Friday, July 30, 2010

This week in nanotechnology - July 30, 2010

Spotting a single cancerous cell that has broken free from a tumor and is traveling through the bloodstream to colonize a new organ might seem like finding a needle in a haystack. But a new imaging technique from the University of Washington is a first step toward making this possible. Researchers have developed a multifunctional nanoparticle that eliminates the background noise, enabling a more precise form of medical imaging – essentially erasing the haystack, so the needle shines through.

Imagine a device the size of – and nearly as cheap as – a grain of sand which is capable of analyzing the environment around it, recognize its chemical composition, and report it to a monitoring system. Researchers have now demonstrated a method to design prospective simple sensing arrays - so-called electronic noses - which, in principle, might be scaled down to the size of few micrometers and thus become the smallest analytical instrument.

First step towards electronic DNA sequencing: Translocation through graphene nanopores. Researchers at the University of Pennsylvania have developed a new, carbon-based nanoscale platform to electrically detect single DNA molecules. Using electric fields, the tiny DNA strands are pushed through nanoscale-sized, atomically thin pores in a graphene nanopore platform that ultimately may be important for fast electronic sequencing of the four chemical bases of DNA based on their unique electrical signature.

atomically-thin graphene nanopores

Electric fields push tiny DNA strands through atomically-thin graphene nanopores that ultimately may sequence DNA bases by their unique electrical signature.

By linking individual semiconductor quantum dots with gold nanoparticles, scientists have demonstrated the ability to enhance the intensity of light emitted by individual quantum dots by up to 20 times. The precision method for making the light-emitting particle clusters will greatly advance scientists' ability to study and modify the optical properties of quantum dots, and could eventually lead to improved solar energy conversion devices, light-controlled electronics, and biosensors.

Using chemical "nanoblasts" that punch tiny holes in the protective membranes of cells, researchers have demonstrated a new technique for getting therapeutic small molecules, proteins and DNA directly into living cells.

Numerous pathogens can cause bloodstream infections (sepsis) and the most straightforward cure is to remove the disease-causing factors from a patient's blood as quickly as possible. By using metal nanomagnets carrying target-specific ligands, researchers at ETH Zurich have shown that blood purification at a nano- to pico-molar scale is possible.

Researchers report the creation of pseudo-magnetic fields far stronger than the strongest magnetic fields ever sustained in a laboratory – just by putting the right kind of strain onto a patch of graphene. They show that when graphene is stretched to form nanobubbles on a platinum substrate, electrons behave as if they were subject to magnetic fields in excess of 300 tesla, even though no magnetic field has actually been applied.

 graphene nanobubble

In this scanning tunneling microscopy image of a graphene nanobubble, the hexagonal two-dimensional graphene crystal is seen distorted and stretched along three main axes.

Friday, July 23, 2010

This week in nanotechnology - July 23, 2010

Nanotechnologists at University of Twente's MESA+ research institute have developed a sensor that can detect anthrax spores. The invention is more sensitive and efficient than existing detection methods. The sensor that can detect a biomarker of the spores and thus determine their presence in a concentration one thousand times lower than the known toxic level.

Gene-silencing nanoparticles may put end to mosquito pest. Research conducted by a Kansas State University team may help solve a problem that scientists and pest controllers have been itching to for years. The team investigated using nanoparticles to deliver double-stranded ribonucleic acid, dsRNA – a molecule capable of specifically triggering gene silencing – into mosquito larvae through their food. By silencing particular genes, the dsRNA may kill the developing mosquitoes or make them more susceptible to pesticides.

A new vaccine-delivery patch based on hundreds of microscopic needles that dissolve into the skin could allow persons without medical training to painlessly administer vaccines -- while providing improved immunization against diseases such as influenza. Patches containing micron-scale needles that carry vaccine with them as they dissolve into the skin could simplify immunization programs by eliminating the use of hypodermic needles – and their "sharps" disposal and re-use concerns. Applied easily to the skin, the microneedle patches could allow self-administration of vaccine during pandemics and simplify large-scale immunization programs in developing nations.

vaccine-delivery patch

By imaging the cell walls of a zinnia leaf down to the nanometer scale, energy researchers have a better idea about how to turn plants into biofuels. Using different microscopy methods, the team was able to visualize single cells in detail, cellular substructures, fine-scale organization of the cell wall, and even chemical composition of single zinnia cells, indicating that they contain an abundance of lignocellulose.

To trap and hold tiny microparticles, engineers at Harvard have "put a ring on it," using a silicon-based circular resonator to confine particles stably for up to several minutes. The advance could one day lead to the ability to direct, deliver, and store nanoparticles and biomolecules on all-optical chips.

Scientists at the University of Liverpool have constructed molecular 'knots' with dimensions of around two nanometer. Most molecules are held together by chemical bonds between atoms – 'nano-knots' are instead mechanically bonded by interpenetrating loops. This is an unusual example of 'self-assembly', a process which underpins biology and allows complex structures to assemble from more simple building blocks.

The molecular knots have dimensions of around two nanometers

ETH Zurich researchers have built a transistor whose crucial element is a carbon nanotube, suspended between two contacts, with outstanding electronic properties. A novel fabrication approach allowed the scientists to construct a transistor with no gate hysteresis. This opens up new ways to manufacture nano-sensors and components that consume particularly little energy.

Engineers at Oregon State University have made a significant advance toward producing electricity from sewage, by the use of new coatings on the anodes of microbial electrochemical cells that increased the electricity production about 20 times. The findings bring the researchers one step closer to technology that could clean biowaste at the same time it produces useful levels of electricity – a promising new innovation in wastewater treatment and renewable energy.

Astronomers using NASA's Spitzer Space Telescope have discovered carbon molecules, known as "buckyballs," in space for the first time. The fukkerenes were found in a planetary nebula named Tc 1. Planetary nebulas are the remains of stars, like the sun, that shed their outer layers of gas and dust as they age. A compact, hot star, or white dwarf, at the center of the nebula illuminates and heats these clouds of material that has been shed. The buckyballs were found in these clouds, perhaps reflecting a short stage in the star's life, when it sloughs off a puff of material rich in carbon.

Friday, July 16, 2010

This week in nanotechnology - July 16, 2010

Nanotechnology wound dressing automatically detects and treats infection. Researchers in the UK have conducted experiments that explored the elementary question of what it is that makes some bacteria pathogenic, and some not? Based on their findings, they have demonstrated that a simple vesicle (nanocapsule) system can be used as a 'nano-Trojan horse' for controlling bacterial growth and infection. Integrated into wound dressings, this novel material can automatically detect infection by pathogenic bacteria and respond to this by releasing an antibiotic into the wound, and changing color to alert medical staff.

A team of researchers from Delft University of Technology announces a new type of nanopore device that may significantly impact the way we screen DNA molecules, for example to read off their sequence. They report a novel technique to fabricate tiny holes in a layer of graphene (a carbon layer with a thickness of only 1 atom) and they managed to detect the motion of individual DNA molecules that travel through such a hole.

Adding a bit of graphene to battery materials could dramatically cut the time it takes to recharge electronics. Researchers at the Department of Energy's Pacific Northwest National Laboratory have demonstrated that small quantities of graphene — an ultra-thin sheet of carbon atoms — can dramatically improve the power and cycling stability of lithium-ion batteries, while maintaining high energy storage capacity. The pioneering work could lead to the development of batteries that store larger amounts of energy and recharge quickly.

New solar-powered process removes CO2 from the air and stores it as solid carbon. Researchers have now presented the first experimental evidence of a new solar conversion process, combining electronic and chemical pathways, for carbon dioxide capture in what could become a revolutionary approach to remove and recycle CO2 from the atmosphere on a large scale. Rather than trying to sequester or hide away excess carbon dioxide, this new method allows it to be stored as solid carbon or converted in useful products ranging from plastics to synthetic jet fuel.

Rice University scientists have found the "ultimate" solvent for all kinds of carbon nanotubes, a breakthrough that brings the creation of a highly conductive quantum nanowire ever closer. Nanotubes have the frustrating habit of bundling, making them less useful than when they're separated in a solution. The researchers have found that chlorosulfonic acid can dissolve half-millimeter-long nanotubes in solution, a critical step in spinning fibers from ultralong nanotubes.

New research confirms that a revolutionary technology developed at Wake Forest University will slash years off the time it takes to develop drugs – bringing vital new treatments to patients much more quickly. Lab-on-Bead uses nanoscopic beads studded with "pins" that match a drug to a disease marker in a single step, so researchers can test an infinite number of possibilities for treatments all at once. When Lab-on-Bead makes a match, it has found a viable treatment for a specific disease – speeding up drug discovery by as much as 10,000 times and cutting out years of testing and re-testing in the laboratory.

Friday, July 9, 2010

This week in nanotechnology - July 9, 2010

Clusters of heated, magnetic nanoparticles targeted to cell membranes can remotely control ion channels, neurons and even animal behavior. The UB researchers demonstrated that their method could open calcium ion channels, activate neurons in cell culture and even manipulate the movements of the tiny nematode, C. elegans.

While those wonderful light sabers in the Star Wars films remain the figment of George Lucas' fertile imagination, light mills – rotary motors driven by light – that can power objects thousands of times greater in size are now fact. Researchers have created the first nano-sized light mill motor whose rotational speed and direction can be controlled by tuning the frequency of the incident light waves.

Researchers have demonstrated how they can adjust process conditions to influence the properties of novel plasma polymer coatings containing silver nanoparticles. Tailor-made films can be generated through a one-step plasma process. The scientists developed these new coatings, which kill bacteria while having no negative effect on human tissue.

At first, nanoshocks may seem like something to describe the millions of aftershocks of a large earthquake. But physicists are using an ultra-fast laser-based technique they dubbed "nanoshocks" for something entirely different. In fact, the "nanoshocks" have such a small spatial scale that scientists can use them to study shock behavior in tiny samples such as thin films or other systems with microscopic dimensions (a few tens of micrometers). In particular they have used the technique to shock materials under high static pressure in a diamond anvil cell.

Researchers are using nanotechnology to develop a medical dressing which will detect and treat infection in wounds. The dressing will work by releasing antibiotics from nanocapsules triggered by the presence of disease-causing pathogenic bacteria, which will target treatment before the infection takes hold. The dressing will also change colour when the antibiotic is released, alerting healthcare professionals that there is infection in the wound.

The tunable fluorescent nanoparticles known as quantum dots make ideal tools for distinguishing and identifying rare cancer cells in tissue biopsies. New research describes how multicolor quantum dots linked to antibodies can distinguish the Reed-Sternberg cells that are characteristic of Hodgkin's lymphoma.

Reed-Sternberg cells

Reed-Sternberg cells can be distinguished by their red outline, blue and white internal staining, and their lack of green staining

Metallic carbon nanotubes show great promise for applications from microelectronics to power lines because of their ballistic transmission of electrons. But who knew magnets could stop those electrons in their tracks? Researchers came to the unexpected conclusion that magnetic fields can turn highly conductive nanotubes into semiconductors.

Biomechanical energy is one of the main energy components in biological systems. Developing an effective technique that can convert biomechanical energy into electricity is important for the future of in vivo implantable biosensors and other nanomedical devices. Researchers have already shown the conversion of biomechanical energy into electricity by a muscle-movement-driven nanogenerator to harvest mechanical energy from body movement under in vitro conditions. In a first demonstration of using nanotechnology to convert tiny physical motion into electricity in an in vivo environment, the same team has now reported the implanting of a nanogenerator in a live rat to harvest energy generated by its breath and heartbeat.

Friday, July 2, 2010

This week in nanotechnology - July 2, 2010

When it comes to metal catalysts, the platinum standard is, well, platinum! However, at about $2,000 an ounce, platinum is more expensive than gold. The high cost of the raw material presents major challenges for the future wide scale use of platinum in fuel cells. Research at the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) suggests that one possible way to meet these challenges is to think small – really small.

Molecules typically found in blue jean and ink dyes may lead to more efficient solar cells: Cornell University researchers have discovered a simple process for building an organic framework that could lead to economical, flexible and versatile solar cells.

Scientific results from the world's most powerful hard X-ray laser show its unique ability to control the behaviors of individual electrons within simple atoms and molecules by stripping them away, one by one—in some cases creating hollow atoms. These results describe in great detail how the Linac Coherent Light Source's intense pulses of X-ray light change the very atoms and molecules they are designed to image. Controlling those changes will be critical to achieving the atomic-scale images of biological molecules and movies of chemical processes that the LCLS is designed to produce.

Using a unique hybrid nanostructure, University of Maryland researchers have shown a new type of light-matter interaction and also demonstrated the first full quantum control of qubit spin within very tiny colloidal nanostructures (a few nanometers), thus taking a key step forward in efforts to create a quantum computer.

Irregular pores, low flow rates: The plastic membrane filters used in sterile filtration do not always ensure that conditions are really sterile. Filter membranes of aluminum oxide are more reliable – the size of the nanopores can be determined with precision. Even the smallest viruses cannot pass through the membrane.

Since its discovery, graphene—an unusual and versatile substance composed of a single-layer crystal lattice of carbon atoms—has caused much excitement in the scientific community. Now, Nongjian Tao, a researcher at the Biodesign Institute at Arizona State University has hit on a new way of making graphene.

Carbon nanotubes turn glass fibers into multifunctional sensors. Researchers in Germany have now demonstrated a simple approach to deposit multiwalled carbon nanotube (MWCNT) networks onto glass fiber surfaces, thereby achieving semiconductive MWCNT–glass fibers.

And finally something fun for the weekend: Here is another installment of our collection of amazing images from nanotechnology labs from all over the world.

Nano PacMan

Nano PacMan made of copper oxide Scanning electron microscope image of a copper oxide cluster, 3.5 microns in diameter, prepared by evaporation and condensation over an alumina substrate. The smiley nose and eye are present in the original SEM image, which has only been color-enhanced. (Image: Elisabetta Comini, University of Brescia, Italy)