SciTech #ScienceSunday Digest 22 - 7th Jul 2013Mechanosynthesis prototype, MEMS atom painter, biological computer and synthetic ribosome, optical switch and twisted data.1. DNA Nanomachine for Precise Enzymatic Control.
A DNA Origami approach has resulted in the creation of a controllable tweezer-like nanomachine made out of DNA http://phys.org/news/2013-07-tiny-tweezers-precision-enzymes.html
. One end of the DNA structure has an enzyme attached and the other end has a reaction centre; the addition of one short DNA sequence causes the ends of the tweezers to spread apart and the addition of another short DNA sequence causes the ends to contract, bringing the enzyme and reaction centre together to perform the reaction in a controlled manner. Such nanosystems enabling precise positional control of chemical reactions is something long talked about by Eric Drexler for example. Imagine the group scaling this up to large arrays of these machines on a surface, able to mass-produce any desired chemical feedstock in a rapid and controlled fashion. I think this is a significant step on the road towards the full promise of nanotechnology, and yet it was so under-reported. 2. Atomic Calligraphy: MEMS That Write Nanoscale Structures.
A novel MEMS-based mask writer has been developed that allows nanoscale structures to be directly written without photoresists or other expensive techniques http://www.nanowerk.com/spotlight/spotid=31159.php
. The MEMS device acts like a shutter that, in effect, spray paints with atoms (one-at-a-time if desired); the team believe this approach will allow them to build atomic-scale devices using cost-effective manufacturing approaches. When combined with a MEMS-based evaporator and sensors to measure temperature and deposition rate this should yield a “Fab on a Chip”.3. Building a Computer with Biological Parts: A Biological Microprocessor.
Our very own +Gerd Moe-Behrens
describes in great detail how to build a general purpose biological microprocessor assembled from biological parts http://hplusmagazine.com/2013/07/03/the-biological-microprocessor-or-how-to-build-a-computer-with-biological-parts/
. As Gerd states: such a system consists of biological parts building an input / output device, an arithmetic logic unit, a control unit, memory, and wires (busses) to interconnect these components. The promise and significance of a biocomputer is that it can be used to monitor and control a biological system. This will be a truly profound capability once realised. 4. Twisted Light Boosts Optical Data Transmission.
A new fiber optic technology has been demonstrated that utilises circularly polarized (or twisted light vortices) to transmit data at 1.6 terabits per second http://www.photonics.com/Article.aspx?AID=54269
. The proof-of-concept achieved this over a distance of 1km and by being able to combine multiple frequencies that did not interfere with each other. While faster transmission speeds have been achieved in special environments such as free space, this new system can be rolled out to significantly increase broadband speeds. 5. Hyper-Magnetically-Sensitive Molecular Chains.
New and much more sensitive magnetic sensors should be possible with a new device that houses special molecular wires within ordered nanometer channels in zeolite crystals http://phys.org/news/2013-07-molecular-chains-hypersensitive-magnetic-fields.html
. The molecules have a diameter of about one nanometer, roughly the same as the crystal channels that confine them, and conduct electricity until an external magnetic field disturbs their alignment. It is thought a similar mechanism is at play in migratory birds that sense the geomagnetic field to navigate. 6. Creating & Transplanting a Rudimentary Liver from IPS Cells.
In this latest tissue engineering demonstration researchers took adult cells, turned them into stem cells, coaxed these cells to assemble and form little rudimentary liver buds, then transplanted these buds into mice whose own livers had been shut down and showed that the transplanted buds executed most of the functions of a liver and kept the mice alive http://www.technologyreview.com/news/516706/a-rudimentary-liver-is-grown-from-stem-cells/
. The possibility for human therapy is obvious, especially because the technique is applicable to other tissues, but problems remain with scale-up issues in creating large enough volumes of the cells to provide a viable therapy. 7. Building Better Graphene Nanoribbons.
Making electronic and spintronic components out of graphene nanoribbons moved a step closer with new fabrication methods that preserve edge magnetism via uniform attachment of suitable molecules along the edges of the ribbons http://www.nanowerk.com/spotlight/spotid=31128.php
. This preserves the band-gap of the graphene nanoribbons and makes the material easier to work with. Graphene’s heat conduction properties have also been shown to reduce the temperatures of computer chips by up to 25% http://www.chalmers.se/en/news/Pages/Graphene-provides-efficient-electronics-cooling.aspx
. 8. Nanotube Catalyst Outperforms Platinum.
Covering carbon nanotubes with an iron compound produces a new catalyst that outperforms conventional platinum catalysts in applications for fuel cells and metal-air batteries http://phys.org/news/2013-07-scalable-carbon-nanotube-based-catalyst-outperforming.html
. The material not only achieves significant cost and efficiency improvements but also demonstrated a much greater lifecycle with improved durability. 9. Building An All-Optical Transistor.
An all-optical switch or transistor has been created that is controlled by a single photon http://web.mit.edu/newsoffice/2013/computing-with-light-0704.html
. A single photon can cause the switch - a double nanoscale mirror system - to turn “off” or “on” allowing photons to pass or be blocked by the switch. All optical computer chips promise to be significantly faster than conventional chips, and at one photon ber bit of information this system would be significantly more energy efficient. Because the system relies on a single photon there are other very interesting and potentially transformative / disrupting possibilities too: (i) the possibility to detect a photon without destroying it, and (ii) a key enabling technology for a genuine quantum computer where photons in a superposition result in these switches / logic gates also being in a superposition. 10. Ribosomes Synthesised for The First Time.
While previous attempts have failed this new method succeeds in synthesising and assembling ribosomes that are fully functional and replicate within cells http://www.northwestern.edu/newscenter/stories/2013/06/mimicking-living-cells-synthesizing-ribosomes.html
. The work is seen as a critical step towards unraveling the systems biology of ribosome biogenesis, constructing minimal cells from defined components, and engineering ribosomes with new functions. For example, ribosomes take genetic code in the form of RNA and use that to produce proteins of a defined sequence and structure; one might want to engineer a ribosome to take a different chemical code to RNA or to build chemical sequences and structures different to amino acids and proteins. The weekly SciTech Digests are also available as a Google Currents Edition here:https://www.google.com/producer/editions/CAow4-hB/scitech_digest +ScienceSunday