基于TERS的杨木纤维细胞壁微细纤维精细结构研究

微细纤维是木质纤维细胞壁的骨架，其精细结构直接决定了木质纤维生物质的物理和化学性质。然而，人们对微细纤维的精细结构认知还很不充分，尤其是纤维素-半纤维素-木质素的空间关系、微细纤维结晶-无定形结构的组合方式等问题尚不明确。针对这些问题，本项目基于针尖增强拉曼散射（TERS）技术，以我国人工林重要树种杨树为研究对象，在纳米尺度下原位采集杨木纤维细胞壁微细纤维的分子光谱；采用多元数据分析策略，快速分辨纤维素、半纤维素与木质素纯光谱，获得对应的化学成像（Chemical Imaging）。在此基础上，解析木质素与半纤维素在微细纤维中的嵌入形式，阐明纳米尺度下纤维素-半纤维素-木质素的空间关系；提取纤维素分子光谱中的结晶度信息，确定微细纤维的结晶-无定形结构组合方式，构建微细纤维精细结构模型。本项目研究成果可为杨木等木质纤维生物质高效利用、主要组分定向分离转化等研究提供科学的理论依据。

Microfibers are the skeleton of the lignocellulosic cell walls. Its fine structure determines the physical and chemical properties of lignocellulosic biomass. However, the understanding of the fine structure of microfibrils is still inadequate, especially the spatial relationship between cellulose, hemicelluloses, and lignin, and the combination mode of crystal and amorphous structure. To address these issues, we proposed a strategy based on the Tip-Enhanced Raman Scattering (TERS). TERS is applied to collect the molecular spectra of microfibrils in the cell wall of poplar in situ at the nanometer scale. The multivariate data analysis is employed to quickly distinguish the pure spectrum of cellulose, hemicelluloses and lignin, and obtain the chemical imaging of these components with a high resolution. Then the embedding form of lignin and hemicelluloss in microfibers is analyzed, and the spatial relationship between cellulose hemicelluloses and lignin is clarified for the first time. The crystallinity information is extracted from the cellulose spectrum to illustrate the combination mode of crystal and amorphous structure in microfibers. We aim to construct the fine structure of poplar microfibers . The results will provide scientific theoretical basis for the efficient utilization of lignocellulosic biomass.