Quantitative characterization of 3D bioprinted structural elements under cell generated forces

• Published in: Nature communications 2019-07, Vol.10 (1), p.3029-9, Article 3029
• Main Authors: Morley, Cameron D., Ellison, S. Tori, Bhattacharjee, Tapomoy, O’Bryan, Christopher S., Zhang, Yifan, Smith, Kourtney F., Kabb, Christopher P., Sebastian, Mathew, Moore, Ginger L., Schulze, Kyle D., Niemi, Sean, Sawyer, W. Gregory, Tran, David D., Mitchell, Duane A., Sumerlin, Brent S., Flores, Catherine T., Angelini, Thomas E.
• Format: Article
• Language: English
• Subjects: 13/106; 13/107; 14/19; 14/34; 3-D printers; 631/57; 639/166/985; 639/301/54/2295; Acrylic Resins - chemistry; Animals; Behavior; Biocompatible Materials; Bioengineering; Bioprinting - methods; Brain cancer; Cell culture; Cell Culture Techniques - methods; Cell Line, Tumor; Cells (biology); Collagen; Construction; Contraction; Deformation mechanisms; Equilibrium; Extracellular Matrix; Gels - chemistry; Humanities and Social Sciences; Materials Testing; Mechanical properties; Mechanics; Methacrylates - chemistry; Mice; Microbeams; Microgels; multidisciplinary; Neurosurgery; NIH 3T3 Cells; Printing, Three-Dimensional; Science; Science (multidisciplinary); Static stability; Structural analysis; Structural failure; Structural members; Three dimensional printing; Tissue engineering; Tissue Engineering - methods
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-019-10919-1

With improving biofabrication technology, 3D bioprinted constructs increasingly resemble real tissues. However, the fundamental principles describing how cell-generated forces within these constructs drive deformations, mechanical instabilities, and structural failures have not been established, even for basic biofabricated building blocks. Here we investigate mechanical behaviours of 3D printed microbeams made from living cells and extracellular matrix, bioprinting these simple structural elements into a 3D culture medium made from packed microgels, creating a mechanically controlled environment that allows the beams to evolve under cell-generated forces. By varying the properties of the beams and the surrounding microgel medium, we explore the mechanical behaviours exhibited by these structures. We observe buckling, axial contraction, failure, and total static stability, and we develop mechanical models of cell-ECM microbeam mechanics. We envision these models and their generalizations to other fundamental 3D shapes to facilitate the predictable design of biofabricated structures using simple building blocks in the future. Advances in biofabrication technology enable 3D printed constructs to resemble real tissues, but it remains unclear how cell-generated forces deform these constructs. Here the authors investigate mechanical behaviours of 3D printed “microbeams” made from mixtures of living cells and extracellular matrix.