http://nextbigfuture...able-sugar.html
looks like bulk manufacture of graphene has really taken off in the last year.
"At 800 degrees, the underlying silicon remains active for electronics, whereas at 1,000 degrees, it loses its critical dopants," said Tour, Rice's T.T. and W.F. Chao Chair in Chemistry as well as a professor of mechanical engineering and materials science and of computer science.
Zhengzong Sun, a fourth-year graduate student in Tour's lab and primary author of the paper, found that depositing carbon-rich sources on copper and nickel substrates produced graphene in any form he desired: single-, bi- or multilayer sheets that could be highly useful in a number of applications.
Sun and his colleagues also found the process adapts easily to producing doped graphene; this allows the manipulation of the material's electronic and optical properties, which is important for making switching and logic devices.
For pristine graphene, Sun started with a thin film of poly (methyl methacrylate) (PMMA) -- perhaps best known in its commercial guise as Plexiglas -- spun onto a copper substrate that acted as a catalyst. Under heat and low pressure, flowing hydrogen and argon gas over the PMMA for 10 minutes reduced it to pure carbon and turned the film into a single layer of graphene. Changing the gas-flow rate allowed him to control the thickness of the PMMA-derived graphene.
Then it got more interesting, Sun said. He turned to other carbon sources, including a fine powder of sucrose -- aka table sugar. "We thought it would be interesting to try this stuff," Sun said. "While other labs were changing the metal catalysts, we tried changing the carbon sources."
Sun put 10 milligrams of sugar (and later fluorene) on a square-centimeter sheet of copper foil and subjected it to the same reactor conditions as the PMMA. It was quickly transformed into single-layer graphene. Sun had expected defects in the final product, given the chemical properties of both substances (a high concentration of oxygen in sucrose, five-atom rings in fluorene); but he found potential topological defects would self-heal as the graphene formed.
"As we looked deeper and deeper into the process, we found it was not only interesting, but useful," Sun said.
He tried and failed to grow graphene on silicon and silicon oxide, which raised the possibility of growing patterned graphene from a thin film of shaped copper or nickel deposited onto silicon wafers.
Doped graphene opens more possibilities for electronics use, Tour said, and Sun found it fairly simple to make. Starting with PMMA mixed with a doping reagent, melamine, he discovered that flowing the gas under atmospheric pressure produced nitrogen-doped graphene. Pristine graphene has no bandgap, but doped graphene allows control of the electrical structure, which the team proved by building field-effect transistors.
"Each day, the growth of graphene on silicon is approaching industrial-level readiness, and this work takes it an important step further," Tour said.
Which is good considering that we're also making progress in nanoelectronics manufacturing techniques
http://nextbigfuture.com/2010/11/ice-lithography-for-nanodevices.html
We report the successful application of a new approach, ice lithography (IL), to fabricate nanoscale devices. The entire IL process takes place inside a modified scanning electron microscope (SEM), where a vapor-deposited film of water ice serves as a resist for e-beam lithography, greatly simplifying and streamlining device fabrication. We show that labile nanostructures such as carbon nanotubes can be safely imaged in an SEM when coated in ice. The ice film is patterned at high e-beam intensity and serves as a mask for lift-off without the device degradation and contamination associated with e-beam imaging and polymer resist residues. We demonstrate the IL preparation of carbon nanotube field effect transistors with high-quality trans-conductance properties.
http://nextbigfuture.com/2010/11/interconnecting-gold-islands-with-dna.html
Scaffolded DNA origami has recently emerged as a versatile, programmable method to fold DNA into arbitrarily shaped nanostructures that are spatially addressable, with sub-10-nm resolution. Toward functional DNA nanotechnology, one of the key challenges is to integrate the bottom-up self-assembly of DNA origami with the top-down lithographic methods used to generate surface patterning. In this report we demonstrate that fixed length DNA origami nanotubes, modified with multiple thiol groups near both ends, can be used to connect surface patterned gold islands (tens of nanometers in diameter) fabricated by electron beam lithography (EBL). Atomic force microscopic imaging verified that the DNA origami nanotubes can be efficiently aligned between gold islands with various interisland distances and relative locations. This development represents progress toward the goal of bridging bottom-up and top-down assembly approaches.
http://nextbigfuture.com/2010/11/crystalline-two-dimensional-dna-origami.html
DNA origami gets large: A double-layer DNA-origami tile with two orthogonal domains underwent self-assembly into well-ordered 2D DNA arrays with edge dimensions of 2–3 μm (see schematic representation and AFM image). This size is likely to be large enough to connect bottom-up methods of patterning with top-down approaches.
seems like that graphene nanoelectronics chip is getting closer to manufacture every day, and with the recent breakthroughs in nanogenerators ( http://nextbigfuture...ators-grow.html ) and high ratio field effect transistors (http://nextbigfuture.com/2010/11/high-onoff-ratio-graphene.html) as well, we may see prototypes by 2013
Now, in the field of stemcell based plastic surgery, I just wrote a new article for H+ magazine, in which I described how it is likely that stemcell based "theraputic cloning" could enable a male to female sex conversion that would allow even reproductive ability as the new sex. So, I like write the article, send it off, and the very next day...
http://www.physorg.c...multaneous.html
Bioengineers from the University of California, San Diego have achieved the "Triple Crown" of stem cell culture – they created an artificial environment for stem cells that simultaneously provides the chemical, mechanical and electrical cues necessary for stem cell growth and differentiation. Building better microenvironments for nurturing stem cells is critical for realizing the promises of stem-cell-based regenerative medicine, including cartilage for joint repair, cardiac cells for damaged hearts, and healthy skeletal myoblasts for muscular dystrophy patients. The advance could also lead to better model systems for fundamental stem cell research.
which would have been wonderful material to add to the article, as it illustrated why "programable" stemcells are likely to become the major medical paradigm by decades end.
