Precision Instrumentation Center, College of Science, National Taiwan University, Taipei 106, Taiwan.
Microsc Res Tech. 2012 Feb;75(2):103-11. doi: 10.1002/jemt.21031. Epub 2011 Jul 14.
A pre-cryogenic holder (cryo-holder) facilitating cryo-specimen observation under a conventional scanning electron microscope (SEM) is described. This cryo-holder includes a specimen-holding unit (the stub) and a cryogenic energy-storing unit (a composite of three cylinders assembled with a screw). After cooling, the cryo-holder can continue supplying cryogenic energy to extend the observation time for the specimen in a conventional SEM. Moreover, the cryogenic energy-storing unit could retain appropriate liquid nitrogen that can evaporate to prevent frost deposition on the surface of the specimen. This device is proved feasible for various tissues and cells, and can be applied to the fields of both biology and material science. We have employed this novel cryo-holder for observation of yeast cells, trichome, and epidermal cells in the leaf of Arabidopsis thaliana, compound eyes of insects, red blood cells, filiform papillae on the surface of rat tongue, agar medium, water molecules, penicillium, etc. All results suggested that the newly designed cryo-holder is applicable for cryo-specimen observation under a conventional SEM without cooling system. Most importantly, the design of this cryo-holder is simple and easy to operate and could adapt a conventional SEM to a plain type cryo-SEM affordable for most laboratories.
一种预低温 holder（cryo-holder），可在常规扫描电子显微镜（SEM）下观察 cryo-specimen，该预低温 holder 包括标本保持单元（stub）和低温储能单元（由三个组装在一起的圆柱体组成的复合物）。冷却后，cryo-holder 可以继续提供低温能量，以延长常规 SEM 下标本的观察时间。此外，低温储能单元可以保留适量的液氮，以防止液氮在标本表面结霜。该装置已被证明适用于各种组织和细胞，可应用于生物学和材料科学领域。我们已经使用这种新型的 cryo-holder 观察了酵母细胞、拟南芥叶表皮细胞、毛状体、昆虫复眼、红细胞、鼠舌表面丝状乳头、琼脂培养基、水分子、青霉菌等。所有结果表明，新设计的 cryo-holder 适用于无冷却系统的常规 SEM 下 cryo-specimen 观察。最重要的是，这种 cryo-holder 的设计简单易用，可以将常规 SEM 改装成适合大多数实验室的普通 cryo-SEM。
