Browsing by Author "Abdulgader, Radwan"

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    Biodegradable ceramics consisting of hydroxyapatite for orthopaedic implants
    (MDPI, 2017) Monsees, Thomas K.; Azem, Funda Ak; Cotrut, Cosmin Mihai; Braic, Mariana; Abdulgader, Radwan; Pana, Iulian; Birlik, Isil; Kiss, Adrian; Booysen, Robin; Vladescu, Alina
    This study aims to analyze hydroxyapatite (HAP) coatings enriched with Mg and Ti prepared by a magnetron sputtering technique on Ti6Al4V substrate. For preparation of the coatings, three magnetron targets (HAP, MgO and TiO2) were simultaneously co-worked. The concentration of Mg added was varied by modifying the power applied to the MgO target. In all coatings, the Ti concentration was maintained constant by keeping the same cathode power fed during the whole deposition. The influence of different Mg dopant contents on the formation of phase, microstructure and morphology of the obtained Ti-doped HAP coatings were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Moreover, the effects of Mg addition upon corrosion, mechanical and biological properties were also investigated. Mg- and Ti-doped HAP coating obtained at low radio-frequency (RF) power fed to the MgO target provided material with high corrosion resistance compared to other coatings and bare alloy. A slight decrease in hardness of the coatings was found after the Mg addition, from 8.8 to 5.7 GPa. Also, the values of elastic modulus were decreased from 87 to 53 GPa, this being an advantage for biomedical applications. The coatings with low Mg concentration proved to have good deformation to yielding and higher plastic properties. Biological test results showed that the novel surfaces exhibited excellent properties for the adhesion and growth of bone cells. Moreover, early adherent vital cell numbers were significantly higher on both coatings compared to Ti6Al4V, suggesting that Mg ions may accelerate initial osteoblast adhesion and proliferation.
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    Sputtered Si and Mg doped hydroxyapatite for biomedical applications
    (IOP Publishing, 2018-01-30) Abdulgader, Radwan; Monsees, Thomas K.
    Hydroxyapatite (HAP) coatings are applied on metallic implant materials to combine mechanical properties of metallic material with bioactivity abilities of HAP ceramic. In this study, HAP coatings with additions of Si and Mg are proposed to be deposited on Ti6Al4V substrates by RF magnetron sputtering. Chemical bonding, morphology, topography and corrosion resistance in simulated body fluids(SBF) of the coatings were investigated. Additionally, mechanical and biological properties of the coatings were evaluated. It was found that the addition of Si and Mg does not influence the formation of a HAP phase. All the coatings exhibited smooth surface and uniform growth, without defects or cracks. Both hardness and elastic modulus of the coated samples decrease with Mg addition in the HAP-Si structure. Both Mg and Si addition into HAP coatings were found to enhance the corrosion resistance of the Ti6Al4V alloy in the SBF solution. Coatings with low Mg content exhibited better corrosion performance. All the coatings investigated were biocompatible, as demonstrated by SaOS-2 bone cell attachment and growth. However, cell proliferation and morphology were inferior on samples with the highest Mg content.