Articles from April 2014

DNA Nanoparticles To Kill Brain Cancer Cells

Working together, Johns Hopkins biomedical engineers and neurosurgeons report that they have created tiny, biodegradablenanoparticles” able to carry DNA to brain cancer cells in mice. The team says the results of their proof of principle experiment suggest that such particles loaded with “death genes” might one day be given to brain cancer patients during neurosurgery to selectively kill off any remaining tumor cells without damaging normal brain tissue.

Biodegradable plastic molecules (orange) self-assemble with DNA molecules (intertwined, black circles) to form tiny nanoparticles that can carry genes to cancer cells
“In our experiments, our nanoparticles successfully delivered a test gene to brain cancer cells in mice, where it was then turned on,” says Jordan Green, Ph.D., an assistant professor of biomedical engineering and neurosurgery at the Johns Hopkins University School of Medicine. “We now have evidence that these tiny Trojan horses will also be able to carry genes that selectively induce death in cancer cells, while leaving healthy cells healthy.”

A summary of the research results appeared online in the journal ACS Nano.

New High Capacity Flexible Battery

A Rice University laboratory has flexible, portable and wearable electronics in its sights with the creation of a thin film for energy storage. Rice chemist James Tour and his colleagues have developed a flexible material with nanoporous nickel-fluoride electrodes layered around a solid electrolyte to deliver battery-like supercapacitor performance that combines the best qualities of a high-energy battery and a high-powered supercapacitor without the lithium found in commercial batteries today.
Their electrochemical capacitor is about a hundredth of an inch thick but can be scaled up for devices either by increasing the size or adding layers, said Rice postdoctoral researcher Yang Yang, co-lead author of the paper with graduate student Gedeng Ruan. They expect that standard manufacturing techniques may allow the battery to be even thinner. In tests, the students found their square-inch device held 76 percent of its capacity over 10,000 charge-discharge cycles and 1,000 bending cycles. Tour said the team set out to find a material that has the flexible qualities of graphene, carbon nanotubes and conducting polymers while possessing much higher electrical storage capacity typically found in inorganic metal compounds. Inorganic compounds have, until recently, lacked flexibility, he said.

This is not easy to do, because materials with such high capacity are usually brittle,” he said. “And we’ve had really good, flexible carbon storage systems in the past, but carbon as a material has never hit the theoretical value that can be found in inorganic systems, and nickel fluoride in particular.”

Compared with a lithium-ion device, the structure is quite simple and safe,” Yang said. “It behaves like a battery but the structure is that of a supercapacitor. If we use it as a supercapacitor, we can charge quickly at a high current rate and discharge it in a very short time. But for other applications, we find we can set it up to charge more slowly and to discharge slowly like a battery.
The new work by the Rice lab of chemist James Tour is detailed in the Journal of the American Chemical Society.


Tiny Magnetic DNA Used As Invisible Label

The worldwide need for anti-counterfeiting labels for food is substantial. In a joint operation in December 2013 and January 2014, Interpol and Europol confiscated more than 1,200 tonnes of counterfeit or substandard food and almost 430,000 litres of counterfeit beverages. The illegal trade is run by organised criminal groups that generate millions in profits, say the authorities. The confiscated goods also included more than 131,000 litres of oil and vinegar. A forgery-proof label should not only be invisible but also safe, robust, cheap and easy to detect. To fulfil these criteria ETH researchers – Switzerland – used nanotechnology and nature’s information storehouse, DNA. A piece of artificial genetic material is the heart of the mini-label.
Just a few grams of the new substance are enough to tag the entire olive oil production of Italy. If counterfeiting were suspected, the particles added at the place of origin could be extracted from the oil and analysed, enabling a definitive identification of the producer.

Using magnetic DNA particles, olive oil can be tagged to prevent counterfeiting
The method is equivalent to a label that cannot be removed,” says Robert Grass, lecturer in the Department of Chemistry and Applied Biosciences at ETH Zurich.
However, DNA also has some disadvantages. If the material is used as an information carrier outside a living organism, it cannot repair itself and is susceptible to light, temperature fluctuations and chemicals. Thus, the researchers used a silica coating to protect the DNA, creating a kind of synthetic fossil. The casing represents a physical barrier that protects the DNA against chemical attacks and completely isolates it from the external environment – a situation that mimics that of natural fossils, write the researchers in their paper, which has been published in the journal ACS Nano.

Smartphones Printed On T-shirts

A new version of “spaser” technology being investigated could mean that mobile phones become so small, efficient, and flexible they could be printed on clothing.
A team of researchers from Monash University – Australia – Department of Electrical and Computer Systems Engineering (ECSE) has modelled the world’s first spaser (surface plasmon amplification by stimulated emission of radiation) to be made completely of carbon.
A spaser is effectively a nanoscale laser or nanolaser. It emits a beam of light through the vibration of free electrons, rather than the space-consuming electromagnetic wave emission process of a traditional laser.
PhD student and lead researcher Chanaka Rupasinghe said the modelled spaser design using carbon would offer many advantages.

Other spasers designed to date are made of gold or silver nanoparticles and semiconductor quantum dots while our device would be comprised of a graphene resonator and a carbon nanotube gain element,” Chanaka said.
The use of carbon means our spaser would be more robust and flexible, would operate at high temperatures, and be eco-friendly.
Because of these properties, there is the possibility that in the future an extremely thin mobile phone could be printed on clothing.”


How To Heat Your House At Night With Sun’s Energy

It’s an obvious truism, but one that may soon be outdated: The problem with solar power is that sometimes the sun doesn’t shine. Now a team at the Massachusetts Institute of Technology ( MIT) and Harvard University has come up with an ingenious workaround — a material that can absorb the sun’s heat and store that energy in chemical form, ready to be released again on demand. This solution is no solar-energy panacea: While it could produce electricity, it would be inefficient at doing so. But for applications where heat is the desired output — whether for heating buildings, cooking, or powering heat-based industrial processes — this could provide an opportunity for the expansion of solar power into new realms.

It could change the game, since it makes the sun’s energy, in the form of heat, storable and distributable,” says Jeffrey Grossman, the Carl Richard Soderberg Associate Professor of Power Engineering at MIT, who is a co-author of a paper describing the new process in the journal Nature Chemistry. Timothy Kucharski, a postdoc at MIT and Harvard, is the paper’s lead author.

Very Cheap, Powerful Solar Cells

Working on dye-sensitized solar cells – researchers from University Malaya (UM) – Indonesia – and National Tsing Hua University (NTHU) – Taiwan – have achieved an efficiency of 1.12 %, at a fraction of the cost compared to those used by platinum devices.
The study carried out in Taiwan took on the challenge of making the technology behind dye-sensitized solar cells more affordable by replacing the costly platinum counter-electrodes with bismuth telluride (Bi2Te3) nanosheet arrays.
Using a novel electrolysis process, the group managed to closely manipulate the spacing between individual nanosheets and hence control the thermal and electrical conductivity parameters to achieve the high efficiency of 1.12%, which is comparable to platinum devices, but at only at a fraction of the cost.
The research was led by Prof. Yu-Lun Chueh of the Nanoscience & Nanodevices Laboratory, NTHU, and Alireza Yaghoubi, UM HIR Young Scientist.

In light of the recent report by the United Nations about the irreversible effects of fossil fuels on climate change and as we gradually run out of economically recoverable oil reserves, we think it is necessary to look for a sustainable, yet practical source of energy” Yaghoubi stated.
Meanwhile at University Malaya, Dr. Wee Siong Chiu and colleagues were working on controlling the secondary nucleation and self-assembly in zinc oxide (ZnO), a material which is currently being scrutinized for its potential applications in dye-sensitized solar cells as well as photocatalytic reactions to generate clean electricity by splitting water under sunlight.
This work has been accepted for publication in the journal, Nanoscale published by the Royal Society of Chemistry and has been selected for the front cover of the issue.

Measuring DNA Repairs To Predict Cancer

Test analyzing cells’ ability to fix different kinds of broken DNA could help doctors predict cancer risk. Now a research team, led by professor Leona Samson from the Massachusetts Institute of Technology (MIT) used this approach to measure DNA repair in a type of immortalized human blood cells called lymphoblastoid cells, taken from 24 healthy people. They found a huge range of variability, especially in one repair system where some people’s cells were more than 10 times more efficient than others.
Our DNA is under constant attack from many sources, including environmental pollutants, ultraviolet light, and radiation. Fortunately, cells have several major DNA repair systems that can fix this damage, which may lead to cancer and other diseases if not mended.
The effectiveness of these repair systems varies greatly from person to person; scientists believe that this variability may explain why some people get cancer while others exposed to similar DNA-damaging agents do not. The team of MIT researchers has now developed a test that can rapidly assess several of these repair systems, which could help determine individuals’ risk of developing cancer and help doctors predict how a given patient will respond to chemotherapy drugs.

All of the repair pathways work differently, and the existing technology to measure each of those pathways is very different for each one. It takes expertise, it’s time-consuming, and it’s labor-intensive,” says Zachary Nagel, an MIT postdoc and lead author of the PNAS paper. “What we wanted to do was come up with one way of measuring all DNA repair pathways at the same time so you have a single readout that’s easy to measure.

None of the cells came out looking the same. They each have their own spectrum of what they can repair well and what they don’t repair well. It’s like a fingerprint for each person,” says Samson, who is the Uncas and Helen Whitaker Professor, an American Cancer Society Professor, and a member of MIT’s departments of biological engineering and of biology, Center for Environmental Health Sciences, and Koch Institute for Integrative Cancer Research.

The new test, described in the Proceedings of the National Academy of Sciences the week of April 21, can analyze four types of DNA repair capacity simultaneously, in less than 24 hours.

How To Close Deep Wounds In A Few Seconds

A significant breakthrough could revolutionize surgical practice and regenerative medicine. A team led by Ludwik Leibler from the Laboratoire Matière Molle et Chimie (CNRS/ESPCI Paris Tech) and Didier Letourneur from the Laboratoire Recherche Vasculaire Translationnelle (INSERM/Université Paris Diderot and Université Paris 13) – France -, has just demonstrated that the principle of adhesion by aqueous solutions of nanoparticles can be used in vivo to repair soft-tissue organs and tissues.

This easy-to-use gluing method has been tested on rats. When applied to skin, it closes deep wounds in a few seconds and provides aesthetic, high quality healing. It has also been shown to successfully repair organs that are difficult to suture, such as the liver. Finally, this solution has made it possible to attach a medical device to a beating heart, demonstrating the method’s potential for delivering drugs and strengthening tissues.
This work has been published on the website of the journal Angewandte Chemie.

Nanorobots Injected Inside Cockroaches

A team of scientists from the the Institute of Nanotechnology and Advanced Materials at Israel’s Bar-Ilan University has constructed minute robots that can function inside a living animal entity. The nanobots act upon chemical stimuli inside the body; that is, upon receiving a chemical signal, they react, displaying appropriate responses. The robots were made by using DNA. The DNA was packed together into strands, and this is what make up the robots. Upon stimulated by chemicals, the robots would then unravel into the two strands of DNA. The DNA binds and unbinds in different circumstances, and this is the basis of the way the robots operate to be stimulated and to react.

They work at the cellular level, and that is where their extremely small size helps enormously. They might be tiny, but their tininess is what confers on them their herculean potential to tackle tumors and repairing broken tissues. Moreover, the nanobots can act as real computers inside the body. Therefore, they can be programmed to do a certain list of jobs which their makers choose for them.
The cobaye used to test the nanorobots were cockroaches. They – those terribly annoying creatures – could at least be rendered useful, right?! The cockroach species Blaberus discoidalis was used for the insertion of the nanorobots. The robots were crammed with chemicals, which, upon recognising hemolymph cells found in the cockroach, would bind to them. Hemolymph cells are, in fact, the equivalent of white blood cells in the cockroach. Different kinds of robots were made to enter the body of the unsuspecting cockroach.
The next step now would be to use other animals as cobayes before actually marketing these nanorobots in medical institutions for humans.

Super Powerful Batteries To Extend Electric Car Range

Electric vehicles could travel farther and more renewable energy could be stored with lithium-sulfur batteries that use a unique powdery nanomaterial.
Researchers from The Department of Energy’s Pacific Northwest National Laboratory added the powder, a kind of nanomaterial called a metal organic framework, to the battery’s cathode to capture problematic polysulfides that usually cause lithium-sulfur batteries to fail after a few charges.

Lithium-sulfur batteries have the potential to power tomorrow’s electric vehicles, but they need to last longer after each charge and be able to be repeatedly recharged,” said materials chemist Jie Xiao of the Department of Energy’s Pacific Northwest National Laboratory. “Our metal organic framework may offer a new way to make that happen.
Today’s electric vehicles are typically powered by lithium-ion batteries. But the chemistry of lithium-ion batteries limits how much energy they can store. As a result, electric vehicle drivers are often anxious about how far they can go before needing to charge. One promising solution is the lithium-sulfur battery, which can hold as much as four times more energy per mass than lithium-ion batteries. This would enable electric vehicles to drive farther on a single charge, as well as help store more renewable energy. The down side of lithium-sulfur batteries, however, is they have a much shorter lifespan because they can’t currently be charged as many times as lithium-ion batteries.

A paper describing the material and its performance was published online April 4 in the American Chemical Society journal Nano Letters.

How To Deliver 3 Cancer Drugs At A Time.

Chemists from the Massachusetts Institute of Technology (MIT) have devised a way to build new nanoparticles, making it much easier to include three or more different drugs. The researchers, under the supervision of Jeremiah Johnson, an assistant professor of chemistry at MIT showed that they could load their particles with three drugs commonly used to treat ovarian cancer.
Such particles could be designed to carry even more drugs, allowing researchers to develop new treatment regimens that could better kill cancer cells while avoiding the side effects of traditional chemotherapy. Johnson set out to create a new type of particle that would enable the loading of any number of different drugs.

We think it’s the first example of a nanoparticle that carries a precise ratio of three drugs and can release those drugs in response to three distinct triggering mechanisms,”.
This is a new way to build the particles from the beginning,” Johnson says.
If I want a particle with five drugs, I just take the five building blocks I want and have those assemble into a particle. In principle, there’s no limitation on how many drugs you can add, and the ratio of drugs carried by the particles just depends on how they are mixed together in the beginning.
Longyan Liao, a postdoc in Johnson’s lab, is the paper’s lead author ot the paper, published in the Journal of the American Chemical Society.


Anyone Can Buy Google Glass April 15

Starting at 9 a.m. ET on April 15 anyone in the US will be able to buy Google Glass for one day. This is the first time the device has been available to the general public. So far, the face-mounted nanocomputers have been sold only to Google “Explorers,” the company’s name for early adopters. At first only developers could buy Glass, but Google slowly expanded the program to include regular people. Some were hand-picked, others applied to be Explorers through Google contests by sharing what cool projects they would do if they had Glass.

Google Glass is a wearable nanocomputer with an optical head-mounted display (OHMD). It was developed by Google with the mission of producing a mass-market ubiquitous nanocomputer.Google Glass displays information in a smartphone-like hands-free format. Wearers communicate with the Internet via natural language voice commands.