Köser, Joachim

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Köser
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Joachim
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Köser, Joachim

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2022 - 20232
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Dateien dazu vorhanden?: Ja × Thema: 600 - Technik, Medizin, angewandte Wissenschaften ×

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  • Vorschaubild
    Publikation
    An origami like 3D patterned cellulose-based scaffold for bioengineering cardiovascular applications
    (Springer, 2023) Rodriguez, Gabriela Melo; Trueb, Donata; Köser, Joachim; Schoelkopf, Joachim; Gullo, Maurizio [in: Cellulose]
    In this work we describe the manufacturing of cellulosic, cell compatible scaffolds with an inherent 3D origami crease pattern for applications in cardiac tissue engineering. Different cellulosic materials were studied, among them cotton linters, fibers obtained from eucalyptus, pine, spruce and lyocell. Formed sheets made of cotton linters were chosen for further study due to the highest biocompatibility and mechanical properties best suited for cardiomyocytes in wet and dry conditions: E - modulus of 0.8 GPa, tensile strength of 4.7 MPa and tensile strength in wet environment of 2.28 MPa. Cell alignment is desired to achieve directional contraction of the cardiac tissue, and several options were investigated to achieve fiber alignment, e.g. a dynamic sheet former and Rapid Köthen sheet former. Although the orientation was minimal, cells cultured on the cellulose fibers grew and aligned along the fibers. Origami inspired crease patterns were applied to the cellulose scaffolds in order to introduce directional flexibility beneficial for cardiac contraction. The transfer of a Miura-ori crease pattern was successfully applied in two ways: folding of the dried sheet between PET foils pre-formed in a 3D printed mold, and in situ wet fiber molding on a 3D-patterned mesh mounted in the sheet former’s sieve section. The latter approach enables upscaling for potential mass production.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    Enhanced formation of nanometric titanium cones by incorporation of titanium, tungsten and/or iron in a helium ion beam
    (Elsevier, 12/2022) Sanchez, Fabien; Steiner, Roland; Latttner, P.; Spicher, J.; Mathys, Daniel; Antunes, Rodrigo; Marcin, Kisiel; Mukkadam, Khaled; Astasov-Fraunhofer, Monika; Kühl, Sebastian; Köser, Joachim; Wagner, Raphael; Marot, Laurent; Meyer, Ernst [in: Surfaces and Interfaces]
    Surface patterning of bio-compatible titanium (Ti) shows a growing interest in the medical field. The engineering of material surfaces can achieve bactericidal properties and osteointegration improvements in order to develop medical implants. Spikes-like surface morphologies have already demonstrated the development of promising bactericidal properties. A barely new method to produce nanometric-sized cones on titanium consists of helium (He) ion irradiation using low energies ( 100 eV) and temperatures comprised between 0.25 T/T 0.5 (with T being the melting temperature of the material). Ti, iron (Fe) and/or tungsten (W) were incorporated in a He beam, and their amounts were quantified using X-ray Photoelectron Spectroscopy (XPS). The He ion energy was varied from 70 and 120 eV, the surface temperatures from 571 to 651 K for fluences approximately equal to 1024 m−2. After irradiation, the surface morphology was characterized using Scanning Electron Microscopy (SEM) and Focused Ion Beam (FIB). This study demonstrated the capability for irradiated Ti surfaces to form cones with tunable density, aspect ratio, and heights with the incorporation of Ti, Fe and/or W in a He ion. Additionally, the growth rate of the cones was enhanced by about 30 times in comparison to pure He irradiation as a function of the chosen materials introduced in the He beam.
    01A - Beitrag in wissenschaftlicher Zeitschrift