Thursday, February 9, 2012

Scientists produce world's first magnetic soap

 Scientists from Bristol University have developed a soap, composed of iron rich salts dissolved in water, that responds to a magnetic field when placed in solution. The soap’s magnetic properties were shown with neutrons at the Institut Laue-Langevin to result from tiny iron-rich clumps that sit within the watery solution. The generation of this property in a fully functional soap could calm concerns over the use of soaps in oil-spill clean ups and revolutionise industrial cleaning products.

Scientists have long been searching for a way to control soaps (or surfactants as they are known in industry) once they are in solution to increase their ability to dissolve oils in water and then remove them from a system. The team at Bristol University have previously worked on soaps sensitive to light, carbon dioxide or changes in pH, temperature or pressure. Their latest breakthrough, reported in Angewandte Chemie, is the world’s first soap sensitive to a magnetic field.

Ionic liquid surfactants, composed mostly of water with some transition metal complexes (heavy metals like iron bound to halides such as bromine or chlorine) have been suggested as potentially controllable by magnets for some time, but it had always been assumed that their metallic centres were too isolated within the solution, preventing the long-range interactions required to be magnetically active.

The team at Bristol, lead by Professor Julian Eastoe produced their magnetic soap by dissolving iron in a range of inert surfactant materials composed of chloride and bromide ions, very similar to those found in everyday mouthwash or fabric conditioner. The addition of the iron creates metallic centres within the soap particles.

To test its properties, the team introduced a magnet to a test tube containing their new soap lying beneath a less dense organic solution. When the magnet was introduced the iron-rich soap overcame both gravity and surface tension between the water and oil, to levitate through the organic solvent and reach the source of the magnetic energy, proving its magnetic properties.

Once the surfactant was developed and shown to be magnetic, Prof Eastoe’s team took it to the Institut Laue-Langevin, the world’s flagship centre for neutron science, and home to the world’s most intense neutron source, to investigate the science behind its remarkable property.

When surfactants are added to water they are known to form tiny clumps (particles called micelles). Scientists at ILL used a technique called “small angle neutron scattering (SANS)” to confirm that it was this clumping of the iron-rich surfactant that brought about its magnetic properties.

Dr Isabelle Grillo, responsible of the Chemistry Laboratories at ILL: “The particles of surfactant in solution are small and thus difficult to see using light but are easily revealed by SANS which we use to investigate the structure and behaviour of all types of materials with typical sizes ranging from the nanometer to the tenth of micrometer.”

The potential applications of magnetic surfactants are huge. Their responsiveness to external stimuli allows a range of properties, such as their electrical conductivity, melting point, the size and shape of aggregates and how readily its dissolves in water to be altered by a simple magnetic on and off switch. Traditionally these factors, which are key to the effective application of soaps in a variety of industrial settings, could only be controlled by adding an electric charge or changing the pH, temperature or pressure of the system, all changes that irreversibly alter the system composition and cost money to remediate.

Its magnetic properties also makes it easier to round up and remove from a system once it has been added, suggesting further applications in environmental clean ups and water treatment. Scientific experiments which require precise control of liquid droplets could also be made easier with the addition of this surfactant and a magnetic field.

Professor Julian Eastoe, University of Bristol: “As most magnets are metals, from a purely scientific point of view these ionic liquid surfactants are highly unusual, making them a particularly interesting discovery. From a commercial point of view, though these exact liquids aren’t yet ready to appear in any household product, by proving that magnetic soaps can be developed, future work can reproduce the same phenomenon in more commercially viable liquids for a range of applications from water treatment to industrial cleaning products.”

Peter Dowding an industrial chemist, not involved in the research: “Any systems which act only when responding to an outside stimulus that has no effect on its composition is a major breakthrough as you can create products which only work when they are needed to. Also the ability to remove the surfactant after it has been added widens the potential applications to environmentally sensitive areas like oil spill clean ups where in the past concerns have been raised.”

Story Source:

The above story is reprinted from materials provided by Institut Laue-Langevin (ILL), via AlphaGalileo.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

Paul Brown, Alexey Bushmelev, Craig P. Butts, Jing Cheng, Julian Eastoe, Isabelle Grillo, Richard K. Heenan, Annette M. Schmidt. Magnetic Control over Liquid Surface Properties with Responsive Surfactants. Angewandte Chemie International Edition, 2012; DOI: 10.1002/anie.201108010

Protein purification alternatives

Protein purification, often referred to as downstream processing, is the most costly and time-consuming process in the manufacture of bio-molecules. EU-funded researchers integrated materials science with process development to produce novel low-cost materials and methods for selective purification with a focus on chromatography, membrane separation and extraction.

Purification is somewhat like passing sand and pebbles through a sieve except that separation is not dependent on gravity and relative size of components and holes. Instead, separation depends on chemical and electrical interactions between the biological fluid and specific binders (ligands) through which it passes.

Among the many proteins purified by the pharmaceutical industry are human immunoglobulin G (IgG) and monoclonal antibodies (MAbs), both important in immunity and thus disease therapy. The most common method for purifying IgG and MAbs is the use of protein A resin. However, pharmaceutical companies are increasingly concerned about the supply of protein A materials.

The 'Advanced interactive materials by design' (AIMS) project thus sought to develop alternatives to protein A technology for the purification of proteins. The investigators developed excellent modelling tools enabling assessment of interactions among support, linker, ligand and product promoting efficient and effective design of new materials.

The researchers created a new SartoAims protein A affinity membrane with enhanced affinity for IgG, providing an important alternative to protein A for IgG purification. In addition, the investigators studied two alternatives to protein A technology for purification of MAbs, one using much less expensive ion exchange resins in a Multicolumn Countercurrent Solvent Gradient Purification (MCSGP) form of chromatography and one using aqueous two-phase extraction.

The researchers also developed new materials for use in ion exchange chromatography, a technique that relies on charge interactions for separation. In fact, the chromatographic resin FractoAims demonstrated superior mechanical stability and can be tailor-made based on bead size, pore size, surface area and ligand density.

The new process concepts were tested in a mini-plant to evaluate performance with respect to protein A technology. A combination of two MCSGP units operating with different parameters enabled reduction in operating costs by a factor of three in total MAb purification costs.

The AIMS project outcomes will have significant impact on the protein purification process that has until now been the most costly part of bio-molecule development in the pharmaceutical, chemical and biotechnology industries. Commercialisation of the new technologies promises to improve the European position in the huge global chemicals and pharmaceuticals market.

Story Source:

The above story is reprinted from materials provided by CORDIS Features, formerly ICT Results, via AlphaGalileo.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Metadynamics technique offers insight into mineral growth and dissolution

By using a novel technique to better understand mineral growth and dissolution, researchers at the Department of Energy's Oak Ridge National Laboratory are improving predictions of mineral reactions and laying the groundwork for applications ranging from keeping oil pipes clear to sequestering radium.

The mineral barite was examined to understand mineral growth and dissolution generally, but also because it is the dominant scale-forming mineral that precipitates in oil pipelines and reservoirs in the North Sea. Oil companies use a variety of compounds to inhibit scale formation, but a better understanding of how barite grows could enable them to be designed more efficiently.

Additionally, barium can trap radium in its crystal structure, so it has the potential to contain the radioactive material.

In a paper featured on this month's cover of the Journal of the American Chemical Society, the ORNL-led team studied barite growth and dissolution using metadynamics, a critical technique that allows researchers to study much slower reactions than what is normally possible.

"When a mineral is growing or dissolving, you have a hard time sorting out which are the important reactions and how they occur because there are many things that could be happening on the surface," said Andrew Stack, ORNL geochemist and lead author on the paper. "We can't determine which of many possible reactions are controlling the rate of growth."

To overcome this hurdle, ORNL Chemical Sciences Division's Stack started with molecular dynamics, which can simulate energies and structures at the atomic level. To model a mineral surface accurately, the researchers need to simulate thousands of atoms. To directly measure a slow reaction with this many atoms during mineral growth or dissolution might take years of supercomputer time. Metadynamics, which builds on molecular dynamics, is a technique to "push" reactions forward so researchers can observe them and measure how fast they are proceeding in a relatively short amount of computer time.

With the help of metadynamics, the team determined that there are multiple intermediate reactions that take place when a barium ion attaches or detaches at the mineral surface, which contradicts the previous assumption that attachment and detachment occurred all in a single reaction.

"Without metadynamics, we would never have been able to see these intermediates nor determine which ones are limiting the overall reaction rate," Stack said.

To run computer simulations of mineral growth, researchers used the Large-scale Atomic/Molecular Massively Parallel Simulator, a molecular dynamics code developed by Sandia National Laboratories. Co-authors on the paper are the Curtin University (Australia) Nanochemistry Research Institute's Paolo Raiteri and Julian Gale.

In a podcast ( from the American Chemical Society, Andrew Stack talks about his metadynamics research.

The research was sponsored by the DOE Office of Science. ORNL is managed by UT-Battelle for the Department of Energy's Office of Science.

Story Source:

The above story is reprinted from materials provided by DOE/Oak Ridge National Laboratory.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

Andrew G. Stack, Paolo Raiteri, Julian D. Gale. Accurate Rates of the Complex Mechanisms for Growth and Dissolution of Minerals Using a Combination of Rare-Event Theories. Journal of the American Chemical Society, 2012; 134 (1): 11 DOI: 10.1021/ja204714k

Chemists synthesize artificial cell membrane

Chemists have taken an important step in making artificial life forms from scratch. Using a novel chemical reaction, they have created self-assembling cell membranes, the structural envelopes that contain and support the reactions required for life.

Neal Devaraj, assistant professor of chemistry at the University of California, San Diego, and Itay Budin, a graduate student at Harvard University, report their success in the Journal of the American Chemical Society.

"One of our long term, very ambitious goals is to try to make an artificial cell, a synthetic living unit from the bottom up -- to make a living organism from non-living molecules that have never been through or touched a living organism," Devaraj said. "Presumably this occurred at some point in the past. Otherwise life wouldn't exist."

By assembling an essential component of earthly life with no biological precursors, they hope to illuminate life's origins.

"We don't understand this really fundamental step in our existence, which is how non-living matter went to living matter," Devaraj said. "So this is a really ripe area to try to understand what knowledge we lack about how that transition might have occurred. That could teach us a lot -- even the basic chemical, biological principles that are necessary for life."

Molecules that make up cell membranes have heads that mix easily with water and tails that repel it. In water, they form a double layer with heads out and tails in, a barrier that sequesters the contents of the cell.

Devaraj and Budin created similar molecules with a novel reaction that joins two chains of lipids. Nature uses complex enzymes that are themselves embedded in membranes to accomplish this, making it hard to understand how the very first membranes came to be.

"In our system, we use a sort of primitive catalyst, a very simple metal ion," Devaraj said. "The reaction itself is completely artificial. There's no biological equivalent of this chemical reaction. This is how you could have a de novo formation of membranes."

They created the synthetic membranes from a watery emulsion of an oil and a detergent. Alone it's stable. Add copper ions and sturdy vesicles and tubules begin to bud off the oil droplets. After 24 hours, the oil droplets are gone, "consumed" by the self-assembling membranes.

Although other scientists recently announced the creation of a "synthetic cell," only its genome was artificial. The rest was a hijacked bacterial cell. Fully artificial life will require the union of both an information-carrying genome and a three-dimensional structure to house it.

The real value of this discovery might reside in its simplicity. From commercially available precursors, the scientists needed just one preparatory step to create each starting lipid chain.

"It's trivial and can be done in a day," Devaraj said. "New people who join the lab can make membranes from day one."

The National Institute of Biomedical Imaging and Bioengineering supported this work. UC San Diego has filed a patent application on this discovery.

Story Source:

The above story is reprinted from materials provided by University of California - San Diego. The original article was written by Susan Brown.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

Itay Budin, Neal K. Devaraj. Membrane Assembly Driven by a Biomimetic Coupling Reaction. Journal of the American Chemical Society, 2012; 134 (2): 751 DOI: 10.1021/ja2076873