Fabrication of hollow 3D tissue models with drop-on-demand bioprinting and controlled cellular self-assembly

Abstract: The present work describes processes for the fabrication of three-dimensional (3D) tubular cell constructs and their structural and functional characterization and application. Drop-on-demand (DoD) bioprinting is applied as fabrication technology and controlled cellular self-assembly is integrated into the process as a novel concept. The developed bioink consists of a cell suspension with Fibrinogen as the carrier fluid. The DoD technology allows the deposition of single droplets (V ~ 10 nl) of the bioink (N(cx) = 10, 50, 100, 150, and 250 cells/droplet) at defined voxels to generate spatially defined cell clusters (down to widths w = 180 ± 10 μm). With an overlap droplet deposition (φ = 1.35), the single clusters can be combined to form continuous line designs of arbitrary shapes. These cell clusters are embedded layer-by-layer in a 3D hydrogel scaffold (Collagen I, Matrigel, and Fibrin), representing the initial state. Fibrinogen was found to be an essential component in the bioink to maintain the shape of the patterns during embedding, as it is cross-linked post-deposition, and the structure can thus be preserved. A suitable combination of the involved materials and bioink formulation subsequently enables the controlled self-assembly of the cells, leading to the intrinsic maturation towards the final structure over time. Compared to the initial state, the final structure shows increased structural and functional complexity.
The process can be applied to model vessel-like tissue structures. Such models are recognized as spheroids or tubules, each comprising a lumen surrounded by a closed cell layer. By choosing appropriate cell types, kidney tubules (nephrons) are modeled from two types of epithelial cells. In detail, epithelial spheroids with defined diameters (Ø = 84, 104, 120, and 131 μm) can be generated in large numbers and embedded at defined positions (arrays) in a 3D hydrogel. With the previous state-of-the-art, spheroids could only be generated with randomized size distribution and at arbitrary positions in a hydrogel.
In contrast to known fabrication methods of tubular constructs, this concept does not require prefabrication of channels, which are then populated with cells. Here, the tubular structure is formed by an intrinsic reorganization of the cells. This allows the realization of smaller, more physiological tubule diameters down to Ø = 98 ± 13 μm in one continuous fabrication process. The fabricated tubules can be integrated into fluidic perfusion channels as organ-on-a-chip, and the lumen contacted to generate physiological flow conditions (shear stress τ = 0.4 dyne/cm²) within the lumen by hydrostatic pressure.
In a nephrotoxicity testing application, the generated kidney models are treated with a nephrotoxic substance (Cisplatin), and chemical and optical readouts are applied to quantify the treatment effects. This allows a direct comparison between the different 3D models and a standard 2D cell culture. In the extensive characterizations, the 3D models show advantages over 2D models of the same cell type and the great potential of the presented self-assembly concept for future manufacturing processes in the field of organ modeling and organ-on-a-chip applications. Compared to the state-of-the-art, the fabrication concept reduces the technological requirements, thereby allowing parallelization, an essential step towards the transfer to future (industrial) applications

Angaben zum Objekt

• Standort: Deutsche Nationalbibliothek Frankfurt am Main
• Umfang: Online-Ressource
• Sprache: Englisch
• Anmerkungen: Universität Freiburg, Dissertation, 2021

Klassifikation und Themen

• Schlagwort: Kidney tubules ; Tissue engineering ; BioMEMS ; 3 D bioprinting ; Nephron ; Tissue Engineering ; Selbstorganisation ; Epithel ; Endothel ; In-vitro-Kultur ; Zellkultur ; Mikrosystemtechnik ; Bio-MEMS

Beteiligte, Orts- und Zeitangaben

• Ereignis: Veröffentlichung
• (wo): Freiburg
• (wer): Universität
• (wann): 2021
• Urheber: Tröndle, Kevin
• Beteiligte Personen und Organisationen: Zengerle, Roland ; Albert-Ludwigs-Universität Freiburg. Professur für Anwendungsentwicklung ; Albert-Ludwigs-Universität Freiburg. Fakultät für Angewandte Wissenschaften

Weitere Informationen

• DOI: 10.6094/UNIFR/222717
• URN: urn:nbn:de:bsz:25-freidok-2227171
• Rechteinformation: Kein Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Letzte Aktualisierung: 25.03.2025, 13:52 MEZ