h1

%0 Thesis
%A Möhl, Ninon
%T Synthetic anisotropic multiphasic hydrogels for in vitro tissue models
%I RWTH Aachen University
%V Dissertation
%C Aachen
%M RWTH-2026-00387
%P 1 Online-Ressource : Illustrationen
%D 2025
%Z Veröffentlicht auf dem Publikationsserver der RWTH Aachen University 2026
%Z Dissertation, RWTH Aachen University, 2025
%X The regeneration of complex, hierarchically organized native tissue and organs requires approaches that can provide directional guidance for cells. While most injectable hydrogels enable minimally invasive delivery and adaptable properties such as stiffness and degradation cues, they remain mostly isotropic and do not present cellular guidance cues. To overcome this limitation, multiphasic anisotropic hydrogels have been developed, employing external triggers (electrical, light, sound, or magnetic stimuli) or mechanical deposition. One emerging approach involves the use of rod-shaped microgels as tissue engineering building blocks. They offer injectability, porosity, and biochemical functionality to guide cells in three-dimensional (3D) tissue engineering constructs. A fully synthetic 3D kidney disease model designed to overcome current limitations in in vitro systems was developed. Current kidney organoid or microfluidic platforms lack mature tissue development, scalability, and control over spatial organization. Our platform is composed of a compartmentalized poly(ethylene glycol) (PEG)-based hydrogel matrix comprising anisometric PEG microgels that enable structural organization of a triple co-culture of key renal cell types, including epithelial cells (CD10<sup>+</sup>), endothelial cells (CD31<sup>+</sup>), and pericytes (PDGFRβ<sup>+</sup>). The functionality of our model was validated by inducing fibrosis through TGFβ, highlighting the potential of this system as a scalable and tunable disease model. Furthermore, a robust and scalable method has been established to produce degradable rod microgels in a microfluidic high-throughput manner. Here, a combinative approach of step-emulsification followed by consecutive droplet distribution and confinement on a single microfluidic device was developed. The potential and feasibility of the microfluidic design are highlighted by using two photo-initiated PEG-based polymerization chemistries and comparing them side by side. Furthermore, we report advances using compartmentalized jet polymerization, a microfluidic technique that now enables the continuous production of rod microgels with adjustable stiffness, aspect ratios, and sizes as small as 3 µm. These ultra-thin rod microgels can be rendered magnetic using a novel post-functionalization protocol developed in this thesis. Additionally, this method is used to produce ultra-soft and porous variants with pore sizes in the range of 2–5 µm. Both microgel types were employed in cell experiments, showing promising results when integrated as magneto-responsive microgels inside an Anisogel or as 3D cell-assembled tissue constructs. Finally, this thesis introduces an alternative cross-linking approach to the elastic hydrogel matrix used for the Anisogel system. A PEG-based hydrogel cross-linked through dynamic covalent bonds is synthesized and analyzed. Different polymer architectures were compared and their influence on the hydrogel properties assessed. Furthermore, different biocompatible catalysts are introduced to enhance the reaction kinetics at physiological pH making this hydrogel matrix promising for future cell experiments.
%F PUB:(DE-HGF)11
%9 Dissertation / PhD Thesis
%R 10.18154/RWTH-2026-00387
%U https://publications.rwth-aachen.de/record/1024868