Friday, January 14, 2011

This week in nanotechnology - January 14, 2011

A team of scientists has created very soft hydrogel particles that closely mirror some of the key properties of red blood cells, potentially helping pave the way for the development of synthetic blood. Tests of the particles' ability to perform functions such as transporting oxygen or carrying therapeutic drugs have not been conducted, and they do not remain in the cardiovascular system as long as real red blood cells.

New research shows how light can be used to control the electrical properties of graphene, paving the way for graphene-based optoelectronic devices and highly sensitive sensors.

A few unassuming drops of liquid locked in a very precise game of "follow the leader" could one day be found in mobile phone cameras, medical imaging equipment, implantable drug delivery devices, and even implantable eye lenses. Engineering researchers have developed liquid pistons, in which oscillating droplets of ferrofluid precisely displace a surrounding liquid. The pulsating motion of the ferrofluid droplets, which are saturated with metal nanoparticles, can be used to pump small volumes of liquid. The study also demonstrated how droplets can function as liquid lenses that constantly move, bringing objects into and out of focus.

European researchers report direct observation of carbon monoxide binding. Carbon monoxide is highly toxic since it blocks the binding site for oxygen in hemoglobin. This very principle – a porphyrin ring with a central iron or cobalt atom that the poisonous gas attaches to – can be used to implement sensors to warn against carbon monoxide. Physicists have now deciphered the mechanism for binding of gas molecules to iron and cobalt porphyrins.

A scanning tunneling microscopy image (left) shows four porphyrins. The models (right) illustrate the two systems shown in the picture. The protrusions correspond to the central atom (yellow sphere) and the two elevated portions to the saddle (orange). The characteristic cross shape results from the attached carbon monoxide molecules (red and blue).

Many futurists envision a world in which polymer membranes with molecular-sized channels are used to capture carbon, produce solar-based fuels, or desalinate sea water, among many other functions. This will require methods by which such membranes can be readily fabricated in bulk quantities. A technique representing a significant first step down that road has now been successfully demonstrated.

Researchers have created the first coils of silicon nanowire on a substrate that can be stretched to more than double their original length, moving us closer to incorporating stretchable electronic devices into clothing, implantable health-monitoring devices, and a host of other applications.

Fastest movie in the world recorded - a method to film nanostructures. Processes at a molecular level are not only miniscule, they are often extremely fast, and therefore difficult to capture in action. Scientists now present a method that takes us a good step towards producing a "molecular movie". They can record two pictures at such a short time interval that it will soon be possible to observe molecules and nanostructures in real time.

Researchers have demonstrated bio-inspired structures that self-assemble from simple building blocks: spheres. The helical "supermolecules" are made of tiny colloid balls instead of atoms or molecules. Similar methods could be used to make new materials with the functionality of complex colloidal molecules.