By combining this new microfluidic “droplet-on-demand” method with “optical tweezers” that could merge multiple droplets and cause their molecular contents to react, the research may ultimately lead to a compact, integrated setup for obtaining single-molecule information on the structure and function of important organic materials, such as proteins, enzymes, and DNA.
With the aid of NIST’s Center for Nanoscale Science and Technology, physicists Carlos López-Mariscal and Kristian Helmerson created a tiny microfluidic device with a channel through which water can flow. Squeezed into a narrow stream by a mixture of oils whose viscosity, or resistance to flow, exerts pressure on it, the water then enters a narrow constriction. The water’s abrupt pressure drop—accompanied by a dash of detergent—breaks its surface tension, splitting it into small droplets. (This same effect occurs when a thin stream of water falling from a faucet breaks up into small drops.)
The droplet sizes are highly uniform and can be tuned by adjusting the width of the constriction. With this technique, the researchers made droplets about a micrometer in diameter—or half an attoliter (half a billionth of a billionth of a liter) in volume.
In the microfluidic channel, the water is laced with desired molecules of just the right concentration, so that resulting droplets each pick up on average just one molecule of interest. Inside each droplet, the individual molecules of interest slosh around freely in the relatively roomy sphere, along with the water molecules that make up the bulk of every droplet.
By using laser beams, the researchers can move two or more single-molecule-containing droplets, cause them to coalesce, and observe the reactions through optical methods. For their initial reactions, the researchers are mixing fluorescent molecules that emit different colors, but in the future, they envision more interesting chemical reactions, such as those between an infectious agent and an antibody, or a chromosome and a drug. The researchers can shape a laser beam into any desired pattern and thereby trap not only single drops, but arrays of them, opening up new possibilities for single-molecule spectroscopy.
* C. López-Mariscal and K. Helmerson. Optical trapping of hydrosomes. Proc. SPIE, Vol. 7400, 740026 (2009).
Ben Stein | Newswise Science News
Further reports about: > Microdroplets > Molecules > Nanochemistry > chemical reaction > droplet-on-demand > information technology > laser beam > microfluidic > optical tweezer > optical tweezers > organic material > organic materials > single-molecule information > small drops > surface tension > viscosity > water molecule
Not of Divided Mind
19.01.2017 | Hertie-Institut für klinische Hirnforschung (HIH)
CRISPR meets single-cell sequencing in new screening method
19.01.2017 | CeMM Forschungszentrum für Molekulare Medizin der Österreichischen Akademie der Wissenschaften
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
19.01.2017 | Earth Sciences
19.01.2017 | Life Sciences
19.01.2017 | Physics and Astronomy