Marlene Ihle (Dresden, DE), Max von Witzleben (Dresden, DE), Dr. Sarah Duin (Dresden, DE), Akvile Gasiunaite (Dresden, DE), Professor Michael Gelinsky (Dresden, DE), Dr. Tilman Ahlfeld (Dresden, DE), Dr. Anja Lode (Dresden, DE)
Abstract text (incl. figure legends and references)
Introduction
The requirements for artificial blood vessels are manifold: they have to be dense and mechanically stable tubular structures, they have to allow the formation of an endothelial cell monolayer on the inside and - importantly for surgical applications – they must be suturable. The objective of this work was to develop a fabrication process for integration of polycaprolactone (PCL) meshes into a 4D printing process of an alginate/methylcellulose-based hydrogel by combining melt electrowriting (MEW) and 3D plotting and to characterize the composite structures.
Materials & methods
MEW of PCL (Purasorb PC12 Corbion) meshes was performed with a GeSiM BioScaffolder 3.1 combined with a MEW head as described previously [1]. A blend of 3% alginate and 9% methylcellulose was used for 3D plotting with the BioScaffolder (first layer without gap between the parallel strands; second and third layer on top of each other with varying distances between the parallel strands). After air-drying, shape-morphing into tubes was induced by immersion into CaCl2-solution followed by freeze drying. The samples were characterized by tensile test, sewing and perfusion test, microscopic analyses and cell seeding experiments with human fibroblasts and endothelial cells.
Results
Tubular structures with diameters of 2-5 mm were generated; the PCL meshes could be integrated without inhibiting the shape morphing effect. The composite structures containing PCL meshes exhibited a higher tensile strength compared to the pure hydrogel structures. Moreover, the integration of PCL meshes resulted in tubes which are sewable and could be perfused without leakage. Finally, the composite structures were successfully seeded with cells.
Conclusion
The feasibility of this multi-step fabrication process of a self-assembling fibre-hydrogel composite tubular structure was demonstrated which is potentially applicable for blood vessel tissue engineering.
[1] von Witzleben et al. 2021, doi.org/10.1002/adhm.202002089