Described in a new paper,* the JILA technique is faster, more controllable, and less prone to damaging expensive optics or accidentally altering chemistry than conventional methods using electric currents for bulk heating of microscope stages, optics and samples. The demonstration extends a technique used to study single living cells to the field of single-molecule microscopy.
Fast, noncontact heating of very small samples is expected to enable new types of experiments with single molecules. For example, sudden, controlled jumps in temperature could be used to activate molecular processes and observe them in real time.
JILA is jointly operated by the National Institute of Standards and Technology (NIST) and the University of Colorado at Boulder (CU).
The JILA "bathtubs" consist of about 35 picoliters (trillionths of a liter, or roughly one-thirtieth of a nanoliter) of water on a glass slide. Gently focused infrared laser light is used to heat a nanoscale column of water. By moving the laser beam, this column can be made to warm single RNA molecules attached to the slide. The samples are mounted above an inverted fluorescence microscope, used to study folding of tagged RNA molecules (See for example, "JILA Study of RNA Dynamics May Help in Drug Design," NIST Tech Beat, July 13, 2005 at http://www.nist.gov/public_affairs/techbeat/tb2005_0713.htm#JILA). The researchers simultaneously heated and observed folding of the molecules, comparing results obtained with the laser heating technique to measurements obtained with bulk heating.
The heating laser is directed at the samples from above, with the beam focused to a spot size of about 20 micrometers. The near-infrared light is just the right wavelength to excite vibrations in chemical bonds in the water molecules; the vibrations quickly turn into heat. The laser offers a much larger dynamic temperature range (20 to 90 degrees Celsius, or 68 to 194 degrees Fahrenheit) than bulk heating methods, according to the paper. In early trials, the technique controlled bathtub heating to an accuracy of half a degree Celsius in less than 20 milliseconds across a micrometer-scale sample area.
"Exact sizes of the laser beam and sample area don't matter," says NIST/JILA Fellow David Nesbitt, senior author of the paper. "What's important is having time and temperature control over volumes of fluid small enough to be able to look at single molecules."
The research is funded in part by the National Science Foundation, NIST, and the W.M. Keck Foundation initiative in RNA sciences.
* E. D. Holmstrom and D.J. Nesbitt. Real-Time Infrared Overtone Laser Control of Temperature in Picoliter H2O Samples: "Nanobathtubs" for Single Molecule Microscopy. Journal of Physical Chemistry Letters 1, pages 2264-2268. Published online: July 7, 2010
Laura Ost | EurekAlert!
How brains surrender to sleep
23.06.2017 | IMP - Forschungsinstitut für Molekulare Pathologie GmbH
A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
23.06.2017 | Physics and Astronomy
23.06.2017 | Physics and Astronomy
23.06.2017 | Information Technology