Self-Assembly of Structured Colloidal Gels for High-Resolution 3D Micropatterning of Proteins at Scale.

Self-assembly, the spontaneous ordering of components into patterns, is widespread in nature and fundamental to generating function across length scales. Morphogen gradients in biological development are paradigmatic as both products and effectors of self-assembly and various attempts have been made to reproduce such gradients in biomaterial design. To date, approaches have typically utilized top-down fabrication techniques that, while allowing high-resolution control, are limited by scale and require chemical cross-linking steps to stabilize morphogen patterns in time. Here, a bottom-up approach to protein patterning is developed based on a novel binary reaction-diffusion process where proteins function as diffusive reactants to assemble a nanoclay-protein composite hydrogel. Using this approach, it is possible to generate scalable and highly stable 3D patterns of target proteins down to sub-cellular resolution through only physical interactions between clay nanoparticles and the proteins and ions present in blood. Patterned nanoclay gels are able to guide cell behavior to precisely template bone tissue formation in vivo. These results demonstrate the feasibility of stabilizing 3D gradients of biological signals through self-assembly processes and open up new possibilities for morphogen-based therapeutic strategies and models of biological development and repair.