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Designer's toolkit for dynamic DNA: Arm-waving nanorobot signals new flexibility in DNA origami

Designer's toolkit for dynamic DNA: Arm-waving nanorobot signals new flexibility in DNA origami | Amazing Science | Scoop.it

The latest DNA nanodevices created at the Technische Universitaet Muenchen (TUM) - including a robot with movable arms, a book that opens and closes, a switchable gear, and an actuator - may be intriguing in their own right, but that's not the point. They demonstrate a breakthrough in the science of using DNA as a programmable building material for nanometer-scale structures and machines. Results published in the journalScience reveal a new approach to joining - and reconfiguring - modular 3D building units, by snapping together complementary shapes instead of zipping together strings of base pairs. This not only opens the way for practical nanomachines with moving parts, but also offers a toolkit that makes it easier to program their self-assembly.


The field popularly known as "DNA origami," in reference to the traditional Japanese art of paper folding, is advancing quickly toward practical applications, according to TUM Prof. Hendrik Dietz. Earlier this month, Dietz was awarded Germany's most important research award, the Gottfried Wilhelm Leibniz Prize, for his role in this progress.


In recent years, Dietz and his team have been responsible for major steps in the direction of applications: experimental devices including a synthetic membrane channel made from DNA; discoveries that cut the time needed for self-assembly processes from a week to a few hours and enable yields approaching 100%; proof that extremely complex structures can be assembled, as designed, with subnanometer precision. Yet all those advances employed "base-pairing" to determine how individual strands and assemblies of DNA would join up with others in solution. What's new is the "glue."


"Once you build a unit with base pairs," Dietz explains, "it's hard to break apart. So dynamic structures made using that approach tended to be structurally simple." To enable a wider range of DNA nanomachines with moving parts and potentially useful capabilities, the team adapted two more techniques from nature's biomolecular toolkit: the way proteins use shape complementarity to simplify docking with other molecules, and their tendency to form relatively weak bonds that can be readily broken when no longer needed.


For the experiments reported in Science, Dietz and his co-authors took inspiration from a mechanism that allows nucleic acid molecules to bond through interactions weaker than base-pairing. In nature, weak bonds can be formed when the RNA-based enzyme RNase P "recognizes" so-called transfer RNA; the molecules are guided into close enough range, like docking spacecraft, by their complementary shapes.


The new technology from Dietz's lab imitates this approach. To create a dynamic DNA nanomachine, the researchers begin by programming the self-assembly of 3D building blocks that are shaped to fit together. A weak, short-ranged binding mechanism called nucleobase stacking can then be activated to snap these units in place. Three different methods are available to control the shape and action of devices made in this way.


What this has given us is a tiered hierarchy of interaction strengths," Dietz says, "and the ability to position - precisely where we need them - stable domains that can recognize and interact with binding partners." The team produced a series of DNA devices - ranging from micrometer-scale filaments that might prefigure technological "flagella" to nanoscale machines with moving parts - to demonstrate the possibilities and begin testing the limits.


For example, transmission electron micrographs of a three-dimensional, nanoscale humanoid robot confirm that the pieces fit together exactly as designed. In addition, they show how a simple control method - changing the concentration of positive ions in solution - can actively switch between different configurations: assembled or disassembled, with "arms" open wide or resting at the robot's side.

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First Graphene Cytobot: Graphene Quantum Dots Interfaced with A Single Bacterial Spore

First Graphene Cytobot: Graphene Quantum Dots Interfaced with A Single Bacterial Spore | Amazing Science | Scoop.it

UIC researchers created an electromechanical device--a humidity sensor--on a bacterial spore. They call it NERD, for Nano-Electro-Robotic Device. The report is online at Scientific Reports, a Nature open access journal.

"We've taken a spore from a bacteria, and put graphene quantum dots on its surface--and then attached two electrodes on either side of the spore," said Vikas Berry, UIC associate professor of chemical engineering and principal investigator on the study.


"Then we change the humidity around the spore," he said. When the humidity drops, the spore shrinks as water is pushed out. As it shrinks, the quantum dots come closer together, increasing their conductivity, as measured by the electrodes. "We get a very clean response--a very sharp change the moment we change humidity," Berry said. The response was 10 times faster, he said, than a sensor made with the most advanced man-made water-absorbing polymers.


A sensitive and reproducible electron-tunneling width modulation of 1.63 nm within a network of GQDs chemically-secured on a spore was achieved via sporal hydraulics with a driving force of 299.75 Torrs (21.7% water at GQD junctions). The electron-transport activation energy and the Coulomb blockade threshold for the GQD network were 35 meV and 31 meV, respectively; while the inter-GQD capacitance increased by 1.12 folds at maximum hydraulic force.


This is the first example of nano/bio interfacing with spores and will lead to the evolution of next-generation bio-derived microarchitectures, probes for cellular/biochemical processes, biomicrorobotic-mechanisms, and membranes for micromechanical actuation.

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Engineers create chameleon-like artificial 'skin' that shifts color on demand

Engineers create chameleon-like artificial 'skin' that shifts color on demand | Amazing Science | Scoop.it
Borrowing a trick from nature, engineers from the University of California at Berkeley have created an incredibly thin, chameleon-like material that can be made to change color -- on demand -- by simply applying a minute amount of force.

This new material-of-many-colors offers intriguing possibilities for an entirely new class of display technologies, color-shifting camouflage, and sensors that can detect otherwise imperceptible defects in buildings, bridges, and aircraft.

"This is the first time anybody has made a flexible chameleon-like skin that can change color simply by flexing it," said Connie J. Chang-Hasnain, a member of the Berkeley team and co-author on a paper published today in Optica, The Optical Society's (OSA) new high-impact journal.

By precisely etching tiny features -- smaller than a wavelength of light -- onto a silicon film one thousand times thinner than a human hair, the researchers were able to select the range of colors the material would reflect, depending on how it was flexed and bent.


The colors we typically see in paints, fabrics, and other natural substances occur when white, broad spectrum light strikes their surfaces. The unique chemical composition of each surface then absorbs various bands, or wavelengths of light. Those that aren't absorbed are reflected back, with shorter wavelengths giving objects a blue hue and longer wavelengths appearing redder and the entire rainbow of possible combinations in between. Changing the color of a surface, such as the leaves on the trees in autumn, requires a change in chemical make-up.


Recently, engineers and scientists have been exploring another approach, one that would create designer colors without the use of chemical dyes and pigments. Rather than controlling the chemical composition of a material, it's possible to control the surface features on the tiniest of scales so they interact and reflect particular wavelengths of light. This type of "structural color" is much less common in nature, but is used by some butterflies and beetles to create a particularly iridescent display of color.


Controlling light with structures rather than traditional optics is not new. In astronomy, for example, evenly spaced slits known as diffraction gratings are routinely used to direct light and spread it into its component colors. Efforts to control color with this technique, however, have proved impractical because the optical losses are simply too great.


The authors of the Optica paper applied a similar principle, though with a radically different design, to achieve the color control they were looking for. In place of slits cut into a film they instead etched rows of ridges onto a single, thin layer of silicon. Rather than spreading the light into a complete rainbow, however, these ridges -- or bars -- reflect a very specific wavelength of light. By "tuning" the spaces between the bars, it's possible to select the specific color to be reflected. Unlike the slits in a diffraction grating, however, the silicon bars were extremely efficient and readily reflected the frequency of light they were tuned to.


Earlier efforts to develop a flexible, color shifting surface fell short on a number of fronts. Metallic surfaces, which are easy to etch, were inefficient, reflecting only a portion of the light they received. Other surfaces were too thick, limiting their applications, or too rigid, preventing them from being flexed with sufficient control.


The Berkeley researchers were able to overcome both these hurdles by forming their grating bars using a semiconductor layer of silicon approximately 120 nanometers thick. Its flexibility was imparted by embedding the silicon bars into a flexible layer of silicone. As the silicone was bent or flexed, the period of the grating spacings responded in kind.


The semiconductor material also allowed the team to create a skin that was incredibly thin, perfectly flat, and easy to manufacture with the desired surface properties. This produces materials that reflect precise and very pure colors and that are highly efficient, reflecting up to 83 percent of the incoming light.


Their initial design, subjected to a change in period of a mere 25 nanometers, created brilliant colors that could be shifted from green to yellow, orange, and red - across a 39-nanometer range of wavelengths. Future designs, the researchers believe, could cover a wider range of colors and reflect light with even greater efficiency.

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SageRave of Get Custom Content's curator insight, March 13, 2015 11:59 AM

Someday, clothing may adjust itself to match the wearer's accessories. What do you think?

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Perfect colors, captured with one ultra-thin nanotech lens

Perfect colors, captured with one ultra-thin nanotech lens | Amazing Science | Scoop.it

 Most lenses are, by definition, curved. After all, they are named for their resemblance to lentils, and a glass lens made flat is just a window with no special powers. But a new type of lens created at the Harvard School of Engineering and Applied Sciences(SEAS) turns conventional optics on its head.


A major leap forward from a prototype device demonstrated in 2012, it is an ultra-thin, completely flat optical component made of a glass substrate and tiny, light-concentrating silicon antennas. Light shining on it bends instantaneously, rather than gradually, while passing through. The bending effects can be designed in advance, by an algorithm, and fine-tuned to fit almost any purpose.


With this new invention described today in Science, the Harvard research team has overcome an inherent drawback of a wafer-thin lens: light at different wavelengths (i.e., colors) responds to the surface very differently. Until now, this phenomenon has prevented planar optics from being used with broadband light. Now, instead of treating all wavelengths equally, the researchers have devised a flat lens with antennas that compensate for the wavelength differences and produce a consistent effect—for example, deflecting three beams of different colors by the same angle, or focusing those colors on a single spot.


“What this now means is that complicated effects like color correction, which in a conventional optical system would require light to pass through several thick lenses in sequence, can be achieved in one extremely thin, miniaturized device,” said principal investigator Federico Capasso, the Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering at Harvard SEAS.

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Donald Schwartz's curator insight, February 20, 2015 11:19 AM

Less glass is good. I'm so excited, I just can't hide it. 

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New self-healing nanogel for drug delivery

New self-healing nanogel for drug delivery | Amazing Science | Scoop.it
Self-healing gel can be injected into the body and act as a long-term drug depot.


Scientists are interested in using gels to deliver drugs because they can be molded into specific shapes and designed to release their payload over a specified time period. However, current versions aren’t always practical because must be implanted surgically.


To help overcome that obstacle, MIT chemical engineers have designed a new type of self-healing hydrogel that could be injected through a syringe. Such gels, which can carry one or two drugs at a time, could be useful for treating cancer, macular degeneration, or heart disease, among other diseases, the researchers say.


The new gel consists of a mesh network made of two components: nanoparticles made of polymers entwined within strands of another polymer, such as cellulose. “Now you have a gel that can change shape when you apply stress to it, and then, importantly, it can re-heal when you relax those forces. That allows you to squeeze it through a syringe or a needle and get it into the body without surgery,” says Mark Tibbitt, a postdoc at MIT’s Koch Institute for Integrative Cancer Research and one of the lead authors of a paper describing the gel in Nature Communications on Feb. 19.


Scientists have previously constructed hydrogels for biomedical uses by forming irreversible chemical linkages between polymers. These gels, used to make soft contact lenses, among other applications, are tough and sturdy, but once they are formed their shape cannot easily be altered. The MIT team set out to create a gel that could survive strong mechanical forces, known as shear forces, and then reform itself. Other researchers have created such gels by engineering proteins that self-assemble into hydrogels, but this approach requires complex biochemical processes. The MIT team wanted to design something simpler. “We’re working with really simple materials,” Tibbitt says. “They don’t require any advanced chemical functionalization.”


The MIT approach relies on a combination of two readily available components. One is a type of nanoparticle formed of PEG-PLA copolymers, first developed in Langer’s lab decades ago and now commonly used to package and deliver drugs. To form a hydrogel, the researchers mixed these particles with a polymer — in this case, cellulose.


Each polymer chain forms weak bonds with many nanoparticles, producing a loosely woven lattice of polymers and nanoparticles. Because each attachment point is fairly weak, the bonds break apart under mechanical stress, such as when injected through a syringe. When the shear forces are over, the polymers and nanoparticles form new attachments with different partners, healing the gel.


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Stomach-acid-powered micromotors first-time tested in living animal

Stomach-acid-powered micromotors first-time tested in living animal | Amazing Science | Scoop.it

Imagine a micromotor fueled by stomach acid that can take a bubble-powered ride inside a mouse — and that could one day be a safer, more efficient way to deliver drugs or diagnose tumors for humans.

That’s the goal of a team of researchers at the University of California, San Diego. The experiment is the first to show that these micromotors can operate safely in a living animal, said Professors Joseph Wang and Liangfang Zhang of the NanoEngineering Department at the UC San Diego Jacobs School of Engineering.


Wang, Zhang and others have experimented with different designs and fuel systems for micromotors that can travel in water, blood and other body fluids in the lab. “But this is the first example of loading and releasing a cargo in vivo,” said Wang. “We thought it was the logical extension of the work we have done, to see if these motors might be able to swim in stomach acid.”


In the experiment, the mice ingested tiny drops of solution containing hundreds of the micromotors, which are 20 micrometers long. The motors become active as soon as they hit the stomach acid and zoom toward the stomach lining at a speed of 60 micrometers per second. They can self-propel like this for up to 10 minutes. This propulsive burst improved how well the cone-shaped motors were able to penetrate and stick in the mucous layer covering the stomach wall, explained Zhang. “It’s the motor that can punch into this viscous layer and stay there, which is an advantage over more passive delivery systems,” he said.


The researchers found that nearly four times as many zinc micromotors found their way into the stomach lining compared with platinum-based micromotors, which don’t react with and can’t be fueled by stomach acid.


The researchers explain that stomach acid reacts with the zinc body of the motors to generate a stream of hydrogen microbubbles that propel the motors forward. In their open-access study published in the journal ACS Nano, the researchers report that the motors lodged themselves firmly in the stomach lining of mice. As the zinc motors are dissolved by the acid, they disappear within a few days leaving no toxic chemical traces.


Wang said it may be possible to add navigation capabilities and other functions to the motors, to increase their targeting potential. Now that his team has demonstrated that the motors work in living animals, he noted, similar nanomachines soon may find a variety of applications including drug delivery, diagnostics, nanosurgery and biopsies of hard-to-reach tumors.

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Switching graphene nanoribbons from conductive to semiconducting

Switching graphene nanoribbons from conductive to semiconducting | Amazing Science | Scoop.it

Theoretical physicists at Rice University have figured out how to custom-design graphene nanoribbons by controlling the conditions under which the nanoribbons are pulled apart to get the edges they need for specific mechanical and electrical properties, such as metallic (for chip interconnects, for example) or semiconducting (for chips).


The new research by Rice physicist Boris Yakobson and his colleagues appeared this month in the Royal Society of Chemistry journal NanoscalePerfect (pristine) graphene is conductive and looks like chicken wire, with each six-atom unit forming a hexagon, with edges that are zigzags like this: /\/\/\/\/\/\/\/\ .


Turning the hexagons 30 degrees makes the edges “armchairs,” with flat tops and bottoms held together by the diagonals, making the nanoribbons both semiconducting and more stable.


The researchers used density functional theory, a computational method to analyze the energetic input of every atom in a model system, to learn how thermodynamic and mechanical forces would accomplish the goal.


Their study revealed that heating graphene to 1,000 kelvin and applying a low but steady force along one axis will crack it in such a way that fully reconstructed 5–7 rings will form and define the new edges. Conversely, fracturing graphene with low heat and high force is more likely to lead to pristine zigzags.

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DNA does design: 3D plasmonic photonic crystallization of DNA-guided colloidal crystals

DNA does design: 3D plasmonic photonic crystallization of DNA-guided colloidal crystals | Amazing Science | Scoop.it

As biotechnology and nanotechnology continue to merge, DNA-programmable methods have emerged as a way to provide unprecedented control over the assembly of nanoparticles into complex structures, including customizable periodic structures known as superlattices that allow fine tuning the interaction between light and highly organized collections of particles. Lattice structures have historically been two-dimensional because fabricating three-dimensional DNA lattices has been too difficult, while three-dimensional dielectric photonic crystals have well-established enhanced light–matter interactions. However, the dearth of synthetic means of creating plasmonic crystals (those that exploit surface plasmons produced from the interaction of light with metal-dielectric materials) based on arrays of nanoparticles has prevented them from being experimentally studied. At the same time, it has been suggested that polaritonic photonic crystals (PPCs) – plasmonic counterparts of photonic crystals – can prohibit light propagation and open a photonic band gap (also known as a polariton gap) by strong coupling between surface plasmons and photonic modes if the crystal is in a deep subwavelength size regime. Polaritons are quasiparticles resulting from strong coupling of electromagnetic waves with an electric or magnetic dipole-carrying excitation.


To that end, scientists at Northwestern University recently reported strong light-plasmon interactions within 3D plasmonic photonic crystals that have lattice constants and nanoparticle diameters that can be independently controlled in the deep subwavelength size regime by using a DNA-programmable assembly technique – the first devices prepared by DNA-guided colloidal crystallization. The researchers have shown that they can tune the interaction between light and the collective electronic modes of gold nanoparticles by independently adjusting lattice constants and gold nanoparticle diameters, adding that their results in tuning interactions between light and highly-organized nanoscale collections of particles suggest the possibility of applications that include lasers, quantum electrodynamics and biosensing.

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Super-insulated nano-clothing could eliminate need for indoor heating

Super-insulated nano-clothing could eliminate need for indoor heating | Amazing Science | Scoop.it

By wearing clothes that have been dip-coated in a silver nanowire (AgNW) solution that is highly radiation-insulating, a person may stay so warm in the winter that they can greatly reduce or even eliminate their need for heating their home. Considering that 47% of global energy is spent on indoor heating, and 42% of that specifically for residential heating, such highly insulating clothing could potentially have huge cost savings.


A team of researchers led by Professor Yi Cui, along with PhD student Po-Chun Hsu and others at Stanford University, have published a paper on the AgNW-coated textiles in a recent issue of Nano LettersAs the researchers explain, most strategies to reduce indoor heating focus on improving the insulation of the buildings, such as by using high R-value insulation and low-emissivity windows. However, a large portion of the energy is still wasted on heating empty space and inanimate objects.


To avoid this waste, the researchers have used a new strategy called "personal thermal management," which focuses on heating people. They've demonstrated that clothing dipped in a solution of metallic nanowires, such as AgNWs, achieves this goal by both providing passive insulation and allowing for active heating when connected to an external power source.


The main advantage of the AgNW-coated clothing is that it reflects over 90% of an individual's body heat (i.e., infrared radiation) back to the individual. This reflectance is much higher than even the warmest wool sweater, as the average clothing material reflects back only about 20% of body heat. This increase in reflectance is due to differences in the materials' emissivity, which is a measure of heat radiation.


Low-emissivity materials like silver, which has an emissivity of 0.02, emit less radiation and so provide much better insulation than high-emissivity materials like common textiles, which have an emissivity of about 0.8. Of course, wearing clothing made completely of silver would be impractical and uncomfortable, not to mention expensive. A main reason for this discomfort is that silver, like all metals, is not breathable. For example, Mylar blankets, which are made of aluminum and plastic, are extremely warm but are not vapor-permeable, causing moisture to accumulate on a person's skin.


The new AgNW-coated clothing, on the other hand, is breathable due to the nanowires' porous structure. The large spacing between nanowires of about 300 nm offers plenty of room for water vapor molecules, which are about 0.2 nm, to pass through. The 300-nm spacing is still much too small to allow body heat to pass through, since human body radiation has a wavelength of about 9 µm and so interacts with the nanowire cloth as if it were a continuous metal film, and is reflected.

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Tiny hinges and pistons hint at possible complexity of future nano-robots based on DNA origami

Tiny hinges and pistons hint at possible complexity of future nano-robots based on DNA origami | Amazing Science | Scoop.it

If the new nano-machines built at The Ohio State University look familiar, it’s because they were designed with full-size mechanical parts such as hinges and pistons in mind. The project is the first to prove that the same basic design principles that apply to typical full-size machine parts can also be applied to DNA—and can produce complex, controllable components for future nano-robots.


In a paper published this week in the Proceedings of the National Academy of Sciences, Ohio State mechanical engineers describe how they used a combination of natural and synthetic DNA in a process called “DNA origami” to build machines that can perform tasks repeatedly.


“Nature has produced incredibly complex molecular machines at the nanoscale, and a major goal of bio-nanotechnology is to reproduce their function synthetically,” said project leader Carlos Castro, assistant professor of mechanical and aerospace engineering. “Where most research groups approach this problem from a biomimetic standpoint—mimicking the structure of a biological system—we decided to tap into the well-established field of macroscopic machine design for inspiration.”


“In essence, we are using a bio-molecular system to mimic large-scale engineering systems to achieve the same goal of developing molecular machines,” he said.


Ultimately, the technology could create complex nano-robots to deliver medicine inside the body or perform nanoscale biological measurements, among many other applications. Like the fictional “Transformers,” a DNA origami machine could change shape for different tasks. “I’m pretty excited by this idea,” Castro said. “I do think we can ultimately build something like a Transformer system, though maybe not quite like in the movies. I think of it more as a nano-machine that can detect signals such as the binding of a biomolecule, process information based on those signals, and then respond accordingly—maybe by generating a force or changing shape."

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Francisco Rumiche's curator insight, February 6, 2015 7:38 PM

Carlos Castro, ingeniero mecánico y profesor en Ohio State University, ha desarrollado componentes en escala nano basándose en los mismos principios de diseño que aplican  para componentes de máquinas en escala macro.

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New Low-Cost Lithography Technique of Creating 3-D Nanostructures

New Low-Cost Lithography Technique of Creating 3-D Nanostructures | Amazing Science | Scoop.it

Researchers from North Carolina State University have developed a new lithography technique that uses nanoscale spheres to create three-dimensional (3-D) structures with biomedical, electronic and photonic applications. The new technique is significantly less expensive than conventional methods and does not rely on stacking two-dimensional (2-D) patterns to create 3-D structures.


“Our approach reduces the cost of nanolithography to the point where it could be done in your garage,” says Dr. Chih-Hao Chang, an assistant professor of mechanical and aerospace engineering at NC State and senior author of a paper on the work.


Most conventional lithography uses a variety of techniques to focus light on a photosensitive film to create 2-D patterns. These techniques rely on specialized lenses, electron beams or lasers – all of which are extremely expensive. Other conventional techniques use mechanical probes, which are also costly. To create 3-D structures, the 2-D patterns are essentially printed on top of each other. The NC State researchers took a different approach, placing nanoscale polystyrene spheres on the surface of the photosensitive film.


The nanospheres are transparent, but bend and scatter the light that passes through them in predictable ways according to the angle that the light takes when it hits the nanosphere. The researchers control the nanolithography by altering the size of the nanosphere, the duration of light exposures, and the angle, wavelength and polarization of light. The researchers can also use one beam of light, or multiple beams of light, allowing them to create a wide variety of nanostructure designs.


“We are using the nanosphere to shape the pattern of light, which gives us the ability to shape the resulting nanostructure in three dimensions without using the expensive equipment required by conventional techniques,” Chang says. “And it allows us to create 3-D structures all at once, without having to make layer after layer of 2-D patterns.”


The researchers have also shown that they can get the nanospheres to self-assemble in a regularly-spaced array, which in turn can be used to create a uniform pattern of 3-D nanostructures.


“This could be used to create an array of nanoneedles for use in drug delivery or other applications,” says Xu Zhang, a Ph.D. student in Chang’s lab and lead author of the paper.

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Wireless nanorod-nanotube film enables light stimulation of blind retina

Wireless nanorod-nanotube film enables light stimulation of blind retina | Amazing Science | Scoop.it

Scientists have developed a new light-sensitive film that could one day form the basis of a prosthetic retina to help people suffering from retinal damage or degeneration. Hebrew University of Jerusalem researchers collaborated with colleagues from Tel Aviv University and Newcastle University in the research, which was published in the journal Nano Letters.


The retina is a thin layer of tissue at the inner surface of the eye. Composed of light-sensitive nerve cells, it converts images to electrical impulses and sends them to the brain. Damage to the retina from macular degeneration, retinitis pigmentosa and other conditions can reduce vision or cause total blindness. In the United States alone, age-related macular degeneration (AMD) affects as many as 15 million Americans, with over 200,000 new cases diagnosed every year.


Scientists are currently designing a variety of medical devices to counter the effects of retinal disorders by sending visual signals to the brain. But these silicon-chip based solutions are typically hampered by their size, use of rigid parts, or requirement of external wiring such as to energy sources.


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Researchers create 3-D stereoscopic plasmonic color prints with nanopixels

Researchers create 3-D stereoscopic plasmonic color prints with nanopixels | Amazing Science | Scoop.it

By designing nanopixels that encode two sets of information—or colors of light—within the same pixel, researchers have developed a new method for making 3D color prints. Each pixel can exhibit one of two colors depending on the polarization of the light used to illuminate it. So by viewing the pixels under light of both polarizations, two separate images can be seen. If the two images are chosen to be slightly displaced views of the same scene, viewing both simultaneously results in depth perception and the impression of a 3D stereoscopic image.


The researchers, led by Professor Joel K.W. Yang, at A*STAR (the Agency for Science, Technology and Research) in Singapore, the National University of Singapore, and the Singapore University of Technology and Design, have published a paper on the new technique for realizing 3D full-color stereoscopic prints in a recent issue of Nature Communications.


"We have created possibly the smallest-ever stereoscopic images using pixels formed from plasmonic nanostructures," Yang told Phys.org. "Such stereoscopic images do not require the viewer to don special glasses, but instead, the depth perception and 3D effect is created simply by viewing the print through an optical microscope coupled with polarizers."


The work is based on the concept of surface plasmon resonance: metal nanostructures can scatter different wavelengths (colors) of light due to the fact that the tiny nanostructures themselves resonate at different wavelengths. If a nanostructure is circular, its resonance is polarization-independent because the diameter of the circle is the same from all directions. However, if a nanostructure is biaxial (such as an ellipse or rectangle), its resonance will depend on the polarization of the incident light. By tailoring the exact dimensions of the biaxial nanopixels, researchers can generate different colors under different polarizations.


Building on these ideas, the researchers in the current study have demonstrated that polarization-sensitive nanopixels that encode two sets of information can be used to produce 3D stereoscopic microprints. To do this, the researchers created nanopixels out of tiny pieces of aluminum a hundred or so nanometers across. Because these shapes are biaxial, they exhibit plasmonic resonances at different wavelengths for each axis, with the colors determined almost entirely by the dimension of the axis parallel to the polarization direction. For example, a 130-nm x 190-nm elliptical pixel appears green under y-polarized light and purple under x-polarized light. Comparing the two pixel shapes, the researchers found that the elliptical pixels have a broader range of polarization-dependent colors, while the nanosquare dimer pixels have lower levels of cross-talk, minimizing unwanted mixing of colors.

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Organic LEDs and carbon nanotubes may light up future fabrics

Organic LEDs and carbon nanotubes may light up future fabrics | Amazing Science | Scoop.it

With the emergence of wearable electronics that monitor fitness and health, there is a growing need for more flexible light-emitting devices. One option that researchers have been interested in is developing fabrics with integrated light-emitting devices. Unfortunately, fabrics themselves are not a suitable surface for current light-emitting materials. However, a team of scientists have found a way around this issue by integrating the light-emitting devices directly into fabrics using a new technology: light-emitting device fibers.


These research team, based in China, worked with polymer light-emitting electrochemical cells (PLECs). Like many other light-emitting devices, PLECs have a structure that is composed of two metal electrodes connected to a thin organic layer that acts as a semiconductor. Because PLECs have mobile ions incorporated into the semiconductor, they have many benefits compared to other light-emitting diodes (LEDs): low operating voltage, high efficiency in converting electrons to photons, and high power efficiency. PLECs are also a good option because they do not require the use of metals that are sensitive to air and they can be used on rougher surfaces; these characteristics make them suitable for large-scale manufacturing.


These fiber-shaped PLECs have a coaxial structure with four layers. Using a solution-based processing, a steel wire, which acts as the base of this fiber, is dip-coated with a thin layer of ZnO nanoparticles. This layer has two key functions: protecting the light-emitting layer that's applied next; and decreasing the leakage of the current, thus enhancing current efficiency.


Next, the electroluminescent polymer layer is deposited onto the wire using dip-coating. Finally, a sheet of aligned carbon nanotubes is wrapped around the bundle using a dry-drawn form of spinnable carbon nanotubes. Because the carbon nanotubes were highly aligned, they provided the fiber with high electrical conductivities. Imaging revealed that the fibers had a uniform diameter and a smooth outer surface.


The scientists who created these fibers determined the lifetime of the devices. They found that the fibers gradually light up over a 21-minute period and gradually dim over a four-hour period; in these studies, the light emitted by the fibers was blue. The fiber lit up when a voltage of 5.6V was applied and reached a peak intensity at 13V. When the fiber is pre-charged, it displays a rapid turn-on response that is similar to conventional LEDs.


The brightness of the light emitted by the fibers was almost entirely independent of viewing angle. When the fibers were bent, they maintained their brightness above 90 percent and no obvious damage was observed. Though only blue light was explored in these studies, the team believes other colors could be displayed as well.

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Quantum Dots Enable 3-D Printing of Contact Lenses With LEDs Embedded

Quantum Dots Enable 3-D Printing of Contact Lenses With LEDs Embedded | Amazing Science | Scoop.it

While the research may have only aimed to demonstrate what is possible for 3D printing of electronic devices, researchers at Princeton University have used 3D printing to create an entire contact lens with light-emitting diodes (LEDs) embedded into it.


For the contact lens to actually work, it would require an external energy source, making it impractical as a real-world device. However, the real point for the Princeton team was to show that it’s possible to produce electronic devices into complex shapes using equally complex materials.


"This shows that we can use 3D printing to create complex electronics including semiconductors," said Michael McAlpine, an assistant professor of mechanical and aerospace engineering, in a press release. "We were able to 3D print an entire device, in this case an LED."


The LED was made out of the somewhat exotic nanoparticles known as quantum dots. Quantum dots are a nanocrystal that have been fashioned out of semiconductor materials and possess distinct optoelectronic properties, most notably fluorescence, which makes them applicable in this case for the LEDs of the contact lens.


"We used the quantum dots [also known as nanoparticles] as an ink," McAlpine said. "We were able to generate two different colors, orange and green."


This latest work builds on the Princeton team’s previous work in producing a bionic ear using 3D printing. That research was aimed at demonstrating how electronics and biological materials could be merged using 3D printing.


In this latest research, which was published in the journal Nano Letters,  the aim was to show that active electronics could be printed using diverse materials.

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EmmanuelGrunenberger's curator insight, June 25, 2015 10:59 AM

LED lights embedded in your contact lens: convenient to read in the dark!

Although not worknig as no battery included, this achievement shows how nano technology will be included in every medical devices.

Next step: create a nano power supply using tears !

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New nanodevice defeats drug resistance and releases cancer drugs

New nanodevice defeats drug resistance and releases cancer drugs | Amazing Science | Scoop.it

Chemotherapy often shrinks tumors at first, but as cancer cells become resistant to drug treatment, tumors can grow back. A new nanodevice developed by MIT researchers can help overcome that by first blocking the gene that confers drug resistance, then launching a new chemotherapy attack against the disarmed tumors. The device, which consists of gold nanoparticles embedded in a hydrogel that can be injected or implanted at a tumor site, could also be used more broadly to disrupt any gene involved in cancer.


“You can target any genetic marker and deliver a drug, including those that don’t necessarily involve drug-resistance pathways. It’s a universal platform for dual therapy,” says Natalie Artzi, a research scientist at MIT’s Institute for Medical Engineering and Science (IMES), an assistant professor at Harvard Medical School, and senior author of a paper describing the device in the Proceedings of the National Academy of Sciences the week of March 2, 2015.


To demonstrate the effectiveness of the new approach, Artzi and colleagues tested it in mice implanted with a type of human breast tumor known as a triple negative tumor. Such tumors, which lack any of the three most common breast cancer markers — estrogen receptor, progesterone receptor, and Her2 — are usually very difficult to treat. Using the new device to block the gene for multidrug resistant protein 1 (MRP1) and then deliver the chemotherapy drug 5-fluorouracil, the researchers were able to shrink tumors by 90 percent in two weeks.


MRP1 is one of many genes that can help tumor cells become resistant to chemotherapy. MRP1 codes for a protein that acts as a pump, eliminating cancer drugs from tumor cells and rendering them ineffective. This pump acts on several drugs other than 5-fluorouracil, including the commonly used cancer drug doxorubicin. “Drug resistance is a huge hurdle in cancer therapy and the reason why chemotherapy, in many cases, is not very effective”, says João Conde, an IMES postdoc and lead author of the PNAS paper. To overcome this, the researchers created gold nanoparticles coated with strands of DNA complementary to the sequence of MRP1 messenger RNA — the snippet of genetic material that carries DNA’s instructions to the rest of the cell.


These strands of DNA, which the researchers call “nanobeacons,” fold back on themselves to form a closed hairpin structure. However, when the DNA encounters the correct mRNA sequence inside a cancer cell, it unfolds and binds to the mRNA, preventing it from generating more molecules of the MRP1 protein. As the DNA unfolds, it also releases molecules of 5-fluorouracil that were embedded in the strand. This drug then attacks the tumor cell’s DNA, since MRP1 is no longer around to pump it out of the cell. “When we silence the gene, the cell is no longer resistant to that drug, so we can deliver the drug that now regains its efficacy,” Conde says.

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Researchers Build Atomically-Thin Gas and Chemical Sensors

Researchers Build Atomically-Thin Gas and Chemical Sensors | Amazing Science | Scoop.it

The relatively recent discovery of graphene, a two-dimensional layered material with unusual and attractive electronic, optical and thermal properties, led scientists to search for other atomically thin materials with unique properties. Molybdenum disulfide (MoS2) has proved to be one of the most promising. Single-layer and few-layer molybdenum disulfide devices have been proposed for electronic, optoelectronic and energy applications. A team of researchers, led by engineers at the University of California, Riverside’s Bourns College of Engineering, have developed another potential application: sensors.


“The sensors are everywhere now, including in smart phones and other portable electronic devices,” said Alexander Balandin, UC Presidential Chair and professor of electrical and computer engineering at UC Riverside, who is the lead researcher on the project. “The sensors we developed are small, thin, highly sensitive and selective, making them potentially ideal for many applications.”


Balandin and the graduate students in his lab built the atomically thin gas and chemical vapor sensors from molybdenum disulfide and tested them in collaboration with researchers at the Rensselaer Polytechnic Institute in Troy, N.Y. The devices have two-dimensional channels, which are great for sensor applications because of the high surface-to-volume ratio and widely tunable concentration of electrons.


The researchers demonstrated that the sensors, which they call molybdenum disulfide thin-film field-effect transistors (TF-FET), can selectively detect ethanol, acetonitrile, toluene, chloroform and methanol vapors.


The findings were published in a recent paper, “Selective chemical vapor sensing with few-layer MoS2thin-film transistors: Comparison with graphene devices,” in the journal Applied Physics Letters.


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New Steel Alloy Is as Strong as Titanium, But Ten Times Cheaper

New Steel Alloy Is as Strong as Titanium, But Ten Times Cheaper | Amazing Science | Scoop.it

South Korean researchers have solved a longstanding problem that stopped them from creating ultra-strong, lightweight aluminum-steel alloys.

From shipping containers to skyscrapers to turbines, good old steel is still the workhorse of our modern world. Now, scientists are discovering new secrets to make the material better, lighter, and stronger.  


Today a team of material scientists at Pohang University of Science and Technology in South Korea announced what they're calling one of the biggest steel breakthroughs of the last few decades: an altogether new type of flexible, ultra-strong, lightweight steel. This new metal has a strength-to-weight ratio that matches even our best titanium alloys, but at one tenth the cost, and can be created on a small scale with machinery already used to make automotive-grade steel. The study appears in Nature.


"Because of its lightness, our steel may find many applications in automotive and aircraft manufacturing," says Hansoo Kim, the researcher that led the team. The key to creating this new super-steel was overcoming a challenge that had plagued materials scientists for decades. In the 1970's, Soviet researchers discovered that adding aluminum to the mix when creating steel can make an incredibly strong and lightweight metal, but this new steel was unavoidably brittle. You'd have to exert lots of force to reach the limit of its strength, but once you did, the steel would break rather than bend.


Scientists soon realized the problem: When creating the aluminum-steel alloy, they were occasionally fusing atoms of aluminum and iron together to form tough, crystalline structures called B2. These veins and nuggets of B2 were strong but brittle—until Kim and his colleges devised a solution. Kim and colleagues spent years devising and altering a method of heat-treating and then thinly rolling their steel to control when and where B2 crystals were formed. The team also discovered that adding a small percentage of nickel offered even more control over B2 formation, as nickel made the crystals form at a much higher temperature.

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Promising use of nanodiamonds to kill chemoresistant cancer stem cells more effectively

Promising use of nanodiamonds to kill chemoresistant cancer stem cells more effectively | Amazing Science | Scoop.it

A study led by the National University of Singapore (NUS) found that attaching chemotherapy drug Epirubicin to nanodiamonds effectively eliminates chemoresistant cancer stem cells. The findings were first published online in ACS Nano, the official journal of the American Chemical Society, in December 2014.


The research team, led by Assistant Professor Edward Chow, Junior Principal Investigator at the Cancer Science Institute of Singapore (CSI Singapore) at NUS, demonstrated the use of nanotechnology to repurpose existing chemotherapy drugs as effective agents against chemoresistant cancer stem cells. Chemoresistance, which is the ability of cancer cells to escape chemotherapy treatment, is a primary cause of treatment failure in cancer. Cancer stem cells, a type of cancer cell which initiates the formation of tumours, are commonly found to be more resistant to chemotherapy than the rest of the bulk tumour, which can lead to cancer recurrence following chemotherapy treatment. As such, there is intense interest in developing new drugs or treatment strategies that overcome chemoresistance, particularly in cancer stem cells.


In this study, widely-used chemotherapy drug Epirubicin was attached to nanodiamonds, carbon structures with a diameter of about five nanometres, to develop a nanodiamond-Epirubicin drug delivery complex (EPND). The researchers found that while both standard Epirubicin as well as EPND were capable of killing normal cancer cells, only EPND was capable of killing chemoresistant cancer stem cells and preventing secondary tumour formation in xenograft models of liver cancer.


Compared to other approaches such as combinatorial therapy of chemotherapy drugs with inhibitors of chemoresistance pathways, delivery of existing chemotherapy drugs with nanomaterials, in this case nanodiamonds, provide a broader range of protection in a package that is both safer and more effective. The study showed that delivery of Epirubicin by nanodiamonds resulted in a normally lethal dosage of Epirubicin becoming a safe and effective dosage. As such, delivery of chemotherapy drugs by nanodiamonds not only enables enhanced killing of chemoresistant cancer stem cells, but may be a useful alternative for patients who cannot tolerate the toxic side effects of standard chemotherapy drugs.


Furthermore, the versatility of the nanodiamond-based drug delivery platform opens up the possibility of future applications of nanodiamonds such as the addition of other similar drugs as well as active targeting components such as antibodies or peptides against tumour cell surface proteins for targeted drug release. In addition, the application of a nanodiamond-drug delivery system is not limited to liver cancer. It offers a promising approach to treating a broad range of difficult cancers, particularly those driven by chemoresistant cancer stem cells. In collaboration with Professor Dean Ho at the University of California Los Angeles and Professor Li Jianzhong at Peking University, Asst Prof Chow's group is working towards completing preclinical work on anthracycline delivery by nanodiamonds and hope to begin clinical trials in the near future.

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GLG Pharma's curator insight, February 6, 2015 7:54 AM

Cool new technology!

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Water-soluble silicon leads to dissolvable electronics

Water-soluble silicon leads to dissolvable electronics | Amazing Science | Scoop.it

Researchers working in a materials science lab are literally watching their work disappear before their eyes—but intentionally so. They're developing water-soluble integrated circuits that dissolve in water or biofluids in months, weeks, or even a few days. This technology, called transient electronics, could have applications for biomedical implants, zero-waste sensors, and many other semiconductor devices.

The researchers, led by John A. Rogers at the University of Illinois at Urbana-Champaign and Fiorenzo Omenetto at Tufts University, have published a study in a recent issue of Applied Physics Letters in which they analyzed the performance and dissolution times of various semiconductor materials.


The work builds on previous research, by the authors and others, which demonstrated that silicon—the most commonly used semiconductor material in today's electronic devices—can dissolve in water. Although it would take centuries to dissolve bulk silicon, thin layers of silicon can dissolve in more reasonable times at low but significant rates of 5-90 nm/day. The silicon dissolves due to hydrolysis, in which water and silicon react to form silicic acid. Silicic acid is environmentally and biologically benign.


In the new study, the researchers analyzed the dissolution characteristics of silicon dioxide and tungsten, which they used to fabricate two electronics devices: field-effect transistors and ring oscillators. Under biocompatible conditions (37 °C, 7.4 pH), dissolution rates ranged from 1 week for the tungsten components, to between 3 months and 3 years for the silicon dioxide components. The dissolution rates can be controlled by several factors, such as the thickness of the materials, the concentration and type of ions in the solution, and the method used to deposit the silicon dioxide on the original substrate.


As shown in the microscope images, the circuits do not dissolve in a uniform, layer-by-layer mode, but instead some places dissolve more rapidly than others. This is due to mechanical fractures in the fragile circuits, which cause the solution to penetrate through the layers more in some locations than in others. Although organic electronic materials are also often biodegradable, silicon-based electronics have the advantages of an overall higher performance and the use of complementary metal-oxide-semiconductor (CMOS) fabrication processes that allow for mass-production.

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‘Pop-up’ fabrication technique trumps 3D printing

‘Pop-up’ fabrication technique trumps 3D printing | Amazing Science | Scoop.it

3D silicon microstructures formed using concepts similar to those in children's pop-up books, shown here based on a colorized scanning electron micrograph.


Researchers at Northwestern University and the University of Illinois at Urbana-Champaign have developed a simple new fabrication technique to create beautiful, complex 3D micro- and nanostructures with advantages over 3D printing for a variety of uses. The technique mimics the action of a children’s pop-up book — starting as a flat two-dimensional structure and popping up into a more complex 3D structure. Using a variety of advanced materials, including silicon, the researchers produced more than 40 different geometric designs, including shapes resembling a peacock, flower, starburst, table, basket, tent, and starfish.


“In just one shot you get your structure,” said Northwestern’s Yonggang Huang, one of three co-corresponding authors on the study. “We first fabricate a two-dimensional structure on a stretched elastic material. Then we release the tension, and up pops a 3-D structure. The 2-D structure must have some place to go, so it pops up.”


The pop-up assembly technique is expected to be useful in building biomedical devices, sensors and electronics. It is the current cover story in the Jan. 9 issue of the journal Science.


References:


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Manipulating the "spin" of electrons on nanomagnets to create faster, more energy-efficient computers

Manipulating the "spin" of electrons on nanomagnets to create faster, more energy-efficient computers | Amazing Science | Scoop.it
Computers are basically machines that process information in the form of electronic zeros and ones. But two MIT professors of materials science and engineering are trying to change that.


Caroline Ross and Geoffrey Beach are members of the Center for Spintronic Materials, Interfaces, and Novel Architectures (C-SPIN), a University of Minnesota-led team of 32 professors (and over 100 graduate students and postdocs) from 18 universities trying to restructure computers from the bottom up. C-SPIN researchers want to use the "spin" of electrons on nanomagnets—rather than electric charge—to encode zeros and ones. If they are successful, the computers of 2025 could be 10 times faster than today's computers, while using only 1 percent of their energy.


Before C-SPIN began in 2013, spintronics research was carried out in many corners of American academia. The center, which is funded by a consortium of defense and industry sponsors, has helped researchers like Ross and Beach work directly on specified projects with colleagues around the country. "I appreciate the diverse group of students, faculty, and industrial researchers that C-SPIN brings together," says Ross. "I'm part of a work flow that includes researchers from Arizona, California-Riverside, Johns Hopkins, Carnegie Mellon, Minnesota, and Penn State. With the Center's coordinated funding, we are making significant progress."


Ross, the Toyota Professor of Materials Science and Engineering and associate head of the Department of Materials Science and Engineering, is developing methods to pattern ultra-small magnetic structures, and she is also working on magnetic "insulators" that help control the way "spin" is shared with neighboring magnets and other devices. One such magnetic structure is pictured at right.


Beach, the Class of '58 Associate Professor of Materials Science and Engineering, is investigating ways to reduce the power required to "switch" magnetic spin—that is, to make an "up" magnet "down," and vice versa. This process basically translates into changing zeros to ones and ones to zeros, something computers do billions of times per second. He recently discovered a new way to perform low-energy spin-switching (published in the prestigious Nature Materials and reported on here) which has led fellow C-SPIN researchers to develop new theoretical and experimental spin devices.

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'Glowing' dendrimers guide cancer surgery, also help killing remaining cancer cells

'Glowing' dendrimers guide cancer surgery, also help killing remaining cancer cells | Amazing Science | Scoop.it

Researchers at Oregon State University have developed a new way to selectively  insert compounds into cancer cells - a system that will help surgeons identify malignant tissues and then, in combination with phototherapy, kill any remaining cancer cells after a tumor is removed.

It’s about as simple as, “If it glows, cut it out.” And if a few malignant cells remain, they’ll soon die.


The findings, published in the journal Nanoscale, have shown remarkable success in laboratory animals. The concept should allow more accurate surgical removal of solid tumors at the same time it eradicates any remaining cancer cells. In laboratory tests, it completely prevented cancer recurrence after phototherapy.


Technology such as this, scientists said, may have a promising future in the identification and surgical removal of malignant tumors, as well as using near-infrared light therapies that can kill remaining cancer cells, both by mild heating of them and generating reactive oxygen species that can also kill them.


“This is kind of a double attack that could significantly improve the success of cancer surgeries,” said Oleh Taratula, an assistant professor in the OSU College of Pharmacy. “With this approach, cancerous cells and tumors will literally glow and fluoresce when exposed to near-infrared light, giving the surgeon a precise guide about what to remove,” Taratula said. “That same light will activate compounds in the cancer cells that will kill any malignant cells that remain. It’s an exciting new approach to help surgery succeed.”


The work is based on the use of a known compound called naphthalocyanine, which has some unusual properties when exposed to near-infrared light. It can make a cell glow as a guide to surgeons; heat the cell to kill it; and produce reactive oxygen species that can also kill it. And by adjusting the intensity of the light, the action of the compound can be controlled and optimized to kill just the tumor and cancer cells. This research was done with ovarian cancer cells.

However, naphthalocyanine isn’t water soluble and also tends to clump up, or aggregate, inside the body, in the process losing its ability to makes cells glow and generate reactive oxygen species. This also makes it difficult or impossible to find its way through the circulatory system and take up residence only in cancer cells.


OSU experts overcame these problems by use of a special water-soluble polymer, called a dendrimer, which allows the napthalocyanine to hide within a molecule that will attach specifically to cancer cells, and not healthy tissue. The dendrimer, an extremely tiny nanoparticle, takes advantage of certain physical characteristics that blood vessels leading to cancer cells have, but healthy ones do not. It will slip easily into a tumor but largely spare any healthy tissue.


Once in place, and exposed to the type of light needed, the cancer cells then will glow – creating a biological road map for a surgeon to follow in identifying what tissues to remove and what to leave. At the same time, a few minutes of this light exposure activate the naphthalocyanine to kill any remaining cells. This one-two punch of surgery and a nontoxic, combinatorial phototherapy holds significant promise, Taratula said. It’s quite different from existing chemotherapies and radiotherapies.

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MEMS sensors and platforms to build a hyper-attentive world of objects

MEMS sensors and platforms to build a hyper-attentive world of objects | Amazing Science | Scoop.it

Ever wonder how your smartphone got so smart? It stores pictures right-side up, knows where the North Star is, and always brings you home. This spatial acumen originates from micrometer-sized devices known as microelectromechanical systems (MEMS) that sense velocity, acceleration and magnetic field strength. Demand for MEMS has boomed recently, with MEMS sensors finding their way into satellites, cars, gaming consoles, cameras and, of course, mobile phones.


"MEMS technology is re-invigorating the somewhat stagnant semiconductor industry," says Alex Gu, director of the Sensors, Actuators and Microsystems Programme at the A*STAR Institute of Microelectronics (IME). "Produced using the same set of tools and processes as the conventional semiconductor industry, MEMS support the integration of multiple sensing functionalities onto a very small footprint at a very affordable price." MEMS facilitate the intercommunication of objects envisioned by 'the Internet of things', where light bulbs connect with smartphones and traffic lights with approaching vehicles.


Gu and colleagues at IME are realizing this vision through developing advanced MEMS devices that monitor the environment, harvest vibrational energy and keep time. They are also contributing to the three-dimensional consolidation of stand-alone MEMS devices onto one shared platform with integrated circuits, paving the way for large-scale deployment.


Gases such as carbon dioxide, hydrocarbons and ketones are critical indicators for environmental monitoring. They absorb light at specific wavelengths in the mid-infrared region. Optical detectors read the absorption signatures of gases in the atmosphere but are too bulky, expensive or specialized. Gu's team is developing a MEMS gas-sensing platform that is small enough to fit in a mobile phone and that can be tuned over a wide wavelength range, allowing it to monitor various gases associated with environmental and health risks. Sensor lifetimes, however, are limited by battery capacity—a common problem for wireless sensor nodes. To overcome this issue, MEMS vibration energy harvesters convert otherwise wasted ambient vibrational energy into usable electrical energy to sustain the sensors. IME researchers are expanding the frequency range of existing harvesters to double their efficiency.

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Amazing: Artist creates nanosculptures much smaller than a human hair

Amazing: Artist creates nanosculptures much smaller than a human hair | Amazing Science | Scoop.it

A sculpture so tiny that it cannot be seen by the naked eye is claimed to be the smallest sculpture of the human form ever created. Measuring a picayune 20 x 80 x 100 microns, artist Jonty Hurwitz’s tiny human statue is part of a new series of equally diminutive new sculptures that are at a scale so infinitesimally miniscule that each of the figures is approximately equal in size to the amount your fingernails grow in around about 6 hours, and can only be viewed using a scanning electron microscope.


Sculpted with an advanced new nano 3D printing technology coupled with a technique called multiphoton lithography, these works of art are created using a laser that uses the phenomenon of two photon absorption. In this way, an object is traced out by a laser in a block of light-sensitive monomer or polymer gel, and the excess is then washed away to leave a solid form.


As this method of two photon absorption only takes place at the tiny focal point of the laser, it essentially creates a tiny 3D pixel (a voxel) at that juncture. The laser is then moved along a fractional distance under computer control and the next voxel in the series is formed. In a long and painstaking process that takes place over many hours, the complete 3D sculpture is assembled voxel by voxel.


"We live in an era where the impossible has finally come to pass," said Hurwitz. "In our own little way we have become demi-gods of creation. Contemporary art, in my humble view, needs to reflect the human condition as it is today, it needs to represent the state of society at the time of its creation. Take a moment to consider that only 6,000 years ago we were painting crude animal images on the walls of caves with rocks. We have come far. This nano sculpture is the collective achievement of all of humanity. It is the culmination of thousands of years of R&D."

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