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Nanodot: the original nanotechnology weblog

Active and reversible control of nanoparticle optical properties

Posted by Jim Lewis on January 3rd, 2016

This electron microscope image shows a dimer of silver plated gold nanoparticles. A layer of silver connects the particles. Credit: D. Swearer/Rice University

Nanoparticles exhibit a range of useful electronic, optical, and magnetic properties. These particles would be even more useful if such properties could be deliberately and reversibly tuned for specific purposes. Scientists have now achieved substantial progress in this direction. A hat tip to ScienceDaily for reprinting this Rice University news release written by Jade Boyd “Nanoscale drawbridges open path to color displays“:

Rice develops first method for reversible color changes with metal nanoparticles

A new method for building “drawbridges” between metal nanoparticles may allow electronics makers to build full-color displays using light-scattering nanoparticles that are similar to the gold materials that medieval artisans used to create red stained-glass.

“Wouldn’t it be interesting if we could create stained-glass windows that changed colors at the flip of a switch?” said Christy Landes, associate professor of chemistry at Rice and the lead researcher on a new study about the drawbridge method that appears this week in the open-access journal Science Advances. ["From tunable core-shell nanoparticles to plasmonic drawbridges: Active control of nanoparticle optical properties"]

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Rolling DNA-based motors increase nano-walker speeds 1000-fold

Posted by Jim Lewis on December 12th, 2015

Emory post-doctoral fellow Kevin Yehl sets up a smart-phone microscope to get a readout for the particle motion of the rolling DNA motor. This simple, low-tech method could come in handy for doing disease diagnostics in the field, for instance, detecting a single mutation in a DNA strand. Credit: Bryan Meltz, Emory Photo/Video

We have occasionally cited research in which DNA walkers move molecular components along DNA tracks. A very different approach to DNA motors has succeeded in moving micron-sized glass spheres sporting hundreds of DNA legs at 1000 times the speed of other DNA motors. A hat tip to ScienceDaily for reprinting this Emory University news article by Carol Clark “Nano-walkers take speedy leap forward with first rolling DNA-based motor“:

Physical chemists have devised a rolling DNA-based motor that’s 1,000 times faster than any other synthetic DNA motor, giving it potential for real-world applications, such as disease diagnostics. Nature Nanotechnology [abstract] is publishing the finding.

“Unlike other synthetic DNA-based motors, which use legs to ‘walk’ like tiny robots, ours is the first rolling DNA motor, making it far faster and more robust,” says Khalid Salaita, the Emory University chemist who led the research. “It’s like the biological equivalent of the invention of the wheel for the field of DNA machines.”

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Octopodal nanoparticles combine catalytic, plasmonic functions

Posted by Jim Lewis on December 11th, 2015

A scanning electron transmission microscope image shows an octopod, left, created at Rice University that has both plasmonic and catalytic abilities. At right is an illustration of the octopod, which has a gold core and a gold-palladium alloy surface. The scale bar is 50 nanometers. Courtesy of the Ringe Group/Rice University

More complex nanoparticle structures provide the opportunity to integrate multiple functions, enabling nanotechnology to play a larger role in industrial processes. A hat tip to Nanowerk for reprinting this Rice University News release “Tiny octopods catalyze bright ideas“:

Nanoscale octopods that do double duty as catalysts and plasmonic sensors are lighting a path toward more efficient industrial processes, according to a Rice University scientist.

Catalysts are substances that speed up chemical reactions and are essential to many industries, including petroleum, food processing and pharmaceuticals. Common catalysts include palladium and platinum, both found in cars’ catalytic converters. Plasmons are waves of electrons that oscillate in particles, usually metallic, when excited by light. Plasmonic metals like gold and silver can be used as sensors in biological applications and for chemical detection, among others.

Plasmonic materials are not the best catalysts, and catalysts are typically very poor for plasmonics. But combining them in the right way shows promise for industrial and scientific applications, said Emilie Ringe, a Rice assistant professor of materials science and nanoengineering and of chemistry who led the study that appears in Scientific Reports ["Resonances of nanoparticles with poor plasmonic metal tips", open access].

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Novel nanoconjugate delivers synergistic combination of microRNAs to treat cancer

Posted by Jim Lewis on December 11th, 2015

MIT researchers developed this hydrogel embedded with triple helix microRNA particles and used it to treat cancer in mice. Image: João Conde, Nuria Oliva, and Natalie Artzi

Speaking of nanomedicine, nanoparticles, microRNAs, and cancer, another research group, this time at the Broad Institute of MIT and Harvard, has demonstrated the therapeutic potential of using the right nanoconjugate to deliver the right microRNAs to tumors. A hat tip to BioScience Technology for reprinting this MIT news office release written by Anne Trafton “A new way to deliver microRNAs for cancer treatment“:

Scientists exploit gene therapy to shrink tumors in mice with an aggressive form of breast cancer.

Twenty years ago, scientists discovered that short strands of RNA known as microRNA help cells to fine-tune their gene expression. Disruption or loss of some microRNAs has been linked to cancer, raising the possibility of treating tumors by adjusting microRNA levels.

Developing such treatments requires delivering microRNA to tumors, which has proven difficult. However, researchers from MIT have now shown that by twisting RNA strands into a triple helix and embedding them in a biocompatible gel, they can not only deliver the strands efficiently but also use them to shrink aggressive tumors in mice.

Using this technique, the researchers dramatically improved cancer survival rates by simultaneously turning on a tumor-suppressing microRNA and de-activating one that causes cancer. They believe their approach could also be used for delivering other types of RNA, as well as DNA and other therapeutic molecules.

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Ultrasensitive microRNA assay with nanosensor to detect cancer

Posted by Jim Lewis on December 10th, 2015

The cancer-specific microRNA miR-10b hybridizes to DNA immobilized on a gold nanoprism. Credit: Joshi et al. ACS Nano DOI: 10.1021/acsnano.5b04527

Nanotechnology will increasingly contribute to medicine through the development of increasingly complex, computer-controlled nanorobots (such as these early DNA origami-based prototypes we cited here and here). But even very simple devices exploiting nanoparticle-based molecular interactions are looking very promising. For example, from the Indiana University-Purdue University Indianapolis Newsroom “Nanotechnology-based sensor developed to measure microRNAs in blood, speed cancer detection“:

A simple, ultrasensitive microRNA sensor developed and tested by researchers from the School of Science at Indiana University-Purdue University Indianapolis, the IU School of Medicine, and the Indiana University Melvin and Bren Simon Cancer Center holds promise for the design of new diagnostic strategies and, potentially, for the prognosis and treatment of pancreatic and other cancers.

In a study published in the November issue of ACS Nano ["Label-free nanoplasmonic-based short noncoding RNA sensing at attomolar concentrations allows for quantitative and highly specific assay of microRNA-10b in biological fluids and circulating exosomes" open access article], a peer-reviewed journal of the American Chemical Society focusing on nanoscience and nanotechnology research, the IUPUI researchers describe their design of the novel, low-cost, nanotechnology-enabled reusable sensor. They also report on the promising results from tests of the sensor’s ability to identify pancreatic cancer or indicate the existence of a benign condition by quantifying changes in levels of microRNA signatures linked to pancreatic cancer. MicroRNAs are small molecules of RNA that regulate how larger RNA molecules lead to protein expression. As such, microRNAs are very important in biology and disease states.

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Using DNA nanotechnology to position molecules with atomic precision

Posted by Jim Lewis on December 9th, 2015

Concept of a high-resolution DNA positioning device. Credit: JJ Funke & H Dietz Nature Nanotechnology doi: 10.1038/nnano.2015.240

The powerful and elegant molecular recognition code that makes possible double helical DNA has also made scaffolded DNA origami and its parent field, structural DNA nanotechnology, probably the most widespread and useful approach to bottom-up molecular nanotechnology. The 2-nm diameter of the DNA helix leads to the suspicion, however, that the ultimate precision obtainable with these technologies might not be much better than 5 nm, more than an order of magnitude less precise than atomic precision. A paper published two months ago, however, demonstrates much finer control using a DNA hinge with “adjuster helices” to control the angle of the hinge. The abstract (reference numbers omitted) from “Placing molecules with Bohr radius resolution using DNA origami“:

Molecular self-assembly with nucleic acids can be used to fabricate discrete objects with defined sizes and arbitrary shapes … . It relies on building blocks that are commensurate to those of biological macromolecular machines and should therefore be capable of delivering the atomic-scale placement accuracy known today only from natural and designed proteins …. However, research in the field has predominantly focused on producing increasingly large and complex, but more coarsely defined, objects … and placing them in an orderly manner on solid substrates … . So far, few objects afford a design accuracy better than 5 nm … , and the subnanometre scale has been reached only within the unit cells of designed DNA crystals … . Here, we report a molecular positioning device made from a hinged DNA origami object in which the angle between the two structural units can be controlled with adjuster helices. To test the positioning capabilities of the device, we used photophysical and crosslinking assays that report the coordinate of interest directly with atomic resolution. Using this combination of placement and analysis, we rationally adjusted the average distance between fluorescent molecules and reactive groups from 1.5 to 9 nm in 123 discrete displacement steps. The smallest displacement step possible was 0.04 nm, which is slightly less than the Bohr radius. The fluctuation amplitudes in the distance coordinate were also small (±0.5 nm), and within a factor of two to three of the amplitudes found in protein structures … .

The Bohr radius is the most probable distance between the proton and the electron of a hydrogen atom in its ground state, and is approximately 52.9 pm (0.0529 nm). This work from Hendrik Dietz’s group at the Technical University of Munich, Germany, continues his work on dynamic nanomachines from DNA nanotechnology that we cited last spring. For additional information about the new paper, see:

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Single-molecule light-driven nanosubmarine

Posted by Jim Lewis on December 5th, 2015

Rice University scientists have created light-driven, single-molecule submersibles that contain just 244 atoms. (Illustration by Loïc Samuel/Rice University)

Recently we noted the accomplishments of James Tour, winner of the 2008 Foresight Institute Feynman Prize in the Experimental category, and his collaborators implementing a nanomaterial incorporating single-atom catalysts. Their most recent accomplishment is a single-molecule nanosubmarine. A hat tip to Nanotechnology Now for reprinting this Rice University news release “Rice makes light-driven nanosubmarine“:

Speedy single-molecule submersibles are a first

Though they’re not quite ready for boarding a lá “Fantastic Voyage,” nanoscale submarines created at Rice University are proving themselves seaworthy.

Each of the single-molecule, 244-atom submersibles built in the Rice lab of chemist James Tour has a motor powered by ultraviolet light. With each full revolution, the motor’s tail-like propeller moves the sub forward 18 nanometers.

And with the motors running at more than a million RPM, that translates into speed. Though the sub’s top speed amounts to less than 1 inch per second, Tour said that’s a breakneck pace on the molecular scale.

“These are the fastest-moving molecules ever seen in solution,” he said.

Expressed in a different way, the researchers reported this month in the American Chemical Society journal Nano Letters [abstract] that their light-driven nanosubmersibles show an “enhancement in diffusion” of 26 percent. That means the subs diffuse, or spread out, much faster than they already do due to Brownian motion, the random way particles spread in a solution.

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Atomic precision in sculpting 3-D objects

Posted by Jim Lewis on December 3rd, 2015

ORNL researchers used a new scanning transmission electron microscopy technique to sculpt 3-D nanoscale features in a complex oxide material. (credit: Department of Energy’s Oak Ridge National Laboratory)

Atomic-level sculpting of a crystalline oxide from a metastable amorphous oxide film has been demonstrated using a scanning transmission electron microscope. A hat tip to KurzweilAI for reporting this Oak Ridge National Laboratory news release “New electron microscopy method sculpts 3-D structures at atomic level“:

Electron microscopy researchers at the Department of Energy’s Oak Ridge National Laboratory have developed a unique way to build 3-D structures with finely controlled shapes as small as one to two billionths of a meter.

The ORNL study published in the journal Small demonstrates how scanning transmission electron microscopes, normally used as imaging tools, are also capable of precision sculpting of nanometer-sized 3-D features in complex oxide materials.

By offering single atomic plane precision, the technique could find uses in fabricating structures for functional nanoscale devices such as microchips. The structures grow epitaxially, or in perfect crystalline alignment, which ensures that the same electrical and mechanical properties extend throughout the whole material.

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Generating hydrogen with single atom catalysts

Posted by Jim Lewis on November 13th, 2015

Disordered graphitic carbon doped with nitrogen and augmented with cobalt atoms serves as an efficient, robust catalyst for hydrogen separation from water. The material discovered at Rice University could challenge more expensive platinum-based catalysts. (Credit: Tour Group/Rice University)

James Tour, winner of the 2008 Foresight Institute Feynman Prize in the Experimental category, and his collaborators continue to bring forward a variety of promising applications based upon graphene and other nanostructured materials. Recently we cited a nanotechnology computer memory breakthrough and before that a flexible supercapacitor from stacked nanomaterial. A hat tipp to Nanotechnology Now for reprinting this Rice University news release written by Mike Williams “Cobalt atoms on graphene a powerful combo“:

Rice University catalyst holds promise for clean, inexpensive hydrogen production

Graphene doped with nitrogen and augmented with cobalt atoms has proven to be an effective, durable catalyst for the production of hydrogen from water, according to scientists at Rice University.

The Rice lab of chemist James Tour and colleagues at the Chinese Academy of Sciences, the University of Texas at San Antonio and the University of Houston have reported the development of a robust, solid-state catalyst that shows promise to replace expensive platinum for hydrogen generation.

Catalysts can split water into its constituent hydrogen and oxygen atoms, a process required for fuel cells. The latest discovery, detailed in Nature Communications [Open Access], is a significant step toward lower-cost catalysts for energy production, according to the researchers.

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Architecture for atomically precise quantum computer in silicon

Posted by Jim Lewis on November 9th, 2015

Australian researchers have figured out a way to deal with errors in quantum computers. Credit: UNSW Australia

All applications of nanotechnology will eventually benefit from the movement of current methods of nanofabrication toward atomic precision, eventually producing a general purpose method for high throughput atomically precise manufacturing. But perhaps the first and most important application in which atomically precise fabrication will make a critically important contribution is quantum computing. Back in 2012 we noted successes of Australian researchers in atomically-precise positioning of a single atom transistor and in writing of a single-atom qubit in silicon. Also in 2012 Foresight Update reported on a workshop sponsored by the Atomically Precise Manufacturing Consortium, NIST, and Zyvex Labs to discuss the fabrication of such atomically precise devices. Now Australian researchers have provided a blueprint for operational quantum computers. A hat tip to Nanotechnology-Now for reprinting this University of New South Wales news release written by Myles Gough “Researchers design architecture for a quantum computer in silicon“:

Researchers at UNSW and the University of Melbourne have designed a 3D silicon chip architecture based on single atom quantum bits, providing a blueprint to build a large-scale quantum computer.

Australian scientists have designed a 3D silicon chip architecture based on single atom quantum bits, which is compatible with atomic-scale fabrication techniques – providing a blueprint to build a large-scale quantum computer.

Scientists and engineers from the Australian Research Council Centre of Excellence for Quantum Computation and Communication Technology (CQC2T), headquartered at UNSW, are leading the world in the race to develop a scalable quantum computer in silicon – a material well-understood and favoured by the trillion-dollar computing and microelectronics industry.

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One-directional rotation in a new artificial molecular motor

Posted by Jim Lewis on November 5th, 2015

Credit: Feringa Group, University of Groningen

Biological molecular motors are amazing nanomachines that make all life possible, but even smaller artificial molecular motors based upon organic chemistry instead of biological polymers continue to become more complex and better controlled. A hat tip to Nanowerk for reprinting this news release from the University of Groningen in The Netherlands “New molecular motor mimics two wheels on an axle“:

University of Groningen scientists led by Professor of Organic Chemistry Ben Feringa have designed a new type of molecular motor. In contrast to previous designs, this molecule is symmetrical. It comprises two parts, which are connected by a central ‘axle’ and rotate in opposite directions, just like the wheels of a car. The results, which were published … in the journal Nature Chemistry [abstract], would be ideal for nano transport systems.

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DNA nanomachine lights up to diagnose diseases

Posted by Jim Lewis on November 2nd, 2015

The light-generating DNA antibody detecting nanomachine is illustrated here in action, bound to an antibody. Credit: Marco Tripodi

As current day nanotechnology makes incremental advances in technologies that advance the goal of atomic precision in control of the structure of matter, such as DNA nanotechnology, such advances sometimes also provide opportunities to apply primitive nanomachines to current needs. A hat tip to KurzweilAI for reporting such an advance announced by the newsroom of the Université de Montréal “Detecting HIV diagnostic antibodies with DNA nanomachines“:

New research may revolutionize the slow, cumbersome and expensive process of detecting the antibodies that can help with the diagnosis of infectious and auto-immune diseases such as rheumatoid arthritis and HIV. An international team of researchers have designed and synthesized a nanometer-scale DNA “machine” whose customized modifications enable it to recognize a specific target antibody. Their new approach, which they described this month in Angewandte Chemie [abstract], promises to support the development of rapid, low-cost antibody detection at the point-of-care, eliminating the treatment initiation delays and increasing healthcare costs associated with current techniques.

The binding of the antibody to the DNA machine causes a structural change (or switch), which generates a light signal. The sensor does not need to be chemically activated and is rapid – acting within five minutes – enabling the targeted antibodies to be easily detected, even in complex clinical samples such as blood serum.

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Chirality-assisted synthesis a new tool for nanotechnology

Posted by Jim Lewis on October 30th, 2015

Credit: Schneebeli research group, University of Vermont.

New tools that provide chemists with greater ability to build more complex molecules are important steps on the path to atomically precise manufacturing. The newsroom of the University of Vermont reports a “fundamentally new way to control the shape of molecules.” “Scientists Build Wrench 1.7 Nanometers Wide“:

Hold up your two hands. They are identical in structure, but mirror opposites. No matter how hard you try, they can’t be superimposed onto each other. Or, as chemists would say, they have “chirality,” from the Greek word for hand. A molecule that is chiral comes in two identical, but opposite, forms–just like a left and right hand.

University of Vermont chemist Severin Schneebeli has invented a new way to use chirality to make a wrench. A nanoscale wrench. His team’s discovery allows them to precisely control nanoscale shapes and holds promise as a highly accurate and fast method of creating customized molecules.

This use of “chirality-assisted synthesis” is a fundamentally new approach to control the shape of large molecules–one of the foundational needs for making a new generation of complex synthetic materials, including polymers and medicines.

The UVM team’s results were presented online, September 9, in the top-ranked chemistry journal Angewandte Chemie [abstract].

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Surface assisted self-assembly of DNA origami nanostructures

Posted by Jim Lewis on October 26th, 2015

Credit: Suzuki et al. Institute for Integrated Cell-Material Sciences, Kyoto University.

The frequent improvements and extensions of scaffolded DNA origami testify to the usefulness of this technology. A hat tip to KurzweilAI for reporting this advance from Kyoto University organizing DNA origami nanostructures into micrometer-scale 2D arrays “Using DNA origami to build nanodevices of the future“:

Scientists have developed a method, using a double layer of lipids, which facilitates the assembly of DNA origami units, bringing us one-step closer to organized DNA nanomachines.

Scientists have been studying ways to use synthetic DNA as a building block for smaller and faster devices. DNA has the advantage of being inherently “coded”. Each DNA strand is formed of one of four “codes” that can link to only one complementary code each, thus binding two DNA strands together. Scientists are using this inherent coding to manipulate and “fold” DNA to form “origami nanostructures”: extremely small two- and three-dimensional shapes that can then be used as construction material to build nanodevices such as nanomotors for use in targeted drug delivery inside the body.

Despite progress that has been made in this field, assembling DNA origami units into larger structures remains challenging.

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Free online edition of The Feynman Lectures on Physics

Posted by Jim Lewis on October 25th, 2015

Richard P. Feynman (1918-1988)

Free to read online edition of The Feynman Lectures on Physics

A core component of Foresight’s founding vision is Richard Feynman’s 1959 talk “There’s Plenty of Room at the Bottom” in which he envisioned tiny machines building complex products with atomic precision. “Put the atoms down where the chemist says, and so you make the substance,” Feynman said. Foresight annually awards the Foresight Institute Feynman Prizes: Experimental and Theory “to researchers whose recent work have most advanced the achievement of Feynman’s goal for nanotechnology: the construction of atomically-precise products through the use of molecular machine systems.” Besides sharing a Nobel Prize for Physics Richard Feynman was also well-known as an exceptionally effective teacher. A year ago we were privileged to communicate the availability, through the efforts of Mr. John Neer, of 400 hours of Richard Feynman’s Hughes Lectures. An article on The Smithsonian publicizes the free to read online edition of The Feynman Lectures on Physics, long recognized as the definitive physics textbook. Since well-understood physical law is the foundation for the expectation that High-Throughput Atomically Precise Manufacturing is feasible, a sound understanding of basic physics provides an excellent foundation for thinking about the future of technology. Now arguably the best resources toward that understanding are available online for free.
—James Lewis, PhD

Conference video: New Methods of Exploring, Analyzing, and Predicting Molecular Interactions

Posted by Jim Lewis on October 8th, 2015

Credit: Art Olson

A select set of videos from the 2013 Foresight Technical Conference: Illuminating Atomic Precision, held January 11-13, 2013 in Palo Alto, have been made available on vimeo. Videos have been posted of those presentations for which the speakers have consented. Other presentations contained confidential information and will not be posted.

The second speaker at the Computation and Molecular Nanotechnolgies session, Art Olson, presented “New Methods of Exploring, Analyzing, and Predicting Molecular Interactions” . https://vimeo.com/63008844 – video length 46:17. Prof. Olson began with three simple points on interacting with and understanding the nanoscale world: (1) human interaction—how we understand something that we can’t see directly; (2) how we integrate data from lots of different sources to form a picture of what is happening at the nanoscale; (3) how we develop software tools to move forward in these areas.

Olson recommended that we should use all of our senses as much as we can because we learn in different ways; we see in different ways; we understand in different ways. Similarly, there is no one data source that gives us a complete picture of the molecular world, so we have to synthesize across scales, and we have to synthesize across methods. With software, collaboration is important, because if we can bridge disciplines rather than reinvent what already exists, we can move a lot faster.

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Foresight co-founder on the future of the human lifespan

Posted by Jim Lewis on October 6th, 2015

Credit: The Optimized Geek and Stephan Spencer

The October 1, 2015 podcast of The Optimized Geek: Reboot Your Life, with host SEO expert, author, and professional speaker Stephan Spencer featured Foresight Co-Founder and Past President Christine Peterson: A Glimpse at the Future Lifespan of Humans (55 minutes).

Christine explained the development of nanotechnology in three stages. Currently we are moving from the first stage focus on nanomaterials, like stain-resistant pants, into the second phase, dominated by nanoscale devices. The most exciting change will come with the third stage, in which systems of molecular machines will operate with atomic precision.

In responding to a question from Spencer on what we might see in the next ten years, Peterson suggested that although nanotechnology in that time frame would still be mostly about nanomaterials and simple nanodevices, one of the most interesting applications would be in health, giving the example of more effective diagnosis, imaging, and treatment of cancer through the enhanced targeting specificity of nanomaterials and nanodevices.

What might advanced nanotechnology look like 30 years from now? Peterson began with the question: What limits do the laws of physics set on what we can build with systems of molecular machines able to build with atomic precision, including inside the human body? One of many applications would be correcting DNA mistakes and mutations cell by cell. Other targets could be damaged proteins and plaques from Alzheimers, etc.

With this level of technology, lifespans would not be limited by aging or traditional diseases, but only by accidents that destroyed the brain, leading to estimated lifespans on the order of 10,000 years. With technology to record the molecular structure of brain, back-up copies of individual brains could be made, eliminating even the 10,000 year limit.

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Nanotechnology carries gene editing package into cells

Posted by Jim Lewis on October 2nd, 2015

Credit: North Carolina State University

DNA nanotechnology has been used to deliver to a cell, not just drug molecules, but an entire gene editing system. A hat tip to Bioscience Technology for reprinting this news release from North Carolina State University “Researchers Use DNA ‘Clews’ to Shuttle CRISPR-Cas9 Gene-Editing Tool into Cells“:

Researchers from North Carolina State University and the University of North Carolina at Chapel Hill have for the first time created and used a nanoscale vehicle made of DNA to deliver a CRISPR-Cas9 gene-editing tool into cells in both cell culture and an animal model.

The CRISPR-Cas system, which is found in bacteria and archaea, protects bacteria from invaders such as viruses. It does this by creating small strands of RNA called CRISPR RNAs, which match DNA sequences specific to a given invader. When those CRISPR RNAs find a match, they unleash Cas9 proteins that cut the DNA. In recent years, the CRISPR-Cas system has garnered a great deal of attention in the research community for its potential use as a gene editing tool – with the CRISPR RNA identifying the targeted portion of the relevant DNA, and the Cas protein cleaving it.

But for Cas9 to do its work, it must first find its way into the cell. This work focused on demonstrating the potential of a new vehicle for directly introducing the CRISPR-Cas9 complex – the entire gene-editing tool – into a cell.

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DNA nanotechnology guides assembling cells into 'Organoids'

Posted by Jim Lewis on September 30th, 2015

Credit: Todhunter et al. and Nature Methods

Our principal interest in DNA nanotechnology is based on using the easily coded molecular recognition properties of DNA to arrange molecules and other nanometer scale structures; however, DNA is also proving useful for arranging whole cells for a new branch of nanomedicine: the three-dimensional printing of human tissue. A hat tip to Bioscience Technology for reprinting this University of California at San Francisco news release written by Nicholas Weiler “DNA-Guided 3-D Printing of Human Tissue is Unveiled“:

Technique Produces ‘Organoids’ Useful in Cancer Research, Drug Screening

A UCSF-led team has developed a technique to build tiny models of human tissues, called organoids, more precisely than ever before using a process that turns human cells into a biological equivalent of LEGO bricks. These mini-tissues in a dish can be used to study how particular structural features of tissue affect normal growth or go awry in cancer. They could be used for therapeutic drug screening and to help teach researchers how to grow whole human organs.

The new technique — called DNA Programmed Assembly of Cells (DPAC) and reported in the journal Nature Methods [abstract, PDF courtesy of Prof. Gartner's publications page] — allows researchers to create arrays of thousands of custom-designed organoids, such as models of human mammary glands containing several hundred cells each, which can be built in a matter of hours.

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Catalytic micromotors demonstrate carbon dioxide removal from water

Posted by Jim Lewis on September 29th, 2015

Image credit: Laboratory for Nanobioelectronics, UC San Diego Jacobs School of Engineering.

Visionary proposals for advanced medical nanorobots often picture µm scale submarine-like devices navigating the bloodstream. Those are probably still a couple decades away, but prototypes of conceptually much simpler six µm scale motors that could someday navigate the oceans to sequester carbon dioxide have been demonstrated. A hat tip to Science Daily for reprinting this news release from the University of California at San Diego Jacobs School of Engineering”Tiny carbon-capturing motors may help tackle rising carbon dioxide levels“:

Machines that are much smaller than the width of a human hair could one day help clean up carbon dioxide pollution in the oceans. Nanoengineers at the University of California, San Diego have designed enzyme-functionalized micromotors that rapidly zoom around in water, remove carbon dioxide and convert it into a usable solid form.

The proof of concept study represents a promising route to mitigate the buildup of carbon dioxide, a major greenhouse gas in the environment, said researchers. The team, led by distinguished nanoengineering professor and chair Joseph Wang, published the work this month in the journal Angewandte Chemie [abstract].

“We’re excited about the possibility of using these micromotors to combat ocean acidification and global warming,” said Virendra V. Singh, a postdoctoral scientist in Wang’s research group and a co-first author of this study.

In their experiments, nanoengineers demonstrated that the micromotors rapidly decarbonated water solutions that were saturated with carbon dioxide. Within five minutes, the micromotors removed 90 percent of the carbon dioxide from a solution of deionized water. The micromotors were just as effective in a sea water solution and removed 88 percent of the carbon dioxide in the same timeframe.

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