Imaging the contours of living cells with a new graphene nanoimaging technique

PICTURE

PICTURE: Professor Dae Won Moon (sitting) and others. Heejin Lim (standing) in his laboratory at DGIST, Korea. view more

Credit: DGIST

With each passing day, human technology is becoming more sophisticated, and we are becoming better equipped to study biological processes and molecular and cellular structures more deeply, gaining a growing understanding of the underlying mechanisms of diseases such as cancer, Alzheimer’s and others.

Today, nanoimaging, one of such state-of-the-art technologies, is widely used for the structural characterization of subcellular components and cellular molecules such as cholesterol and fatty acids. But it’s not without its limitations, as Professor Dae Won Moon of Daegu Gyeongbuk Institute of Technology (DGIST), Korea, a leading scientist in a recent groundbreaking study advancing the field, explains, “The most advanced nanoimaging techniques use accelerated electron or ion beams in ultra-high environments. In order for cells to be introduced into such an environment, we must chemically repair them and physically freeze or dry them. But such processes impair the original molecular composition and distribution of the cells. ”

Professor Moon and his team wanted to find a way to avoid this deterioration. “We wanted to apply advanced nanoimaging techniques in ultra-high vacuum environments to living cells in solution without any chemical or physical treatment, not even fluorescent staining, to obtain essential biomolecular information that is impossible to obtain using conventional bioimaging techniques,” Dr. Explains Heejin Lim, a key member of the research team. Their new solution was published in Natural methods.

Their technique involves placing wet cells on a moist substrate coated with collagen with micro holes, which in turn is on top of the cell culture medium reservoir. The cells were then covered with a single layer of graphene. Graphene is expected to protect cells from drying out and cell membranes from decay.

By optical microscopy, the scientists confirmed that, when prepared in this way, the cells remain viable and alive even ten minutes after being placed in an ultra-high vacuum environment. The scientists also performed nanoimaging, especially secondary ionic fat spectrometric imaging, in this environment for up to 30 minutes. The images they took in the first ten minutes give a highly detailed (submicrometer) picture of the actual essential distribution of lipids in their original states in the cell membranes; for this duration the membranes did not suffer significant distortions.

However, even with this method, the ion beam collision cascade at a point on the graphene film can create a hole large enough that some lipid particles can escape. But although this degradation occurs on the cell membrane, it is not significant within the ten-minute window and there is no solution leakage. Further, graphene molecules react with water molecules to repair themselves. So, all in all, this is a great way to learn about cell membrane molecules in their original state in high resolution.

“I assume that our innovative technique can be widely used in many biomedical imaging laboratories for more reliable cell bioanalysis and ultimately for overcoming complex diseases,” says Prof. Moon.

Will this innovation become the norm? Only time will tell!

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Reference

Authors: Heejin Lim¬1, Sun Young Lee1, Yereum Park2, Hyeonggyu Jin3, Daeha Seo3, Yun Hee Jang2 and Dae Won Moon1,4

Title of the original paper: Recording of mass spectrometry of untreated wet cell membranes in solution using single-layer graphene

Magazine: Natural methods

DOI: https: //doi.org /10.1038 /s41592-020-01055-6

Associations: 1Department of New Biology, DGIST, Daegu, Republic of Korea

2 Department of Energy Science and Engineering, DGIST, Daegu, Republic of Korea

3D Department of New Materials Science, DGIST, Daegu, Republic of Korea

4School of Undergraduate Studies, DGIST, Daegu, Republic of Korea

* Author’s e-mail address: [email protected]

About the Daegu Gyeongbuk Institute of Science and Technology (DGIST)

The Daegu Gyeongbuk Institute of Science and Technology (DGIST) is a well-known and respected research institute located in Daegu, Republic of Korea. Founded in 2004 by the Korean government, the main goal of DGIST is to promote national science and technology, as well as strengthen the local economy.

With the vision of “Changing the World through Convergence”, DGIST has undertaken a wide range of research in various fields of science and technology. DGIST has adopted a multidisciplinary approach to research and undertaken intensive studies in some of today’s most important areas. DGIST also has state-of-the-art infrastructure that enables cutting-edge research in materials science, robotics, cognitive sciences, and communication engineering.

Website: https: //www.dgist.ac.kr /en /html /sub01 /010204.html

About the authors

Dr. Dae Won Moon is a professor in the Department of New Biology and is a member of the NanoBio Imaging Laboratory at DGIST. He began his career with a doctorate in chemistry from Pennsylvania State University, USA, in 1984, and is now the editor of the journal Critical Reviews in Solid State and Materials Science. His research interests include coherent Raman scattering, surface plasmon resonance ellipsometry, mass spectrometry, and in-flight scattering of medium-energy ions. He has won several awards in Korea for his outstanding contributions in this field, including over 180 publications.

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