Polysaccharides are important biomacromolecules existing in all plants, most of which are integrated into a fibrillar structure called the cell wall. In the absence of an effective methodology for polysaccharide analysis that arises from compositional heterogeneity and structural flexibility, our knowledge of cell wall architecture and function is greatly constrained. Here, we develop a single-molecule approach for identifying plant polysaccharides with acetylated modification levels. We designed a solid-state nanopore sensor supported by a free-standing SiN_x membrane in fluidic cells. This device was able to detect cell wall polysaccharide xylans at concentrations as low as 5 ng/μL and discriminate xylans with hyperacetylated and unacetylated modifications. We further demonstrated the capability of this method in distinguishing arabinoxylan and glucuronoxylan in monocot and dicot plants. Combining the data for categorizing polysaccharide mixtures, our study establishes a single-molecule platform for polysaccharide analysis, opening a new avenue for understanding cell wall structures, and expanding polysaccharide applications.

多糖是存在于所有植物中的重要生物大分子，其中大部分整合成称为细胞壁的纤维状结构。由于成分异质性和结构灵活性，缺乏有效的多糖分析方法，我们对细胞壁结构和功能的了解受到很大限制。在这里，我们开发了一种单分子方法来鉴定具有乙酰化修饰水平的植物多糖。我们设计了一种固态纳米孔传感器，由流体单元中的独立式 SiN _x膜支持。该装置能够检测浓度低至 5 ng/μL 的细胞壁多糖木聚糖，并区分具有超乙酰化和非乙酰化修饰的木聚糖。我们进一步证明了该方法区分单子叶植物和双子叶植物中的阿拉伯木聚糖和葡萄糖醛酸木聚糖的能力。结合多糖混合物分类的数据，我们的研究建立了多糖分析的单分子平台，为理解细胞壁结构和扩大多糖应用开辟了新途径。