Friday, October 31, 2014

Breakthrough in molecular electronics paves way for new generation of DNA-based computer circuits



Paving the way for a new generation of DNA-based computer circuits: Prof. Danny Porath, the Etta and Paul Schankerman Professor in Molecular Biomedicine at the Hebrew University of Jerusalem.

In a paper published today in Nature Nanotechnology, an international group of scientists announced the most significant breakthrough in a decade toward developing DNA-based electrical circuits.

The central technological revolution of the 20th century was the development of computers, leading to the communication and Internet era. The main measure of this evolution is miniaturization: making our machines smaller. A computer with the memory of the average laptop today was the size of a tennis court in the 1970s.
Yet while scientists made great strides in reducing of the size of individual computer components through microelectronics, they have been less successful at reducing the distance between transistors, the main element of our computers. These spaces between transistors have been much more challenging and extremely expensive to miniaturize -- an obstacle that limits the future development of computers.
Molecular electronics, which uses molecules as building blocks for the fabrication of electronic components, was seen as the ultimate solution to the miniaturization challenge. However, to date, no one has actually been able to make complex electrical circuits using molecules. The only known molecules that can be pre-designed to self-assemble into complex miniature circuits, which could in turn be used in computers, are DNA molecules. Nevertheless, so far no one has been able to demonstrate reliably and quantitatively the flow of electrical current through long DNA molecules.
Now, an international group led by Prof. Danny Porath of the Hebrew University of Jerusalem reports reproducible and quantitative measurements of electricity flow through long molecules made of four DNA strands, signaling a significant breakthrough towards the development of DNA-based electrical circuits. The research, which could re-ignite interest in the use of DNA-based wires and devices in the development of programmable circuits, appears in the journal Nature Nanotechnologyunder the title "Long-range charge transport in single G-quadruplex DNA molecules."
Prof. Porath is affiliated with the Hebrew University's Institute of Chemistry and its Center for Nanoscience and Nanotechnology. The molecules were produced by the group of Alexander Kotlyar from Tel Aviv University, who has been collaborating with Porath for 15 years. The measurements were performed mainly by Gideon Livshits, a PhD student in the Porath group, who carried the project forward with great creativity, initiative and determination. The research was carried out in collaboration with groups from Denmark, Spain, US, Italy and Cyprus.

Thursday, October 30, 2014

New nanodevice to improve cancer treatment monitoring


In less than a minute, a miniature device can measure a patient's blood for methotrexate, a commonly used but potentially toxic cancer drug. Just as accurate and ten times less expensive than equipment currently used in hospitals, this nanoscale device has an optical system that can rapidly gauge the optimal dose of methotrexate a patient needs, while minimizing the drug's adverse effects.

The gold nanonparticules on the surface of this receiving tab modify the colour of light detected by the instrument. The captured colour perfectly reflects the exact concentration of the medication in the blood sample. Les nanoparticules d'or situées à la surface de la languette réceptrice modifient la couleur de la lumière détectée par l'instrument. La couleur captée reflète la concentration exacte du médicament contenu dans l'échantillon sanguin.

New material advances tissue engineering, drug delivery

Researchers at the New York University Polytechnic School of Engineering have broken new ground in the development of proteins that form specialized fibers used in medicine and nanotechnology. For as long as scientists have been able to create new proteins that are capable of self-assembling into fibers, their work has taken place on the nanoscale. For the first time, this achievement has been realized on the microscale—a leap of magnitude in size that presents significant new opportunities for using engineered protein fibers.

Jin Kim Montclare, an associate professor of chemical and biomolecular engineering at the NYU School of Engineering, led a group of researchers who published the results of successful trials in the creation of engineered microfiber proteins in the journal Biomacromolecules.

Many materials used in medicine and nanotechnology rely on proteins engineered to form fibers with specific properties. For example, the scaffolds used in tissue engineering depend on engineered fibers, as do the nanowires used in biosensors. These fibers can also be bound with small molecules of therapeutic compounds and used in drug delivery.

Tuesday, October 28, 2014

Tiny nano-sized particles may play major role in detecting, tracking breast cancer

Exosomes, tiny, virus-sized particles released by cancer cells, can bioengineer micro-RNA (miRNA) molecules resulting in tumor growth. They do so with the help of proteins, such as one named Dicer. New research from The University of Texas MD Anderson Cancer Center suggests Dicer may also serve as a biomarker for breast cancer and possibly open up new avenues for diagnosis and treatment. Results from the investigation were published in today's issue of Cancer Cell.

"Exosomes derived from cells and blood serum of patients with breast cancer, have been shown to initiate tumor growth in non-tumor-forming cells when Dicer and other proteins associated with the development of miRNAs are present," said Raghu Kalluri, M.D., Ph.D., chair of the department of cancer biology at MD Anderson. "These findings offer opportunities for the development of exosomes-based biomarkers and shed insight into the mechanisms of how cancer spreads."

Ref : http://www.mdanderson.org/newsroom/news-releases/2014/breast-cancer-exosomes-cancer-progression.html

Wednesday, October 22, 2014

Tuning light to kill deep cancer tumors


An international group of scientists has combined a new type of nanoparticle with an FDA-approved photodynamic therapy to effectively kill deep-set cancer cells in vivo with minimal damage to surrounding tissue and fewer side effects than chemotherapy. This promising new treatment strategy could expand the current use of photodynamic therapies to access deep-set cancer tumors.
"We are very excited at the potential for clinical practice using our enhanced red-emission nanoparticles combined with FDA-approved photodynamic drug therapy to kill malignant cells in deeper tumors," said Dr. Han, lead author of the study and assistant professor of biochemistry and molecular pharmacology at UMMS. "We have been able to do this with biocompatible low-power, deep-tissue-penetrating 980-nm near-infrared light."
In photodynamic therapy, also known as PDT, the patient is given a non-toxic light-sensitive drug, which is absorbed by all the body's cells, including the cancerous ones. Red laser lights specifically tuned to the drug molecules are then selectively turned on the tumor area. When the red light interacts with the photosensitive drug, it produces a highly reactive form of oxygen (singlet oxygen) that kills the malignant cancer cells while leaving most neighboring cells unharmed.
Because of the limited ability of the red light to penetrate tissue, however, current photodynamic therapies are only used for skin cancer or lesions in very shallow tissue. The ability to reach deeper set cancer cells could extend the use of photodynamic therapies.
In research published online by the journal ACS Nano of the American Chemical Society, Han and colleagues describe a novel strategy that makes use of a new class of upconverting nanoparticles (UCNPs), a billionth of a meter in size, which can act as a kind of relay station. These UCNPs are administered along with the photodynamic drug and convert deep penetrating near-infrared light into the visible red light that is needed in photodynamic therapies to activate the cancer-killing drug.
To achieve this light conversion, Han and colleagues engineered a UCNP to have better emissions in the red part of the spectrum by coating the nanoparticles with calcium fluoride and increasing the doping of the nanoparticles with ytterbium.
In their experiments, the researchers used the low-cost, FDA-approved photosensitizer drug aminolevulinic acid and combined it with the augmented red-emission UCNPs they had developed. Near-infrared light was then turned on the tumor location. Han and colleagues showed that the UCNPs successfully converted the near-infrared light into red light and activated the photodynamic drug at levels deeper than can be currently achieved with photodynamic therapy methods. Performed in both in vitro and with animal models, the combination therapy showed an improved destruction of the cancerous tumor using lower laser power.
Yong Zhang, PhD, chair professor of National University of Singapore and a leader in the development and application of upconversion nanoparticles, who was not involved in the study, said that by successfully engineering amplified red emissions in these nanoparticles, the research team has created the deepest-ever photodynamic therapy using an FDA-approved drug.
"This therapy has great promise as a noninvasive killer for malignant tumors that are beyond 1 cm in depth -- breast cancer, lung cancer, and colon cancer, for example -- without the side-effects of chemotherapy," Zhang said.
Han said, "This approach is an exciting new development for cancer treatment that is both effective and nontoxic, and it also opens up new opportunities for using the augmented red-emission nanoparticles in other photonic and biophotonic applications.
Ref : http://www.umassmed.edu/news/research/


Tuesday, October 21, 2014

Facetless crystals that mimic starfish shells could advance 3-D-printing pills

Facetless crystals that mimic starfish shells could advance 3-D-printing pills 

Ultra-fast charging batteries that can be 70% recharged in just two minutes


Scientists have developed a new battery that can be recharged up to 70 per cent in only 2 minutes. The battery will also have a longer lifespan of over 20 years. Expected to be the next big thing in battery technology, this breakthrough has a wide-ranging impact on many industries, especially for electric vehicles which are currently inhibited by long recharge times of over 4 hours and the limited lifespan of batteries.
Scientists from Nanyang Technological University (NTU Singapore) have developed a new battery that can be recharged up to 70 per cent in only 2 minutes. The battery will also have a longer lifespan of over 20 years.
Expected to be the next big thing in battery technology, this breakthrough has a wide-ranging impact on many industries, especially for electric vehicles which are currently inhibited by long recharge times of over 4 hours and the limited lifespan of batteries.
This next generation of lithium-ion batteries will enable electric vehicles to charge 20 times faster than the current technology. With it, electric vehicles will also be able to do away with frequent battery replacements. The new battery will be able to endure more than 10,000 charging cycles -- 20 times more than the current 500 cycles of today's batteries.
NTU Singapore's scientists replaced the traditional graphite used for the anode (negative pole) in lithium-ion batteries with a new gel material made from titanium dioxide, an abundant, cheap and safe material found in soil. It is commonly used as a food additive or in sunscreen lotions to absorb harmful ultraviolet rays.
Naturally found in a spherical shape, NTU Singapore developed a simple method to turn titanium dioxide particles into tiny nanotubes that are a thousand times thinner than the diameter of a human hair.
This nanostructure is what helps to speeds up the chemical reactions taking place in the new battery, allowing for superfast charging.
Invented by Associate Professor Chen Xiaodong from the School of Materials Science and Engineering at NTU Singapore, the science behind the formation of the new titanium dioxide gel was published in the latest issue of Advanced Materials, a leading international scientific journal in materials science.
NTU professor Rachid Yazami, who was the co-inventor of the lithium-graphite anode 34 years ago that is used in most lithium-ion batteries today, said Prof Chen's invention is the next big leap in battery technology.
"While the cost of lithium-ion batteries has been significantly reduced and its performance improved since Sony commercialised it in 1991, the market is fast expanding towards new applications in electric mobility and energy storage," said Prof Yazami.
"There is still room for improvement and one such key area is the power density -- how much power can be stored in a certain amount of space -- which directly relates to the fast charge ability. Ideally, the charge time for batteries in electric vehicles should be less than 15 minutes, which Prof Chen's nanostructured anode has proven to do."
Prof Yazami, who is Prof Chen's colleague at NTU Singapore, is not part of this research project and is currently developing new types of batteries for electric vehicle applications at the Energy Research Institute at NTU (ERI@N).
Commercialisation of technology
Moving forward, Prof Chen's research team will be applying for a Proof-of-Concept grant to build a large-scale battery prototype. The patented technology has already attracted interest from the industry.........

Monday, October 20, 2014

Bio-inspired 'nano-cocoons' offer targeted drug delivery against cancer cells -- ScienceDaily

Biomedical engineering researchers have developed a drug delivery system consisting of nanoscale “cocoons” made of DNA that target cancer cells and trick the cells into absorbing the cocoon before unleashing anticancer drugs. 

omedical engineering researchers have developed a drug delivery system consisting of nanoscale “cocoons” made of DNA that target cancer cells and trick the cells into absorbing the cocoon before unleashing anticancer drugs. The work was done by researchers at North Carolina State University and the University of North Carolina at Chapel Hill.
“This drug delivery system is DNA-based, which means it is biocompatible and less toxic to patients than systems that use synthetic materials,” says Dr. Zhen Gu, senior author of a paper on the work and an assistant professor in the joint biomedical engineering program at NC State and UNC Chapel Hill.
“This technique also specifically targets cancer cells, can carry a large drug load and releases the drugs very quickly once inside the cancer cell,” Gu says.
“In addition, because we used self-assembling DNA techniques, it is relatively easy to manufacture,” says Wujin Sun, lead author of the paper and a Ph.D. student in Gu’s lab.
Each nano-cocoon is made of a single strand of DNA that self-assembles into what looks like a cocoon, or ball of yarn, that measures 150 nanometers across.
The core of the nano-cocoon contains the anticancer drug doxorubicin (DOX) and a protein called DNase. The DNase, an enzyme that would normally cut up the DNA cocoon, is coated in a thin polymer that traps the DNase like a sword in a sheath.
The surface of the nano-cocoon is studded with folic acid ligands. When the nano-cocoon encounters a cancer cell, the ligands bind the nano-cocoon to receptors on the surface of the cell – causing the cell to suck in the nano-cocoon.
Once inside the cancer cell, the cell’s acidic environment destroys the polymer sheath containing the DNase. Freed from its sheath, the DNase rapidly slices through the DNA cocoon, spilling DOX into the cancer cell and killing it.
“We’re preparing to launch preclinical testing now,” Gu says. “We’re very excited about this system and think it holds promise for delivering a variety of drugs targeting cancer and other diseases.”


Wednesday, October 15, 2014

Nanoparticles can act like liquid on the outside, crystal on the inside


A surprising phenomenon has been found in metal nanoparticles: They appear, from the outside, to be liquid droplets, wobbling and readily changing shape, while their interiors retain a perfectly stable crystal configuration.
The research team behind the finding, led by MIT professor Ju Li, says the work could have important implications for the design of components in nanotechnology, such as metal contacts for molecular electronic circuits.
The results, published in the journal Nature Materials, come from a combination of laboratory analysis and computer modeling, by an international team that included researchers in China, Japan, and Pittsburgh, as well as at MIT.
The experiments were conducted at room temperature, with particles of pure silver less than 10 nanometers across -- less than one-thousandth of the width of a human hair. But the results should apply to many different metals, says Li, senior author of the paper and the BEA Professor of Nuclear Science and Engineering.
Silver has a relatively high melting point -- 962 degrees Celsius, or 1763 degrees Fahrenheit -- so observation of any liquidlike behavior in its nanoparticles was "quite unexpected," Li says. Hints of the new phenomenon had been seen in earlier work with tin, which has a much lower melting point, he says.......
Ref : http://dx.doi.org/10.1038/nmat4105

Friday, October 10, 2014

Drug-infused nanoparticle is right for sore eyes

For the millions of sufferers of dry eye syndrome, their only recourse to easing the painful condition is to use drug-laced eye drops three times a day. Now, researchers from the University of Waterloo have developed a topical solution containing nanoparticles that will combat dry eye syndrome with only one application a week.
The eye drops progressively deliver the right amount of drug-infused nanoparticles to the surface of the eyeball over a period of five days before the body absorbs them. One weekly dose replaces 15 or more to treat the pain and irritation of dry eyes.
The nanoparticles, about 1/1000th the width of a human hair, stick harmlessly to the eye's surface and use only five per cent of the drug normally required.
"You can't tell the difference between these nanoparticle eye drops and water," said Shengyan (Sandy) Liu, a PhD candidate at Waterloo's Faculty of Engineering, who led the team of researchers from the Department of Chemical Engineering and the Centre for Contact Lens Research. "There's no irritation to the eye."
Dry eye syndrome is a more common ailment for people over the age of 50 and may eventually lead to eye damage. More than six per cent of people in the U.S. have it. Currently, patients must frequently apply the medicine three times a day because of the eye's ability to self-cleanse -- a process that washes away 95 per cent of the drug.
"I knew that if we focused on infusing biocompatible nanoparticles with Cyclosporine A, the drug in the eye drops, and make them stick to the eyeball without irritation for longer periods of time, it would also save patients time and reduce the possibility of toxic exposure due to excessive use of eye drops," said Liu.
The research team is now focusing on preparing the nanoparticle eye drops for clinical trials with the hope that this nanoparticle therapy could reach the shelves of drugstores within five years.
Liu's research article, co-authored by eight others including Professors Frank Gu and Lyndon Jones from Waterloo, recently appeared in Nano Research, the leading publication on nanotechnology and nanoscience. The Natural Sciences and Engineering Research Council of Canada (NSERC) and 20/20: Ophthalmic Materials Network supported the research.

Ref : http://link.springer.com/article/10.1007%2Fs12274-014-0547-3

Tuesday, October 7, 2014

Nanoparticles break the symmetry of light



How can a beam of light tell the difference between left and right? Tiny particles have now been coupled to a glass fiber. The particles emit light into the fiber in such a way that it does not travel in both directions, as one would expect. Instead, the light can be directed either to the left or to the right. This has become possible by employing a remarkable physical effect – the spin-orbit coupling of light. This new kind of optical switch has the potential to revolutionize nanophotonics.

Monday, October 6, 2014

Fast, cheap nanomanufacturing: Tiny conical tips fabricate nanoscale devices cheaply

Fast, cheap nanomanufacturing: Tiny conical tips fabricate nanoscale devices cheaply


Scientists have developed dense arrays of microscopic cones that harness electrostatic forces to eject streams of ions. The technology has a range of promising applications: depositing or etching features onto nanoscale mechanical devices; spinning out nanofibers for use in water filters, body armor, and "smart" textiles; or propulsion systems for fist-sized "nanosatellites." 

Sunday, October 5, 2014

Nanotechnology: Fullerene spheres can be used to slide in the nanoworld



“Nano–machines” (around one billionth of a meter in size) of the future will need tiny devices to reduce friction and make movement possible. The C60 molecule, also known as fullerene or buckyball, seemed to many an excellent candidate for nano-bearings. Unfortunately, the results so far have been conflicting, calling for further studies, like the one just carried out by a theoretical team. Through a series of computer simulations the scientists uncovered the reason for the experimental discrepancies and shed light on the true potential of this material.


Wednesday, October 1, 2014

Graphene looks promising as a flexible, low-cost touchscreen solution

The majority of today's touchscreen devices, such as tablets and smartphones are made using indium tin oxide (ITO) which is both expensive and inflexible. Researchers from the University of Surrey and AMBER, the materials science centre based at Trinity College Dublin have now demonstrated how graphene-treated nanowires can be used to produce flexible touchscreens at a fraction of the current cost.
Using a simple, scalable and inexpensive method the researchers produced hybrid electrodes, the building blocks of touchscreen technology, from silver nanowires and graphene.
Dr Alan Dalton from the University of Surrey said, "The growing market in devices such as wearable technology and bendable smart displays poses a challenge to manufacturers. They want to offer consumers flexible, touchscreen technology but at an affordable and realistic price. At the moment, this market is severely limited in the materials to hand, which are both very expensive to make and designed for rigid, flat devices."
Lead author, Dr Izabela Jurewicz from the University of Surrey commented, "Our work has cut the amount of expensive nanowires required to build such touchscreens by more than fifty times as well as simplifying the production process. We achieved this using graphene, a material that can conduct electricity and interpret touch commands whilst still being transparent."
Co-author, Professor Jonathan Coleman, AMBER, added, "This is a real alternative to ITO displays and could replace existing touchscreen technologies in electronic devices. Even though this material is cheaper and easier to produce, it does not compromise on performance."
Ref : http://onlinelibrary.wiley.com/doi/10.1002/adfm.201402547/abstract;jsessionid=A8B5D768DFFCF26CD77B3771E1931A35.f02t02