The "scanning electron microscope" (SEM) has been a basic research tool for fifty years, and for those fifty years, scientists have been looking for better ways to observe biological samples under its beam. The problem is that the viewing chamber of the SEM must contain a vacuum (in which liquid water in tissues "boils" away). To overcome this difficulty, scientists have had to resort to all sorts of complicated procedures, including coating the specimens with an ultra-fine layer of gold, quick-freezing samples in special deep-freezes, or treating them with drying solvents.
Now, scientists at the Weizmann Institute of Science have found a way to view samples of biological materials in their natural, "wet" state. Their secret lies in the production of a very thin but tough polymer capsule to enclose the sample, allowing it to withstand the force of the vacuum. Says Dr. Ory Zik, who worked on the capsule with Professor Elisha Moses of the Physics of Complex Systems Department: "The material for the capsule is a result of advances in the area of semiconductors. We came across it while researching ways to apply automation techniques used in the semiconductor industry to the life sciences scanning electron microscopes."
The capsules polymer is unique in that it is allows the electrons with which a SEM works to pass through unobstructed, giving scientists a clear view of what lies within, without the use of tricky, tissue-distorting procedures. Researchers hope the new method will advance the studies of biological materials, such as the lipids that make up fat, which are easily destroyed by the old sample preparation methods.
Alex Smith | EurekAlert!
New biomaterial could replace plastic laminates, greatly reduce pollution
21.09.2017 | Penn State
Stopping problem ice -- by cracking it
21.09.2017 | Norwegian University of Science and Technology
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
22.09.2017 | Life Sciences
22.09.2017 | Medical Engineering
22.09.2017 | Physics and Astronomy