Observations of Wood Cell Walls with a Scanning Probe Microscope
Observations of Wood Cell Walls with a Scanning Probe Microscope
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DOI：
10.4236/msa.2016.710052
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发表时间：
2016-09
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影响因子：
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通讯作者：
Manami Yamashita;Masato Yoshida;M. Matsuo;Saori Sato;Hiroyuki Yamamoto
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作者：
Manami Yamashita;Masato Yoshida;M. Matsuo;Saori Sato;Hiroyuki Yamamoto
扫描探针显微镜(SPM)通过检测悬臂和表面之间材料的物理量，用探针观察样品表面。SPM具有高分辨率，可以测量机械特性，如硬度、吸附性能和粘弹性。这些特征使得识别复杂材料的表面结构变得容易；因此，近年来SPM的使用有所增加。木材细胞壁主要由纤维素、半纤维素和木质素组成。据认为，半纤维素和木质素包围着纤维素的骨架，然而，它们的详细形成尚不清楚。因此，我们通过扫描探针显微镜观察木材细胞壁，试图揭示纤维素骨架的形成。根据表面形貌确定了纤维素微原纤束与半纤维素木质素模块复合材料的尺寸为18.48 nm，通过相图确定了纤维素微原纤束的尺寸为15.33 nm。在粘弹性图像中，我们发现同一细胞的每个细胞壁的粘弹性是不同的。这是因为每个细胞壁中的纤维素微纤维向不同的方向倾斜。纤维微原纤维的倾斜度与悬臂的夹角影响粘弹性的测量。
Scanning Probe Microscopes (SPMs) observe specimen surfaces with probes by detecting the physical amount of a material between the cantilever and the surface. SPMs have a high resolution and can measure mechanical characteristics such as stiffness, adsorptive properties, and viscoelasticity. These features make it easy to identify the surface structure of complex materials; therefore, the use of SPMs has increased in recent years. Wood cell walls are primarily composed of cellulose, hemicellulose, and lignin. It is believed that hemicellulose and lignin surround the cellulose framework; however, their detailed formation remains unknown. Therefore, we observed wood cell walls via scanning probe microscopy to try to reveal the formation of the cellulose framework. We determined that the size of the cellulose microfibril bundle and hemicellulose lignin module composite was 18.48 nm based on topography and that the size of the cellulose microfibril bundle was 15.33 nm based on phase images. In the viscoelasticity image, we found that the viscoelasticities of each cell wall of the same cell were not the same. This is because the cellulose microfibrils in each cell wall lean in different directions. The angle between the leaning of the cellulose microfibril and the cantilever affects the viscoelasticity measurement.