TY  - JOUR
A1  - Borova, Solomiia
A1  - Tokarev, Victor
A1  - Stahlhut, Philipp
A1  - Luxenhofer, Robert
T1  - Crosslinking of hydrophilic polymers using polyperoxides
JF  - Colloid and Polymer Science
N2  - Hydrogels that can mimic mechanical properties and functions of biological tissue have attracted great interest in tissue engineering and biofabrication. In these fields, new materials and approaches to prepare hydrogels without using toxic starting materials or materials that decompose into toxic compounds remain to be sought after. Here, we report the crosslinking of commercial, unfunctionalized hydrophilic poly(2-ethyl-2-oxazoline) using peroxide copolymers in their melt. The influence of temperature, peroxide copolymer concentration, and duration of the crosslinking process has been investigated. The method allows to create hydrogels from unfunctionalized polymers in their melt and to control the mechanical properties of the resulting materials. The design of hydrogels with a suitable mechanical performance is of crucial importance in many existing and potential applications of soft materials, including medical applications.
KW  - hydrogels
KW  - radical crosslinking
KW  - poly(2-ethyl-2-oxazoline)
KW  - thermal crosslinking
KW  - peroxide containing copolymers
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-238109
VL  - 298
ER  - 
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  -