Tag Archives: MIT

DNA damage from engineered nanoparticles (zinc oxide, silver, silicon dioxide, cerium oxide and iron oxide)

Before launching into this research, there are a few provisos. This work was done in a laboratory, a highly specialized environment that does not mimic real-life conditions, and performed on animal cells (a hamster’s). As well, naturally occurring nanoparticles were not included (my Nov. 24, 2011 post has some information about naturally occurring nanomaterials including nanosilver which we have been ingesting for centuries).

That said, the studies from the Massachusetts Institute of Techology (MIT) and the Harvard School of Public Health (HSPH; last mentioned here in an April 2, 2014 post) are concerning (from an April 9, 2014 news item on Azonano).

A new study from MIT and the Harvard School of Public Health (HSPH) suggests that certain nanoparticles can also harm DNA. This research was led by Bevin Engelward, a professor of biological engineering at MIT, and associate professor Philip Demokritou, director of HSPH’s Center for Nanotechnology and Nanotoxicology.

The researchers found that zinc oxide nanoparticles, often used in sunscreen to block ultraviolet rays, significantly damage DNA. Nanoscale silver, which has been added to toys, toothpaste, clothing, and other products for its antimicrobial properties, also produces substantial DNA damage, they found.

The findings, published in a recent issue of the journal ACS Nano, relied on a high-speed screening technology to analyze DNA damage. This approach makes it possible to study nanoparticles’ potential hazards at a much faster rate and larger scale than previously possible.

More details about current testing requirements and the specific nanoparticles studied can be found in the April 8, 2014 MIT news release, which originated the news item,

The Food and Drug Administration does not require manufacturers to test nanoscale additives for a given material if the bulk material has already been shown to be safe. However, there is evidence that the nanoparticle form of some of these materials may be unsafe: Due to their immensely small size, these materials may exhibit different physical, chemical, and biological properties, and penetrate cells more easily.

“The problem is that if a nanoparticle is made out of something that’s deemed a safe material, it’s typically considered safe. There are people out there who are concerned, but it’s a tough battle because once these things go into production, it’s very hard to undo,” Engelward says.

The researchers focused on five types of engineered nanoparticles — silver, zinc oxide, iron oxide, cerium oxide, and silicon dioxide (also known as amorphous silica) — that are used industrially. Some of these nanomaterials can produce free radicals called reactive oxygen species, which can alter DNA. Once these particles get into the body, they may accumulate in tissues, causing more damage.

“It’s essential to monitor and evaluate the toxicity or the hazards that these materials may possess. There are so many variations of these materials, in different sizes and shapes, and they’re being incorporated into so many products,” says Christa Watson, a postdoc at HSPH and the paper’s lead author. “This toxicological screening platform gives us a standardized method to assess the engineered nanomaterials that are being developed and used at present.”

The researchers hope that this screening technology could also be used to help design safer forms of nanoparticles; they are already working with partners in industry to engineer safer UV-blocking nanoparticles. Demokritou’s lab recently showed that coating zinc oxide particles with a nanothin layer of amorphous silica can reduce the particles’ ability to damage DNA.

Given that Demokritou was part of a team that recently announced a new testing platform (Volumetric Centrifugation Method [VCM]) for nanoparticles as mentioned in my April 2, 2014 post, I was a little curious about the  platform for this project ( the CometChip) and, as always, curious about the results for all the tested engineered nanoparticles (Note: A link has been removed), from the news release,

Until now, most studies of nanoparticle toxicity have focused on cell survival after exposure. Very few have examined genotoxicity, or the ability to damage DNA — a phenomenon that may not necessarily kill a cell, but one that can lead to cancerous mutations if the damage is not repaired.

A common way to study DNA damage in cells is the so-called “comet assay,” named for the comet-shaped smear that damaged DNA forms during the test. The procedure is based on gel electrophoresis, a test in which an electric field is applied to DNA placed in a matrix, forcing the DNA to move across the gel. During electrophoresis, damaged DNA travels farther than undamaged DNA, producing a comet-tail shape.

Measuring how far the DNA can travel reveals how much DNA damage has occurred. This procedure is very sensitive, but also very tedious.

In 2010, Engelward and MIT professor Sangeeta Bhatia developed a much more rapid version of the comet assay, known as the CometChip. Using microfabrication technology, single cells can be trapped in tiny microwells within the matrix. This approach makes it possible to process as many as 1,000 samples in the time that it used to take to process just 30 samples — allowing researchers to test dozens of experimental conditions at a time, which can be analyzed using imaging software.

Wolfgang Kreyling, an epidemiologist at the German Research Center for Environmental Health who was not involved in the study, says this technology should help toxicologists catch up to the rapid rate of deployment of engineered nanoparticles (ENPs).

“High-throughput screening platforms are desperately needed,” Kreyling says. “The proposed approach will be not only an important tool for nanotoxicologists developing high-throughput screening strategies for the assessment of possible adverse health effects associated with ENPs, but also of great importance for material scientists working on the development of novel ENPs and safer-by-design approaches.”

Using the CometChip, the MIT and HSPH researchers tested the nanoparticles’ effects on two types of cells that are commonly used for toxicity studies: a type of human blood cells called lymphoblastoids, and an immortalized line of Chinese hamster ovary cells.

Zinc oxide and silver produced the greatest DNA damage in both cell lines. At a concentration of 10 micrograms per milliliter — a dose not high enough to kill all of the cells — these generated a large number of single-stranded DNA breaks.

Silicon dioxide, which is commonly added during food and drug production, generated very low levels of DNA damage. Iron oxide and cerium oxide also showed low genotoxicity.

Happily the researchers are taking a pragmatic approach to the results (from the news release),

More studies are needed to determine how much exposure to metal oxide nanoparticles could be unsafe for humans, the researchers say.

“The biggest challenge we have as people concerned with exposure biology is deciding when is something dangerous and when is it not, based on the dose level. At low levels, probably these things are fine,” Engelward says. “The question is: At what level does it become problematic, and how long will it take for us to notice?”

One of the areas of greatest concern is occupational exposure to nanoparticles, the researchers say. Children and fetuses are also potentially at greater risk because their cells divide more often, making them more vulnerable to DNA damage.

The most common routes that engineered nanoparticles follow into the body are through the skin, lungs, and stomach, so the researchers are now investigating nanoparticle genotoxicity on those cell types. They are also studying the effects of other engineered nanoparticles, including metal oxides used in printer and photocopier toner, which can become airborne and enter the lungs.

Kudos to the writer for the clarity and care shown here (I think it’s Anne Trafton but MIT is not including bylines as it did previously, so I’m uncertain).

Here’s a link to and a citation for the research paper,

High-Throughput Screening Platform for Engineered Nanoparticle-Mediated Genotoxicity Using CometChip Technology by Christa Watson, Jing Ge, Joel Cohen, Georgios Pyrgiotakis, Bevin P. Engelward, and Philip Demokritou. ACS Nano, 2014, 8 (3), pp 2118–2133 DOI: 10.1021/nn404871p Publication Date (Web): March 11, 2014
Copyright © 2014 American Chemical Society

This article is behind a paywall.

Bioceramic armour: tough and clear

This story about a mollusk and its armour eventually led me back to one of my favourite science writers, David L. Chandler at the Massachusetts Institute of Technology (MIT). First, here’s an excerpt from a March 30, 2014 news item on ScienceDaily,

The shells of a sea creature, the mollusk Placuna placenta, are not only exceptionally tough, but also clear enough to read through. Now, researchers at MIT have analyzed these shells to determine exactly why they are so resistant to penetration and damage — even though they are 99 percent calcite, a weak, brittle mineral.

The shells’ unique properties emerge from a specialized nanostructure that allows optical clarity, as well as efficient energy dissipation and the ability to localize deformation, the researchers found. The results are published this week in the journal Nature Materials, in a paper co-authored by MIT graduate student Ling Li and professor Christine Ortiz.

A March 30, 2014 MIT press release (I’m not positive Chandler wrote this but he is the press contact) describes both the engineered bioceramic armour and the mollusk’s naturally occurring armour,

Engineered ceramic-based armor, while designed to resist penetration, often lacks the ability to withstand multiple blows, due to large-scale deformation and fracture that can compromise its structural integrity, Ortiz says. In transparent armor systems, such deformation can also obscure visibility.

Creatures that have evolved natural exoskeletons — many of them ceramic-based — have developed ingenious designs that can withstand multiple penetrating attacks from predators. The shells of a few species, such as Placuna placenta, are also optically clear.

To test exactly how the shells — which combine calcite with about 1 percent organic material — respond to penetration, the researchers subjected samples to indentation tests, using a sharp diamond tip in an experimental setup that could measure loads precisely. They then used high-resolution analysis methods, such as electron microscopy and diffraction, to examine the resulting damage.

The material initially isolates damage through an atomic-level process called “twinning” within the individual ceramic building blocks: A crystal breaks up into a pair of mirror-image regions that share a common boundary, rather like a butterfly’s wings. This twinning process occurs all around the stressed region, helping to form a kind of boundary that keeps the damage from spreading outward.

The MIT researchers found that twinning then activates “a series of additional energy-dissipation mechanisms … which preserve the mechanical and optical integrity of the surrounding material,” Li says. This produces a material that is 10 times more efficient in dissipating energy than the pure mineral, Li adds.

The properties of this natural armor make it a promising template for the development of bio-inspired synthetic materials for both commercial and military applications — such as eye and face protection for soldiers, windows and windshields, and blast shields, Ortiz says.

Huajian Gao, a professor of engineering at Brown University who was not involved in this research, calls it “an excellent and elegant piece of work.” He says it “successfully demonstrates the effectiveness of nanoscale deformation twins in energy dissipation in bioceramics, and should be able to inspire and guide the development of manmade ceramic materials.” He adds, “As a first-of-its-kind [demonstration of] the effectiveness of deformation twins in natural materials, this work should have huge practical impact.”

The work was supported by the National Science Foundation; the U.S. Army Research Office through the MIT Institute for Soldier Nanotechnologies; the National Security Science and Engineering Faculty Fellowships Program; and the Office of the Assistant Secretary of Defense for Research and Engineering.

The researchers have produced an image showing how the mollusk shell reacts to being damaged,

A Scanning Electron Microscope (SEM) image of the region surrounding an indentation the researchers made in a piece of shell from Placuna placenta. The image shows the localization of damage to the area immediately surrounding the stress. Image: Ling Li and James C. Weaver. Courtesy: MIT

A Scanning Electron Microscope (SEM) image of the region surrounding an indentation the researchers made in a piece of shell from Placuna placenta. The image shows the localization of damage to the area immediately surrounding the stress.
Image: Ling Li and James C. Weaver. Courtesy: MIT

Here’s a link to and a citation for the paper,

Pervasive nanoscale deformation twinning as a catalyst for efficient energy dissipation in a bioceramic armour by Ling Li & Christine Ortiz. Nature Materials (2014) doi:10.1038/nmat3920 Published online 30 March 2014

This paper is behind a paywall.

UK’s National Physical Laboratory reaches out to ‘BioTouch’ MIT and UCL

This March 27, 2014 news item on Azonano is an announcement for a new project featuring haptics and self-assembly,

NPL (UK’s National Physical Laboratory) has started a new strategic research partnership with UCL (University College of London) and MIT (Massachusetts Institute of Technology) focused on haptic-enabled sensing and micromanipulation of biological self-assembly – BioTouch.

The NPL March 27, 2014 news release, which originated the news item, is accompanied by a rather interesting image,

A computer operated dexterous robotic hand holding a microscope slide with a fluorescent human cell (not to scale) embedded into a synthetic extracellular matrix. Courtesy: NPL

A computer operated dexterous
robotic hand holding a microscope
slide with a fluorescent human cell
(not to scale) embedded into a
synthetic extracellular matrix. Courtesy: NPL

The news release goes on to describe the BioTouch project in more detail (Note: A link has been removed),

The project will probe sensing and application of force and related vectors specific to biological self-assembly as a means of synthetic biology and nanoscale construction. The overarching objective is to enable the re-programming of self-assembled patterns and objects by directed micro-to-nano manipulation with compliant robotic haptic control.

This joint venture, funded by the European Research Council, EPSRC and NPL’s Strategic Research Programme, is a rare blend of interdisciplinary research bringing together expertise in robotics, haptics and machine vision with synthetic and cell biology, protein design, and super- and high-resolution microscopy. The research builds on the NPL’s pioneering developments in bioengineering and imaging and world-leading haptics technologies from UCL and MIT.

Haptics is an emerging enabling tool for sensing and manipulation through touch, which holds particular promise for the development of autonomous robots that need to perform human-like functions in unstructured environments. However, the path to all such applications is hampered by the lack of a compliant interface between a predictably assembled biological system and a human user. This research will enable human directed micro-manipulation of experimental biological systems using cutting-edge robotic systems and haptic feedback.

Recently the UK government has announced ‘eight great technologies’ in which Britain is to become a world leader. Robotics, synthetic biology, regenerative medicine and advanced materials are four of these technologies for which this project serves as a merging point providing thus an excellent example of how multidisciplinary collaborative research can shape our future.

If it read this rightly, it means they’re trying to design systems where robots will work directly with materials in the labs while humans direct the robots’ actions from a remote location. My best example of this (it’s not a laboratory example) would be of a surgery where a robot actually performs the work while a human directs the robot’s actions based on haptic (touch) information the human receives from the robot. Surgeons don’t necessarily see what they’re dealing with, they may be feeling it with their fingers (haptic information). In effect, the robot’s hands become an extension of the surgeon’s hands. I imagine using a robot’s ‘hands’ would allow for less invasive procedures to be performed.

Nicholas Negroponte and Chris Hadfield at TED 2014′s Session 1: Liftoff

Nicholas Negroponte opened the first TED conference in 1984 and has come back for the 30th anniversary. Here’s his TED biography,

The founder of the MIT [Massachusetts Institute of Technology] Media Lab, Nicholas Negroponte pushed the edge of the information revolution as an inventor, thinker and angel investor. He’s the driving force behind One Laptop per Child, building computers for children in the developing world.

media.mit.edu

Negroponte discusses what has changed over the years. When he first started in the 1970s no one thought you’d ever use a touchscreen and putting your fingers on the screen was considered silly. This sort of thinking (touchscreens) is what went into the development of MIT’s Media Lab. He seems to be highlighting some of the high points of his thinking. He finds some of today’s internet of Things thinking to be pathetic (he references some of the sessions earlier today). He (?) started Wired magazine. Negroponte has gotten more interested in computers and learning over the years. He compares iteration to learning and mentions One Laptop Per Child. There was virtually no international aid for that project, the money came from the countries that used the program. After that project, he worked on an initiative where they dropped off computers to children (in Ethiopia and ?) with no instruction. Within days, the children had figured it out and within six months they hacked Android. He now wants to connect 100M people (on the African continent?). He predicts that in 30 years, we will ingest information (swallow a pill where the information travels through the bloodstream and on into the brain).

For some reason, they thought it would be amusing to play the Joe Canadian commercial. Chris Hadfield is then introduced. Here’s his TED biography,

Tweeting (and covering Bowie) from the International Space Station last year, Colonel Chris Hadfield reminded the world how much we love space.

Hadfield (who has a guitar on stage with him) talks about danger (asks the audience what’s the most dangerous thing theyu’ve done) and notes that space travel is dangerous. He then  describes in detail what it’s like to get into a space shuttle and head for the space. He says that a space shuttle is the most complicated machine (?) ever built. He next shows a shuttle launch and  describes being on the International Space Station. You see a sunrise every 25 minutes due to the speed at which you are travelling. He describes his first space walk when his left eye went blind. His left eye teared up while he continued work outside the station.

In space your tears don’t fall, they build up until there’s enough force to push them across the bridge of your nose and land like a small waterfall in your right eye. When the tears wooshed over to his right eye, he became completely blind.

Hadfield asks the audience again about danger and talks about overcoming fear and dealing with real danger as opposed to perceived danger. One of the ways astronauts deal with their fear and danger is to practice until they’ve changed their primal fear.

Hadfield plays a guitar and covers David Bowie’s Space Oddity and ends his talk with these words “Fear Not.”

I am done for today and I hope there aren’t too many mistakes in this post.

TED 2014 ‘pre’ opening with prosthetics made better by 3D printing, interdisciplinary network, an app for vision testing and the Internet of Things made open

Here’s today’s (March 17, 2014) second session and a list of the fellows along with a link to their TED 2014 biography (list and links from the TED 2014 schedule),

Somi Kakoma Vocalist + Composer + Culturist
Steve Boyes conservation biologist
David Sengeh biomechatronics engineer
Eric Berlow Ecologist
Uldus Bakhtiozina photographer + visual artist
Laurel Braitman science historian + writer
Eman Mohammed Photojournalist
Andrew Bastawrous eye surgeon + innovator
Kathryn Hunt Paleopathologist
Ayah Bdeir Engineer and artist
Will Potter Investigative journalist
Kitra Cahana Vagabond photojournalist + conceptual artist
Shih Chieh Huang Artist

David Moinina Sengeh, from the MIT (Massachusetts Institute of Technology) Media Lab, focuses on biomechatronics and, more specifically, prosthetics. He was born and raised (till age 12?) in Sierra Leone where a civil war raged from 1991 to January 2002 when the war was declared finished. One of the legacies from the war has been war amputees resulting in a need for prosthetics and Sengher’s commitment to creating better prosthetics.

Even in wealthy parts of the world, an amputee may experience great discomfort from wearing a prosthetic that despite a number of fittings and adjustments never feels right and causes blisters and sores. In countries with fewer resources, getting a prosthetic that fits well is even more unlikely.

Sengeh has worked out a new way to create prosthetics that fit better and feel better, using magnetic resonance imaging (MRI) to scan the residual limb more accurately, followed by a finite-element analysis, then utilizing computer-aided design to create a  multilayer 3-D printed variable-resistance socket. One of Sengeh’s test subjects described his prosthetic socket as feeling like ‘pillows’. (You can read more about Sengeh and his work at MIT in a Dec. 18, 2012 MIT article by David L. Chandler.)  Sengeh has also founded a program in Sierra Leone to encourage and foster home-grown innovation and solutions in situations where resources are limited.

Andrew Bastawrous, Research Fellow in International Eye Health at the London School of Hygiene and Tropical Medicine, talked about his work in Kenya where he has developed an app for vision testing and diagnosis with an inexpensive device which can be clipped onto a smartphone. He demonstrated the app, Peek Vision, during his presentation.

The whole thing reminded me of Aravind, another project designed to save sight, but this one was created in India, from the Aravind Wikipedia entry (Note: Links have been removed),

Aravind Eye Care Hospital is an ophthalmological hospital with several locations in India. It was founded by Dr. Govindappa Venkataswamy in 1976. Since then it has grown into a network of eye hospitals that have seen a total of nearly 32 million patients in 36 years and performed nearly 4 million eye surgeries, the majority of them being very cheap or free. The model of Aravind Eye Care hospitals has been applauded all over the world and has become a subject for numerous case studies.[1] [2][3]

My last fellow description for this session features Ayah Bdeir and the Internet of Things.  Bdeir has developed a modular approach to creating your own electronics and, today (March 17, 2014) she was introducing a new module, the Cloud Module which would allow you to create your own internet of things. (Last week I covered a webinar with Tim O’Reilly and Jim Stogdil in a March 13, 2014 posting where they discussed big data, the Internet of Things, maker culture and other components of an upcoming Solid Conference. OReilly & Stogdil discussed two options for the Internet of Things, a proprietary approach or an open  approach.) Bdeir’s modules facilitate an open approach. Bdeir will be speaking at the Solid Conference,

Ayah Bdeir is the founder and CEO of littleBits, an award-winning library of electronics dubbed “LEGOs for the iPad generation.” Bdeir is an engineer, interactive artist, and one of the leaders of the open source hardware movement. Bdeir’s career and education have centered on advancing open source hardware to make education and innovation more accessible to people around the world.

You can find out more about littleBits and the Cloud Module here.

Transition metal dichalcogenides (molybdenum disulfide and tungsten diselenide) rock the graphene boat

Anyone who’s read stories about scientific discovery knows that the early stages are characterized by a number of possibilities so the current race to unseat graphene as the wonder material of the nanoworld is a ‘business as usual’ sign although I imagine it can be confusing for investors and others hoping to make their fortunes. As for the contenders to the ‘wonder nanomaterial throne’, they are transition metal dichalcogenides: molybdenum disulfide and tungsten diselenide both of which have garnered some recent attention.

A March 12, 2014 news item on Nanwerk features research on molybdenum disulfide from Poland,

Will one-atom-thick layers of molybdenum disulfide, a compound that occurs naturally in rocks, prove to be better than graphene for electronic applications? There are many signs that might prove to be the case. But physicists from the Faculty of Physics at the University of Warsaw have shown that the nature of the phenomena occurring in layered materials are still ill-understood and require further research.

….

Researchers at the University of Warsaw, Faculty of Physics (FUW) have shown that the phenomena occurring in the crystal network of molybdenum disulfide sheets are of a slightly different nature than previously thought. A report describing the discovery, achieved in collaboration with Laboratoire National des Champs Magnétiques Intenses in Grenoble, has recently been published in Applied Physics Letters.

“It will not become possible to construct complex electronic systems consisting of individual atomic sheets until we have a sufficiently good understanding of the physics involved in the phenomena occurring within the crystal network of those materials. Our research shows, however, that research still has a long way to go in this field”, says Prof. Adam Babinski at the UW Faculty of Physics.

A March 12, 2014 Dept. of Physics University of Warsaw (FUW) news release, which originated the news item, describes the researchers’ ideas about graphene and alternative materials such as molybdenum disulfide,

“It will not become possible to construct complex electronic systems consisting of individual atomic sheets until we have a sufficiently good understanding of the physics involved in the phenomena occurring within the crystal network of those materials. Our research shows, however, that research still has a long way to go in this field”, says Prof. Adam Babiński at the UW Faculty of Physics.

The simplest method of creating graphene is called exfoliation: a piece of scotch tape is first stuck to a piece of graphite, then peeled off. Among the particles that remain stuck to the tape, one can find microscopic layers of graphene. This is because graphite consists of many graphene sheets adjacent to one another. The carbon atoms within each layer are very strongly bound to one another (by covalent bonds, to which graphene owes its legendary resilience), but the individual layers are held together by significantly weaker bonds (van de Walls [van der Waals] bonds). Ordinary scotch tape is strong enough to break the latter and to tear individual graphene sheets away from the graphite crystal.

A few years ago it was noticed that just as graphene can be obtained from graphite, sheets a single atom thick can similarly be obtained from many other crystals. This has been successfully done, for instance, with transition metals chalcogenides (sulfides, selenides, and tellurides). Layers of molybdenum disulfide (MoS2), in particular, have proven to be a very interesting material. This compound exists in nature as molybdenite, a crystal material found in rocks around the world, frequently taking the characteristic form of silver-colored hexagonal plates. For years molybdenite has been used in the manufacturing of lubricants and metal alloys. Like in the case of graphite, the properties of single-atom sheets of MoS2 long went unnoticed.

From the standpoint of applications in electronics, molybdenum disulfide sheets exhibit a significant advantage over graphene: they have an energy gap, an energy range within which no electron states can exist. By applying electric field, the material can be switched between a state that conducts electricity and one that behaves like an insulator. By current calculations, a switched-off molybdenum disulfide transistor would consume even as little as several hundred thousand times less energy than a silicon transistor. Graphene, on the other hand, has no energy gap and transistors made of graphene cannot be fully switched off.

The news release goes on to describe how the researchers refined their understanding of molybdenum disulfide and its properties,

Valuable information about a crystal’s structure and phenomena occurring within it can be obtained by analyzing how light gets scattered within the material. Photons of a given energy are usually absorbed by the atoms and molecules of the material, then reemitted at the same energy. In the spectrum of the scattered light one can then see a distinctive peak, corresponding to that energy. It turns out, however, that one out of many millions of photons is able to use some of its energy otherwise, for instance to alter the vibration or circulation of a molecule. The reverse situation also sometimes occurs: a photon may take away some of the energy of a molecule, and so its own energy slightly increases. In this situation, known as Raman scattering, two smaller peaks are observed to either side of the main peak.

The scientists at the UW Faculty of Physics analyzed the Raman spectra of molybdenum disulfide carrying on low-temperature microscopic measurements. The higher sensitivity of the equipment and detailed analysis methods enabled the team to propose a more precise model of the phenomena occurring in the crystal network of molybdenum disulfide.

“In the case of single-layer materials, the shape of the Raman lines has previously been explained in terms of phenomena involving certain characteristic vibrations of the crystal network. We have shown for molybdenum disulfide sheets that the effects ascribed to those vibrations must actually, at least in part, be due to other network vibrations not previously taken into account”, explains Katarzyna Gołasa, a doctorate student at the UW Faculty of Physics.

The presence of the new type of vibration in single-sheet materials has an impact on how electrons behave. As a consequence, these materials must have somewhat different electronic properties than previously anticipated.

Here’s what the rocks look like,

Molybdenum disulfide occurs in nature as molybdenite, crystalline material that frequently takes the characteristic form of silver-colored hexagonal plates. (Source: FUW)

Molybdenum disulfide occurs in nature as molybdenite, crystalline material that frequently takes the characteristic form of silver-colored hexagonal plates. (Source: FUW)

I am not able to find the published research at this time (March 13, 2014).

The tungsten diselenide story is specifically application-centric. Dexter Johnson in a March 11, 2014 post on his Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website) describes the differing perspectives and potential applications suggested by the three teams that cooperated to produce papers united by a joint theme ,

The three research groups focused on optoelectronics applications of tungsten diselenide, but each with a slightly different emphasis.

The University of Washington scientists highlighted applications of the material for a light emitting diode (LED). The Vienna University of Technology group focused on the material’s photovoltaic applications. And, finally, the MIT [Massachusetts Institute of Technology] group looked at all of the optoelectronic applications for the material that would result from the way it can be switched from being a p-type to a n-type semiconductor.

Here are some details of the research from each of the institutions’ news releases.

A March 10, 2014 University of Washington (state) news release highlights their LED work,

University of Washington [UW] scientists have built the thinnest-known LED that can be used as a source of light energy in electronics. The LED is based off of two-dimensional, flexible semiconductors, making it possible to stack or use in much smaller and more diverse applications than current technology allows.

“We are able to make the thinnest-possible LEDs, only three atoms thick yet mechanically strong. Such thin and foldable LEDs are critical for future portable and integrated electronic devices,” said Xiaodong Xu, a UW assistant professor in materials science and engineering and in physics.

The UW’s LED is made from flat sheets of the molecular semiconductor known as tungsten diselenide, a member of a group of two-dimensional materials that have been recently identified as the thinnest-known semiconductors. Researchers use regular adhesive tape to extract a single sheet of this material from thick, layered pieces in a method inspired by the 2010 Nobel Prize in Physics awarded to the University of Manchester for isolating one-atom-thick flakes of carbon, called graphene, from a piece of graphite.

In addition to light-emitting applications, this technology could open doors for using light as interconnects to run nano-scale computer chips instead of standard devices that operate off the movement of electrons, or electricity. The latter process creates a lot of heat and wastes power, whereas sending light through a chip to achieve the same purpose would be highly efficient.

“A promising solution is to replace the electrical interconnect with optical ones, which will maintain the high bandwidth but consume less energy,” Xu said. “Our work makes it possible to make highly integrated and energy-efficient devices in areas such as lighting, optical communication and nano lasers.”

Here’s a link to and a citation for this team’s paper,

Electrically tunable excitonic light-emitting diodes based on monolayer WSe2 p–n junctions by Jason S. Ross, Philip Klement, Aaron M. Jones, Nirmal J. Ghimire, Jiaqiang Yan, D. G. Mandrus, Takashi Taniguchi, Kenji Watanabe, Kenji Kitamura, Wang Yao, David H. Cobden, & Xiaodong Xu. Nature Nanotechnology (2014) doi:10.1038/nnano.2014.26 Published online 09 March 2014

This paper is behind a paywall.

A March 9, 2014 University of Vienna news release highlights their work on tungsten diselinide and its possible application in solar cells,

… With graphene as a light detector, optical signals can be transformed into electric pulses on extremely short timescales.

For one very similar application, however, graphene is not well suited for building solar cells. “The electronic states in graphene are not very practical for creating photovoltaics”, says Thomas Mueller. Therefore, he and his team started to look for other materials, which, similarly to graphene, can arranged in ultrathin layers, but have even better electronic properties.

The material of choice was tungsten diselenide: It consists of one layer of tungsten atoms, which are connected by selenium atoms above and below the tungsten plane. The material absorbs light, much like graphene, but in tungsten diselenide, this light can be used to create electrical power.

The layer is so thin that 95% of the light just passes through – but a tenth of the remaining five percent, which are absorbed by the material, are converted into electrical power. Therefore, the internal efficiency is quite high. A larger portion of the incident light can be used if several of the ultrathin layers are stacked on top of each other – but sometimes the high transparency can be a useful side effect. “We are envisioning solar cell layers on glass facades, which let part of the light into the building while at the same time creating electricity”, says Thomas Mueller.

Today, standard solar cells are mostly made of silicon, they are rather bulky and inflexible. Organic materials are also used for opto-electronic applications, but they age rather quickly. “A big advantage of two-dimensional structures of single atomic layers is their crystallinity. Crystal structures lend stability”, says Thomas Mueller.

Here’s a link to and a citation for the University of Vienna paper,

Solar-energy conversion and light emission in an atomic monolayer p–n diode by Andreas Pospischil, Marco M. Furchi, & Thomas Mueller. Nature Nanotechnology (2014) doi:10.1038/nnano.2014.14 Published online 09 March 2014

This paper is behind a paywll.

Finally, a March 10, 2014 MIT news release details their work about material able to switch from p-type (p = positive) to a n-type (n = negative) semiconductors,

The material they used, called tungsten diselenide (WSe2), is part of a class of single-molecule-thick materials under investigation for possible use in new optoelectronic devices — ones that can manipulate the interactions of light and electricity. In these experiments, the MIT researchers were able to use the material to produce diodes, the basic building block of modern electronics.

Typically, diodes (which allow electrons to flow in only one direction) are made by “doping,” which is a process of injecting other atoms into the crystal structure of a host material. By using different materials for this irreversible process, it is possible to make either of the two basic kinds of semiconducting materials, p-type or n-type.

But with the new material, either p-type or n-type functions can be obtained just by bringing the vanishingly thin film into very close proximity with an adjacent metal electrode, and tuning the voltage in this electrode from positive to negative. That means the material can easily and instantly be switched from one type to the other, which is rarely the case with conventional semiconductors.

In their experiments, the MIT team produced a device with a sheet of WSe2 material that was electrically doped half n-type and half p-type, creating a working diode that has properties “very close to the ideal,” Jarillo-Herrero says.

By making diodes, it is possible to produce all three basic optoelectronic devices — photodetectors, photovoltaic cells, and LEDs; the MIT team has demonstrated all three, Jarillo-Herrero says. While these are proof-of-concept devices, and not designed for scaling up, the successful demonstration could point the way toward a wide range of potential uses, he says.

“It’s known how to make very large-area materials” of this type, Churchill says. While further work will be required, he says, “there’s no reason you wouldn’t be able to do it on an industrial scale.”

In principle, Jarillo-Herrero says, because this material can be engineered to produce different values of a key property called bandgap, it should be possible to make LEDs that produce any color — something that is difficult to do with conventional materials. And because the material is so thin, transparent, and lightweight, devices such as solar cells or displays could potentially be built into building or vehicle windows, or even incorporated into clothing, he says.

While selenium is not as abundant as silicon or other promising materials for electronics, the thinness of these sheets is a big advantage, Churchill points out: “It’s thousands or tens of thousands of times thinner” than conventional diode materials, “so you’d use thousands of times less material” to make devices of a given size.

Here’s a link to and a citation for the MIT paper,

Optoelectronic devices based on electrically tunable p–n diodes in a monolayer dichalcogenide by Britton W. H. Baugher, Hugh O. H. Churchill, Yafang Yang, & Pablo Jarillo-Herrero. Nature Nanotechnology (2014) doi:10.1038/nnano.2014.25 Published online 09 March 2014

This paper is behind a paywall.

These are very exciting, if not to say, electrifying times. (Couldn’t resist the wordplay.)

Water desalination by graphene and water purification by sapwood

I have two items about water. The first concerns a new technique from MIT (Massachusetts Institute of Technology) for desalination using graphene. From a Feb. 25, 2014 news release by David Chandler on EurekAlert,

Researchers have devised a way of making tiny holes of controllable size in sheets of graphene, a development that could lead to ultrathin filters for improved desalination or water purification.

The team of researchers at MIT, Oak Ridge National Laboratory, and in Saudi Arabia succeeded in creating subnanoscale pores in a sheet of the one-atom-thick material, which is one of the strongest materials known. …

The concept of using graphene, perforated by nanoscale pores, as a filter in desalination has been proposed and analyzed by other MIT researchers. The new work, led by graduate student Sean O’Hern and associate professor of mechanical engineering Rohit Karnik, is the first step toward actual production of such a graphene filter.

Making these minuscule holes in graphene — a hexagonal array of carbon atoms, like atomic-scale chicken wire — occurs in a two-stage process. First, the graphene is bombarded with gallium ions, which disrupt the carbon bonds. Then, the graphene is etched with an oxidizing solution that reacts strongly with the disrupted bonds — producing a hole at each spot where the gallium ions struck. By controlling how long the graphene sheet is left in the oxidizing solution, the MIT researchers can control the average size of the pores.

A big limitation in existing nanofiltration and reverse-osmosis desalination plants, which use filters to separate salt from seawater, is their low permeability: Water flows very slowly through them. The graphene filters, being much thinner, yet very strong, can sustain a much higher flow. “We’ve developed the first membrane that consists of a high density of subnanometer-scale pores in an atomically thin, single sheet of graphene,” O’Hern says.

For efficient desalination, a membrane must demonstrate “a high rejection rate of salt, yet a high flow rate of water,” he adds. One way of doing that is decreasing the membrane’s thickness, but this quickly renders conventional polymer-based membranes too weak to sustain the water pressure, or too ineffective at rejecting salt, he explains.

With graphene membranes, it becomes simply a matter of controlling the size of the pores, making them “larger than water molecules, but smaller than everything else,” O’Hern says — whether salt, impurities, or particular kinds of biochemical molecules.

The permeability of such graphene filters, according to computer simulations, could be 50 times greater than that of conventional membranes, as demonstrated earlier by a team of MIT researchers led by graduate student David Cohen-Tanugi of the Department of Materials Science and Engineering. But producing such filters with controlled pore sizes has remained a challenge. The new work, O’Hern says, demonstrates a method for actually producing such material with dense concentrations of nanometer-scale holes over large areas.

“We bombard the graphene with gallium ions at high energy,” O’Hern says. “That creates defects in the graphene structure, and these defects are more chemically reactive.” When the material is bathed in a reactive oxidant solution, the oxidant “preferentially attacks the defects,” and etches away many holes of roughly similar size. O’Hern and his co-authors were able to produce a membrane with 5 trillion pores per square centimeter, well suited to use for filtration. “To better understand how small and dense these graphene pores are, if our graphene membrane were to be magnified about a million times, the pores would be less than 1 millimeter in size, spaced about 4 millimeters apart, and span over 38 square miles, an area roughly half the size of Boston,” O’Hern says.

With this technique, the researchers were able to control the filtration properties of a single, centimeter-sized sheet of graphene: Without etching, no salt flowed through the defects formed by gallium ions. With just a little etching, the membranes started allowing positive salt ions to flow through. With further etching, the membranes allowed both positive and negative salt ions to flow through, but blocked the flow of larger organic molecules. With even more etching, the pores were large enough to allow everything to go through.

Scaling up the process to produce useful sheets of the permeable graphene, while maintaining control over the pore sizes, will require further research, O’Hern says.

Karnik says that such membranes, depending on their pore size, could find various applications. Desalination and nanofiltration may be the most demanding, since the membranes required for these plants would be very large. But for other purposes, such as selective filtration of molecules — for example, removal of unreacted reagents from DNA — even the very small filters produced so far might be useful.

“For biofiltration, size or cost are not as critical,” Karnik says. “For those applications, the current scale is suitable.”

Dexter Johnson in a Feb. 26,2014 posting provides some context for and insight into the work (from the Nanoclast blog on the IEEE [Institute of Electrical and Electronics Engineers]), Note: Links have been removed,

About 18 months ago, I wrote about an MIT project in which computer models demonstrated that graphene could act as a filter in the desalination of water through the reverse osmosis (RO) method. RO is slightly less energy intensive than the predominantly used multi-stage-flash process. The hope was that the nanopores of the graphene material would make the RO method even less energy intensive than current versions by making it easier to push the water through the filter membrane.

The models were promising, but other researchers in the field said at the time it was going to be a long road to translate a computer model to a real product.

It would seem that the MIT researchers agreed it was worth the effort and accepted the challenge to go from computer model to a real device as they announced this week that they had developed a method for creating selective pores in graphene that make it suitable for water desalination.

Here’s a link to and a citation for the paper,

Selective Ionic Transport through Tunable Subnanometer Pores in Single-Layer Graphene Membranes by Sean C. O’Hern, Michael S. H. Boutilier, Juan-Carlos Idrobo, Yi Song, Jing Kong, Tahar Laoui, Muataz Atieh, and Rohit Karnik. Nano Lett., Article ASAP DOI: 10.1021/nl404118f Publication Date (Web): February 3, 2014

Copyright © 2014 American Chemical Society

This article is behind a paywall.

The second item is also from MIT and concerns a low-tech means of purifying water. From a Feb. 27, 2014 news item on Azonano,

If you’ve run out of drinking water during a lakeside camping trip, there’s a simple solution: Break off a branch from the nearest pine tree, peel away the bark, and slowly pour lake water through the stick. The improvised filter should trap any bacteria, producing fresh, uncontaminated water.

In fact, an MIT team has discovered that this low-tech filtration system can produce up to four liters of drinking water a day — enough to quench the thirst of a typical person.

In a paper published this week in the journal PLoS ONE, the researchers demonstrate that a small piece of sapwood can filter out more than 99 percent of the bacteria E. coli from water. They say the size of the pores in sapwood — which contains xylem tissue evolved to transport sap up the length of a tree — also allows water through while blocking most types of bacteria.

Co-author Rohit Karnik, an associate professor of mechanical engineering at MIT, says sapwood is a promising, low-cost, and efficient material for water filtration, particularly for rural communities where more advanced filtration systems are not readily accessible.

“Today’s filtration membranes have nanoscale pores that are not something you can manufacture in a garage very easily,” Karnik says. “The idea here is that we don’t need to fabricate a membrane, because it’s easily available. You can just take a piece of wood and make a filter out of it.”

The Feb. 26, 2014 news release on EurekAlert, which originated the news item, describes current filtration techniques and the advantages associated with this new low-tech approach,

There are a number of water-purification technologies on the market today, although many come with drawbacks: Systems that rely on chlorine treatment work well at large scales, but are expensive. Boiling water to remove contaminants requires a great deal of fuel to heat the water. Membrane-based filters, while able to remove microbes, are expensive, require a pump, and can become easily clogged.

Sapwood may offer a low-cost, small-scale alternative. The wood is comprised of xylem, porous tissue that conducts sap from a tree’s roots to its crown through a system of vessels and pores. Each vessel wall is pockmarked with tiny pores called pit membranes, through which sap can essentially hopscotch, flowing from one vessel to another as it feeds structures along a tree’s length. The pores also limit cavitation, a process by which air bubbles can grow and spread in xylem, eventually killing a tree. The xylem’s tiny pores can trap bubbles, preventing them from spreading in the wood.

“Plants have had to figure out how to filter out bubbles but allow easy flow of sap,” Karnik observes. “It’s the same problem with water filtration where we want to filter out microbes but maintain a high flow rate. So it’s a nice coincidence that the problems are similar.”

The news release also describes the experimental procedure the scientists followed (from the news release),

To study sapwood’s water-filtering potential, the researchers collected branches of white pine and stripped off the outer bark. They cut small sections of sapwood measuring about an inch long and half an inch wide, and mounted each in plastic tubing, sealed with epoxy and secured with clamps.

Before experimenting with contaminated water, the group used water mixed with red ink particles ranging from 70 to 500 nanometers in size. After all the liquid passed through, the researchers sliced the sapwood in half lengthwise, and observed that much of the red dye was contained within the very top layers of the wood, while the filtrate, or filtered water, was clear. This experiment showed that sapwood is naturally able to filter out particles bigger than about 70 nanometers.

However, in another experiment, the team found that sapwood was unable to separate out 20-nanometer particles from water, suggesting that there is a limit to the size of particles coniferous sapwood can filter.

Finally, the team flowed inactivated, E. coli-contaminated water through the wood filter. When they examined the xylem under a fluorescent microscope, they saw that bacteria had accumulated around pit membranes in the first few millimeters of the wood. Counting the bacterial cells in the filtered water, the researchers found that the sapwood was able to filter out more than 99 percent of E. coli from water.

Karnik says sapwood likely can filter most types of bacteria, the smallest of which measure about 200 nanometers. However, the filter probably cannot trap most viruses, which are much smaller in size.

The researchers have future plans (from the news release),

Karnik says his group now plans to evaluate the filtering potential of other types of sapwood. In general, flowering trees have smaller pores than coniferous trees, suggesting that they may be able to filter out even smaller particles. However, vessels in flowering trees tend to be much longer, which may be less practical for designing a compact water filter.

Designers interested in using sapwood as a filtering material will also have to find ways to keep the wood damp, or to dry it while retaining the xylem function. In other experiments with dried sapwood, Karnik found that water either did not flow through well, or flowed through cracks, but did not filter out contaminants.

“There’s huge variation between plants,” Karnik says. “There could be much better plants out there that are suitable for this process. Ideally, a filter would be a thin slice of wood you could use for a few days, then throw it away and replace at almost no cost. It’s orders of magnitude cheaper than the high-end membranes on the market today.”

Here’s a link to and a citation for the paper,

Water Filtration Using Plant Xylem by Michael S. H. Boutilier, Jongho Lee, Valerie Chambers, Varsha Venkatesh, & Rohit Karnik. PLOS One Published: February 26, 2014 DOI: 10.1371/journal.pone.0089934

This paper is open access.

One final observation, two of the researchers listed as authors on the graphene/water desalination paper are also listed on the low-tech sapwood paper (Michael S. H. Boutilier & Rohit Karnik).

Smart suits for US soldiers—an update of sorts from the Lawrence Livermore National Laboratory

The US military has funded a program named: ‘Dynamic Multifunctional Material for a Second Skin Program’ through its Defense Threat Reduction Agency’s (DTRA) Chemical and Biological Technologies Department and Sharon Gaudin’s Feb. 20,  2014 article for Computer World offers a bit of an update on this project,which was first reported in 2012,

A U.S. soldier is on patrol with his squad when he kneels to check something out, unknowingly putting his knee into a puddle of contaminants.

The soldier isn’t harmed, though, because he or she is wearing a smart suit that immediately senses the threat and transforms the material covering his knee into a protective state that repels the potential deadly bacteria.

Scientists at the Lawrence Livermore National Laboratory, a federal government research facility in Livermore, Calif., are using nanotechnology to create clothing designed to protect U.S. soldiers from chemical and biological attacks.

“The threat is nanoscale so we need to work in the nano realm, which helps to keep it light and breathable,” said Francesco Fornasiero, a staff scientist at the lab. “If you have a nano-size threat, you need a nano-sized defense.”

Fornasiero said the task is a difficult one, and the suits may not be ready for the field for another 10 to 20 years. [emphasis mine]

One option is to use carbon nanotubes in a layer of the suit’s fabric. Sweat and air would be able to easily move through the nanotubes. However, the diameter of the nanotubes is smaller than the diameter of bacteria and viruses. That means they would not be able to pass through the tubes and reach the person wearing the suit.

However, chemicals that might be used in a chemical attack are small enough to fit through the nanotubes. To block them, researchers are adding a layer of polymer threads that extend up from the top of the nanotubes, like stalks of grass coming up from the ground.

The threads are designed to recognize the presence of chemical agents. When that happens, they swell and collapse on top of the nanotubes, blocking anything from entering them.

A second option that the Lawrence Livermore scientists are working on involves similar carbon nanotubes but with catalytic components in a polymer mesh that sits on top of the nanotubes. The components would destroy any chemical agents they come in contact with. After the chemicals are destroyed, they are shed off, enabling the suit to handle multiple attacks.

An October 6, 2012 (NR-12-10-06) Lawrence Livermore National Laboratory (LLNL) news release details the -project and the proponents,

Lawrence Livermore National Laboratory scientists and collaborators are developing a new military uniform material that repels chemical and biological agents using a novel carbon nanotube fabric.

The material will be designed to undergo a rapid transition from a breathable state to a protective state. The highly breathable membranes would have pores made of a few-nanometer-wide vertically aligned carbon nanotubes that are surface modified with a chemical warfare agent-responsive functional layer. Response to the threat would be triggered by direct chemical warfare agent attack to the membrane surface, at which time the fabric would switch to a protective state by closing the CNT pore entrance or by shedding the contaminated surface layer.

High breathability is a critical requirement for protective clothing to prevent heat-stress and exhaustion when military personnel are engaged in missions in contaminated environments. Current protective military uniforms are based on heavyweight full-barrier protection or permeable adsorptive protective overgarments that cannot meet the critical demand of simultaneous high comfort and protection, and provide a passive rather than active response to an environmental threat.

To provide high breathability, the new composite material will take advantage of the unique transport properties of carbon nanotube pores, which have two orders of magnitude faster gas transport rates when compared with any other pore of similar size.

“We have demonstrated that our small-size prototype carbon nanotube membranes can provide outstanding breathability in spite of the very small pore sizes and porosity,” said Sangil Kim, another LLNL scientist in the Biosciences and Biotechnology Division. “With our collaborators, we will develop large area functionalized CNT membranes.”

Biological agents, such as bacteria or viruses, are close to 10 nanometers in size. Because the membrane pores on the uniform are only a few nanometers wide, these membranes will easily block biological agents.

However, chemical agents are much smaller in size and require the membrane pores to be able to react to block the threat. To create a multifunctional membrane, the team will surface modify the original prototype carbon nanotube membranes with chemical threat responsive functional groups. The functional groups on the membrane will sense and block the threat like gatekeepers on entrance. A second response scheme also will be developed: Similar to how a living skin peels off when challenged with dangerous external factors, the fabric will exfoliate upon reaction with the chemical agent. In this way, the fabric will be able to block chemical agents such as sulfur mustard (blister agent), GD and VX nerve agents, toxins such as staphylococcal enterotoxin and biological spores such as anthrax.

The project is funded for $13 million over five years with LLNL as the lead institution. The Livermore team is made up of Fornasiero [Francesco Fornasiero], Kim and Kuang Jen Wu. Other collaborators and institutions involved in the project include Timothy Swager at Massachusetts Institute of Technology, Jerry Shan at Rutgers University, Ken Carter, James Watkins, and Jeffrey Morse at the University of Massachusetts-Amherst, Heidi Schreuder-Gibson at Natick Soldier Research Development and Engineering Center, and Robert Praino at Chasm Technologies Inc.

“Development of chemical threat responsive carbon nanotube membranes is a great example of novel material’s potential to provide innovative solutions for the Department of Defense CB needs,” said Tracee Harris, the DTRA science and technology manager for the Dynamic Multifunctional Material for a Second Skin Program. “This futuristic uniform would allow our military forces to operate safely for extended time periods and successfully complete their missions in environments contaminated with chemical and biological warfare agents.”

The Laboratory has a history in developing carbon nanotubes for a wide range of applications including desalination. “We have an advanced carbon nanotube platform to build and expand to make advancements in the protective fabric material for this new project,” Wu said.

The new uniforms could be deployed in the field in less than 10 years. [emphasis mine]

Since Gaudin’s 2014 article quotes one of the LLNL’s scientists, Francesco Fornasiero, with an estimate for the suit’s deployment into the field as 10 – 20 years as opposed to the “less than 10 years” estimated in the news release, I’m guessing the problem has proved more complex than was first anticipated.

For anyone who’s interested in more details about  US soldiers and nanotechnology,

  • May 1, 2013 article by Max Cacas for Signal Online provides more details about the overall Smart Skin programme and its goals.
  • Nov. 15, 2013 article by Kris Walker for Azonano.com describes the Smart Skin project along with others including the intriguingly titled: ‘Warrior Web’.
  • website for MIT’s (Massachusetts Institute of Technology) Institute for Soldier Nanotechnologies Note: The MIT researcher mentioned in the LLNL news release is a faculty member of the Institute for Soldier Nanotechnologies.
  • website for the Defense Threat Reduction Agency

A wearable book (The Girl Who Was Plugged In) makes you feel the protagonists pain

A team of students taking an MIT (Massachusetts Institute of Technology) course called ‘Science Fiction to Science Fabrication‘ have created a new kind of category for books, sensory fiction.  John Brownlee in his Feb. 10, 2014 article for Fast Company describes it this way,

Have you ever felt your pulse quicken when you read a book, or your skin go clammy during a horror story? A new student project out of MIT wants to deepen those sensations. They have created a wearable book that uses inexpensive technology and neuroscientific hacking to create a sort of cyberpunk Neverending Story that blurs the line between the bodies of a reader and protagonist.

Called Sensory Fiction, the project was created by a team of four MIT students–Felix Heibeck, Alexis Hope, Julie Legault, and Sophia Brueckner …

Here’s the MIT video demonstrating the book in use (from the course’s sensory fiction page),

Here’s how the students have described their sensory book, from the project page,

Sensory fiction is about new ways of experiencing and creating stories.

Traditionally, fiction creates and induces emotions and empathy through words and images.  By using a combination of networked sensors and actuators, the Sensory Fiction author is provided with new means of conveying plot, mood, and emotion while still allowing space for the reader’s imagination. These tools can be wielded to create an immersive storytelling experience tailored to the reader.

To explore this idea, we created a connected book and wearable. The ‘augmented’ book portrays the scenery and sets the mood, and the wearable allows the reader to experience the protagonist’s physiological emotions.

The book cover animates to reflect the book’s changing atmosphere, while certain passages trigger vibration patterns.

Changes in the protagonist’s emotional or physical state triggers discrete feedback in the wearable, whether by changing the heartbeat rate, creating constriction through air pressure bags, or causing localized temperature fluctuations.

Our prototype story, ‘The Girl Who Was Plugged In’ by James Tiptree showcases an incredible range of settings and emotions. The main protagonist experiences both deep love and ultimate despair, the freedom of Barcelona sunshine and the captivity of a dark damp cellar.

The book and wearable support the following outputs:

  • Light (the book cover has 150 programmable LEDs to create ambient light based on changing setting and mood)
  • Sound
  • Personal heating device to change skin temperature (through a Peltier junction secured at the collarbone)
  • Vibration to influence heart rate
  • Compression system (to convey tightness or loosening through pressurized airbags)

One of the earliest stories about this project was a Jan. 28,2014 piece written by Alison Flood for the Guardian where she explains how vibration, etc. are used to convey/stimulate the reader’s sensations and emotions,

MIT scientists have created a ‘wearable’ book using temperature and lighting to mimic the experiences of a book’s protagonist

The book, explain the researchers, senses the page a reader is on, and changes ambient lighting and vibrations to “match the mood”. A series of straps form a vest which contains a “heartbeat and shiver simulator”, a body compression system, temperature controls and sound.

“Changes in the protagonist’s emotional or physical state trigger discrete feedback in the wearable [vest], whether by changing the heartbeat rate, creating constriction through air pressure bags, or causing localised temperature fluctuations,” say the academics.

Flood goes on to illuminate how science fiction has explored the notion of ‘sensory books’ (Note: Links have been removed) and how at least one science fiction novelist is responding to this new type of book,,

The Arthur C Clarke award-winning science fiction novelist Chris Beckett wrote about a similar invention in his novel Marcher, although his “sensory” experience comes in the form of a video game:

Adam Roberts, another prize-winning science fiction writer, found the idea of “sensory” fiction “amazing”, but also “infantalising, like reverting to those sorts of books we buy for toddlers that have buttons in them to generate relevant sound-effects”.

Elise Hu in her Feb. 6, 2014 posting on the US National Public Radio (NPR) blog, All Tech Considered, takes a different approach to the topic,

The prototype does work, but it won’t be manufactured anytime soon. The creation was only “meant to provoke discussion,” Hope says. It was put together as part of a class in which designers read science fiction and make functional prototypes to explore the ideas in the books.

If it ever does become more widely available, sensory fiction could have an unintended consequence. When I shared this idea with NPR editor Ellen McDonnell, she quipped, “If these device things are helping ‘put you there,’ it just means the writing won’t have to be as good.”

I hope the students are successful at provoking discussion as so far they seem to have primarily provoked interest.

As for my two cents, I think that in a world where it seems making personal connections  is increasingly difficult (i.e., people becoming more isolated) that sensory fiction which stimulates people into feeling something as they read a book seems a logical progression.  It’s also interesting to me that all of the focus is on the reader with no mention as to what writers might produce (other than McDonnell’s cheeky comment) if they knew their books were going to be given the ‘sensory treatment’. One more musing, I wonder if there might a difference in how males and females, writers and readers, respond to sensory fiction.

Now for a bit of wordplay. Feeling can be emotional but, in English, it can also refer to touch and researchers at MIT have also been investigating new touch-oriented media.  You can read more about that project in my Reaching beyond the screen with the Tangible Media Group at the Massachusetts Institute of Technology (MIT) posting dated Nov. 13, 2013. One final thought, I am intrigued by how interested scientists at MIT seem to be in feelings of all kinds.

A millionth of a trillionth of a gram: attoscale weight

Researchers at the Massachusetts Institute of Technology (MIT) have found a means of measuring particle weight, with increased accuracy, at the attoscale according to a Jan. 13, 2014 news item on ScienceDaily,

MIT engineers have devised a way to measure the mass of particles with a resolution better than an attogram — one millionth of a trillionth of a gram. Weighing these tiny particles, including both synthetic nanoparticles and biological components of cells, could help researchers better understand their composition and function.

The Jan. 13, 2014 MIT news release by Anne Trafton (also on EurekAlert), which originated the news item, describes the origins of the technology that the researchers adapted to achieve increased resolution,

The system builds on a technology previously developed by Scott Manalis, an MIT professor of biological and mechanical engineering, to weigh larger particles, such as cells. This system, known as a suspended microchannel resonator (SMR), measures the particles’ mass as they flow through a narrow channel.

By shrinking the size of the entire system, the researchers were able to boost its resolution to 0.85 attograms —more than a 30-fold improvement over the previous generation of the device.

“Now we can weigh small viruses, extracellular vesicles, and most of the engineered nanoparticles that are being used for nanomedicine,” says Selim Olcum, a postdoc in Manalis’ lab  …

Manalis first developed the SMR system in 2007 to measure the mass of living cells, as well as particles as small as a femtogram (one quadrillionth of a gram, or 1,000 attograms). Since then, his lab has used the device to track cell growth over time, measure cell density, and measure other physical properties, such as stiffness.

The original mass sensor consists of a fluid-filled microchannel etched in a tiny silicon cantilever that vibrates inside a vacuum cavity. As cells or particles flow through the channel, one at a time, their mass slightly alters the cantilever’s vibration frequency. The mass of the particle can be calculated from that change in frequency.

To make the device sensitive to smaller masses, the researchers had to shrink the size of the cantilever, which behaves much like a diving board, Olcum says. When a diver bounces at the end of a diving board, it vibrates with a very large amplitude and low frequency. When the diver plunges into the water, the board begins to vibrate much faster because the total mass of the board has dropped considerably.

To measure smaller masses, a smaller “diving board” is required. “If you’re measuring nanoparticles with a large cantilever, it’s like having a huge diving board with a tiny fly on it. When the fly jumps off, you don’t notice any difference. That’s why we had to make very tiny diving boards,” Olcum says.

In a previous study, researchers in Manalis’ lab built a 50-micron cantilever — about one-tenth the size of the cantilever used for measuring cells. That system, known as a suspended nanochannel resonator (SNR), was able to weigh particles as light as 77 attograms at a rate of a particle or two per second.

Here’s how the scientists accomplished their latest goal of getting more precise measurements of weight (from the news release),

The cantilever in the new version of the SNR device is 22.5 microns long, and the channel that runs across it is 1 micron wide and 400 nanometers deep. This miniaturization makes the system more sensitive because it increases the cantilever’s vibration frequency. At higher frequencies, the cantilever is more responsive to smaller changes in mass.

The researchers got another boost in resolution by switching the source for the cantilever’s vibration from an electrostatic to a piezoelectric excitation, which produces a larger amplitude and, in turn, decreases the impact of spurious vibrations that interfere with the signal they are trying to measure.

With this system, the researchers can measure nearly 30,000 particles in a little more than 90 minutes. “In the span of a second, we’ve got four or five particles going through, and we could potentially increase the concentration and have particles going through faster,” Cermak says.

To demonstrate the device’s usefulness in analyzing engineered nanoparticles, the MIT team weighed nanoparticles made of DNA bound to tiny gold spheres, which allowed them to determine how many gold spheres were bound to each DNA-origami scaffold. That information can be used to assess yield, which is important for developing precise nanostructures, such as scaffolds for nanodevices.

The researchers also tested the SNR system on biological nanoparticles called exosomes — vesicles that carry proteins, RNA, or other molecules secreted by cells — which are believed to play a role in signaling between distant locations in the body.

They found that exosomes secreted by liver cells and fibroblasts (cells that make up connective tissue) had different profiles of mass distribution, suggesting that it may be possible to distinguish vesicles that originate from different cells and may have different biological functions.

The researchers are now investigating using the SNR device to detect exosomes in the blood of patients with glioblastoma (GBM), a type of brain cancer. This type of tumor secretes large quantities of exosomes, and tracking changes in their concentration could help doctors monitor patients as they are treated.

Glioblastoma exosomes can now be detected by mixing blood samples with magnetic nanoparticles coated with antibodies that bind to markers found on vesicle surfaces, but the SNR could provide a simpler test.

Here’s a link to and a citation for the researchers’ abstract,

Weighing nanoparticles in solution at the attogram scale by Selim Olcuma, Nathan Cermak, Steven C. Wasserman, Kathleen S. Christine, Hiroshi Atsumi, Kris R. Payer, Wenjiang Shen, Jungchul Lee, Angela M. Belcher, Sangeeta N. Bhatia, and Scott R. Manalis. Proceedings of the National Academy of Sciences of the United States of America (PNAS), doi: 10.1073/pnas.1318602111 Published online Jan. 13, 2014

This article is behind a paywall.