(161j) 3D Chaotic Printing: Using Simple Chaotic Flows to Fabricate Complex Microstructure

Chaos has the ability to create complex and predictable structures. We demonstrate the use of simple chaotic flows for the fabrication of complex 3D microstructures in cross-linkable or curable liquids, using a process that we refer to as 3D chaotic printing. We inject a drop of â??inkâ? (i.e., a drop of a miscible liquid, fluorescent beads, or cells) into a viscous Newtonian liquid and then apply a chaotic mixing recipe. This generates a complex structure in just a few flow applications. This structure is then preserved with high fidelity and reproducibility by rapid crosslinking or curing of the material. The 3D structure is the result of the rapid alignment of the injected material to the flow manifold. Therefore, its main features are reproducible and the overall process of fabrication is quite robust. Moreover, since the process is deterministic, it is amenable to computational modeling using Computational Fluid Dynamics (CFD).

 In 3D chaotic printing, the interface between the injected material and the fluid matrix grows exponentially with time, and the volume of the injection is finite. Consequently, the average thickness of the lamellae of the material rapidly decreases from a scale of millimeters (the diameter of the injected drop) to one of nanometers. This exponentially fast increase in the interface, as well as the accompanying rapid decrease in the relevant length scales of the microstructure (which still preserves high resolution), is not currently achievable by any other 3D printing technique. We illustrate potential applications for this technology, including the rational reinforcement of constructs by the chaotic alignment of cells and nanoparticles, the fabrication of cell-laden fibers, the development of highly complex multi-lamellar and multi-cellular tissue-like structures for biomedical applications, and the fabrication of bioinspired catalytic surfaces.