Tag Archives: zinc

The new knitting: electronics and batteries

Researchers from China have developed a new type of yarn for flexible electronics. A March 28, 2018 news item on Nanowerk announces the work, (Note: A link has been removed),

When someone thinks about knitting, they usually don’t conjure up an image of sweaters and scarves made of yarn that can power watches and lights. But that’s just what one group is reporting in ACS Nano (“Waterproof and Tailorable Elastic Rechargeable Yarn Zinc Ion Batteries by a Cross-Linked Polyacrylamide Electrolyte”). They have developed a rechargeable yarn battery that is waterproof and flexible. It also can be cut into pieces and still work.

A March 28, 2018 2018 American Chemical Society (ACS) news release (also on EurekAlert), which originated the news item, expands on the theme (Note: Links have been removed),

Most people are familiar with smartwatches, but for wearable electronics to progress, scientists will need to overcome the challenge of creating a device that is deformable, durable, versatile and wearable while still holding and maintaining a charge. One dimensional fiber or yarn has shown promise, since it is tiny, flexible and lightweight. Previous studies have had some success combining one-dimensional fibers with flexible Zn-MnO2 batteries, but many of these lose charge capacity and are not rechargeable. So, Chunyi Zhi and colleagues wanted to develop a rechargeable yarn zinc-ion battery that would maintain its charge capacity, while being waterproof and flexible.

The group twisted carbon nanotube fibers into a yarn, then coated one piece of yarn with zinc to form an anode, and another with magnesium oxide to form a cathode. These two pieces were then twisted like a double helix and coated with a polyacrylamide electrolyte and encased in silicone. Upon testing, the yarn zinc-ion battery was stable, had a high charge capacity and was rechargeable and waterproof. In addition, the material could be knitted and stretched. It also could be cut into several pieces, each of which could power a watch. In a proof-of-concept demonstration, eight pieces of the cut yarn battery were woven into a long piece that could power a belt containing 100 light emitting diodes (known as LEDs) and an electroluminescent panel.

The authors acknowledge funding from the National Natural Science Foundation of China and the Research Grants Council of Hong Kong Joint Research Scheme, City University of Hong Kong and the Sichuan Provincial Department of Science & Technology.

Here’s an image the researchers have used to illustrate their work,


Courtesy: American Chemical Society

Here’s a link to and a citation for the paper,

Waterproof and Tailorable Elastic Rechargeable Yarn Zinc Ion Batteries by a Cross-Linked Polyacrylamide Electrolyte by Hongfei Li, Zhuoxin Liu, Guojin Liang, Yang Huang, Yan Huang, Minshen Zhu, Zengxia Pe, Qi Xue, Zijie Tang, Yukun Wang, Baohua Li, and Chunyi Zhi. ACS Nano, Article ASAP DOI: 10.1021/acsnano.7b09003 Publication Date (Web): March 28, 2018

Copyright © 2018 American Chemical Society

This paper is behind a paywall.

Refining metals more sustainably

We don’t just extract and refine metals from the earth, increasingly, we extract and refine them from consumer goods. Researchers from McGill University (Montréal, Québec, Canada) have devised a ‘greener’ technique to do this. From a June 7, 2017 McGill University news release (received via email and also on EurekAlert),

A team of chemists in Canada has developed a way to process metals without using toxic solvents and reagents.

The system, which also consumes far less energy than conventional techniques, could greatly shrink the environmental impact of producing metals from raw materials or from post-consumer electronics.

“At a time when natural deposits of metals are on the decline, there is a great deal of interest in improving the efficiency of metal refinement and recycling, but few disruptive technologies are being put forth,” says Jean-Philip Lumb, an associate professor in McGill University’s Department of Chemistry. “That’s what makes our advance so important.”

The discovery stems from a collaboration between Lumb and Tomislav Friscic at McGill in Montreal, and Kim Baines of Western University in London, Ont. In an article published recently in Science Advances, the researchers outline an approach that uses organic molecules, instead of chlorine and hydrochloric acid, to help purify germanium, a metal used widely in electronic devices. Laboratory experiments by the researchers have shown that the same technique can be used with other metals, including zinc, copper, manganese and cobalt.

The research could mark an important milestone for the “green chemistry” movement, which seeks to replace toxic reagents used in conventional industrial manufacturing with more environmentally friendly alternatives. Most advances in this area have involved organic chemistry – the synthesis of carbon-based compounds used in pharmaceuticals and plastics, for example.

“Applications of green chemistry lag far behind in the area of metals,” Lumb says. “Yet metals are just as important for sustainability as any organic compound. For example, electronic devices require numerous metals to function.”

Taking a page from biology

There is no single ore rich in germanium, so it is generally obtained from mining operations as a minor component in a mixture with many other materials. Through a series of processes, that blend of matter can be reduced to germanium and zinc.

“Currently, in order to isolate germanium from zinc, it’s a pretty nasty process,” Baines explains. The new approach developed by the McGill and Western chemists “enables you to get germanium from zinc, without those nasty processes.”

To accomplish this, the researchers took a page from biology. Lumb’s lab for years has conducted research into the chemistry of melanin, the molecule in human tissue that gives skin and hair their color. Melanin also has the ability to bind to metals. “We asked the question: ‘Here’s this biomaterial with exquisite function, would it be possible to use it as a blueprint for new, more efficient technologies?'”

The scientists teamed up to synthesize a molecule that mimics some of the qualities of melanin. In particular, this “organic co-factor” acts as a mediator that helps to extract germanium at room temperature, without using solvents.

Next step: industrial scale

The system also taps into Friscic’s expertise in mechanochemistry, an emerging branch of chemistry that relies on mechanical force – rather than solvents and heat – to promote chemical reactions. Milling jars containing stainless-steel balls are shaken at high speeds to help purify the metal.

“This shows how collaborations naturally can lead to sustainability-oriented innovation,” Friscic says. “Combining elegant new chemistry with solvent-free mechanochemical techniques led us to a process that is cleaner by virtue of circumventing chlorine-based processing, but also eliminates the generation of toxic solvent waste”

The next step in developing the technology will be to show that it can be deployed economically on industrial scales, for a range of metals.

“There’s a tremendous amount of work that needs to be done to get from where we are now to where we need to go,” Lumb says. “But the platform works on many different kinds of metals and metal oxides, and we think that it could become a technology adopted by industry. We are looking for stakeholders with whom we can partner to move this technology forward.”

Here’s a link to and a citation for the paper,

A chlorine-free protocol for processing germanium by Martin Glavinovic, Michael Krause, Linju Yang, John A. McLeod, Lijia Liu, Kim M. Baines, Tomislav Friščić, and Jean-Philip Lumb. Science Advances 05 May 2017: Vol. 3, no. 5, e1700149 DOI: 10.1126/sciadv.1700149

This paper is open access.

ETA June 9, 2017 at 1700 hours PDT: I have to give them marks for creativity. Here’s the image being used to illustrate the work,

Caption: Strategy for reducing the environmental impact of a refining process: replace hazardous chemicals with more benign and recyclable compounds. Credit: Michael J. Krause (Western University)

Solar cells from the University of Alberta?

Trevor Robb’s Aug. 7, 2015 article for the Edmonton Sun (Alberta, Canada) features a research team dedicated to producing better solar cells and a facility (nanoFAB) at the University of Alberta,

But in an energy rich province like Alberta — known for its oil and gas sector — [JIllian] Buriak [chemistry professor at the University of Alberta, Canada Research chair of nanomaterials] is on a mission to shed some light on another form of energy Alberta is known for, solar energy.

So her team is dedicated to producing flexible, recyclable plastic solar cells that can be printed just like a newspaper.

In fact, they’ve already begun doing so.

In order to produce the sheet-like solar cells, Buriak and her team use nothing more than simple commercial laminators and a spray gun, not unlike something you would use to paint a car.

“We run them through this laminator that squeezes them down and turns them from something that’s not conducting to something that’s really conducting,” said Buriak.

“You could incorporate it into clothing, you could incorporate it into books, into window blinds, or unroll it on a tent when you’re camping,” said Buriak. “You could use it anywhere. Anything from simple funny things to cafe umbrellas that could allow you to charge electronic devices, to large scale things in developing countries; large scale solar cells that you could simply carry on your backpack, unroll at a medical clinic, and suddenly you have instant power.”

There are more details about Buriak’s work and information about nanoFAB in Robb’s article. As for technical information, the best I can find is in an Aug. 29, 2013 University of Alberta news release (also on EurekAlert),

University of Alberta researchers have found that abundant materials in the Earth’s crust can be used to make inexpensive and easily manufactured nanoparticle-based solar cells.

The discovery, several years in the making, is an important step forward in making solar power more accessible to parts of the world that are off the traditional electricity grid or face high power costs, such as the Canadian North, said researcher Jillian Buriak, a chemistry professor and senior research officer of the National Institute for Nanotechnology based on the U of A campus.
Buriak and her team have designed nanoparticles that absorb light and conduct electricity from two very common elements: phosphorus and zinc. Both materials are more plentiful than scarce materials such as cadmium and are free from manufacturing restrictions imposed on lead-based nanoparticles.

Buriak collaborated with U of A post-doctoral fellows Erik Luber of the U of A Faculty of Engineering and Hosnay Mobarok of the Faculty of Science to create the nanoparticles. The team was able to develop a synthetic method to make zinc phosphide nanoparticles, and demonstrated that the particles can be dissolved to form an ink and processed to make thin films that are responsive to light.

Buriak and her team are now experimenting with the nanoparticles, spray-coating them onto large solar cells to test their efficiency. The team has applied for a provisional patent and has secured funding to enable the next step to scale up manufacture.

I wonder if this news article by Robb is an attempt by Buriak to attract interest from potential investors?

Zimbabwe and its international nanotechnology center, ZINC

A Sept.24, 2012 news item on Nanowerk provides information about a new nanotechnology center in Zimbabwe,

With 14 percent of Zimbabwe’s population living with HIV/AIDS and tuberculosis as a co-infection, the need for new drugs and new formulations of available treatments is crucial.

To address these issues, two of the University at Buffalo’s [UB] leading research centers, the Institute for Lasers, Photonics and Biophotonics (ILPB), and the New York State Center of Excellence in Bioinformatics and Life Sciences have signed on to launch the Zimbabwe International Nanotechnology Center (ZINC) — a national nanotechnology research program — with the University of Zimbabwe (UZ) and the Chinhoyi University of Technology (CUT).

This collaborative program will initially focus on research in nanomedicine and biosensors at UZ and energy at CUT. ZINC has grown out of the NIH [US National Institute of Health] Fogarty International Center, AIDS International Training and Research Program (AITRP) that was awarded to UB and UZ in 2008 to conduct HIV research training and build research capacity in Zimbabwe and neighboring countries in southern Africa.

I decided to find out more about Zimbabwe and found a map and details in a Wikipedia essay,

Location of Zimbabwe within the African Union (accessed Sept. 24, 2012 from the Wikipedia essay on Zimbabwe)

Zimbabwe (… officially the Republic of Zimbabwe) is a landlocked country located in Southern Africa, between the Zambezi and Limpopo rivers. It is bordered by South Africa to the south, Botswana to the southwest, Zambia and a tip of Namibia to the northwest (making this area a quadripoint) and Mozambique to the east. The capital is Harare. Zimbabwe achieved recognised independence from Britain in April 1980, following a 14-year period as an unrecognised state under the predominantly white minority government of Rhodesia, which unilaterally declared independence in 1965. Rhodesia briefly reconstituted itself as black-majority ruled Zimbabwe Rhodesia in 1979, but this order failed to gain international acceptance.

Zimbabwe has three official languages: English, Shona and Ndebele.

Getting back to Zimbabwe, Alan on the Science Business website posted on Sept. 24, 2012 about ZINC and the partnership (excerpted from the posting),

University at Buffalo in New York and two universities in the southern African nation of Zimbabwe will collaborate on a new nanotechnology research program in pharmacology. University of Zimbabwe in Harare and the Chinhoyi University of Technology in Mashonaland West, working with Buffalo’s Institute for Lasers, Photonics, and Biophotonics, along with New York State Center of Excellence in Bioinformatics and Life Sciences also on the Buffalo campus, will establish the Zimbabwe International Nanotechnology Center (ZINC).

ZINC aims to develop an international research and training capability in nanotechnology that advances the field as contributor to Zimbabwe’s economic growth. The collaboration is expected to focus on research in nanomedicine and biosensors for health care at University of Zimbabwe, while the Chinhoyi University of Technology partnership will conduct research related to energy.

The University of Buffalo Sept. 24, 2012 news release provides more details,

The UB ILPB and TPRC [Translational Pharmacy Research Core] collaboration recognized that the fields of pharmacology and therapeutics have increasingly developed links with emerging areas within the field of nanosciences in an attempt to develop tissue/organ targeted strategies that will lead to disease treatment and eradication. Research teams will focus on emerging technologies, initially focused in nanobiotechnology and nanomedicine for health care.

“Developing nanoformulations for HIV and tuberculosis diagnostics and therapeutics, as well as new tuberculosis drug development, are just a few of the innovative strategies to address these co-infections that this research collaboration can provide,” said Morse [Gene D. Morse, PharmD, Professor of Pharmacy Practice, associate director of the New York State Center of Excellence in Bioinformatics and Life Sciences and director of the Translational Pharmacy Research Core {TPRC}].

“In addition, the development of new nanotechnology-related products will jumpstart the economy and foster new economic initiatives in Zimbabwe that will yield additional private-public partnerships.”

Morse says that the current plans for a “Center of Excellence” in clinical and translational pharmacology in Harare at UZ will create a central hub in Africa, not just for Zimbabwe but for other countries to gain new training and capacity building in many exciting aspects of nanotechnology as well.

Good luck to ZINC and its partners!

Could nanoparticles in your mouthwash affect for your cells?

The first news item I’m going to highlight was posted on Nanowerk, March 8, 2012 and is focused on the use of silver nanoparticles in mouthwashes and dentures to prevent yeast infections,

Yeasts which cause hard-to-treat mouth infections are killed using silver nanoparticles in the laboratory, scientists have found. These yeast infections, caused by Candida albicans and Candida glabrata target the young, old and immuno-compromised. Professor Mariana Henriques, University of Minho [Portugal], and her colleagues hope to test silver nanoparticles in mouthwash and dentures as a potential preventative measure against these infections.

Professor Henriques and her team, who published their research in the Society for Applied Microbiology’s journal Letters in Applied Microbiology(“Silver nanoparticles: influence of stabilizing agent and diameter on antifungal activity against Candida albicans and Candida glabrata biofilms”), looked at the use of different sizes of silver nanoparticles to determine their anti-fungal properties …

The scientists used artificial biofilms in conditions which mimic those of saliva as closely as possible. They then added different sizes and concentrations of silver nanoparticles and found that different sizes of nanoparticles were equally effective at killing the yeasts. Due to the diversity of the sizes of nanoparticles demonstrating anti-fungal properties the researchers hope this will enable the nanoparticles to be used in many different applications.

Some researchers have expressed concerns around the safety of nanoparticle use but the authors stress this research is at an early stage and extensive safety trials will be carried out before any product reaches the market. [emphasis mine]

Following on the notion of safety and gargling silver nanoparticles, coincidentally, there was another news item also dated March 8, 2012 on Nanowerk, this one about the impact that nanoparticles may have on nutrient uptake,

Nanoparticles are everywhere. From cosmetics and clothes, to soda and snacks. But as versatile as they are, nanoparticles also have a downside, say researchers at Binghamton University and Cornell University in a recent paper published in the journal Nature Nanotechnology (“Oral exposure to polystyrene nanoparticles affects iron absorption”). These tiny particles, even in low doses, could have a big impact on our long-term health.

According to lead author of the article, Gretchen Mahler, assistant professor of bioengineering at Binghamton University, much of the existing research on the safety of nanoparticles has been on the direct health effects. But what Mahler, Michael L. Shuler of Cornell University and a team of researchers really wanted to know was what happens when someone gets constant exposure in small doses – the kind you’d get if you were taken a drug or supplement that included nanoparticles in some form. [e.g. silver nanoparticles in your mouthwash or on your dentures]

“We thought that the best way to measure the more subtle effects of this kind of intake was to monitor the reaction of intestinal cells,” said Mahler. “And we did this in two ways: in vitro, through human intestinal-lining cells that we had cultured in the lab; and in vivo, through the intestinal linings of live chickens. Both sets of results pointed to the same thing – that exposure to nanoparticles influences the absorption of nutrients into the bloodstream.”

As for why the researchers focused on iron and tested polystyrene nanoparticles (from the news item),

The uptake of iron, an essential nutrient, was of particular interest due to the way it is absorbed and processed through the intestines. The way Mahler and the team tested this was to use polystyrene nanoparticles because of its easily traceable fluorescent properties.

“What we found was that for brief exposures, iron absorption dropped by about 50 percent,” said Mahler. “But when we extended that period of time, absorption actually increased by about 200 percent. It was very clear – nanoparticles definitely affects iron uptake and transport.”

While acute oral exposure caused disruptions to intestinal iron transport, chronic exposure caused a remodeling of the intestinal villi – the tiny, finger-like projections that are vital to the intestine’s ability to absorb nutrients – making them larger and broader, thus allowing iron to enter the bloodstream much faster.

As to whether these changes are good or bad the researchers don’t speculate. They do have plans for more testing,

zinc, and
fat-soluble vitamins A, D, E and K

They don’t mention any changes in the types of nanoparticles they might be testing in future.

In any event, our bodies have changed a lot over the centuries, you just have to visit a pyramid in Egypt or a museum that holds medieval armour to observe that humans were once much shorter than we are today.

Enriching food with nanoparticles?

There’s a team of Swiss researchers addressing the problem of anemia (iron deficiency) and zinc deficiency by adding iron and/or zinc nanoparticles to food. According to the article by Eric Bland on the Discovery News website,

“Iron and zinc deficiencies are common around the world,” said Michael Zimmermann, a scientist at ETH Zurich and a co-author of a recent Nature Nanotechnology article. “Yet many compounds used in food fortification are either absorbed poorly or, when they have high absorption, change the color, taste and smell of food.”

Anemia, or a lack of iron, affects more than 2 billion people worldwide and is arguably the most widespread micronutrient deficiency. Without enough iron the the body can become lethargic and cognitively impaired. For some pregnant women, the lack of iron can kill them during childbirth. Some economists have even speculated that a nation’s gross domestic product is depressed because of anemic and lethargic workers, said Zimmermann.

Lack of zinc impairs a person’s normal growth and can lead to diarrhea, pneumonia, anorexia and other conditions.

Standard ways of fortifying food with zinc and/or iron present various challenges including this one as noted by Zimmermann only a limited amount of iron can be added as it affects the food’s taste, smell, and/or appearance (this and other challenges are detailed in Bland’s article). So scientists continue to work on better ways to fortify food so that more people on the planet can benefit. The Swiss team’s approach,

The new research solves this conundrum. To create the nanoparticles the Swiss scientists dissolved iron in water, then sprayed the solution over very hot fire. The intense heat quickly evaporates the water, leaving tiny iron or zinc crystals, each one about 10 nanometers across. Those nanocrystals then clump together.

The large clumps do not change the taste, color or smell of food. When the clumps drop into the stomach acid, however, they break apart into tiny particles, which are easily absorbed by the body.

These zinc and/or iron nanoparticles, which do not affect the food’s taste, smell, or appearance, have been tested on rats. (I wonder how they figured out that taste isn’t affected since there haven’t been any human clinical trials.) More research needs to be done before humans get a chance to try these nanotechnology-enabled foods but this does seem promising.

By the way, the rats were fed chocolate milk and banana smoothies.