Methods and Applications of Fluorescence

August 14, 2009

The 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

Budapest, Hungary

Localization Microscopy Using GFP

Juli 30, 2009

Scientists at Heidelberg University, Germany have developed a new technique for localization microscopy, the “spectral precision distance microscopy” (SPDM). Using visible light, this method allows a single molecule resolution of celullar structures down to the range of few nanometer, about 20 times better than the conventional optical resolution. The researchers invented a new instrument which is a combination of the world’s fastest nano light microscope for 3D cell analysis and the new SPDM technique. Prof. Christoph Cremer of the Kirchhoff Institute of Physics and his team were able to show that SPDM can be realized by common fluorescent dyes, such as the green fluorescent protein (GFP) which can be switched on and off by means of light, as long as certain photophysical conditions are fulfilled. This can be achieved via the so-called “reversible photobleaching” of the dye. So far, only special fluorescent dyes could be used as temporally convertible light signals. According to Cremer there are millions of specimens containing gene constructs with dyes from the GFP group available in biomedical laboratories all over the world. They could be put into immediate use for this new kind of localization microscopy.

Mobile Phone Microscopy

Juli 23, 2009

Researchers at the University of California, Berkeley, US have developed the CellScope – a new microscope that can be attached to a common mobile phone with a camera to take color images of microorganisms. The CellScope consists of compact microscope lenses fitted in a holder, which is positioned in front of the mobile phones camera. By using an off-the-shelf phone with a 3.2 megapixel camera, the researchers were able to achieve a spatial resolution of 1.2 micrometers. In this way they were able to capture bright field images of Plasmodium falciparum, the parasite that causes malaria in humans and sickle-shaped red blood cells. They were also able to take fluorescent images of Mycobacterium tuberculosis, the bacterium that causes TB in humans. The development of CellScope moves a major step forward in taking clinical microscopy out of specialized laboratories and into field settings for disease screening and diagnoses. “The same regions of the world that lack access to adequate health facilities are, paradoxically, well-served by mobile phone networks,” said Dan Fletcher, UC Berkeley associate professor of bioengineering and head of the research team. “We can take advantage of these mobile networks to bring low-cost, easy-to-use lab equipment out to more remote settings.”

CellScope prototype configured for fluorescent imaging (taken by David Breslauer)

CellScope prototype configured for fluorescent imaging (taken by David Breslauer, UC Berkeley)

The Sound of Light

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.

Multi-spectral opto-acoustic tomography or MSOT allows the investigation of subcellular processes in live organisms.

Principles of Fluorescence Techniques

Juni 24, 2009

The Fluorescence Education Center, also referred to as the Fluorescence Foundation, will host two courses on the principles of fluorescence techniques to be held from:
June 29 – July 2, 2009 in Genova, Italy
September 14-17, 2009 in Madrid, Spain

The Principles of Fluorescence Techniques course will outline the basic concepts of fluorescence techniques and the successful utilization of the currently available commercial instrumentation. The course is designed for students who utilize fluorescence techniques and instrumentation and for researchers and industrial scientists who wish to deepen their knowledge of fluorescence applications. Key scientists in the field will deliver theoretical lectures. The lectures will be complemented by the direct utilization of steady state and lifetime fluorescence instrumentation and confocal microscopy for FLIM and FRET applications.

Topics addressed in this course include:

- Basic Definitions and Principles of Fluorescence
– Fluorescence Polarization
– Time-resolved Fluorescence
– Instrumentation
– Data Manipulation and Data Analysis
– Non-Linear Microscopy Including SHG
– GFP Fluorescence and Photoactivation
– Confocal and Multiphoton Fluorescence Microscopy
– FCS, Fluorescence Correlation Spectroscopy
– FLIM, Fluorescence Lifetime Imaging
– Single Molecule Imaging
– Image Processing and Deconvolution Approaches

Molecular Light Switches for Higher Resolution

Mai 29, 2009

The “Superresolution” research network, founded by the German Ministry of Education and Sciences, demonstrated a new widefield microscopy technology with resolutions better than 20 nanometers. The method is based on special dyes, which’s fluorescence can be optically and reversibly switched on and off in aqueous solutions. The dyes are bond to cellular structures by using a functional group. By switching the dyes on and off, the fluorescence emission is separated in time until only those dye molecules fluoresce that have enough distance to allow their localization as single molecules. After several thousand switching cycles, a total image is constructed (dSTORM – direct stochastic optical reconstruction microscopy). Involved in the project were the work groups of Prof. Dr. M. Sauer and Prof. Dr. J. Mattay (University of Bielefeld, Germany ), Prof. Dr. K.-H. Drexhage (University of Siegen, Germany), Prof. Dr. J. Enderlein (University of Goettingen, Germany), and Prof. Dr. S. Hell (Max Planck Institute of Biophysical Chemistry, Goettingen, Germany).

Cytoskeleton of a fixed cell. Left: Fluorescence image at standard conditions. Right: dSTORM image using molecular switches.

Cytoskeleton of a fixed cell. Left: Fluorescence image at standard conditions. Right: dSTORM image using molecular switches.

Live Cell Imaging at Double the Resolution

Mai 6, 2009

A team of researchers of the University of Georgia (UGA) and the University of California, San Francisco, US has developed a microscope that is capable of live imaging at double the resolution of fluorescence microscopy by using structured illumination. The research was published in Nature Methods on April 26, 2009. “What we’ve done is develop a much faster system that allows you to look at live cells expressing the green fluorescent protein (GFP), which is a very powerful tool for labeling inside the cell,” explained UGA engineer Peter Kner.


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