Wooden bones

Paul Raven @ 13-08-2009

If you wanted to build artificial bones, what material would you use? I don’t know about you, but wood wouldn’t have been high up my list.

To create the bone substitute, the scientists start with a block of wood — red oak, rattan and sipo work best — and heat it until all that remains is pure carbon, which is basically charcoal.

[…]

The scientists then spray calcium over the carbon, creating calcium carbide. Additional chemical and physical steps convert the calcium carbide into carbonated hydroxyapatite, which can then be implanted and serves as the artificial bone.

The entire process takes about one week and costs about $850 for a single block. One block translates to about one bone implant.

I’ve no idea how that compares with other artificial bone manufacture techniques on price and speed, but it’s still fairly impressive on novelty value alone. [via SlashDot]


This blog post will self-destruct in thirty seconds

Paul Raven @ 09-07-2009

If you’ve been hankering for an intersection of nanomaterials and old spy movie cliches, today’s your day: a gang of researchers in Illinois reckon they’ve found a way to use nanoparticles to make messages that erase themselves after a certain amount of time.

A team at Northwestern University in Evanston, Illinois, coated gold nanoparticles with a layer of hair-like molecules called 4-(11-mercaptoundecanoxy)azobenzene or MUA. When zapped with ultraviolet light, these filaments change their shape and charge distribution, causing the nanoparticles to congregate together and change colour […]

To put this colour-changing ability to good use, the team dispersed the nanoparticles in a gel and sandwiched it between plastic sheets to produce a thin, red film. When Grzybowski and his colleagues shone UV light at the film, either through a patterned mask or using a UV pen, they found they could print a range of images or write words onto the film in just a few seconds.

The colour change is not permanent, however. In the absence of UV light, the MUA gradually reverts to its original shape, allowing the nanoparticles to disperse and the images to disappear.

Your mission, should you choose to accept it, is to work out how many times more expensive and complicated it would be to use this stuff instead of scribbling a note on some rice paper. Or whether the Etch-a-Sketch people will be tempted to build a 2.0 version.


A material world

Tom James @ 22-06-2009

layersA rather touching story of one man’s creation of a vast materials library of weird and wonderful substances, Mark Miodownik talks about the Kings College Materials Library:

There are turbine jet-engine blades grown from a single crystal and designed to function in the most inhospitable places on the planet. There’s a swatch of the world’s blackest black, 25 times blacker than conventional black paint. There’s a lead bell that refuses to ring, a piece of bone with a saw through it, and the largest blob of Silly Putty you’re ever likely to see.

The philosophy behind the project is charming as well, an attempt to bridge the gap between the two cultures of science and art:

“It’s a way into science for arts people,” Miodownik says. “And for the scientists it’s a lesson in aesthetics and the sensual nature of what they’re doing. It’s a place for people to go to who have an idea floating around the back of their head that hasn’t bubbled to the surface yet.”

[image from doug88888 on flickr][from the FT]


New resin for growing flesh

Tom James @ 09-06-2009

biodegradable_resinResearchers at the University of Twente have developed a biodegradable resin that can be used to create precise replicas of forms within the body around which new tissues can be grown:

The resin can be given different properties depending on where in the body it is to be used. Cells can be sown and cultured on these models, so that the tissues grown are, in fact, produced by the body itself. The new resin has been developed by Ferry Melchels and Prof. Dirk Grijpma of the UT’s Polymer Chemistry and Biomaterials research group. An article on this breakthrough will be appearing in the authoritative specialist journal, Biomaterials

The method used to recreate the specific forms is called stereolithography, the improvement in this system is that the resins have hitherto not been biodegradable. This means:

If, for example, a child has a heart valve disorder, a 3D digital image of the heart valve can be created using a CT scanner. The model in the stereolithograph can be copied exactly with the new resin. If the structure is made porous, the child’s own cells can be placed on it. This porosity also gives nutrients access to the cells. Ultimately, after the carrier structure has broken down, only the natural tissue remains.

Which is a rather wonderful development.

[from Physorg]


Nanoscale etchings make liquid flow uphill

Paul Raven @ 04-06-2009

OK, I can’t resist it – here’s an OMGZ SCIENCE!!1 story that is too good to pass up: nanoscale laser etchings on metallic surfaces can produce weird effects in their interaction with liquids, including the ability to make them flow against gravity.

Chunlei Guo, associate professor of optics at the University of Rochester in New York State, says: “We’re able to change the surface structure of almost any piece of metal so that we can control how liquid responds to it. We can even control the direction in which the liquid flows, or whether liquid flows at all.

That’s pretty cool in and of itself, but here’s your real sensawunda kick:

Guo and his assistant, Anatoliy Vorobyev, alter the surface of the metal using an ultra-fast burst of light from a laser. Science Daily reports: “The laser, called a femtosecond laser, produces pulses lasting only a few quadrillionths of a second—a femtosecond is to a second what a second is to about 32 million years.” It adds that this one burst unleashes as much power as the whole of North America’s electric grid delivers, but “focused onto a spot the size of a needlepoint”.

Science FTW! It’s days like this I wish I’d actually finished my undergraduate courses…


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