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  • 1
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 39 (1998), S. 524-530 
    ISSN: 0021-9304
    Keywords: magnetron sputtering ; calcium phosphates ; hydroxyapatite ; carbonate apatite ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Radiofrequency magnetron sputter deposition was used to deposit Ca-P sputter coatings on titanium discs, and these coatings were implanted subcutaneously into the backs of rabbits. Half of the as-sputtered coatings were subjected to additional heat treatment for 2 h at 500°C. X-ray diffraction (XRD) demonstrated that annealing at 500°C changed the amorphous sputtered coating into an amorphous-crystalline apatite structure. Scanning electron microscopic (SEM) examination of the sputtered coatings showed excellent coverage of the substrate surface. Annealing of the 4-μm-thick coatings resulted in the appearence of small cracks. SEM demonstrated that until 4 weeks of implantation, all heat-treated coatings were present and all amorphous coatings were completely or mostly dissolved. Fourier transform infrared spectroscopy showed the formation of carbonate apatite (CO3-AP) on these specimens. Furthermore, XRD analysis showed that these CO3-AP precipitated coatings disappeared after 8 weeks of implantation. On the other hand, SEM inspection of these specimens revealed that the 4-μm heat-treated coating was still partially maintained and that small Ca-P crystals were present on the titanium substrate. On the basis of these results, we conclude that apparently 0.1 μm heat-treated Ca-P sputter coating is of sufficient thicknesses to stimulate carbonate apatite deposition under in vivo conditions. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 39, 524-530, 1998.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 40 (1998), S. 464-474 
    ISSN: 0021-9304
    Keywords: calcium phosphate coatings ; magnetron sputtering ; osteoblast ; in vitro ; bone ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: In previous studies we developed a RF magnetron sputter technique for the production of thin Ca-P coatings. With this technique coatings can be produced that vary in Ca/P ratio as well as in structural appearance. The aim of this investigation was to obtain more understanding of the biological behavior of these coatings by way of in vitro experiments. The effect of noncoated titanium (Ti) and three different Ca-P-sputtered surfaces on the proliferation and differentiation (morphology and matrix production) of osteoblast-like cells was studied. Proliferation was determined using counting procedures; morphology was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Fluorescent markers and energy-dispersive X-ray microanalysis (EDX) were used to obtain quantitative and compositional information about the resultant calcified extracellular matrix (ECM). Results demonstrated that proliferation of the osteoblast-like cells was significantly (p 〈 0.05) higher on noncoated than on Ca-P-coated samples. On the other hand, more mineralized ECM was formed on the coated surfaces. In addition, TEM confirmed that the cells on the coated substrates were surrounded by ECM with collagen fibers embedded in crystallized, needle-shaped structures. On the basis of these findings, we concluded that: (1) the investigated Ca-P sputter coatings possess the capacity to activate the differentiation and expression of osteogenic cells, and (2) bone formation proceeds faster on Ca-P surfaces than on Ti substrates. Further, this bone-inductive effect appeared to be dependent on the Ca-P ratio of the deposited coatings. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 40, 464-474, 1998.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 43 (1998), S. 270-276 
    ISSN: 0021-9304
    Keywords: magnetron sputtering ; calcium phosphates ; subperiosteal ; oesteogenesis ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The aim of this study was to obtain more information about the initial biological events around RF magnetron sputtered calcium phosphate (Ca-P) coatings. Therefore, uncoated and coated disks were inserted subperiosteal into the tibia of a goat. The coatings were deposited on commercially pure titanium. The thickness of the coating was 0.1 or 2.0 μm. All the as-sputtered coatings were subjected to an additional heat treatment for 2 h at 500°C. After 1 and 3 weeks of implantation the experimental disks were retrieved and prepared for histological and physicochemical analysis. The histological results demonstrated that the periosteum covered the specimens after both implantation periods. In between the periosteum and implant an acellular layer and a collagen matrix was observed. Energy dispersive spectrometry revealed that the acellular layer consisted of C, Ca, and P ions for the 0.1 μm thick Ca-P coatings. The 2 μm thick Ca-P coatings also showed the presence of sulfate ions in this layer. Only organic material was found on the titanium disks. Further, SEM showed that even after 3-week implantation, a substantial thickness of both coatings was still maintained. Thin film X-ray diffraction demonstrated that after both implantation periods, the CaP-0.1 coating was still present. FTIR of the retrieved specimens demonstrated on the coated disks the formation of additional carbonate apatite (CO3-AP) associated with an organic phase (NH2 groups). On basis of these findings we conclude that our experimental approach is very suitable for the investigation of the healing process around Ca-P coatings. Further, we again demonstrated that the initial interfacial response to Ca-P materials differs from titanium. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 43: 270-276, 1998
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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