and more efficient including targeted nanoparticles. Wen Xue a senior postdoc at the Koch Institute is also a lead author of the paper.
The work was supported in part by the Army Research Office, through MIT Institute for Soldier Nanotechnologies,
and other substances including living cells MIT engineers have coaxed bacterial cells to produce biofilms that can incorporate nonliving materials such as gold nanoparticles and quantum dots.
These peptides can capture nonliving materials such as gold nanoparticles incorporating them into the biofilms. By programming cells to produce different types of curli fibers under certain conditions the researchers were able to control the biofilms properties
and create gold nanowires conducting biofilms and films studded with quantum dots or tiny crystals that exhibit quantum mechanical properties.
They also engineered the cells so they could communicate with each other and change the composition of the biofilm over time.
If gold nanoparticles are added to the environment the histidine tags will grab onto them creating rows of gold nanowires and a network that conducts electricity.
To add quantum dots to the curli fibers the researchers engineered cells that produce curli fibers
along with a different peptide tag called Spytag which binds to quantum dots that are coated with Spycatcher a protein that is Spytag s partner.
along with the bacteria that produce histidine-tagged fibers resulting in a material that contains both quantum dots and gold nanoparticles.
Now, a team of MIT researchers wants to make plants even more useful by augmenting them with nanomaterials that could enhance their energy production
In a new Nature Materials paper, the researchers report boosting plantsability to capture light energy by 30 percent by embedding carbon nanotubes in the chloroplast,
Using another type of carbon nanotube, they also modified plants to detect the gas nitric oxide. Together
these represent the first steps in launching a scientific field the researchers have dubbed lant nanobionics. lants are very attractive as a technology platform,
Supercharged photosynthesis The idea for nanobionic plants grew out of a project in Strano lab to build self-repairing solar cells modeled on plant cells.
the researchers embedded them with cerium oxide nanoparticles, also known as nanoceria. These particles are very strong antioxidants that scavenge oxygen radicals
the researchers also embedded semiconducting carbon nanotubes, coated in negatively charged DNA, into the chloroplasts. Plants typically make use of only about 10 percent of the sunlight available to them,
but carbon nanotubes could act as artificial antennae that allow chloroplasts to capture wavelengths of light not in their normal range, such as ultraviolet, green,
With carbon nanotubes appearing to act as a rosthetic photoabsorber photosynthetic activity measured by the rate of electron flow through the thylakoid membranes was 49 percent greater than that in isolated chloroplasts without embedded nanotubes.
When nanoceria and carbon nanotubes were delivered together, the chloroplasts remained active for a few extra hours. The researchers then turned to living plants
and used a technique called vascular infusion to deliver nanoparticles into Arabidopsis thaliana, a small flowering plant.
Using this method, the researchers applied a solution of nanoparticles to the underside of the leaf,
where it penetrated tiny pores known as stomata, which normally allow carbon dioxide to flow in and oxygen to flow out.
the nanotubes moved into the chloroplast and boosted photosynthetic electron flow by about 30 percent.
What is the impact of nanoparticles on the production of chemical fuels like glucose? Giraldo says.
Lean green machines The researchers also showed that they could turn Arabidopsis thaliana plants into chemical sensors by delivering carbon nanotubes that detect the gas nitric oxide,
Strano lab has developed previously carbon nanotube sensors for many different chemicals, including hydrogen peroxide, the explosive TNT, and the nerve gas sarin.
When the target molecule binds to a polymer wrapped around the nanotube, it alters the tube fluorescence. e could someday use these carbon nanotubes to make sensors that detect in real time, at the single-particle level,
free radicals or signaling molecules that are at very low-concentration and difficult to detect, Giraldo says. his is a marvelous demonstration of how nanotechnology can be coupled with synthetic biology to modify
and enhance the function of living organisms in this case, plants, says James Collins, a professor of biomedical engineering at Boston University who was involved not in the research. he authors nicely show that self-assembling nanoparticles can be used to enhance the photosynthetic capacity of plants,
as well as serve as plant-based biosensors and stress reducers. By adapting the sensors to different targets,
They are also working on incorporating electronic nanomaterials, such as graphene, into plants. ight now, almost no one is working in this emerging field,
and the chemical engineering nanotechnology community to work together in an area that has a large potential.
and Howard Hughes Medical Institute investigator Sangeeta Bhatia relies on nanoparticles that interact with tumor proteins called proteases each
The MIT nanoparticles are coated with peptides (short protein fragments) targeted by different MMPS. These particles congregate at tumor sites where MMPS cleave hundreds of peptides
With the current version of the technology patients would first receive an injection of the nanoparticles then urinate onto the paper test strip.
To make the process more convenient the researchers are now working on a nanoparticle formulation that could be implanted under the skin for longer-term monitoring.
scientists have tried targeting them to lymph nodes using nanoparticles to deliver them, or tagging them with antibodies specific to immune cells in the lymph nodes.
Additional help came from MIT Institute for Soldier Nanotechnologies. Ball specifically credits former technology transfer specialist Lisa Shaler-Clark as instrumental in taking the APA rom the lab bench to the field.
#Creating synthetic antibodies MIT chemical engineers have developed a novel way to generate nanoparticles that can recognize specific molecules, opening up a new approach to building durable sensors for many different compounds
To create these ynthetic antibodies, the researchers used carbon nanotubes hollow, nanometer-thick cylinders made of carbon that naturally fluoresce
when exposed to laser light. In the past, researchers have exploited this phenomenon to create sensors by coating the nanotubes with molecules,
such as natural antibodies, that bind to a particular target. When the target is encountered, the carbon nanotube fluorescence brightens
or dims. The MIT team found that they could create novel sensors by coating the nanotubes with specifically designed amphiphilic polymers polymers that are drawn to both oil and water, like soap.
This approach offers a huge array of recognition sites specific to different targets, and could be used to create sensors to monitor diseases such as cancer, inflammation,
or diabetes in living systems. his new technique gives us an unprecedented ability to recognize any target molecule by screening nanotube-polymer complexes to create synthetic analogs to antibody function,
which appears in the Nov 24 online edition of Nature Nanotechnology. Lead authors of the paper are recent Phd recipient Jingqing Zhang
Moreover, this approach can provide a more durable alternative to coating sensors such as carbon nanotubes with actual antibodies,
Their approach takes advantage of a phenomenon that occurs when certain types of polymers bind to a carbon nanotube.
when the polymers are exposed to carbon nanotubes, the hydrophobic regions latch onto the tubes like anchors
These loops form a new layer surrounding the nanotube, known as a corona. The MIT researchers found that the loops within the corona are arranged very precisely along the tube,
and alter the carbon nanotube fluorescence. Molecular interactions What is unique about this approach, the researchers say,
and the polymer before it attaches to the nanotube. he idea is that a chemist could not look at the polymer
It has to adsorb onto the nanotube and then, by having certain sections of the polymer exposed,
The researchers used an automated, robot-assisted trial and error procedure to test about 30 polymer-coated nanotubes against three dozen possible targets, yielding three hits.
They are now working on a way to predict such polymer-nanotube interactions based on the structure of the corona layers,
using data generated from a new type of microscope that Landry built to image the interactions between the carbon nanotube coronas
The research was funded by the National Science Foundation and the Army Research Office through MIT Institute for Soldier Nanotechnologies t
To decouple those two effects, the researchers coated the surface featuring spaced-out microscale posts with nanoscale particles.
under the same conditions, the droplets did not wet the surfaces of samples with either the microscale posts or the nanoscale texture,
Such particles could make it more feasible to design lab-on-a-chip devices, which hold potential as portable diagnostic devices for cancer and other diseases.
And the ground receiver is based on arrays of small inexpensive telescopes that are coupled fiber to highly efficient superconducting nanowires a photon counting technology that was brought to its high state of maturity by joint MIT and Lincoln Lab teams.
The noninvasive diagnostic described in a recent issue of the journal ACS Nano relies on nanoparticles that detect the presence of thrombin a key blood-clotting factor.
which is an injectable nanoparticle and made it a thrombin sensor. The system consists of iron oxide nanoparticles
which the Food and Drug Administration has approved for human use coated with peptides (short proteins) that are specialized to interact with thrombin.
After being injected into mice the nanoparticles travel throughout the body. When the particles encounter thrombin the thrombin cleaves the peptides at a specific location releasing fragments that are excreted then in the animals urine.
Through application of the nanoparticles if proven well-tolerated and nontoxic alterations in the normal low levels of physiological thrombin generation might be detected easily says Spronk who was not part of the research team.
Other applications for the nanoparticle system could include monitoring and diagnosing cancer. It could also be adapted to track liver pulmonary
Metal fatigue, for example which can result from an accumulation of nanoscale cracks over time s probably the most common failure modefor structural metals in general
For this study, the researchers found that light with a wavelength of 980 nanometers worked best.
Using this system, the researchers measured changes in the height of red blood cells, with nanoscale sensitivity,
The research was funded by the National Institute of Biomedical Imaging and Bioengineering and Nanoscope Technologies, LLC n
making the fibers thinner each time and approaching nanometer scale. During this process, Anikeeva says, eatures that used to be inches across are now microns.
the Center for Materials science and engineering, the Center for Sensorimotor Neural engineering, the Mcgovern Institute for Brain Research, the U s army Research Office through the Institute for Soldier Nanotechnologies,
The new findings using a layer of one-atom-thick graphene deposited on top of a similar 2-D layer of a material called hexagonal boron nitride (hbn) are published in the journal Nano Letters.
The hybrid material blocks light when a particular voltage is applied to the graphene, while allowing a special kind of emission and propagation,
Light interaction with graphene produces particles called plasmons while light interacting with hbn produces phonons.
The properties of the graphene allow precise control over light, while hbn provides very strong confinement and guidance of the light.
about 20 nanometers in size the same size range as the smallest features that can now be produced in microchips.
says, his work represents significant progress on understanding tunable interactions of light in graphene-hbn.
The work is retty criticalfor providing the understanding needed to develop optoelectronic or photonic devices based on graphene and hbn,
Now physicists at MIT have developed an experimental technique to simulate friction at the nanoscale. Using their technique,
Vladan Vuletic, the Lester Wolfe Professor of Physics at MIT, says the ability to tune friction would be helpful in developing nanomachines tiny robots built from components the size of single molecules.
Vuletic says that at the nanoscale, friction may exact a greater force for instance, creating wear and tear on tiny motors much faster than occurs at larger scales. here a big effort to understand friction and control it,
because it one of the limiting factors for nanomachines, but there has been relatively little progress in actually controlling friction at any scale,
Learn about the technique MIT physicists developed to simulate friction at the nanoscale. Video: Melanie Gonick/MIT (with computer simulations from Alexei Bylinkskii) Friction and force fieldsthe team simulated friction at the nanoscale by first engineering two surfaces to be placed in contact:
an optical lattice, and an ion crystal. The optical lattice was generated using two laser beams traveling in opposite directions,
not only for realizing nanomachines, but also for controlling proteins, molecules, and other biological components. n the biological domain, there are various molecules
from the nanoscale to the macroscale. he applications and related impact of their novel method propels a huge variety of research fields investigating effects relevant from raft tectonics down to biological systems
who was involved not in the research. ust imagine a nanomachine where we could control friction to enhance contact for traction,
EMS innovationsmicrochips Biotech made several innovations in the microelectromechanical systems (MEMS) manufacturing process to ensure the microchips could be commercialized.
The new approach uses yarns, made from nanowires of the element niobium, as the electrodes in tiny supercapacitors (which are essentially pairs of electrically conducting fibers with an insulator between).
Nanotechnology researchers have been working to increase the performance of supercapacitors for the past decade. Among nanomaterials, carbon-based nanoparticles such as carbon nanotubes and graphene have shown promising results,
but they suffer from relatively low electrical conductivity, Mirvakili says. In this new work, he and his colleagues have shown that desirable characteristics for such devices,
are not unique to carbon-based nanoparticles, and that niobium nanowire yarn is a promising an alternative. magine youe got some kind of wearable health-monitoring system,
Hunter says, nd it needs to broadcast data, for example using Wi-fi, over a long distance. At the moment, the coin-sized batteries used in many small electronic devices have limited very ability to deliver a lot of power at once,
The new nanowire-based supercapacitor exceeds the performance of existing batteries, while occupying a very small volume. f youe got an Apple Watch and
Other groups have made similar supercapacitors using carbon nanotubes or other materials, but the niobium yarns are stronger and 100 times more conductive.
Overall, niobium-based supercapacitors can store up to five times as much power in a given volume as carbon nanotube versions.
500 degrees Celsius so devices made from these nanowires could potentially be suitable for use in high-temperature applications.
individual niobium nanowires are just 140 nanometers in diameter 140 billionths of a meter across,
#New study shows how nanoparticles can clean up environmental pollutants Many human-made pollutants in the environment resist degradation through natural processes,
researchers from MIT and the Federal University of Goiás in Brazil demonstrate a novel method for using nanoparticles
They initially sought to develop nanoparticles that could be used to deliver drugs to cancer cells. Brandl had synthesized previously polymers that could be cleaved apart by exposure to UV light.
Nanoparticles made from these polymers have a hydrophobic core and a hydrophilic shell. Due to molecular-scale forces
in a solution hydrophobic pollutant molecules move toward the hydrophobic nanoparticles, and adsorb onto their surface,
If left alone, these nanomaterials would remain suspended and dispersed evenly in water. But when exposed to UV light,
according to the researchers, was confirming that small molecules do indeed adsorb passively onto the surface of nanoparticles. o the best of our knowledge,
it is the first time that the interactions of small molecules with preformed nanoparticles can be measured directly,
we showed in a system that the adsorption of small molecules on the surface of the nanoparticles can be used for extraction of any kind,
as another example of a persistent pollutant that could potentially be remediated using these nanomaterials. nd for analytical applications where you don need as much volume to purify or concentrate,
The study also suggests the broader potential for adapting nanoscale drug-delivery techniques developed for use in environmental remediation. hat we can apply some of the highly sophisticated,
and an expert in nanoengineering for health care and medical applications. hen you think about field deployment,
#Researchers use oxides to flip graphene conductivity Graphene a one-atom thick lattice of carbon atoms is touted often as a revolutionary material that will take the place of silicon at the heart of electronics.
By demonstrating a new way to change the amount of electrons that reside in a given region within a piece of graphene they have a proof-of-principle in making the fundamental building blocks of semiconductor devices using the 2-D material.
Moreover their method enables this value to be tuned through the application of an electric field meaning graphene circuit elements made in this way could one day be rewired dynamically without physically altering the device.
Chemically doping graphene to achieve p -and n-type version of the material is possible but it means sacrificing some of its unique electrical properties.
but manufacturing and placing the necessary electrodes negates the advantages graphene's form factor provides.
We've come up with a non-destructive reversible way of doping Rappe said that doesn't involve any physical changes to the graphene.
The team's technique involves depositing a layer of graphene so it rests on but doesn't bond to a second material:
Here we have graphene standing by on the surface of the oxide but not binding to it.
or gaining electrons the graphene says'I can hold the electrons for you and they'll be right nearby.'
Because the lithium niobate domains can dictate the properties Shim said different regions of graphene can take on different character depending on the nature of the domain underneath.
That allows as we have demonstrated a simple means of creating a p-n junction or even an array of p-n junctions on a single flake of graphene.
Such an ability should facilitate advances in graphene that might be analogous to what p-n junctions and complementary circuitry has done for the current state-of-the-art semiconductor electronics.
What's even more exciting are the enabling of optoelectronics using graphene and the possibility of waveguiding lensing and periodically manipulating electrons confined in an atomically thin material.
and the charge carrier density of the graphene suspended over it. And because the oxide polarization can be altered easily the type
and extent of supported graphene doping can be altered along with it. You could come along with a tip that produces a certain electric field
and the graphene's charge density would reflect that change. You could make the graphene over that region p-type
or n-type and if you change your mind you can erase it and start again.
Researchers make magnetic graphene More information: Nature Communications dx. doi. org/10.1038/ncomms713 3
#Researchers make magnetic graphene Graphene a one-atom thick sheet of carbon atoms arranged in a hexagonal lattice has many desirable properties.
Magnetism alas is not one of them. Magnetism can be induced in graphene by doping it with magnetic impurities
but this doping tends to disrupt graphene's electronic properties. Now a team of physicists at the University of California Riverside has found an ingenious way to induce magnetism in graphene while also preserving graphene's electronic properties.
They have accomplished this by bringing a graphene sheet very close to a magnetic insulator-an electrical insulator with magnetic properties.
This is the first time that graphene has been made magnetic this way said Jing Shi a professor of physics
and astronomy whose lab led the research. The magnetic graphene acquires new electronic properties so that new quantum phenomena can arise.
These properties can lead to new electronic devices that are more robust and multifunctional. The finding has the potential to increase graphene's use in computers as in computer chips that use electronic spin to store data.
Study results appeared online earlier this month in Physical Review Letters. The magnetic insulator Shi and his team used was yttrium iron garnet grown by laser molecular beam epitaxy in his lab. The researchers placed a single-layer graphene sheet on an atomically smooth layer of yttrium iron garnet.
They found that yttrium iron garnet magnetized the graphene sheet. In other words graphene simply borrows the magnetic properties from yttrium iron garnet.
Magnetic substances like iron tend to interfere with graphene's electrical conduction. The researchers avoided those substances
and chose yttrium iron garnet because they knew it worked as an electric insulator which meant that it would not disrupt graphene's electrical transport properties.
By not doping the graphene sheet but simply placing it on the layer of yttrium iron garnet they ensured that graphene's excellent electrical transport properties remained unchanged.
In their experiments Shi and his team exposed the graphene to an external magnetic field. They found that graphene's Hall voltage-a voltage in the perpendicular direction to the current flow-depended linearly on the magnetization of yttrium iron garnet (a phenomenon known as the anomalous Hall effect seen in magnetic materials like iron and cobalt.
This confirmed that their graphene sheet had turned magnetic. Explore further: Researchers find magnetic state of atoms on graphene sheet impacted by substrate it's grown on More information:
Physical Review Letters journals. aps. org/prl/abstract/#ysrevlett. 114.01660 6
#The latest fashion: Graphene edges can be tailor-made Theoretical physicists at Rice university are living on the edge as they study the astounding properties of graphene.
In a new study, they figure out how researchers can fracture graphene nanoribbons to get the edges they need for applications.
New research by Rice physicist Boris Yakobson and his colleagues shows it should be possible to control the edge properties of graphene nanoribbons by controlling the conditions under
which the nanoribbons are pulled apart. The way atoms line up along the edge of a ribbon of graphenehe atom-thick form of carbonontrols
whether it's metallic or semiconducting. Current passes through metallic graphene unhindered but semiconductors allow a measure of control over those electrons.
Since modern electronics are all about control, semiconducting graphene (and semiconducting two-dimensional materials in general) are of great interest to scientists
and industry working to shrink electronics for applications. In the work, which appeared this month in the Royal Society of Chemistry journal Nanoscale,
the Rice team used sophisticated computer modeling to show it's possible to rip nanoribbons
and get graphene with either pristine zigzag edges or what are called reconstructed zigzags. Perfect graphene looks like chicken wire,
with each six-atom unit forming a hexagon. The edges of pristine zigzags look like this://Turning the hexagons 30 degrees makes the edges"armchairs"
with flat tops and bottoms held together by the diagonals. The electronic properties of the edges are known to vary from metallic to semiconducting,
depending on the ribbon's width.""Reconstructed"refers to the process by which atoms in graphene are enticed to shift around to form connected rings of five and seven atoms.
The Rice calculations determined reconstructed zigzags are the most stable, a desirable quality for manufacturers.
All that is great, but one still has to know how to make them.""Making graphene-based nano devices by mechanical fracture sounds attractive,
but it wouldn't make sense until we know how to get the right types of edgesnd now we do said
Ziang Zhang, a Rice graduate student and the paper's lead author. Yakobson, Zhang and Rice postdoctoral researcher Alex Kutana 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 kelvins 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 z
#New technique helps probe performance of organic solar cell materials A research team led by North carolina State university has developed a new technique for determining the role that a material's structure has on the efficiency of organic solar cells
The researchers have used the technique to determine that materials with a highly organized structure at the nanoscale are not more efficient at creating free electrons than poorly organized structures#a finding
The researchers created highly organized nanostructures within a portion of the active layer of an organic solar cell meaning that the molecules in that portion all ran the same way.
and it tells us that we don't need highly ordered nanostructures for efficient free electron generation.
and nanostructure features are needed to advance organic solar cell technology. Explore further: Hybrid materials could smash the solar efficiency ceiling More information:
#Researchers generate tiny images that contain over 300 colors A scheme for greatly increasing the number of colors that can be produced by arrays of tiny aluminum nanodisks has been demonstrated by A*STAR scientists.
A similar effect can be realized at a much smaller scale by using arrays of metallic nanostructures since light of certain wavelengths excites collective oscillations of free electrons known as plasmon resonances in such structures.
An advantage of using metal nanostructures rather than inks is that it is possible to enhance the resolution of color images by a hundred fold.
Joel Yang and Shawn Tan at the A*STAR Institute of Materials Research and Engineering and co-workers used an electron beam to form arrays of approximately 100-nanometer-tall pillars.
In these arrays each pixel was an 800-nanometer-long square containing four aluminum nanodisks.
The plasmon resonance wavelength varies sensitively with the dimensions of the nanostructures. Consequently by varying the diameter of the four aluminum nanodisks in a pixel (all four nanodisks having the same diameter) the scientists were able to produce about 15 distinct colors#a good start
but hardly enough to faithfully reproduce full-color images. By allowing two pairs of diametrically opposite nanodisks to have different diameters from each other then varying the two diameters enabled them to increase this number to over 100.
Finally they generated over 300 colors by varying both the nanodisk diameter (but keeping all four diameters within a pixel the same) and the spacing between adjacent nanodisks in a pixel (see image).
This method is analogous to half-toning used in ink-based printing and results in a broad color gamut comments Yang.
The researchers demonstrated the effectiveness of their extended palette using a Monet painting. They reproduced the image using both a limited and extended palette with a much better color reproduction from the extended palette.
Researchers use aluminum nanostructures for photorealistic printing of plasmonic color palettes More information: Tan S. J. Zhang L. Zhu D. Goh X. M. Wang Y. M. et al.
Plasmonic color palettes for photorealistic printing with aluminum nanostructures. Nano Letters 14 4023#4029 (2014.
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