Browsing by Author "Starikov, V. V."

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    The application of niobium and tantalum oxides for implant surface passivation.
    (Jointly by, Collegium Basilea (Institute of Advanced Study) and Association of Modern Scientific Investigation., 2007) Starikov, V. V.; Starikova, S. L.; Mamalis, A. G.; Lavrynenko, S. N.; Ramsden, Jeremy J.
    Despite the advantages of ceramics, with their high corrosion stability in vivo, most medical implant constructions are still made from metals [1]. To increase the corrosion stability of metals, different coatings are applied to the implant surfaces, typically such coatings are the oxides of the metals in the implants [2]. For an oxide film to have protective properties it must satisfy the following requirements: • to be unbroken and pore-free; • to have good adhesion with the metal; • to have a thermal expansion constant near to the value for the metal; • to be chemically inert in different environments; • to be hard and have minimal wear under load. The oxides of metals such as Al, Ti, Zr, Nb and Ta satisfy all these properties to some degree [3–5]. Indeed, some of these metal oxides are used in medicine independently without a metal substrate, such as implant constructions from sapphire (a single-crystal modification of Al2O3) [6, 7]. Titanium is the most widely used material for medical implant manufacture [8]. Its chemical passivity is provided by the oxide film (TiO2), covering the entire free surface; a result of titanium contact with air. But titanium is unable to satisfy all the requirements necessary for an implant material because of its insufficient corrosion stability [9–11]. The application of combined implants consisting of a metal base and a ceramic coating also does not give a complete solution to the problem, because of the low adhesion strength and fragility of ceramic coatings [12, 13].
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    Chitosan–hydroxyapatite composite biomaterials made by a one step co-precipitation method: preparation, characterization and in vivo tests
    (Collegium Basilea & AMSI, 2009-09) Danilchenko, S. N.; Kalinkevich, O. V.; Pogorelov, M. V.; Kalinkevich, A. N.; Sklyar, A. M.; Kalinichenko, T. G.; Ilyashenko, V. Y.; Starikov, V. V.; Bumeyster, V. I.; Sikora, V. Z.; Sukhodub, L. F.; Mamalis, A. G.; Lavrynenko, S. N.; Ramsden, Jeremy J.
    A series of biocompatible chitosan/hydroxyapatite composites has been synthesized in an aqueous medium from chitosan solution and soluble precursor salts by a one-step coprecipitation method. The composite materials were produced in dense and porous variants. XRD and IR studies have shown that the apatite crystals in the composites have structural characteristics similar to those of crystals in biogenic apatite. A study of in vivo behaviour of the materials was carried out. Cylindrical rods made of the chitosan/ hydroxyapatite composite material were implanted into the tibial bones of rats. After 5, 10, 15 and 24 days of implantation, histological and histo-morphometric analyses of decalcified specimens were undertaken to evaluate their biocompatibility and the possibility to apply them in bone tissue engineering. The calcified specimens were examined by scanning electron microscopy combined with X-ray microanalysis to compare the elemental composition and morphological characteristics of the implant and the bone during integration. Porous specimens were osteoconducting and were replaced in vivo by newly formed bone tissue.
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    Influence of implant surface modification on integration with bone tissue
    (Jointly by, Collegium Basilea (Institute of Advanced Study) and Association of Modern Scientific Investigation., 2008) Kutsevlyak, V. I.; Starikova, S. L.; Starikov, V. V.; Mamalis, A. G.; Lavrynenko, S. N.; Ramsden, Jeremy J.
    Problems connected with the improvement of medical implant fixation in bone tissue are addressed by the formation of a highly developed surface and by the activation of the implant surface with an electret coating. The realization of such surface modifications is expedient for implants manufactured from tantalum or niobium or finished by coatings made from these metals, as they are chemically more inert than titanium. The techniques have been tested on animals followed by histological and mechanical analysis.