A new material changes its conductivity depending on the concentration of CO2 in the environment. The researchers who developed it have utilized the material to produce a miniature, simply constructed sensor. Material scientists at ETH Zurich and the Max Planck Institute of Colloids and Int ... more
Advanced imaging for bone research and materials scienceHigh-resolution method for computed nano-tomography developed
A novel nano-tomography method developed by a team of researchers from the Technische Universität München (TUM), the Paul Scherrer Institute (PSI) and the ETH Zurich opens the door to computed tomography examinations of minute structures at nanometer resolutions. The new method makes possible, for example, three-dimensional internal imaging of fragile bone structures. The first nano-CT images generated with this procedure is published in Nature . This new technique will facilitate advances in both life sciences and materials sciences.
Osteoporosis, a medical condition in which bones become brittle and fragile from a loss of density, is among the most common diseases in aging bones: In Germany around a quarter of the population aged over 50 is affected. Patients' bone material shrinks rapidly, leading to a significantly increased risk of fracture. In clinical research to date, osteoporosis is diagnosed almost exclusively by establishing an overall reduction in bone density. This approach, however, gives little information about the associated, and equally important, local structure and bone density changes. Franz Pfeiffer, TUM professor for Biomedical Physics and head of the research team, has resolved the dilemma: “With our newly developed nano-CT method it is now possible to visualize the bone structure and density changes at high resolutions and in 3D. This enables us to do research on structural changes related to osteoporosis on a nanoscale and thus develop better therapeutic approaches.”
During development, Pfeiffer’s team built on X-ray computed tomography (CT). The principle is well established – CT scanners are used every day in hospitals and medical practices for the diagnostic screening of the human body. In the process the human body is X-rayed while a detector records from different angles how much radiation is being absorbed. In principle it is nothing more than taking multiple X-ray pictures from various directions. A number of such pictures are then used to generate digital 3D images of the body's interior using image processing.
The newly developed method measures not only the overall beam intensity absorbed by the object under examination at each angle, but also those parts of the X-ray beam that are deflected in different directions – “diffracted” in the language of physics. Such a diffraction pattern is generated for every point in the sample. This supplies additional information about the exact nanostructure, as X-ray radiation is particularly sensitive to the tiniest of structural changes. “Because we have to take and process so many individual pictures with extreme precision, it was particularly important during the implementation of the method to use high-brilliance X-ray radiation and fast, low-noise pixel detectors – both available at the Swiss Light Source (SLS),” says Oliver Bunk, who was responsible for the requisite experimental setup at the PSI synchrotron facilities in Switzerland.
The diffraction patterns are then processed using an algorithm developed by the team. TUM researcher Martin Dierolf, lead author of the Nature article, explains: “We developed an image reconstruction algorithm that generates a high-resolution, three-dimensional image of the sample using over one hundred thousand diffraction patterns. This algorithm takes into account not only classical X-ray absorption, but also the significantly more sensitive phase shift of the X-rays.” A showcase example of the new technique was the examination of a 25-micrometer, superfine bone specimen of a laboratory mouse – with surprisingly exact results. The so-called phase contrast CT pictures show even smallest variations in the specimen’s bone density with extremely high precision: Cross-sections of cavities where bone cells reside and their roughly 100 nanometer-fine interconnection network are clearly visible.
“Although the new nano-CT procedure does not achieve the spatial resolution currently available in electron microscopy, it can – because of the high penetration of X-rays – generate three-dimensional tomography images of bone samples,” comments Roger Wepf, director of the Electron Microscopy Center of the ETH Zurich (EMEZ). “Furthermore, the new nano-CT procedure stands out with its high precision bone density measurement capacity, which is particularly important in bone research.” This method will open the door to more precise studies on the early phase of osteoporosis, in particular, and evaluation of the therapeutic outcomes of various treatments in clinical studies.
The new technique is also very interesting for non-medical applications: Further fields of application include the development of new materials in materials science or in the characterization of semiconductor components. Ultimately, the nano-CT procedure may also be transferred to novel, laser-based X-ray sources, such as the ones currently under development at the Cluster of Excellence “Munich-Centre for Advanced Photonics” (MAP) and at the recently approved large-scale research project “Centre for Advanced Laser Applications” (CALA) on the TUM-Campus Garching near Munich.
Original publication: Martin Dierolf, Andreas Menzel, Pierre Thibault, Philipp Schneider, Cameron M. Kewish, Roger Wepf, Oliver Bunk, Franz Pfeiffer: “Ptychographic X-Ray Computed Tomography at the Nano-Scale”. Nature, September 23, 2010.
NanoMRI is a scanning technique that produces nondestructive, high-resolution 3-D images of nanoscale objects, and it promises to become a powerful tool for researchers and companies exploring the shape and function of biological materials such as viruses and cells in much the same way as c ... more
In the majority of cases, the onset of cancer is characterised by a minor change in a person's genetic material. A cell's DNA mutates in a particular area to the extent that the cell no longer divides in a controlled manner, but begins to grow uncontrollably. In many cases, this type of gen ... more
Both in materials science and in biomedical research it is important to be able to view minute nanostructures, for example in carbon-fiber materials and bones. A team from the Technical University of Munich (TUM), the University of Lund, Charité hospital in Berlin and the Paul Scherrer Inst ... more
Lecithin plays a vital role in the production of chocolate and many other foods. It's never been clear how this ingredient works on a molecular level, and confectioners have relied on observational methods to perfect their recipes. Now, scientists have shown how the field of molecular dynam ... more
Physicists from Ludwig-Maximilians-Universität, the Max Planck Institute of Quantum Optics and the TU München have developed a method using laser-generated X-rays and phase-contrast X-ray tomography to produce three-dimensional images of soft tissue structures in organisms With laser light ... more
Researchers in an international collaboration at the Paul Scherrer Institute (PSI) have successfully developed a new experimental method to determine a fundamental property of the neutron. Neutrons are parts of atomic nuclei, and thus key building blocks in the matter that surrounds us. Alt ... more
Two scientists working in Europe have paved the way for improved plastic electronics by devising a technique that can be used to take images of plastic mixtures on the nanoscale simultaneously in the body of the material and at the surface. Low-cost plastic solar cells, brighter displays, ... more
Traditional X-ray images can clearly distinguish between bones and soft tissue, with muscles, cartilage, tendons and soft-tissue tumours all look virtually identical. The phase-contrast technique developed a few years ago at the Paul Scherrer Institute enables X-ray images to be produced th ... more
- 1Schleicher & Schuell has been purchased by Whatman plc
- 2LGC rebrands reference standards
- 3Argonne’s lithium-ion battery technology to be commercialized by BASF
- 4Endress+Hauser Set for Complete Acquisition of Analytik Jena
- 5Device combines power of mass spectrometry, microscopy
- 6Agilent Technologies completes acquisition of Seahorse Bioscience
- 7Researchers design and patent graphene biosensors
- 8Thermo Fisher Scientific Scientist Dr. Alexander Makarov Receives Inaugural HUPO Science and Technology Award
- 9Waters Corporation Announces Christopher J. O'Connell as Chief Executive Officer
- 10MDS Sciex Opens Manufacturing Facility in Singapore