TY  - JOUR
A1  - Hazur, Jonas
A1  - Detsch, Rainer
A1  - Karakaya, Emine
A1  - Kaschta, Joachim
A1  - Teßmar, Jörg
A1  - Schneidereit, Dominik
A1  - Friedrich, Oliver
A1  - Schubert, Dirk W
A1  - Boccaccini, Aldo R
T1  - Improving alginate printability for biofabrication: establishment of a universal and homogeneous pre-crosslinking technique
JF  - Biofabrication
N2  - 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.
KW  - alginate
KW  - bioprinting
KW  - rheology
KW  - bioink
KW  - pre-crosslinking
KW  - printability
KW  - shape fidelity
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-254030
VL  - 12
IS  - 4
ER  - 
TY  - JOUR
A1  - Ryma, Matthias
A1  - Genç, Hatice
A1  - Nadernezhad, Ali
A1  - Paulus, Ilona
A1  - Schneidereit, Dominik
A1  - Friedrich, Oliver
A1  - Andelovic, Kristina
A1  - Lyer, Stefan
A1  - Alexiou, Christoph
A1  - Cicha, Iwona
A1  - Groll, Jürgen
T1  - A Print-and-Fuse Strategy for Sacrificial Filaments Enables Biomimetically Structured Perfusable Microvascular Networks with Functional Endothelium Inside 3D Hydrogels
JF  - Advanced Materials
N2  - A facile and flexible approach for the integration of biomimetically branched microvasculature within bulk hydrogels is presented. For this, sacrificial scaffolds of thermoresponsive poly(2-cyclopropyl-2-oxazoline) (PcycloPrOx) are created using melt electrowriting (MEW) in an optimized and predictable way and subsequently placed into a customized bioreactor system, which is then filled with a hydrogel precursor solution. The aqueous environment above the lower critical solution temperature (LCST) of PcycloPrOx at 25 °C swells the polymer without dissolving it, resulting in fusion of filaments that are deposited onto each other (print-and-fuse approach). Accordingly, an adequate printing pathway design results in generating physiological-like branchings and channel volumes that approximate Murray's law in the geometrical ratio between parent and daughter vessels. After gel formation, a temperature decrease below the LCST produces interconnected microchannels with distinct inlet and outlet regions. Initial placement of the sacrificial scaffolds in the bioreactors in a pre-defined manner directly yields perfusable structures via leakage-free fluid connections in a reproducible one-step procedure. Using this approach, rapid formation of a tight and biologically functional endothelial layer, as assessed not only through fluorescent dye diffusion, but also by tumor necrosis factor alpha (TNF-α) stimulation, is obtained within three days.
KW  - hydrogels
KW  - microvasculature
KW  - melt electrowriting
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-318532
VL  - 34
IS  - 28
ER  -