@article{KowalewiczVorndranFeichtneretal.2021,
  author    = {Kowalewicz, Katharina and Vorndran, Elke and Feichtner, Franziska and Waselau, Anja-Christina and Brueckner, Manuel and Meyer-Lindenberg, Andrea},
  title     = {In-vivo degradation behavior and osseointegration of 3D powder-printed calcium magnesium phosphate cement scaffolds},
  series = {Materials},
  volume    = {14},
  journal   = {Materials},
  number    = {4},
  issn      = {1996-1944},
  doi       = {10.3390/ma14040946},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-228929},
  year      = {2021},
  abstract  = {Calcium magnesium phosphate cements (CMPCs) are promising bone substitutes and experience great interest in research. Therefore, in-vivo degradation behavior, osseointegration and biocompatibility of three-dimensional (3D) powder-printed CMPC scaffolds were investigated in the present study. The materials Mg225 (Ca\(_{0.75}\)Mg\(_{2.25}\)(PO\(_4\))\(_2\)) and Mg225d (Mg225 treated with diammonium hydrogen phosphate (DAHP)) were implanted as cylindrical scaffolds (h = 5 mm, {\O} = 3.8 mm) in both lateral femoral condyles in rabbits and compared with tricalcium phosphate (TCP). Treatment with DAHP results in the precipitation of struvite, thus reducing pore size and overall porosity and increasing pressure stability. Over 6 weeks, the scaffolds were evaluated clinically, radiologically, with Micro-Computed Tomography (µCT) and histological examinations. All scaffolds showed excellent biocompatibility. X-ray and in-vivo µCT examinations showed a volume decrease and increasing osseointegration over time. Structure loss and volume decrease were most evident in Mg225. Histologically, all scaffolds degraded centripetally and were completely traversed by new bone, in which the remaining scaffold material was embedded. While after 6 weeks, Mg225d and TCP were still visible as a network, only individual particles of Mg225 were present. Based on these results, Mg225 and Mg225d appear to be promising bone substitutes for various loading situations that should be investigated further.},
  language  = {en}
}
@article{MechauFrankBakircietal.2021,
  author    = {Mechau, Jannik and Frank, Andreas and Bakirci, Ezgi and Gumbel, Simon and Jungst, Tomasz and Giesa, Reiner and Groll, J{\"u}rgen and Dalton, Paul D. and Schmidt, Hans-Werner},
  title     = {Hydrophilic (AB)\(_{n}\) Segmented Copolymers for Melt Extrusion-Based Additive Manufacturing},
  series = {Macromolecular Chemistry and Physics},
  volume    = {222},
  journal   = {Macromolecular Chemistry and Physics},
  number    = {1},
  doi       = {10.1002/macp.202000265},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-224513},
  year      = {2021},
  abstract  = {Several manufacturing technologies beneficially involve processing from the melt, including extrusion-based printing, electrospinning, and electrohydrodynamic jetting. In this study, (AB)\(_{n}\) segmented copolymers are tailored for melt-processing to form physically crosslinked hydrogels after swelling. The copolymers are composed of hydrophilic poly(ethylene glycol)-based segments and hydrophobic bisurea segments, which form physical crosslinks via hydrogen bonds. The degree of polymerization was adjusted to match the melt viscosity to the different melt-processing techniques. Using extrusion-based printing, a width of approximately 260 µm is printed into 3D constructs, with excellent interlayer bonding at fiber junctions, due to hydrogen bonding between the layers. For melt electrospinning, much thinner fibers in the range of about 1-15 µm are obtained and produced in a typical nonwoven morphology. With melt electrowriting, fibers are deposited in a controlled way to well-defined 3D constructs. In this case, multiple fiber layers fuse together enabling constructs with line width in the range of 70 to 160 µm. If exposed to water the printed constructs swell and form physically crosslinked hydrogels that slowly disintegrate, which is a feature for soluble inks within biofabrication strategies. In this context, cytotoxicity tests confirm the viability of cells and thus demonstrating biocompatibility of this class of copolymers.},
  language  = {en}
}