32 Hansen, Nadja Fischer, Horst Jockenhövel, Stefan 542000-2 ; 937710 520000 RWTH Aachen University Aachen German 1 Online-Ressource : Illustrationen The present work describes the development of a novel 3D-bioprinted in vitro model of a blood vessel to provide new insights into the mechanisms of tissue angiogenesis and to test new drug substances. A bioreactor made of PEEK was developed, which enables direct imaging and perfusion. Furthermore, different collagen- and fibrin-based hydrogels were tailored to the different cell types, compared with each other and the cell-ECM interactions were studied. The results show the benefit of pure 2.5 % fibrin for obtaining a stable endothelial layer as a lining for the 3D-bioprinted macrovessels. In contrast, collagen-fibrin compositions with larger pores and less stiffness were particularly suitable for tissue models of the liver and as matrices of tumor spheroids. In particular, hepatocytes showed an increased metabolic activity by an increased production of albumin in the hydrogel that corresponded to the stiffness of the healthy liver (4.5 kPa). It was also shown, that the introduction of fibroblast and HUVECs into the matrix had a positive influence on cell adhesion and metabolism. HUVECs in the surrounding matrix increased the formation of microvessels from the printed macrovessel. It was advantageous if the printed HUVECs were first cultured in the gelatine for three hours to adhere to the surrounding matrix, before the gel was rinsed out. The endothelial layer was significantly more stable if it had 72 hours to form under static conditions before the flow through and thus the dynamic cultivation started. Using the double sacrificial material method, branched vascular structures up to a diameter of 10 µm could be produced. The combination of the developed in vitro model with a further developed liver and the tumor model could provide new insights into the metastatic cascade and subsequently for new approaches for cancer therapy. Veröffentlicht auf dem Publikationsserver der RWTH Aachen University 2026 ; Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2025 ; 2, ; PUB:(DE-HGF)11, ; Dissertation / PhD Thesis Dissertation Rheinisch-Westfälische Technische Hochschule Aachen 2025 2025 RWTH-2025-08995 2025 https://publications.rwth-aachen.de/record/1020439