Tag Archives: antimicrobial ties

Butterflies inspire anti-counterfeiting measures

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The Morpho butterfly is a singularly beautiful blue impossible for artists to reproduce with pigments as the colour is due to nanostructures which cause the wing’s unique optical properties. (Image copied from Wikipedia essay on Morpho butterflies.)

Photograph of a Blue Morpho butterfly (Morpho menelaus) by Gregory Phillips.

The butterfly has excited a lot of interest in the nanotechnology field and this morning (Jan. 17, 2011) research scientists (Clint Landrock and Bozena Kaminska) based at Simon Fraser University (Vancouver, Canada) announced that in an effort to eliminate currency fraud they have found a way to duplicate the butterfly’s optical properties on paper currency. It all starts with holes (from the Jan. 17, 2011 news release),

Imagine a hole so small that air can’t go through it, or a hole so small it can trap a single wavelength of light. Nanotech Security Corp., with the help of Simon Fraser University researchers, is using this type of nano-technology – 1,500 times thinner than a human hair and first of its kind in the world – to create unique anti-counterfeiting security features.

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How this works is microscopic gratings composed of nanostructures interact with light to produce the shimmering iridescence seen on the Costa Rican morpho butterfly. The nanostructures act to reflect and refract light waves to produce the morpho’s signature blue wings and absorb other unwanted light.

The highly advanced wing structures are the result of many millennia of evolution, and only recently have Nanotech’s scientists discovered how to reproduce these structures reliably. While others have talked about the possibility of re-creating it, Nanotech has made this a reality.

The U.S. Treasury, which produces up to 11 billion banknotes annually, is a potential customer for Nanotech’s product. The new U.S. $100 bill, designed with state-of-the art security features, was supposed to be introduced in February 2011 but it’s been delayed due to some manufacturing issues.

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According to Blakeway [Doug Blakeway, SFU Venture Connection’s entrepreneur in residence and also CEO and chairman of Nanotech Security Corp.], Nanotech’s product – which has attracted the attention of treasuries internationally – is superior to holograms and can’t be duplicated.

“Nobody has ever done this,” he said. “We have succeeded while everybody is still trying to duplicate or imitate a butterfly’s wing because it absorbs light and gives off the color. There’s no color pigment – there’s nothing like a dye or anything else. It’s a hole that traps light and releases color.

“You can’t copy or scan it in, you can’t inkjet it on paper, you can’t do any of these things. It’s extremely sophisticated and expensive to make the shims and dyes to produce, but very inexpensive to produce it at the end. Anywhere you can think of where a hologram is being used today, our technology can replace it. It’s more secure than a hologram. You can’t lift it off – we can put it onto metal, plastic, or paper.”

There is a video clip of a Discovery Planet item about the scientists’ presentation at the recent Las Vegas Consumer Electronics Show. (Note: The clip is about 11 minutes long and the ‘Morpho’ money item is partway through.)

I’m a little puzzled about whether or not this is really the first time (as Nanotech Security Corp. claims) someone else has been able to reproduce the butterfly’s optical properties since there is a company in Japan, Teijin, which produces ‘Morphotex’, a textile that has the same properties as the butterfly. This was mentioned in my July 19, 2010 posting which also features an image of Donna Sgro’s dress made from the textile.

Nano ties to protect against spreading the H1N1 virus; more about China and science

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Ties can carry viruses and germs just as easily as any other textile product so it makes sense that health and medical personnel would want to eliminate one more possible source of infection. The ‘nano’ tie (aka Safety Tie), which promises that you won’t inadvertently spread the H1N1 virus or other nasties,  is distributed by a company called SafeSmart.  From the company’s press release on Nanowerk,

Well before the swine flu outbreak, Florida-based SafeSmart developed a line of antimicrobial ties that has been widely accepted in healthcare, food service and other industries. SafetyTies, made of 100 percent nano-treated silk, have a built-in barrier that keeps dirt, liquids and bacteria out. In independent studies performed at BCS Laboratories of Gainesville, Florida, laboratory testing indicated that SafetyTies are 99.95 percent resistant to H1N1 influenza A.

I did try to find out about the “built-in barrier” but no details were offered in the press release or on the company’s website. Given that the tie is described as “antimicrobial,” I suspect they are binding silver nanoparticles to the silk and don’t want to make that information public.

The reluctance is understandable because of the concerns raised about silver nanoparticles, which are toxic, being washed off and ending up in the water supply. I recently noted a news item about Swiss researchers who published a study on washing silver nanoparticles off items of clothing and didn’t have time to include anything much more than links (the link to the study is no longer useful as the study is now behind a paywall). Michael Berger at Nanowerk has written in more depth about the research here. From Berger’s article,

“We found that the total released varied considerably from less than 1 to 45 percent of the total nanosilver in the fabric and that most came out during the first wash,” Bernd Nowack, head of the Environmental Risk Assessment and Management Group at the Empa-Swiss Federal Laboratories for Materials Testing and Research, tells Nanowerk. “These results have important implications for the risk assessment of silver textiles and also for environmental fate studies of nanosilver, because they show that under certain conditions relevant to washing, primarily coarse silver-containing particles are released.”

I gather this research means that manufacturers can refine their products by using finer grained silver nanoparticles to minimize the number released through washing. All of which leads me to some other questions:

  • Should we insist that no silver nanoparticles be washed off?
  • Before considering that question, I’d like to find out if we had silver nanoparticles floating around in the water prior to the manufacture of textiles made by incorporating them into the fiber.
  • Did we ingest silver nanoparticles before we had antimicrobial fabrics?
  • Does the silver come off when you sweat and where does it go then? Could your sweat represent a bigger problem than the water supply?

There is at least one other line of query that can be taken as well. Is it a good idea to limit or eliminate our exposure to bacteria and germs? There are studies which suggest that our immune systems don’t work unless they’re stimulated by the very exposure we work so vigilantly to eliminate. I’m not suggesting that we expose people to dangerous diseases so they can build up their immune systems but this mania to eliminate all germs and bacteria from our personal environments seems ill-advised to me.

I found a news item about another report on China and its research output. From the news item on Nanowerk,

“If China’s research growth remains this rapid and substantial, European and North American institutions will want to be part of it,” said Jonathan Adams, director of research evaluation at Thomson Reuters. “China no longer depends on links to traditional G8 partners to help its knowledge development. When Europe and the USA visit China they can only do so as equal partners.”

I have requested a copy of the Thomson Reuters study, Global Research Report: China, mentioned. You can request your own copy from here.