title: 3D Bioprinting of complex channels-Effects of material, orientation, geometry, and cell embedding.
abstract: Creating filled or hollow channels within 3D tissues has become increasingly important in tissue engineering. Channels can serve as vasculature enhancing medium perfusion or as conduits for nerve regeneration. The 3D biofabrication seems to be a promising method to generate these structures within 3D constructs layer-by-layer. In this study, geometry and interface of bioprinted channels were investigated with micro-computed tomography and fluorescent imaging. In filament printing, size and shape of printed channels are influenced by their orientation, which was analyzed by printing horizontally and vertically aligned channels, and by the ink, which was evaluated by comparing channels printed with an alginate-gelatin hydrogel or with an emulsion. The influence of geometry and cell-embedding in the hydrogel on feature size and shape was investigated by printing more complex channels. The generation of hollow channels, induced through leaching of a support phase, was monitored over time. Horizontally aligned channels provided 16× smaller cross-sectional areas than channels in vertical orientation. The smallest feature size of hydrogel filaments was twice as large compared to emulsion filaments. Feature size and shape depended on the geometry but did not alter when living cells were embedded. With that knowledge, channels can be consciously tailored to the particular needs.
authors.affiliation: Department of Health Sciences and Technology, Institute for Biomechanics, ETH Zurich, Zurich, 8093, Switzerland.
authors.forename: Silke
authors.initials: S
authors.lastname: Wüst
authors.affiliation: Department of Health Sciences and Technology, Institute for Biomechanics, ETH Zurich, Zurich, 8093, Switzerland.
authors.forename: Ralph
authors.initials: R
authors.lastname: Müller
authors.affiliation: Department of Health Sciences and Technology, Institute for Biomechanics, ETH Zurich, Zurich, 8093, Switzerland.|Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, Eindhoven, MB, 5600, The Netherlands.|Department of Biomedical Engineering, Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, Eindhoven, MB, 5600, The Netherlands.
authors.forename: Sandra
authors.initials: S
authors.lastname: Hofmann
mesh_terms: D001672:Biocompatible Materials; D066330:Printing, Three-Dimensional; D055114:X-Ray Microtomography
chemical_list: D001672:Biocompatible Materials
keywords: cell-embedding; complex channels; filament-based 3D bioprinting; hydrogel; structure orientation