@article{JanzenBakirciWielandetal.2020,
  author    = {Janzen, Dieter and Bakirci, Ezgi and Wieland, Annalena and Martin, Corinna and Dalton, Paul D. and Villmann, Carmen},
  title     = {Cortical Neurons form a Functional Neuronal Network in a 3D Printed Reinforced Matrix},
  series = {Advanced Healthcare Materials},
  volume    = {9},
  journal   = {Advanced Healthcare Materials},
  number    = {9},
  doi       = {10.1002/adhm.201901630},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-215400},
  year      = {2020},
  abstract  = {Impairments in neuronal circuits underly multiple neurodevelopmental and neurodegenerative disorders. 3D cell culture models enhance the complexity of in vitro systems and provide a microenvironment closer to the native situation than with 2D cultures. Such novel model systems will allow the assessment of neuronal network formation and their dysfunction under disease conditions. Here, mouse cortical neurons are cultured from embryonic day E17 within in a fiber-reinforced matrix. A soft Matrigel with a shear modulus of 31 ± 5.6 Pa is reinforced with scaffolds created by melt electrowriting, improving its mechanical properties and facilitating the handling. Cortical neurons display enhance cell viability and the neuronal network maturation in 3D, estimated by staining of dendrites and synapses over 21 days in vitro, is faster in 3D compared to 2D cultures. Using functional readouts with electrophysiological recordings, different firing patterns of action potentials are observed, which are absent in the presence of the sodium channel blocker, tetrodotoxin. Voltage-gated sodium currents display a current-voltage relationship with a maximum peak current at -25 mV. With its high customizability in terms of scaffold reinforcement and soft matrix formulation, this approach represents a new tool to study neuronal networks in 3D under normal and, potentially, disease conditions.},
  language  = {en}
}
@article{CastilhoHochleitnerWilsonetal.2018,
  author    = {Castilho, Miguel and Hochleitner, Gernot and Wilson, Wouter and van Rietbergen, Bert and Dalton, Paul D. and Groll, J{\"u}rgen and Malda, Jos and Ito, Keita},
  title     = {Mechanical behavior of a soft hydrogel reinforced with three-dimensional printed microfibre scaffolds},
  series = {Scientific Reports},
  volume    = {8},
  journal   = {Scientific Reports},
  doi       = {10.1038/s41598-018-19502-y},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-222280},
  year      = {2018},
  abstract  = {Reinforcing hydrogels with micro-fibre scaffolds obtained by a Melt-Electrospinning Writing (MEW) process has demonstrated great promise for developing tissue engineered (TE) constructs with mechanical properties compatible to native tissues. However, the mechanical performance and reinforcement mechanism of the micro-fibre reinforced hydrogels is not yet fully understood. In this study, FE models, implementing material properties measured experimentally, were used to explore the reinforcement mechanism of fibre-hydrogel composites. First, a continuum FE model based on idealized scaffold geometry was used to capture reinforcement effects related to the suppression of lateral gel expansion by the scaffold, while a second micro-FE model based on micro-CT images of the real construct geometry during compaction captured the effects of load transfer through the scaffold interconnections. Results demonstrate that the reinforcement mechanism at higher scaffold volume fractions was dominated by the load carrying-ability of the fibre scaffold interconnections, which was much higher than expected based on testing scaffolds alone because the hydrogel provides resistance against buckling of the scaffold. We propose that the theoretical understanding presented in this work will assist the design of more effective composite constructs with potential applications in a wide range of TE conditions.},
  language  = {en}
}
@article{KotzRischArnoldetal.2019,
  author    = {Kotz, Frederik and Risch, Patrick and Arnold, Karl and Sevim, Semih and Puigmart{\´i}-Luis, Josep and Quick, Alexander and Thiel, Michael and Hrynevich, Andrei and Dalton, Paul D. and Helmer, Dorothea and Rapp, Bastian E.},
  title     = {Fabrication of arbitrary three-dimensional suspended hollow microstructures in transparent fused silica glass},
  series = {Nature Communications},
  volume    = {10},
  journal   = {Nature Communications},
  doi       = {10.1038/s41467-019-09497-z},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-224787},
  year      = {2019},
  abstract  = {Fused silica glass is the preferred material for applications which require long-term chemical and mechanical stability as well as excellent optical properties. The manufacturing of complex hollow microstructures within transparent fused silica glass is of particular interest for, among others, the miniaturization of chemical synthesis towards more versatile, configurable and environmentally friendly flow-through chemistry as well as high-quality optical waveguides or capillaries. However, microstructuring of such complex three-dimensional structures in glass has proven evasive due to its high thermal and chemical stability as well as mechanical hardness. Here we present an approach for the generation of hollow microstructures in fused silica glass with high precision and freedom of three-dimensional designs. The process combines the concept of sacrificial template replication with a room-temperature molding process for fused silica glass. The fabricated glass chips are versatile tools for, among other, the advance of miniaturization in chemical synthesis on chip.},
  language  = {en}
}
@article{TylekBlumHrynevichetal.2020,
  author    = {Tylek, Tina and Blum, Carina and Hrynevich, Andrei and Schlegelmilch, Katrin and Schilling, Tatjana and Dalton, Paul D and Groll, J{\"u}rgen},
  title     = {Precisely defined fiber scaffolds with 40 μm porosity induce elongation driven M2-like polarization of human macrophages},
  series = {Biofabrication},
  volume    = {12},
  journal   = {Biofabrication},
  number    = {2},
  doi       = {10.1088/1758-5090/ab5f4e},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-254012},
  year      = {2020},
  abstract  = {Macrophages are key players of the innate immune system that can roughly be divided into the pro-inflammatory M1 type and the anti-inflammatory, pro-healing M2 type. While a transient initial pro-inflammatory state is helpful, a prolonged inflammation deteriorates a proper healing and subsequent regeneration. One promising strategy to drive macrophage polarization by biomaterials is precise control over biomaterial geometry. For regenerative approaches, it is of particular interest to identify geometrical parameters that direct human macrophage polarization. For this purpose, we advanced melt electrowriting (MEW) towards the fabrication of fibrous scaffolds with box-shaped pores and precise inter-fiber spacing from 100 μm down to only 40 μm. These scaffolds facilitate primary human macrophage elongation accompanied by differentiation towards the M2 type, which was most pronounced for the smallest pore size of 40 μm. These new findings can be important in helping to design new biomaterials with an enhanced positive impact on tissue regeneration.},
  language  = {en}
}