Assessment of Collagen-Based Inks to Develop Bilayer Constructs by 3D Printing

Multi-material 3D printing is a valuable technique for creating multi-layered constructs that replicate the composition and organization of tissues. With this in mind, bilayer constructs are produced through 3D printing using two inks based on proteins. On the one hand, a gelatin ink with different carboxymethyl cellulose (CMC) contents is prepared and based on the rheological performance, the ink with 3 wt.% CMC is selected for the bottom layer of the construct. On the other hand, collagen-inks are also rheologically characterized, demonstrating shear thinning behavior and self-supporting ability. Based on these results, the collagen ink with riboflavin is selected as the top layer of the construct. The printing conditions, such as tip gauge and extrusion temperatures, are optimized, leading to homogeneous and replicable constructs with the required elastic modulus for their application as dermal substitutes.