Light-activated Nanoparticles (Quantum Dots) can supercharge current antibiotics


QDs and Antibiotics CU 171004142650_1_540x360CU Boulder researcher Colleen Courtney (left) speaks with Assistant Professor Anushree Chatterjee (right) inside a lab in the BioFrontiers Institute.
Credit: University of Colorado Boulder

Light-activated nanoparticles, also known as quantum dots, can provide a crucial boost in effectiveness for antibiotic treatments used to combat drug-resistant superbugs such as E. coliand Salmonella, new University of Colorado Boulder research shows.

Multi-drug resistant pathogens, which evolve their defenses faster than new antibiotic treatments can be developed to treat them, cost the United States an estimated $20 billion in direct healthcare costs and an additional $35 billion in lost productivity in 2013.

CU Boulder researchers, however, were able to re-potentiate existing antibiotics for certain clinical isolate infections by introducing nano-engineered quantum dots, which can be deployed selectively and activated or de-activated using specific wavelengths of light.

Rather than attacking the infecting bacteria conventionally, the dots release superoxide, a chemical species that interferes with the bacteria’s metabolic and cellular processes, triggering a fight response that makes it more susceptible to the original antibiotic.

“We’ve developed a one-two knockout punch,” said Prashant Nagpal, an assistant professor in CU Boulder’s Department of Chemical and Biological Engineering (CHBE) and the co-lead author of the study. “The bacteria’s natural fight reaction [to the dots] actually leaves it more vulnerable.”

The findings, which were published today in the journal Science Advances, show that the dots reduced the effective antibiotic resistance of the clinical isolate infections by a factor of 1,000 without producing adverse side effects.

“We are thinking more like the bug,” said Anushree Chatterjee, an assistant professor in CHBE and the co-lead author of the study. “This is a novel strategy that plays against the infection’s normal strength and catalyzes the antibiotic instead.”

While other previous antibiotic treatments have proven too indiscriminate in their attack, the quantum dots have the advantage of being able to work selectively on an intracellular level. Salmonella, for example, can grow and reproduce inside host cells. The dots, however, are small enough to slip inside and help clear the infection from within.

“These super-resistant bugs already exist right now, especially in hospitals,” said Nagpal. “It’s just a matter of not contracting them. But they are one mutation away from becoming much more widespread infections.”

Overall, Chatterjee said, the most important advantage of the quantum dot technology is that it offers clinicians an adaptable multifaceted approach to fighting infections that are already straining the limits of current treatments.

“Disease works much faster than we do,” she said. “Medicine needs to evolve as well.”

Going forward, the researchers envision quantum dots as a kind of platform technology that can be scaled and modified to combat a wide range of infections and potentially expand to other therapeutic applications.

Story Source:

Materials provided by University of Colorado at Boulder. Original written by Trent Knoss. Note: Content may be edited for style and length.


Journal Reference:

  1. Colleen M. Courtney, Samuel M. Goodman, Toni A. Nagy, Max Levy, Pallavi Bhusal, Nancy E. Madinger, Corrella S. Detweiler, Prashant Nagpal, and Anushree Chatterjee. Potentiating antibiotics in drug-resistant clinical isolates via stimuli-activated superoxide generationScience Advances, 04 Oct 2017 DOI: 10.1126/sciadv.1701776
Advertisements

University of Colorado:Engineers transform brewery wastewater into energy storage … Only in Colorado … Only in Boulder would …


colorado-brewery-engineerstraEquipment at a brewery. Credit: FTGallo / Wikipedia.

 

University of Colorado Boulder engineers have developed an innovative bio-manufacturing process that uses a biological organism cultivated in brewery wastewater to create the carbon-based materials needed to make energy storage cells.

This unique pairing of breweries and batteries could set up a win-win opportunity by reducing expensive wastewater treatment costs for beer makers while providing manufacturers with a more cost-effective means of creating renewable, naturally-derived fuel cell technologies.

“Breweries use about seven barrels of water for every barrel of beer produced,” said Tyler Huggins, a graduate student in CU Boulder’s Department of Civil, Environmental and Architectural Engineering and lead author of the new study. “And they can’t just dump it into the sewer because it requires extra filtration.”

The process of converting biological materials, or biomass, such as timber into carbon-based battery electrodes is currently used in some energy industry sectors. But, naturally-occurring biomass is inherently limited by its short supply, impact during extraction and intrinsic chemical makeup, rendering it expensive and difficult to optimize.

However, the CU Boulder researchers utilize the unsurpassed efficiency of biological systems to produce sophisticated structures and unique chemistries by cultivating a fast-growing fungus, Neurospora crassa, in the sugar-rich wastewater produced by a similarly fast-growing Colorado industry: breweries.

“The wastewater is ideal for our fungus to flourish in, so we are happy to take it,” said Huggins.

By cultivating their feedstock in wastewater, the researchers were able to better dictate the fungus’s chemical and physical processes from the start. They thereby created one of the most efficient naturally-derived lithium-ion battery electrodes known to date while cleaning the wastewater in the process.

The findings were published recently in the American Chemical Society journal Applied Materials & Interfaces.

If the process were applied on a large scale, breweries could potentially reduce their municipal wastewater costs significantly while manufacturers would gain access to a cost-effective incubating medium for advanced battery technology components.

“The novelty of our process is changing the manufacturing process from top-down to bottom-up,” said Zhiyong Jason Ren, an associate professor in CU Boulder’s Department of Civil, Environmental and Architectural Engineering and a co-author of the new study. “We’re biodesigning the materials right from the start.”

Huggins and study co-author Justin Whiteley, also of CU Boulder, have filed a patent on the process and created Emergy, a Boulder-based company aimed at commercializing the technology.

“We see large potential for scaling because there’s nothing required in this process that isn’t already available,” said Huggins.

The researchers have partnered with Avery Brewing in Boulder in order to explore a larger pilot program for the technology. Huggins and Whiteley recently competed in the finals of a U.S. Department of Energy-sponsored startup incubator competition at the Argonne National Laboratory in Chicago, Illinois.

“This research speaks to the spirit of entrepreneurship at CU Boulder,” said Ren, who plans to continue experimenting with the mechanisms and properties of the fungus growth within the wastewater. “It’s great to see students succeeding and creating what has the potential to be a transformative technology. Energy storage represents a big opportunity for the state of Colorado and beyond.”cu-boulder-maxresdefault

Explore further: Researchers use wastewater treatment to capture CO2, produce energy

More information: Tyler M. Huggins et al. Controlled Growth of Nanostructured Biotemplates with Cobalt and Nitrogen Codoping as a Binderless Lithium-Ion Battery Anode, ACS Applied Materials & Interfaces (2016). DOI: 10.1021/acsami.6b09300

 

Nanotrees Harvest the Sun’s Energy to Turn Water into Hydrogen Fuel


 

University of California, San Diego electrical engineers are building a forest of tiny nanowire trees in order to cleanly capture solar energy without using fossil fuels and harvest it for hydrogen fuel generation. Reporting in the journal Nanoscale, the team said nanowires, which are made from abundant natural materials like silicon and zinc oxide, also offer a cheap way to deliver hydrogen fuel on a mass scale.

“This is a clean way to generate clean fuel,” said Deli Wang, professor in the Department of Electrical and Computer Engineering at the UC San Diego Jacobs School of Engineering.
The trees’ vertical structure and branches are keys to capturing the maximum amount of solar energy, according to Wang. That’s because the vertical structure of trees grabs and adsorbs light while flat surfaces simply reflect it, Wang said, adding that it is also similar to retinal photoreceptor cells in the human eye. In images of Earth from space, light reflects off of flat surfaces such as the ocean or deserts, while forests appear darker.
Wang’s team has mimicked this structure in their “3D branched nanowire array” which uses a process called photoelectrochemical water-splitting to produce hydrogen gas. Water splitting refers to the process of separating water into oxygen and hydrogen in order to extract hydrogen gas to be used as fuel. This process uses clean energy with no green-house gas byproduct. By comparison, the current conventional way of producing hydrogen relies on electricity from fossil fuels.

Schematic shows the light trapping effect in nanowire arrays. Photons on are bounced between single nanowires and eventually absorbed by them (R). By harvesting more sun light using the vertical nanotree structure, Wang’s team has developed a way to produce more hydrogen fuel efficiently compared to planar counterparts where they are reflected off the surface (L). Image Credit: Wang Research Group, UC San Diego Jacobs School of Engineering.
“Hydrogen is considered to be clean fuel compared to fossil fuel because there is no carbon emission, but the hydrogen currently used is not generated cleanly,” said Ke Sun, a PhD student in electrical engineering who led the project.
By harvesting more sun light using the vertical nanotree structure, Wang’s team has developed a way to produce more hydrogen fuel efficiently compared to planar counterparts. Wang is also affiliated with the California Institute of Telecommunications and Information Technology and the Material Science and Engineering Program at UC San Diego.
The vertical branch structure also maximizes hydrogen gas output, said Sun. For example, on the flat wide surface of a pot of boiling water, bubbles must become large to come to the surface. In the nanotree structure, very small gas bubbles of hydrogen can be extracted much faster. “Moreover, with this structure, we have enhanced, by at least 400,000 times, the surface area for chemical reactions,” said Sun.

In this experiment, nanotree electrodes are submersed in water and illuminated by simulated sun light to measure electricity output of the device. Photo credit: Joshua Knoff, UC San Diego Jacobs School of Engineering.
In the long run, what Wang’s team is aiming for is even bigger: artificial photosynthesis. In photosynthesis, as plants absorb sunlight they also collect carbon dioxide (CO2) and water from the atmosphere to create carbohydrates to fuel their own growth. Wang’s team hopes to mimic this process to also capture CO2 from the atmosphere, reducing carbon emissions, and convert it into hydrocarbon fuel.
“We are trying to mimic what the plant does to convert sunlight to energy,” said Sun. “We are hoping in the near future our ‘nanotree’ structure can eventually be part of an efficient device that functions like a real tree for photosynthesis.”
The team is also studying alternatives to zinc oxide, which absorbs the sun’s ultraviolet light, but has stability issues that affect the lifetime usage of the nanotree structure.

 

Radically new water splitting technique to produce hydrogen fuel


3adb215 D Burris(Nanowerk News) A University of Colorado Boulder team  has developed a radically new technique that uses the power of sunlight to  efficiently split water into its components of hydrogen and oxygen, paving the  way for the broad use of hydrogen as a clean, green fuel. The CU-Boulder team  has devised a solar-thermal system in which sunlight could be concentrated by a  vast array of mirrors onto a single point atop a central tower up to several  hundred feet tall. The tower would gather heat generated by the mirror system to  roughly 2,500 degrees Fahrenheit (1,350 Celsius), then deliver it into a reactor  containing chemical compounds known as metal oxides, said CU-Boulder Professor  Alan Weimer, research group leader.

imagesCAMR5BLR Einstein Judging a Fish

As a metal oxide compound heats up, it releases oxygen atoms,  changing its material composition and causing the newly formed compound to seek  out new oxygen atoms, said Weimer. The team showed that the addition of steam to  the system — which could be produced by boiling water in the reactor with the  concentrated sunlight beamed to the tower — would cause oxygen from the water  molecules to adhere to the surface of the metal oxide, freeing up hydrogen  molecules for collection as hydrogen gas.
solar thermal plant
An  artist’s conception of a commercial hydrogen production plant that uses sunlight  to split water in order to produce clean hydrogen fuel. (Image courtesy  University of Colorado Boulder)   
“We have designed something here that is very different from  other methods and frankly something that nobody thought was possible before,”  said Weimer of the chemical and biological engineering department. “Splitting  water with sunlight is the Holy Grail of a sustainable hydrogen economy.”
A paper on the subject was published in the Aug. 2 issue of  Science (“Efficient Generation of H2 by Splitting Water with an Isothermal Redox Cycle  “). The team included co-lead authors Weimer and Associate Professor Charles  Musgrave, first author and doctoral student Christopher Muhich, postdoctoral  researcher Janna Martinek, undergraduate Kayla Weston, former CU graduate  student Paul Lichty, former CU postdoctoral researcher Xinhua Liang and former  CU researcher Brian Evanko.
One of the key differences between the CU method and other  methods developed to split water is the ability to conduct two chemical  reactions at the same temperature, said Musgrave, also of the chemical and  biological engineering department. While there are no working models,  conventional theory holds that producing hydrogen through the metal oxide  process requires heating the reactor to a high temperature to remove oxygen,  then cooling it to a low temperature before injecting steam to re-oxidize the  compound in order to release hydrogen gas for collection.
“The more conventional approaches require the control of both  the switching of the temperature in the reactor from a hot to a cool state and  the introduction of steam into the system,” said Musgrave. “One of the big  innovations in our system is that there is no swing in the temperature. The  whole process is driven by either turning a steam valve on or off.”
“Just like you would use a magnifying glass to start a fire, we  can concentrate sunlight until it is really hot and use it to drive these  chemical reactions,” said Muhich. “While we can easily heat it up to more than  1,350 degrees Celsius, we want to heat it to the lowest temperature possible for  these chemical reactions to still occur. Hotter temperatures can cause rapid  thermal expansion and contraction, potentially causing damage to both the  chemical materials and to the reactors themselves.”
Lund
A  laboratory model of a multi-tube solar reactor at the University of Colorado  Boulder that can be used to split water in order to produce clean hydrogen fuel.  (Photo courtesy University of Colorado Boulder)
In addition, the two-step conventional idea for water splitting  also wastes both time and heat, said Weimer, also a faculty member at  CU-Boulder’s BioFrontiers Institute. “There are only so many hours of sunlight  in a day,” he said.
The research was supported by the National Science Foundation  and by the U.S. Department of Energy.
With the new CU-Boulder method, the amount of hydrogen produced  for fuel cells or for storage is entirely dependent on the amount of metal oxide  — which is made up of a combination of iron, cobalt, aluminum and oxygen — and  how much steam is introduced into the system. One of the designs proposed by the  team is to build reactor tubes roughly a foot in diameter and several feet long,  fill them with the metal oxide material and stack them on top of each other. A  working system to produce a significant amount of hydrogen gas would require a  number of the tall towers to gather concentrated sunlight from several acres of  mirrors surrounding each tower.
Weimer said the new design began percolating within the team  about two years ago. “When we saw that we could use this simpler, more effective  method, it required a change in our thinking,” said Weimer. “We had to develop a  theory to explain it and make it believable and understandable to other  scientists and engineers.”

Despite the discovery, the commercialization of such a  solar-thermal reactor is likely years away. “With the price of natural gas so  low, there is no incentive to burn clean energy,” said Weimer, also the  executive director of the Colorado Center for Biorefining and Biofuels, or C2B2.  “There would have to be a substantial monetary penalty for putting carbon into  the atmosphere, or the price of fossil fuels would have to go way up.”
Source: University of Colorado at Boulder

Read more: http://www.nanowerk.com/news2/green/newsid=31656.php#ixzz2bET11D4M

Physicists at CU (Boulder, CO) create ‘recipe book’ for building new materials


(Nanowerk News) By showing that tiny particles injected  into a liquid crystal medium adhere to existing mathematical theorems,  physicists at the University of Colorado Boulder have opened the door for the  creation of a host of new materials with properties that do not exist in nature.
The findings show that researchers can create a “recipe book” to  build new materials of sorts using topology, a major mathematical field that  describes the properties that do not change when an object is stretched, bent or  otherwise “continuously deformed.” Published online Dec. 23 in the journal Nature (“Topological colloids”, the study also is the  first to experimentally show that some of the most important topological  theorems hold up in the real material world, said CU-Boulder physics department  Assistant Professor Ivan Smalyukh, a study senior author.
id28229
This  image shows polarized light interacting with a particle injected into a liquid  crystal medium. (Image: Bohdan Senyuk and Ivan Smalyukh, Colorado University)
The research could lead to upgrades in liquid crystal displays,  like those used in laptops and television screens, to allow them to interact  with light in new and different ways. One possibility is to create liquid  crystal displays that are even more energy efficient, Smalyukh said, extending  the battery life for the devices they’re attached to.
The research was funded in part by Smalyukh’s Presidential Early  Career Award for Scientists and Engineers, which he received from President  Barack Obama in 2010. And the research supports the goals laid out by the White  House’s Materials Genome Initiative, Smalyukh said, which seeks to deploy “new  advanced materials at least twice as fast as possible today, at a fraction of  the cost.”
Smalyukh, postdoctoral researcher Bohdan Senyuk, and doctoral  student Qingkun Liu set up the experiment by creating colloids — solutions in  which tiny particles are dispersed, but not dissolved, throughout a host medium.  Colloids are common in everyday life and include substances such as milk, jelly,  paint, smoke, fog and shaving cream.
For this study, the physicists created a colloid by injecting  tiny particles into a liquid crystal — a substance that behaves somewhat like a  liquid and somewhat like a solid. The researchers injected differently shaped  particles that represent fundamental building-block shapes in topology. That  means each of the particles is distinct from the others and one cannot be turned  into the other without cutting or gluing. Objects that look differently can  still be considered the same in topology if one can be turned into the other by  stretching or bending – types of “continuous deformations.”
In the field of topology, for example, an object shaped like a  donut and an object shaped like a coffee cup are treated the same. That’s  because a donut shape can be “continuously deformed” into a coffee cup by  indenting one side of the donut. But a donut-shaped object cannot be turned into  a sphere or a cylinder because the hole in the donut would have to be eliminated  by “gluing” the sides of the donut back together or by “cutting” the side of the  donut.
Once injected into a liquid crystal, the particles behaved as  predicted by topology. “Our study shows that interaction between particles and  molecular alignment in liquid crystals follows the predictions of topological  theorems, making it possible to use these theorems in designing new composite  materials with unique properties that cannot be encountered in nature or  synthesized by chemists,” Smalyukh said. “These findings lay the groundwork for  new applications in experimental studies of low-dimensional topology, with  important potential ramifications for many branches of science and technology.”
Source: University of Colorado  Boulder

Read more: http://www.nanowerk.com/news2/newsid=28237.php#ixzz2GNhHiAq0 Follow us: @nanowerk on Twitter | nanowerk on Facebook