Nanostructures Research Laboratory, Japan Fine Ceramics Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya 456-8587, Japan.
Division of Microbiology and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, 2-5274, Gakkocho-dori, Chuo-ku, Niigata 951-8514, Japan.
Microscopy (Oxf). 2022 Jun 6;71(3):175-180. doi: 10.1093/jmicro/dfac010.
Electron microscopy of biological materials such as bacteria allows multifaceted analysis to understand their structure and function with high resolution, which is difficult to achieve with optical microscopy. However, the samples are damaged or broken by electron beam irradiation and by the vacuum environment. Here, we observed bacteria in a suspension encapsulated in a graphene sandwich that prevents electron beam damage without the need for fixation. Specifically, we demonstrated in situ scanning electron microscopy observation of Escherichia coli in a graphene sandwich containing a perforated membrane as a spacer, encapsulating non-immobilized E. coli between the graphene layers. However, E. coli activity, such as division, was not observed, although the irradiated cells grew slightly when resuspended under optimal culture conditions. Our findings suggest that the graphene sandwich methodology enables the observation of wet E. coli cells by electron microscopy but requires refinement to allow the live imaging of biological materials.
生物材料（如细菌）的电子显微镜观察可以进行多方面的分析，以高分辨率了解其结构和功能，这是光学显微镜难以实现的。然而，电子束辐照和真空环境会破坏或破坏样本。在这里，我们观察了悬浮在石墨烯夹层中的细菌，该夹层可以防止电子束损伤，而无需固定。具体来说，我们在含有穿孔膜作为间隔物的石墨烯夹层中观察到了大肠杆菌的原位扫描电子显微镜观察，将非固定的大肠杆菌封装在石墨烯层之间。然而，尽管在最佳培养条件下重新悬浮时，被辐照的细胞略有生长，但未观察到大肠杆菌的分裂等活性。我们的研究结果表明，石墨烯夹层方法可以通过电子显微镜观察湿的大肠杆菌细胞，但需要进一步改进以实现生物材料的活细胞成像。
