Medical Research Institute, Kanazawa Medical University, 1-1 Daigaku, Uchinada-machi, Kahoku-gun 920-0293, Japan.
Microsc Res Tech. 2011 Dec;74(12):1104-8. doi: 10.1002/jemt.21001. Epub 2011 Apr 29.
An ionic liquid (IL) is a salt that remains in the liquid state at room temperature. It does not vaporize under vacuum and imparts electrical conductivity to samples for observation by scanning electron microscopy (SEM). Recently, the usefulness of ILs has been widely recognized. In our previous study, one of the ILs 1-ethyl-3-methylimidazolium tetrafluoroborate (EtMelm(+) BF(4)(-)) was used for SEM analysis of biological samples. In comparison with the conventional method, samples prepared using EtMelm(+) BF(4)(-) provided more detailed SEM images of the cell ultrastructure, enabling the observation of protrusions. In addition, the IL treatment is a less time consuming and simple method that does not include dehydration, drying, and conductivity treatments, which are an essential parts of the conventional method. In this study, we compared the usefulness of four hydrophobic and three hydrophilic ILs for SEM to observe fixed cultured human A549 cells. All ILs worked well to prevent "charge-up" effect for SEM observation. However, the hydrophilic ILs tended to provide clearer images than the hydrophobic ILs. We concluded that various ILs can be used for SEM sample preparation and their application to a wide range of fields is anticipated in future.
离子液体 (IL) 是一种在室温下保持液态的盐。它在真空中不会蒸发，并为扫描电子显微镜 (SEM) 观察的样品提供电导率。最近，离子液体的用途得到了广泛的认可。在我们之前的研究中，我们使用了一种离子液体 1-乙基-3-甲基咪唑四氟硼酸盐 (EtMelm(+) BF(4)(-)) 来进行生物样品的 SEM 分析。与传统方法相比，使用 EtMelm(+) BF(4)(-) 制备的样品提供了更详细的细胞超微结构 SEM 图像，能够观察到突起。此外，离子液体处理是一种耗时更少、更简单的方法，不包括脱水、干燥和导电性处理，这些是传统方法的重要组成部分。在这项研究中，我们比较了四种疏水性和三种亲水性离子液体在 SEM 观察固定培养的人 A549 细胞中的用途。所有离子液体都能很好地防止 SEM 观察中的“电荷积累”效应。然而，亲水性离子液体往往比疏水性离子液体提供更清晰的图像。我们得出结论，各种离子液体可用于 SEM 样品制备，预计它们在未来将应用于更广泛的领域。
