Tiny molecular "containers" that can take up other molecules as "guests" are of particular interest for technology and science, as catalysts, micro-reaction-chambers, transport containers for pharmaceutical agents, or protective covers for unstable molecules. Various strategies have now been established for building such miniature capsules. Ivan Huc and Joachim Garric (European Institute of Chemistry and Biology, Pessac), as well as Jean-Michel Léger (Laboratoire de Pharmacochimie, Bordeaux) have now developed a novel approach.
The French chemists synthesized a strand-like molecule from aromatic amine building blocks -- nitrogen-containing carbon rings. The building blocks are chosen so that the ribbon curls into a helix. The crucial trick is that the helix is not even: it has a significantly larger diameter in the middle than at the ends. The researchers can precisely control the inner diameter by the selection of individual building blocks and the precise arrangement of the nitrogen atoms within the ring system. They thus select correspondingly different building blocks for the middle and end sections of the spiral ribbon. This results in a helix with a real bubble in the middle and ends without a cavity, which close off the bubble. The capsule is thus complete.
"Our capsules are constructed so that they take up a single water molecule," says Huc. "They enclose it completely and shield it from surrounding organic solvents." And how does the water molecule get into the capsule? Nuclear magnetic resonance studies support the theory that the helices partially unravel at one end, let the water molecule slip in, and then close again."
The researchers now want to expand their highly promising concept. They are thus working on larger capsules that could take up larger or multiple molecules.
Related stories:
Duke chemists synthesize promising anti-cancer product
Duke University chemists have patented an efficient technique for synthesizing a marine algae extract in sufficient quantities to now test its ability to inhibit the growth of cancerous cells while leaving normal cells unaffected.
Scientists overcome nanotech hurdle
When you make a new material on a nanoscale how can you see what you have made? A team lead by a Biotechnology and Biological Sciences research Council (BBSRC) fellow has made a significant step toward overcoming this major challenge faced by nanotechnology scientists.
Nanojewels made easy
Butterfly wings, peacock feathers, opals and pearls are some of nature's jewels that use nanostructures to dazzle us with color. It's accomplished through the way light reaches our eyes after passing through the submicroscopic mazes within these materials.
Multitasking nanotechnology
Confocal microscope image of a self-assembled monolayer of a polychlorotriphenyl methyl radical patterned on a quartz surface. This multifunctional molecule behaves as an electroactive switch with optical and magnetic response.
A little pressure in proteomics analyses squeezes four hours into a minute
Many coaches inspire better performance by pressuring their teams. Now, proteomics researchers are using pressure to improve the performance of their analyses. In a simple solution to a time-consuming problem, the researchers have found that adding pressure early in their protocol squeezes four hours of waiting into a minute.
First DNA molecule made almost entirely of artificial parts
Chemists in Japan report development of the world's first DNA molecule made almost entirely of artificial parts. The finding could lead to improvements in gene therapy, futuristic nano-sized computers, and other high-tech advances, they say. Their study is scheduled for the July 23 issue of the
Journal of the American Chemical Society.
Wake up and smell the coffee: Study finds that caffeine may help prevent MS
A good cup of coffee might be just the wake-up call scientists need to stop multiple sclerosis.
A New Way to Think About Earth's First Cells
A team of researchers at Harvard University have modeled in the laboratory a primitive cell, or protocell, that is capable of building, copying and containing DNA.