Filters

2020 - 20232

More filters

2021 - 20242
Reset filters

Settings

Author: Gebert, Annett × Author: Voss, Andrea × End date: 2023 × Start date: 2020 × DDC: 660 × Has files: Yes ×

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Designing Gallium-Containing Hydroxyapatite Coatings on Low Modulus Beta Ti-45Nb Alloy
    (Basel : MDPI, 2023) Vishnu, Jithin; Voss, Andrea; Hoffmann, Volker; Alberta, Ludovico Andrea; Akman, Adnan; Shankar, Balakrishnan; Gebert, Annett; Calin, Mariana
    Low-modulus β-type Ti-45Nb alloy is a promising implant material due to its good mechanical biocompatibility, non-toxicity, and outstanding corrosion resistance. Its excellent chemical stability brings new challenges to chemical surface modification treatments, which are indispensable for both osteogenesis and antibacterial performance. Coatings containing metal ions as anti-microbial agents can be an effective way to reduce implant-associated infections caused by bacterial biofilm. Gallium ion (Ga3+) has the potential to reduce bacterial viability and biofilm formation on implant surfaces. In this study, a novel two-step process has been proposed for Ga3+ incorporation in hydroxyapatite (HAP) to develop bioactive and antibacterial surfaces on Ti-45Nb alloy. For the generation of bioactive surface states, HAP electrodeposition was conducted, followed by wet chemical immersion treatments in gallium nitrate (1 mM). Different buffers such as phosphate, sodium bicarbonate, ammonium acetate, and citrate were added to the solution to maintain a pH value in the range of 6.5–6.9. Coating morphology and HAP phases were retained after treatment with gallium nitrate, and Ga3+ ion presence on the surface up to 1 wt.% was confirmed. Combining Ga and HAP shows great promise to enable the local delivery of Ga3+ ions and consequent antibacterial protection during bone regeneration, without using growth factors or antibiotics.
  • Thumbnail Image
    Item
    Effect of Selective Laser Melting on Microstructure, Mechanical, and Corrosion Properties of Biodegradable FeMnCS for Implant Applications
    (Weinheim : Wiley-VCH Verl., 2020) Hufenbach, Julia; Sander, Jan; Kochta, Fabian; Pilz, Stefan; Voss, Andrea; Kühn, Uta; Gebert, Annett
    Selective laser melting (SLM) of biodegradable metallic materials offers a great potential for manufacturing customized implants. Herein, SLM processing of a novel Fe–30Mn–1C–0.02S twinning-induced plasticity (TWIP) alloy and the resulting structural, mechanical, and corrosion properties are presented. The occurring rapid solidification results in a fine-grained austenitic microstructure with mainly homogeneous element distribution, which is investigated by scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDX) and electron backscatter diffraction (EBSD) as well as X-ray diffraction (XRD). By processing the alloy via SLM, significantly higher strengths under tensile and compressive load in comparison with those for the as-cast counterpart and a 316L reference steel are achieved. Electrochemical corrosion tests in a simulated body fluid (SBF) indicate a moderate corrosion activity, and a beneficial uniform degradation is shown in immersion tests in SBF. Regarding the envisaged application for vascular implants, SLM-processed stent prototypes out of the novel alloy are presented and a first functionality test is shown. © 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim