Posts belonging to Category nanosponge



How To Stay Dry Underwater For Months

Imagine staying dry underwater for months. Now Northwestern University engineers have examined a wide variety of surfaces that can do just that — and, better yet, they know why. The research team is the first to identify the ideal “roughness” needed in the texture of a surface to keep it dry for a long period of time when submerged in water. The valleys in the surface roughness typically need to be less than one micron in width, the researchers found. That’s really small — less than one millionth of a meter — but these nanoscopic valleys have macroscopic impact. Understanding how the surfaces deflect water so well means the valuable feature could be reproduced in other materials on a mass scale, potentially saving billions of dollars in a variety of industries, from antifouling surfaces for shipping to pipe coatings resulting in lower drag. That’s science and engineering, not serendipity, at work for the benefit of the economy.

Dry underwater

The trick is to use rough surfaces of the right chemistry and size to promote vapor formation, which we can use to our advantage,” said Neelesh A. Patankar, a professor of mechanical engineering in the McCormick School of Engineering and Applied Science, who led the research. “When the valleys are less than one micron wide, pockets of water vapor or gas accumulate in them by underwater evaporation or effervescence, just like a drop of water evaporates without having to boil it. These gas pockets deflect water, keeping the surface dry,” he said.

In a study published today (Aug. 18) by the journal Scientific Reports, Patankar and his co-authors explain and demonstrate the nanoscale mechanics behind the phenomenon of staying dry underwater.

-Source: http://www.northwestern.edu/

How To Boost Electric Vehicle Batteries

Researchers from the Professor Mihri Ozkan lab at the University of California, Riverside’s Bourns College of Engineering have developed a novel paper-like material for lithium-ion batteries. It has the potential to boost by several times the specific energy, or amount of energy that can be delivered per unit weight of the battery.
This paper-like material is composed of sponge-like silicon nanofibers more than 100 times thinner than human hair. It could be used in batteries for electric vehicles and personal electronics.

electric carThe problem with silicon is that is suffers from significant volume expansion, which can quickly degrade the battery. The silicon nanofiber structure created in the Ozkan’s labs circumvents this issue and allows the battery to be cycled hundreds of times without significant degradation. This technology also solves a problem that has plagued free-standing, or binderless, electrodes for years: scalability. Free-standing materials grown using chemical vapor deposition, such as carbon nanotubes or silicon nanowires, can only be produced in very small quantities (micrograms). However, the team was able to produce several grams of silicon nanofibers at a time even at the lab scale.

The nanofibers were produced using a technique known as electrospinning, whereby 20,000 to 40,000 volts are applied between a rotating drum and a nozzle, which emits a solution composed mainly of tetraethyl orthosilicate (TEOS), a chemical compound frequently used in the semiconductor industry. The nanofibers are then exposed to magnesium vapor to produce the sponge-like silicon fiber structure.

The findings were just published in the journal Nature Scientific Reports.
Source: http://www.mse.ucr.edu/

Nano Sponges Cut Greenhouse Gases

In the fight against global warming, carbon capture – chemically trapping carbon dioxide before it releases into the atmosphere – is gaining momentum, but standard methods are plagued by toxicity, corrosiveness and inefficiency. Using a bag of chemistry tricks, Cornell materials scientists have invented low-toxicity, highly effective carbon-trapping “sponges” that could lead to increased use of the technology. A research team led by Emmanuel Giannelis, Professor of Engineering, has invented a powder that performs as well or better than industry benchmarks for carbon capture.
The researchers have been working on a better, safer carbon-capture method . Their latest consists of a silica scaffold, the sorbent support, with nanoscale pores for maximum surface area. They dip the scaffold into liquid amine, which soaks into the support like a sponge and partially hardens. The finished product is a stable, dry white powder that captures carbon dioxide even in the presence of moisture.

nanosponges
A scanning electron microscopy image of a pristine silica support, before the amine is added
We have made great strides in sustainability, particularly in the energy supply areas of alternative energy sources, and the demand side areas of energy conservation and building design standards,” KyuJung Whang, Cornell’s vice president for facilities services said.

A paper with their results, co-authored by postdoctoral associates Genggeng Qi and Liling Fu, appeared in Nature Communications.
Source: http://news.cornell.edu/

Stronger Microbes To Clean Up Nuclear Waste

A microbe developed to clean up nuclear waste and patented by a Michigan State University (MSU)researcher has just been improved. In earlier research, Gemma Reguera, MSU microbiologist, identified that Geobacter bacteria’s tiny conductive hair-like appendages, or pili, did the yeoman’s share of remediation. By increasing the strength of the pili nanowires, she improved their ability to clean up uranium and other toxic wastes. In new research, published in the current issue of Applied and Environmental Microbiology, Reguera has added an additional layer of armor to her enhanced microbes. The microbes also use the pili to stick to each other and grow a film on just about any surface, similar to the bacterial film that forms on teeth. The Geobacter biofilm, encased by a network of nanowires and slime, gives the bacteria a shield and increases their ability to neutralize even more uranium. The improvement also allows the bacteria to survive longer even when exposed to higher concentrations of the radioactive material. Geobacter immobilizing uranium can be described as nature’s version of electroplating. The beefed-up microbes engulf the uranium and turn it into a mineral, preventing the toxic material from leaching into groundwater.
nucelar waste
The results surpassed our most optimistic predictions,” Reguera said. “Even thin biofilms immobilized uranium like sponges. They reduced it to a mineral, all while not suffering any damage to themselves, for prolonged periods of time.
Source: http://msutoday.msu.edu/

Less Than One Percent of Nanotubes Pass The Pulmonary Barrier

Having perfected an isotope labeling method allowing extremely sensitive detection
of carbon nanotubes in living organisms, CEA and CNRS  researchers have looked at what happens to nanotubes after one year inside
an animal.
Studies in mice revealed that a very small  percentage (0.75%of  the  initial  quantity of  nanotubes  inhaled  crossed  the pulmonary epithelial barrier  and translocated to the  liverspleen,  and  bone  marrow.

Although  these  results  cannot  be  extrapolated  to  humans,  this  work
highlights  the importance  of  developing  ultrasensitive  methods  for 
assessing
  the  behavior of nanoparticles in animals.

Nanotoxicology

Carbon  nanotubes  are  highly  specific  nanoparticles  with  outstanding mechanical and electronic properties that make them suitable for use in a wide
range of applications, from structural materials to certain electronic components.
Their many present and future uses explain why research teams around the world
are now focusing on their impact on human health and the environment.

The findings  have been published in the journal ACSNano.
CEA and CNRS are located in Paris, France.

Source: http://www2.cnrs.fr/

Nanotechnology: Food And Drug Administration Rules

Today, 3 final guidances and one draft guidance were issued by the U.S. Food and Drug Administration (FDA) providing greater regulatory clarity for industry on the use of nanotechnology in FDA-regulated products.
One final guidance addresses the agency’s overall approach for all products that it regulates, while the two additional final guidances and the new draft guidance provide specific guidance for the areas of foods, cosmetics and food for animals, respectively.

Nanotechnology is an emerging technology that allows scientists to create, explore and manipulate materials on a scale measured in nanometers—particles so small that they cannot be seen with a regular microscope. The technology has a broad range of potential applications, such as improving the packaging of food and altering the look and feel of cosmetics.

SILVER NANOPARTICLES

Our goal remains to ensure transparent and predictable regulatory pathways, grounded in the best available science, in support of the responsible development of nanotechnology products,” said FDA Commissioner Margaret A. Hamburg, M.D. “We are taking a prudent scientific approach to assess each product on its own merits and are not making broad, general assumptions about the safety of nanotechnology products.”

The 3 final guidance documents reflect the FDA’s current thinking on these issues after taking into account public comment received on the corresponding draft guidance documents previously issued (draft agency guidance in 2011; and draft cosmetics and foods guidances in 2012).

The FDA does not make a categorical judgment that nanotechnology is inherently safe or harmful, and will continue to consider the specific characteristics of individual products.
All 4 guidance documents encourage manufacturers to consult with the agency before taking their products to market. Consultations with the FDA, early in the product development process help to facilitate a mutual understanding about specific scientific and regulatory issues relevant to the nanotechnology product, and help address questions related to safety, effectiveness, public health impact and/or regulatory status of the product.
Source: http://www.fda.gov/

Nanosponge Vaccine Fights MRSA Toxins

Nanosponges that soak up a dangerous pore-forming toxin produced by MRSA (methicillin-resistant Staphylococcus aureus) could serve as a safe and effective vaccine against this toxin. This “nanosponge vaccine” enabled the immune systems of mice to block the adverse effects of the alpha-haemolysin toxin from MRSA—both within the bloodstream and on the skin. Nanoengineers from the University of California, San Diego described the safety and efficacy of this nanosponge vaccine in the journal Nature Nanotechnology.nanosponge-vaccine
The glowing yellow specks in the image show uptake of the nanosponge vaccine by a mouse dendritic cell, which is an immune-system cell. The nanovaccine’s detained alpha-haemolysin toxins were labeled with a dye which glows yellow and can be seen glowing after uptake by the dendritic cell. The cell membrane is stained red and the nucleus is stained blue
With our toxoid vaccine, we don’t have to worry about antibiotic resistance. We directly target the alpha-haemolysin toxin,” said Liangfang Zhang, a nanoengineering professor at UC San Diego Jacobs School of Engineering and the senior author on the paper published in Nature Technology. Targeting the alpha-haemolysin toxin directly has another perk. “These toxins create a toxic environment that serves as a defense mechanism which makes it harder for the immune system to fight Staph bacteria,” explained Zhang.

Source: http://ucsdnews.ucsd.edu/