griepentrog, Michael A1 - Klaffke, Dieter A1 - Knabe, C. A1 - Österle, Werner A1 - Gross, U. T1 - Biological response to micron- and nanometer-sized particles known as potential wear products from artificial hip joints: Part II: Reaction of murine macrophages to corundum particles of different size distributions KW - Macrophages KW - Cytokines KW - Nanoparticles (NP) KW - Microparticles (MP) KW - Corundum PY - 2009 U6 - https://doi.org/10.1002/jbm.a.32121 SN - 1549-3296 SN - 1552-4965 VL - 89A IS - 2 SP - 390 EP - 401 PB - Wiley CY - Hoboken, NJ AN - OPUS4-19346 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gemeinert, Marion A1 - Dörfel, Ilona A1 - Griepentrog, Michael A1 - Gross, U. A1 - Klaffke, Dieter A1 - Knabe, C. A1 - Kranz, I. A1 - Österle, Werner T1 - Biological response to micron- and nanometer-sized particles known as potential wear products from artificial hip joints: Part I: Selection and characterization of model particles KW - Hip joint endoprostheses KW - Wear products KW - Particle size distribution KW - Model particles KW - Dispersing behavior of particles PY - 2009 U6 - https://doi.org/10.1002/jbm.a.31952 SN - 1549-3296 SN - 1552-4965 VL - 89A IS - 2 SP - 379 EP - 389 PB - Wiley CY - Hoboken, NJ AN - OPUS4-19345 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Österle, Werner A1 - Klaffke, Dieter A1 - Griepentrog, Michael A1 - Gross, U. A1 - Kranz, I. A1 - Knabe, Ch. T1 - Potential of wear resistant coatings on Ti-6Al-4V for artificial hip joint bearing surfaces N2 - Tribological screening tests (simple, reciprocating ball-on-flat tests) were performed with the objective to identify an appropriate coating for the articulating surfaces of artificial hip joints whose acetabular cups and femoral stems are made from Ti–6Al–4V alloy, which is appreciated for its light weight, good biocompatibility and elastic properties similar to those of natural bone. Standard coatings like TiN or CrN performed better than more complicated multi-layer systems, though not as good as different types of amorphous carbon coatings, generally referred to as diamond-like carbon or DLC coatings. Among the latter, hydrogenated amorphous carbon (a-C:H) displayed the best properties, especially if the hydrogen content was increased by reducing the bias voltage during PA-CVD-deposition. The optimised a-C:H coating revealed the most promising wear behaviour under the applied testing conditions, i.e. the increase of linear wear with the number of cycles was close to zero. Regarding the materials examined in this study, correlation of wear with mechanical properties obtained by nano-indentation revealed that high hardness was not an adequate criterion for selecting appropriate coatings. A high ratio of hardness and elastic modulus (H/E) proved to be more important. Microstructural and micro-analytical investigations revealed transformation of TiN and CrN to TiO2 and Cr2O3, respectively, and amorphous carbon was, at least partly, transformed to graphite. Furthermore, incorporation of Al2O3 from the ball was observed at a very fine scale. The wear debris of favourable coatings always formed agglomerates of nano-scale particles. It was shown that commercial nano-particles of Al2O3, Cr2O3 and carbon black are comparable to particles generated by the tribological tests. However, it is uncertain whether they are comparable to those formed during simulator studies or in vivo. Furthermore, the performance of the favourable coating has to be tested in a hip joint simulator before its potential for application in prostheses can be assessed. KW - Coating KW - Implant KW - Titanium alloy KW - DLC KW - Wear debris KW - Nano-particles PY - 2008 U6 - https://doi.org/10.1016/j.wear.2007.04.001 SN - 0043-1648 VL - 264 IS - 7-8 SP - 505 EP - 517 PB - Elsevier CY - Amsterdam AN - OPUS4-16711 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Knabe, C. A1 - Houshmand, A. A1 - Berger, Georg A1 - Ducheyne, P. A1 - Gildenhaar, Renate A1 - Kranz, I. A1 - Stiller, M. T1 - Effect of rapidly resorbable bone substitute materials on the temporal expression of the osteoblastic phenotype in vitro N2 - Ideally, bioactive ceramics for use in alveolar ridge augmentation should possess the ability to activate bone formation and, thus, cause the differentiation of osteoprogenitor cells into osteoblasts at their surfaces. Therefore, in order to evaluate the osteogenic potential of novel bone substitute materials, it is important to examine their effect on osteoblastic differentiation. This study examines the effect of rapidly resorbable calcium-alkali-orthophosphates on osteoblastic phenotype expression and compares this behavior to that of β-tricalcium phosphate (TCP) and bioactive glass 45S5. Test materials were three materials (denominated GB14, GB9, GB9/25) with a crystalline phase Ca2KNa(PO4)2 and with a small amorphous portion containing either magnesium potassium phosphate (GB14) or silica phosphate (GB9 and GB9/25, which also contains Ca2P2O7); and a material with a novel crystalline phase Ca10[K/Na](PO4)7 (material denominated 352i). SaOS-2 human bone cells were grown on the substrata for 3, 7, 14, and 21 days, counted, and probed for an array of osteogenic markers. GB9 had the greatest stimulatory effect on osteoblastic proliferation and differentiation, suggesting that this material possesses the highest potency to enhance osteogenesis. GB14 and 352i supported osteoblast differentiation to the same or a higher degree than TCP, whereas, similar to bioactive glass 45S5, GB9/25 displayed a greater stimulatory effect on osteoblastic phenotype expression, indicating that GB9/25 is also an excellent material for promoting osteogenesis. KW - Bone substitute materials KW - Calcium-alkali-orthophosphate ceramics KW - SaOS-2 cells KW - Osteoblast differentiation KW - Bioactive glass PY - 2008 U6 - https://doi.org/10.1002/jbm.a.31383 SN - 1549-3296 SN - 1552-4965 VL - 84A IS - 4 SP - 856 EP - 868 PB - Wiley CY - Hoboken, NJ AN - OPUS4-16658 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -