Category Archives: biomimcry

A 3D spider web, a VR (virtual reality) setup, and sonification (music)

Markus Buehler and his musical spider webs are making news again.

Caption: Cross-sectional images (shown in different colors) of a spider web were combined into this 3D image and translated into music. Credit: Isabelle Su and Markus Buehler

The image (so pretty) you see in the above comes from a Markus Buehler presentation that was made at the American Chemical Society (ACS) meeting. ACS Spring 2021 being held online April 5-30, 2021. The image was also shown during a press conference which the ACS has made available for public viewing. More about that later in this posting.

The ACS issued an April 12, 2021 news release (also on EurekAlert), which provides details about Buehler’s latest work on spider webs and music,

Spiders are master builders, expertly weaving strands of silk into intricate 3D webs that serve as the spider’s home and hunting ground. If humans could enter the spider’s world, they could learn about web construction, arachnid behavior and more. Today, scientists report that they have translated the structure of a web into music, which could have applications ranging from better 3D printers to cross-species communication and otherworldly musical compositions.

The researchers will present their results today at the spring meeting of the American Chemical Society (ACS). ACS Spring 2021 is being held online April 5-30 [2021]. Live sessions will be hosted April 5-16, and on-demand and networking content will continue through April 30 [2021]. The meeting features nearly 9,000 presentations on a wide range of science topics.

“The spider lives in an environment of vibrating strings,” says Markus Buehler, Ph.D., the project’s principal investigator, who is presenting the work. “They don’t see very well, so they sense their world through vibrations, which have different frequencies.” Such vibrations occur, for example, when the spider stretches a silk strand during construction, or when the wind or a trapped fly moves the web.

Buehler, who has long been interested in music, wondered if he could extract rhythms and melodies of non-human origin from natural materials, such as spider webs. “Webs could be a new source for musical inspiration that is very different from the usual human experience,” he says. In addition, by experiencing a web through hearing as well as vision, Buehler and colleagues at the Massachusetts Institute of Technology (MIT), together with collaborator Tomás Saraceno at Studio Tomás Saraceno, hoped to gain new insights into the 3D architecture and construction of webs.

With these goals in mind, the researchers scanned a natural spider web with a laser to capture 2D cross-sections and then used computer algorithms to reconstruct the web’s 3D network. The team assigned different frequencies of sound to strands of the web, creating “notes” that they combined in patterns based on the web’s 3D structure to generate melodies. The researchers then created a harp-like instrument and played the spider web music in several live performances around the world.

The team also made a virtual reality setup that allowed people to visually and audibly “enter” the web. “The virtual reality environment is really intriguing because your ears are going to pick up structural features that you might see but not immediately recognize,” Buehler says. “By hearing it and seeing it at the same time, you can really start to understand the environment the spider lives in.”

To gain insights into how spiders build webs, the researchers scanned a web during the construction process, transforming each stage into music with different sounds. “The sounds our harp-like instrument makes change during the process, reflecting the way the spider builds the web,” Buehler says. “So, we can explore the temporal sequence of how the web is being constructed in audible form.” This step-by-step knowledge of how a spider builds a web could help in devising “spider-mimicking” 3D printers that build complex microelectronics. “The spider’s way of ‘printing’ the web is remarkable because no support material is used, as is often needed in current 3D printing methods,” he says.

In other experiments, the researchers explored how the sound of a web changes as it’s exposed to different mechanical forces, such as stretching. “In the virtual reality environment, we can begin to pull the web apart, and when we do that, the tension of the strings and the sound they produce change. At some point, the strands break, and they make a snapping sound,” Buehler says.

The team is also interested in learning how to communicate with spiders in their own language. They recorded web vibrations produced when spiders performed different activities, such as building a web, communicating with other spiders or sending courtship signals. Although the frequencies sounded similar to the human ear, a machine learning algorithm correctly classified the sounds into the different activities. “Now we’re trying to generate synthetic signals to basically speak the language of the spider,” Buehler says. “If we expose them to certain patterns of rhythms or vibrations, can we affect what they do, and can we begin to communicate with them? Those are really exciting ideas.”

You can go here for the April 12, 2021 ‘Making music from spider webs’ ACS press conference’ it runs about 30 mins. and you will hear some ‘spider music’ played.

Getting back to the image and spider webs in general, we are most familiar with orb webs (in the part of Canada where I from if nowhere else), which look like spirals and are 2D. There are several other types of webs some of which are 3D, like tangle webs, also known as cobwebs, funnel webs and more. See this March 18, 2020 article “9 Types of Spider Webs: Identification + Pictures & Spiders” by Zach David on Beyond the Treat for more about spiders and their webs. If you have the time, I recommend reading it.

I’ve been following Buehler’s spider web/music work for close to ten years now; the latest previous posting is an October 23, 2019 posting where you’ll find a link to an application that makes music from proteins (spider webs are made up of proteins; scroll down about 30% of the way; it’s in the 2nd to last line of the quoted text about the embedded video).

Here is a video (2 mins. 17 secs.) of a spider web music performance that Buehler placed on YouTube,

Feb 3, 2021

Markus J. Buehler

Spider’s Canvas/Arachonodrone show excerpt at Palais de Tokyo, Paris, on November 2018. Video by MIT CAST. More videos can be found on www.arachnodrone.com. The performance was commissioned by Studio Tomás Saraceno (STS), in the context of Saraceno’s carte blanche exhibition, ON AIR. Spider’s Canvas/Arachnodrone was performed by Isabelle Su and Ian Hattwick on the spider web instrument, Evan Ziporyn on the EWI (Electronic Wind Instrument), and Christine Southworth on the guitar and EBow (Electronic Bow)

You can find more about the spider web music and Buehler’s collaborators on http://www.arachnodrone.com/,

Spider’s Canvas / Arachnodrone is inspired by the multifaceted work of artist Tomas Saraceno, specifically his work using multiple species of spiders to make sculptural webs. Different species make very different types of webs, ranging not just in size but in design and functionality. Tomas’ own web sculptures are in essence collaborations with the spiders themselves, placing them sequentially over time in the same space, so that the complex, 3-dimensional sculptural web that results is in fact built by several spiders, working together.

Meanwhile, back among the humans at MIT, Isabelle Su, a Course 1 doctoral student in civil engineering, has been focusing on analyzing the structure of single-species spider webs, specifically the ‘tent webs’ of the cyrtophora citricola, a tropical spider of particular interest to her, Tomas, and Professor Markus Buehler. Tomas gave the department a cyrtophora spider, the department gave the spider a space (a small terrarium without glass), and she in turn built a beautiful and complex web. Isabelle then scanned it in 3D and made a virtual model. At the suggestion of Evan Ziporyn and Eran Egozy, she then ported the model into Unity, a VR/game making program, where a ‘player’ can move through it in numerous ways. Evan & Christine Southworth then worked with her on ‘sonifying’ the web and turning it into an interactive virtual instrument, effectively turning the web into a 1700-string resonating instrument, based on the proportional length of each individual piece of silk and their proximity to one another. As we move through the web (currently just with a computer trackpad, but eventually in a VR environment), we create a ‘sonic biome’: complex ‘just intonation’ chords that come in and out of earshot according to which of her strings we are closest to. That part was all done in MAX/MSP, a very flexible high level audio programming environment, which was connected with the virtual environment in Unity. Our new colleague Ian Hattwick joined the team focusing on sound design and spatialization, building an interface that allowed him the sonically ‘sculpt’ the sculpture in real time, changing amplitude, resonance, and other factors. During this performance at Palais de Tokyo, Isabelle toured the web – that’s what the viewer sees – while Ian adjusted sounds, so in essence they were together “playing the web.” Isabelle provides a space (the virtual web) and a specific location within it (by driving through), which is what the viewer sees, from multiple angles, on the 3 scrims. The location has certain acoustic potentialities, and Ian occupies them sonically, just as a real human performer does in a real acoustic space. A rough analogy might be something like wandering through a gothic cathedral or a resonant cave, using your voice or an instrument at different volumes and on different pitches to find sonorous resonances, echoes, etc. Meanwhile, Evan and Christine are improvising with the web instrument, building on Ian’s sound, with Evan on EWI (Electronic Wind Instrument) and Christine on electric guitar with EBow.

For the visuals, Southworth wanted to create the illusion that the performers were actually inside the web. We built a structure covered in sharkstooth scrim, with 3 projectors projecting in and through from 3 sides. Southworth created images using her photographs of local Lexington, MA spider webs mixed with slides of the scan of the web at MIT, and then mixed those images with the projection of the game, creating an interactive replica of Saraceno’s multi-species webs.

If you listen to the press conference, you will hear Buehler talk about practical applications for this work in materials science.

Lobster-inspired 3D printed concrete

A January 19, 2021 news item on ScienceDaily highlights bioinspired 3D printing of concrete,

New research shows that patterns inspired by lobster shells can make 3D printed concrete stronger, to support more complex and creative architectural structures.

Digital manufacturing technologies like 3D concrete printing (3DCP) have immense potential to save time, effort and material in construction.

They also promise to push the boundaries of architectural innovation, yet technical challenges remain in making 3D printed concrete strong enough for use in more free-form structures.

In a new experimental study, researchers at RMIT University [Australia] looked to the natural strength of lobster shells to design special 3D printing patterns.

Their bio-mimicking spiral patterns improved the overall durability of the 3D printed concrete, as well as enabling the strength to be precisely directed for structural support where needed.

Video: Carelle Mulawa-Richards

A January 19, 2021 RMIT University press release (also on EurekAlert) by Gosia Kaszubska, which originated the news item, goes into technical detail about the research once you get past the ‘fluffy’ bits,

When the team combined the twisting patterns with a specialised concrete mix enhanced with steel fibres, the resulting material was stronger than traditionally-made concrete.

Lead researcher Dr Jonathan Tran said 3D printing and additive manufacturing opened up opportunities in construction for boosting both efficiency and creativity.

“3D concrete printing technology has real potential to revolutionise the construction industry, and our aim is to bring that transformation closer,” said Tran, a senior lecturer in structured materials and design at RMIT.

“Our study explores how different printing patterns affect the structural integrity of 3D printed concrete, and for the first time reveals the benefits of a bio-inspired approach in 3DCP.

“We know that natural materials like lobster exoskeletons?have evolved into high-performance structures over millions of years, so by mimicking their key advantages we can follow where nature has already innovated.”

3D printing for construction

The automation of concrete construction is set to transform how we build, with construction the next frontier in the automation and data-driven revolution known as industry 4.0.

A 3D concrete printer builds houses or makes structural components by depositing the material layer-by-layer, unlike the traditional approach of casting concrete in a mould.

With the latest technology, a house can be 3D printed in just 24 hours for about half the cost, while construction on the world’s first 3D printed community began in 2019 in Mexico.

The emerging industry is already supporting architectural and engineering innovation, such as a 3D printed office building in Dubai, a nature-mimicking concrete bridge in Madrid and The Netherlands’ sail-shaped “Europe Building”.

The research team in RMIT’s School of Engineering focuses on 3D printing concrete, exploring ways to enhance the finished product through different combinations of printing pattern design, material choices, modelling, design optimisation and reinforcement options.

Patterns for printing

The most conventional pattern used in 3D printing is unidirectional, where layers are laid down on top of each other in parallel lines.

The new study published in a special issue of 3D Printing and Additive Manufacturing investigated the effect of different printing patterns on the strength of steel fibre-enhanced concrete.

Previous research by the RMIT team found that including 1-2% steel fibres in the concrete mix reduces defects and porosity, increasing strength. The fibres also help the concrete harden early without deformation, enabling higher structures to be built.

The team tested the impact of printing the concrete in helicoidal patterns (inspired by the internal structure of lobster shells), cross-ply and quasi-isotropic patterns (similar to those used for laminated composite structures and layer-by-layer deposited composites) and standard unidirectional patterns.

Supporting complex structures

The results showed strength improvement from each of the patterns, compared with unidirectional printing, but Tran said the spiral patterns hold the most promise for supporting complex 3D printed concrete structures.

“As lobster shells are naturally strong and naturally curved, we know this could help us deliver stronger concrete shapes like arches and flowing or twisted structures,” he said.

“This work is in early stages so we need further research to test how the concrete performs on a wider range of parameters, but our initial experimental results show we are on the right track.”

Further studies will be supported through a new large-scale mobile concrete 3D printer recently acquired by RMIT – making it the first research institution in the southern hemisphere to commission a machine of this kind.

The 5×5m robotic printer will be used by the team to research the 3D printing of houses, buildings and large structural components.

The team will also use the machine to explore the potential for 3D printing with concrete made with recycled waste materials such as soft plastic aggregate.

The work is connected to a new project with industry partners Replas and SR Engineering, focusing on sound-dampening walls made from post-consumer recycled soft plastics and concrete, which was recently supported with an Australian Government Innovations Connections grant.

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

Influences of Printing Pattern on Mechanical Performance of Three-Dimensional-Printed Fiber-Reinforced Concrete by Luong Pham, Guoxing Lu, and Phuong Tran. 3D Printing and Additive Manufacturing DOI: https://doi.org/10.1089/3dp.2020.0172 Published Online:30 Dec 2020

This paper is open access.

A lotus root-inspired hydrogel fiber for surgical sutures

By FotoosRobin – originally posted to Flickr as Lotus root, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=4826529

The lotus (Nelumbo nucifera) rhizome (mass of roots) is not the prettiest part of the lotus but its fibers (and presumably fiber from other parts of the lotus plant) served as inspiration for a hydrogel that might be used as a surgical suture according to a Jan. 14, 2021 news item on phys.org (Note: Links have been removed),

“The lotus roots may break, but the fiber remains joined”—an old Chinese saying that reflects the unique structure and mechanical properties of the lotus fiber. The outstanding mechanical properties of lotus fibers can be attributed to their unique spiral structure, which provides an attractive model for biomimetic design of artificial fibers.

In a new study published in Nano Letters, a team led by Prof. Yu Shuhong from the University of Science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS) reported a bio-inspired lotus-fiber-mimetic spiral structure bacterial cellulose (BC) hydrogel fiber with high strength, high toughness, excellent biocompatibility, good stretchability, and high energy dissipation.

A Jan. 14, 2021 University of Science and Technology of China press release on the Chinese Academy of Sciences website (also on EurekAlert), which originated the news item, describes the new hydrogel in more detail,

Unlike polymer-based hydrogel, the newly designed biomimetic hydrogel fiber (BHF) is based on the BC hydrogel with 3D cellulose nanofiber networks produced by bacteria. The cellulose nanofibers provide the reversible hydrogen bonding network that results in unique mechanical properties.

The researchers applied a constant tangential force to the pretreated BC hydrogel along the cross-sectional direction. Then, the two sides of the hydrogel were subjected to opposite tangential forces, and local plastic deformation occurred.

The hydrogen bonds in the 3D network of cellulose nanofibers were broken by the tangential force, causing the hydrogel strip to twist spirally and the network to slip and deform. When the tangential force was removed, the hydrogen bonds reformed between the nanofibers, and the spiral structure of the fiber was fixed.

Benefited from lotus-fiber-mimetic spiral structure, the toughness of BHF can reach ?116.3 MJ m-3, which is more than nine times higher than those of non-spiralized BC hydrogel fiber. Besides, once the BHF is stretched, it is nearly non-resilient.

Combining outstanding mechanical properties with excellent biocompatibility derived from BC, BHF is a promising hydrogel fiber for biomedical material, especially for surgical suture, a commonly used structural biomedical material for wound repair.

Compared with commercial surgical suture with higher modulus, the BHF has similar modulus and strength to soft tissue, like skin. The outstanding stretchability and energy dissipation of BHF allow it to absorb energy from the tissue deformation around a wound and effectively protect the wound from rupture, which makes BHF an ideal surgical suture.

What’s more, the porous structure of BHF also allows it to adsorb functional small molecules, such as antibiotics or anti-inflammatory compounds, and sustainably release them on wounds. With an appropriate design, BHF would be a powerful platform for many medical applications.

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

Bio-Inspired Lotus-Fiber-like Spiral Hydrogel Bacterial Cellulose Fibers by Qing-Fang Guan, Zi-Meng Han, YinBo Zhu, Wen-Long Xu, Huai-Bin Yang, Zhang-Chi Ling, Bei-Bei Yan, Kun-Peng Yang, Chong-Han Yin, HengAn Wu, and Shu-Hong Yu. Nano Lett. 2021, XXXX, XXX, XXX-XXX DOI: https://doi.org/10.1021/acs.nanolett.0c03707 Publication Date:January 5, 2021 Copyright © 2021 American Chemical Society

This paper is behind a paywall.

Mother-of-pearl self-assembles from disorder into perfection

Courtesy: Mother-of-pearl Courtesy: Technische Universitaet (TU) Dresden

Mother-of-pearl (also known as nacre) research has been featured here a few times (links at the end of this post). This time it touches on self-assembly, which is the source of much interest and, on occasion, much concern in the field of nanotechnology.

In any case, the latest mother-of-pearl work comes from the Technische Universität (TU) Dresden (Technical University of Dresden), located in Germany. From a January 4, 2021 news item on phys.org,

In a new study published in Nature Physics, researchers from the B CUBE—Center for Molecular Bioengineering at TU Dresden and European Synchrotron Radiation Facility (ESRF) in Grenoble [Grance] describe, for the first time, that structural defects in self-assembling nacre attract and cancel each other out, eventually leading to a perfect periodic structure.

A January 4, 2021 Technische Universität (TU) Dresden press release (also on EurekAlert), which originated the news item, explains the reason for the ongoing interest in mother-of-pearl and reveals an unexpected turn in the research,

Mollusks build shells to protect their soft tissues from predators. Nacre, also known as the mother of pearl, has an intricate, highly regular structure that makes it an incredibly strong material. Depending on the species, nacres can reach tens of centimeters in length. No matter the size, each nacre is built from materials deposited by a multitude of single cells at multiple different locations at the same time. How exactly this highly periodic and uniform structure emerges from the initial disorder was unknown until now.

Nacre formation starts uncoordinated with the cells depositing the material simultaneously at different locations. Not surprisingly, the early nacre structure is not very regular. At this point, it is full of defects. “In the very beginning, the layered mineral-organic tissue is full of structural faults that propagate through a number of layers like a helix. In fact, they look like a spiral staircase, having either right-handed or left-handed orientation,” says Dr. Igor Zlotnikov, research group leader at the B CUBE – Center for Molecular Bioengineering at TU Dresden. “The role of these defects in forming such a periodic tissue has never been established. On the other hand, the mature nacre is defect-free, with a regular, uniform structure. How could perfection emerge from such disorder?”

The researchers from the Zlotnikov group collaborated with the European Synchrotron Radiation Facility (ESRF) in Grenoble to take a very detailed look at the internal structure of the early and mature nacre. Using synchrotron-based holographic X-ray nano-tomography the researchers could capture the growth of nacre over time. “Nacre is an extremely fine structure, having organic features below 50 nm in size. Beamline ID16A at the ESRF provided us with an unprecedented capability to visualize nacre in three-dimensions,” explains Dr. Zlotnikov. “The combination of electron dense and highly periodical inorganic platelets with delicate and slender organic interfaces makes nacre a challenging structure to image. Cryogenic imaging helped us to obtain the resolving power we needed,” explains Dr. ‘Alexandra] Pacureanu from the X-ray Nanoprobe group at the ESRF.

The analysis of data was quite a challenge. The researchers developed a segmentation algorithm using neural networks and trained it to separate different layers of nacre. In this way, they were able to follow what happens to the structural defects as nacre grows.

The behavior of structural defects in a growing nacre was surprising. Defects of opposite screw direction were attracted to each other from vast distances. The right-handed and left-handed defects moved through the structure, until they met, and cancelled each other out. These events led to a tissue-wide synchronization. Over time, it allowed the structure to develop into a perfectly regular and defect-free.

Periodic structures similar to nacre are produced by many different animal species. The researchers think that the newly discovered mechanism could drive not only the formation of nacre but also other biogenic structures.

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

Dynamics of topological defects and structural synchronization in a forming periodic tissue by Maksim Beliaev, Dana Zöllner, Alexandra Pacureanu, Paul Zaslansky & Igor Zlotnikov. Nature Physics (2021) First published online: 17 September 2020 Published: 04 January 2021

This paper is behind a paywall.

As promised here are the links for One tough mother, imitating mother-of-pearl for stronger ceramics (a March 14, 2014 posting) and Clues as to how mother of pearl is made (a December 15, 2015 posting).

Water and minerals have a nanoscale effect on bones

Courtesy: University of Arkansas

What a great image of bones! This December 3, 2020 University of Arkansas news release (also on EurekAlert) by Matt McGowan features research focused on bone material looks exciting. The date for the second study citation and link that I have listed (at the end of this posting) suggests the more recent study may have been initially overlooked in the deluge of COVID-19 research we are experiencing,

University of Arkansas researchers Marco Fielder and Arun Nair have conducted the first study of the combined nanoscale effects of water and mineral content on the deformation mechanisms and thermal properties of collagen, the essence of bone material.

The researchers also compared the results to the same properties of non-mineralized collagen reinforced with carbon nanotubes, which have shown promise as a reinforcing material for bio-composites. This research aids in the development of synthetic materials to mimic bone.

Using molecular dynamics — in this case a computer simulation of the physical movements of atoms and molecules — Nair and Fielder examined the mechanics and thermal properties of collagen-based bio-composites containing different weight percentages of minerals, water and carbon nanotubes when subjected to external loads.

They found that variations of water and mineral content had a strong impact on the mechanical behavior and properties of the bio-composites, the structure of which mimics nanoscale bone composition. With increased hydration, the bio-composites became more vulnerable to stress. Additionally, Nair and Fielder found that the presence of carbon nanotubes in non-mineralized collagen reduced the deformation of the gap regions.

The researchers also tested stiffness, which is the standard measurement of a material’s resistance to deformation. Both mineralized and non-mineralized collagen bio-composites demonstrated less stability with greater water content. Composites with 40% mineralization were twice as strong as those without minerals, regardless of the amount of water content. Stiffness of composites with carbon nanotubes was comparable to that of the mineralized collagen.

“As the degree of mineralization or carbon nanotube content of the collagenous bio-composites increased, the effect of water to change the magnitude of deformation decreased,” Fielder said.

The bio-composites made of collagen and carbon nanotubes were also found to have a higher specific heat than the studied mineralized collagen bio-composites, making them more likely to be resistant to thermal damage that could occur during implantation or functional use of the composite. Like most biological materials, bone is a hierarchical – with different structures at different length scales. At the microscale level, bone is made of collagen fibers, composed of smaller nanofibers called fibrils, which are a composite of collagen proteins, mineralized crystals called apatite and water. Collagen fibrils overlap each other in some areas and are separated by gaps in other areas.

“Though several studies have characterized the mechanics of fibrils, the effects of variation and distribution of water and mineral content in fibril gap and overlap regions are unexplored,” said Nair, who is an associate professor of mechanical engineering. “Exploring these regions builds an understanding of the structure of bone, which is important for uncovering its material properties. If we understand these properties, we can design and build better bio-inspired materials and bio-composites.”

Here are links and citations for both papers mentioned in the news release,

Effects of hydration and mineralization on the deformation mechanisms of collagen fibrils in bone at the nanoscale by Marco Fielder & Arun K. Nair. Biomechanics and Modeling in Mechanobiology volume 18, pages57–68 (2019) Biomech Model Mechanobiol 18, 57–68 (2019). DOI: https://doi.org/10.1007/s10237-018-1067-y First published: 07 August 2018 Issue Date: 15 February 2019

This paper is behind a paywall.

A computational study of mechanical properties of collagen-based bio-composites by Marco Fielder & Arun K. Nair. International Biomechanics Volume 7, 2020 – Issue 1 Pages 76-87 DOI: https://doi.org/10.1080/23335432.2020.1812428 Published online: 02 Sep 2020

This paper is open access.

Spider web-like electronics with graphene

A spiderweb-inspired fractal design is used for hemispherical 3D photodetection to replicate the vision system of arthropods. (Sena Huh image)

This image is pretty and I’m pretty sure it’s an illustration and not a real photodetection system. Regardless, an Oct. 21, 2020 news item on Nanowerk describes the research into producing a real 3D hemispheric photodetector for biomedical imaging (Note: A link has been removed),

Purdue University innovators are taking cues from nature to develop 3D photodetectors for biomedical imaging.

The researchers used some architectural features from spider webs to develop the technology. Spider webs typically provide excellent mechanical adaptability and damage-tolerance against various mechanical loads such as storms.

“We employed the unique fractal design of a spider web for the development of deformable and reliable electronics that can seamlessly interface with any 3D curvilinear surface,” said Chi Hwan Lee, a Purdue assistant professor of biomedical engineering and mechanical engineering. “For example, we demonstrated a hemispherical, or dome-shaped, photodetector array that can detect both direction and intensity of incident light at the same time, like the vision system of arthropods such as insects and crustaceans.”

The Purdue technology uses the structural architecture of a spider web that exhibits a repeating pattern. This work is published in Advanced Materials (“Fractal Web Design of a Hemispherical Photodetector Array with Organic-Dye-Sensitized Graphene Hybrid Composites”).

An Oct. 21, 2020 Purdue University news release by Chris Adam, which originated the news item, delves further into the work,

Lee said this provides unique capabilities to distribute externally induced stress throughout the threads according to the effective ratio of spiral and radial dimensions and provides greater extensibility to better dissipate force under stretching. Lee said it also can tolerate minor cuts of the threads while maintaining overall strength and function of the entire web architecture.

“The resulting 3D optoelectronic architectures are particularly attractive for photodetection systems that require a large field of view and wide-angle antireflection, which will be useful for many biomedical and military imaging purposes,” said Muhammad Ashraful Alam, the Jai N. Gupta Professor of Electrical and Computer Engineering.

Alam said the work establishes a platform technology that can integrate a fractal web design with system-level hemispherical electronics and sensors, thereby offering several excellent mechanical adaptability and damage-tolerance against various mechanical loads.

“The assembly technique presented in this work enables deploying 2D deformable electronics in 3D architectures, which may foreshadow new opportunities to better advance the field of 3D electronic and optoelectronic devices,” Lee said.

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

Fractal Web Design of a Hemispherical Photodetector Array with Organic‐Dye‐Sensitized Graphene Hybrid Composites by Eun Kwang Lee, Ratul Kumar Baruah, Jung Woo Leem, Woohyun Park, Bong Hoon Kim, Augustine Urbas, Zahyun Ku, Young L. Kim, Muhammad Ashraful Alam, Chi Hwan Lee. Advanced Materials Volume 32, Issue 46 November 19, 2020 2004456 DOI: https://doi.org/10.1002/adma.202004456 First published online: 12 October 2020

This paper is behind a paywall.

Mystery of North American insect bioluminescent systems unraveled by Brazilian scientists

I’ve always been fond of ‘l’ words and so it is that I’m compelled to post a story about a “luciferin-luciferase system” or, in this case, a story about insect bioluminescence.

Caption: Researchers isolated molecules present in the larvae of the fungus gnat Orfelia fultoni Credit: Vadim Viviani, UFSCar

A September 9, 2020 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) press release (also on EurekAlert but published Sept. 11, 2020) announces research into ‘blue’ bioluminescence,

Molecules belonging to an almost unknown bioluminescent system found in larvae of the fungus gnat Orfelia fultoni (subfamily Keroplatinae) have been isolated for the first time by researchers at the Federal University of São Carlos (UFSCar) in the state of São Paulo, Brazil. The small fly is one of the few terrestrial organisms that produce blue light. It inhabits riverbanks in the Appalachian Mountains in the eastern United States. A key part of its bioluminescent system is a molecule also present in two recently discovered Brazilian flies.

The study, supported by Paulo Research Foundation – FAPESP, is published in Scientific Reports. Five authors are affiliated with UFSCar and two with universities in the United States.

The bioluminescent systems of glow-worms, fireflies and other insects are normally made up of luciferin (a low molecular weight molecule) and luciferase, an enzyme that catalyzes the oxidation of luciferin by oxygen, producing light. While some bioluminescent systems are well known and even used in biotechnological applications, others are poorly understood, including blue light-emitting systems, such as that of O. fultoni.

“In the published paper, we describe the properties of the insect’s luciferase and luciferin and their anatomical location in its larvae. We also specify several possible proteins that are possible candidates for the luciferase. We don’t yet know what type of protein it is, but it’s likely to be a hexamerin. In insects, hexamerins are storage proteins that provide amino acids, besides having other functions, such as binding low molecular weight compounds, like luciferin,” said Vadim Viviani, a professor in UFSCar’s Sustainability Science and Technology Center (CCTS) in Sorocaba, São Paulo, and principal investigator for the study.

The study was part of the FAPESP-funded project “Arthropod bioluminescence“. The partnership with United States-based researchers dates from a previous project, supported by FAPESP and the United States National Science Foundation (NSF), in partnership with Vanderbilt University (VU), located in Nashville, Tennessee.

In addition to luciferin and luciferase, researchers began characterizing a complex found in insects of the family Keroplatidae, which, in addition to O. fultoni, also includes a Brazilian species in the genus Neoditomyia that produces only luciferin and hence does not emit light.

Because they do not use it to emit light, the luciferin in O. fultoni and the Brazilian Neoditomyia has been named keroplatin. In larvae of this subfamily, keroplatin is associated with “black bodies” – large cells containing dark granules, proteins and probably mitochondria (energy-producing organelles). Researchers are still investigating the biological significance of this association between keroplatin and mitochondria.

“It’s a mystery,” Viviani said. “This luciferin may play a role in the mitochondrial energy metabolism. At night, probably in the presence of a natural chemical reducer, the luciferin is released by these black bodies and reacts with the surrounding luciferase to produce blue light. These are possibilities we plan to study.”

Brazilian cousins

An important factor in the elucidation of the United States insect’s bioluminescent system was the discovery of a larva that lives in Intervales State Park in São Paulo in 2018. It does not emit light but produces luciferin, similar to O. fultoni (read more at: agencia.fapesp.br/29066).

In their latest study, the group injected purified luciferase from the United States species into larvae of the Brazilian species, which then produced blue light. The nonluminescent Brazilian species is more abundant in nature than the United States species, so a larger amount of the material could be obtained for study purposes, especially to characterize the luciferin (keroplatin) present in both species.

In 2019, the group discovered and described Neoceroplatus betaryensis, a new species of fungus gnat, in collaboration with Cassius Stevani, a professor at the University of São Paulo’s Institute of Chemistry (IQ-USP). It was the first blue light-emitting insect found in South America and was detected in a privately held forest reserve near the Upper Ribeira State Tourist Park (PETAR) in the southern portion of the state of São Paulo. A close relative of O. fultoni, N. betaryensis inhabits fallen tree trunks in humid places (read more at: agencia.fapesp.br/31797).

“We show that the bioluminescent system of this Brazilian species is identical to that of O. fultoni. However, the insect is very rare, and so it’s hard to obtain sufficient material for research purposes,” Viviani said.

The researchers are now cloning the insect’s luciferase and characterizing it in molecular terms. They are also analyzing the chemical structure of its luciferin and the morphology of its lanterns.

“Once all this has been determined, we’ll be able to synthesize the luciferin and luciferase in the lab and use these systems in a range of biotech applications, such as studying cells. This will help us understand more about human diseases, among other things,” Viviani said.

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

A new brilliantly blue-emitting luciferin-luciferase system from Orfelia fultoni and Keroplatinae (Diptera) by Vadim R. Viviani, Jaqueline R. Silva, Danilo T. Amaral, Vanessa R. Bevilaqua, Fabio C. Abdalla, Bruce R. Branchini & Carl H. Johnson. Scientific Reports volume 10, Article number: 9608 (2020) DOI: https://doi.org/10.1038/s41598-020-66286-1 Published 15 June 2020

This paper is open access.

Viburnum and a new kind of structural colo(u)r

I love structural colo(u) and the first such story here was this February 7, 2013 posting, which is where you’ll find the image below,

AGELESS BRILLIANCE: Although the pigment-derived leaf color of this decades-old specimen of the African perennial Pollia condensata has faded, the fruit still maintains its intense metallic-blue iridescence.COURTESY OF P.J. RUDALL [downloaded from http://www.the-scientist.com/?articles.view/articleNo/34200/title/Color-from-Structure/]

Those berries are stunning especially when you realize they are part of a long-dead Pollia plant. Scientist, Rox Middleton of University of Bristol (UK) was studying the structures that render the Pollia plant’s berries (fruit) blue when she decided to study another, more conveniently accessible plant with blue fruit. That’s when she got a surprise (from an August 11, 2020 article by Véronique Greenwood for the New York Times),

Big, leafy viburnum bushes have lined yards in the United States and Europe for decades — their domes of blossoms have an understated attractiveness. But once the flowers of the Viburnum tinus plant fade, the shrub makes something unusual: shiny, brilliantly blue fruit.

Scientists had noticed that pigments related to those in blueberries exist in viburnum fruit, and assumed that this must be the source of their odd hue. Blue fruit, after all, is rare. But researchers reported last week in Current Biology that viburnum’s blue is actually created by layers of molecules arranged under the surface of the skin, a form of what scientists call structural color. By means still unknown, the plant’s cells create thin slabs of fat [emphasis mine] arranged in a stack, like the flakes of puff pastry, and their peculiar gleam is the result.

Rox Middleton, a researcher at University of Bristol in England and an author of the new paper, had been studying the African pollia plant, which produces its own exotic blue fruit. But viburnum fruit were everywhere, and she realized that their blue had not been well-studied. Along with Miranda Sinnott-Armstrong, a researcher at the University of Colorado, Boulder, and other colleagues, she set out to take a closer look at the fruit’s skin.

The pollia fruit’s blue is a form of structural color, in which light bounces off a regularly spaced arrangement of tiny structures such that certain wavelengths, usually those that look blue or green to us, are reflected back at the viewer. In pollia fruit, the color comes from light interacting with thin sheets of cellulose packed together. At first the team thought there would be something similar in viburnum. But they saw no cellulose stacks.

The research team has concluded that all it comes down the arrangement of fat molecules, which are also responsible for the cloudier, metallic blue in viburnum berries,

Caption Closeup of viburnum tinus. Credit: Rox Middleton Courtesy University of Cambridge

I encourage you to read Greenwood’s August 11, 2020 article in its entirety. For those who like more details, there are two press releases. The first is an August 6, 2020 University of Cambridge press release on EurekAlert. Middleton completed the ‘Virbunum’ research while completing her PhD at Cambridge. As mentioned earlier, Middleton is currently a researcher at the University of Bristol and they issued an August 11, 2020 press release touting her accomplishment.

Finally, for the insatiably curious, here’s a link to and a citation for the paper,

Viburnum tinus Fruits Use Lipids to Produce Metallic Blue Structural Color by Rox Middleton, Miranda Sinnott-Armstrong, Yu Ogawa, Gianni Jacucci, Edwige Moyroud, Paula J. Rudall, Chrissie Prychid, Maria Conejero, Beverley J. Glover, Michael J. Donoghue, Silvia Vignolini. Current Biology DOI:https://doi.org/10.1016/j.cub.2020.07.005 Published:August 06, 2020

This paper is behind a paywall.

Effective anti-icing with nanostructures modeled on moth eyes

According to an August 4, 2020 news item on ScienceDaily the ‘Ice-phobic’ properties of moths’ eyes have inspired a new technology,

Researchers have been working for decades on improving the anti-icing performance of functional surfaces. Ice accumulation on aircraft wings, for instance, can reduce lifting force, block moving parts and cause disastrous problems.

Research in the journal AIP [American Institute of Physics] Advances, from AIP Publishing, investigates a unique nanostructure, modeled on moth eyes, that has anti-icing properties. Moth eyes are of interest because they have a distinct ice-phobic and transparent surface.

An August 4, 2020 AIP news release (also on EurekAlert), which originated the news item, delves further into how they fabricated ‘moth-like eye’ structures at the nanoscale,

The researchers fabricated the moth eye nanostructure on a quartz substrate that was covered with a paraffin layer to isolate it from a cold and humid environment. Paraffin wax was chosen as a coating material due to its low thermal conductivity, easy coating and original water repellency.

“We evaluated the anti-icing properties of this unique nanostructure covered with paraffin in terms of adhesion strength, freezing time and mimicking rain sustainability,” said Nguyen Ba Duc, one of the authors.

Ice accumulation on energy transmission systems, vehicles and ships in a harsh environment often leads to massive destruction and contributes to serious accidents.

The researchers found the moth eyes nanostructure surface coated in paraffin exhibited greatly improved anti-icing performance, indicating the advantage of combining original water repellency and a unique heat-delaying structure. The paraffin interfered in the icing process in both water droplet and freezing rain experiments.

The number of air blocks trapped inside the nanostructure also contributed to delaying heat transfer, leading to an increase in freezing time of the attached water droplets.

“We also determined this unique nanostructure sample is suitable for optical applications, such as eyeglasses, as it has high transparency and anti-reflective properties,” said Ba Duc.

The high transparency and anti-reflective effects were due to the nanostructure being modeled on moth eyes, which have these transparent and anti-reflective properties.

Ice accumulation on a bare coated, nanostructure (NS) and nanostructure covered in paraffin (NSP) samples after a freezing test CREDIT: Nguyen Ba Duc

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

Investigate on structure for transparent anti-icing surfaces by Nguyen Ba Duc and Nguyen Thanh Binh. AIP Advances 10, 085101 (2020); https://doi.org/10.1063/5.0019119

This paper is open access.

Elinor Wonders Why—teaching biomimicry to children aged 3 to 6 years old

This new US Public Broadcasting Service (PBS) series for children was first announced a year in advance in a May 29, 2019 PBS news release,

Today [May 29, 2019], PBS KIDS announced the animated series ELINOR WONDERS WHY, set to premiere Labor Day [September 7] 2020. ELINOR WONDERS WHY aims to encourage children to follow their curiosity, ask questions when they don’t understand and find answers using science inquiry skills. The main character Elinor, the most observant and curious bunny rabbit in Animal Town, will introduce kids ages 3-5 to science, nature and community through adventures with her friends. This new multiplatform series, created by Jorge Cham and Daniel Whiteson and produced in partnership with Pipeline Studios, will debut nationwide on PBS stations, the PBS KIDS 24/7 channel and PBS KIDS digital platforms. 

The stories in ELINOR WONDERS WHY center around Elinor and her friends Ari, a funny and imaginative bat, and Olive, a perceptive and warm elephant. As kids explore Animal Town, they will meet all kinds of interesting, funny, and quirky characters, each with something to teach us about respecting others, the importance of diversity, caring for the environment, and working together to solve problems. In each episode, Elinor models the foundational practices of science inquiry and engineering design — including her amazing powers of observation and willingness to ask questions and investigate. When she encounters something she doesn’t understand, like why birds have feathers or how tiny ants build massive anthills, she just can’t let it go until she figures it out. And in discovering the answers, Elinor often learns something about nature’s ingenious inventions and how they can connect to ideas in our designed world, and what it takes to live in a community. ELINOR WONDERS WHY encourages children and parents to ask their own questions and experience the joy of discovery and understanding together.

Starr Rhett Rocque’s Sept. 7, 2020 article for Fast Company offers more detail,

Elinor Wonders Why is a STEM [science, technology, engineering, and mathematics]-based cartoon series created by Daniel Whiteson, a physicist and astronomer, and Jorge Cham, a cartoonist and robotics engineer. They’re both parents of small children, so they understand how to encourage curiosity through science and how to break down complex concepts.

Cham and Whiteson have been partners for years, working together on PhD Comics, which is a webcomic, YouTube, and podcast universe dedicated to PhD student humor. Linda Simensky, head of content for PBS Kids, had been a fan of their work, and when the opportunity to create a preschool science show that focuses on biomimicry came up, she figured they’d be great for the job.

“Biomimicry is basically taking things that you learn in nature and in the outdoors and in the natural world, and using them for inventions and for innovation science,” says Simensky. “The classic example that they use in the pilot is how Velcro was designed. Basically, it was inspired by someone getting burdock stuck to his pants, and that’s what inspired Velcro, so that’s the classic example of finding something in nature that solves a problem that you need to solve in real life.”

Elinor Wonders Why centers around Elinor (named after Cham’s daughter), a curious and observant rabbit living in Animal Town who goes on various adventures. In the upcoming premiere, Elinor plays hide-and-go-seek with her friends and finds out how animals hide in nature. …

Rocque went on to interview Cham, Whiteson, and Simensky,

FC: Describe the overall process of “dumbing down” highly sophisticated content for a younger audience. Was it harder than you thought?

JC: There was definitely a learning curve, but fortunately everyone at PBS, our team of science and education specialists have been great collaborators and guides. We don’t really believe in the phrase “dumbing down.” …

DW: Something important for us was to make each episode about a single question that a real kid would have. We looked for topics that any typical kid would think, “Huh, I do wonder why that is?” The kinds of questions they might ask when they look at their own world, like, “Why do birds have feathers?” or “Why do lizards sit in the sun?” It’s also important for us that the kids in the show play an active part in finding the answers, so we pick questions that kids could answer themselves using basic scientific thinking and simple tools, simple experiments, making observations, and comparing and contrasting. This made the questions and answers accessible, and also hopefully provides a model for them to follow at home.

LS: The part of it that’s the hardest is getting everything to work for the same age group. That’s the first thing. So, when you’re doing that, you’re doing several things at a time. You’re coming up with the idea for the show and you have to make sure that you know exactly who your age group is, and in the case of Elinor, it’s kids between the ages of 3 and 6. That’s a typical preschool group, and that includes kids who are in kindergarten, and even within 3 to 6, that’s obviously a pretty big range of kids. …

PBS does have an Elinor Wonders Why website but some of the materials (videos) are restricted to viewers based in the US. As for broadcast times, check your local PBS station, should you have one.