Electrostatic Force Microscopy (EFM): Imaging electric charge using microbial nanowires: Breakthrough in protein based nanoelectronics

Recent study carried out by UMass Amherst researchers has showed that electric charges propagate along microbial nanowires of the microbe Geobacter just as they do in carbon nanotubes.

Physicists affirmed that injection of electrons at one end in the microbial nanowires lit up the whole filament as the electrons propagated through the nanowire, similar to the other highly conductive materials. The technique applied here is known as electrostatic force microscopy (EFM). This technique has immense environment implications as conversion of waste to biogas is possible by conducting electricity through these wires. The nanowires permit Geobacter to live on iron and other metals in the soil, significantly changing soil chemistry and playing an important role in environmental cleanup. Microbial nanowires are also key components in the ability of Geobacter to produce electricity, a novel capability that is being adapted to engineer microbial sensors and biological computing devices.

In biological materials, electrons typically move by hopping along discrete biochemical stepping-stones that can hold the individual electrons. By contrast, electrons in microbial nanowires are delocalized, not associated with just one molecule, leading to metallic-like conductivity phenomena.

This investigation not only brings up an important new principle in biology but also in materials science. Natural amino acids, when arranged correctly, can propagate charges similar to molecular conductors. It opens exciting opportunities for protein-based nanoelectronics due to the fact that manipulating microbes for electrical application seems feasible. Efforts are also directed towards building electronic sensors to detect environmental contaminants and microbiological computers using Geobacter.

Manipulation of Cells and molecules by biomolecular mechanical tweezers

A new type of biomolecular tweezers could help researchers to study how mechanical forces affect the biochemical activity of cells and proteins. The devices, too small to see without a microscope, use opposing magnetic and electrophoretic forces to precisely stretch the cells and molecules, holding them in position so that the activity of receptors and other biochemical activity can be studied.

Arrays of the tweezers could be combined to study multiple molecules and cells simultaneously, providing a high-throughput capability for assessing the effects of mechanical forces on a broad scale.

For example, a cell that's binding the extracellular matrix may bind with one receptor while the matrix is being stretched, and a different receptor when it's not under stress. Those binding differences could drive changes in cell phenotype and affect processes such as cell differentiation. A device like this will allow us to interrogate what the specific binding sites are and what the specific binding triggers are.

Scientists have been able to study how single cells or proteins are affected by mechanical forces, but their activity can vary considerably from cell-to-cell and among molecules. The new tweezers, which are built using nanolithography, can facilitate studying thousands or more cells and proteins in aggregate.

At the center of the tweezers are few micron polystyrene microbeads that contain superparamagnetic nanoparticles. The tiny beads are engineered to adhere to a sample being studied. That sample is attached to a bead on one side, and to a magnetic pad on the other. The magnet draws the bead toward it, while an electrophoretic force created by current flowing through a gold wiring pattern pushes the bead away. The device simultaneously pushes and pulls on the same particle.

Because the forces can be varied, the tweezers can be used to study structures of widely different size scales, from protein molecules to cells. Absolute forces in the nano-Newton range applied by the two sources overcome the much smaller effects of Brownian motion and thermal energy, allowing the tweezers to hold the cells or molecules without constant adjustment.

As a proof of principle for the system, the researchers demonstrated its ability to distinguish between antigen binding to loaded magnetic beads coated with different antibodies. When a sufficient upward force is applied, non-specific antibody coated beads are displaced from the antigen-coated device surface, while beads coated with the specific antibody are more strongly attracted to the surface and retained on it.

Gold nanoparticles to observe the interaction of molecules in liquid

Thanks to a new device that is the size of a human hair, it is now possible to detect molecules in a liquid solution and observe their interactions. This is of major interest for the scientific community, as there is currently no reliable way of examining both the behavior and the chemical structure of molecules in a liquid in real time.

This process could potentially make a whole new class of measurements possible by bringing together infrared detection techniques and gold nanoparticles, which would be a critical step in understanding basic biological functions as well as key aspects of disease progression and treatment. This could also prove useful for studying the behaviour of proteins, medicines and cells in the blood or pollutants in water.

The device is based on infrared absorption spectroscopy. Infrared light can already be used to detect elements: The beam excites the molecules, which start to vibrate in different ways depending on their size, composition and other properties. It's like a guitar string vibrating differently depending on its length. The unique vibration of each type of molecule acts as a signature for that molecule.

This technique works very well in dry environments but not at all well in aqueous environments. A large number of molecules need to be present for them to be detected. It's also more difficult to detect molecules in water, as when the beam goes through the solution, the water molecules vibrate as well and interfere with the target molecule's. To get rid of this problem, the researchers have developed a system capable of isolating the target molecules and eliminating interferences.

The device is made up of miniature fluidic chambers with nano scale gold particles on one side of its cover. Now to catch a particular molecule gold nanoparticle is attached with specific antibodies. Once the target element is introduced in to the small chamber, nanoparticles get attached to the target element. This technique makes it possible to isolate the target molecules from the rest of the liquid. But this is not the only role the nanoparticles play. They are also capable of concentrating light in nanometer-size volumes around their surface as a result of plasmonic resonance.

In the chamber, the beam doesn't need to pass through the whole solution. Instead, it is sent straight to the nanoparticle, which concentrates the light. Caught in the trap, the target molecules are the only ones that are so intensely exposed to the photons. The reaction between the molecules and the infrared photons is extremely strong, which means they can be detected and observed very precisely. This technique enables to observe molecules in-situ as they react with elements in their natural environment. This could prove extremely useful for both medicine and biology.

Myths about toxic Nanosilver busted

According to Finnish-Estonian joint research with data obtained on two crustacean species, there is apparently no reason to consider silver nanoparticles more dangerous for aquatic ecosystems than silver ions. The results were reported in the journal Environmental Science and Pollution Research late last year.

Part of the magic of nano-science is that on the scale of a billionth of a metre, matter and materials behave in ways that are not yet known. It is also not very clear what types of effects the nano version of the parent matter will have on its environment.

Due to the fact that silver in nanoparticle form is bactericidal and also fungicidal and also prevents the reproduction of those organisms, it is now used in various consumer goods ranging from wound dressing products to sportswear, says Jukka Niskanen from the Laboratory of Polymer Chemistry at the University of Helsinki, Finland.

While the usefulness of silver has been established, the debate over the toxicity mechanisms of its various forms to microorganisms, but also to non-target species continues. Anne Kahru, Head of the Laboratory of Environmental Toxicology at the National Institute of Chemical Physics and Biophysics, Estonia, highlights on a new field: nanoecotoxicology.

So far, little is known about the environmental effects of silver nanoparticles and their toxicity to aquatic organisms. A joint study from the University of Helsinki and the National Institute of Chemical Physics and Biophysics, Estonia of two types of silver nanoparticles to aquatic crustaceans Daphnia magna and Thamnocephalus platyurus , shows that silver nanoparticles are apparently no more hazardous to aquatic ecosystems than a water-soluble silver salt. The study compared the ecotoxicity of silver nanoparticles and a water-soluble silver salt.

The conclusion was that the environmental risks caused by silver nanoparticles are seemingly not higher than those caused by a silver salt. However, more research is required to reach a clear understanding of the safety of silver-containing particles.

Indeed, silver nanoparticles were found to be ten times less toxic than the soluble silver nitrate -- a soluble silver salt used for the comparison.

To explain this phenomenon, the researchers refer to the variance in the bioavailability of silver to crustaceans in different tested media.

It has been observed that the inorganic and organic compounds dissolved in natural waters (such as humus), water hardness and sulfides have a definite impact on the bioavailability of silver. Due to this, the toxicity of both types of tested nanoparticles and the silver nitrate measured in the course of the study was lower in natural water than in artificial fresh water.

The toxicity of silver nanoparticles and silver ions was studied using two aquatic crustaceans, a water flea (Daphnia magna) and a fairy shrimp (Thamnocephalus platyurus). Commercially available protein-stabilised particles and particles coated with a water-soluble, non-toxic polymer, specifically synthesised for the purpose, were used in the study. First, the polymers were produced utilising a controlled radical polymerisation method. Synthetic polymer-grafted silver particles were then produced by attaching the water-soluble polymer to the surface of the silver with a sulfur bond.

It was previously known from other studies and research results that silver changes the functioning of proteins and enzymes. It has also been shown that silver ions can prevent the replication of DNA. Concerning silver nanoparticles, tests conducted on various species of bacteria and fungi have indicated that their toxicity varies. For example, gram-negative bacteria such as Escherichia coli are more sensitive to silver nanoparticles than gram-positive ones (such as Staphylococcus aureus). The difference in sensitivity is caused by the structural differences of the cell membranes of the bacteria. The cellular toxicity of silver nanoparticles in mammals has been studied as well. It has been suggested that silver nanoparticles enter cells via endocytosis and then function in the same manner as in bacterial cells, damaging DNA and hindering cell respiration. Electron microscope studies have shown that human skin is permeable to silver nanoparticles and that the permeability of damaged skin is up to four times higher than that of healthy skin.

Phosphor removal from nano iron

A professor at Michigan State University is part of a team developing a new method of removing phosphorus from wastewater; a problem seriously affecting lakes and streams across the world.

Phosphorus is part of all food as well as is in items such as detergents and fertilizer and remains a critical problem as it is always present in human and animal wastes.

Discharge from human and industrial wastewater and runoff into lakes and streams can cause eutrophication, making the water unsuitable for recreational purposes and reducing fish populations, as well as causing the growth of toxic algae.

Researchers have figured out and tested over the past 10 years is how to produce a media, enhanced with nanoparticles composed of iron, that can more efficiently remove larger amounts of phosphorus from water.

Phosphorus that is dissolved in wastewater, like sugar in water, is hard to remove. A nano-media made with waste iron can efficiently absorb it, making it a solid that can be easily and efficiently removed and recovered for beneficial reuse. Their method of phosphorus retrieval is much more cost effective than processing phosphate rock. Research suggests that it is significantly cheaper to recover phosphorus this way.

Ill effect of Carbon Nanoparticles

A study by researchers from the schools of science and medicine at Indiana University-Purdue University Indianapolis examines the effects of carbon nanoparticles (CNPs) on living cells. This work is among the first to study concentrations of these tiny particles that are low enough to mimic the actual exposure of an ordinary individual.

 The effects on the human body of exposure to CNPs -- minute chemicals with rapidly growing applications in electronics, medicine, and many other fields -- is just beginning to be revealed. Exposure at the level studied by the IUPUI researchers is approximately equivalent to what might be the result of improperly disposing of an item such as a television or computer monitor containing CNPs, living near a CNP producing facility, or working with CNPs.

The research focuses on the effect of low concentration CNP exposure on the cells that line the renal nephron, a tubular structure inside the kidney that makes urine. The investigators found the role of the CNPs in this part of the body to be significant and potentially worrisome.

Unlike many other studies,  low concentrations of CNPs have been used that are typically appear in the body after ingesting them from environmental contamination or even from breathing air with CNPs. These minute particles cause leakage in the cellular lining of the renal nephron.

Breaching this biological barrier cause great concerns because things that should be retained in the forming urine can leak back into the blood stream and things in the blood can leak into the urine. Normal biological substances as well as waste products are dangerous if they go where they are not supposed to be.

These CNPs don't kill cells; so they are not lethal, but they do affect cells, and in this case it's an adverse effect. Biological barriers are very important to human health. The two researchers note that these incredibly strong particles, visible only under an electron microscope, perform useful functions including roles in drug delivery and are responsible for many advances in electronics such as the impressive colors seen on plasma televisions and computer monitors. What they worry about is when CNPs enter the air and the environment and eventually the human body from inappropriate disposal or from manufacture of products containing the particles.

This study is part of the team's larger body of work, which looks at the effect of CNPs on barriers throughout the body including those of the airways and large intestine.

CNPs have many beneficial qualities, but also pose potential risks. These particles are so small that when they get into various organs or systems they can bind to many things. A further study is required for what they look like in various parts of the body, how they affect protein expression, as well as what they do when they cross a barrier or are excreted.

Nanobiotechnology Product Market Size

The total market for nanobiotechnology products is $19.3 billion in 2010 and is growing at a compound annual growth rate (CAGR) of 9% to reach a forecast market size of $29.7 billion by 2015.

Medical applications, including drug delivery and microbicides, dominate today’s market, with sales of $19.1 billion in 2010. This market segment is growing at a compound annual growth rate (CAGR) of 8.7%, and is forecast to reach sales of $29 billion by 2015.

In the R&D tools market, DNA sequencing is an emerging growth opportunity for nanotechnologies. This sector is valued at $63 million in 2010 and is expected to increase at a 37% compound annual growth rate (CAGR) to reach $305 million in 2015.

Advanced Nanogenerators for Versatile Applications

In the last article (http://nanosciencetech.blogspot.com/2010/11/self-powered-nanosensors-based-on-zinc.html) we have discussed about the nano generators basically based on the movement of the zinc oxide nanowires resulting the necessary piezoelectric effect to produce small amount of electricity. This technology can be very much utile in medical sciences, where there is a growing need for the surgery less equipments and supporting technology.

In a recent development, researchers have come up with a technique where they use the freely bendable piezoelectric ceramic thin film nano-materials that can convert tiny movements of the human body (such as heart beats and blood flow) into electrical energy. Thus these devices can be implanted in micro robot which can operate human organs without their battery charged.

The ceramics, containing a perovskite structure, have a high piezoelectric efficiency. Until now, it has been very difficult to use these ceramic materials to fabricate flexible electronic systems due to their brittle property. The research team, however, has succeeded in developing a bio-eco-friendly ceramic thin film nanogenerator that is freely bendable without breakdown.

Nanogenerator technology, a power generating system without wires or batteries, combines nanotechnology with piezoelectrics that can be used not only in personal mobile electronics but also in bio-implantable sensors or as an energy source for micro robots. Energy sources in nature (wind, vibration, and sound) and biomechanical forces produced by the human body (heart beats, blood flow, and muscle contraction/relaxation) can infinitely produce nonpolluting energy.

This technology can be used to turn on an LED by slightly modifying circuits and operate touchable flexible displays. In addition, thin film nano-materials have the property of both high efficiency and lead-free bio compatibility, which can be used in future medical applications.

Silicon Technology For Medical Application

A team of cardiologists, materials scientists, and bioengineers have created and tested a new type of implantable device for measuring the heart's electrical output that they say is a vast improvement over current devices. The new device represents the first use of flexible silicon technology for a medical application.

This technology may herald a new generation of active, flexible, implantable devices for applications in many areas of the body, commented Brian Litt, an associate professor of Neurology at the University Of Pennsylvania School Of Medicine and also an associate professor of Bioengineering in Penn's School of Engineering and Applied Science.

Implantable silicon-based devices have the potential to serve as tools for mapping and treating epileptic seizures, providing more precise control over deep brain stimulation, as well as other neurological applications, say Story Landis, PhD, director of the National Institute of Neurological Disorders and Stroke, which provided support for the study.

The new devices bring electronic circuits right to the tissue, rather than having them located remotely, inside a sealed can that is placed elsewhere in the body, such as under the collar bone or in the abdomen, explained Litt. This enables the devices to process signals right at the tissues, which allows them to have a much higher number of electrodes for sensing or stimulation than is currently possible in medical devices.

Now, for example, devices for mapping and eliminating life-threatening heart rhythms allow for up to 10 wires in a catheter that is moved in and around the heart, and is connected to rigid silicon circuits distant from the target tissue. This design limits the complexity and resolution of devices since the electronics cannot get wet or touch the target tissue.

The team tested the new devices - made of nanoscale, flexible ribbons of silicon embedded with 288 electrodes, forming a lattice-like array of hundreds of connections - on the heart of a porcine animal model. The tissue-hugging shape allows for measuring electrical activity with greater resolution in time and space. The new device can also operate when immersed in the body's salty fluids. The devices can collect large amounts of data from the body, at high speed. This allowed the researchers to map electrical activity on the heart of the large animal.

In this experiment, the researchers built a device to map waves of electrical activity in the heart of a large animal. The device uses the 288 contacts and more than 2,000 transistors spaced closely together, while standard clinical systems usually use about five to 10 contacts and no active transistors. High-density maps of electrical activity on the heart were recorded from the device, during both natural and paced beats.

Scientists are also planning to design advanced, intelligent pacemakers that can improve the pumping function of hearts weakened by heart attacks and other diseases. For each of these applications, the team is conducting experiments to test flexible devices in animals before starting human trials.

Another focus of ongoing work is to develop similar types of devices that are not only flexible, like a sheet of plastic, but fully stretchable, like a rubber band. The ability to fully conform and wrap around large areas of curved tissues will require stretch ability, as well as flexibility.

NANOCOMPOSITES COULD CHANGE DIABETES TREATMENT

The people who are suffering from diabetes may soon be able to wear contact lenses that continuously alert them to variations in their glucose levels by changing colors. This facility reduces the need to routinely draw blood throughout the day.

The non-invasive technology, developed by Chemical and Biochemical Engineering professor Jin Zhang at The University of Western Ontario, uses extremely small nanoparticles embedded into the hydrogel lenses. These engineered nanoparticles react with glucose molecules found in tears, causing a chemical reaction that changes their color.

Zhang received $216,342 from the Canada Foundation for Innovation (CFI)  to further develop technologies using multifunctional nanocomposites.These technologies have vast potential applications beyond biomedical devices, including for food packaging. For example, nanocomposite films can prevent food spoilage by preventing oxygen, carbon dioxide and moisture from reaching fresh meats and other foods, or by measuring pathogenic contamination; others can make packaging increasingly biodegradable.

NANOSCALE OPTICAL FIBERS FOR DETECTION OF BIOTERRORIST AGENTS

In an age when bacterial agents may be intentionally released as method of terrorist attack, there is an increased need for quick diagnostic methods that require limited resources and personnel. Thomas Inzana, the Tyler J. and Frances F. Young Chair of Bacteriology in the Virginia-Maryland Regional College of Veterinary Medicine at Virginia Tech, has been awarded a grant from the National Institutes of Health to develop such a diagnostic test.

He and his co-investigators, James “Randy” Heflin, a professor in the Department of Physics in the university’s College of Science, and Abey Bandera, a research assistant professor in the veterinary college, are working to develop nanoscale optical fiber biosensor tests, or assays, for detection of Francisella tularensis, Burkholderia mallei, and B. pseudomallei.

Currently, testing involves either the use of cultures in Biosecurity Level-3(BSL-3) laboratories, or since facilities do not have BSL-3 capabilities -- serology or antibody-based testing. Both require extensive materials and training, and the results can take days or weeks.

“This assay will be rugged, portable, inexpensive, and rapid,” said Inzana, who is also the associate vice president for research programs at the university. All of these are critical to minimizing the affect on an intentionally introduced biological weapon.

The increased speed of detection allowed by this new, optical fiber assay will also increase the speed of treatment for those affected, according to Inzana.

The optical fiber is coated with antibodies or DNA that will bind to antigens or DNA in the specimen. When this happens, the light that normally passes through the fiber will be decreased, indicating the presence of a biological agent.

According to Inzana, there are advantages and disadvantages to both. Antigens are more abundant and closer to the surface of the agent, but aren’t always very specific. DNA, however, is very specific, but is less plentiful and resides deep within the cell.

PARTICLE LENGTH CONTROLS THE TOXICITY AND BIOACTIVITY OF TITANIUM DIOXIDE NANOMATERIAL

Titanium dioxide (TiO2) nanomaterials have considerable beneficial applications varying from additives in paint, paper, plastics and cosmetics to uses in photocatalysts, solar cells and medical materials and devices. It has been established for many years that pigment-grade TiO2 (200 nm sphere) is relatively inert when internalized into a biological model system (in vivo or in vitro).

For this reason, TiO2 nanomaterials are an attractive alternative in applications where biological exposures will occur. Unfortunately, metal oxides on the nanoscale (one dimension <100 nm) may or may not exhibit the same toxic potential as the original material. A further complicating issue is the effect of modifying or engineering of the nanomaterial to be structurally and geometrically different from the original material. TiO2 nanospheres, short (<5 µm) and long (>15 µm) nanobelts were synthesized, characterized and tested for biological activity using primary murine alveolar macrophages and in vivo in mice. This study demonstrates that alteration of anatase TiO2 nanomaterial into a fibre structure of greater than 15 µm creates a highly toxic particle and initiates an inflammatory response by alveolar macrophages.

These fibre-shaped nanomaterials induced inflammasome activation and release of inflammatory cytokines through a cathepsin B-mediated mechanism. Consequently, long TiO2 nanobelts interact with lung macrophages in a manner very similar to asbestos or silica.

These observations suggest that any modification of a nanomaterial, resulting in a wire, fibre, belt or tube, be tested for pathogenic potential.

GOLD PARTICLES DELIVER MORE THAN JUST GLITTER!

Using tiny gold particles and infrared light, MIT researchers have developed a drug-delivery system that allows multiple drugs to be released in a controlled fashion. Such a system could one day be used to provide more control when battling diseases commonly treated with more than one drug, according to the researchers.

Delivery devices already exist that can release two drugs, but the timing of the release must be built into the device -- it cannot be controlled from outside the body. The new system is controlled externally and theoretically could deliver up to three or four drugs. The new technique takes advantage of the fact that when gold nanoparticles are exposed to infrared light, they melt and release drug payloads attached to their surfaces.

Nanoparticles of different shapes respond to different infrared wavelengths, so just by controlling the infrared wavelength, the release time can be chosen for each drug. The research team built two different shapes of nanoparticles, which they call "nanobones" and "nanocapsules." Nanobones melt at light wavelengths of 1,100 nanometers, and nanocapsules at 800 nanometers.

In the ACS Nano study, the researchers tested the particles with a payload of DNA. Each nanoparticle can carry hundreds of strands of DNA, and could also be engineered to transport other types of drugs. In theory, up to four different-shaped particles could be developed, each releasing its payload at different wavelengths.

DNA-WRAPPED CARBON NANOTUBES SERVE AS SENSORS IN LIVING CELLS

Single-walled carbon nanotubes wrapped with DNA can be placed inside living cells and detect trace amounts of harmful contaminants using near infrared light, report researchers at the University of Illinois at Urbana-Champaign. Their discovery opens the door to new types of optical sensors and biomarkers that exploit the unique properties of nanoparticles in living systems.This is the first nanotube-based sensor that can detect analytes at the subcellular level, said Michael Strano, a professor of chemical and biomolecular engineering at Illinois. They also showed for the first time that a subtle rearrangement of an adsorbed biomolecule can be directly detected by a carbon nanotube.

At the heart of the new detection system is the transition of DNA secondary structure from the native, right-handed "B" form to the alternate, left-handed "Z" form.It was observed that the thermodynamics that drive the switching back and forth between these two forms of DNA structure would modulate the electronic structure and optical emission of the carbon nanotube. To make their sensors, the researchers begin by wrapping a piece of double-stranded DNA around the surface of a single-walled carbon nanotube, in much the same fashion as a telephone cord wraps around a pencil. The DNA starts out wrapping around the nanotube with a certain shape that is defined by the negative charges along its backbone.When the DNA is exposed to ions of certain atoms - such as calcium, mercury and sodium - the negative charges become neutralized and the DNA changes shape in a similar manner to its natural shape-shift from the B form to Z form. This reduces the surface area covered by the DNA, perturbing the electronic structure and shifting the nanotube's natural, near infrared fluorescence to a lower energy.The change in emission energy indicates how many ions bind to the DNA. Removing the ions will return the emission energy to its initial value and flip the DNA back to the starting form, making the process reversible and reusable. The researchers demonstrated the viability of their measurement technique by detecting low concentrations of mercury ions in whole blood, opaque solutions, and living mammalian cells and tissues - examples where optical sensing is usually poor or ineffective. Because the signal is in the near infrared, a property unique to only a handful of materials, it is not obscured by the natural fluorescence of polymers and living tissues. The nanotube surface acts as the sensor by detecting the shape change of the DNA as it responds to the presence of target ions.

Exploring Nanotechnology: Infants get a new light

An Indian microbiologist is trying to use nanotechnology to help identify an opportunistic pathogen that colonises recto-vaginal areas in up to 50 per cent of women worldwide and causes several life-threatening diseases in infants. Atul Kumar Johri, Associate Professor at JNU's School of Life Sciences in New Delhi, is keen to develop a mechanism to identify Group B Streptococcus (GBS) bacteria that cause pneumonia, sepsis and meningitis in newborns and is responsible for significant morbidity in pregnant women and the elderly.

Dr. Johri along with scientists from the Queensland Institute of Medical Research in Australia is working on a project to make use of nanotechnology for rapid, more sensitive as well as efficient detection of the GBS bacteria in pregnant women.

In the U.S., the UK and France, there is a mandatory test for detection of GBS in pregnant women between 35-37 weeks of their pregnancy. If the bacteria are detected in their samples, four hours before the birth of the child penicillin shots are given to the women through intravenous injections so that they can prevent the bacteria from infecting the baby and causing pneumonia and meningitis.

In India, there is no such test or even much knowledge about the existence and prevention of GBS. The fact that a large number of childbirths in the country happen outside the health centres is another cause for worry.
“Timely detection of GBS can save a lot of babies in India. The problem is that in India, common people are not even aware of such a micro-organism, diseases that it causes, and that it is so easily preventable. GBS has nine serotypes. In India, Type I-A and Type III are predominant. After they made the test mandatory, the number of children getting infected with such diseases in the Western countries has come down significantly,” informs Dr. Johri. He is also working with the Australian researchers to develop one universal vaccine for the GBS.

VIRUS: Nano particle Memory Booster

A new type of digital memory device has been created by incorporating inorganic platinum nanoparticles into the tobacco mosaic virus (TMV).

The work was done by researchers at the University of California, Los Angeles (UCLA), who claim that the result could find application in the development of bio-compatible electronics.

In recent years researchers have exploited the unique selectivity of biomaterials by nanostructuring biological molecules with inorganic materials for applications such as biosensing. The UCLA researchers have taken this idea one-step further with a hybrid biological system that can store digital information.

“We have developed an electronic device, fabricated from the tobacco mosaic virus conjugated with nanoparticles, which exhibits a unique memory effect,” Yang Yang, the group’s lead researcher at the University of California, told physicsweb.org. “This device can be operated as an electrically bistable memory device whose conductance states can be controlled by a bias voltage. The states are non-volatile and can be digitally recognized.”

The TMV is a 300 nm tube consisting of a protein capsid (outer shell) and RNA core. According to the researchers, the TMV’s thin, wire-like structure makes it suitable for attaching nanoparticles. In this case, it allowed them to add an average of sixteen positive platinum ions per virion. The device works by transferring charge, under a high electric field, from the RNA to the Platinum nanoparticles with the TMV’s surface proteins acting as an energy barrier, stabilising the trapped charges.

“The TMV’s surface makes it an ideal template for organizing the nanoparticles, which can bind to the specific carboxyl or hydroxyl sites on the surface,” said Yang. “The RNA core in TMV is likely to serve as the charge donor to the nanoparticles with the coat proteins acting as the barrier to the charge transferring process.”

The TMV hybrid, says the team, has an access time ( the delay between a call for storing data and for data storing to begin) in the microsecond regime. This is comparable to today’s flash memory. In addition, the device is non-volatile, which means that data is retained once the computer’s power is turned off.

The researchers say the device still needs to be scaled-down to a smaller size to increase storage density and to include more circuitry. “There will be issues involving retention time, power consumption, and integration of drivers required to write and read each bit, which we need to consider in order to optimize the system,” said Yang.

In the long term, these devices could one day be integrated in biological tissues for applications in therapeutics or biocompatible electronics.