@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} } @article{LiashenkoHrynevichDalton2020, author = {Liashenko, Ievgenii and Hrynevich, Andrei and Dalton, Paul D.}, title = {Designing Outside the Box: Unlocking the Geometric Freedom of Melt Electrowriting using Microscale Layer Shifting}, series = {Advanced Materials}, volume = {32}, journal = {Advanced Materials}, number = {28}, doi = {10.1002/adma.202001874}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-217974}, year = {2020}, abstract = {Melt electrowriting, a high-resolution additive manufacturing technology, has so far been developed with vertical stacking of fiber layers, with a printing trajectory that is constant for each layer. In this work, microscale layer shifting is introduced through deliberately offsetting the printing trajectory for each printed layer. Inaccuracies during the printing of sinusoidal walls are corrected via layer shifting, resulting in accurate control of their geometry and mechanical properties. Furthermore, more substantial layer shifting allows stacking of fiber layers in a horizontal manner, overcoming the electrostatic autofocusing effect that favors vertical layer stacking. Novel nonlinear geometries, such as overhangs, wall texturing and branching, and smooth and abrupt changes in printing trajectory are presented, demonstrating the flexibility of the layer shifting approach beyond the state-of-the-art. The practice of microscale layer shifting for melt electrowriting enables more complex geometries that promise to have a profound impact on the development of products in a broad range of applications.}, language = {en} }