August 20, 2008 at 5:44 pm #28916
note: China at one time(really the world)focused on finding new things they could produce out of Silk and hemp. Then came along petrolium, and well the rest is history.
Silk-Based Optical Lenses Green Enough to Eat
Eric Bland, Discovery News
Aug. 20, 2008 — Boiling a sleeping insect alive can make for a new generation of “green” optical devices, according to scientists at Tufts University.
The new silk-based lenses are a nontoxic alternative to glass and plastics and could be equipped with tiny sensors to create a new generation of biodegradable medical devices.
“Anything you can do with traditional plastics you could do with silk,” said David Kaplan, one of the co-authors of the study that appeared recently in the journal Biomacromolecules.
“It is as green as you can get — all water processing, natural proteins, etc.”
To make their devices Kaplan and his colleagues boiled the pupae of the Bombyx mori silkworm alive to kill them (standard practice for silk processing) and loosen up the raw silk. They then removed the protein glue that holds the single, unbroken, and up to 3,000-foot-long single strand of silk.
The scientists then took the watery solution of silk and poured it onto a mold and let it air dry, doused it with water, and dried it again. From those films they produced optical lenses between 10 and 100 micrometers that were of roughly equal quality to plastic and glass lenses.
“It’s not trivial that you can make very clear lenses and films with silk,” said Kaplan. “And second, when we expose them to lasers they behave in an interesting fashion and let us diffract white light with lots of control.”
The entire process takes place at normal room temperatures and without the toxic chemical solvents most industrial processes use to create many glass or plastic-based optical devices today.
The researchers say that their silk-based products could be a clean, green replacement for nearly anything made of plastic or glass that would eventually degrade naturally over time when exposed to light.
Still, just because a product can be made of silk doesn’t mean it will be. The materials come at a high cost.
Feeding silk worms white mulberry leaves, their favorite food, is more expensive than pumping oil or melting sand, basic ingredients for plastic and glass (at least for now). Silk-based products would likely be limited to biomedical devices that are already relatively expensive or where toxicity and the ability to biodegrade are necessary.
The researchers proposed several uses for their silk-based material besides lenses. A silk-based material could be put in put into perishable food that would indicate if it has been contaminated. The material could also be implanted into the body and offer a person a year’s-worth of insulin readings before dissolving harmlessly.
Kaplan notes that silk is already a Food and Drug Administration-approved biomedical material, which should speed up, or possibly eliminate, the lengthy FDA approval process.
Jayant Kumar, a material scientist at the University of Massachusetts, Lowell who was not involved in the Tufts research, thinks that the new silk-based products will still have to go through FDA approval.
“It has tremendous potential for biomedical applications beyond just optics,” said Kumar. “This technique could be a great way to grow cells and tissues.”
According to Kumar, the cultivated tissue could then be implanted into the body and the silk would eventually break down naturally.
“There are already other fibers that can do this,” said Kumar. “But they are not easy to produce and are certainly not green at all.”August 20, 2008 at 10:54 pm #28917
Thanks for the article, Dog–I’m all for it.
Slowly but surely, I’ve been developing a personal silent war
against plastics (I guess not silent now).
Even years ago when I was a teenager and still
drinking soft drinks, I knew something wasn’t quite right when they
switched from glass bottles to plastic bottles. The beverages
just didn’t taste right–little did I know . . .
Fast forward to a couple of years ago, when my beverage of choice
became water–I stopped drinking tap water and drinking bottled
water because of the chlorine (causes heart disease) in tap water and other
chemicals added to tap water–tasted gross anyway.
All the plastic water bottles I felt were a waste–made an effort to
recycle them. However, it wasn’t so useful for going to school.
I’d bring in a plastic water bottle and loose it by the end of the day–so
I thought I’d be environmentally conscious and I bought a “Nalgene
sports water bottle”. I’d fill it up before going in each day with
filtered water I bought at the store.
Then toward the end of last year, I find out about the fact that
polycarbonate (the plastic used in the Nalgene sports water bottles)
leaches BISPHENOL-A into the water from the plastic. It’s a chemical
that causes cancer, genetic damage, and all kinds of other harmful
things. I quit using the water bottle. Nalgene replaced their
water bottles with new water bottles that “supposedly” didn’t
leach this chemical into the water, but I’m not trusting that again.
So recently I tried to find some other water container to bring
water to school in. I went to Meijer to find one. Impossible to
find any water bottle or container NOT made with plastic. Decide
on an all out war on plastic, and decide to try to replace my
plastic water jugs with glass. Also, NO glass jugs at Meijer, just
plastic–a few that sort of look like glass, but are glass-fakes–they
are basically polycarbonate (plastic) in disguise.
I go to Bed, Bath, and Beyond–figuring surely they’d have something.
NOPE. Plastics. Clear plastic polycarbonate, dark plastics, plastics,
plastics, plastics! I decide that the water bottle is the most
important thing, and decide on getting a “camping canteen”, as that
should be made out of steel. I go to Dick’s Sporting Goods, Dunham’s
Outfitters, etc., and all you see are those damn plastic sports
water bottles. You *can’t* buy a non-plastic version.
I do some searching online. I stumbled upon a website
They have some products on there, and some facts about plastic
that are downright scary.
For starters, aside from the problems with polycarbonate plastic
and Bisphenol-A, many other plastics also leach deadly industrial
chemicals into the water.
Standard Pete-1 plastic used in the “disposable” water bottles
and in a lot of other containers, leach Antimony Trioxide.
Polystyrene (i.e. Styrofoam) leaches Styrene.
Go and look and see what PVC leaches!
It’s thought that some of the problems people have with
anxiety disorders is due to the large volume of these
industrial chemicals that have entered their bodies–and it
is a poisoned response . . .
At any rate, I’m slowly (because it’s hard), getting rid of
anything I have that holds food or beverage in plastic.
Too impossible to eradicate all plastic, but at least for
food and beverage I’m not going to use any plastic unless I
have to. I’m going to limit my use of the “disposable” plastic
water bottles to finishing what I have and/or limited use
on extended trips where I can’t get access to filtered water.
The website offers a number of “plastic-alternatives”–mostly
stainless steel (which is better than aluminum; you mostly
want to avoid aluminum for food containers or cooking pots
because there is a link between aluminum content in the body
and Alzheimer’s disease; there is a excess buildup of aluminum
in the brain in these patients . . .)
You can’t buy the glass water jugs online from them–you can
only pick them up in their store. I did find an online
supplier of glass jugs though . . .
I don’t think there is a “perfect” solution, but I have
decided that I’m done with my steady diet of industrial
toxic chemicals from plastic food containers.
StevenAugust 21, 2008 at 4:37 pm #28919
I use my left over goji bottles as water bottles. Thanks for the link.August 21, 2008 at 5:20 pm #28921
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