Friday, April 29, 2011

This week in nanotechnology - April 29, 2011

Scientists have created a single-electron transistor that provides a building block for new, more powerful computer memories, advanced electronic materials, and the basic components of quantum computers. The transistor's central component – an island only 1.5 nanometers in diameter – operates with the addition of only one or two electrons. That capability would make the transistor important to a range of computational applications, from ultradense memories to quantum processors, powerful devices that promise to solve problems so complex that all of the world's computers working together for billions of years could not crack them.

Nanotechnology paper is stronger than steel: Graphene paper is a material that can be processed, reshaped and reformed from its original raw material state - graphite. Compared to steel, the prepared graphene paper is six times lighter, five to six times lower density, two times harder with 10 times higher tensile strength and 13 times higher bending rigidity.

Researchers inject nanofiber spheres carrying cells into wounds to grow tissue: for the first time, scientists have made star-shaped, biodegradable polymers that can self-assemble into hollow, nanofiber spheres, and when the spheres are injected with cells into wounds, these spheres biodegrade, but the cells live on to form new tissue.
Nanofibrous hollow microspheres
Nanofibrous hollow microspheres

With its promise of superfast computers and ultrapowerful optical microscopes among the many possibilities, plasmonics has become one of the hottest fields in high-technology. However, to date plasmonic properties have been limited to nanostructures that feature interfaces between noble metals and dielectrics. Now, researchers with the Berkeley Lab have shown that plasmonic properties can also be achieved in the semiconductor nanocrystals known as quantum dots. This discovery should make the field of plasmonics even hotter.

Boosting medicine with nanotechnology strengthens drug cocktail many times over. Researchers describe silica nanoparticles about 150 nanometers in diameter as honeycombed with cavities that can store large amounts and varieties of drugs. The enormous capacity of the nanoporous core, with its high surface area, combined with the improved targeting of an encapsulating lipid bilayer, permit a single 'protocell' loaded with a drug cocktail to kill a drug-resistant cancer cell.

Researchers at MIT have found a way to make significant improvements to the power-conversion efficiency of solar cells by enlisting the services of tiny viruses to perform detailed assembly work at the microscopic level. Researchers found that a genetically engineered version of a virus called M13, which normally infects bacteria, can be used to control the arrangement of carbon nanotubes on a surface, keeping the tubes separate so they can't short out the circuits, and keeping the tubes apart so they don't clump.

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.

Friday, April 8, 2011

This week in nanotechnology - April 8, 2011

'Good cholesterol' nanoparticles seek and destroy cancer cells: Synthetic HDL nanoparticles loaded with small interfering RNA to silence cancer-promoting genes selectively shrunk or destroyed ovarian cancer tumors in mice, a research team led by scientists from The University of Texas MD Anderson Cancer Center and the University of North Texas Health Science Center reports.

Nanoparticles could offer big hope in a small package to the many millions of people who are allergic to the nickel in everything from jewelry to coins and cell phones, say scientists at Brigham and Women's Hospital. The scientists believe that nanoparticles containing calcium added to a cream or coated on a nickel-containing object could prevent the itchy redness associated with an allergy to the nickel found in everyday objects like rings.

With the first observation of thermoelectric effects at graphene contacts, University of Illinois researchers found that graphene transistors have a nanoscale cooling effect that reduces their temperature. Future computer chips made out of graphene – carbon sheets 1 atom thick – could be faster than silicon chips and operate at lower power.
An atomic force microscope tip scans the surface of a graphene-metal contact to measure temperature with spatial resolution of about 10 nm
An atomic force microscope tip scans the surface of a graphene-metal contact to measure temperature with spatial resolution of about 10 nm and temperature resolution of about 250 mK. Color represents temperature data.

Scientists at the Institute of Bioengineering and Nanotechnology (IBN) and IBM Research have developed the first biodegradable polymer nanoparticles to combat drug-resistant superbugs, such as Methicillin-Resistant Staphylococcus aureus (MRSA). These nanoparticles can selectively kill the bacteria without destroying healthy red blood cells, and being biodegradable, have great potential to treat infectious diseases in the body.

Using an advanced form of a rubber stamp, researchers have developed a way to adhere an ultra-thin antibacterial coating to a wound. The researchers describe a process for creating a transparent ultra-thin polymer coating carrying precise loads of extremely fine silver nanoparticles.

For the first time, the quantum behaviour of molecules consisting of more than 400 atoms was demonstrated by quantum physicists. The team sets a new record in the verification of the quantum properties of nanoparticles. In addition, an important aspect of the famous thought experiment known as 'Schroedinger's cat' is probed. However, due to the particular shape of the chosen molecules the reported experiment could be more fittingly called 'molecular octopus'.

Friday, April 1, 2011

This week in nanotechnology - April 1, 2011

How would you like to store all the films ever made on a device the size of an I-phone? Magnets made of just a few metallic atoms could make it possible to build radically smaller storage devices and have also recently been proposed as components for spintronics devices. There's just one obstacle on the way. Nano-sized magnets have only been seen to work at temperatures a few hairs above absolute zero. Now a chemistry student at the University of Copenhagen has demonstrated that molecular magnets using the metals ruthenium and osmium retain their magnetic properties at higher temperatures.

Scientists at Berkeley Lab's Molecular Foundry have pioneered a new chemical mapping method that provides unprecedented insight into materials at the nanoscale. Moving beyond traditional static imaging techniques, which provide a snapshot in time, these new maps will guide researchers in deciphering molecular chemistry and interactions at the nanoscale—critical for artificial photosynthesis, biofuels production and light-harvesting applications such as solar cells. This new technique allows the capture of very high-resolution images of nanomaterials with a huge amount of physical and chemical information at each pixel.
coaxial probe for imaging a carbon nanotube
Schematic of coaxial probe for imaging a carbon nanotube (left) and chemical map of carbon nanotube with chemical and topographical information at each pixel (right).

A Harvard bioengineer and an MIT aeronautical engineer have created a new device that can detect single cancer cells in a blood sample, potentially allowing doctors to quickly determine whether cancer has spread from its original site. The carbon nanotube-based microfluidic device is about the size of a dime, and could also detect viruses such as HIV. It could eventually be developed into low-cost tests for doctors to use in developing countries where expensive diagnostic equipment is hard to come by.

Stanford researchers have developed a battery that takes advantage of the difference in salinity between freshwater and seawater to produce electricity. As an indicator of the battery's potential for producing power, the research team calculated that if all the world's rivers were put to use, their batteries could supply about 2 terawatts of electricity annually – that's roughly 13 percent of the world's current energy consumption.

Researchers from North Carolina State University have investigated the viability of a technique called "spincasting" for creating thin films of nanoparticles on an underlying substrate – an important step in the creation of materials with a variety of uses, from optics to electronics. Spincasting, which utilizes centrifugal force to distribute a liquid onto a solid substrate, already has a variety of uses. For example, it is used in the electronics industry to deposit organic thin films on silicon wafers to create transistors.