TY - JOUR A1 - Symietz, Christian A1 - Lehmann, Erhard A1 - Gildenhaar, Renate A1 - Krüger, Jörg A1 - Berger, Georg T1 - Femtosecond laser induced fixation of calcium alkali phosphate ceramics on titanium alloy bone implant material N2 - Femtosecond lasers provide a novel method of attaching bioceramic material to a titanium alloy, thereby improving the quality of bone implants. The ultrashort 30 fs laser pulses (790 nm wavelength) penetrate a thin dip-coated layer of fine ceramic powder, while simultaneously melting a surface layer of the underlying metal. The specific adjustment of the laser parameters (pulse energy and number of pulses per spot) avoids unnecessary melting of the bioactive calcium phosphate, and permits a defined thin surface melting of the metal, which in turn is not heated throughout, and therefore maintains its mechanical stability. It is essential to choose laser energy densities that correspond to the interval between the ablation fluences of both materials involved: about 0.1-0.4 J cm-2. In this work, we present the first results of this unusual technique, including laser ablation studies, scanning electron microscopy and optical microscope images, combined with EDX data. KW - Bone implant KW - Bioceramic coating KW - Titanium KW - Calcium phosphate KW - Femtosecond laser PY - 2010 DO - https://doi.org/10.1016/j.actbio.2010.02.016 SN - 1742-7061 VL - 6 IS - 8 SP - 3318 EP - 3324 PB - Elsevier CY - Amsterdam AN - OPUS4-21446 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Winkler, T. A1 - Hoenig, E. A1 - Huber, G. A1 - Janssen, R. A1 - Fritsch, D. A1 - Gildenhaar, Renate A1 - Berger, Georg A1 - Morlock, M.M. A1 - Schilling, A.F. T1 - Osteoclastic bioresorption of biomaterials: Two- and three-dimensional imaging and quantification N2 - Purpose: Bioresorbable materials have been developed in the hope that the body will replace them with newly formed tissue. The first step of this remodeling process in bone is the bioresorption of the material by osteoclasts. The aim of this study was to analyze osteoclastic resorption of biomaterials in vitro using the commonly used two-dimensional methods of light-microscopy (LM) and scanning electron microscopy (SEM) in comparison with infinite focus microscopy (IFM), a recently developed imaging method allowing for three-dimensional surface analysis. Methods: Human hematopoietic stem cells were cultivated in the presence of the cytokines M-CSF and RANK-L for 4 weeks directly on dentin and a calcium phosphate cement. Osteoclast development was surveyed with standard techniques. After removal of the cells, resorption was characterized and quantified by LM, SEM and IFM. Results: Osteoclast cultures on the biomaterials presented the typical osteoclast-specific markers. On dentin samples LM, SEM as well as IFM allowed for discrimination of resorption. Quantification of the resorbed area showed a linear correlation between the results (LM vs. SEM: r=0.996, p=0.004; SEM vs. IFM: r=0.989, p=0.011; IFM vs. LM: r=0.995). It was not possible to demarcate resorption pits on GB14 using LM or SEM. With IFM, resorption on GB14 could be visualized and quantified two- and three-dimensionally. KW - Biomaterial KW - Three-dimensional KW - IFM KW - Osteoclast KW - Dentin KW - Calcium phosphate PY - 2010 SN - 0391-3988 VL - 33 IS - 4 SP - 198 EP - 203 PB - Wichtig Ed. CY - Milano [u.a.] AN - OPUS4-21621 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Symietz, Christian A1 - Lehmann, Erhard A1 - Gildenhaar, Renate A1 - Koter, Robert A1 - Berger, Georg A1 - Krüger, Jörg T1 - Fixation of bioactive calcium alkali phosphate on Ti6Al4V implant material with femtosecond laser pulses N2 - Bone implants made of metal, often titanium or the titanium alloy Ti6Al4V, need to be surface treated to become bioactive. This enables the formation of a firm and durable connection of the prosthesis with the living bone. We present a new method to uniformly cover Ti6Al4V with a thin layer of ceramics that imitates bone material. These calcium alkali phosphates, called GB14 and Ca10, are applied to the metal by dip coating of metal plates into an aqueous slurry containing the fine ceramic powder. The dried samples are illuminated with the 790 nm radiation of a pulsed femtosecond laser. If the laser fluence is set to a value just below the ablation threshold of the ceramic (ca. 0.4 J/cm²) the 30 fs laser pulses penetrate the partly transparent ceramic layer of 20–40 µm thickness. The remaining laser fluence at the ceramic–metal interface is still high enough to generate a thin metal melt layer leading to the ceramic fixation on the metal. The laser processing step is only possible because Ti6Al4V has a lower ablation threshold (between 0.1 and 0.15 J/cm²) than the ceramic material. After laser treatment in a fluence range between 0.1 and 0.4 J/cm², only the particles in contact with the metal withstand a post-laser treatment (ultrasonic cleaning). The non-irradiated rest of the layer is washed off. In this work, we present results of a successful ceramic fixation extending over larger areas. This is fundamental for future applications of arbitrarily shaped implants. KW - Bone implant KW - Bioceramic coating KW - Titanium KW - Calcium phosphate KW - Femtosecond laser PY - 2011 DO - https://doi.org/10.1016/j.apsusc.2010.10.046 SN - 0169-4332 SN - 1873-5584 VL - 257 IS - 12 SP - 5208 EP - 5212 PB - North-Holland CY - Amsterdam AN - OPUS4-23310 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -