TY  - JOUR
A1  - Haider, Malik Salman
A1  - Ahmad, Taufiq
A1  - Yang, Mengshi
A1  - Hu, Chen
A1  - Hahn, Lukas
A1  - Stahlhut, Philipp
A1  - Groll, Jürgen
A1  - Luxenhofer, Robert
T1  - Tuning the thermogelation and rheology of poly(2-oxazoline)/poly(2-oxazine)s based thermosensitive hydrogels for 3D bioprinting
JF  - Gels
N2  - As one kind of “smart” material, thermogelling polymers find applications in biofabrication, drug delivery and regenerative medicine. In this work, we report a thermosensitive poly(2-oxazoline)/poly(2-oxazine) based diblock copolymer comprising thermosensitive/moderately hydrophobic poly(2-N-propyl-2-oxazine) (pPrOzi) and thermosensitive/moderately hydrophilic poly(2-ethyl-2-oxazoline) (pEtOx). Hydrogels were only formed when block length exceeded certain length (≈100 repeat units). The tube inversion and rheological tests showed that the material has then a reversible sol-gel transition above 25 wt.% concentration. Rheological tests further revealed a gel strength around 3 kPa, high shear thinning property and rapid shear recovery after stress, which are highly desirable properties for extrusion based three-dimensional (3D) (bio) printing. Attributed to the rheology profile, well resolved printability and high stackability (with added laponite) was also possible. (Cryo) scanning electron microscopy exhibited a highly porous, interconnected, 3D network. The sol-state at lower temperatures (in ice bath) facilitated the homogeneous distribution of (fluorescently labelled) human adipose derived stem cells (hADSCs) in the hydrogel matrix. Post-printing live/dead assays revealed that the hADSCs encapsulated within the hydrogel remained viable (≈97%). This thermoreversible and (bio) printable hydrogel demonstrated promising properties for use in tissue engineering applications.
KW  - poly(2-ethyl-2-oxazoline)
KW  - shear thinning
KW  - shape fidelity
KW  - cyto-compatibility
KW  - bio-printability
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-241781
SN  - 2310-2861
VL  - 7
IS  - 3
ER  - 
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  -