ACS Nano

A Phone That Charges in Seconds? UCF Scientists Bring it Closer to Reality

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A Phone That Charges in Seconds? UCF Scientists Bring it Closer to Reality

A team of UCF scientists has developed a new process for creating flexible supercapacitors that can store more energy and be recharged more than 30,000 times without degrading.

The novel method from the University of Central Florida’s NanoScience Technology Center could eventually revolutionize technology as varied as mobile phones and electric vehicles.

“If they were to replace the batteries with these supercapacitors, you could charge your mobile phone in a few seconds and you wouldn’t need to charge it again for over a week,” said Nitin Choudhary, a postdoctoral associate who conducted much of the research published recently in the academic journalACS Nano.

Anyone with a smartphone knows the problem: After 18 months or so, it holds a charge for less and less time as the battery begins to degrade.

Scientists have been studying the use of nanomaterials to improve supercapacitors that could enhance or even replace batteries in electronic devices. It’s a stubborn problem, because a supercapacitor that held as much energy as a lithium-ion battery would have to be much, much larger.

The team at UCF has experimented with applying newly discovered two-dimensional materials only a few atoms thick to supercapacitors. Other researchers have also tried formulations with graphene and other two-dimensional materials, but with limited success.

“There have been problems in the way people incorporate these two-dimensional materials into the existing systems – that’s been a bottleneck in the field. We developed a simple chemical synthesis approach so we can very nicely integrate the existing materials with the two-dimensional materials,” said principal investigator Yeonwoong “Eric” Jung, an assistant professor with joint appointments to the NanoScience Technology Center and the Materials Science & Engineering Department.

Jung’s team has developed supercapacitors composed of millions of nanometer-thick wires coated with shells of two-dimensional materials. A highly conductive core facilitates fast electron transfer for fast charging and discharging. And uniformly coated shells of two-dimensional materials yield high energy and power densities.

Scientists already knew two-dimensional materials held great promise for energy storage applications. But until the UCF-developed process for integrating those materials, there was no way to realize that potential, Jung said.

“For small electronic devices, our materials are surpassing the conventional ones worldwide in terms of energy density, power density and cyclic stability,” Choudhary said.

Cyclic stability defines how many times it can be charged, drained and recharged before beginning to degrade. For example, a lithium-ion battery can be recharged fewer than 1,500 times without significant failure. Recent formulations of supercapacitors with two-dimensional materials can be recharged a few thousand times.

By comparison, the new process created at UCF yields a supercapacitor that doesn’t degrade even after it’s been recharged 30,000 times.

Jung is working with UCF’s Office of Technology Transfer to patent the new process.

Supercapacitors that use the new materials could be used in phones and other electronic gadgets, and electric vehicles that could benefit from sudden bursts of power and speed. And because they’re flexible, it could mean a significant advancement in wearable tech, as well.

“It’s not ready for commercialization,” Jung said. “But this is a proof-of-concept demonstration, and our studies show there are very high impacts for many technologies.”

In addition to Choudhary and Jung, the research team included Chao Li, Julian Moore and Associate Professor Jayan Thomas, all of the UCF NanoScience Technology Center; and Hee-Suk Chung of Korea Basic Science Institute in Jeonju, South Korea.

Source: ucf.edu

 

DNA clamp to grab cancer before it develops.

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As part of an international research project, a team of researchers has developed a DNA clamp that can detect mutations at the DNA level with greater efficiency than methods currently in use. Their work could facilitate rapid screening of those diseases that have a genetic basis, such as cancer, and provide new tools for more advanced nanotechnology. The results of this research is published this month in the journal ACS Nano.

Toward a new generation of screening tests

An increasing number of genetic mutations have been identified as risk factors for the development of cancer and many other diseases. Several research groups have attempted to develop rapid and inexpensive screening methods for detecting these mutations. “The results of our study have considerable implications in the area of diagnostics and therapeutics,” says Professor Francesco Ricci, “because the DNA clamp can be adapted to provide a fluorescent signal in the presence of DNA sequences having mutations with high risk for certain types cancer. The advantage of our fluorescence clamp, compared to other detection methods, is that it allows distinguishing between mutant and non-mutant DNA with much greater efficiency. This information is critical because it tells patients which cancer(s) they are at risk for or have.”

“Nature is a constant source of inspiration in the development of technologies,” says Professor Alexis Vallée-Bélisle. “For example, in addition to revolutionizing our understanding of how life works, the discovery of the DNA double helix by Watson, Crick and Franklin in 1953 also inspired the development of many diagnostic tests that use the strong affinity between two complementary DNA strands to detect mutations.”

“However, it is also known that DNA can adopt many other architectures, including triple helices, which are obtained in DNA sequences rich in purine (A, G) and pyrimidine (T, C) bases,” says the researcher Andrea Idili, first author of the study. “Inspired by these natural triple helices, we developed a DNA-based clamp to form a triple helix whose specificity is ten times greater than a double helix allows.”

“Beyond the obvious applications in the diagnosis of genetic diseases, I believe this work will pave the way for new applications related in the area of DNA-based nanostructures and nanomachines,” notes Professor Kevin Plaxco, University of California, Santa Barbara. “Such nanomachines could ultimately have a major impact on many aspects of healthcare in the future.”

“The next step is to test the clamp on human samples, and if it is successful, it will begin the process of commercialization,” concludes Professor Vallée-Bélisle.

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Artist’s rendering of the discovery: the research team took advantage of the ability of certain DNA sequences to form a triple helix, in order to develop a DNA clamp. This nanometer-scale clamp recognizes and binds DNA sequences more strongly and more specifically, allowing the development of more effective diagnostic. Professor Alexis Vallée-Bélisle, Department of Chemistry, Université de Montréal worked with the researcher Andrea Idili and Professor Francesco Ricci of the University of Rome Tor Vergata, and Professor Kevin W. Plaxco, University of California Santa Barbara, to develop this diagnostic nanomachine

What can a graphene sandwich reveal about proteins?

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Stronger than steel, but only one atom thick – latest research using the 2D miracle material graphene could be the key to unlocking the mysteries around the structure and behaviour of proteins in the very near future.

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Scientists at The University of Manchester and the SuperSTEM facility, which is located at STFC’s Daresbury Laboratory and funded by the Engineering and Physical Sciences Research Council (EPSRC), have discovered that the most fragile, microscopic materials can be protected from the harmful effects of radiation when under the microscope if they are ‘sandwiched’ between two sheets of . The technique could soon be the key to enabling the direct study of every single individual atom in a , something yet to be achieved, and revolutionise our understanding of cell structure, how the immune system reacts to viruses and aid in the design of new antiviral drugs.

Observing the structure of some the tiniest of objects, such as proteins and other sensitive 2D materials, at the atomic scale requires a powerful electron microscope. This is exceptionally difficult because the radiation from the can destroy the highly fragile object being imaged before any useful data can be accurately recorded. However, by protecting fragile objects between two sheets of graphene it means they can be imaged for longer without damage under the electron beam, making it possible to quantitatively identify every single atom within the structure. This technique has proven very successful on the test case of a fragile in-organic 2D crystal and the results published in the journal ACS Nano.

During this research, the team of scientists, which included Sir Kostya Novoselov, who shared a Nobel Prize in Physics in 2010 for exploiting the remarkable properties of graphene, were able to observe the effects of encapsulating a microscopic crystal of another highly fragile 2D material, molybdenum di-sulfide, between two sheets of graphene. They found that they were able to apply a high electron beam to directly image, identify and obtain complete chemical analysis of each and every atom within the molybdenum di-sulfide sheet, without causing any defects to the material through radiation.

The University of Manchester’s Dr Recep Zan, who led the research team, said: “Graphene is a million times thinner than paper, yet stronger than steel, with fantastic potential in areas from electronics to energy. But this research shows its potential in biochemistry could also be just as significant, and could eventually open up all sorts of applications in the biotechnology arena.”

Professor Quentin Ramasse, Scientific Director at SuperSTEM added: “What this research demonstrates is not so much about graphene itself, but how it can impact the detail and accuracy at which we can directly study other inorganic 2D materials or highly fragile molecules. Until now this has mostly been possible through less direct and often complicated methods such as protein crystallography which do not provide a direct visualisation of the object in question. This new capability is particularly exciting because it could pave the way to being able to image every single atom in a protein chain for example, something which could significantly impact our development of treatments for conditions such as cancer, Alzheimer’s and HIV.”

Nanomedicine: Particle physiology

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Particles deliver cancer drugs.

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UNSW chemical engineers have synthesised a new iron oxide nanoparticle that delivers cancer drugs to cells while simultaneously monitoring the drug release in real time.

The result, published online in the journal ACS Nano, represents an important development for the emerging field of theranostics – a term that refers to nanoparticles that can treat and diagnose disease.

“Iron oxide nanoparticles that can track drug delivery will provide the possibility to adapt treatments for individual patients,” says Associate Professor Cyrille Boyer from the UNSW School of Chemical Engineering.

By understanding how the cancer drug is released and its effect on the cells and surrounding tissue, doctors can adjust doses to achieve the best result.

Importantly, Boyer and his team demonstrated for the first time the use of a technique called fluorescence lifetime imaging to monitor the drug release inside a line of lung cancer cells.

“Usually, the drug release is determined using model experiments on the lab bench, but not in the cells,” says Boyer. “This is significant as it allows us to determine the kinetic movement of drug release in a true biological environment.”

Magnetic iron oxide nanoparticles have been studied widely because of their applications as contrast agents in magnetic resonance imaging, or MRI. Several recent studies have explored the possibility of equipping these contrast agents with drugs.

However, there are limited studies describing how to load chemotherapy drugs onto the surface of magnetic iron oxide nanoparticles, and no studies that have effectively proven that these drugs can be delivered inside the cell. This has only been inferred.

With this latest study, the UNSW researchers engineered a new way of loading the drugs onto the nanoparticle’s polymer surface, and demonstrated for the first time that the particles are delivering their drug inside the cells.

“This is very important because it shows that bench chemistry is working inside the cells,” says Boyer. “The next step in the research is to move to in-vivo applications.”

Simple urine test uses nanotechnology to detect dangerous blood clotting

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Life-threatening blood clots can form in anyone who sits on a plane for a long time, is confined to bed while recovering from surgery, or takes certain medications.

There is no fast and easy way to diagnose these clots, which often remain undetected until they break free and cause a stroke or heart attack. However, new technology from MIT may soon change that: A team of engineers has developed a way to detect blood clots using a simple urine test.

The noninvasive diagnostic, described in a recent issue of the journal ACS Nano, relies on  that detect the presence of , a key  factor.

Such a system could be used to monitor patients who are at high risk for blood clots, says Sangeeta Bhatia, senior author of the paper and the John and Dorothy Wilson Professor of Biochemistry.

“Some patients are at more risk for clotting, but existing blood tests are not consistently able to detect the formation of new clots,” says Bhatia, who is also a senior associate member of the Broad Institute and a member of MIT’s Koch Institute for Integrative Cancer Research and Institute for Medical Engineering and Science (IMES).

Lead authors of the paper are Kevin Lin, a graduate student in chemical engineering, and Gabriel Kwong, a postdoc in IMES. Other authors are Andrew Warren, a graduate student in Health Sciences and Technology (HST), and former HST postdoc David Wood.

Sensing thrombin

Blood clotting is produced by a complex cascade of protein interactions, culminating in the formation of fibrin, a fibrous protein that seals wounds. The last step of this process—the conversion of fibrinogen to fibrin—is controlled by an enzyme called thrombin.

Current tests for blood clotting are very indirect, Bhatia says. One, known as the D-dimer test, looks for the presence of fibrin byproducts, which indicates that a clot is being broken down, but will not detect its initial formation.

Bhatia and her colleagues developed their new test based on a technology they first reported last year for early detection of colorectal cancer. “We realized the same exact technology would work for blood clots,” she says. “So we took the test we had developed before, which is an injectable nanoparticle, and made it a thrombin sensor.”

Finding blood clots before they wreak havoc

The system consists of , which the Food and Drug Administration has approved for human use, coated with peptides (short proteins) that are specialized to interact with thrombin. After being injected into mice, the nanoparticles travel throughout the body. When the particles encounter thrombin, the thrombin cleaves the peptides at a specific location, releasing fragments that are then excreted in the animals’ urine.

Once the urine is collected, the protein fragments can be identified by treating the sample with antibodies specific to peptide tags included in the fragments. The researchers showed that the amount of these tags found in the urine is directly proportional to the level of blood clotting in the mice’s lungs.

In the previous version of the system, reported last December in Nature Biotechnology, the researchers used mass spectrometry to distinguish the fragments by their mass. However, testing samples with antibodies is much simpler and cheaper, the researchers say.

Rapid screening

Bhatia says she envisions two possible applications for this kind of test. One is to screen patients who come to the emergency room complaining of symptoms that might indicate a blood clot, allowing doctors to rapidly triage such patients and determine if more tests are needed.

“Right now they just don’t know how to efficiently define who to do the more extensive workup on. It’s one of those things that you can’t afford to miss, so patients can get an unnecessarily expensive workup,” Bhatia says.

Another application is monitoring patients who are at high risk for a clot—for example, people who have to spend a lot of time in bed recovering from surgery. Bhatia is working on a urine dipstick test, similar to a pregnancy , that doctors could give  when they go home after surgery.

“If a patient is at risk for thrombosis, you could send them home with a 10-pack of these sticks and say, ‘Pee on this every other day and call me if it turns blue,'” she says.

The technology could also be useful for predicting recurrence of clots, says Henri Spronk, an assistant professor of biochemistry at Maastricht University in the Netherlands.

“High levels of activation markers have been related to recurrent thrombosis, but they don’t have good sensitivity or specificity. Through application of the nanoparticles, if proven well-tolerated and nontoxic, alterations in the normal low levels of physiological thrombin generation might be easily detected,” says Spronk, who was not part of the research team.

Bhatia plans to launch a company to commercialize the technology, with funding from MIT’s Deshpande Center for Technological Innovation. Other applications for the nanoparticle system could include monitoring and diagnosing cancer. It could also be adapted to track liver, pulmonary, and kidney fibrosis, Bhatia says.