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November 20, 2009
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Imaging Collagen with X-rays
September 21, 2009Coherent X-ray Diffraction patterns of collagen in soft tissues have been measured for the first time by Dr Felisa Berenguer (London Centre for Nanotechnology) with her colleagues. This development opens doors to better understanding of living tissues like skin and bones, as well as the bio-mineralization processes which turn flexible collagen into semi-flexible cartilage and eventually into rigid bones. In a distant future, the understanding of the collagen structure will eventually lead to cures for of bone diseases, notably osteoporosis, or assist ongoing efforts to develop artificial skin.
Dr Berenguer is part of Prof Ian Robinson’s group in the London Centre for Nanotechnology. This group is developing methods of using the coherence properties of these X-rays for imaging materials on the nanoscale. They use new synchrotron X-ray sources with extremely high brightness such as the Diamond Light Source on the Harwell campus near Oxford. While new light lines at the Diamond Light Source are still under construction, the London Centre Nanotechnology operates one of the experimental out-stations of the Advanced Photon Source (APS), an X-ray synchrotron in Chicago, USA. The group is focusing its efforts on X-rays because this type of light has small wavelengths and is strongly penetrating into material. There is thus an opportunity for imaging physical structures in three dimensions with resolution well beyond that of the visible light microscope. The group is also developing phase-contrast methods that are sensitive to nanoscale strains, or the detailed packing arrangement of molecules in biological tissues.
Original publication:
Berenguer de la Cuesta F, Wenger MP, Bean RJ, Bozec L, Horton MA, Robinson IK. : Coherent X-ray diffraction from collagenous soft tissues. Proc Natl Acad Sci U S A. 2009 Aug 24. [Epub ahead of print]
Diffraction pattern of collagen obtain by Dr Berenguer and al during the scope of this research. Source: London Centre for Nanotechnology
Leave a Comment » | Research & Development | Tagged: Advanced Photon Source, Berenguer, Collagen, Diamond Light Source, Ian Robinson, imaging, London Centre for Nanotechnology, synchrotron X-ray sources | Permalink
Posted by birgitwashburn
Imaging Surface Charges on Individual Biomolecules
September 2, 2009
Kelvin Probe Force Microscopy schematic
Surface charges play a key role in determining the structure and function of proteins, DNA and larger biomolecular structures. For example, negatively charged DNA strands electrostatically interact with histone proteins, transcription factors, or polymerases thereby influencing the read-out of genetic information and the development of cancer. Similarly, the central process of protein folding and protein interaction, often governed by charges, is the major factor in protein-folding diseases such as Alzheimer’s or Parkinson’s Disease. However, thus far there have been no experimental methods to spatially resolve the electrostatic surface potential of individual biological molecules. In general, the investigation of individual molecules can shed light on their dynamic behaviour or on static heterogeneity which is masked in ensemble measurements.
A collaborative effort between researchers from the London Centre for Nanotechnology (Bart W Hoogenboom), King’s College London (Carl Leung, Patrick Mesquida) and UCL Chemistry (Stefan Howorka, Helen Kinns) has led to the first measurements of the electrostatic surface potential of individual DNA and avidin molecules with nanometre resolution using Kelvin Probe Force Microscopy (KPFM) in air.
Kelvin Probe Force Microscopy (KPFM) can measure surface charges by contactless recording of the electrostatic force between a conductive Atomic Force Microscope tip and a biomolecule on a support. To achieve this, the AFM tip is simultaneously excited at its mechanical resonance frequency and by an electrical (AC) voltage. This periodic electrical voltage on the tip leads to a force between the tip and the charges on the biomolecule, which is recorded by means of a lock-in amplifier and nullified by the Kelvin mode feedback by applying a separate DC voltage (not shown). The polarity and magnitude of this DC voltage corresponds to the local surface charge profile (in mV) which is recorded simultaneously with the topography of the biomolecule.
The investigation led at the London Centre for Nanotechnology also show, for the first time, the surface potential of buffer salts shielding DNA molecules on a surface, which would not be possible with conventional ensemble techniques. It is anticipated that the ability to visualize the electrostatic surface potentials of individual proteins and DNA at molecular resolution will be an important tool in fundamental biophysical research and in the fields of biosensing and bio-nanoelectronics.
Original Publication:
Leung C, Kinns H, Hoogenboom BW, Howorka S, Mesquida P. (2009): Imaging surface charges of individual biomolecules. Nano Lett. 2009 Jul;9(7):2769-73.
Leave a Comment » | Research & Development | Tagged: Bart W Hoogenboom, Biomolecules, conductive Atomic Force Microscope tip, imaging, Kelvin Probe Force Microscopy, Kelvin Probe Force Microscopy (KPFM) in air, King’s College London, KPFM, London Centre for Nanotechnology, nanometre resolution | Permalink
Posted by birgitwashburn
To Study Biological Molecules and Structures
August 31, 2009Researchers in the United States and Spain have discovered that a tool widely used in nanoscale imaging works differently in watery environments, a step toward better using the instrument to study biological molecules and structures.
The researchers demonstrated their new understanding of how the instrument – the atomic force microscope – works in water to show detailed properties of a bacterial membrane and a virus called Phi29, said Arvind Raman, a Purdue professor of mechanical engineering. An atomic force microscope uses a tiny vibrating probe to yield information about materials and surfaces on the scale of nanometers, or billionths of a meter. Because the instrument enables scientists to “see” objects far smaller than possible using light microscopes, it could be ideal for studying molecules, cell membranes and other biological structures. The best way to study such structures is in their wet, natural environments. However, the researchers have now discovered that in some respects the vibrating probe’s tip behaves the opposite in water as it does in air, said Purdue mechanical engineering doctoral student John Melcher. The probe is caused to oscillate by a vibrating source at its base. However, the tip of the probe oscillates slightly out of synch with the oscillations at the base. This difference in oscillation is referred to as a “phase contrast,” and the tip is said to be out of phase with the base.
Although these differences in phase contrast reveal information about the composition of the material being studied, data can’t be properly interpreted unless researchers understand precisely how the phase changes in water as well as in air, Raman said.
If the instrument is operating in air, the tip’s phase lags slightly when interacting with a viscous material and advances slightly when scanning over a hard surface. Now researchers have learned the tip operates in the opposite manner when used in water: it lags while passing over a hard object and advances when scanning the gelatinous surface of a biological membrane.
Researchers deposited the membrane and viruses on a sheet of mica. Tests showed the differing properties of the inner and outer sides of the membrane and details about the latticelike protein structure of the membrane. Findings also showed the different properties of the balloonlike head, stiff collar and hollow tail of the Phi29 virus, called a bacteriophage because it infects bacteria.
Original Publication:
Melcher J, Carrasco C, Xu X, Carrascosa JL, Gómez-Herrero J, José de Pablo P, Raman A. (2009): Origins of phase contrast in the atomic force microscope in liquids. Proc Natl Acad Sci U S A. 2009 Aug 18;106(33):13655-60. Epub 2009 Aug 5.
Researchers in the United States and Spain have discovered that an atomic force microscope - a tool widely used in nanoscale imaging - works differently in watery environments, a step toward better using the instrument to study biological molecules and structures. The researchers demonstrated their new understanding of how the instrument works in water to show details of the mechanical properties of a virus called Phi29. The images in "a" and "c" show the topography, and the image in "b" shows the different stiffness properties of the balloonlike head, stiff collar and hollow tail of the Phi29 virus, called a bacteriophage because it infects bacteria. (C. Carrasco-Pulido, P. J. de Pablo, J. Gomez-Herrero, Universidad Autonoma de Madrid, Spain)
Leave a Comment » | Research & Development | Tagged: Arvind Raman, atomic force miscorscopy, biological, cells, imaging, John Melcher, Melcher, microscopy, molecules, nanoscale, phase contrast, Purdue, raman, watery | Permalink
Posted by birgitwashburn
Methods and Applications of Fluorescence
August 14, 2009The 11th International Conference on Methods and Applications of Fluorescence: Spectroscopy, Imaging and Probes will be held in Budapest, Hungary, from September 6-9, 2009. The venue of the Conference is the Congress Center of the oldest Hungarian University, the Eötvös Loránd University.
The meeting will cover the following scientific topics:
- Fluorescence Spectroscopy (Theory and Applications)
- Fluorescence Correlation and Single Molecule Spectroscopy
- Fluorescence in Biology/Medicine: Bioassays, Biophysics
- Special Fluorescent Imaging Techniques: Multi-Photon, Live Cell and Single Molecule Imaging
- Novel Fluorescent Probes, Sensors, Fluorescent Proteins, Quantum Dots, Nanomaterials and their Applications
- Special Fluorescence Techniques: Upconversion, Delayed Fluorescence, Fast Fluorescence Kinetics FRET, etc.
- Fluorescence Microscopy: Towards Higher Spatial and Temporal Resolution
- Fluorescence in Systems Biology High Throughput Screening Assays, Arrays, Micro-chip
Budapest, Hungary
Leave a Comment » | Events | Tagged: applications, bioassays, biophysics, Budapest, conference, Eötvös Loránd University, fluorescence, FRET, imaging, live cell imaging, Methods and Applications of Fluorescence: Spectroscopy, molecules, probes, spectroscopy, upconversion | Permalink
Posted by aszerdi
3D Movies of Microscopic Systems
July 29, 2009Physicists 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.
www.nyu.edu
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.
Leave a Comment » | Research & Development | Tagged: 3D, beam, collimated, dark, David Grier, digital, Grier, hologram, holographic, holography, illumination, illuminator, images, imaging, interference, lasers, light, Lorenz-Mie, microscopic, microscopy, mole, molecules, movies, New York University, NYU, objects, overlapping, patterns, recording, scattering, snapshots, systems, theory, three-dimensional, video | Permalink
Posted by aszerdi
Euro-BioImaging: First Stakeholder Meeting
July 17, 2009From September 21-22, 2009 the first stakeholder meeting of Euro-BioImaging will take place at the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany. The goal of Euro-BioImaging project is to establish a pan-European imaging infrastructure for biological and medical research. It will provide access to state of the art imaging technologies, training and a continuous development of imaging research technologies. The aim of the stakeholder meeting is to gather eminent representatives of the scientific community, funding and governmental organisations, and industry with particular interest in biomedical imaging and to discuss potential participation as well as the content and structure of this infrastructure project. Register online at:
www.embl.de/conferences/eurobioimaging
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FEI Joins Metrology Research at University of Albany
July 15, 2009FEI Company, a provider of atomic-scale imaging and analysis systems, and Sematech, the global consortium of chipmakers, announced that FEI has joined Sematech’s Advanced Metrology Development Program at the College of Nanoscale Science and Engineering (CNSE) of the University at Albany, US. As a member of this program, FEI will collaborate with experts to develop high-resolution capabilities of transmission electron microscopy (TEM) analysis, with electron energy loss spectroscopy (EELS) and focused ion beam (FIB) technology to address critical needs in process development and defect analysis.
www.fei.com
www.cnse.albany.edu
www.sematech.org
Leave a Comment » | Collaboration | Tagged: advanced metrology program, Albany, atomic, atomic-scale, chipmakers, CNSE, College of Nanoscale Science and Engineering, development, EELS, electron, electron energy loss spectroscopy, energy, FEI, FIB, focused, focused ion beam, high-resolution, imaging, ions, loss, metrology, microscopy, nanoscale, Sematech, spectroscopy, TEM, transmission electron microscopy, transmissions, University of Albany | Permalink
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First Taiwan AFM Bioworkshop
June 30, 2009Asylum Research, in conjunction with the National Health Research Institutes (NHRI), will host the first Taiwan AFM Bioworkshop to be held July 30-31, 2009 at NHRI, Zhunan Campus, in Taiwan. The workshop will combine talks from leading researchers and industry experts on atomic force microscopy for life science applications, as well as instructional AFM demonstrations. Topics covered include principles of AFM, biological imaging, force spectroscopy, integration of AFM and optical microscopy, sample preparation, application examples and future directions in AFM. The event is free to all researchers in the field of AFM.
www.asylumresearch.com/bioworkshop
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Fellow for the Microscopy Society of America
June 26, 2009Yimei Zhu, a scientist at the U.S. Department of Energy’s Brookhaven National Laboratory, has been elected the inaugural Fellow of the Microscopy Society of America, an affiliate of the American Institute of Physics and the American Association for the Advancement of Science. Limited to a small fraction of members, the designation of Fellow recognizes senior distinguished members of the society who have made significant contributions to the advancement of the science and practice of microscopy. Zhu will formally be awarded the society’s first fellowship at its annual meeting in Richmond, Virginia, US, to be held in July. His citation reads: “For outstanding and innovative development and implementation of advanced electron microscopy techniques including quantitative diffraction, imaging, spectroscopy, and phase retrieval methods in understanding superconducting, ferromagnetic, and strongly correlated materials.”
www.bnl.gov
Yimei Zhu, inaugural fellow of the Microscopy Society of America (photo: Courtesy of Brookhaven National Laboratory)
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