Okeyoshi Kosuke, Okajima Maiko K, Kaneko Tatsuo
Japan Advanced Institute of Science and Technology , 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.
Biomacromolecules. 2016 Jun 13;17(6):2096-103. doi: 10.1021/acs.biomac.6b00302. Epub 2016 Apr 29.
A drying environment is always a proposition faced by dynamic living organisms using water, which are driven by biopolymer-based micro- and macrostructures. Here, we introduce a drying process for aqueous liquid crystalline (LC) solutions composed of biopolymer with extremely high molecular weight components such as polysaccharides, cytoskeletal proteins, and DNA. On controlling the mobility of the LC microdomain, the solutions showed milliscale self-integration starting from the unstable gas-LC interface during drying. In particular, we first identified giant rod-like microdomains (∼1 μm diameter and more than 20 μm length) of the mega-molecular polysaccharide, sacran, which is remarkably larger than other polysaccharides. These microdomains led to the formation of a single milliscale macrodomain on the interface. In addition, the dried polymer films on a solid substrate also revealed that such integration depends on the size of the microdomain. We envision that this simple drying method will be useful not only for understanding the biopolymer hierarchization at the macroscale level but also for preparation of surfaces with direction controllability, as seen in living organisms, for use in various fields such as diffusion, mechanics, and photonics.
干燥环境始终是基于生物聚合物的微观和宏观结构驱动的、依赖水生存的动态生物体所面临的一个问题。在此，我们介绍了一种由具有极高分子量成分（如多糖、细胞骨架蛋白和DNA）的生物聚合物组成的水性液晶（LC）溶液的干燥过程。在控制LC微区的流动性时，这些溶液在干燥过程中从不稳定的气-LC界面开始呈现毫米级的自整合现象。特别是，我们首次鉴定出了巨型分子多糖——帚叉藻聚糖的巨型棒状微区（直径约1μm，长度超过20μm），其尺寸明显大于其他多糖。这些微区导致在界面上形成单个毫米级的宏观区域。此外，固体基板上的干燥聚合物薄膜还表明，这种整合取决于微区的大小。我们设想，这种简单的干燥方法不仅有助于在宏观尺度上理解生物聚合物的层次结构，还可用于制备具有如生物体中所见的方向可控性的表面，以应用于扩散、力学和光子学等各个领域。
