Electron microscopes already provide amazingly clear images of samples just a few nanometers across. But if you want a good look at living tissue, look again.
In this image generated by an electron microscope, the white dots are the protein ferritin. The dark circle in the middle is a bubble trapped within the graphene capsule enclosing the sample, proving the existence of a liquid.
“You can’t put liquid in an electron microscope,” says Tolou Shokuhfar, of Michigan Technological University. “So, if you have a hydrated sample—and all living things are hydrated—you have to freeze it, like a blueberry in an ice cube, and cut it into a million thin pieces, so the electrons can pass through. Only then can you image it to see what’s going on.”
After such treatment, the blueberry isn’t what it was, and neither is human tissue. Shokuhfar, an assistant professor of mechanical engineering-engineering mechanics, wondered if there might be a way to make electron microscopes more friendly to biological samples. That way, you might get a much better view of what’s really going on at the sub-cellular level.
So she joined colleagues at the University of Illinois-Chicago (UIC), and together they found a way. “You don’t need to freeze the blueberry, you don’t need to slice it up with a diamond knife,” she said. “You just put it in the electron microscope, and you can get down and see the atoms.”
The trick was to encapsulate the sample so that all the water stayed put while the electrons passed through freely. To do that, the team, including Robert F. Klie, an associate professor of physics and mechanical and industrial engineering at UIC, and UIC graduate student Canhui Wang, turned to graphene.
“Graphene is just a single layer of carbon atoms, and electrons can go through it easily, but water does not,” Klie said. “If you put a drop of water on graphene and top it with graphene, it forms this little balloon of water.” The graphene is strong enough to hold the water inside, even within the vacuum of an electron microscope.
The team tried their technique on a biochemical that plays a major role in human health: ferritin. “It’s a protein that stores and releases iron, which is critical for many body functions, and if ferritin isn’t working right, it may be contributing to lots of diseases, including Alzheimer’s and cancer,” Shokuhfar said.
The team made a microscopic sandwich, with ferritin immersed in water as the filling and graphene as the bread, and sealed the edges. Then, using a scanning transmission electron microscope, they captured a variety of images showing ferritin’s atomic structure. In addition, they used a special type of spectroscopy to identify various atomic and electronic structures within the ferritin. Those images showed that the ferritin was releasing iron and pinpointed its specific form.
If the technique were used to compare ferritin taken from diseased tissue with healthy ferritin, it could provide new insights into illness at the molecular level. Those discoveries could lead to new treatments. “I believe this will allow us to identify disease signatures in ferritin and many other proteins,” Shokuhfar said.
An article on their work, “High-Resolution Electron Microscopy and Spectroscopy of Ferritin in Biocompatible Graphene Liquid Cells and Graphene Sandwiches,” ( http://onlinelibrary.wiley.com/doi/10.1002/adma.201306069/abstract )was published Feb. 4 in Advanced Materials. Qiao Qiao, formerly a graduate student in Klie's UIC lab and now a postdoctoral fellow at Vanderbilt University, is also a coauthor on the study.
The work was funded by Michigan Technological University with additional support from a National Science Foundation grant to UIC, number DMR-0959470. The research was conducted at the University of Illinois-Chicago.Tolou Shokuhfar, cell 906-370-7657, firstname.lastname@example.org
Marcia Goodrich | Newswise
Tag it EASI – a new method for accurate protein analysis
20.06.2018 | Max-Planck-Institut für Biochemie
How to track and trace a protein: Nanosensors monitor intracellular deliveries
19.06.2018 | Universität Basel
In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.
Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...
Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...
Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.
Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...
The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.
Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.
An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.
Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...
13.06.2018 | Event News
08.06.2018 | Event News
05.06.2018 | Event News
20.06.2018 | Materials Sciences
20.06.2018 | Materials Sciences
20.06.2018 | Materials Sciences