@article{JanzenBakirciFaberetal.2022,
  author    = {Janzen, Dieter and Bakirci, Ezgi and Faber, Jessica and Andrade Mier, Mateo and Hauptstein, Julia and Pal, Arindam and Forster, Leonard and Hazur, Jonas and Boccaccini, Aldo R. and Detsch, Rainer and Teßmar, J{\"o}rg and Budday, Silvia and Blunk, Torsten and Dalton, Paul D. and Villmann, Carmen},
  title     = {Reinforced Hyaluronic Acid-Based Matrices Promote 3D Neuronal Network Formation},
  series = {Advanced Healthcare Materials},
  volume    = {11},
  journal   = {Advanced Healthcare Materials},
  number    = {21},
  doi       = {10.1002/adhm.202201826},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-318682},
  year      = {2022},
  abstract  = {3D neuronal cultures attempt to better replicate the in vivo environment to study neurological/neurodegenerative diseases compared to 2D models. A challenge to establish 3D neuron culture models is the low elastic modulus (30-500 Pa) of the native brain. Here, an ultra-soft matrix based on thiolated hyaluronic acid (HA-SH) reinforced with a microfiber frame is formulated and used. Hyaluronic acid represents an essential component of the brain extracellular matrix (ECM). Box-shaped frames with a microfiber spacing of 200 µm composed of 10-layers of poly(ɛ-caprolactone) (PCL) microfibers (9.7 ± 0.2 µm) made via melt electrowriting (MEW) are used to reinforce the HA-SH matrix which has an elastic modulus of 95 Pa. The neuronal viability is low in pure HA-SH matrix, however, when astrocytes are pre-seeded below this reinforced construct, they significantly support neuronal survival, network formation quantified by neurite length, and neuronal firing shown by Ca\(^{2+}\) imaging. The astrocyte-seeded HA-SH matrix is able to match the neuronal viability to the level of Matrigel, a gold standard matrix for neuronal culture for over two decades. Thus, this 3D MEW frame reinforced HA-SH composite with neurons and astrocytes constitutes a reliable and reproducible system to further study brain diseases.},
  language  = {en}
}
@article{SchmidSchmidtHazuretal.2020,
  author    = {Schmid, Rafael and Schmidt, Sonja K. and Hazur, Jonas and Detsch, Rainer and Maurer, Evelyn and Boccaccini, Aldo R. and Hauptstein, Julia and Teßmar, J{\"o}rg and Blunk, Torsten and Schr{\"u}fer, Stefan and Schubert, Dirk W. and Horch, Raymund E. and Bosserhoff, Anja K. and Arkudas, Andreas and Kengelbach-Weigand, Annika},
  title     = {Comparison of hydrogels for the development of well-defined 3D cancer models of breast cancer and melanoma},
  series = {Cancers},
  volume    = {12},
  journal   = {Cancers},
  number    = {8},
  issn      = {2072-6694},
  doi       = {10.3390/cancers12082320},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-211195},
  year      = {2020},
  abstract  = {Bioprinting offers the opportunity to fabricate precise 3D tumor models to study tumor pathophysiology and progression. However, the choice of the bioink used is important. In this study, cell behavior was studied in three mechanically and biologically different hydrogels (alginate, alginate dialdehyde crosslinked with gelatin (ADA-GEL), and thiol-modified hyaluronan (HA-SH crosslinked with PEGDA)) with cells from breast cancer (MDA-MB-231 and MCF-7) and melanoma (Mel Im and MV3), by analyzing survival, growth, and the amount of metabolically active, living cells via WST-8 labeling. Material characteristics were analyzed by dynamic mechanical analysis. Cell lines revealed significantly increased cell numbers in low-percentage alginate and HA-SH from day 1 to 14, while only Mel Im also revealed an increase in ADA-GEL. MCF-7 showed a preference for 1\% alginate. Melanoma cells tended to proliferate better in ADA-GEL and HA-SH than mammary carcinoma cells. In 1\% alginate, breast cancer cells showed equally good proliferation compared to melanoma cell lines. A smaller area was colonized in high-percentage alginate-based hydrogels. Moreover, 3\% alginate was the stiffest material, and 2.5\% ADA-GEL was the softest material. The other hydrogels were in the same range in between. Therefore, cellular responses were not only stiffness-dependent. With 1\% alginate and HA-SH, we identified matrices that enable proliferation of all tested tumor cell lines while maintaining expected tumor heterogeneity. By adapting hydrogels, differences could be accentuated. This opens up the possibility of understanding and analyzing tumor heterogeneity by biofabrication.},
  language  = {en}
}
@article{HazurDetschKarakayaetal.2020,
  author    = {Hazur, Jonas and Detsch, Rainer and Karakaya, Emine and Kaschta, Joachim and Teßmar, J{\"o}rg and Schneidereit, Dominik and Friedrich, Oliver and Schubert, Dirk W and Boccaccini, Aldo R},
  title     = {Improving alginate printability for biofabrication: establishment of a universal and homogeneous pre-crosslinking technique},
  series = {Biofabrication},
  volume    = {12},
  journal   = {Biofabrication},
  number    = {4},
  doi       = {10.1088/1758-5090/ab98e5},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-254030},
  year      = {2020},
  abstract  = {Many different biofabrication approaches as well as a variety of bioinks have been developed by researchers working in the field of tissue engineering. A main challenge for bioinks often remains the difficulty to achieve shape fidelity after printing. In order to overcome this issue, a homogeneous pre-crosslinking technique, which is universally applicable to all alginate-based materials, was developed. In this study, the Young's Modulus after post-crosslinking of selected hydrogels, as well as the chemical characterization of alginate in terms of M/G ratio and molecular weight, were determined. With our technique it was possible to markedly enhance the printability of a 2\% (w/v) alginate solution, without using a higher polymer content, fillers or support structures. 3D porous scaffolds with a height of around 5 mm were printed. Furthermore, the rheological behavior of different pre-crosslinking degrees was studied. Shear forces on cells as well as the flow profile of the bioink inside the printing nozzle during the process were estimated. A high cell viability of printed NIH/3T3 cells embedded in the novel bioink of more than 85\% over a time period of two weeks could be observed.},
  language  = {en}
}