Biophysicists often study nanoscale and even picoscale mechanics by using lasers to both apply force to and track the position of fragile biomolecules such as DNA or protein by manipulating a tiny sphere--typically polystyrene--attached to the molecule. The JILA team would like to find new microsphere materials that can be trapped by laser radiation pressure more efficiently, which would enable faster measurements and detection of smaller motions at the same laser power.
As described in the Aug. 15 issue of Optics Letters,* the JILA team demonstrated that 100-nanometer-wide gold beads, as expected because of their metallic nature, can be trapped and detected six times more easily than polystyrene particles of a similar size.
However, the scientists also found that gold absorbs light and heats up quickly, by a remarkable 266 degrees (Celsius) per watt of laser power, at the wavelength most often used in optical traps. Unless very low laser power is used, the heat could damage the molecules under study. Thus, gold beads would not be useful for temperature-sensitive experiments or applying force to molecules. But the heating effect could be useful in raising local temperatures in certain experiments, such as heating a protein just enough to allow scientists to watch it unfold, the paper suggests.
Laura Ost | EurekAlert!
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23.02.2017 | University of Wisconsin-Madison
Prediction: More gas-giants will be found orbiting Sun-like stars
22.02.2017 | Carnegie Institution for Science
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
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Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
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