Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New equation predicts molecular forces in hydrophobic interactions

12.10.2011
New equation developed by UCSB chemical engineers solves the mystery of forces between water-repelling and water-attracting molecules that are critical to industrial and medical applications

The physical model to describe the hydrophobic interactions of molecules has been a mystery that has challenged scientists and engineers since the 19th century. Hydrophobic interactions are central to explaining why oil and water don't mix, how proteins are structured, and what holds biological membranes together. Chemical engineering researchers at UC Santa Barbara have developed a novel method to study these forces at the atomic level, and have for the first time defined a mathematical equation to measure a substance's hydrophobic character.

"This discovery represents a breakthrough that is a culmination of decades of research," says Professor Jacob Israelachvili. "The equation is intended to be a tool for scientists to begin quantifying and predicting molecular and surface forces between organic substances in water."

Using a light-responsive surfactant – a soap-like molecule related to fats and lipids – the researchers developed an innovative technique to measure or change the forces between layers of the molecule in water by using beams of UV or visible light. The result is a general equation that applies to even more complicated systems, such as cellular membranes or proteins.

"We were fortunate to find the right combination of experimental methods and theory," said Brad Chmelka, UCSB Chemical Engineering professor and co-author of the study. "The keys to our research were using a light-responsive surfactant molecule, a means of measuring these delicate surface forces, and applying knowledge of what to look for."

The highly-sensitive instrument they used to sense these molecular-level hydrophobic forces, called a surface forces apparatus, is a now-standard technique that was originally pioneered by Israelachili and colleagues in the 1970s.

"In basic chemistry, students learn about van der Waal forces – the weak forces that act between all molecules. That theory was developed more than 100 years ago," explains Professor Israelachvili.

"According to the van der Waals theory, however, oil and water shouldn't separate and surfactants shouldn't form membranes, but they do. There has been no proven theory to account for these special hydrophobic interactions. Such behaviors are crucial for life as we know it to exist."

Hydrophobic and hydrophilic interactions are central to the disciplines of chemistry, physics, and biology that have fueled modern developments in industries from detergents to pharmaceuticals and new biotechnologies. The new equation is expected to impact applications in water filtration, membrane separations, biomedical research, gene therapy methods, biofuel production, and food chemistry.

Virus and disease propagation in the human body are directly linked to hydrophobic properties on a cellular level. One of the problems related to chemotherapy treatments for cancer is being able to direct a drug specifically to cancer cells, instead of the entire body. Israelachvili and his colleagues foresee their discovery having an impact in biomedical research that attempts to understand and treat diseases.

"Cell membranes are complex and discriminating structures, allowing the transmission of various signals into cells and mediating specific interactions with bacteria and viruses," said Jean Chin, Ph.D., who oversees membrane structure grants at the National Institute of General Medical Sciences of the National Institutes of Health. "This study, by enhancing our understanding of the role played by hydrophobic forces in membrane dynamics, will expand what we know about membrane structure and function, as well as microbial infection pathways."

"Understanding how water and oil-like substances interact is enormously important for explaining the properties and functions of many biological and engineering materials," says Dr. Robert Wellek, Program Director in the Directorate for Engineering at the National Science Foundation. "The UCSB and USC teams have elegantly combined concepts from synthetic chemistry, photophysics, and chemical engineering to unravel and quantify the elusive hydrophobic interaction. NSF is very pleased that its grantees have been able to contribute important fundamental knowledge in this important area."

Details of the research were published this month in the Proceedings of the National Academy of Sciences. Their research was made possible by support from the National Science Foundation, the National Institutes of Health, and the Procter & Gamble Company.

"We've known for a long time what we were aiming for. It's a bit like climbing a mountain," said Professor Israelachvili. "The whole thing started at the very bottom. I've been searching for the keys to this interaction for thirty years. We are thrilled with the findings, but it took a lot of steps over carefully chosen paths to get there."

Professor Jacob Israelachvili, Professor Bradley Chmelka, and Stephen Donaldson, Ph.D. student, are with the Department of Chemical Engineering at UCSB. Dr. Israelachvili is a Fellow of the Royal Society of London and member of the U.S. National Academy of Science and the U.S. National Academy of Engineering. Dr. Israelachvili received his Ph.D. in Physics from University of Cambridge and joined UCSB in 1986. He was recently named by the American Institute of Chemical Engineers as one of the "100 Chemical Engineers of the Modern Era" for his achievement and leadership in the field.

Melissa Van De Werfhorst | EurekAlert!
Further information:
http://www.ucsb.edu

More articles from Life Sciences:

nachricht New study finds distinct microbes living next to corals
22.05.2019 | Woods Hole Oceanographic Institution

nachricht Summit charts a course to uncover the origins of genetic diseases
22.05.2019 | DOE/Oak Ridge National Laboratory

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Self-repairing batteries

UTokyo engineers develop a way to create high-capacity long-life batteries

Engineers at the University of Tokyo continually pioneer new ways to improve battery technology. Professor Atsuo Yamada and his team recently developed a...

Im Focus: Quantum Cloud Computing with Self-Check

With a quantum coprocessor in the cloud, physicists from Innsbruck, Austria, open the door to the simulation of previously unsolvable problems in chemistry, materials research or high-energy physics. The research groups led by Rainer Blatt and Peter Zoller report in the journal Nature how they simulated particle physics phenomena on 20 quantum bits and how the quantum simulator self-verified the result for the first time.

Many scientists are currently working on investigating how quantum advantage can be exploited on hardware already available today. Three years ago, physicists...

Im Focus: Accelerating quantum technologies with materials processing at the atomic scale

'Quantum technologies' utilise the unique phenomena of quantum superposition and entanglement to encode and process information, with potentially profound benefits to a wide range of information technologies from communications to sensing and computing.

However a major challenge in developing these technologies is that the quantum phenomena are very fragile, and only a handful of physical systems have been...

Im Focus: A step towards probabilistic computing

Working group led by physicist Professor Ulrich Nowak at the University of Konstanz, in collaboration with a team of physicists from Johannes Gutenberg University Mainz, demonstrates how skyrmions can be used for the computer concepts of the future

When it comes to performing a calculation destined to arrive at an exact result, humans are hopelessly inferior to the computer. In other areas, humans are...

Im Focus: Recording embryonic development

Scientists develop a molecular recording tool that enables in vivo lineage tracing of embryonic cells

The beginning of new life starts with a fascinating process: A single cell gives rise to progenitor cells that eventually differentiate into the three germ...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

Summit charts a course to uncover the origins of genetic diseases

22.05.2019 | Life Sciences

New study finds distinct microbes living next to corals

22.05.2019 | Life Sciences

Stellar waltz with dramatic ending

22.05.2019 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>