Saturday, April 16, 2011

This week in nanotechnology - April 15, 2011

Are we only a hop, skip and jump away from controlled molecular motion? We may very well be, according to researchers. Controlling how molecules move on surfaces could be the key to more potent drugs that block the attachment of viruses to cells, and will also speed development of new materials for electronics and energy applications.

Researchers at the University of Sheffield have discovered a new way of making small molecules self-assemble into complex nanopatterns, which will push the limits of what is possible in "bottom-up" methods of nanopatterning for advanced functional materials through molecular self-assembly. The study opens the way to new methods of producing `bottom-up´ ultra-small electronic and photonic integrated circuits. This would mean that instead of the expensive and slow electron, ion-beam or X-ray lithography, the molecules would assemble and form the desired patterns themselves.

Creating artificial structures from DNA is the objective of DNA nanotechnology. This new discipline, which combines biology, physics, chemistry and material science makes use of the ability of the natural DNA-strains' capacity for self assembly. Smileys or small boxes, measuring only 10s of nanometers were created from DNA in a drop of water. As part of the experiments, researchers were able to create two rings of DNA only 18 nanometers in size, and to interlock them like two links in a chain.
The world's smallest wedding rings are built up by two interlocked DNA-strands
The world's smallest wedding rings are built up by two interlocked DNA-strands.

When a drop falls on a lotus flower it remains on the surface without wetting it. This is due, firstly, to the chemical components of the leaves of this plant, which are hydrophobic and therefore repel water, and, secondly, to the nanostructure of the surface, which augments the repellent effect. Taking these nanostructural properties as a starting point, researchers have carried out a study in which they demonstrate the physical conditions required for the controlled production of drops between the micro- and nanoscales.

Water and oil may not mix, but, like two boxers nearing the end of the final round, they can get awfully tangled up. Now, scientists have created a filter that separates the two substances as quickly and cleanly as a ref breaking up a clinch. Their fine, stainless steel mesh is coated with carbon nanotubes about 10 microns across. They have a super-honeycomb structure that repels water,but they like organic stuff, like oil.
A scanning electron microscopy image of the carbon nanotube-coated filter
A scanning electron microscopy image of the carbon nanotube-coated filter. For comparison, the inset is bare stainless steel mesh.

Researchers advance toward hybrid spintronic computer chips. A team have created the first electronic circuit to merge traditional inorganic semiconductors with organic "spintronics" – devices that utilize the spin of electrons to read, write and manipulate data.