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

A detailed understanding of the molecular structure of the cell membrane is important for learning more about the basic cellular mechanisms of disease. New techniques are needed to observe these miniature structures in high resolution and with great precision. Credit: Nature Methods

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!

The new microscopy analysis enables the detection of the central adhesion complex

More information:
Heejin Lim et al., Mass spectrometry of imaging of untreated wet cell membranes in solution using single-layer graphene, Natural methods (2021). DOI: 10.1038 / s41592-020-01055-6

Provided by DGIST (Daegu Gyeongbuk Institute of Science and Technology)

Citation: Imaging the contours of living cells with a new graphene nanoimaging technique (2021, February 17) retrieved February 17, 2021 from

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