Automated critical point dry instrumentation for scanning electron microscopy applications

用于扫描电子显微镜应用的自动化临界点干式仪器

• 批准号: RTI-2017-00424
• 负责人: Costea, Mihai
• 金额: $ 3.82万
• 依托单位: Wilfrid Laurier University
• 依托单位国家: 加拿大
• 项目类别: Research Tools and Instruments
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=616673
• 关键词: Automated; critical; point; dry; instrumentation

Scanning electron microscopy (SEM) is currently the standard imaging technique used to generate surface morphological data. The high resolution provided by SEM reveals nano-scale features that are inaccessible to conventional microscopy, while its superior range of focus also allows examination at low magnifications with better results than stereomicroscopy. In classical SEM, the observation takes place in vacuum conditions. This requires the prior removal of water from samples, which is typical for biological specimens. However, direct air dehydration produces cell/tissue deformations that render the samples unsuitable for observation. To circumvent this problem, samples must be either chemically dried or dehydrated using a critical point dry (CPD) instrument. In the former case, the water in cells is substituted with a chemical solvent, which is subsequently evaporated. In the latter case, a CPD instrument replaces the internal water with liquid carbon dioxide (LCO2) at a certain combination of temperature and pressure. The chemical drying process is slow and toxic, and can create artifacts at higher magnifications. Using a CPD instrument is much faster, more accurate, and environmentally friendly. Funds are requested to purchase an automated, programmable CPD Tousimis Autosamdri 931, which will primarily benefit my NSERC Discovery research program on the diversity and evolution of parasitic plants. Overall, this research program is part of the ongoing global effort to catalog life on Earth and understand its natural history and evolution. Its main objective is to reconstruct the evolutionary relationships among the parasitic Cuscuta (dodder) species and revise their taxonomy using morphological, molecular, and cytological data. From a practical point of view, this research program facilitates better identification and management of pest and native Cuscuta species in Canada and worldwide. The CPD instrument will significantly increase research productivity and allow my program to reach its full potential both in terms of efficiency and reduced labor cost/time. The CPD instrument will also support the SEM research of other faculty members at Laurier because no such instrument exists in the university.

扫描电子显微镜（SEM）是目前用于生成表面形态数据的标准成像技术。扫描电镜提供的高分辨率揭示了传统显微镜无法获得的纳米级特征，同时其优越的聚焦范围也允许在低倍率下进行检查，结果比立体显微镜更好。在经典的扫描电镜中，观察是在真空条件下进行的。这需要事先从样品中除去水，这是典型的生物标本。然而，直接空气脱水会产生细胞/组织变形，使样品不适合观察。为了避免这个问题，必须使用临界点干燥（CPD）仪器对样品进行化学干燥或脱水。在前一种情况下，细胞中的水被化学溶剂取代，随后蒸发。在后一种情况下，CPD仪器在一定的温度和压力组合下用液态二氧化碳（LCO2）代替内部水。化学干燥过程缓慢且有毒，并且可以在更高的放大倍数下产生伪影。使用CPD仪器更快、更准确、更环保。