In order to observe the individual particles in a solution, Prof. Madhavi Krishnan and her co-workers «entice» each particle into an «electrostatic trap». It works like this: between two glass plates the size of a chip, the researchers create thousands of round energy holes. The trick is that these holes have just a weak electrostatic charge. The scientists than add a drop of the solution to the plates, whereupon each particle falls into an energy hole and remains trapped there. But the particles do not remain motionless in their trap. Instead, molecules in the solution collide with them continuously, causing the particles to move in a circular motion. «We measure these movements, and are then able to determine the charge of each individual particle», explains Prof. Madhavi Krishnan.
Put simply, particles with just a small charge make large circular movements in their traps, while those with a high charge move in small circles. This phenomenon can be compared to that of a light-weight ball which, when thrown, travels further than a heavy one. The US physicist Robert A. Millikan used a similar method 100 years ago in his oil drop experiment to determine the velocity of electrically charged oil drops. In 1923, he received the Nobel Prize in physics in recognition of his achievements. «But he examined the drops in a vacuum», Prof. Krishnan explains. «We on the other hand are examining nano particles in a solution which itself influences the properties of the particles».
Electrostatic charge of «nano drugs packages»
For all solutions manufactured industrially, the electrical charge of the nano particles contained therein is also of primary interest, because it is the electrical charge that allows a fluid solution to remain stable and not to develop a lumpy consistency. «With our new method, we get a picture of the entire suspension along with all of the particles contained in it», emphasizes Prof. Madhavi Krishnan. A suspension is a fluid in which miniscule particles or drops are finely distributed, for example in milk, blood, various paints, cosmetics, vaccines and numerous pharmaceuticals. «The charge of the particles plays a major role in this», the Zurich-based scientist tells us.
One example is the manufacture of medicines that have to be administered in precise doses over a longer period using drug-delivery systems. In this context, nano particles act as «packages» that transport the drugs to where they need to take effect. Very often, it is their electrical charge that allows them to pass through tissue and cell membranes in the body unobstructed and so to take effect. «That's why it is so important to be able to measure their charge. So far most of the results obtained have been imprecise», the researcher tells us.
«The new method allows us to even measure in real-time a change in the charge of a single entity», adds Prof. Madhavi Krishnan. «This is particularly exciting for basic research and has never before been possible». This is because changes in charge play a role in all bodily reactions, whether in proteins, large molecules such as the DNA double helix, where genetic make-up is encoded, or cell organelles. «We're examining how material works in the field of millionths of a millimeter».
University of Zurich: http://www.uzh.ch
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
A laser-driven particle accelerator just 9 centimetres long is gearing up to rival heavyweights like the Large Hadron Collider
An inside look at Corning’s labs suggests what’s next for the inventor of Gorilla Glass.Someday your smartphone might be able to help you in a new way when you’re traveling: by telling you whether the water is safe to drink.
Scientists shed light on the energetic emission of radiation that occurs in thunderstorms.
NASA's Mars rover has sniffed out short-lived bursts of methane, but whether it's Martian life or just a geological by-product is still unclear
CERN's Large Hadron Collider will be turned back on in March and a few weeks later will start smashing sub-atomic particles together again at nearly double its previous power, helping scientists hunt for clues about the universe.
The flat disc shape of the Milky Way galaxy had been a mystery. Now simulations suggest it could be thanks to winds driven by charged particles
Understanding the different ways in which birds get their vivid hues could help us make coloured displays for devices such as e-readers
The water and sediment flow might have been massive enough to build a mountain, NASA researchers say.
Liquids come in many forms, from bubbles and droplets to jets and sheets. Henri Lhuissier of Paris Diderot University and his colleagues use high-speed cameras to zoom in on the physics behind all kinds of liquid phenomena, which arise throughout nature, such as in the formation of raindrops and morning dew
There’s still a lot scientists don’t know about the Higgs boson. Now, you can help make the next discovery.