TY  - JOUR
A1  - Mechau, Jannik
A1  - Frank, Andreas
A1  - Bakirci, Ezgi
A1  - Gumbel, Simon
A1  - Jungst, Tomasz
A1  - Giesa, Reiner
A1  - Groll, Jürgen
A1  - Dalton, Paul D.
A1  - Schmidt, Hans‐Werner
T1  - Hydrophilic (AB)\(_{n}\) Segmented Copolymers for Melt Extrusion‐Based Additive Manufacturing
JF  - Macromolecular Chemistry and Physics
N2  - Several manufacturing technologies beneficially involve processing from the melt, including extrusion‐based printing, electrospinning, and electrohydrodynamic jetting. In this study, (AB)\(_{n}\) segmented copolymers are tailored for melt‐processing to form physically crosslinked hydrogels after swelling. The copolymers are composed of hydrophilic poly(ethylene glycol)‐based segments and hydrophobic bisurea segments, which form physical crosslinks via hydrogen bonds. The degree of polymerization was adjusted to match the melt viscosity to the different melt‐processing techniques. Using extrusion‐based printing, a width of approximately 260 µm is printed into 3D constructs, with excellent interlayer bonding at fiber junctions, due to hydrogen bonding between the layers. For melt electrospinning, much thinner fibers in the range of about 1–15 µm are obtained and produced in a typical nonwoven morphology. With melt electrowriting, fibers are deposited in a controlled way to well‐defined 3D constructs. In this case, multiple fiber layers fuse together enabling constructs with line width in the range of 70 to 160 µm. If exposed to water the printed constructs swell and form physically crosslinked hydrogels that slowly disintegrate, which is a feature for soluble inks within biofabrication strategies. In this context, cytotoxicity tests confirm the viability of cells and thus demonstrating biocompatibility of this class of copolymers.
KW  - 3D printing
KW  - (AB)\(_{n}\) segmented copolymers
KW  - biocompatibility
KW  - melt electrowriting
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-224513
VL  - 222
IS  - 1
ER  - 
TY  - JOUR
A1  - Hrynevich, Andrei
A1  - Achenbach, Pascal
A1  - Jungst, Tomasz
A1  - Brook, Gary A.
A1  - Dalton, Paul D.
T1  - Design of Suspended Melt Electrowritten Fiber Arrays for Schwann Cell Migration and Neurite Outgrowth
JF  - Macromolecular Bioscience
N2  - In this study, well-defined, 3D arrays of air-suspended melt electrowritten fibers are made from medical grade poly(ɛ-caprolactone) (PCL). Low processing temperatures, lower voltages, lower ambient temperature, increased collector distance, and high collector speeds all aid to direct-write suspended fibers that can span gaps of several millimeters between support structures. Such processing parameters are quantitatively determined using a “wedge-design” melt electrowritten test frame to identify the conditions that increase the suspension probability of long-distance fibers. All the measured parameters impact the probability that a fiber is suspended over multimillimeter distances. The height of the suspended fibers can be controlled by a concurrently fabricated fiber wall and the 3D suspended PCL fiber arrays investigated with early post-natal mouse dorsal root ganglion explants. The resulting Schwann cell and neurite outgrowth extends substantial distances by 21 d, following the orientation of the suspended fibers and the supporting walls, often generating circular whorls of high density Schwann cells between the suspended fibers. This research provides a design perspective and the fundamental parametric basis for suspending individual melt electrowritten fibers into a form that facilitates cell culture.
KW  - cell migration
KW  - electrospinning
KW  - fibers
KW  - neurite growth
KW  - polycaprolactone
KW  - tissue engineering
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-257535
VL  - 21
IS  - 7
ER  -