Automated critical point dry instrumentation for scanning electron microscopy applications

扫描电子显微镜(SEM)是目前用于产生表面形态数据的标准成像技术。扫描电子显微镜提供的高分辨率显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还允许在低放大倍数下进行检查，结果比立体显微镜更好。在经典的扫描电子显微镜中，观察是在真空条件下进行的。这需要事先从样品中去除水分，这是生物样品的典型做法。然而，直接空气脱水会产生细胞/组织变形，使样本不适合观察。为了避免这个问题，样品必须进行化学干燥或使用临界点干燥(CPD)仪器进行脱水。在前一种情况下，电池中的水被一种化学溶剂取代，然后被蒸发。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)取代内部水。化学干燥过程缓慢且有毒，可能会在更高的放大倍数下产生文物。使用CPD仪器更快、更准确、更环保。 需要资金购买一台自动、可编程的CPD Tousimis Autosamdri 931，这将主要有利于我的NSERC发现项目，研究寄生植物的多样性和进化。总体而言，这项研究计划是正在进行的全球努力的一部分，目的是对地球上的生命进行分类，并了解其自然历史和进化。它的主要目的是利用形态、分子和细胞学数据重建寄生葫芦科物种之间的进化关系，并修改它们的分类学。从实践的角度来看，这项研究计划有助于更好地识别和管理加拿大和世界各地的害虫和本土葫芦科物种。CPD工具将显著提高研究生产率，并允许我的项目在效率和降低劳动力成本/时间方面充分发挥其潜力。CPD仪器还将支持劳里埃大学其他教职员工的扫描电子显微镜研究，因为该大学没有这样的仪器。

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.