New avenue to etch semiconductors unleashed

MacEtch Process

Developing semiconductor structures for hardcore optoelectronic devices has always been a challenging job for professionals. In an attempt to make this job less troublesome, a team from the University of Illinois has created a way to chemically entrench sequenced arrays into the semiconductor gallium arsenide.

The aforesaid semiconductor is utilized in solar cells, LEDs, lasers, capacitors, sensors and FETs. Considering that III-V group substances are apparently difficult to dry etch and therefore get damaged easily, the team opted for a metal-assisted chemical etching process (MacEtch). It is a wet-etch method that was initially developed for silicon.

This method accessed a single direction from top to down unlike other wet techniques. It also seemed to be relatively swifter as compared to other dry etch avenues. In the research, the team conditioned the chemical solution and reaction states to work optimally for the III-V semiconductor gallium arsenide (GaAs).

This procedure can be done is 2 steps. Firstly, a slim layer of metal is carved on the GaAs surface after which the semiconductor with the metal pattern is dipped into the MacEtch chemical fluid. As the reaction is catalyzed by the metal, just the portions coming in contact with the metal are etched away. As the etching is done, the metal can be cleared off from the surface without any sort of damage.

“It is a big deal to be able to etch GaAs this way. The realization of high-aspect-ratio III-V nanostructure arrays by wet etching can potentially transform the fabrication of semiconductor lasers where surface grating is currently fabricated by dry etching, which is expensive and causes surface damage,” specified electrical and computer engineering professor Xiuling Li.

For generating metal film patterns, the team accessed a technique known as soft lithography. The team believed that the combo of MacEtch and soft lithiography could be an ideal way to synthesize greater area and high-aspect-ratio III-V nanostructures in a cost-friendly manner.

The research is published in the journal, Nano Letters.

Smallest 1 nanometer wide electrical motor unleashed: Research

Molecular Motor

There seems to be a new entrant in the Guinness World Records as the smallest electrical motor on the Earth. Tufts University researchers have apparently developed an electrical motor that is just 1 nanometer wide.

This could be the first stage of a new group of devices that ought to have medicinal as well as engineering applications. Single molecule motors are not entirely new, but either chemicals or light have been the driving forces. The scientists believe that such a motor fueled by electricity is far more beneficial than the others.

“The excitement is in the demonstration that you can provide electricity to a single molecule and get it to do something that’s not just random,” cited team leader Charles Sykes, an associate professor of chemistry in the School of Arts and Sciences.

This technology used scanning tunneling microscope which allows landing on the upper panel of a molecule that can then be measured and rotated suitably. Sykes and his team made use of the metal tip of the microscope to power the butyl methyl sulfide molecule that was kept on a copper surface. With a sulfur atom at the center, there were radiating carbon atoms that formed two arms. Precisely, four carbon atoms on one side and one on other end were used. Subsequently, such arms tend to play the role of gears, as one molecule is charged, it rolls and spins others in series.

However, Sykes warns that applications of the single-molecule electric motor for practical use are yet afar. But he hopes that it could be as medical test devices that constitute tiny pipes. They may also be used in nanoelectromechanical systems. In this experiment the analysts reduced the temperature around the molecular motor to minus 450 degrees F probably because as temperature increases, the motor turns speedily making it difficult for the investigators to note the rotations. Two different testers counted each set of rotations. This seemingly resulted in a double-blind process, to assure that the rotations were counted with accuracy. Sykes concluded that they will work more on this front and gauge the ways in which these molecular motors function.

The findings are reported in a paper published in Nature Nanotechnology on September 4.

‘Nanowire’ Memory Devices Enhance Computer Memory?

Silicon Nanowire Computers will be storing memory like never before, thanks to the following discovery. In a major breakthrough, researchers from the National Institute of Standards and Technology (NIST) have optimized nanowire-based charge-trapping memory devices that can lead to portable computers and cell phones which operate for days between charging sessions. These devices can supposedly improve computer memory.

The nascent technology is reportedly based on silicon formed into tiny wires, around 20 nanometers in diameter. These ‘nanowires’ probably form the basis of memory that is non-volatile holding its contents even while the power is off. This mechanism appears very much similar to the flash memory in USB thumb drives and many mp3 players. Such nanowire devices can apparently store information faster and at lower voltage.

“Cache memory stores the information a microprocessor is using for the task immediately at hand. It has to operate very quickly, and flash memory just isn’t fast enough. If we can find a fast, non-volatile form of memory to replace what chips currently use as cache memory, computing devices could gain even more freedom from power outlets—and we think we’ve found the best way to help silicon nanowires do the job,” commented NIST physicist Curt Richter.

These devices may be also capable of holding an additional advantage over flash memory, which despite its uses is unsuitable for one of the most crucial memory banks in a computer. During the research, scientists employed NIST’s talents at measurement to ascertain the best way of designing charge-trapping memory devices based on nanowires. These devices are supposedly surrounded by thin layers of material termed as dielectrics that store electrical charge.

Due to a combination of software modeling and electrical device characterization, the NIST and GMU team was presumably able to explore a wide range of structures for the dielectrics. The research findings purportedly create a platform for experimenters around the world to further investigate the nanowire-based approach to high-performance non-volatile memory.

Novel ‘Nanobed’ Approach Supposedly Improves Sensor Technology

Immunoassay Based Sensor

Magnetic ‘nanobeads’ now seem to have profound implications in several fields including bioterrorism, medical diagnostics, environmental monitoring or even water and food safety. Scientists from the Oregon State University have discovered a method to use magnetic ‘nanobeads’ for detecting chemical and biological agents in a number of applications. The research findings may revolutionize the size, speed and accuracy of chemical detection systems around the world.

Investigators believe that tapping into the capability of ferromagnetic iron oxide nanoparticles is the key to attain ‘microfluidic sensor.’ Using such particles in the new system can supposedly help identify chemicals with sensitivity and selectivity. They can also be reportedly incorporated into a system of integrated circuits to instantly display the findings. Hence, a powerful sensing technology which is fast, accurate, inexpensive, mass-producible, and small can be crafted.

“The particles we’re using are 1,000 times smaller than those now being used in common diagnostic tests, allowing a device to be portable and used in the field. Just as important, however, is that these nanoparticles are made of iron. Because of that, we can use magnetism and electronics to make them also function as a signaling device, to give us immediate access to the information available,” shared Vincent Remcho, an OSU professor of chemistry.

The present day assays appear not only cumbersome, but also time consuming. They probably employ biochemical probes that require expensive equipment, expert personnel or a complex laboratory to detect or interpret. The newly put forth approach, on the other hand, involves the attachment of tiny nanoparticles to these biochemical probes. Once a chemical of interest is detected, a ‘ferromagnetic resonance’ can be allegedly put to use for relaying the information electronically to a tiny computer. This data may be immediately viewed by users.

The new method does not require special thin films or complex processing, but the detection capability is still extremely sensitive and accurate. The system can possibly identify anything of interest in air or water. Rapid detection of chemical toxins such as anthrax, ricin or smallpox can be of great importance. The introduced concept can seemingly improve monitoring of commercial water treatment and supplies as well.

The research is published in the journal in Sensors and Actuators.

Nanotechnology Reportedly Keeps The Shine On Silver

Expert Ray Phaneuf Those polishing silver have always known that averting the tarnish seems impossible. Even the procedure of polishing is believed to rub away some of the precious metal. Well, it now appears that nanotechnology has come to the rescue for protecting the surface of silver. With a highly innovative approach, scientists have now crafted a protective coating which is so thin that it can’t be seen with the naked eye.

The method used to apply this coating may be termed as atomic layer deposition. With the help of this method, experts can seemingly govern over the thickness of the film at a sub-nanometer level itself. Nanometer thick films of aluminum oxide can be supposedly applied to a sample silver wafer through a special reactor inside a clean room. The films apparently conform to the recesses and protrusions of the silver, creating a protective barrier. However, those into art conservation presume that atomic layer deposition or ALD will undergo rigorous testing before they use it to protect irreplaceable treasures.

“Part of the challenge is to determine what the optimal thickness is that keeps sulfur off the silver surface. Eventually, thermodynamics tells us that the sulfur will diffuse through any layer we put down. The denser the layer, the slower the diffusion. So we’ll start with films that may be a few nanometers thick and investigate the efficacy of these films all the way out to maybe a few hundred nanometers. If we can increase the lifetime of these films to a century, you may not need to do this very often,” stated materials scientist Ray Phaneuf.

In the lab, the coating was subjected to a series of tests. Researchers employed a spectrometer to measure how light reflects off the surface of a test wafer and the way the ALD coating affects the wafer’s color. During the second test, the speed at which sulfur penetrates the coated wafer was gauged. It helped ascertain how many layers of coating will be needed to keep the silver shiny. In another controlled chamber, a coated wafer was heated to speed up the tarnishing.

The ALD not only protects silver, but also seemingly vaporizes the need for polishing.

Developed Nanowire Allegedly Sheds Light On New Devices

Electron Micrograph Just a few days back, researchers designed nanowires to enhance fuel cell efficiency and here is another investigation which adds to the benefits of this technology. Investigators from the Lund University in Sweden and the University of New South Wales have created a nanowire transistor that features a concentric metal ‘wrap-gate’ sitting horizontally on a silicon substrate. This unique nanowire transistor can supposedly help fabricate a number of vital devices in the near future.

Designed with utter simplicity, this nanowire transistor comes with an ability to tune the length of the wrap-gate via a single wet-etch step. Even the higher densities of transistors have been packed into a microchip to decrease overlap between the semiconductor channel through which the current flows and the metal gate makes it harder to switch the current on and off. This seemingly led to the development of the ‘Fin Field-Effect Transistor’, or FinFET. In this FinFET, the silicon either side of the channel is possibly etched away to produce a raised mesa structure.

So the gate to fold down around the sides of the channel attains a better control and improves the switching without increasing the chip space needed by the device. Getting metal underneath the channel without compromising the device appears as a formidable task using conventional ‘top-down’ silicon microfabrication techniques. These tiny semiconductor needles, around 50 nm in diameter are up to several microns in length. They are apparently grown by chemical vapour deposition and stand vertically on a semiconductor substrate.

Hence, Associate Professor Adam Micolich, an ARC Future Fellow in the Nanoelectronics Group in the UNSW School of Physics and colleagues were able to deposit an insulator and gate metal around the nanowire’s entire outer surface. These coated nanowires can be probably made into fully-functioning transistors in the vertical orientation. However, this may pose as an interesting challenge for nanotechnologists. During the research, experts demonstrated the first such horizontal wrap-gate nanowire transistors. They also highlighted that they can be made through a significantly simple process.

The research was published in NanoLetters.

New Nanowires Seemingly Improve Fuel Cell Efficiency

Bulk Metallic Glass Over the years, fuel cells have been considered as a cleaner solution to meet future energy needs. Well, the catalysts used even in today’s state-of-the-art fuels cells may break down, inhibiting the chemical reaction that converts fuel into electricity. In an attempt to boost the efficacy of fuel cells, a team of engineers from the Yale School of Engineering and Applied Science has now created a new fuel cell catalyst system through nanowires. The developed catalyst can probably improve long-term performance by 2.4 times in comparison to today’s technology.

Scientists have fabricated the miniscule nanowires by an innovative metal alloy known as a bulk metallic glass (BMG). Since, these nanowires have high surface areas, they may expose more of the catalyst and simultaneously maintain longer than traditional fuel cell catalyst systems. The present day fuel cell technology seemingly uses carbon black as a support for platinum particles. Carbon black appears as an inexpensive and electrically conductive carbon material transporting electricity, while the platinum is the catalyst that drives the production of electricity.

“This is the introduction of a new class of materials that can be used as electrocatalysts. It’s a real step toward making fuel cells commercially viable and, ultimately, supplementing or replacing batteries in electronic devices,” commented André Taylor.

Greater the number of platinum particles the fuel is exposed to, the more electricity is allegedly generated. However, a major drawback of this method is that carbon black seems to be porous, so the platinum inside the inner pores are not be exposed. In fact, carbon black is also believed to corrode over time. For producing more efficient fuel cells, the active surface area of the catalyst has to be probably elevated. At 13 nanometers in scale, the developed BMG nanowires were apparently three times smaller than carbon black particles.

The nanowires’ long, thin shape supposedly gives them much more active surface area per mass than carbon black. Instead of sticking platinum particles onto a support material, the platinum into the nanowire alloy reportedly ensures that it continues to react with the fuel over time. It’s the nanowires’ unique chemical composition that purportedly makes it possible to shape them into such small rods through a hot-press method. As of now, the catalyst system has been tested for alcohol-based fuel cells, such as those using ethanol and methanol as fuel sources.

The research appears in the April issue of ACS Nano.

Ultra Fast Means To Make Photodetectors Out Of Carbon Nanotubes Apparently Found

Carbon Nanotubes Carbon nanotubes may play a crucial role while developing optoelectronic components. As of now no electronic methods were probably turned fruitful to analyze the ultra fast optoelectronic dynamics of the nanotubes. A team of physicists has now laid hands on a novel method to directly measure the dynamics of photo-excited electrons in nanoscale photodetectors.

It is believed that carbon nanotubes contain a multitude of unusual properties which empowers them to play a key role in building optoelectronic components. During the research, scientists seemingly developed a measurement method allowing a time-based resolution of the so-called photocurrent in photodetectors with picosecond precision. The unique measurement technique appears around a hundred times faster than traditional methods. In the carbon nanotubes the electrons seemingly cover a distance of around 8 ten-thousandths of a millimeter or 800 nanometers in one picosecond.

“A picosecond is a very small time interval,” commented Alexander Holleitner. “If electrons traveled at the speed of light, they would make it almost all the way to the moon in one second. In a picosecond they would only cover about a third of a millimeter.”

The speed of the electrons was measured by a time-resolved laser spectroscopy process which is termed as the pump-probe technique. This technique supposedly excites electrons in the carbon nanotube by a laser pulse and analyzing the dynamics of the process through a second laser. The research findings may offer insights and analytic opportunities to a whole range of applications, including nanoscale photodetectors, photo-switches and solar cells.

The research was funded by the German Research Foundation (Cluster of Excellence Nanosystems Initiative Munich, NIM) and the Center for NanoScience (CeNS) at Ludwig-Maximilians-Universitaet Muenchen.

Novel Nanomaterials Presumably Enhance Next-Generation Electronic Devices

Telluride Nanoribbon Topological insulators acting as insulators as well as conductors apparently restrict the flow of electrical currents and allow the movement of a charge. The surfaces of topological insulators supposedly enable the transport of spin-polarized electrons while preventing the ‘scattering’ typically linked with power consumption. In a major breakthrough, scientists found a possibility to govern over the surface states of topological insulator nanoribbons made from bismuth telluride.

The surface states of the topological insulator nanoribbons appear ‘tunable,’ so they can be turned on and off depending on the position of the Fermi level. Employment of these topological insulators may aid in crafting new-generation, low-dissipation nanoelectronic and spintronic devices, from magnetic sensing to storage. Bismuth telluride commonly referred to as a thermoelectric material is presumed to be a three-dimensional topological insulator with robust and unique surface states.

“We have demonstrated a clear surface conduction by partially removing the bulk conduction using an external electric field,” said Faxian Xiu, a UCLA staff research associate and lead author of the study. “By properly tuning the gate voltage, very high surface conduction was achieved, up to 51 percent, which represents the highest values in topological insulators.”

Tests conducted with bismuth telluride bulk materials assert that two-dimensional conduction channels originate from the surface states. However, altering surface conduction is apparently not easy because of impurities and thermal excitations in such small–band-gap semiconductors. The large surface-to-volume ratios of these topological insulator nanoribbons possibly improve surface conditions and allow surface manipulation by external means.

“This research is very exciting because of the possibility to build nanodevices with a novel operating principle,” added Kang L. Wang, the Raytheon Professor of Electrical Engineering at UCLA Engineering, whose team carried out the research. “Very similar to the development of graphene, the topological insulators could be made into high-speed transistors and ultra–high-sensitivity sensors.”

During the research, scientists used thin bismuth telluride nanoribbons as conducting channels in field-effect transistor structures. These probably depend on an electric field to regulate both the Fermi level and the conductivity of a channel. On completion of the research, experts claimed to have successfully controlled the surface states in topological insulator nanostructures. The findings may result in a dramatic progress toward high surface electric conditions for practical device applications.

The research was published in Nature Nanotechnology.

Nanoscoops Can Supposedly Improve Electric Automobile Batteries

Novel Nanomaterial Batteries for electric automobiles may by the need of the hour due constant advancement in technology. High-power rechargeable lithium (Li)-ion batteries are in the making due to a unique type of nanomaterial designed by the Rensselaer Polytechnic Institute. These batteries appear beneficial in electric automobiles, as well as batteries for laptop computers, mobile phones, and other portable devices.

The newly developed material is termed as ‘nanoscoop’ because its shape resembles a cone with a scoop of ice cream on top. It can probably endure extremely high rates of charge and discharge that can trigger conventional electrodes used in today’s Li-ion batteries to rapidly deteriorate and fail. The nanoscoop apparently contains a unique material composition, structure, and size. Researchers show the way a nanoscoop electrode can be charged and discharged at a rate 40 to 60 times faster than conventional battery anodes. However, throughout the process a comparable energy density is allegedly maintained.

Nikhil Koratkar a professor in the Department of Mechanical, Aerospace, and Nuclear Engineering at Rensselaer, added, “Charging my laptop or cell phone in a few minutes, rather than an hour, sounds pretty good to me. By using our nanoscoops as the anode architecture for Li-ion rechargeable batteries, this is a very real prospect. Moreover, this technology could potentially be ramped up to suit the demanding needs of batteries for electric automobiles.”

This stellar performance can be probably attained by over 100 continuous charge/discharge cycles. The crafted technology may have greater significance for the design and realization of high-power, high-capacity Li-ion rechargeable batteries. Batteries for all-electric vehicles have to be supposedly delivering high power density along with abundant energy densities. Currently super capacitors are presumably employed in vehicles for gaining power-intensive functions, including starting the vehicle and rapid acceleration, in conjunction with conventional batteries that deliver high energy density for normal cruise driving and other operations. Nanoscoops reportedly enable these two separate systems to be combined into a single, more efficient battery unit.

Koratkar, explained, “Due to their nanoscale size, our nanoscoops can soak and release Li at high rates far more effectively than the macroscale anodes used in today’s Li-ion batteries. This means our nanoscoop may be the solution to a critical problem facing auto companies and other battery manufacturers – how can you increase the power density of a battery while still keeping the energy density high?”

Scientists claim that the anode structure of a Li-ion battery grows and shrinks physically as the battery charges or discharges. On charging, the addition of Li-ions may elevate the volume of the anode and while discharging develops the opposite effect. Hence, majority of the present day batteries in portable electronic devices such as handsets and laptops charge very slowly. The slow charge rate is probably intentional for guarding the battery from stress-induced damage. The built up nanoscoop is capable of withstanding this stress and quickly accept as well as discharge Li-ions. The technology has a carbon (C) nanorod base along with a thin layer of nanoscale aluminum (Al) and a ‘scoop’ of nanoscale silicon (Si).

The research is published in the journal Nano Letters.

Nanotechnology Helps Develop Highly Ordered Artificial Spin Ice

Spin Technology While nanotechnology has taken man to a completely different level, unique discoveries in the field of science continue taking place. Experts from the University of Leeds, the US Department of Energy’s Brookhaven National Laboratory and the UK Science and Technology Facilities Council’s Rutherford Appleton Laboratory have crafted an artificial spin ice in a state of thermal equilibrium with the help of nanotechnology. This technology probably assists in understanding the exact configuration of the nanomaterial.

The artificial spin ice may allow scientists to analyze them in much greater detail, which is commonly termed as ‘magnetic monopoles’. It is assumed that magnetic monopoles are present in such structures. Researchers built the artificial spin ice with millions of tiny magnets and each is thousand times smaller than a grain of sand. A lattice known as a ‘frustrated’ structure apparently holds these magnets. It is presumed that all interactions between the atoms cannot be satisfied at the same time. In spin ice, magnetic dipoles with a north and south pole are probably arranged within tetrahedron structures. The dipoles supposedly arrange themselves into the lowest possible energy state, that is two poles pointing in and two pointing out. Every dipole seems to have magnetic moments, just like protons on H2O molecules in water ice, which attract and repel each other.

Dr. Christopher Marrows from the University of Leeds, commented, “Spin ices have created a lot of excitement in recent years as it has been realized that they are a playground for physicists studying magnetic monopole excitations and Dirac string physics in the solid state. However, until now all of the samples of these artificial structures created in the lab have been what we call ‘jammed’. What we have done is find a way to un-jam spin ice and get it into a well-ordered ground state known as thermal equilibrium. We can then freeze a sample into this state, and use a microscope to see which way all the little magnets are pointing. It’s the equivalent of being able take a picture of every atom in a room as it allows us to inspect exactly how the structure is configured.”

While inspecting the sample using magnetic force microscopy, investigators seemingly observed individual excitations pointing out monopole dynamics within the lattice. Magnetic monopoles are known to be hypothetical particles that appear to exist in spin ice. It is anticipated that understanding these monopoles in more detail can pave way for further advances within a novel technology field known as ‘magnetricity.’ In order to witness dynamically excitations from ground state itself, experts possibly have to regulate the interactions with state of the art lithographic techniques.

The research was published in the journal Nature Physics.

MIT Scientists Develop Self-Healing Solar Cells

Solar Cell While using solar cell, a device known to convert energy obtained from sunlight into electricity, harvesting sunlight seems to be a major issue. As many a times, the sun’s rays may end up being highly destructive to other materials. With inspiration from nature, MIT experts have developed a solar material that promises to tackle this problem.

Scientists noticed that when sunlight tends to be destructive, plants begin to continuously break down their light-capturing molecules and regroup them from the very beginning. This process probably enables plants to safeguard the basic structures from the sun’s energy. The experts aimed at mimicking this process adopted by plants. For this they developed a unique set of self-assembling molecules that can convert sunlight into electricity. It was elucidated that the molecules can be frequently broken down and then reassembled immediately, by simply adding or removing an additional solution.

The process is known to take place in minute capsules known as chloroplasts that are present inside every plant cell. Even photosynthesis in plants takes place in chloroplasts itself. While imitating the process, experts produced synthetic molecules called phospholipids that form disks. These disks seemingly give structural support to other molecules which respond to light, in structures termed as reaction centers known to release electrons when struck by particles of light.

Reaction center holding disks are in a solution where they immediately attach themselves to carbon nanotubes. These nanotubes are wire-like hollow tubes of carbon atoms that are a few billionths of a meter thick. It has been claimed that these tubes are stronger than steel and conduct electricity in a more efficient manner as compared to copper. In order to expose all the reaction centers to sunlight at once, the nanotubes hold the phospholipid disks in a uniform alignment. These nanotubes also acting as wires accumulate and guide the flow of electrons knocked loose by the reactive molecules.

Seven different compounds are encompassed in the newly developed system, including carbon nanotubes, phospholipids, and proteins that make up reaction centers. These proteins instinctively gather themselves into a light-harvesting structure that generates an electric current under the right conditions. In the course of investigation, researchers ran the cell through repeated cycles of assembly and disassembly over a 14-hour period, with no loss of efficiency. Currently investigators are finding means to elevate the concentration of structures.

The paper was published in Nature Chemistry on September 5.

Nanosize Biological RNA Particles Might Help Fight Cancer

Nanosize Biologoical RNA

Previously, we had reported on researchers who supposedly found the cell of origin for prostate cancer. Two new papers based on researches conducted by scientists from UC Santa Barbara saw scientists displaying the potential of a synthesis of nanosize biological particles to combat cancer and other diseases. These papers elucidated the new approaches, which were considered as green nanobiotechnology, since they did not make use of any artificial compounds.

Luc Jaeger is an associate professor of chemistry and biochemistry at UCSB. He stated that the revolution going on his field in the area of nanobiotechnology, pertained to understanding the role played by RNA present in our cells. The team piloted by Jaeger attempts to synthesize complex three-dimensional RNA molecules, which are nanosize polyhedrons that may have the ability to fight diseases. These molecules are known to self assemble to form new shapes.

“Considering the fact that up to 90 percent of the human genome is transcribed into RNA, it becomes clear that RNA is one of the most important biopolymers on which life is based,” said Jaeger. “We are still far from understanding all the tremendous implications of RNA in living cells. We are interested in using RNA assemblies to deliver silencing RNAs and therapeutic RNA aptamers to target cancer and other diseases. It is clear that RNA is involved in a huge number of key processes that are related to health issues.”

Moreover, Jaeger proposes that using RNA-based approaches to offer new therapies to the body could be safer than artificial compounds, as these might have negative side effects later on. He states that by making use of RNA molecules, the researchers will be utilizing green nanobiotechnology.

Recently, a paper entitled the ‘In vitro assembly of cubic RNA-based scaffolds designed in silicon’ was published online on August 30 by Nature Nanotechnology. The other one was published by Severcan and his associates earlier on July 18. Titled ‘A polyhedron made of tRNAs’, the paper went online through Nature Chemistry, whereas its print edition will appear in Nature Chemistry’s September issue.

Faster Production Of Microalgae Could Help In Creating Biofuels

AlgaeDue to the depletion in the source of non-renewable resources, scientists and researchers world over have begun finding new means of producing fuel. These biofuels need to be efficient, economically producible and ecological sustainable to be feasible for practical usage. Radhakrishna Sureshkumar and Satvik Wani have discovered a method through which it might be easy to create a biofuel which accomplishes the above three targets.

Sureshkumar and Wani have developed a process of producing microalgae faster by influencing the number of light particles with the help of nanotechnology. Algae can be used for the production of biofuels. With this accelerated photosynthesis, the algae is said to generate faster, without affecting the ecological resources. This has been found by Syracuse University’s Radhakrishna Sureshkumar, professor and chair of biomedical and chemical engineering in the L.C. Smith College of Engineering and Computer Science. Along with an SU chemical engineering Ph.D. student, named Satvik Wani.

“Algae produce triglycerides, which consist of fatty acids and glycerin. The fatty acids can be turned into biodiesel while the glycerin is a valuable byproduct,” commented Sureshkumar. “Molecular biologists are actively seeking ways to engineer optimal algae strains for biofuel production. Enhancing the phototropic growth rate of such optimal organisms translates to increased productivity in harvesting the feedstock.”

They have invented a bioreactor, which is capable of increasing the growth of algae. This was done with the help of nanoparticles, which selectively scatter blue light as a result of which it augments the algae metabolism. On using the ideal combination of light and confined nanoparticle suspension configuration, the growth enhancement resulted to an algae sample, which was found to be 30 percent higher than what could be procured in control.

This mini bioreactor was created by taking a petri dish which held a strain of green algae scientifically known as Chlamydomonas reinhardtii. On top of this dish was another consisting of a suspension of silver nanoparticles, which back scattered the blue light into the algae culture. By varying the size and concentration of the nanoparticle solution, the team found that the frequency and intensity of the light source could be manipulated. Hence, they were able to procure a favorable wavelength for algal growth.

“Implementation of easily tunable wavelength specific backscattering on larger scales still remains a challenge, but its realization will have a substantial impact on the efficient harvesting of phototrophic microorganisms and reducing parasitic growth,” elucidated Sureshkumar. “Devices that can convert light not utilized by the algae into the useful blue spectral regime can also be envisioned.”

This discovery is claimed to be one of the foremost which makes use of nanobiotechnology to uphold microalgal growth. It not only has benefits in the field of biofuel production but also outside it. In the future Sureshkumar and Wani will attempt using these findings to make environmental sensors which can be used for ecological warning systems.

This process has been explained in the August 2010 issue of Nature Magazine.

NIST Crafts Multi-Tool To Seperate Nanoparticles

Nanofluidic Graph

A tool box may be equipped with multi-purpose instruments but their use is restricted to repairing or creating objects that are relatively simpler than nanoparticles. The research team at NIST has surfaced with a miniature multi-tool which is a nanoscale fluidic equipment engineered for working with nanoparticles.

The team first crafted a 3D nanofluidic staircase channel with many depths to separate and calculate a mixture of different-sized fluorescent nanoparticles. The particles that were larger were brighter than the small, dim ones. These particles were then pushed towards the shallow side of the channel which then stopped at the steps of the staircase according to their sizes.

The device is made up of cascading staircase of 30 nanofluidic channels that range from about 80 nanometers at the top to about 620 nanometers at the bottom in depth. Each of these steps functions as a tool of a different size to maneuver nanoparticles. The study shows that the device can carry out nanoscale tasks of separating and measuring a mixture of spherical nanoparticles differing in size and dispersed in a solution.

The team employed electrophoresis to move the charged particles through a solution by pushing them ahead with an applied electric field. This drives the nanoparticles present in the deep end of the chamber across the device into the shallower channels. Additionally, the nanoparticles were assigned fluorescent colors to track them through a microscope.

It was noted that the larger particles stopped on reaching the steps of the staircase with depths that matched their diameters of around 220 nanometers. The smaller particles kept moving till they were restricted from entering shallower channels at depths of around 110 nanometers.

The position of every particle could be mapped to the corresponding channel depth thanks to their fluorescent points of light. The researchers could then gauge the distribution of nanoparticle sizes and assert the utility of the device as a separation tool and reference material. This method would make it easier to separate intricate mixtures when integrated in a microchip.

The researchers believe that this method could be faster and more economical as opposed to conventional methods of nanoparticle sample preparation and characterization. The team plans to design nanofluidic devices for different nanoparticle sorting applications. These devices could be crafted with customized resolution over a particular range of particle sizes and for select materials. Moreover, the team aims to invent a technique to separate mixtures of nanoparticles with similar sizes but different shapes.

The study has been mentioned in a new article in the journal Lab on a Chip.