Toword the development of "light microscope" induced by electron excitation

2018 Fiscal Year Final Research Report

• Project/Area Number: 17K19516
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Research Field: Biomedical structure and function and related fields
• Research Institution: Tokyo University of Agriculture and Technology
• Principal Investigator: Minoda Hiroki 東京農工大学, 工学(系)研究科(研究院), 教授 (20240757)
• Project Period (FY): 2017-06-30 – 2019-03-31
• Keywords: eGFP / カソードルミネセンス / 電子線誘起光学顕微鏡 / 光学顕微鏡

Outline of Final Research Achievements

In this research project, the possibility to develop low energy electron illumination induced light microscopy was examined. It is well known that Green fluorescent protein is widely used in the life science. We found that the enhanced GFP (eGFP) can emit cathodoluminescence (CL) by electron irradiation. Wavelength of the electron wave is much shorter than that of the light wave and it would permit the possibility to develop a “light microscope”induced by electron irradiation. This should have higher spatial resolution than conventional light microscopes. To realize high resolution “light microscope” using light emission from eGFP CL, we investigate electron damage of the eGFP. The proteins are considered to be electron sensitive, but eGFP is more than ten times stronger for electron irradiation than Rubrene which is considered to have high resistance against the electron irradiation. We also found that the electron resistance of the eGFP depends on the neighboring environment.

Free Research Field

ナノサイエンス

Academic Significance and Societal Importance of the Research Achievements

一般に、タンパク質は電子線損傷しやすく、電子の照射により容易に破壊されやすいと考えられているが、本実験でテスト試料として用いたeGFPが、分子の中では電子線による破壊に比較的強いとされているルブレンに比べて1桁以上壊れにくいという結果が得られた。また、破壊のし易さは、試料周りの環境によって大きく依存することも分かった。以上のことから、本研究により電子線誘起の光学顕微鏡開発の可能性がさらに高まったと言える。この装置の実現は、従来より格段に高い空間分解能での生命現象観察・研究の道を拓く意味で、今後のこの分野の発展を大きく前進させたと言える。