Amazing Science
Find tag "nanotech"
499.6K views | +181 today
Amazing Science
Amazing science facts - 3D_printing • aging • AI • anthropology • art • astronomy • bigdata • bioinformatics • biology • biotech • chemistry • computers • cosmology • education • environment • evolution • future • genetics • genomics • geosciences • green_energy • history • language • map • material_science • math • med • medicine • microscopy • nanotech • neuroscience • paleontology • photography • photonics • physics • postings • robotics • science • technology • video
Your new post is loading...
Scooped by Dr. Stefan Gruenwald!

Shaky sensor: a cantilever covered with bacteria shakes up and down as bacteria metabolize on its surface

Shaky sensor: a cantilever covered with bacteria shakes up and down as bacteria metabolize on its surface | Amazing Science |

A patient admitted to a hospital with a serious bacterial infection may have only a few hours to live. Figuring out which antibiotic to administer, however, can take days. Doctors must grow the microbes in the presence of the drugs and see whether they reproduce. Rush the process, and they risk prescribing ineffective antibiotics, exposing the patient to unnecessary side effects, and spreading antibiotic resistance. Now, researchers have developed a microscopic "tuning fork" that detects tiny vibrations in bacteria. The device might one day allow physicians to tell the difference between live and dead microbes—and enable them to recognize effective and ineffective antibiotics within minutes.


"It's a brilliant method," provided subsequent investigations confirm the researchers' interpretation of their data, says Martin Hegner, a biophysicist at Trinity College Dublin who was not involved in the work.


The research involves tiny, flexible bars called cantilevers that vibrate up and down like the prongs of a tuning fork when they receive an input of energy. Cantilevers are an important part of atomic force microscopy, which is useful for making atomic scale resolutions of surfaces for use in nanotechnology or atomic physics research. In this technique, a minute needle attached to a cantilever moves across a surface, and the deflection of the cantilever gives information about how atoms are arranged on the surface. It can even be used to shunt atoms around. More recently, however, they have been used without the needle as tiny oscillators, allowing scientists to investigate matter directly attached to the cantilever.


Biophysicist Giovanni Longo and colleagues at the Swiss Federal Institute of Technology in Lausanne and the University of Lausanne in Switzerland immersed these cantilevers in a liquid bacterial growth medium and monitored their movement using a laser. They found that the bare cantilever moved very slightly as a result of the thermal movement of the liquid molecules in the medium. They then covered both sides of the cantilever with Escherichia coli bacteria, which can cause food poisoning, and immediately found that the oscillations became much more pronounced. The researchers believe that chemical processes that occur inside the bacteria as they metabolize energy are driving the oscillation. "What we see is that if you have some sort of a moving system on the cantilever, you are going to induce a movement on the cantilever itself," Longo explains. "Exactly what kind of metabolic movement we see is something that we are still studying."


To determine if the cantilevers could detect the impact of drugs, the team added ampicillin, an antibiotic that the cultured bacteria were sensitive to. 


The size of the cantilever's oscillations decreased almost 20-fold within 5 minutes, the researchers report. Fifteen minutes later, the scientists flushed the antibiotic out with fresh growth medium, but the movement of the cantilever did not increase again. This, the researchers say, suggests that the antibiotic had killed the bacteria. When they used an ampicillin-resistant strain of E. coli, however, they found that the oscillations initially decreased but returned to normal within about 15 minutes, indicating that the microbes had recovered.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

New system of 2D structures to guide plasmonic waves at ultrashort wavelength for improved information processing

New system of 2D structures to guide plasmonic waves at ultrashort wavelength for improved information processing | Amazing Science |

Researchers at MIT have proposed a new system that combines ferroelectric materials — the kind often used for data storage — with graphene, a two-dimensional form of carbon known for its exceptional electronic and mechanical properties. The resulting hybrid technology could eventually lead to computer and data-storage chips that pack more components in a given area and are faster and less power-hungry.

The new system works by controlling waves called surface plasmons. These waves are oscillations of electrons confined at interfaces between materials; in the new system the waves operate at terahertz frequencies. Such frequencies lie between those of far-infrared light and microwave radio transmissions, and are considered ideal for next-generation computing devices.

The team’s new system allows waves to be concentrated at much smaller length scales, which could lead to a tenfold gain in the density of components that could be placed in a given area of a chip, Fang says. 

The team’s initial proof-of-concept device uses a small piece of graphene sandwiched between two layers of the ferroelectric material to make simple, switchable plasmonic waveguides. This work used lithium niobate, but many other such materials could be used, the researchers say. 

Light can be confined in these waveguides down to one part in a few hundreds of the free-space wavelength, Jin says, which represents an order-of-magnitude improvement over any comparable waveguide system. “This opens up exciting areas for transmitting and processing optical signals,” he says.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

First 3D printed battery that is the size of a grain of sand and comparable to current commercial batteries

First 3D printed battery that is the size of a grain of sand and comparable to current commercial batteries | Amazing Science |

A research team from Harvard University and the University of Illinois at Urbana-Champaign has demonstrated the ability to 3D print a battery. 3D printing can now be used to print lithium-ion microbatteries the size of a grain of sand. The printed microbatteries could supply electricity to tiny devices in fields from medicine to communications, including many that have lingered on lab benches for lack of a battery small enough to fit the device, yet provide enough stored energy to power them. Novel application of 3D printing could enable the development of miniaturized medical implants, compact electronics, tiny robots, and more.


To make the microbatteries, a team based at Harvard University and the University of Illinois at Urbana-Champaign printed precisely interlaced stacks of tiny battery electrodes, each less than the width of a human hair.

“Not only did we demonstrate for the first time that we can 3D-print a battery; we demonstrated it in the most rigorous way,” said Jennifer A. Lewis, senior author of the study, who is also the Hansjörg Wyss Professor of Biologically Inspired Engineering at the Harvard School of Engineering and Applied Sciences (SEAS), and a Core Faculty Member of the Wyss Institute for Biologically Inspired Engineering at Harvard University. Lewis led the project in her prior position at the University of Illinois at Urbana-Champaign, in collaboration with co-author Shen Dillon, an Assistant Professor of Materials Science and Engineering there.


The scientists realized they could pack more energy if they could create stacks of tightly interlaced, ultrathin electrodes that were built out of plane. For this they turned to 3D printing. 3D printers follow instructions from three-dimensional computer drawings, depositing successive layers of material—inks—to build a physical object from the ground up, much like stacking a deck of cards one at a time. The technique is used in a range of fields, from producing crowns in dental labs to rapid prototyping of aerospace, automotive, and consumer goods. Lewis’ group has greatly expanded the capabilities of 3D printing. They have designed a broad range of functional inks—inks with useful chemical and electrical properties. And they have used those inks with their custom-built 3D printers to create precise structures with the electronic, optical, mechanical, or biologically relevant properties they want.

Vloasis's curator insight, June 19, 2013 7:05 PM

The implication of batteries so small that they cannot be seen definitely has a god-factor ring to it.

Scooped by Dr. Stefan Gruenwald!

Graphene can be made magnetic and effect can be switched on and off, opening avenue to graphene electronics

Graphene can be made magnetic and effect can be switched on and off, opening avenue to graphene electronics | Amazing Science |

In a report published in Nature Communications, a University of Manchester team led by Dr Irina Grigorieva shows how to create elementary magnetic moments in graphene and then switch them on and off. 

This is the first time magnetism itself has been toggled, rather than the magnetization direction being reversed. Modern society is unimaginable without the use of magnetic materials. They have become an integral part of electronic gadgets where devices including hard disks, memory chips and sensors employ miniature magnetic components. Each micro-magnet allows a bit of information (‘0’ or ‘1’) to be stored as two magnetization directions (‘north’ and ‘south’). This area of electronics is called spintronics. 

Despite huge advances, a big disappointment of spintronics has so far been its inability to deliver active devices, in which switching between the north and south directions is done in a manner similar to that used in modern transistors. This situation may dramatically change due to the latest discovery. 
Graphene is a chicken wire made of carbon atoms. It is possible to remove some of these atoms which results in microscopic holes called vacancies. The Manchester scientists have shown that electrons condense around these holes into small electronic clouds, and each of them behaves like a microscopic magnet carrying one unit of magnetism, spin. 

Dr Grigorieva and her team have shown that the magnetic clouds can be controllably dissipated and then condensed back. 

She explains: “This breakthrough allows us to work towards transistor-like devices in which information is written down by switching graphene between its magnetic and non-magnetic states. These states can be read out either in the conventional manner by pushing an electric current through or, even better, by using a spin flow. Such transistors have been a holy grail of spintronics.”

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Reversible Male Contraception With Gold Nanorods

Reversible Male Contraception With Gold Nanorods | Amazing Science |

Gold nanorods injected into mice testes heat up when excited by a near-infrared laser, killing sperm cells and damaging sperm-generating cells. Stained cross-sections of testis tissue show the damage seven days after the treatment (right). As a comparison, tubules in a testis injected with saline solution remains intact, with sperm and sperm-generating cells filling the middle of the tubules (left). An average tubule is 200 µm wide.

Sun, Jun Wang, and their colleagues developed the new method based on the long-known fact that heating testis tissue kills sperm cells. To do the heating, they turned to rod-shaped gold nanoparticles, which absorb infrared light and convert it into heat. Other researchers are developing ways to use these particles to heat up and kill tumor cells.


Sun’s team envisioned heating up testis tissue to different temperatures for certain effects. They hypothesized that with a low heat, the nanorods would kill sperm cells but not sperm-producing cells, thus causing reversible contraception because the treatment would preserve the ability to produce sperm. But with a high heat, the particles would permanently damage sperm-producing cells, shutting down sperm production and leading to sterilization.


Compared to hormonal methods, Sun says, the nanorod technique would have few side effects because it does not disrupt other hormonal pathways in the body. Also, the method would be less invasive than a surgical procedure like vasectomy. While the approach could be developed for humans in the future, Sun says, it could be immediately applied to sterilize domestic animals.


As a test of the method, the researchers studied male mice in six groups. Animals in each group got a single testicular injection of one of three solutions: a saline solution, a 105 µM gold nanorod solution, or a 145 µM gold nanorod solution. The scientists then exposed the animals’ testes to near-infrared laser light at one of two power densities for about 10 minutes.

Using an infrared camera, the team found that the temperature of the mice’s testes hit between 37 and 45 °C, depending on the nanorod concentration and laser power. High concentrations and high powers lead to high temperatures. Normal mice testis tissue hovers around 29 °C.


As a fertility test, the researchers let the mice mate at seven and 60 days after treatment and calculated fertility as the percentage of pregnancies per total number of mated females. After seven days, mice that had experienced testes temperatures of 37 or 40 °C were 10% as fertile as untreated mice. Their fertility recovered to 50% at 60 days. Meanwhile, testes temperatures of 45 °C permanently sterilized the animals; all of their sperm-generating cells had died, and they produced no pups.

Diana L. Blithe, who runs a male contraception research program at the National Institute of Child Health and Human Development, says that to develop the method for people the team would need to ensure that the gold nanoparticles don’t migrate to other organs and that the laser irradiation is precisely targeted on the testes.


The method is appropriate for companion animals, says John K. Amory, a contraception researcher at the University of Washington, Seattle. But men may find it undesirable due to possible testicular pain during and after the injections. He says that long-term studies of the sterilization form of the technique will be important to ensure that the method is, in fact, permanent.

Markette Kelemete's curator insight, October 12, 2014 7:21 PM

Article examines the use of injecting gold nanorods to inactivate sperm-generating cells.

Scooped by Dr. Stefan Gruenwald!

Inhalable chemo-carrying nanoparticles target lung cancer directly

Inhalable chemo-carrying nanoparticles target lung cancer directly | Amazing Science |

U.S. researchers have developed a novel lung cancer treatment that uses nanoparticles to deliver an inhaled form of chemotherapy.


The scientists from Oregon State University, Rutgers University in New Jersey and the Cancer Institute of New Jersey developed "nanostructured lipid nanocarriers" that find cancer cells in the lung, attach to them and deliver drugs locally. With the inhaled substance, the patient receives an unadulterated form of the cancer drug compared with conventional intravenous administration, which can accumulate in other organs such as the liver or kidneys with toxic effects.


What's more, the nanoparticle comes with a bundle of small interfering RNA, siRNA, which helps silence certain genes to make the cancer cells more vulnerable to the drugs. Overall, the study showed 83% of the drug reaching its target in the lungs as opposed to 23% with the traditional approach, according to the article published in the Journal of Controlled Release.


"A drug delivery system that can be inhaled is a much more efficient approach, targeting just the cancer cells as much as possible," said co-author Oleh Taratula. "Other chemotherapeutic approaches only tend to suppress tumors, but this system appears to eliminate it."


The team has applied for a patent for the delivery platform, but human clinical trials will have to await further testing.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Graphene sensor is 1,000 times more sensitive to light, could enable ultra-low-light photography

Graphene sensor is 1,000 times more sensitive to light, could enable ultra-low-light photography | Amazing Science |

Researchers in Singapore reported that they’ve created a graphene photodetector that is roughly 800 times more sensitive than previous graphene photodetectors, and around 10 times more sensitive than the CMOS-based sensors in today’s digital cameras.


We have long known that graphene, along with being incredibly strong and electrically conductive, also has the ability to absorb light over a very broad wavelength range. Furthermore, researchers have recently confirmed that graphene has a very sensitive, hot carrier response to light (multiple electrons are fired off for every photon that hits a sheet of graphene). Both of these properties make graphene, in theory, perfect for camera sensors, photovoltaic cells, and fiber-optic communications. Now, it seems, researchers at Nanyang Technological University have actually proven it in practice.


The Singaporean graphene photodetector has a photoresponsivity of 8.61 A/W, up from previous graphene photodetectors which only manage 10 mA/W — or an increase in sensitivity of around 860 times. Hard data for silicon photodetectors, as found in your digital camera, is hard to come by, but the average seems to be around 0.8 A/W — or around 10 times less sensitive than the new graphene photodetector. This new sensor is also sensitive to a wide range of wavelengths, including visible, and near- and mid-infrared light. To achieve such high sensitivity, the researchers first create a transistor with a graphene monolayer (one-atom-thick) channel. They then deposit a varying-thickness layer of titanium on top of the graphene. This titanium layer is then etched away, leaving an array of graphene quantum dot-like (GQD) structures. This GQD then acts as the photodetector: When photons hit the GQD, the transistor turns on. Strap enough of these graphene transistors together and voila: You now have an imaging sensor.


In reality, though, and contrary to some big-name publications, this graphene sensor isn’t going to replace the silicon sensor in your camera. Graphene is still incredibly hard to work with on a commercial scale (here the researchers are still mechanically exfoliating graphene and placing it on a silicon substrate with tweezers), and there’s no indication that this method would ever scale up. What is far more likely is that these graphene photodetectors might be used in optoelectronics, where optical and electronic components are squeezed into the same system/chip, or in enabling faster fiber-optic networks.

Vloasis's curator insight, June 2, 2013 2:56 PM

Better photography to document our demise!  But seriously, if cameras make night look like day, or a dark room look lit, some smarmy technical crew should make a camera that makes the sun look like the moon.

Scooped by Dr. Stefan Gruenwald!

Tailoring optical processors: Arranging nanoparticles in geometric patterns allows for control of light with light

Tailoring optical processors: Arranging nanoparticles in geometric patterns allows for control of light with light | Amazing Science |
Rice University scientists have unveiled a robust new method for arranging metal nanoparticles in geometric patterns that can act as optical processors that transform incoming light signals into output of a different color.


Rice's team used the method to create an optical device in which incoming light could be directly controlled with light via a process known as "four-wave mixing." Four-wave mixing has been widely studied, but Rice's disc-patterning method is the first that can produce materials that are tailored to perform four-wave mixing with a wide range of colored inputs and outputs.


"Versatility is one of the advantages of this process," said study co-author Naomi Halas, director of LANP and Rice's Stanley C. Moore Professor in Electrical and Computer Engineering and a professor of biomedical engineering, chemistry, physics and astronomy. "It allows us to mix colors in a very general way. That means not only can we send in beams of two different colors and get out a third color, but we can fine-tune the arrangements to create devices that are tailored to accept or produce a broad spectrum of colors."


The information processing that takes place inside today's computers, smartphones and tablets is electronic. Each of the billions of transistors in a computer chip uses electrical inputs to act upon and modify the electrical signals passing through it. Processing information with light instead of electricity could allow for computers that are both faster and more energy-efficient, but building an optical computer is complicated by the quantum rules that light obeys.

Tom Leckrone's comment, May 26, 2013 9:37 AM
Brilliant (truly)! We are moving ever closer to Indra's Net.
Tom Leckrone's curator insight, May 26, 2013 9:49 AM

Brilliant! Non-linear = omnidirectional! I see enticing applications for process analysis, signal mixing and patten optimization within networks/communities! 

Scooped by Dr. Stefan Gruenwald!

World's smallest liquid droplets ever made in the lab, experiment suggests

World's smallest liquid droplets ever made in the lab, experiment suggests | Amazing Science |

Physicists may have created the smallest drops of liquid ever made in the lab. That possibility has been raised by the results of a recent experiment conducted by Vanderbilt physicist Julia Velkovska and her colleagues at the Large Hadron Collider, the world's largest and most powerful particle collider located at the European Laboratory for Nuclear and Particle Physics (CERN) in Switzerland. Evidence of the minuscule droplets was extracted from the results of colliding protons with lead ions at velocities approaching the speed of light.


According to the scientists' calculations, these short-lived droplets are the size of three to five protons. To provide a sense of scale, that is about one-100,000th the size of a hydrogen atom or one-100,000,000th the size of a virus.


"With this discovery, we seem to be seeing the very origin of collective behavior," said Velkovska, professor of physics at Vanderbilt who serves as a co-convener of the heavy ion program of the CMS detector, the LHC instrument that made the unexpected discovery. "Regardless of the material that we are using, collisions have to be violent enough to produce about 50 sub-atomic particles before we begin to see collective, flow-like behavior."


These tiny droplets "flow" in a manner similar to the behavior of the quark-gluon plasma, a state of matter that is a mixture of the sub-atomic particles that makes up protons and neutrons and only exists at extreme temperatures and densities. Cosmologists propose that the entire universe once consisted of this strongly interacting elixir for fractions of a second after the Big Bang when conditions were dramatically hotter and denser than they are today. Now that the universe has spent billions of years expanding and cooling, the only way scientists can reproduce this primordial plasma is to bang atomic nuclei together with tremendous energy.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

‘Nanocable’ could be big boon for energy storage

‘Nanocable’ could be big boon for energy storage | Amazing Science |

Thanks to a little serendipity, Rice University scientists have created a tiny coaxial cable that is about a thousand times smaller than a human hair and has higher capacitance than previously reported microcapacitors. This nanocable was produced with techniques pioneered in the nascent graphene research field and could be used to build next-generation energy-storage systems. It could also find use in wiring up components of lab-on-a-chip processors, but its discovery is owed partly to chance. “We didn’t expect to create this when we started,” said study co-author Jun Lou, associate professor of mechanical engineering and materials science at Rice. “At the outset, we were just curious to see what would happen electrically and mechanically if we took small copper wires known as interconnects and covered them with a thin layer of carbon.”

The tiny coaxial cable is remarkably similar in makeup to the ones that carry cable television signals into millions of homes and offices. The heart of the cable is a solid copper wire that is surrounded by a thin sheath of insulating copper oxide. A third layer, another conductor, surrounds that. In the case of TV cables, the third layer is copper again, but in the nanocable it is a thin layer of carbon measuring just a few atoms thick. The coax nanocable is about 100 nanometers, or 100 billionths of a meter, wide.


While the coaxial cable is a mainstay of broadband telecommunications, the three-layer, metal-insulator-metal structure can also be used to build energy-storage devices called capacitors. Unlike batteries, which rely on chemical reactions to both store and supply electricity, capacitors use electrical fields. A capacitor contains two electrical conductors, one negative and the other positive, that are separated by thin layer of insulation. Separating the oppositely charged conductors creates an electrical potential, and that potential increases as the separated charges increase and as the distance between them – occupied by the insulating layer — decreases. The proportion between the charge density and the separating distance is known as capacitance, and it’s the standard measure of efficiency of a capacitor.

Building entire multiple-component devices on single nanowires is a promising strategy for miniaturizing electronic applications. Here we demonstrate a single nanowire capacitor with a coaxial asymmetric Cu-Cu2O-C structure, fabricated using a two-step chemical reaction and vapour deposition method. The capacitance measured from a single nanowire device corresponds to ~140 μF cm−2, exceeding previous reported values for metal–insulator–metal micro-capacitors and is more than one order of magnitude higher than what is predicted by classical electrostatics. Quantum mechanical calculations indicate that this unusually high capacitance may be attributed to a negative quantum capacitance of the dielectric–metal interface, enhanced significantly at the nanoscale.

Andrew O'Rourke's curator insight, March 28, 2014 12:00 AM

Next-Generation energy storage utilizing nanotechnology. 

Scooped by Dr. Stefan Gruenwald!

Smallest Movie Ever: IBM Researchers Create A Nanotech Movie Out Of Atoms

Smallest Movie Ever: IBM Researchers Create A Nanotech Movie Out Of Atoms | Amazing Science |

IBM has made the tiniest stop-motion movie ever – a one-minute video of individual carbon monoxide molecules repeatedly rearranged to show a boy dancing, throwing a ball and bouncing on a trampoline.

Each frame measures 45 by 25 nanometres – there are 25 million nanometres in an inch – but hugely magnified, the movie is reminiscent of early video games, particularly when the boy bounces the ball off the side of the frame accompanied by simple music and sound effects.

Each one of the dots in the animation is one carbon monoxide molecule (one carbon atom and one oxygen atom), on top of a surface of copper. With a scanning tunneling electron microscope, the IBM researchers moved all those atoms by hand, one at a time, to create 242 individual frame of animation, seen at more than 100 million times their actual size.

 It took a team of four scientists two weeks, working 18-hour days, to create A Boy and His Atom, which works out to about 1.3 hours to produce and image each frame.

Although the project is interesting, there is a firm research interest behind it – to define the limits of magnetic data storage.  With these findings the IBM researchers determined that data can successfully be stored with 12 atoms.  Typical transistors used today use about a million atoms. To put this in context, Andreas Heinrich says that this would mean that every movie ever made could be stored on your mobile phone.  

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Researchers propose new old way to purify carbon nanotubes

Researchers propose new old way to purify carbon nanotubes | Amazing Science |

An old, somewhat passé, trick used to purify protein samples based on their affinity for water has found new fans at the National Institute of Standards and Technology.


Carbon nanotubes are formed from rolled-up sheets of carbon atoms arranged in a hexagonal pattern resembling chicken wire. One of the amazing features of nanotubes is that, depending on just how the sheet rolls up, a quality called chirality, the resulting tube can behave either like a semiconductor, with various properties, or like a metal, with electrical conductance up to 10 times better than copper. One big issue in creating commercially viable electronics based on nanotubes is being able to efficiently sort out the kind you want.


Thinking about how to do this, says NIST researcher Constantine Khripin, brought up the subject of biochemists and so-called "two-phase liquid extraction." "Biologists used this to separate proteins, even viruses," says Khripin, "It's an old technique, it was popular in the 70s, but then HPLC [high-performance liquid chromatography] replaced a lot of those techniques." People use HPLC to partition carbon nanotubes as well, he says, but it's less successful. HPLC divides things by exploiting differences in the mobility of the desired molecules as they travel small columns loaded with tiny spheres, but carbon nanotubes tend to stick to the spheres, reducing yield and eventually clogging the equipment.


The concept of liquid extraction is relatively straightforward. You make a mixture in water of two polymers that you've selected to be just slightly different in their "hydrophobicity," or tendency to mix with water. Add in your sample of stuff to be separated, stir vigorously and wait.


The polymer solutions will gradually separate into two distinct portions or "phases," the lighter one on top. And they'll bring along with them those molecules in your sample that share a similar degree of hydrophobicity.


It turns out that this works pretty well with nanotubes because of differences in their electronic structure—the semiconductor forms, for example, are more hydrophobic than the metallic forms. It's not perfect, of course, but a few sequential separations ends up with a sample where the undesired forms are essentially undetectable.


Be honest. It's not that easy. "No," agrees, Khripin, "People tried this before and it didn't work. The breakthrough was to realize that you need a very subtle difference between the two phases. The difference in hydrophobity between nanotubes is tiny, tiny, tiny." But you can engineer that with careful addition of salts and surfactants.


"This technique uses some vials and a bench-top centrifuge worth a couple hundred dollars, and it takes under a minute," observes team member Jeffrey Fagan.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Nanowires grown on graphene have surprising structure

Nanowires grown on graphene have surprising structure | Amazing Science |

When a team of University of Illinois engineers set out to grow nanowires of a compound semiconductor on top of a sheet of graphene, they did not expect to discover a new paradigm of epitaxy.

The self-assembled wires have a core of one composition and an outer layer of another, a desired trait for many advanced electronics applications. Led by professor Xiuling Li, in collaboration with professors Eric Pop and Joseph Lyding, all professors of electrical and computer engineering.


Nanowires, tiny strings of semiconductor material, have great potential for applications in transistors, solar cells, lasers, sensors and more. "Nanowires are really the major building blocks of future nano-devices," said postdoctoral researcher Parsian Mohseni, first author of the study.

"Nanowires are components that can be used, based on what material you grow them out of, for any functional electronics application."

Li's group uses a method called van der Waals epitaxy to grow nanowires from the bottom up on a flat substrate of semiconductor materials, such as silicon. The nanowires are made of a class of materials called III-V (three-five), compound semiconductors that hold particular promise for applications involving light, such as solar cells or lasers.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

By combining self-assembling DNA molecules with simple dye molecules, 3D DNA antenna harvests solar energy

By combining self-assembling DNA molecules with simple dye molecules, 3D DNA antenna harvests solar energy | Amazing Science |

Researchers at Chalmers have found an effective solution for collecting sunlight for artificial photosynthesis. By combining self-assembling DNA molecules with simple dye molecules, the researchers have created a system that resembles nature's own antenna system.


Artificial photosynthesis is one of the hot trends in energy research. A large number of the worlds' energy problems could be resolved if it were possible to recreate the ability plants have to transform solar energy into fuel. The Earth receives enough solar energy every hour to satisfy our energy needs for an entire year.


A research team at Chalmers University of Technology has made a nanotechnological breakthrough in the first step required for artificial photosynthesis. The team has demonstrated that it is possible to use self-assembling DNA molecules as scaffolding to create artificial systems that collect light. The results were recently published in the esteemed scientific Journal of the American Chemical Society. Scaffolding in plants and algae consists of a large number of proteins that organise chlorophyll molecules to ensure effective light collection. The system is complicated and would basically be impossible to construct artificially.


"It's all over if a bond breaks," says Jonas Hannestad, PhD of physical chemistry. "If DNA is used instead to organise the light-collecting molecules, the same precision is not achieved but a dynamic self-constructing system arises." With a system that builds itself, the researchers have begun to approach nature's method. If any of the light-collecting molecules break, it will be replaced with another one a second later. In this sense, it is a self-repairing system as opposed to if molecules had been put there by researchers with synthetic organic chemistry. The sun's light is moved to a reaction centre in plants and algae so they can synthesise sugars and other energy-rich molecules. "We can move energy to a reaction center, but we have not resolved how the reactions themselves are to take place there," says Bo Albinsson, professor of physical chemistry and head of the research team.


"This is actually the most difficult part of artificial photosynthesis. We have demonstrated that an antenna can easily be built. We have recreated that part of the miracle."

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Three-dimensional deep sub-diffraction optical beam lithography with 9 nm, useful for highly improved data storage

Three-dimensional deep sub-diffraction optical beam lithography with 9 nm, useful for highly improved data storage | Amazing Science |

The current nanofabrication techniques including electron beam lithography provide fabrication resolution in the nanometer range. The major limitation of these techniques is their incapability of arbitrary three-dimensional nanofabrication. This has stimulated the rapid development of far-field three-dimensional optical beam lithography where a laser beam is focused for maskless direct writing. However, the diffraction nature of light is a barrier for achieving nanometer feature and resolution in optical beam lithography. Here we report on three-dimensional optical beam lithography with 9 nm feature size and 52 nm two-line resolution in a newly developed two-photon absorption resin with high mechanical strength. The revealed dependence of the feature size and the two-line resolution confirms that they can reach deep sub-diffraction scale but are limited by the mechanical strength of the new resin. Our result has paved the way towards portable three-dimensional maskless laser direct writing with resolution fully comparable to electron beam lithography.


Compared with single-beam OBL, two-beam OBL utilizes a doughnut-shaped inhibition beam to inhibit the photopolymerization triggered by the writing beam at the doughnut ring, leading to reduced feature size and improved resolution. Although both focused writing and inhibition beams result in the spot size limited by diffraction, the fabricated feature size and resolution by two-beam OBL can break the limit defined by the diffraction spot size of the two focused beams. In fact, the smallest feature size and the highest resolution are limited by the mechanical strength of the solidified material, which can be far beyond the diffraction limit provided that an appropriate photoresin with high mechanical strength can be developed. But this breakthrough has not yet been achieved. Here, we demonstrate 3D deep sub-diffraction OBL with 9 nm (λ/42 for the wavelength of the inhibition beam) feature size and 52 nm (λ/7) two-line resolution in a resin that can efficiently harness two-photon polymerization (2PP) and single-photon inhibition.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Hierarchically nanoporous frameworks of nanocrystalline metal oxides for exceptionally high CO2 adsorption

Hierarchically nanoporous frameworks of nanocrystalline metal oxides for exceptionally high CO2 adsorption | Amazing Science |

Researchers from Ulsan National Institute of Science and Technology (UNIST), S. Korea, developed a novel, simple method to synthesize hierarchically nanoporous frameworks of nanocrystalline metal oxides such as magnesia and ceria by the thermal conversion of well-designed metal-organic frameworks (MOFs).


The novel material developed by the UNIST research team has exceptionally high CO2 adsorption capacity which could pave the way to save the Earth from CO2 pollution.


Nanoporous materials consist of organic or inorganic frameworks with a regular, porous structure. Because of their uniform pore sizes they have the property of letting only certain substances pass through, while blocking others. Nanoporous metal oxide materials are ubiquitous in materials science because of their numerous potential applications in various areas, including adsorption, catalysis, energy conversion and storage, optoelectronics, and drug delivery.


While synthetic strategies for the preparation of siliceous nanoporous materials are well-established, non-siliceous metal oxide-based nanoporous materials still present challenges.


A description of the new research was published (Web) on May 7 in the Journal of the American Chemical Society. (Title: Nanoporous Metal Oxides with Tunable and Nanocrystalline Frameworks via Conversion of Metal-Organic Frameworks) This article will be also highlighted in the Editor's Choice of the journal Science.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Sensing individual biomolecules with optical sensors inside nanoboxes

Sensing individual biomolecules with optical sensors inside nanoboxes | Amazing Science |

A single cell in our body is composed of thousands of millions of different biomolecules that work together in an extremely well-coordinated way. Likewise, many biological and biochemical reactions occur only if molecules are present at very high concentrations. Understanding how all these molecules interact with each other is key to advancing our knowledge in molecular and cell biology. This knowledge is of central and fundamental importance in the quest for the detection of the earliest stages of many human diseases. As such, one of ultimate goals in Life Sciences and Biotechnology is to observe how individual molecules work and interact with each other in these very crowded environments. Unfortunately, detecting one molecule amongst millions of neighbouring molecules has been technically impossible until now. The key to successfully detecting the single molecule lies in the conception and production of a working device that shrinks the observation region to a tiny size that is comparable to the size of the molecule itself, i.e. only a few nanometres.


Researchers at the Fresnel Institute in Marseille and ICFO-the Institute for Photonic Sciences in Barcelona report in Nature Nanotechnology the design and fabrication of the smallest optical device, capable of detecting and sensing individual biomolecules at concentrations that are similar to those found in the cellular context. The device called "antenna-in-a-box" consists on a tiny dimer antenna made out of two gold semi-spheres, separated from each other by a gap as small as 15nm. Light sent to this antenna is enormously amplified in the gap region where the actual detection of the biomolecule of interest occurs. Because amplification of the light is confined to the dimensions of the gap, only molecules present in this tiny region are detected. A second trick that the researchers used to make this device work was to embed the dimer antennas inside boxes also of nanometric dimensions. "The box screens out the unwanted "noise" of millions of other surrounding molecules, reducing the background and improving as a whole the detection of individual biomolecules.", explains Jerome Wenger from Fresnel Institute. When tested under different sample concentrations, this novel antenna-in-box device allowed for 1100-fold fluorescence brightness enhancement together with detection volumes down to 58 zeptoliters (1 zL = 10E-21L), i.e., the smallest observation volume in the world.


The antenna-in-a-box offers a highly efficient platform for performing a multitude of nanoscale biochemical assessments with single molecule sensitivity at physiological conditions. It could be used for ultrasensitive sensing of minute amounts of molecules, becoming an excellent early diagnosis device for biosensing of many disease markers. "It can also be used as an ultra-bright optical nanosource to illuminate molecular processes in living cells and ultimately visualize how individual biomolecules interact with each other. This brings us closer to the long awaited dream of biologists", concludes ICFO researcher Prof. Maria Garcia-Parajo.

Marcus Taylor's curator insight, July 29, 2013 9:20 PM

This antenna-in-box is amazing stuff. I had never heard of a zeptoliter before. It will allow us to peer into cells and get feedback on treatments.

Scooped by Dr. Stefan Gruenwald!

Fine-tuning emission spectra from quantum dots by photon-correlation Fourier spectroscopy in solution

Fine-tuning emission spectra from quantum dots by photon-correlation Fourier spectroscopy in solution | Amazing Science |

New MIT analysis should enable development of improved color displays and biomedical monitoring systems. The new method — called photon-correlation Fourier spectroscopy in solution — makes it possible to extract single-particle spectral properties from a large group of particles. While it doesn’t tell you the spectral peak width of a specific particle, it does give you the average single-particle spectral width from billions of particles, revealing whether the individual particles produce pure colors or not.

In addition, the particles “are not isolated on a surface, but are in their natural environment, in a solution. With the traditional methods, there’s always a question: How much does the surface affect the results?

The method works by comparing pairs of photons emitted by individual particles. That doesn’t tell you the absolute color of any particular particle, but it does give a representative statistical measure of the whole collection of particles. It does this by illuminating the sample solution with a laser beam and detecting the emitted light at extremely short time scales. So while different particles are not differentiated in space, they can be differentiated in time, as they drift in and out of the narrow laser beam and are turned on by the beam.

By applying this method to the production of quantum dot nanocrystals, the MIT team can determine how well different methods of synthesizing the particles work.

“It was an open question whether the single-dot line widths were variable or not,” Cui says. Now, he and his colleagues can determine this for each variation in the fabrication process, and start to fine-tune the process to produce the most useful output for different applications.

In addition to computer displays, such particles have applications in biomedical research, where they are used as staining agents for different biochemicals. The more precise the colors of the particles are, the greater the number of different colored particles that can be used at once in a sample, each targeted to a different kind of biomolecule.

Using this method, the researchers were able to show that a widely used material for quantum dots, cadmium selenide, does indeed produce very pure colors. But, they found that other materials that could replace cadmium selenide or produce different colors, such as indium phosphide, can also have intrinsically very pure colors. Previously, this was an open question. 

Todd Krauss, a professor of chemistry at the University of Rochester who was not involved in this research, says the MIT team’s “approach is very clever and builds on what this group has done previously.” Measuring the line widths of individual particles is important, he says, in optimizing applications such as television displays and biological markers. He adds, “We should be able to make much better strides now that this technique is published, because of the ability to get single-particle line widths on many particles at once.”

No comment yet.
Scooped by Dr. Stefan Gruenwald!

New crystals that glow in different colors may illuminate homes and offices as effectively as natural sunlight

New crystals that glow in different colors may illuminate homes and offices as effectively as natural sunlight | Amazing Science |

Minuscule crystals that glow different colors may be the missing ingredient for white LED lighting that illuminates homes and offices as effectively as natural sunlight.


Light-emitting diodes, better known as LEDs, offer substantial energy savings over incandescent and fluorescent lights and are easily produced in single colors such as red or green commonly used in traffic lights or children's toys. Developing an LED that emits a broad spectrum of warm white light on par with sunlight has proven tricky, however. LEDs, which produce light by passing electrons through a semiconductor material, often are coupled with materials called phosphors that glow when excited by radiation from the LED.


"But it's hard to get one phosphor that makes the broad range of colors needed to replicate the sun," said John Budai, a scientist in ORNL's Materials Science and Technology division. "One approach to generating warm-white light is to hit a mixture of phosphors with ultraviolet radiation from an LED to stimulate many colors needed for white light."


Budai is working with a team of scientists from University of Georgia and Oak Ridge and Argonne national laboratories to understand a new group of crystals that might yield the right blend of colors for white LEDs as well as other uses. Zhengwei Pan's group at UGA grew the nanocrystals using europium oxide and aluminum oxide powders as the source materials because the rare-earth element europium is known to be a dopant, or additive, with good phosphorescent properties.


"What's amazing about these compounds is that they glow in lots of different colors—some are orange, purple, green or yellow," Budai said. "The next question became: why are they different colors? It turns out that the atomic structures are very different."


Budai has been studying the atomic structure of the materials using x-rays from Argonne's Advanced Photon Source. Two of the three types of crystal structures in the group of phosphors had never been seen before, which can probably be attributed to the crystals' small size, Budai said.


"Only the green ones were a known crystal structure," Budai said. "The other two, the yellow and blue, don't grow in big crystals; they only grow with these atomic arrangements in these tiny nanocrystals. That's why they have different photoluminescent properties."


X-ray diffraction analysis is helping Budai and his collaborators work out how the atoms are arranged in each of the different crystal types. The different-colored phosphors exhibit distinct diffraction patterns when they are hit with x-rays, enabling researchers to analyze the crystal structure.

"What that means in terms of how the electrons around the atoms interact to make light is much harder," Budai said. "We haven't completely solved that yet. That's the continuing research. We have a lot of clues, but we don't know everything."


The knowledge gained through their atomic-scale analysis is helping the research team improve the phosphorescent crystals. Different factors in the growth process—temperature, powder composition, and types of gas used—can change the final product. A fundamental understanding of all the parameters could help the team to perfect the recipe and improve the crystals' ability to convert energy into light.


Advancing the material's luminescence efficiency is key to making it useful for commercial LED products and other applications; the new nanocrystals may turn out to have other practical photonic uses beyond phosphors for LEDs. Their ability to act as miniature "light pipes" when the crystal quality is high enough could lend them to applications in fiber-optic technologies, Budai said.


"You can keep growing the crystals and measuring them, or you can understand why it's doing what it's doing, and figure out how to make it better. That's what we're doing—basic research. We have to figure out nature first."

Vloasis's curator insight, June 6, 2013 8:20 AM

It's rather exciting to be living in a time when new forms of light are being invented!

Scooped by Dr. Stefan Gruenwald!

Charred micro-bunny sculpture shows promise of new 3-D shaping material

Charred micro-bunny sculpture shows promise of new 3-D shaping material | Amazing Science |

Though its surface has been turned to carbon, the bunny-like features can still be easily observed with a microscope. This rabbit sculpture, the size of a typical bacterium, is one of several whimsical shapes created by a team of Japanese scientists using a new material that can be molded into complex, highly conductive 3-D structures with features just a few micrometers across. Combined with state-of-the-art micro-sculpting techniques, the new resin holds promise for making customized electrodes for fuel cells or batteries, as well as biosensor interfaces for medical uses. The research team, which includes physicists and chemists from Yokohama National University, Tokyo Institute of Technology, and the company C-MET, Inc., presents its results in a paper published today in the Optical Society's (OSA) open-access journal Optical Materials Express.


The work opens a door for researchers trying to create conductive materials in almost any complex shape at the microscopic or cellular level. "One of the most promising applications is 3-D microelectrodes that could interface with the brain," says Yuya Daicho, graduate student at Yokohama National University and lead author of the paper. These brain interfaces, rows of needle-shaped electrodes pointing in the same direction like teeth on combs, can send or receive electrical signals from neurons and can be used for deep brain stimulation and other therapeutic interventions to treat disorders such as epilepsy, depression, and Parkinson's disease. "Although current microelectrodes are simple 2-D needle arrays," Daicho says, "our method can provide complex 3-D electrode arrays" in which the needles of a single device have different lengths and tip shapes, giving researchers more flexibility in designing electrodes for specialized purposes. The authors also envision making microscopic 3-D coils for heating applications.


Currently, researchers have access to materials that can be used to make complex 3-D structures. But the commercially available resins that work best with modern 3-D shaping techniques do not respond to carbonization, a necessary part of the electrode preparation process. In this stage, a structure is baked at a temperature high enough to turn its surface to carbon. The process of "carbonizing," or charring, increases the conductivity of the resin and also increases its surface area, both of which make it a good electrode. Unfortunately, this process also destroys the resin's shape; a sphere becomes an unrecognizable charred blob. What researchers needed were new materials that could be crafted using 3-D shaping techniques but that would also survive the charring process.


The Japanese team, led by Daicho and his advisor Shoji Maruo, sought to develop materials that would fit these needs. Trained as a chemist, Daicho developed a light-sensitive resin that included a material called Resorcinol Diglycidyl Ether (RDGE), typically used to dilute other resins but never before used in 3-D sculpting. The new mixture had a unique advantage over other compounds -- it was a liquid, and therefore potentially suitable for manipulation using the preferred 3-D sculpting methods.


Daicho, Maruo, and colleagues tested three different concentrations of RDGE in their new compounds. Though there was shrinkage, the materials held their shapes during the charring process (controlled shrinkage of a microstructure can be a good thing in cases where miniaturization of a structure is desired). The resin with the lowest concentration of RDGE shrank 30 percent, while that with the highest concentration shrank 20 percent.


The researchers also tested their new resin's ability to be manipulated using techniques specifically suited for 3-D shaping. In one technique, called microtransfer molding, the light-sensitive liquid was molded into a desired shape and then hardened by exposure to ultraviolet (UV) light. The other technique, preferred because of its versatility, made use of the liquid resin's property of solidifying when exposed to a laser beam. In this process, called two-photon polymerization, researchers used the laser to "draw" a shape onto the liquid resin and build it up layer by layer. Once the objects were shaped, they were carbonized and viewed with a scanning electron microscope (SEM).


In addition to crafting pyramids and discs, the researchers reproduced the well-known "Stanford bunny," a shape commonly used in 3-D modeling and computer graphics. Maruo says that when he first saw a picture of the rabbit structure taken with the SEM, he was delighted at how well it had held up during the charring process.


"When we got the carbon bunny structure, we were very surprised," Maruo says. It was exciting, he continues, to see that "even with a very simple experimental structure, we could get this complicated 3-D carbon microstructure." The rabbit's shape would be much more difficult, expensive, and time-consuming to create using any of the existing processes compatible with carbonization, he adds.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Nano-antennas Improve Infrared Sensing

Nano-antennas Improve Infrared Sensing | Amazing Science |

A team of University of Pennsylvania engineers has used a pattern of nanoantennas to develop a new way of turning infrared light into mechanical action, opening the door to more sensitive infrared cameras and more compact chemical-analysis techniques.


The research was conducted by assistant professor Ertugrul Cubukcu and postdoctoral researcher Fei Yi, along with graduate students Hai Zhu and Jason C. Reed, all of the Department of Material Scienceand Engineering in Penn’s School of Engineering and Applied Science.  


Detecting light in the mid-infrared range is important for applications like night-vision cameras, but it can also be used to do spectroscopy, a technique that involves scattering light over a substance to infer its chemical composition. Existing infrared detectors use cryogenically cooled semiconductors, or thermal detectors known as microbolometers, in which changes in electrical resistance can be correlated to temperatures. These techniques have their own advantages, but both need expensive, bulky equipment to be sensitive enough for spectroscopy applications.


“We set out to make an optomechanical thermal infrared detector,” Cubukcu said. “Rather than changes in resistance, our detector works by connecting mechanical motion to changes in temperature.”


The advantage to this approach is that it could reduce the footprint of an infrared sensing device to something that would fit on a disposable silicon chip. The researchers fabricated such a device in their study.


At the core of the device is a nanoscale structure — about a tenth of a millimeter wide and five times as long — made of a layer of gold bonded to a layer of silicon nitride. The researchers chose these materials because of their different thermal expansion coefficients, a parameter that determines how much a material will expand when heated. Because metals will naturally convert some energy from infrared light into heat, researchers can connect the amount the material expands to the amount of infrared light hitting it.    


“A single layer would expand laterally, but our two layers are constrained because they’re attached to one another,” Cubukcu said. “The only way they can expand is in the third dimension. In this case, that means bending toward the gold side, since gold has the higher thermal expansion coefficient and will expand more.”


To measure this movement, the researchers used a fiber interferometer. A fiber optic cable pointed upward at this system bounces light off the underside of the silicon nitride layer, enabling the researchers to determine how far the structure has bent upwards. 


“We can tell how far the bottom layer has moved based on this reflected light,” Cubukcu said. “We can even see displacements that are thousands of times smaller than a hydrogen atom.”

Tom Leckrone's curator insight, May 26, 2013 9:51 AM

Excerpt: “A single layer would expand laterally, but our two layers are constrained because they’re attached to one another,” Cubukcu said. “The only way they can expand is in the third dimension. In this case, that means bending toward the gold side, since gold has the higher thermal expansion coefficient and will expand more.”

Scooped by Dr. Stefan Gruenwald!

DNA-guided assembly yields novel ribbon-like nanostructures

DNA-guided assembly yields novel ribbon-like nanostructures | Amazing Science |

Scientists at the U.S. Department of Energy's Brookhaven National Laboratory have discovered that DNA "linker" strands coax nano-sized rods to line up in way unlike any other spontaneous arrangement of rod-shaped objects. The arrangement -- with the rods forming "rungs" on ladder-like ribbons linked by multiple DNA strands -- results from the collective interactions of the flexible DNA tethers and may be unique to the nanoscale.

"This is a completely new mechanism of self-assembly that does not have direct analogs in the realm of molecular or microscale systems," said Brookhaven physicist Oleg Gang, lead author on the paper, who conducted the bulk of the research at the Lab's Center for Functional Nanomaterials.


Broad classes of rod-like objects, ranging from molecules to viruses, often exhibit typical liquid-crystal-like behavior, where the rods align with a directional dependence, sometimes with the aligned crystals forming two-dimensional planes over a given area. Rod shaped objects with strong directionality and attractive forces between their ends-resulting, for example, from polarized charge distribution-may also sometimes line up end-to-end forming linear one-dimensional chains.

Using synthetic DNA as a form of molecular glue to guide nanoparticle assembly has been a central approach of Gang's research at the CFN. His previous work has shown that strands of this molecule-better known for carrying the genetic code of living things-can pull nanoparticles together when strands bearing complementary sequences of nucleotide bases (known by the letters A, T, G, and C) are used as tethers, or inhibit binding when unmatched strands are used. Carefully controlling those attractive and inhibitory forces can lead to fine-tuned nanoscale engineering.


In the current study, the scientists used gold nanorods and single strands of DNA to explore arrangements made with complementary tethers attached to adjacent rods. They also examined the effects of using linker strands of varying lengths to serve as the tethering glue.


After mixing the various combinations, they studied the resulting arrangements using ultraviolet-visible spectroscopy at the CFN, and also with small-angle x-ray scattering at Brookhaven's National Synchrotron Light Source (NSLS, They also used techniques to "freeze" the action at various points during assembly and observed those static phases using scanning electron microscopy to get a better understanding of how the process progressed over time.


The various analysis methods confirmed the side-by-side arrangement of the nanorods arrayed like rungs on a ladder-like ribbon during the early stages of assembly, followed later by stacking of the ribbons and finally larger-scale three-dimensional aggregation due to the formation of DNA bridges between the ribbons.


This staged assembly process, called hierarchical, is reminiscent of self-assembly in many biological systems, for example, the linking of amino acids into chains followed by the subsequent folding of these chains to form functional proteins.


The stepwise nature of the assembly suggested to the team that the process could be stopped at the intermediate stages. Using "blocker" strands of DNA to bind up the remaining free tethers on the linear ribbon-like structures, they demonstrated their ability to prevent the later-stage interactions that form aggregate structures.


"Stopping the assembly process at the ladder-like ribbon stage could potentially be applied for the fabrication of linear structures with engineered properties," Gang said. "For example by controlling plasmonic or fluorescent properties-the materials' responses to light-we might be able to make nanoscale light concentrators or light guides, and be able to switch them on demand."

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Big drugmakers think small with nanomedicine deals

Big drugmakers think small with nanomedicine deals | Amazing Science |

Is nanomedicine the next big thing? A growing number of top drug companies seem to think so. The ability to encapsulate potent drugs in tiny particles measuring billionths of a metre in diameter is opening up new options for super-accurate drug delivery, increasing precision hits at the site of disease with, hopefully, fewer side effects.


Three deals struck this year by privately held Bind Therapeutics, together worth nearly $1 billion if experiments are successful, highlight a new interest in using such tiny carriers to deliver drug payloads to specific locations in the body.


U.S.-based Bind is one of several biotechnology firms that are luring large pharmaceutical makers with a range of smart drug nanotechnologies, notably against cancer.


And nanomedicine is also being put to work in diagnosis, with tiny particles used to improve imaging in scanners, as well as rapidly detecting some serious infections.


In future, researchers hope to combine both treatment and diagnostics in a new approach dubbed "theranostics" that would allow doctors to monitor patients via their medicines.


After much hype but limited clinical success, scientists in the nanotechnology field finally see a turning point. "We have been hearing about the promise of nanomedicine for a long time, but it is now really starting to move," said Dan Peer, who runs a nanomedicine laboratory at Tel Aviv University.


"There is a new level of confidence in this approach among the big pharmaceutical companies ... We will see more and more products in clinical testing over the next few years and I think that is very exciting."

Nanoparticles made of polymers, gold and even graphene - a newly-discovered form of carbon - are now in various stages of development. In cancer alone, 117 drugs are being assessed using nanoparticle formulations, though most have yet to be tried on patients, according to Thomson Reuters Pharma data.


Other potential applications include treatments for inflammatory disorders, heart and brain diseases, and pain.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Injectable nano-network controls blood sugar in diabetics for days at a time

Injectable nano-network controls blood sugar in diabetics for days at a time | Amazing Science |

In a promising development for diabetes treatment, researchers have developed a network of nanoscale particles that can be injected into the body and release insulin when blood-sugar levels rise, maintaining normal blood sugar levels for more than a week in animal-based laboratory tests. The work was done by researchers at North Carolina State University, the University of North Carolina at Chapel Hill, the Massachusetts Institute of Technology and Children's Hospital Boston.


The new, injectable nano-network is composed of a mixture containing nanoparticles with a solid core of insulin, modified dextran and glucose oxidase enzymes. When the enzymes are exposed to high glucose levels they effectively convert glucose into gluconic acid, which breaks down the modified dextran and releases the insulin. The insulin then brings the glucose levels under control. The gluconic acid and dextran are fully biocompatible and dissolve in the body.


Each of these nanoparticle cores is given either a positively charged or negatively charged biocompatible coating. The positively charged coatings are made of chitosan (a material normally found in shrimp shells), while the negatively charged coatings are made of alginate (a material normally found in seaweed).


When the solution of coated nanoparticles is mixed together, the positively and negatively charged coatings are attracted to each other to form a "nano-network." Once injected into the subcutaneous layer of the skin, the nano-network holds the nanoparticles together and prevents them from dispersing throughout the body. Both the nano-network and the coatings are porous, allowing blood -- and blood sugar -- to reach the nanoparticle cores.


"This technology effectively creates a 'closed-loop' system that mimics the activity of the pancreas in a healthy person, releasing insulin in response to glucose level changes," Gu says. "This has the potential to improve the health and quality of life of diabetes patients."


Gu's research team is currently in discussions to move the technology into clinical trials for use in humans.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Discovery yields supertough, strong nanofibers

Discovery yields supertough, strong nanofibers | Amazing Science |

Strength of structural materials and fibers is usually increased at the expense of strain at failure and toughness. Recent experimental studies have demonstrated improvements in modulus and strength of electrospun polymer nanofibers with reduction of their diameter. Nanofiber toughness has not been analyzed; however, from the classical materials property trade-off, one can expect it to decrease. Here, on the basis of a comprehensive analysis of long (5–10 mm) individual polyacrylonitrile nanofibers, we show that nanofiber toughness also dramatically improves.


Reduction of fiber diameter from 2.8 μm to 100 nm resulted in simultaneous increases in elastic modulus from 0.36 to 48 GPa, true strength from 15 to 1750 MPa, and toughness from 0.25 to 605 MPa with the largest increases recorded for the ultrafine nanofibers smaller than 250 nm. The observed size effects showed no sign of saturation. Structural investigations and comparisons with mechanical behavior of annealed nanofibers allowed us to attribute ultrahigh ductility (average failure strain stayed over 50%) and toughness to low nanofiber crystallinity resulting from rapid solidification of ultrafine electrospun jets. Demonstrated superior mechanical performance coupled with the unique macro-nano nature of continuous nanofibers makes them readily available for macroscopic materials and composites that can be used in safety-critical applications. The proposed mechanism of simultaneously high strength, modulus, and toughness challenges the prevailing 50 year old paradigm of high-performance polymer fiber development calling for high polymer crystallinity and may have broad implications in fiber science and technology.

No comment yet.