Uncovering the underlying mechanisms guiding the behaviors of natural sticky glue is of important significance for developing novel biomimetic or bioinspired materials to regulate cellular activities. Carnivorous plants secrete adhesive mucilage to capture insects, but the nanoscale organizations of the mucilage are still not fully understood. In particular, the advent of atomic force microscopy (AFM) provides a powerful tool for investigating the structures and properties of biological samples in their native states with unprecedented spatial resolution, offering novel possibilities for the studies of characterizing biomaterials. In this work, AFM was utilized to reveal the nanostructures of mucilage secreted by carnivorous plant (Pinguicula and Sarracenia) for promoting cell growth. AFM imaging of the mucilage-coated substrates in air showed that nanostructures (nanoparticles and nanofibers) with different assembly behaviors were significantly observed in mucilage, which were confirmed by electron microscopy imaging. AFM in situ imaging in liquids remarkably revealed that nanoparticles were contained in native mucilage. The mechanical properties of individual nanofibers were visualized and quantified by AFM indenting assays. The elemental organizations of the mucilage were analyzed, and the experiments of cells grown on mucilage-coated substrates indicated that carnivorous plant mucilage could facilitate cell growth. The research provides novel insights into the nanostructures and mechanical properties as well as biological functions of mucilage secreted by carnivorous plants, which will have potential impacts on the studies of biomaterials for tuning cell behaviors.

中文翻译：

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原子力显微镜下食肉植物粘液的纳米级组织和功能分析

揭示指导天然粘性胶行为的潜在机制对于开发新型仿生或仿生材料以调节细胞活动具有重要意义。食肉植物分泌粘液来捕捉昆虫，但粘液的纳米级组织仍未完全了解。特别是，原子力显微镜 (AFM) 的出现提供了一种强大的工具，可以以前所未有的空间分辨率研究原始状态下生物样品的结构和性质，为表征生物材料的研究提供了新的可能性。在这项工作中，AFM 被用来揭示食肉植物（Pinguicula 和 Sarracenia）分泌的粘液的纳米结构，以促进细胞生长。空气中粘液涂层基材的 AFM 成像表明，在粘液中显着观察到具有不同组装行为的纳米结构（纳米颗粒和纳米纤维），这通过电子显微镜成像得到证实。液体中的 AFM 原位成像显着显示纳米颗粒包含在天然粘液中。单个纳米纤维的机械性能通过 AFM 压痕分析进行可视化和量化。分析了粘液的元素组织，在粘液包被的基质上生长的细胞实验表明，食肉植物粘液可以促进细胞生长。该研究为肉食植物分泌的粘液的纳米结构和机械特性以及生物学功能提供了新的见解，