Juli 29, 2009
Physicists at New York University (NYU), US have developed a technique to record three-dimensional movies of microscopic systems, such as biological molecules, through holographic video. The technique, developed in the laboratory of NYU Physics Professor David Grier, is comprised of two components: making and recording the images of microscopic systems and then analyzing these images. To generate and record images, the researchers created a holographic microscope. It is based on a conventional light microscope, which uses a collimated laser beam instead of on an incandescent illuminator.
When an object is placed into path of the microscope’s beam, the object scatters some of the beam’s light into a complex diffraction pattern. The scattered light overlaps with the original beam to create an interference pattern reminiscent of overlapping ripples in a pool of water. The microscope then magnifies the resulting pattern of light and dark and records it with a conventional digital video recorder. Each snapshot in the resulting video stream is a hologram of the original object. Unlike a conventional photograph, each holographic snapshot stores information about the three-dimensional structure and composition of the object that created the scattered light field. The recorded holograms appear as a pattern of concentric light and dark rings.
For analyzing the images the researchers based their work on a quantitative theory, the Lorenz-Mie theory, which maintains that the way light is scattered can reveal the size and composition of the object that is scattering it.
The application of the technique ranges from research in fundamental statistical physics to analyzing the composition of fat droplets in milk.
In the microscope, a laser beam illuminates the sample. Light scattered by the sample creates an interference pattern which is magnified and recorded. Then measurements of the particle’s position, size, and refractive index are obtained.
Juli 1, 2009
Together with his research team, Professor Vasilis Ntziachristos from the Helmholtz Zentrum Munich, Germany and the Technical University Munich, Germany developed a new technology to make light audible. The technique, called multi-spectral opto-acoustic tomography (MSOT), combines light and ultrasound to visualize fluorescent proteins that are seated several centimeters deep into living tissue.
The researchers used a genetically modified adult zebra fish which carried fluorescent pigments in its tissue. They illuminated the fish from multiple angles using flashes of laser light that are absorbed by the fluorescent pigments in the fish. The pigments absorb the light, a process that causes slight local increases of temperature, which in turn result in tiny local volume expansions. This happens very quickly and creates small shock waves. In effect, the short laser pulse gives rise to an ultrasound wave that the researchers pick up with an ultrasound microphone. To analyze the resulting acoustic patterns, a computer is attached. The computer uses specially developed mathematical formulas to evaluate and interpret the specific distortions caused by scales, muscles, bones and internal organs to generate a three-dimensional image. In the future this technology may facilitate the examination of tumors or coronary vessels in humans.
Multi-spectral opto-acoustic tomography or MSOT allows the investigation of subcellular processes in live organisms.
Juni 3, 2009
3D Microscopy, taking place from July 12 -16, 2009 in Interlaken, Switzerland, is an international symposium focused on 3D imaging and spectroscopy in science. The objective of this symposium is to create a forum for researchers with different expertise and scientific interests to present their knowhow and the techniques they use to answer their scientific questions. Methods using three-dimensional imaging and spectroscopy to retrieve data in volume will be discussed, whether “light”, x-rays, electrons or near field probes are used. The conference contains 3 plenary talks and 9 sessions with invited and contributed talks and poster sessions.
Session topics are:
– High resolution TEM and AFM
– 3D CLSM and light microscopy
– 3D TEM and atom probe tomography/serial sectioning
– 3D correlative microscopy
– 3D X-ray microscopy and tomography
– 3D FIB/SEM or serial sectioning (with Denk-method) blockface tomography
– 3D image analysis and simulation
– 3D scanning probe microscopy
April 24, 2009
The European Microbeam Analysis Society (EMAS) will hold its 11th annual workshop on „Modern Developments and Applications in Microbeam Analysis“ from May 10-14, 2009 in Gdynia/Rumia, Gdansk, Poland. The main topics are electron probe microanalysis, micro- and nanoanalysis in the natural resources industry, fast energy-dispersive X-ray spectrometry, electron backscatter diffraction, and three-dimensional microanalysis. Time will also be devoted to problem orientated application of microbeam analysis techniques in fields such as catalysts, composites, glass, sensors, and in cultural heritage, environment, forensics, geology, mineralogy, metallurgy, microelectronics, surfaces and interfaces. The event will take place at the Hotel Spa Faltom, Gdynia/Rumia, Gdansk.
City of Gdansk, Poland (source: pixelio.de)
März 20, 2009
A team of researchers led by professor Rafael Piestun of the department of electrical and computer engineering at the University of Colorado and William E. Moerner, professor of chemistry at Stanford University, have demonstrated for the first time a method for three-dimensional optical imaging of objects smaller than 20 nanometers over a wide spatial range. Optical imaging at these scales is of great interest in biomedical sciences and nanotechnology. The new findings, which provide a powerful tool for the super resolution of single molecules, have implications for characterizing defects in materials, the characterization of nanostructures, and the three-dimensional, biophysical and biomedical imaging of tagged molecules inside and outside of cells.
3D single molecule imaging