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News Article | April 17, 2017
Site: www.eurekalert.org

BROOKLYN, New York - Currently, many types of fabrics, including nylon, are made in an energy-intensive, unsustainable process that uses fossil fuel. Now, NYU Tandon School of Engineering Assistant Professor Miguel Modestino, of the Department of Chemical and Biomolecular Engineering, is proposing a method that eliminates oil from the equation, employing water, plant waste, and solar energy to deliver a material identical to the nylon now widely used in the fashion industry and in other commercial applications. Modestino and his co-researcher, Sophia Haussener of the École Polytechnique Fédéral de Lausanne (EPFL), have garnered a 2017 Global Change Award of €250,000 ($267,000) from the H&M Foundation, the non-profit arm of the retailing giant. The first such initiative by a major member of the fashion world, the Global Change challenge attracted almost 3,000 applicants this year and aims to support early innovations that can accelerate the shift to a circular and sustainable garment industry, in order to protect the planet. The awards were presented in Stockholm, Sweden, on April 5. The researchers chose to focus on nylon because of the large market for the popular polymer, which they estimate to be more than 6 million tons per year, with a value of more than $20 billion. Their proposed process uses photovoltaic arrays, which generate electricity directly from the sun, to drive the electrochemical reduction of acrylonitrile (ACN) to adiponitrile (ADN) and hydrogen (H2), which will, in turn, be synthesized into hexanediamine (HDA), one of the existing precursors to nylon. Because ACN can be derived from plant waste, only sun, water, and carbon dioxide will be required as inputs, and the new process will represent a new scheme for carbon capture, where greenhouse gases will be bound into the fabric, rather than releasing them into the air. "It is gratifying to contribute toward a zero-emissions world," Modestino said. "Once this process is tested and scaled up, there is the potential to expand the concept to other segments of the chemical industry, including the synthesis of substances like aluminum and chlorine." "Miguel Modestino takes an approach that we hope to see in every bit of research done at NYU Tandon: to create technology that can be used for the benefit of humankind," said Dean Katepalli Sreenivasan. "We are proud that the H&M Foundation recognizes the value of his hard work and vision." The NYU Tandon School of Engineering dates to 1854, the founding date for both the New York University School of Civil Engineering and Architecture and the Brooklyn Collegiate and Polytechnic Institute (widely known as Brooklyn Poly). A January 2014 merger created a comprehensive school of education and research in engineering and applied sciences, rooted in a tradition of invention and entrepreneurship and dedicated to furthering technology in service to society. In addition to its main location in Brooklyn, NYU Tandon collaborates with other schools within NYU, the country's largest private research university, and is closely connected to engineering programs at NYU Abu Dhabi and NYU Shanghai. It operates Future Labs focused on start-up businesses in downtown Manhattan and Brooklyn and an award-winning online graduate program. For more information, visit http://engineering. .


News Article | April 17, 2017
Site: www.eurekalert.org

An eco-friendly method to synthesize DNA-copper nanoflowers with high load efficiencies, low cytotoxicity, and strong resistance against nucleases has been developed by Professor Hyun Gyu Park in the Department of Chemical and Biomolecular Engineering and his collaborators. The research team successfully formed a flower-shaped nanostructure in an eco-friendly condition by using interactions between copper ions and DNA containing amide and amine groups. The resulting nanoflowers exhibit high DNA loading capacities in addition to low cytotoxicity. Flower-shaped nanocrystals called nanoflowers have gained attention for their distinct features of high surface roughness and high surface area to volume ratios. The nanoflowers have been used in many areas including catalysis, electronics, and analytical chemistry. Of late, research breakthroughs were made in the generation of hybrid inorganic-organic nanoflowers containing various enzymes as organic components. The hybridization with inorganic materials greatly enhanced enzymatic activity, stability, and durability compared to the corresponding free enzymes. Generally, the formation of protein nanocrystals requires high heat treatment so it has limitations for achieving the high loading capacities of intact DNA. The research team addressed the issue, focusing on the fact that nucleic acids with well-defined structures and selective recognition properties also contain amide and amine groups in their nucleobases. They proved that flower-like structures could be formed by using nucleic acids as a synthetic template, which paved the way to synthesize the hybrid nanoflowers containing DNA as an organic component in an eco-friendly condition. The team also confirmed that this synthetic method can be universally applied to any DNA sequences containing amide and amine groups. They said their approach is quite unique considering that the majority of previous works focused on the utilization of DNA as a linker to assemble the nanomaterials. They said the method has several advantageous features. First, the 'green' synthetic procedure doesn't involve any toxic chemicals, and shows low cytotoxicity and strong resistance against nucleases. Second, the obtained nanoflowers exhibit exceptionally high DNA loading capacities. Above all, such superior features of hybrid nanoflowers enabled the sensitive detection of various molecules including phenol, hydrogen peroxide, and glucose. DNA-copper nanoflowers showed even higher peroxidase activity than those of protein-copper nanoflowers, which may be due to the larger surface area of the flower- shaped structures, creating a greater chance for applying them in the field of sensing of detection of hydrogen peroxide. The research team expects that their research will create diverse applications in many areas including biosensors and will be further applied into therapeutic applications. Professor Park said, "The inorganic component in the hybrid nanoflowers not only exhibits low cytotoxicity, but also protects the encapsulated DNA from being cleaved by endonuclease enzymes. Using this feature, the nanostructure will be applied into developing gene therapeutic carriers." This research was co-led by Professor Moon Il Kim at Gachon University and KAIST graduate Ki Soo Park, currently a professor at Konkuk University, is the first author. The research was featured as the front cover article of the Journal of Materials Chemistry B on March 28, Issue 12, published by the Royal Society of Chemistry. The research was funded by the Mid-Career Researcher Support Program of the National Research Foundation of Korea and the Global Frontier Project of the Ministry of Science, ICT & Future Planning.


News Article | April 26, 2017
Site: www.eurekalert.org

ITHACA, N.Y. - Lithium-oxygen fuel cells boast energy density levels comparable to fossil fuels and are thus seen as a promising candidate for future transportation-related energy needs. Several roadblocks stand in the way of realizing that vision, however. They include poor rechargeability, reduced efficiency due to high overpotentials (more charge energy than discharge energy) and low specific energy. Two instabilities contribute to these roadblocks. Much of the previous work done in the lab of Lynden Archer, the James A. Friend Family Distinguished Professor of Engineering in the Robert F. Smith School of Chemical and Biomolecular Engineering (CBE) at Cornell University, has centered on one: the nucleation and growth of dendrites from one electrode to the other, which causes short-circuiting, a source of premature cell failure that invariably ends in fires. It's the other instability - the loss of battery power, also known as capacity fade - that is the focus of the lab's most recent work. Snehashis Choudhury, a doctoral student in the Archer Research Group, has come up with what Archer terms an "ingenious" answer to the problem of capacity fade. Their work is detailed in "Designer interphases for the lithium-oxygen electrochemical cell," published this month in Science Advances. Choudhury is co-first author along with Charles Wan, a chemical engineering major. Capacity fade occurs when the electrolyte, which transports charged ions from the negative electrode (anode) to the positive (cathode), reacts with the electrodes. "It starts to consume the electrodes," Choudhury said. "It forms many insulating products that impede ion transport. Over time, these build up to produce such prohibitive internal cell resistance that finally the battery fades." The problem: How do you stop one electrolyte-electrode reaction, when it's another necessary reaction between the two - the transfer of ions - that produces power? Choudhury's solution is called an artificial solid-electrolyte interphase (SEI), a material that protects the electrodes while promoting the flow of electrons from one end of the cell to the other. "Such interphases form naturally in all electrochemical cells ... and their chemo-mechanical stability is critical to the success of the graphite anode in lithium-ion batteries," Archer said. " Choudhury's approach for creating a functional designer interphase is based on bromide-containing ionic polymers (ionomers) that selectively tether to the lithium anode to form a few-nanometers-thick conductive coating that protects the electrode from degradation and fade. The SEI ionomers display three attributes that allow for increased stability during electrodeposition: protection of the anode against growth of dendrites; reduction-oxidation (redox) mediation, which reduces charge overpotentials; and the formation of a stable interphase with lithium, protecting the metal while promoting ion transport. One challenge still exists: All research-grade lithium-oxygen electrochemical cells are evaluated using pure oxygen as the active cathode material. For a commercially viable lithium-oxygen (or lithium-air, as it's also known) cell, it would need to pull oxygen out of the air, and that oxygen also contains other reactive components, such as moisture and carbon dioxide. If the inefficiencies that limit performance of lithium-oxygen fuel cells can be resolved, the exceptional energy storage options offered by the cell chemistry would be a giant step forward for electrified transportation and a revolutionary advance for autonomous robotics, Archer said. "It is telling from observations of the most advanced humanoid robots that they are always either tethered to an ultra-long electrical cable or are using something like a loud lawnmower engine to generate energy," Archer said. "Either energy source compares poorly to those found in nature. Energy storage technologies such as Li-air cells, which harness materials from the surroundings, promise to close this gap." Other contributors were Lena Kourkoutis, assistant professor and the Rebecca Q. and James C. Morgan Sesquicentennial Faculty Fellow in applied and engineering physics; CBE doctoral student Wajdi Al Sadat; Sampson Lau, Ph.D. '16; Zhengyuan Tu, doctoral student in materials science and engineering; and Michael Zachman, doctoral student in applied and engineering physics. Support for this work came from the Advanced Research Projects Agency-Energy. In addition, electron microscopy was done at the Cornell Center for Materials Research, a National Science Foundation-supported Materials Research Science and Engineering Center.


News Article | February 15, 2017
Site: www.eurekalert.org

Understanding how oil and gas molecules, water and rocks interact at the nanoscale will help make extraction of hydrocarbons through hydraulic fracturing more efficient, according to Rice University researchers. Rice engineers George Hirasaki and Walter Chapman are leading an effort to better characterize the contents of organic shale by combining standard nuclear magnetic resonance (NMR) -- the same technology used by hospitals to see inside human bodies - with molecular dynamics simulations. The work presented this month in the Journal of Magnetic Resonance details their method to analyze shale samples and validate simulations that may help producers determine how much oil and/or gas exist in a formation and how difficult they may be to extract. Oil and gas drillers use NMR to characterize rock they believe contains hydrocarbons. NMR manipulates the hydrogen atoms' nuclear magnetic moments, which can be forced to align by an applied external magnetic field. After the moments are perturbed by radio-frequency electromagnetic pulses, they "relax" back to their original orientation, and NMR can detect that. Because relaxation times differ depending on the molecule and its environment, the information gathered by NMR can help identify whether a molecule is gas, oil or water and the critical size of the pores that contain them. "This is their eyes and ears for knowing what's down there," said Hirasaki, who said NMR instruments are among several tools in the string sent downhole to "log," or gather information, about a well. In conventional reservoirs, he said, the NMR log can distinguish gas, oil and water and quantify the amounts of each contained in the pores of the rock from their relaxation times -- known as T1 and T2 -- as well as how diffuse fluids are. "If the rock is water-wet, then oil will relax at rates close to that of bulk oil, while water will have a surface-relaxation time that is a function of the pore size," Hirasaki said. "This is because water is relaxed by sites at the water/mineral interface and the ratio of the mineral surface area to water volume is larger in smaller pores. The diffusivity is inversely proportional to the viscosity of the fluid. Thus gas is easily distinguished from oil and water by measuring diffusivity simultaneously with the T2 relaxation time. "In unconventional reservoirs, both T1 and T2 relaxation times of water and oil are short and have considerable overlap," he said. "Also the T1/T2 ratio can become very large in the smallest pores. The diffusivity is restricted by the nanometer-to-micron size of the pores. Thus it is a challenge to determine if the signal is from gas, oil or water." Hirasaki said there is debate on whether the short relaxation times in shale are due to paramagnetic sites on mineral surfaces and asphaltene aggregates and/or due to the restricted motion of the molecules confined in small pores. "We don't have an answer yet, but this study is the first step," he said. "The development of technology to drill horizontal wells and apply multiple hydraulic fractures (up to about 50) is what made oil and gas production commercially viable from unconventional resources," Hirasaki said. "These resources were previously known as the 'source rock,' from which oil and gas found in conventional reservoirs had originated and migrated. The source rock was too tight for commercial production using conventional technology." Fluids pumped downhole to fracture a horizontal well contain water, chemicals and sand that keeps the fracture "propped" open after the injection stops. The fluids are then pumped out to make room for the hydrocarbons to flow. But not all the water sent downhole comes back. Often the chemical composition of the organic component of shale known as kerogen has an affinity that allows water molecules to bind and block the nanoscale pores that would otherwise let oil and gas molecules through. "Kerogen is the organic material that resisted biodegradation during deep burial," Hirasaki said. "When it gets to a certain temperature, the molecules start cracking and make hydrocarbon liquids. Higher temperature makes methane (natural gas). But the fluids are in pores that are so tight the technology developed for conventional reservoirs doesn't apply anymore." The Rice project managed by lead author Philip Singer, a research scientist in Hirasaki's lab, and co-author Dilip Asthagiri, a research scientist in Chapman's lab, a lecturer and director of Rice's Professional Master's in Chemical Engineering program, applies NMR to kerogen samples and compares it to computer models that simulate how the substances interact, particularly in terms of material's wettability, its affinity for binding to water, gas or oil molecules. "NMR is very sensitive to fluid-surface interactions," Singer said. "With shale, the complication we're dealing with is the nanoscale pores. The NMR signal changes dramatically compared with measuring conventional rocks, in which pores are larger than a micron. So to understand what the NMR is telling us in shale, we need to simulate the interactions down to the nanoscale." The simulations mimic the molecules' known relaxation properties and reveal how they move in such a restrictive environment. When matched with NMR signals, they help interpret conditions downhole. That knowledge could also lead to fracking fluids that are less likely to bind to the rock, improving the flow of hydrocarbons, Hirasaki said. "If we can verify with measurements in the laboratory how fluids in highly confined or viscous systems behave, then we'll be able to use the same types of models to describe what's happening in the reservoir itself," he said. One goal is to incorporate the simulations into iSAFT -- inhomogeneous Statistical Associating Fluid Theory -- a pioneering method developed by Chapman and his group to simulate the free energy landscapes of complex materials and analyze their microstructures, surface forces, wettability and morphological transitions. "Our results challenge approximations in models that have been used for over 50 years to interpret NMR and MRI (magnetic resonance imaging) data," Chapman said. "Now that we have established the approach, we hope to explain results that have baffled scientists for years." Chapman is the William W. Akers Professor of Chemical and Biomolecular Engineering and associate dean for energy in the George R. Brown School of Engineering. Hirasaki is the A.J. Hartsook Professor Emeritus of Chemical and Biomolecular Engineering. The Rice University Consortium on Processes in Porous Media supported the research, with computing resources supplied by the National Energy Research Scientific Computing Center, which is supported by the Office of Science of the U.S. Department of Energy, and the Texas Advanced Computing Center at the University of Texas at Austin. This news release can be found online at http://news. Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,910 undergraduates and 2,809 graduate students, Rice's undergraduate student-to-faculty ratio is 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for happiest students and for lots of race/class interaction by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger's Personal Finance. To read "What they're saying about Rice," go to http://tinyurl. .


News Article | February 15, 2017
Site: www.prweb.com

Worcester Polytechnic Institute will hold its second annual Advanced Biomanufacturing Symposium, a two-day, in-depth event that will focus on the technology and processes of continuous biomanufacturing and the challenges of making novel cell and regenerative tissue therapies that are approaching the clinic. The symposium, which was over-subscribed last year, is set for March 27–28, 2017. Organized by WPI life sciences and bioengineering faculty members and the university’s Biomanufacturing Education and Training Center (BETC), the symposium will bring together industry professionals and academic researchers working with new technologies, processes, and business practices that will have a significant impact on biomanufacturing in the near term. “2017 is shaping up to be an important year for biological products, with increasing public awareness of the industry and advances across the biomanufacturing spectrum that will demand our attention,” said Kamal Rashid, PhD, director of the BETC and research professor at WPI. “Evolving platforms and expression systems, progress towards end-to-end continuous biomanufacturing, the challenges of cell and tissue therapies—all of these topics will be explored in detail at our symposium.” This year’s keynote presenters include Manon Cox, PhD, president and chief executive officer of Protein Sciences Corp.; Jerome Ritz, MD, professor at Harvard Medical School and executive director of the Connell and O'Reilly Cell Manipulation and Gene Transfer Laboratory at Dana-Farber Cancer Institute; and Gail Naughton, PhD, chief executive officer of Histogen Inc. Of note, Kelvin Lee, PhD, Gore Professor of Chemical and Biomolecular Engineering at the University of Delaware, who led the team that organized the recently funded National Institute for Innovation in Manufacturing Biopharmaceuticals(NIIMBL), will also speak at the symposium. WPI is a member of NIIMBL. The symposium will feature session talks by subject matter experts from Biogen, Eppendorf, GE Healthcare, MilliporeSigma, Organovo, Pall Life Sciences, Sartorius Stedim Biotech, and Unum Therapeutics, as well as faculty members from Tufts University and WPI. “The talks will be presented in a single-track so participants will have access to all the content, and not have to choose between concurrent sessions,” Rashid said. “This worked very well last year. It helps maximize interaction and information exchange.” (Click here for photos from last year’s symposium. ) The symposium will take place in the Rubin Campus Center on WPI’s campus in Worcester, Mass. Registration is required and space is limited. (Click here for more event information and registration.) Funded in part by a grant from the Massachusetts Life Sciences Center, the BETC is a multi-faceted resource for the biologics industry, providing a range of hands-on customized programs. The BETC works with biomanufacturers to help them train, and retrain, their employees at a state-of-the-art center removed from their own production facilities. The center also provides research collaboration opportunities and consulting services to help companies manage challenges, explore new technologies, or scale up new processes. Founded in 1865 in Worcester, Mass., WPI is one of the nation’s first engineering and technology universities. Its 14 academic departments offer more than 50 undergraduate and graduate degree programs in science, engineering, technology, business, the social sciences, and the humanities and arts, leading to bachelor’s, master’s and doctoral degrees. WPI’s talented faculty work with students on interdisciplinary research that seeks solutions to important and socially relevant problems in fields as diverse as the life sciences and bioengineering, energy, information security, materials processing, and robotics. Students also have the opportunity to make a difference to communities and organizations around the world through the university’s innovative Global Projects Program. There are more than 45 WPI project centers throughout the Americas, Africa, Asia-Pacific, and Europe.


News Article | February 27, 2017
Site: www.eurekalert.org

Alzheimer's disease, and other neurodegenerative conditions involving abnormal folding of proteins, may help explain the emergence of life -- and how to create it. Researchers at Emory University and Georgia Tech demonstrated this connection in two new papers published by Nature Chemistry: "Design of multi-phase dynamic chemical networks" and "Catalytic diversity in self-propagating peptide assemblies." "In the first paper we showed that you can create tension between a chemical and physical system to give rise to more complex systems. And in the second paper, we showed that these complex systems can have remarkable and unexpected functions," says David Lynn, a systems chemist in Emory's Department of Chemistry who led the research. "The work was inspired by our current understanding of Darwinian selection of protein misfolding in neurodegenerative diseases." The Lynn lab is exploring ways to potentially control and direct the processes of these proteins -- known as prions -- adding to knowledge that might one day help to prevent disease, as well as open new realms of synthetic biology. For the current papers, Emory collaborated with the research group of Martha Grover, a professor in the Georgia Tech School of Chemical & Biomolecular Engineering, to develop molecular models for the processes. "Modeling requires us to formulate our hypotheses in the language of mathematics, and then we use the models to design further experiments to test the hypotheses," Grover says. Darwin's theory of evolution by natural selection is well-established -- organisms adapt over time in response to environmental changes. But theories about how life emerges -- the movement through a pre-Darwinian world to the Darwinian threshold -- remain murkier. The researchers started with single peptides and engineered in the capacity to spontaneously form small proteins, or short polymers. "These protein polymers can fold into a seemingly endless array of forms, and sometimes behave like origami," Lynn explains. "They can stack into assemblies that carry new functions, like prions that move from cell-to-cell, causing disease." This protein misfolding provided the model for how physical changes could carry information with function, a critical component for evolution. To try to kickstart that evolution, the researchers engineered a chemical system of peptides and coupled it to the physical system of protein misfolding. The combination results in a system that generates step-by-step, progressive changes, through self-driven environmental changes. "The folding events, or phase changes, drive the chemistry and the chemistry drives the replication of the protein molecules," Lynn says. "The simple system we designed requires only the initial intervention from us to achieve progressive growth in molecular order. The challenge now becomes the discovery of positive feedback mechanisms that allow the system to continue to grow." The research was funded by the McDonnell Foundation, the National Science Foundation's Materials Science Directorate, Emory University's Alzheimer's Disease Research Center, the National Science Foundation's Center for Chemical Evolution and the Office of Basic Energy Sciences of the U.S. Department of Energy. Additional co-authors of the papers include: Toluople Omosun, Seth Childers, Dibyendu Das and Anil Mehta (Emory Departments of Chemistry and Biology); Ming-Chien Hsieh (Georgia Tech School of Chemical and Biomolecular Engineering); and Neil Anthony and Keith Berland (Emory Department of Physics).


News Article | February 28, 2017
Site: phys.org

A team of engineers and scientists from the NYU Tandon School of Engineering Department of Chemical and Biomolecular Engineering, the NYU Center for Soft Matter Research, and Sungkyunkwan University School of Chemical Engineering in the Republic of Korea report they have found a pathway toward the self-assembly of these elusive photonic crystal structures never assembled before on the sub-micrometer scale (one micrometer is about 100 times smaller than the diameter of a strand of human hair). The research, which appears in the journal Nature Materials, introduces a new design principle based on preassembled components of the desired superstructure, much as a prefabricated house begins as a collection of pre-built sections. The researchers report they were able to assemble the colloidal spheres into diamond and pyrochlore crystal structures - a particularly difficult challenge because so much space is left unoccupied. The team, comprising Etienne Ducrot, a post-doctoral researcher at the NYU Center for Soft Matter Research; Mingxin He, a doctoral student in chemical and biomolecular engineering at NYU Tandon; Gi-Ra Yi of Sungkyunkwan University; and David J. Pine, chair of the Department of Chemical and Biomolecular Engineering at NYU Tandon School of Engineering and a NYU professor of physics in the NYU College of Arts and Science, took inspiration from a metal alloy of magnesium and copper that occurs naturally in diamond and pyrochlore structures as sub-lattices. They saw that these complex structures could be decomposed into single spheres and tetrahedral clusters (four spheres permanently bound). To realize this in the lab, they prepared sub-micron plastic colloidal clusters and spheres, and employed DNA segments bound to their surface to direct the self-assembly into the desired superstructure. "We are able to build those complex structures because we are not starting with single spheres as building blocks, but with pre-assembled parts already 'glued' together," Ducrot said. "We fill the structural voids of the diamond lattice with an interpenetrated structure, the pyrochlore, that happens to be as valuable as the diamond lattice for future photonic applications." Ducrot said open colloidal crystals, such as those with diamond and pyrochlore configurations, are desirable because, when composed of the right material, they may possess photonic band gaps—ranges of light frequency that cannot propagate through the structure—meaning that they could be for light what semiconductors are for electrons. "This story has been a long time in the making as those material properties have been predicted 26 years ago but until now, there was no practical pathway to build them," he said. "To achieve a band gap in the visible part of the electromagnetic spectrum, the particles need to be on the order of 150 nanometers, which is in the colloidal range. In such a material, light should travel with no dissipation along a defect, making possible the construction of chips based on light." Pine said that self-assembly technology is critical to making production of these crystals economically feasible because creating bulk quantities of crystals with lithography techniques at the correct scale would be extremely costly and very challenging. "Self-assembly is therefore a very appealing way to inexpensively create crystals with a photonic band gap in bulk quantities," Pine said. More information: Colloidal alloys with preassembled clusters and spheres, Nature Materials, DOI: 10.1038/nmat4869 , http://www.nature.com/nmat/journal/vaop/ncurrent/full/nmat4869.html


News Article | February 28, 2017
Site: www.eurekalert.org

BROOKLYN, New York - Colloidal particles, used in a range of technical applications including foods, inks, paints, and cosmetics, can self-assemble into a remarkable variety of densely-packed crystalline structures. For decades, though, researchers have been trying to coax colloidal spheres to arranging themselves into much more sparsely populated lattices in order to unleash potentially valuable optical properties. These structures, called photonic crystals, could increase the efficiency of lasers, further miniaturize optical components, and vastly increase engineers' ability to control the flow of light. A team of engineers and scientists from the NYU Tandon School of Engineering Department of Chemical and Biomolecular Engineering, the NYU Center for Soft Matter Research, and Sungkyunkwan University School of Chemical Engineering in the Republic of Korea report they have found a pathway toward the self-assembly of these elusive photonic crystal structures never assembled before on the sub-micrometer scale (one micrometer is about 100 times smaller than the diameter of a strand of human hair). The research, which appears in the journal Nature Materials, introduces a new design principle based on preassembled components of the desired superstructure, much as a prefabricated house begins as a collection of pre-built sections. The researchers report they were able to assemble the colloidal spheres into diamond and pyrochlore crystal structures - a particularly difficult challenge because so much space is left unoccupied. The team, comprising Etienne Ducrot, a post-doctoral researcher at the NYU Center for Soft Matter Research; Mingxin He, a doctoral student in chemical and biomolecular engineering at NYU Tandon; Gi-Ra Yi of Sungkyunkwan University; and David J. Pine, chair of the Department of Chemical and Biomolecular Engineering at NYU Tandon School of Engineering and a NYU professor of physics in the NYU College of Arts and Science, took inspiration from a metal alloy of magnesium and copper that occurs naturally in diamond and pyrochlore structures as sub-lattices. They saw that these complex structures could be decomposed into single spheres and tetrahedral clusters (four spheres permanently bound). To realize this in the lab, they prepared sub-micron plastic colloidal clusters and spheres, and employed DNA segments bound to their surface to direct the self-assembly into the desired superstructure. "We are able to build those complex structures because we are not starting with single spheres as building blocks, but with pre-assembled parts already 'glued' together," Ducrot said. "We fill the structural voids of the diamond lattice with an interpenetrated structure, the pyrochlore, that happens to be as valuable as the diamond lattice for future photonic applications." Ducrot said open colloidal crystals, such as those with diamond and pyrochlore configurations, are desirable because, when composed of the right material, they may possess photonic band gaps -- ranges of light frequency that cannot propagate through the structure -- meaning that they could be for light what semiconductors are for electrons. "This story has been a long time in the making as those material properties have been predicted 26 years ago but until now, there was no practical pathway to build them," he said. "To achieve a band gap in the visible part of the electromagnetic spectrum, the particles need to be on the order of 150 nanometers, which is in the colloidal range. In such a material, light should travel with no dissipation along a defect, making possible the construction of chips based on light." Pine said that self-assembly technology is critical to making production of these crystals economically feasible because creating bulk quantities of crystals with lithography techniques at the correct scale would be extremely costly and very challenging. "Self-assembly is therefore a very appealing way to inexpensively create crystals with a photonic band gap in bulk quantities," Pine said. This research was funded by the U.S. Army Research Office under a Multidisciplinary University Research Initiative (MURI) grant. About the New York University Tandon School of Engineering The NYU Tandon School of Engineering dates to 1854, the founding date for both the New York University School of Civil Engineering and Architecture and the Brooklyn Collegiate and Polytechnic Institute (widely known as Brooklyn Poly). A January 2014 merger created a comprehensive school of education and research in engineering and applied sciences, rooted in a tradition of invention and entrepreneurship and dedicated to furthering technology in service to society. In addition to its main location in Brooklyn, NYU Tandon collaborates with other schools within NYU, the country's largest private research university, and is closely connected to engineering programs at NYU Abu Dhabi and NYU Shanghai. It operates Future Labs focused on start-up businesses in downtown Manhattan and Brooklyn and an award-winning online graduate program. For more information, visit http://engineering. .


While several circulatory system models are used today in an attempt to better understand blood flow, they still don't account for the complex rheological behavior of blood. Because blood is a complex suspension of red and white blood cells and platelets suspended within a plasma that contains various proteins, it can exhibit complex flow behavior. Many of the models currently used ignore these complexities and assume a Newtonian behavior or a constant thickness. During the 88th Annual Meeting of The Society of Rheology, being held Feb. 12-16, in Tampa, Florida, Jeffrey S. Horner, a doctoral candidate who works in both the Beris and Wagner Research Groups in the Department of Chemical and Biomolecular Engineering at the University of Delaware, will present a new approach. "Our research team aims to explore and model these non-Newtonian characteristics of blood flow through careful, well-documented measurements, and by combining expertise within the fields of rheology, computational modeling, and biology," Horner said. The goal is to identify key components of blood that directly affect the flow behavior. "We hope that eventually rheology can be used as a diagnostics tool to detect early signs for cardiovascular disease as well as various other blood diseases," he said. This work is a significant departure from previous efforts within the field of blood rheology. "Our experiments are among the first to provide reliable data that properly preconditions the sample and reports the full physiological parameters that affect flow behavior—all of which are conducted using state-of-the-art rheological equipment," noted Horner. The team is also implementing transient tests that, to their knowledge, have never been conducted on blood samples before and are designed to explore the flow regimes that occur in the human body. "The modeling we're doing of transient blood flows is thought to be the first successful effort to represent more than just the steady shear behavior of human blood," Horner said. Once transient behavior is understood and correlated to the physiological parameters within the blood, "we can then use rheology as a diagnostic tool for human blood," added Horner. "As a diagnostic tool, it will enable earlier and quicker detection of various diseases." Explore further: New models for validating computational simulations of blood flow and damage in medical devices More information: Investigation of the human blood rheology in transient flows. www.rheology.org/SoR172/ViewPaper?ID=161


News Article | February 10, 2017
Site: www.biosciencetechnology.com

Research by Professor of Chemical and Biomolecular Engineering Huimin Zhao and graduate student Behnam Enghiad at the University of Illinois is pioneering a new method of genetic engineering for basic and applied biological research and medicine. Their work, reported in ACS Synthetic Biology on February 6, has the potential to open new doors in genomic research by improving the precision and adherence of sliced DNA. "Using our technology, we can create highly active artificial restriction enzymes with virtually any sequence specificity and defined sticky ends of varying length," said Zhao, who leads a synthetic biology research group at the Carl R. Woese Institute for Genomic Biology at Illinois. "This is a rare example in biotechnology where a desired biological function or reagent can be readily and precisely designed in a rational manner." Restriction enzymes are an important tool in genomic research: by cutting DNA at a specific site, they create a space wherein foreign DNA can be introduced for gene-editing purposes. This process is not only achieved by naturally-occurring restriction enzymes; other artificial restriction enzymes, or AREs, have risen to prominence in recent years. CRISPR-Cas9, a bacterial immune system used for "cut-and-paste" gene editing, and TALENs, modified restriction enzymes, are two popular examples of such techniques. Though useful in genetic engineering, no AREs generate defined "sticky ends"--an uneven break in the DNA ladder-structure that leaves complementary overhangs, improving adhesion when introducing new DNA. "If you can cleave two different DNA samples with the same restriction enzyme, the sticky ends that are generated are complementary," explained Enghiad. "They will hybridize with each other, and if you use a ligase, you can stick them together." However, restriction enzymes themselves have a critical drawback: the recognition sequence which prompts them to cut is very short--usually only four to eight base pairs. Because the enzymes will cut anywhere that sequence appears, researchers rely on finding a restriction enzyme whose cut site appears only once in the genome of their organism or plasmid--an often difficult proposition when the DNA at hand might be thousands of base pairs long. This problem has been partially solved simply by the sheer number of restriction enzymes discovered: more than 3600 have been characterized, and over 250 are commercially available. "Just in our freezer, for our other research, we have probably over 100 different restriction enzymes," said Enghiad. "We look through them all whenever we want to assemble something ... the chance of finding the unique restriction site is so low. "Our new technology unifies all of those restriction enzymes into a single system consisting of one protein and two DNA guides. Not only have you replaced them, but you can now target sites that no available restriction enzymes can." Enghiad and Zhao's new technique creates AREs through the use of an Argonaute protein (PfAgo) taken from Pyrococcus furiosus, an archeal species. Led by a DNA guide, PfAgo is able to recognize much longer sequences when finding its cut site, increasing specificity and removing much of the obstacles posed by restriction enzymes. Further, PfAgo can create longer sticky ends than even restriction enzymes, a substantial benefit as compared to other AREs. "When we started, I was inspired by a paper about a related protein--TtAgo. It could use a DNA guide to cleave DNA, but only up to 70 degrees," explained Enghiad. "DNA strands start to separate over 75 degrees, which could allow a protein to create sticky ends. If there were a protein that was active at higher temperatures, I reasoned, that protein could be used as an artificial restriction enzyme. "So I started looking for that, and what I found was PfAgo." In addition to replacing restriction enzymes in genetic engineering processes, Enghiad and Zhao believe their technology will have broad applications in the biological research. By creating arbitrary sticky ends, PfAgo could make assembly of large DNA molecules easier, and enables cloning of large DNA molecules such as biochemical pathways and large genes. The application of these techniques is broad-reaching: ranging from discovery of new small molecule drugs to engineering of microbial cell factories for synthesis of fuels and chemicals to molecular diagnostics of genetic diseases and pathogens, which are the areas Zhao and Enghiad are currently exploring. "Due to its unprecedented simplicity and programmability (a single protein plus DNA guides for targeting), as well as accessibility ... we expect PfAgo-based AREs will become a powerful and indispensable tool in all restriction enzyme or nuclease-enabled biotechnological applications and fundamental biological research," said Zhao. "It is to molecular biology as the CRISPR technology is to cell biology."

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