Plug‐and‐Play Multimaterial Chaotic Printing/Bioprinting to Produce Radial and Axial Micropatterns in Hydrogel Filaments

Nature abounds with micro‐architected materials containing layered multi‐material patterns that often transition within the very same monolithic piece. Fabricating these complex materials using current technologies is challenging. Multimaterial chaotic printing is presented—an extrusive printing method based on the use of chaotic advection—that can fabricate microstructured hydrogels with well‐defined multimaterial and multilayered micropatterns. Printheads containing internal Kenics static mixing (KSM) elements and top‐ and lateral‐positioned inlets are used to produce a wide repertoire of multilayered hydrogel filaments. In this plug‐and‐play system, the radial and axial micropatterns can be designed ad hoc by defining the printhead configuration (i.e., the number of KSM elements and inlets, and the inlet positions) and the flow program (i.e., activation/deactivation of the ink‐flow through each inlet). Computational fluid dynamics simulations closely predict the microstructure obtained by a given printhead configuration. The application of this platform is illustrated for easy fabrication of fibers with radial microgradients, bacterial ecosystems, structured emulsions, micro‐channeled hydrogel filaments, a pre‐vascularized tumor niche model, and skeletal muscle‐like tissues with axial and radial transitions of bioactive glass compartments. It is envisioned that multimaterial chaotic printing will be a valuable addition to the toolbox of additive manufacturing for the rational fabrication of advanced materials.