Medical Sensors Improve With Holey Gold Nanostructures

Sep. 26, 2013 — A new method that fabricates gold nanostructures quickly and efficiently could lead to highly sensitive, portable medical sensorsRecent advances in nanotechnology are providing new possibilities for medical imaging and sensing. Gold nanostructures, for example, can enhance the fluorescence of marker dyes that are commonly used to detect biomolecules and diagnose specific diseases.

Localized surface plasmon resonance (bright areas) around a gold nanohole enhances the fluorescence of a biomarker dye (Y-shaped molecule) when a specific molecule of interest (purple circle) is present. (Credit: A*STAR Institute of High Performance Computing)

Now, Ping Bai at the A*STAR Institute of High Performance Computing, Singapore, and co-workers have developed a fast and inexpensive way to fabricate arrays of gold nanoholes. The researchers have shown that sensor chips built using these nanostructures can accurately detect cancer-related molecules in blood and are small enough to be used in portable medical devices.
Nanohole arrays are designed so that incident light of certain wavelengths will induce large-scale oscillations of the gold electrons, known as localized surface plasmon resonance (SPR). The localized SPR focuses the absorbed light energy to enhance fluorescence (see image).
"Commercial SPR systems are already used in hospital laboratories, but they are bulky and expensive," says Bai. "We would like to develop small, handheld devices for on-the-spot clinical use. This requires localized SPR, for which we need nanohole arrays."
Previously, nanohole arrays have been created using electron-beam lithography (EBL), which is expensive and time consuming. Bai and co-workers used EBL to create a nickel mold and then used the mold to print nanohole patterns onto a photoresist material. The researchers made the nanostructures by evaporating gold onto the patterned structure before peeling off the photoresist material. Because the nickel mold can be reused many times, this method -- called nano-imprinting -- can produce large numbers of gold nanohole arrays.
"We fabricated arrays of 140 nanometer-square nanoholes with very few defects," says Bai. As a first demonstration, the researchers showed that a sensor chip made with their nanohole arrays could detect prostate cancer antigens in blood, and was ten times more sensitive than an identical device that used a gold film without nanoholes. Optimizing the chip design would further improve the sensitivity, Bai notes.
The team believes that these chips could be incorporated into cheap and portable point-of-care devices for rapid diagnosis of diseases such as dengue fever. "The microfluidic cartridge built using our nanohole arrays is about the size of a credit card," says Bai. "In the future, we hope to build detectors that use very simple light sources, such as LEDs, and simple detectors similar to smartphone cameras. These devices will have widespread applications across medical science and could even be used to detect contaminants in food, water or the air."

 

Accelerator On a Chip: Technology Could Spawn New Generations of Smaller, Less Expensive Devices for Science, Medicine

The key to the accelerator chips is tiny, precisely spaced ridges, which cause the iridescence seen in this close-up photo. (Credit: Matt Beardsley, SLAC National Accelerator Laboratory)

The achievement was reported today in Nature by a team including scientists from the U.S. Department of Energy's (DOE) SLAC National Accelerator Laboratory and Stanford University.
"We still have a number of challenges before this technology becomes practical for real-world use, but eventually it would substantially reduce the size and cost of future high-energy particle colliders for exploring the world of fundamental particles and forces," said Joel England, the SLAC physicist who led the experiments. "It could also help enable compact accelerators and X-ray devices for security scanning, medical therapy and imaging, and research in biology and materials science."
Because it employs commercial lasers and low-cost, mass-production techniques, the researchers believe it will set the stage for new generations of "tabletop" accelerators.
At its full potential, the new "accelerator on a chip" could match the accelerating power of SLAC's 2-mile-long linear accelerator in just 100 feet, and deliver a million more electron pulses per second.
This initial demonstration achieved an acceleration gradient, or amount of energy gained per length, of 300 million electronvolts per meter. That's roughly 10 times the acceleration provided by the current SLAC linear accelerator.
"Our ultimate goal for this structure is 1 billion electronvolts per meter, and we're already one-third of the way in our first experiment," said Stanford Professor Robert Byer, the principal investigator for this research.
Today's accelerators use microwaves to boost the energy of electrons. Researchers have been looking for more economical alternatives, and this new technique, which uses ultrafast lasers to drive the accelerator, is a leading candidate.
Particles are generally accelerated in two stages. First they are boosted to nearly the speed of light. Then any additional acceleration increases their energy, but not their speed; this is the challenging part.
In the accelerator-on-a-chip experiments, electrons are first accelerated to near light-speed in a conventional accelerator. Then they are focused into a tiny, half-micron-high channel within a fused silica glass chip just half a millimeter long. The channel had been patterned with precisely spaced nanoscale ridges. Infrared laser light shining on the pattern generates electrical fields that interact with the electrons in the channel to boost their energy.
Turning the accelerator on a chip into a full-fledged tabletop accelerator will require a more compact way to get the electrons up to speed before they enter the device.
A collaborating research group in Germany, led by Peter Hommelhoff at the Max Planck Institute of Quantum Optics, has been looking for such a solution. It simultaneously reports in Physical Review Letters its success in using a laser to accelerate lower-energy electrons.
Applications for these new particle accelerators would go well beyond particle physics research. Byer said laser accelerators could drive compact X-ray free-electron lasers, comparable to SLAC's Linac Coherent Light Source, that are all-purpose tools for a wide range of research.

Another possible application is small, portable X-ray sources to improve medical care for people injured in combat, as well as provide more affordable medical imaging for hospitals and laboratories. That's one of the goals of the Defense Advanced Research Projects Agency's (DARPA) Advanced X-Ray Integrated Sources (AXiS) program, which partially funded this research. Primary funding for this research is from the DOE's Office of Science.
 

 

Lernstift – a Pen That Warns for Mistakes

Lernstift is a digital pen  

that recognizes writing errors and points them out with a subtle vibration – like a friend looking you over the shoulder as you write. Lernstift works fully autonomous – without further external devices or special paper.

Two central functions

Learning to write bears two main challenges: writing legibly and writing correctly. Lernstift helps with both – from legibly writing one's very first letters down to the correct spelling of exotic fruits on your shopping list.

Calligraphy mode

In Calligraphy Mode the pen vibrates once if a letter is written wrong or illegibly.

Orthography mode

In Orthography Mode the pen vibrates once for a misspelled word and twice to point out grammatical errors in a sentence.

Lernstift Apps

Lernstift is an innovative learning aid for kids and adults.
The sophisticated electronics recognize all writing movements and points out mistakes as they are being made – with an unmistakeable vibration.

Via Wi-Fi the pen can be connected to computers and smart devices. With the help of apps one can measure the learning progress. A broad range of other apps will be developed – from interactive learning games to digital note-taking and co-writing solutions all the way down to social media sharing and an own Lernstift community.

Learning success measurement

Live monitoring

Document creation

Cowriting

Further Features

Unlike other digital pens Lernstift is truly multifaceted – in both the visual and functional design.

Exchangeable writing tips: pencil, fountain pen, ballpoint

With its exhangeable writing system the pen can be easily turned into a pencil, fountain pen or ballpoint.

Color variants for girls and boys, mothers and fathers

Boys will be boys and most girls do have a feminine style most of the time; that's why Lernstift will be available in respective colors.

Language versions

Upon launch, Lernstift will be available in English and German. Step by step we will then introduce further languages; depending on the demand.

The future of penmanship

A perfectly easy way to learn to write perfectly

For centuries mankind has been learning to write. All this time, we have depended on someone looking over our shoulder as we write, or correcting spelling, grammar and form afterwards.
In the future we can get our feedback another way – and more importantly: instantly! With Lernstift. It combines a time-tested writing utensil with state of the art technology and thereby gives writing by hand new relevance and appeal in the age of the iPad.
The integrated electronics recognize mistakes as they are being made and give the writer feedback by vibrating. In other words:

Lernstift is a great way to learn how to write faster. And what’s more: Lernstift is great fun, too!

Lernstift – a Pen That Warns for Mistakes

Lernstift – a Pen That Warns for Mistakes

Army test next generation nano drone - the Black Hornet

Army test next generation nano drone - the Black Hornet

It may look like a child’s toy - but this tiny remote control helicopter has become massively important to the Army in the fight against the Taliban

High flyer: Sgt Scott Weaver launches a drone

Crown Copyright

It may look like a child’s toy - but this tiny remote control helicopter has become massively important to the Army in the fight against the Taliban.
Troops in Afghanistan program the Black Hornet drone to fly deep into enemy territory and take pictures with three tiny cameras fitted in its nose before returning to base.

The 8in drones are so small that they can fit easily in a soldier’s hand and weigh just over half an ounce including their batteries.
They are being used by soldiers from the Brigade Reconnaissance Force at Camp Bastion in Afghanistan.

Mission: The Black Hornet takes off at Camp Bastion

Crown Copyright

 

Child's play: The remote control helicopter in the air

Crown Copyright

  Commanding officer Major Adam Foden, 53, said: “Black Hornet is a game-changing piece of kit.
"Previously, we would have had to send soldiers forward to see if there were any enemy fighters hiding inside a set of buildings.
"Now we are deploying Black Hornet to look inside compounds and to clear a route through enemy-held spaces.
“It has worked very well and the pictures it delivers back to the monitor are really clear and Black Hornet is so small and quiet that the locals can’t see or hear it.”
The Black Hornet has a rechargeable battery and is controlled by members of the unit using a joystick similar to those on video games .
The drone can fly at speeds of up to 22mph during each 30-minute reconnaissance mission.
As it hovers near enemy positions, high-resolution images are beamed back to Camp Bastion.
One soldier said: “The Black Hornet is really cool. The pictures are amazingly clear and we can see who is a local civilian and who is a Taliban fighter and whether any weapons are being stored there.
“We can then make our plans accordingly. It saves a lot of time and prevents a lot of mistakes.
"It can zoom right up to somebody’s face and hold that frame for as long as is required so we can identify them without them even knowing it’s there.”
 
Hi-tech and deadly
British soldiers operating in Afghanistan are equipped with a variety of hi-tech equipment.
The latest rifle – the SA80 A2 – is fitted with a high-definition sight which helps them to pinpoint targets more quickly.
The A2 has a range of up to 300 metres and has been used to devastating effect.
It is superior to its predecessors because it is fully automatic and sealed so less likely to get sand in it.
Troops are also supplied with state-of-the-art sunglasses which protect them from bomb blasts as well as sunlight.
The glasses are fitted with yellow lenses which enable them to make eye contact with civilians – which is seen as highly important when communicating.