Friday, August 28, 2009

Lots of developments in nanomedicine this week: Scientists have discovered a potential new drug delivery system. They developed a peptide, a small piece of protein that can carry "cargo" for delivery into the cell. The cargo could be a nanoparticle, or even a cell. Riding on the peptide, the cargo gets out of the blood vessel and penetrates the tissue.

New DNA test uses nanotechnology to find early signs of cancer. Based on quantum dots, a new test, which detects both the presence and the quantity of certain DNA changes, could alert people who are at risk of developing the disease and could tell doctors how well a particular cancer treatment is working.

DNA test uses quantum dots to find early signs of cancer


In this illustration, quantum dots are depicted as gold spheres that attract DNA strands linked to cancer risks. When the quantum dots are exposed to certain types of light, they transfer the energy to fluorescent molecules, shown as pink globes, that emit a glow. This enables researchers to detect and count the DNA strands linked to cancer.


In a third nanomedicine-related story, researchers have successfully developed a novel electronic sensor array – called the Nanogap Sensor Array – for more rapid, accurate and cost-efficient testing of DNA for disease diagnosis and biological research.

On to nanoelectronics: Stanford researchers have developed a method of stacking and purifying crystal layers that may pave the way for three-dimensional microchips. The scientists added tiny germanium crystals in the shape of nanowires to a sheet of silicon, and then topped it with a layer of germanium. With heat, the nanowires and the germanium topping took on the crystal structure of the silicon.

A hybrid of silicon nanocircuits and biological components that mimics some of the processes that control the passage of molecules into and out of cells has been created by a team of scientists from UC Davis, Lawrence Livermore National Laboratory and UC Berkeley. The lipid-coated nanocircuits could lead to the development of new classes of bio-sensing tools and biological applications, such as comprehensive blood-chemistry tests that fit on the point of a needle or screening tools for the development of new drugs.

IBM scientists have been able to image the 'anatomy – or chemical structure – inside a molecule with unprecedented resolution, using a complex technique known as noncontact atomic force microscopy. Watch the video:



Solar cells could soon be produced more cheaply using nanoparticle "inks" that allow them to be printed like newspaper or painted onto the sides of buildings or rooftops to absorb electricity-producing sunlight.

Chinese researchers demonstrate that nanofabrication technologies can be advanced by ingenious structure of biofilms. While biofilms are mostly seen from a point of view of pathogenic threats, their complex frameworks with biological behavior, chemical heterogeneity, and physical structure at micro- or even nanoscopic level, could also be useful in nanofabrication – each of these properties can be an attractive avenue for the development of nanotechnology and material science.

And, of course, don't miss Nanowerk's new series: Ten things you sould know about nanotechnology.

Friday, August 21, 2009

Lots of news in the area of nanoelectronics this week. Current lasers can't be made small enough to integrate them into electronic chips. Now researchers have overcome this obstacle, harnessing clouds of electrons called "surface plasmons," instead of the photons that make up light, to create tiny "spasers". This is the first of its kind to emit visible light, representing a critical component for possible future technologies based on nanophotonic circuitry.

Nanochemists have developed nanoscale electric contacts out of organic and inorganic nanowires. In the contact they have crossed the wires like Mikado sticks and coupled several contacts together in an electric circuit. In this way they have produced prototype computer electronics on the nanoscale. This nanowire transistors could become an alternative to silicon for computer chips.

In order to further improve current lithographic chip production technology, researchers are adapting the same methods used in fusion-energy research to create extremely thin plasma beams for a new class of nanolithography required to make future computer chips. The new plasma-based lithography under development generates "extreme ultraviolet" light having a wavelength of 13.5 nanometers, less than one-tenth the size of current lithography.

DNA origami, tiny shapes and patterns self-assembled from DNA, have been heralded as a potential breakthrough for the creation of nanoscale circuits and devices. One roadblock to their use has been that they are made in solution, and they stick randomly to surfaces – like a deck of playing cards thrown onto a floor. Researchers have now demonstrated a way to put DNA origami exactly where they want it on a surface, to line them up like little ducks in a row.

It appears that bacteria can squeeze through practically anything. In extremely small nanoslits they take on a completely new flat shape. Even in this squashed form they continue to grow and divide at normal speeds.

Nanoscale devices capable of measuring the mass of a single biological molecule and the heavier elements have already been developed. Yet, significant advances are still required to reach the ultimate goal of weighing the lightest elements such as hydrogen. By studying gold nanoparticles of highly uniform size and shape, scientists now understand how they lose energy, a key step towards producing nanoscale detectors for weighing any single atom.

In nanomedicine, researchers have used magnetic nanoparticles to guide stem cells to sites of cardiovascular injury in a new method designed to increase the capacity of cells to repair damaged tissue. Following magnetic targeting, there was a five-fold increase in cell localization at a site of vascular injury in rats.

Scary news coming out of China: A study has for the first time claimed a concrete link between exposure to nanoparticles in adhesive paint and development of severe pulmonary fibrosis in a group of young female workers; two of whom went on to suffer fatal lung failure.

And finally, at Nanowerk there is a new series called "Ten things you should know about nanotechnology" – a brief overview of some important aspects and issues, and answers to some of the basic questions on nanotechnologies. Remember how it all started with Feynman's speech?

Friday, August 14, 2009

Researchers at MIT have for the first time shown that carbon nanotubes can grow without a metal catalyst. The researchers demonstrate that zirconium oxide, the same compound found in cubic zirconia "fake diamonds," can also grow nanotubes, but without the unwanted side effects of metal. Another advance on fabricating carbon nanomaterials has been reported by a Northwestern University professor and his students, who have found a new way of turning graphite oxide – a low-cost insulator made by oxidizing graphite powder – into graphene, a hotly studied material that conducts electricity. In this flash reduction process, researchers simply hold a consumer camera flash over the graphite oxide and, a flash later, the material is now a piece of fluffy graphene.

If man-made devices could be combined with biological machines, laptops and other electronic devices could get a boost in operating efficiency. Lawrence Livermore National Laboratory researchers have devised a versatile hybrid platform that uses lipid-coated nanowires to build prototype bionanoelectronic devices.

nanobioelectronic device

An artist's representation of a nanobioelectronic device incorporating alamethycin biological pore. In the core of the device is a silicon nanowire (grey), covered with a lipid bilayer (blue). The bilayer incorporates bundles of alamethicin molecules (purple) that form pore channels in the membrane. Transport of protons though these pore channels changes the current through the nanowire. (Image: Scott Dougherty, LLNL)


When bees sting, they pump poison into their victims. Now the toxin in bee venom has been harnessed to kill tumor cells by researchers at Washington University School of Medicine in St. Louis. The researchers attached the major component of bee venom to nano-sized spheres that they call nanobees.

In other news in cancer-fighting nanomedicine, researchers at Wake Forest University have increased the tumor-killing power of carbon nanotubes by encasing them in DNA. The DNA-encasement of the tubes actually increased the amount of heat produced upon irradiation of the nanotubes with near-infrared light and appears to be a promising new tool for hyperthermia applications.

Growing – and precisely aligning – spear-shaped zinc oxide crystals with a diameter of 100-200 nm on a surface of single-crystal silicon, researchers at Missouri University of Science and Technology may have developed a method to make more efficient solar cells. By growing zinc oxide on top of the silicon, you're putting two semiconductors on top of each other, thereby widening the spectrum from which a solar cell could draw light.

Friday, August 7, 2009

The engineers‘ dream of self-healing surfaces has taken another step towards becoming reality – researchers have produced a electroplated layer that contains tiny nanometer-sized capsules. If the layer is damaged, the capsules release fluid and repair the scratch.

The world's smallest computers, made of DNA and other biological molecules, just got more "user friendly" thanks to research at the Weizmann Institute of Science.

The world's smallest electric motor runs on only two atoms. The principle is easy: one starter and one motor atom in a ring of laser light - and a bit of fine tuning, in order to move always into the right direction.

Researchers at the University of Washington report progress in mapping brain tumors: theyhave been able to illuminate brain tumors by injecting fluorescent nanoparticles into the bloodstream that safely cross the blood-brain barrier – an almost impenetrable barrier that protects the brain from infection. The nanoparticles remained in mouse tumors for up to five days and did not show any evidence of damaging the blood-brain barrier.

Neurons communicate with each other with the help of nano-sized vesicles. Disruption of this communication process is responsible for many diseases and mental disorders like e.g. depression. Nerve signals travel from one neuron to another through vesicles - a nano-sized container loaded with neurotransmitter molecules. A vesicle fuses with the membrane surrounding a neuron, releases neurotransmitters into the surroundings that are detected by the next neuron in line. Researchers can now make "live recordings" of cell communication by quantifying contact areas formed between vesicles and determine the vesicle size and shape with nano-scale resolution.

evolutionary tree for nanoparticles


Researchers determine shape and size of the contact area between vesicle and membrane by measuring colour intensity from flourescent molecules. Right: Vesicle marked by acceptor flourescent molecules that light up when close to donor molecules (left). Middle: A plot of the same, calculated FRET.


The veil is being lifted from the once unseen world of molecular activity. Not so long ago only the final products were visible and scientists were forced to gauge the processes behind those products by ensemble averages of many molecules. The limitations of that approach have become clear with the advent of technologies that allow for the observation and manipulation of single molecules. A prime example is the recent first ever direct observations in real-time of the growth of single nanocrystals in solution, which revealed that much of what we thought we knew is wrong.

Scientists at the Technische Universitaet Muenchen and Harvard University have thrown the lid off a new toolbox for building nanoscale structures out of DNA, with complex twisting and curving shapes. They report a series of experiments in which they folded DNA, origami-like, into three-dimensional objects including a beach ball-shaped wireframe capsule just 50 nanometers in diameter. The result is a variety of nanoscale structures folded, origami-like, from DNA:

evolutionary tree for nanoparticles