Lignin-free wood has been successfully developed via a two-step chemical treatment while maintaining its inherent hierarchical structure. The first step was alcoholysis which was conducted using ethylene glycol, and whose condition was optimized by monitoring the removal of lignin using infrared spectroscopy. The second step was bleaching wherein the delignification proceeded from the surface to the core of the wood block, and finally resulted in complete decolorization. Although the wood block was free from lignin and hemicellulose as approximately confirmed by the chemical composition analysis, the 3-dimensional colorless wood block was almost unaltered, even after freeze–drying. Then, multidirectional observation was performed to investigate whether the natural hierarchical structure from anatomical- to nano-level was maintained. Optical microscopy, X-ray microcomputed tomography, X-ray diffractometry, and transmission electron microscopy demonstrated that all the stages of hierarchical structure were maintained. The lignin-free wood block has great potential for novel materials that are supported by a 3-dimensional wooden architecture. The derived lignin-free wood is also a suitable specimen that can be used to understand the formation and functionality of the anatomical structure and lignified cell wall.

中文翻译：

---

通过两步脱木素作用（包括醇解和漂白）并保持自然层次结构，开发无色木材

不含木质素的木材通过两步化学处理成功开发出来，同时保持了其固有的层次结构。第一步是醇解，其使用乙二醇进行，其条件通过使用红外光谱法监测木质素的去除来优化。第二步是漂白，其中脱木素作用是从木块的表面到核心，最后导致完全脱色。尽管该木块不含木质素和半纤维素（通过化学成分分析已大致确认），但即使冷冻干燥后，该3维无色木块也几乎没有改变。然后，进行多方向观察以研究是否保持了从解剖学到纳米水平的自然分层结构。光学显微镜，X射线计算机断层扫描，X射线衍射和透射电子显微镜表明，所有层次结构的阶段都得到了维持。不含木质素的木块具有由3维木制建筑支撑的新颖材料的巨大潜力。衍生的不含木质素的木材也是合适的标本，可用于了解解剖结构和木质化细胞壁的形成和功能。