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.
Januar 9, 2009
From Sunday April 5 to Wednesday April 8, 2009 the Focus on Microscopy (FOM) conference will take place in Krakow, Poland. It is the continuation of a yearly conference series presenting the latest innovations in optical microscopy and its application in biology, medicine and the material sciences. Key subjects are the theory and practice of 3D optical imaging, related 3D image processing, and reporting especially on developments in resolution and imaging modalities. The FOM conference also covers the rapidly advancing fluorescence labeling techniques for the confocal and multiphoton 3D imaging of live- biological-specimens. A technical exhibition will be a special feature of this year’s conference in Krakow.
Upcoming topics will cover:
– Confocal and multiphoton-excitation microscopy
– Novel illumination and detection strategies
– Fluorescence: new labels, fluorescent proteins, quantum dots, single molecule
– Time-resolved fluorescence: FRET, FRAP, FLIM, FCS
– Coherent non-linear microscopy: SHG, THG, SFG, CARS
– Raman, light scattering microscopy
– Multi-dimensional imaging
– Sub-wavelength resolution: near field microscopy, STED, PALM
– Laser manipulation, ablation and microdissection, photoactivation
– Optical tools in genomics, proteomics, phenomics, cytometry
– Magnetic resonance and X-ray microscopy
– Image processing and visualization
– Live cell and whole tissue imaging
The conference will take place at the Jagiellonian University Auditorium Maximum, ul. Krupnicza 35, in the center of Krakow.
Details for registration, abstract submission, deadlines, etc. will soon be available on:
Krakow, Poland (source: pixelio.de)