The
editorial piece of the issue by Srinivasarao, Iannachione and Parikh provide an interesting perspective on how concepts of non-equilibrium processes are influencing materials science, and how this is particularly true for biological materials. From the abstract of their editorial piece: “Traditional approaches to materials synthesis have largely relied on uniform, equilibrated phases leading to static “condensed-matter” structures (e.g., monolithic single crystals). Departures from these modes of materials design are pervasive in biology. From the folding of proteins to the reorganization of self-regulating cytoskeletal networks, biological materials reflect a major shift in emphasis from equilibrium thermodynamic regimes to out-of-equilibrium regimes. Here, equilibrium structures, determined by global free-energy minima, are replaced by highly structured dynamical states that are out of equilibrium, calling into question the utility of global thermodynamic energy minimization as a first-principles approach. …”
It’s reiterating the question to what extent nature’s bicontinuous geometries (disordered or ordered) can be understood as resulting from similar mechanisms to their synthetic counterparts. An important question… and one that’s going to keep science busy for a while I suspect. We certainly don’t give a comprehensive answer, but I think we’ve got a nice little story to tell about the mechanisms at play in one particular butterfly, and what we c
an learn from the final product (the solid nanostructure) about its formation mechanism. This does not answer the question of how or why nature forms bicontinuous forms, but it provides an extra little piece of the puzzle. (See also our original research article “
Butterfly gyroid nanostructures as a time-frozen glimpse of intracellular membrane development“).
Why would you bother inferring the mechanism from the final product, rather than just observe it by microscopy as it happens? Sure, “You can observe a lot by just watching”, as Yogi Berra famously declared. But with living developing nanostructures, “just watching” is still a challenge.
For sake of completeness, here’s the abstract of our article: Nature’s optical nanomaterials are poised to form the platform for future optical devices with unprecedented functionality. The brilliant colors of many animals arise from the physical interaction of light with nanostructured, multifunctional materials. While their length scale is typically in the 100-nm range, the morphology of these structures can vary strongly. These biological nanostructures are obtained in a controlled manner, using biomaterials under ambient conditions. The formation processes nature employs use elements of both equilibrium self-assembly and far-from-equilibrium and growth processes. This renders not only the colors themselves, but also the formation processes technologically and ecologically highly relevant. Yet, for many biological nanostructured materials, little is known about the formation mechanisms—partially due to a lack of in vivo imaging methods. Here, we present the toolbox of natural multifunctional nanostructures and the current knowledge about the understanding of their far-from-equilibrium assembly processes.
