Automated critical point dry instrumentation for scanning electron microscopy applications

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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.