TY  - JOUR
A1  - Borova, Solomiia
A1  - Schlutt, Christine
A1  - Nickel, Joachim
A1  - Luxenhofer, Robert
T1  - A Transient Initiator for Polypeptoids Postpolymerization α‐Functionalization via Activation of a Thioester Group
JF  - Macromolecular Chemistry and Physics
N2  - Here, a postpolymerization modification method for an α-terminal functionalized poly-(N-methyl-glycine), also known as polysarcosine, is introduced. 4-(Methylthio)phenyl piperidine-4-carboxylate as an initiator for the ring-opening polymerization of N-methyl-glycine-N-carboxyanhydride followed by oxidation of the thioester group to yield an α-terminal reactive 4-(methylsulfonyl)phenyl piperidine-4-carboxylate polymer is utilized. This represents an activated carboxylic acid terminus, allowing straightforward modification with nucleophiles under mild reaction conditions and provides the possibility to introduce a wide variety of nucleophiles as exemplified using small molecules, fluorescent dyes, and model proteins. The new initiator yielded polymers with well-defined molar mass, low dispersity, and high end-group fidelity, as observed by gel permeation chromatography, nuclear magnetic resonance spectroscopy, and matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy. The introduced method can be of great interest for bioconjugation, but requires optimization, especially for protein conjugation.
KW  - ring-opening polymerization
KW  - bioconjugation
KW  - functional initiators
KW  - polypeptoids
KW  - postpolymerization modification
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-257587
VL  - 223
IS  - 3
ER  - 
TY  - JOUR
A1  - Kress, Sebastian
A1  - Baur, Johannes
A1  - Otto, Christoph
A1  - Burkard, Natalie
A1  - Braspenning, Joris
A1  - Walles, Heike
A1  - Nickel, Joachim
A1  - Metzger, Marco
T1  - Evaluation of a miniaturized biologically vascularized scaffold in vitro and in vivo
JF  - Scientific Reports
N2  - In tissue engineering, the generation and functional maintenance of dense voluminous tissues is mainly restricted due to insufficient nutrient supply. Larger three-dimensional constructs, which exceed the nutrient diffusion limit become necrotic and/or apoptotic in long-term culture if not provided with an appropriate vascularization. Here, we established protocols for the generation of a pre-vascularized biological scaffold with intact arterio-venous capillary loops from rat intestine, which is decellularized under preservation of the feeding and draining vascular tree. Vessel integrity was proven by marker expression, media/blood reflow and endothelial LDL uptake. In vitro maintenance persisted up to 7 weeks in a bioreactor system allowing a stepwise reconstruction of fully vascularized human tissues and successful in vivo implantation for up to 4 weeks, although with time-dependent decrease of cell viability. The vascularization of the construct lead to a 1.5× increase in cellular drug release compared to a conventional static culture in vitro. For the first time, we performed proof-of-concept studies demonstrating that 3D tissues can be maintained within a miniaturized vascularized scaffold in vitro and successfully implanted after re-anastomosis to the intrinsic blood circulation in vivo. We hypothesize that this technology could serve as a powerful platform technology in tissue engineering and regenerative medicine.
KW  - biological models
KW  - translational research
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176343
VL  - 8
IS  - 4719
ER  -