Scientists discover the origin of a mysterious force

Feb 28, 2005
Scientists discover the origin of a mysterious force

Scientists at the Universitat Autònoma de Barcelona and Imperial College London have discovered the origin of hydration force, a phenomenon that causes some complex chemical and biochemical species (including DNA and other electrostatically charged molecules) to repel at short distances when surrounded by water. Through this research, improvements could be made to the design of chemical products used in the chemical, pharmaceutical and food industry.

Ever since the 1970s, scientists have been trying to establish the cause of a repulsive force occurring between different electrostatically charged molecules, such as DNA and other biomolecules, when they are very close to each other in aqueous media. This force became know as hydration force.

Jordi Faraudo, a researcher for the Department of Physics at the Universitat Autònoma de Barcelona, and Fernando Bresme of the Department of Chemistry at Imperial College London have studied this mysterious force in detail and have discovered where its origins lie.

In the same way that a flag flutters in the direction the wind is blowing, at a microscopic level water molecules are gently attracted towards the direction in which an electric field is pointing. However, when the water is in contact with surfaces that create small electric fields, such as chemical compounds like those found in many detergents, this is no longer the case: the water molecules have a remarkable capacity to organise themselves into complex structures that are strongly orientated in such a way as to cancel out the electric field, and on some occasions, to reverse it. This abnormal behaviour was discovered by the same researchers and published in Physical Review Letters in April 2004.

The scientists have now discovered that this strange property is responsible for the hydration force that acts when water is surrounded by certain types of electrostatically charged molecules, such as DNA and some biological compounds, and when thin films form in detergents. The discovery has been published in today’s edition of Physical Review Letters.

Water is the solvent in which most physical, chemical and biological processes take place. Therefore, it is essential to understand the nature of interactions between molecules dissolved in water in order to understand many of these processes. Two of the most important of these processes are the adherence of substances to cell membranes and the withdrawal of proteins. Both of these are fundamental in biomedical research, since a substantial part of the process of designing new drugs is based on understanding how substances penetrate cell membranes to enter cells. These drugs are often proteins designed to prevent or strengthen the action of other substances. In these cases, accurately identifying the protein folding is essential, since the form these proteins take on when they fold influences how effectively they are able to act.

Fully understanding the properties of this force that occurs when molecules surrounded by water adhere to each other is also useful in the chemical industry, particularly when involving mechanisms in which colloidal suspensions must be stabilised, such as the mechanisms used to produce paints, cosmetics and food products such as yoghurt and mayonnaise.

Source: Universitat Autònoma de Barcelona

Explore further: Physicist's Nobel Prize up for auction, $325,000 to start

Related Stories

Nature inspires first artificial molecular pump

May 19, 2015

Using nature for inspiration, a team of Northwestern University scientists is the first to develop an entirely artificial molecular pump, in which molecules pump other molecules. This tiny machine is no small ...

A conversation with astronomer Dimitri Mawet

May 18, 2015

Associate Professor of Astronomy Dimitri Mawet has joined Caltech from the Paranal Observatory in Chile, where he was a staff astronomer for the Very Large Telescope. After earning his PhD at the University ...

'Supercool' material glows when you write on it

May 13, 2015

A new material developed at the University of Michigan stays liquid more than 200 degrees Fahrenheit below its expected freezing point, but a light touch can cause it to form yellow crystals that glow under ...

A tale of two roads into protein unfolding

May 11, 2015

You are taking a class on origami and Mr. Otaki asks you to fold that little red piece of paper into a very elaborate design. You have to do it in a very short time. You try your best but you fail. Your origami ...

Recommended for you

On-demand X-rays at synchrotron light sources

7 hours ago

Consumers are now in the era of "on-demand" entertainment, in which they have access to the books, music and movies they want thanks to the internet. Likewise, scientists who use synchrotron light sources ...

Squeezed quantum cats

9 hours ago

ETH professor Jonathan Home and his colleagues reach deep into their bag of tricks to create so-called 'squeezed Schrödinger cats.' These quantum systems could be extremely useful for future technologies.

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

LyoDave
not rated yet Oct 14, 2008
Better read about Jacob Israelachvili's latest experiments on the "hydration force". Jacob now says the whole thing is an experimental artefact. Or more precisely, a fundamental misinterpretation of force box apparatus experimental results. Seeing as how Jacob has been at the very center of this debate since the beginning, one has to take this very seriously.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.