Professor Do Young Noh's research achieves the first visualization of a mammalian mitochondrion by using coherent x-ray diffractive imaging

□ By using coherent x-ray diffractive imaging, Korean researchers have succeeded in obtaining three-dimensional (3D) internal structures of a mammalian mitochondrion, which was achieved though tomographic imaging at a resolution of approximately 60 nm without the need for sectioning or staining the mitochondrion. The research group included GIST Professor Do Young Noh of the Department of Physics and Photon Science, GIST Professor Giyoong Tae of the Department of Physics and Photon Science, and POSTECH Professor Changyong Song of the Department of Physics.

∘ Mitochondria: Subcellular organelles of eukaryotes involved in energy production.

□ The applied coherent x-ray diffractive imaging technique utilized high-intensity x-rays generated from synchrotron radiation. The approach undertaken by the researchers can resolve the 3D structure of intercellular material or proteins at the nanometer level.

∘ Coherent X-ray Diffractive Imaging: The diffraction pattern of a specimen is first measured and is then directly reconstructed through a mathematical algorithm to obtain a high-resolution image

∘ The researchers accurately measured two-dimensional x-ray diffraction patterns of a single mitochondria and then applied a mathematical algorithm to obtain high-resolution two-dimensional images. Furthermore, three-dimensional images with a resolution of 60 nm were reconstructed by applying the tomography principle of x-ray CT imaging to 2D images obtained from various angles while rotating the mitochondria.

∘ The 3D images obtained in this study were stored in digital form, and it is possible to visualize 2D sectional images from any desired angles and positions.

∘ In addition to the 60 nm resolution 3D images, the researchers presented a method for creating a 2D image with a resolution of 20 nm or less, and they reported the results.

□ Professor Do Young Noh directed the study and commented, "This study has a significance in implementing a technique to obtain three-dimensional images of mitochondria with resolutions of several tens of nanometers, and then, through continuous research to improve the resolution, we plan to acquire higher-resolution images that will provide important clues to our understanding of mitochondria."

□ In addition, applying  this x-ray diffraction imaging technique to the fourth generation synchrotron radiation source (PAL-XFEL), which was completed last year in Korea, is expected to enable researchers to solve many more mysteries of life sciences.

□ This research was carried out at the Center for Advanced X-ray Science (SRC), which is directed by Professor Do Young Noh, and the research was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIP) through SRC. Their paper entitled "Visualization of a Mammalian Mitochondrion by Coherent X-ray Diffractive Imaging" was authored by Yoonhee Kim, Chan Kim, Ou Young Kwon, Daewoong Nam, Sang Soo Kim, Jae Hyun Park, Sunam Kim, Marcus Gallagher-Jones, Yoshiki Kohmura, Tetsuya Ishikawa, Changyong Song, Giyoong Tae, and Do Young Noh, and it was published by Scientific Reports on May 12, 2017.

∘ The first author of this paper Dr. Yoon-Hee Kim will work as a postdoctoral trainee at EuroXFEL, the European Community's 4th generation synchrotron radiation facility.