Tag Archives: origami

Growing electronics on trees

An April 26, 2022 news item on phys.org caught my eye with its mention of nanocellulose, trees, and electronics,

Electronics can grow on trees thanks to nanocellulose paper semiconductors

Semiconducting nanomaterials with 3D network structures have high surface areas and a lot of pores that make them excellent for applications involving adsorbing, separating, and sensing. However, simultaneously controlling the electrical properties and creating useful micro- and macro-scale structures, while achieving excellent functionality and end-use versatility, remains challenging. Now, Osaka University researchers, in collaboration with The University of Tokyo, Kyushu University, and Okayama University, have developed a nanocellulose paper semiconductor that provides both nano−micro−macro trans-scale designability of the 3D structures and wide tunability of the electrical properties. Their findings are published in ACS Nano.

Cellulose is a natural and easy to source material derived from wood. Cellulose nanofibers (nanocellulose) can be made into sheets of flexible nanocellulose paper (nanopaper) with dimensions like those of standard A4. Nanopaper does not conduct an electric current; however, heating can introduce conducting properties. Unfortunately, this exposure to heat can also disrupt the nanostructure.

The researchers have therefore devised a treatment process that allows them to heat the nanopaper without damaging the structures of the paper from the nanoscale up to the macroscale.

Caption: Schematic diagram of the preparation of the wood nanocellulose-derived nano-semiconductor with customizable electrical properties and 3D structures Credit: 2022 Koga et al. Nanocellulose paper semiconductor with a 3D network structure and its nano−micro−macro trans-scale design. ACS Nano

An April 28, 2022 Osaka University news release (also on EurekAlert), which originated the news item, provides more detail about the work

“An important property for the nanopaper semiconductor is tunability because this allows devices to be designed for specific applications,” explains study author Hirotaka Koga. “We applied an iodine treatment that was very effective for protecting the nanostructure of the nanopaper. Combining this with spatially controlled drying meant that the pyrolysis treatment did not substantially alter the designed structures and the selected temperature could be used to control the electrical properties.”

The researchers used origami (paper folding) and kirigami (paper cutting) techniques to provide playful examples of the flexibility of the nanopaper at the macrolevel. A bird and box were folded, shapes including an apple and snowflake were punched out, and more intricate structures were produced by laser cutting. This demonstrated the level of detail possible, as well as the lack of damage caused by the heat treatment.

Examples of successful applications showed nanopaper semiconductor sensors incorporated into wearable devices to detect exhaled moisture breaking through facemasks and moisture on the skin. The nanopaper semiconductor was also used as an electrode in a glucose biofuel cell and the energy generated lit a small bulb.

“The structure maintenance and tunability that we have been able to show is very encouraging for the translation of nanomaterials into practical devices,” says Associate Professor Koga. “We believe that our approach will underpin the next steps in sustainable electronics made entirely from plant materials.”

About Osaka University

Osaka University was founded in 1931 as one of the seven imperial universities of Japan and is now one of Japan’s leading comprehensive universities with a broad disciplinary spectrum. This strength is coupled with a singular drive for innovation that extends throughout the scientific process, from fundamental research to the creation of applied technology with positive economic impacts. Its commitment to innovation has been recognized in Japan and around the world, being named Japan’s most innovative university in 2015 (Reuters 2015 Top 100) and one of the most innovative institutions in the world in 2017 (Innovative Universities and the Nature Index Innovation 2017). Now, Osaka University is leveraging its role as a Designated National University Corporation selected by the Ministry of Education, Culture, Sports, Science and Technology to contribute to innovation for human welfare, sustainable development of society, and social transformation.

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

Nanocellulose Paper Semiconductor with a 3D Network Structure and Its Nano–Micro–Macro Trans-Scale Design by Hirotaka Koga, Kazuki Nagashima, Koichi Suematsu, Tsunaki Takahashi, Luting Zhu, Daiki Fukushima, Yintong Huang, Ryo Nakagawa, Jiangyang Liu, Kojiro Uetani, Masaya Nogi, Takeshi Yanagida, and Yuta Nishina. ACS Nano 2022, XXXX, XXX, XXX-XXX DOI: https://doi.org/10.1021/acsnano.1c10728 Publication Date:April 26, 2022 © 2022 The Authors. Published by American Chemical Society

The paper appears to be open access.

An exoskeleton for a cell-sized robot

A January 3, 2018 news item on phys.org announces work on cell-sized robots,

An electricity-conducting, environment-sensing, shape-changing machine the size of a human cell? Is that even possible?

Cornell physicists Paul McEuen and Itai Cohen not only say yes, but they’ve actually built the “muscle” for one.

With postdoctoral researcher Marc Miskin at the helm, the team has made a robot exoskeleton that can rapidly change its shape upon sensing chemical or thermal changes in its environment. And, they claim, these microscale machines – equipped with electronic, photonic and chemical payloads – could become a powerful platform for robotics at the size scale of biological microorganisms.

“You could put the computational power of the spaceship Voyager onto an object the size of a cell,” Cohen said. “Then, where do you go explore?”

“We are trying to build what you might call an ‘exoskeleton’ for electronics,” said McEuen, the John A. Newman Professor of Physical Science and director of the Kavli Institute at Cornell for Nanoscale Science. “Right now, you can make little computer chips that do a lot of information-processing … but they don’t know how to move or cause something to bend.”

Cornell University has produced a video of the researchers discussing their work (about 3 mins. running time)

For those who prefer text or need it to reinforce their understanding, there’s a January 2, 2018 Cornell University news release (also on EurekAlert but dated Jan. 3, 2018) by Tom Fleischman, which originated the news item,

The machines move using a motor called a bimorph. A bimorph is an assembly of two materials – in this case, graphene and glass – that bends when driven by a stimulus like heat, a chemical reaction or an applied voltage. The shape change happens because, in the case of heat, two materials with different thermal responses expand by different amounts over the same temperature change.

As a consequence, the bimorph bends to relieve some of this strain, allowing one layer to stretch out longer than the other. By adding rigid flat panels that cannot be bent by bimorphs, the researchers localize bending to take place only in specific places, creating folds. With this concept, they are able to make a variety of folding structures ranging from tetrahedra (triangular pyramids) to cubes.

In the case of graphene and glass, the bimorphs also fold in response to chemical stimuli by driving large ions into the glass, causing it to expand. Typically this chemical activity only occurs on the very outer edge of glass when submerged in water or some other ionic fluid. Since their bimorph is only a few nanometers thick, the glass is basically all outer edge and very reactive.

“It’s a neat trick,” Miskin said, “because it’s something you can do only with these nanoscale systems.”

The bimorph is built using atomic layer deposition – chemically “painting” atomically thin layers of silicon dioxide onto aluminum over a cover slip – then wet-transferring a single atomic layer of graphene on top of the stack. The result is the thinnest bimorph ever made. One of their machines was described as being “three times larger than a red blood cell and three times smaller than a large neuron” when folded. Folding scaffolds of this size have been built before, but this group’s version has one clear advantage.

“Our devices are compatible with semiconductor manufacturing,” Cohen said. “That’s what’s making this compatible with our future vision for robotics at this scale.”

And due to graphene’s relative strength, Miskin said, it can handle the types of loads necessary for electronics applications. “If you want to build this electronics exoskeleton,” he said, “you need it to be able to produce enough force to carry the electronics. Ours does that.”

For now, these tiniest of tiny machines have no commercial application in electronics, biological sensing or anything else. But the research pushes the science of nanoscale robots forward, McEuen said.

“Right now, there are no ‘muscles’ for small-scale machines,” he said, “so we’re building the small-scale muscles.”

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

Graphene-based bimorphs for micron-sized, autonomous origami machines by Marc Z. Miskin, Kyle J. Dorsey, Baris Bircan, Yimo Han, David A. Muller, Paul L. McEuen, and Itai Cohen. PNAS [Proceedings of the National Academy of Sciences] 2018 doi: 10.1073/pnas.1712889115 published ahead of print January 2, 2018

This paper is behind a paywall.

‘Origami organs’ for tissue engineering

This is a different approach to tissue engineering and its the consequence of a serendipitous accident.  From an Aug. 7, 2017 Northwestern University news release (also on EurekAlert),

Northwestern Medicine scientists and engineers have invented a range of bioactive “tissue papers” made of materials derived from organs that are thin and flexible enough to even fold into an origami bird. The new biomaterials can potentially be used to support natural hormone production in young cancer patients and aid wound healing.

The tissue papers are made from structural proteins excreted by cells that give organs their form and structure. The proteins are combined with a polymer to make the material pliable.

In the study, individual types of tissue papers were made from ovarian, uterine, kidney, liver, muscle or heart proteins obtained by processing pig and cow organs. Each tissue paper had specific cellular properties of the organ from which it was made.

The article describing the tissue paper and its function will be published Aug. 7 in the journal Advanced Functional Materials.

“This new class of biomaterials has potential for tissue engineering and regenerative medicine as well as drug discovery and therapeutics,” corresponding author Ramille Shah said. “It’s versatile and surgically friendly.”

Shah is an assistant professor of surgery at the Feinberg School of Medicine and an assistant professor of materials science and engineering at McCormick School of Engineering. She also is a member of the Simpson Querrey Institute for BioNanotechnology.

For wound healing, Shah thinks the tissue paper could provide support and the cell signaling needed to help regenerate tissue to prevent scarring and accelerate healing.

The tissue papers are made from natural organs or tissues. The cells are removed, leaving the natural structural proteins – known as the extracellular matrix – that then are dried into a powder and processed into the tissue papers. Each type of paper contains residual biochemicals and protein architecture from its original organ that can stimulate cells to behave in a certain way.

In the lab of reproductive scientist Teresa Woodruff, the tissue paper made from a bovine ovary was used to grow ovarian follicles when they were cultured in vitro. The follicles (eggs and hormone-producing cells) grown on the tissue paper produced hormones necessary for proper function and maturation.

“This could provide another option to restore normal hormone function to young cancer patients who often lose their hormone function as a result of chemotherapy and radiation,” Woodruff, a study coauthor, said.

A strip of the ovarian paper with the follicles could be implanted under the arm to restore hormone production for cancer patients or even women in menopause.

Woodruff is the director of the Oncofertility Consortium and the Thomas J. Watkins Memorial Professor of Obstetrics and Gynecology at Feinberg.

In addition, the tissue paper made from various organs separately supported the growth of adult human stem cells. Scientists placed human bone marrow stem cells on the tissue paper, and all the stem cells attached and multiplied over four weeks.

“That’s a good sign that the paper supports human stem cell growth,” said first author Adam Jakus, who developed the tissue papers. “It’s an indicator that once we start using tissue paper in animal models it will be biocompatible.”

The tissue papers feel and behave much like standard office paper when they are dry, Jakus said. Jakus simply stacks them in a refrigerator or a freezer. He even playfully folded them into an origami bird.

“Even when wet, the tissue papers maintain their mechanical properties and can be rolled, folded, cut and sutured to tissue,” he said.

Jakus was a Hartwell postdoctoral fellow in Shah’s lab for the study and is now chief technology officer and cofounder of the startup company Dimension Inx, LLC, which was also cofounded by Shah. The company will develop, produce and sell 3-D printable materials primarily for medical applications. The Intellectual Property is owned by Northwestern University and will be licensed to Dimension Inx.

An Accidental Spill Sparked Invention

An accidental spill of 3-D printing ink in Shah’s lab by Jakus sparked the invention of the tissue paper. Jakus was attempting to make a 3-D printable ovary ink similar to the other 3-D printable materials he previously developed to repair and regenerate bone, muscle and nerve tissue. When he went to wipe up the spill, the ovary ink had already formed a dry sheet.

“When I tried to pick it up, it felt strong,” Jakus said. “I knew right then I could make large amounts of bioactive materials from other organs. The light bulb went on in my head. I could do this with other organs.”

“It is really amazing that meat and animal by-products like a kidney, liver, heart and uterus can be transformed into paper-like biomaterials that can potentially regenerate and restore function to tissues and organs,” Jakus said. “I’ll never look at a steak or pork tenderloin the same way again.”

For those who like their news in a video,

As someone who once made baklava, that does not look like filo pastry, where an individual sheet is quite thin and rips easily. Enough said.

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

“Tissue Papers” from Organ-Specific Decellularized Extracellular Matrices by Adam E. Jakus, Monica M. Laronda, Alexandra S. Rashedi, Christina M. Robinson, Chris Lee, Sumanas W. Jordan, Kyle E. Orwig, Teresa K. Woodruff, and Ramille N. Shah. Advnaced Functional Materials DOI: 10.1002/adfm.201700992 Version of Record online: 7 AUG 2017

© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

DNA-based nanowires in your computer?

In the quest for smaller and smaller, DNA (deoxyribonucleic acid) is being exploited as never before. From a Nov. 9, 2016 news item on phys.org,

Tinier than the AIDS virus—that is currently the circumference of the smallest transistors. The industry has shrunk the central elements of their computer chips to fourteen nanometers in the last sixty years. Conventional methods, however, are hitting physical boundaries. Researchers around the world are looking for alternatives. One method could be the self-organization of complex components from molecules and atoms. Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and Paderborn University have now made an important advance: the physicists conducted a current through gold-plated nanowires, which independently assembled themselves from single DNA strands. …

A Nov. 9, 2016 HZDR press release (also on EurekAlert), which originated the news item, provides more information,

At first glance, it resembles wormy lines in front of a black background. But what the electron microscope shows up close is that the nanometer-sized structures connect two electrical contacts. Dr. Artur Erbe from the Institute of Ion Beam Physics and Materials Research is pleased about what he sees. “Our measurements have shown that an electrical current is conducted through these tiny wires.” This is not necessarily self-evident, the physicist stresses. We are, after all, dealing with components made of modified DNA. In order to produce the nanowires, the researchers combined a long single strand of genetic material with shorter DNA segments through the base pairs to form a stable double strand. Using this method, the structures independently take on the desired form.

“With the help of this approach, which resembles the Japanese paper folding technique origami and is therefore referred to as DNA-origami, we can create tiny patterns,” explains the HZDR researcher. “Extremely small circuits made of molecules and atoms are also conceivable here.” This strategy, which scientists call the “bottom-up” method, aims to turn conventional production of electronic components on its head. “The industry has thus far been using what is known as the ‘top-down’ method. Large portions are cut away from the base material until the desired structure is achieved. Soon this will no longer be possible due to continual miniaturization.” The new approach is instead oriented on nature: molecules that develop complex structures through self-assembling processes.

Golden Bridges Between Electrodes

The elements that thereby develop would be substantially smaller than today’s tiniest computer chip components. Smaller circuits could theoretically be produced with less effort. There is, however, a problem: “Genetic matter doesn’t conduct a current particularly well,” points out Erbe. He and his colleagues have therefore placed gold-plated nanoparticles on the DNA wires using chemical bonds. Using a “top-down” method – electron beam lithography — they subsequently make contact with the individual wires electronically. “This connection between the substantially larger electrodes and the individual DNA structures have come up against technical difficulties until now. By combining the two methods, we can resolve this issue. We could thus very precisely determine the charge transport through individual wires for the first time,” adds Erbe.

As the tests of the Dresden researchers have shown, a current is actually conducted through the gold-plated wires — it is, however, dependent on the ambient temperature. “The charge transport is simultaneously reduced as the temperature decreases,” describes Erbe. “At normal room temperature, the wires function well, even if the electrons must partially jump from one gold particle to the next because they haven’t completely melded together. The distance, however, is so small that it currently doesn’t even show up using the most advanced microscopes.” In order to improve the conduction, Artur Erbe’s team aims to incorporate conductive polymers between the gold particles. The physicist believes the metallization process could also still be improved.

He is, however, generally pleased with the results: “We could demonstrate that the gold-plated DNA wires conduct energy. We are actually still in the basic research phase, which is why we are using gold rather than a more cost-efficient metal. We have, nevertheless, made an important stride, which could make electronic devices based on DNA possible in the future.”

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

Temperature-Dependent Charge Transport through Individually Contacted DNA Origami-Based Au Nanowires by Bezu Teschome, Stefan Facsko, Tommy Schönherr, Jochen Kerbusch, Adrian Keller, and Artur Erbe. Langmuir, 2016, 32 (40), pp 10159–10165, DOI: 10.1021/acs.langmuir.6b01961, Publication Date (Web): September 14, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.

Not origami but kirigami-inspired foldable batteries

Origami is not noted for its stretchy qualities, a shortcoming according to a June 16, 2015 news item on Azonano,

Origami, the centuries-old Japanese paper-folding art, has inspired recent designs for flexible energy-storage technology. But energy-storage device architecture based on origami patterns has so far been able to yield batteries that can change only from simple folded to unfolded positions. They can flex, but not actually stretch.

Now an Arizona State University [ASU] research team has overcome the limitation by using a variation of origami, called kirigami, as a design template for batteries that can be stretched to more than 150 percent of their original size and still maintain full functionality.

A June 15, 2015 ASU news release, which originated the news item, provides a few more details about the kirigami-influenced batteries (Note: A link has been removed),

A paper published on June 11 [2015] in the research journal Scientific Reports describes how the team developed kirigami-based lithium-ion batteries using a combination of folds and cuts to create patterns that enable a significant increase in stretchability.

The kirigami-based prototype battery was sewn into an elastic wristband that was attached to a smart watch. The battery fully powered the watch and its functions – including playing video – as the band was being stretched.

“This type of battery could potentially be used to replace the bulky and rigid batteries that are limiting the development of compact wearable electronic devices,” Jiang said.

Such stretchable batteries could even be integrated into fabrics – including those used for clothing, he said.

The researchers have provided a video demonstrating the kirigami-inspired battery in action,

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

Kirigami-based stretchable lithium-ion batteries by Zeming Song, Xu Wang, Cheng Lv, Yonghao An, Mengbing Liang, Teng Ma, David He, Ying-Jie Zheng, Shi-Qing Huang, Hongyu Yu & Hanqing Jiang. Scientific Reports 5, Article number: 10988 doi:10.1038/srep10988 Published 11 June 2015

This is an open access paper.

According to the ASU news release, the team published a previous paper on origami-inspired batteries and some of the problems associated with them (Note: Links have been removed),

An earlier paper in the research journal Nature Communications by Jiang and some of his research team members and other colleagues provides an in-depth look at progress and obstacles in the development of origami-based lithium-ion batteries.

The paper explains technical challenges in flexible-battery development that Jiang says his team’s kirigami-based devices are helping to solve.

Read more about the team’s recent progress and the potential applications of stretchable batteries in Popular Mechanics, the Christian Science Monitor, Yahoo News and the Daily Mail.

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

Origami lithium-ion batteries by Zeming Song, Teng Ma,    Rui Tang, Qian Cheng, Xu Wang, Deepakshyam Krishnaraju, Rahul Panat, Candace K. Chan, Hongyu Yu, & Hanqing Jiang. Nature Communications 5, Article number: 3140 doi:10.1038/ncomms4140 Published 28 January 2014

This paper is behind a paywall but there is a free preview available via ReadCube Access.

On a related note, Dexter Johnson has written up Binghamton University research into paper-based origami batteries powered by the respiration of bacteria in a June 16, 2015 posting on his Nanoclast blog.

A new artform: folded lithium-ion batteries made of paper coated with carbon nanotubes

The above image illustrates the architecture of a foldable lithium-ion battery ASU engineers have constructed using paper coated with carbon nanotubes. They began with a porous, lint-free paper towel, coated it with polyvinylidene difluoride to improve adhesion of carbon nanotubes and then immersed the paper into a solution of carbon nanotubes. Powders of lithium titanate oxide and lithium cobalt oxide — standard lithium battery electrodes — are sandwiched between two sheets of the paper. Thin foils of copper and aluminum are placed above and below the sheets of paper to complete the battery.. Courtesy: Arizona State University

The above image illustrates the architecture of a foldable lithium-ion battery ASU engineers have constructed using paper coated with carbon nanotubes. They began with a porous, lint-free paper towel, coated it with polyvinylidene difluoride to improve adhesion of carbon nanotubes and then immersed the paper into a solution of carbon nanotubes. Powders of lithium titanate oxide and lithium cobalt oxide — standard lithium battery electrodes — are sandwiched between two sheets of the paper. Thin foils of copper and aluminum are placed above and below the sheets of paper to complete the battery.. Courtesy: Arizona State University

Despite the fact that I’m wondering about what happened to A (in the illustration), here’s the Oct. 22, 2013 Arizona State University news release by Joe Kullman (h/t Azonano) which describes the ‘origami’ breakthrough,

Arizona State University engineers have constructed a lithium-ion battery using paper coated with carbon nanotubes that provide electrical conductivity.

Using an origami-folding pattern similar to how maps are folded, they folded the paper into a stack of 25 layers, producing a compact, flexible battery that provides significant energy density —  or the amount of energy stored in a given system or space per unit of volume of mass.

Their research paper in the journal Nano Letters has drawn attention from websites that focus on news of technological breakthroughs.

The researchers have also developed a new process to incorporate a polymer binder onto the carbon nanotube-coated paper. The polymer binder improves adhesion of the structure’s active materials.

The achievements open up possibilities of using the origami technique to create new forms of paper-based energy storage devices, including batteries, light-emitting diodes, circuits and transistors, says Candace Chan, who led the research team.

Here’s a link to and a citation for article in Nano Letters,

Folding Paper-Based Lithium-Ion Batteries for Higher Areal Energy Densities by Qian Cheng, Zeming Song, Teng Ma, Bethany B. Smith, Rui Tang, Hongyu Yu, Hanqing Jiang, and Candace K. Chan. Nano Lett., 2013, 13 (10), pp 4969–4974 DOI: 10.1021/nl4030374 Publication Date (Web): September 23, 2013
Copyright © 2013 American Chemical Society

This article is behind a paywall.

Buildable, bendable, and biological; a kirigami-based project at Cornell University

A May 18, 2013 news item on Azonano highlights a new project at Cornell University,

Cornell researchers Jenny Sabin, assistant professor of architecture, and Dan Luo, professor of biological and environmental engineering, are among the lead investigators on a new research project to produce “buildable, bendable and biological materials” for a wide range of applications.

The project is intended to bring new ideas, motifs, portability and design to the formation of intricate chemical, biological and architectural materials.

Based on Kirigami (from the Japanese word kiru, “to cut”), the project “offers a previously unattainable level of design, dynamics and deployability” to self-folding and unfolding materials from the molecular scale to the architectural level, according to the researchers.

The May 16, 2013 Cornell University news release by Daniel Aloi, which originated the news item, describes the project’s intent,

The project is intended to illuminate new principles of architecture, materials synthesis and biological structures, and advance several technologies – including meta-materials, sensors, stealth aircraft and adaptive and sustainable buildings. A complementary goal is to generate public interest through an enhanced impact on science, art and engineering.

“Like the opening and closing of flowers, satellites and even greeting cards, our research will offer a rich and diverse set of intricate surprises, problems and challenges for students at all levels, and broaden their interest and awareness of emerging science and engineering,” according to the project proposal, “Cutting and Pasting: Kirigami in Architecture, Technology and Science” (KATS).

The Emerging Frontiers in Research Innovation grant from the NSF is in the research category of Origami Design for Integration of Self-assembling Systems for Engineering Innovation.

I wish they had a few sample illustrations of how this project might look as a macroscale architectural (or other type of) project even it is a complete fantasy.

Folding, origami, and shapeshifting and an article with over 50,000 authors

I’m on a metaphor kick these days so here goes, origami (Japanese paper folding), and shapeshifting are metaphors used to describe a certain biological process that nanoscientists from fields not necessarily associated with biology find fascinating, protein folding.

Origami

Take for example a research team at the California Institute of Technology (Caltech) working to exploit the electronic properties of carbon nanotubes (mentioned in a Nov. 9, 2010 news item on Nanowerk). One of the big issues is that since all of the tubes in a sample are made of carbon getting one tube to react on its own without activating the others is quite challenging when you’re trying to create nanoelectronic circuits. The research team decided to use a technique developed in a bioengineering lab (from the news item),

DNA origami is a type of self-assembled structure made from DNA that can be programmed to form nearly limitless shapes and patterns (such as smiley faces or maps of the Western Hemisphere or even electrical diagrams). Exploiting the sequence-recognition properties of DNA base paring, DNA origami are created from a long single strand of viral DNA and a mixture of different short synthetic DNA strands that bind to and “staple” the viral DNA into the desired shape, typically about 100 nanometers (nm) on a side.

Single-wall carbon nanotubes are molecular tubes composed of rolled-up hexagonal mesh of carbon atoms. With diameters measuring less than 2 nm and yet with lengths of many microns, they have a reputation as some of the strongest, most heat-conductive, and most electronically interesting materials that are known. For years, researchers have been trying to harness their unique properties in nanoscale devices, but precisely arranging them into desirable geometric patterns has been a major stumbling block.

… To integrate the carbon nanotubes into this system, the scientists colored some of those pixels anti-red, and others anti-blue, effectively marking the positions where they wanted the color-matched nanotubes to stick. They then designed the origami so that the red-labeled nanotubes would cross perpendicular to the blue nanotubes, making what is known as a field-effect transistor (FET), one of the most basic devices for building semiconductor circuits.

Although their process is conceptually simple, the researchers had to work out many kinks, such as separating the bundles of carbon nanotubes into individual molecules and attaching the single-stranded DNA; finding the right protection for these DNA strands so they remained able to recognize their partners on the origami; and finding the right chemical conditions for self-assembly.

After about a year, the team had successfully placed crossed nanotubes on the origami; they were able to see the crossing via atomic force microscopy. These systems were removed from solution and placed on a surface, after which leads were attached to measure the device’s electrical properties. When the team’s simple device was wired up to electrodes, it indeed behaved like a field-effect transistor

Shapeshifting

For another more recent example (from an August 5, 2010 article on physorg.com by Larry Hardesty,  Shape-shifting robots),

By combining origami and electrical engineering, researchers at MIT and Harvard are working to develop the ultimate reconfigurable robot — one that can turn into absolutely anything. The researchers have developed algorithms that, given a three-dimensional shape, can determine how to reproduce it by folding a sheet of semi-rigid material with a distinctive pattern of flexible creases. To test out their theories, they built a prototype that can automatically assume the shape of either an origami boat or a paper airplane when it receives different electrical signals. The researchers reported their results in the July 13 issue of the Proceedings of the National Academy of Sciences.

As director of the Distributed Robotics Laboratory at the Computer Science and Artificial Intelligence Laboratory (CSAIL), Professor Daniela Rus researches systems of robots that can work together to tackle complicated tasks. One of the big research areas in distributed robotics is what’s called “programmable matter,” the idea that small, uniform robots could snap together like intelligent Legos to create larger, more versatile robots.

Here’s a video from this site at MIT (Massachusetts Institute of Technology) describing the process,

Folding and over 50, 000 authors

With all this I’ve been leading up to a fascinating project, a game called Foldit, that a team from the University of Washington has published results from in the journal Nature (Predicting protein structures with a multiplayer online game), Aug. 5, 2010.

With over 50,000 authors, this study is a really good example of citizen science (discussed in my May 14, 2010 posting and elsewhere here) and how to use games to solve science problems while exploiting a fascination with folding and origami. From the Aug. 5, 2010 news item on Nanowerk,

The game, Foldit, turns one of the hardest problems in molecular biology into a game a bit reminiscent of Tetris. Thousands of people have now played a game that asks them to fold a protein rather than stack colored blocks or rescue a princess.

Scientists know the pieces that make up a protein but cannot predict how those parts fit together into a 3-D structure. And since proteins act like locks and keys, the structure is crucial.

At any moment, thousands of computers are working away at calculating how physical forces would cause a protein to fold. But no computer in the world is big enough, and computers may not take the smartest approach. So the UW team tried to make it into a game that people could play and compete. Foldit turns protein-folding into a game and awards points based on the internal energy of the 3-D protein structure, dictated by the laws of physics.

Tens of thousands of players have taken the challenge. The author list for the paper includes an acknowledgment of more than 57,000 Foldit players, which may be unprecedented on a scientific publication.

“It’s a new kind of collective intelligence, as opposed to individual intelligence, that we want to study,”Popoviç [principal investigator Zoran Popoviç, a UW associate professor of computer science and engineering] said. “We’re opening eyes in terms of how people think about human intelligence and group intelligence, and what the possibilities are when you get huge numbers of people together to solve a very hard problem.”

There’s a more at Nanowerk including a video about the gamers and the scientists. I think most of us take folding for granted and yet it stimulates all kinds of research and ideas.