domingo, 4 de agosto de 2013

Cell-targeting automata, mimicking QM, DNA analysis via Phone, brain-to-brain interface, nanoribbons, cell reprogramming, amazing microfluidics. Science Sunday. Digest 26 - 4th Aug 2013.

ORIGINAL: Mark Bruce

SciTech #ScienceSunday Digest 26 - 4th Aug 2013.

1. Molecular Automata Improve Cell Targeting.By linking specific antibodies to specific short DNA sequences termed “molecular automata” unique subpopulations of cells can be targeted and identified http://www.hss.edu/newsroom_molecular-robots-build-targeted-therapeutics.asp. In a proof-of-concept with human blood samples researchers were able to target specific subpopulations of white blood cells. The antibody component binds to the desired receptor expressed on the cell surface, while the DNA component is a linker molecule that can fluoresce. By adding a number of different “automata” you can progressively select only those cells that express those particular receptors on their surface and no others; the DNA strands from the different automata go through complementary binding due to their proximity and fluoresce, enabling them to be identified and separated. This is a great addition of modularity into cell and drug targeting technology - individual advances in drug carriers and cell targeting are now possible and complimentary.

2. Mimicking Quantum Mechanics with Fluid Dynamics.The fluidic analogue of a classic quantum experiment has been produced, but instead of electrons being confined by a circular ring of iron atoms, bouncing fluid droplets are confined in a dish http://web.mit.edu/newsoffice/2013/when-fluid-dynamics-mimic-quantum-mechanics-0729.html. In this deceptively simple experiment the fluid droplets were shown to mimic the statistical behaviour of electrons with remarkable accuracy; the same distribution appeared in both systems. This provides evidence for de Broglie’s Pilot Wave theory - at least for fluid droplets bouncing along vibrating fluid baths, driven by interfering waves produced by their own bounces. The video is worth a watch The pilot-wave dynamics of walking droplets.

3. DNA Analysis on Your Smartphone.A company called Biomeme is to launch a new smartphone docking station that plugs into your phone and makes use of its processing power to perform real-time DNA analysis http://www.medgadget.com/2013/07/mobile-real-time-dna-analysis-on-your-smartphone.html. The dock takes biological samples and allows your phone to conduct PCR on the sample and subsequently determine the presence of specific DNA sequences of interest that are linked to pathogens or other diseases. Cheap ultra-mobile and portable DNA analysis would be quite a game-changer for many applications. Detecting single DNA point-mutations is getting easier too http://www.washington.edu/news/2013/07/28/breakthrough-in-detecting-dna-mutations-could-help-treat-tuberculosis-cancer/.

4. Non-Invasive Brain-to-Brain Communication Allows Mind Control of Rat’s Tail.The first brain-to-brain interface between a human and a rat has been demonstrated and, in a proof-of-concept study allowed the human to mind-control the movement of the rat’s tail http://www.plosone.org/article/info:doi/10.1371/journal.pone.0060410. The article includes a nice embedded video showing the experimental setup of how an animal’s body was remote-controlled by someone else's brain - still very rudimentary but such capabilities will only get easier and better with time. A new technique can also measure neuronal activity at a faster rate http://blogs.princeton.edu/research/2013/07/25/a-faster-vessel-for-charting-the-brain-nature-communications/.

5. New Meniscus Lithography Creates Long Graphene Nanoribbons.Long graphene nanoribbons can now be created easily and cheaply using a new water-enabled lithographic technique that uses water or the meniscus of at a water interface as a mask http://news.rice.edu/2013/07/29/water-clears-path-for-nanoribbon-development/. The new technique allows sub-10nm nanoribbons to be constructed and built into field-effect transistors using much cheaper fabrication equipment. In future work the group aims to improve the technique to produce ribbons of uniform thickness and controllable edge state to better define the electronic properties. Graphene supercapacitors are moving along nicely http://monash.edu.au/news/show/soft-approach-leads-to-revolutionary-energy-storage.
A thin line of platinum sits atop a substrate. The metal nanowire was created with a new meniscus mask process discovered at Rice University. Image by Tour Group/Rice University

6. Computer Model Predicts How to Change Cell Differentiation.A new computer model can make accurate predictions concerning which differentiated cells can be efficiently changed into different cell types - from skin to nerve cells for example http://wwwen.uni.lu/universite/actualites/a_la_une/cells_reprogrammed_on_the_computer. This is a big step in computational biology, for producing computer-based instructions for reprogramming cells for various applications. Previously such differentiated cell conversions required a precisely delivered cocktail of factors that largely arose as a result of trial and error. Now, with the new model, this trial and error approach has been replaced by calculations that determine which genes, at what time, and in what order need to be switched on to achieve the desired results; these predictions were proved accurate in the lab.

7. Microfluidic Breakthrough: Merging, Transporting, Splitting Addressable Microdroplets.In a big step for microfluidics a new microfluidic system is able to merge, transport, and split microdroplets on the chip over long timescales and involving potentially thousands of operations on each of the hundreds of addressable microdroplets http://phys.org/news/2013-07-microfluidic-breakthrough-biotechnology.html. The droplets are addressable by each having a unique optoelectronic identifier that allows the user to monitor, at any time, what chemical operations have been performed on each droplet. The prototype system successfully manipulated and analysed microdroplets that were each loaded with thousands of bacteria - they showed that bacteria were confined to their original droplet and could not move to others.

8. Controllably Binding Together Atoms that Repel.By adding a controlled amount of energetic noise into a system atoms that normally repel one another can be made to form a strong and stable bond http://phys.org/news/2013-07-repelling-atoms.html. The addition of the controlled noise into the quantum system of the atoms, in this case from vacuum fluctuations from the electromagnetic field, induces an interference phenomenon that traps the atoms and forces them into a robust bond. The group quotes possible applications in cooling atomic quantum gases but this is tapping into a new natural phenomenon - if we can understand it more completely and achieve mastery it will open the way to interesting new technologies.

9. Guided Self-Assembling, Self-Integrating Nanowire Circuits.A new technique for growing nanowires not only allows nanowires to be grown in ordered horizontal arrays, but to be guided to automatically assemble into transistors and then subsequently “self-integrate” to form logic circuits http://phys.org/news/2013-07-growth-nanowires-self-integrated-circuits.html. The advance makes it possible to determine the arrangement of nanowires in advance to suit the desired electronic circuit that the user wishes to make. This is a great example of controlled bottom-up assembly of complex structures.

10. A Cheap Billion-Pixel Microscope.A new computational image-processing method allows a standard microscope to be fitted-out with $200 worth of add-ons and become a billion-pixel imaging system that can outperform the best standard microscopes http://www.caltech.edu/content/pushing-microscopy-beyond-standard-limits. The system allows both large fields of view and very high resolution - basic tests showed it could produce 100 times more information than the unmodified systems, and improve the performance of a 2x objective lens to the level of a 20x objective lens. The system actually measures both light intensity and phase from different angles . . . and because it measures the phase I wonder if this might find application in holography? 
The Yang lab's new microscope setup (left). A raw image taken with a 2X objective lens is shown (top right) along with the reconstructed image produced by the new microscope setup (bottom right).
Credit: Guoan Zheng. CalTech


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+ScienceSunday, with your hosts +Buddhini Samarasinghe, +Rajini Rao, +Chad Haney, +Allison Sekuler
2013-08-04
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