Tag Archives: spider silk

Studying the “feather-legged lace weaver’s” (Uloborus plumipes) web weaving abilities

It’s more commonly known in Britain as a ‘garden centre spider’ but I like ‘feather-legged lace weaver’ better. Before getting to the story, here’s an image of the spider in question,

The "garden center spider" (Uloborus plumipes) combs and pulls its silk and builds up an electrostatic charge to create sticky filaments just a few nanometers thick. It could inspire a new way to make super long and strong nanofibers. Credit: Hartmut Kronenberger & Katrin Kronenberger (Oxford University)

The “garden center spider” (Uloborus plumipes) combs and pulls its silk and builds up an electrostatic charge to create sticky filaments just a few nanometers thick. It could inspire a new way to make super long and strong nanofibers.
Credit: Hartmut Kronenberger & Katrin Kronenberger (Oxford University)

A Jan. 27, 2015 Oxford University press release (also on EurekAlert and in a Jan. 29, 2015 news item on Azonano) describes the research,

A spider commonly found in garden centres in Britain is giving fresh insights into how to spin incredibly long and strong fibres just a few nanometres thick.

The majority of spiders spin silk threads several micrometres thick but unusually the ‘garden centre spider’ or ‘feather-legged lace weaver’ [1] Uloborus plumipes can spin nano-scale filaments. Now an Oxford University team think they are closer to understanding how this is done. Their findings could lead to technologies that would enable the commercial spinning of nano-scale filaments.

The research was carried out by Katrin Kronenberger and Fritz Vollrath of Oxford University’s Department of Zoology and is reported in the journal Biology Letters.

Instead of using sticky blobs of glue on their threads to capture prey Uloborus uses a more ancient technique – dry capture threads made of thousands of nano-scale filaments that it is thought to electrically charge to create these fluffed-up catching ropes.

To discover the secrets of its nano-fibres the Oxford researchers collected adult female Uloborus lace weavers from garden centres in Hampshire, UK. They then took photographs and videos of the spiders’ spinning action and used three different microscopy techniques to examine the spiders’ silk-generating organs. Of particular interest was the cribellum, an ancient spinning organ not found in many spiders and consisting of one or two plates densely covered in tiny silk outlet nozzles (spigots).

Uloborus has unique cribellar glands, amongst the smallest silk glands of any spider, and it’s these that yield the ultra-fine ‘catching wool’ of its prey capture thread,’ said Dr Katrin Kronenberger of Oxford University’s Department of Zoology, the report’s first author. ‘The raw material, silk dope, is funnelled through exceptionally narrow and long ducts into tiny spinning nozzles or spigots. Importantly, the silk seems to form only just before it emerges at the uniquely-shaped spigots of this spider.’

False colour SEM image of a small part of the cribellum spinning plate with its unique silk outlets Image: Katrin Kronenberger (Oxford University) & David Johnston (University of Southampton)

False colour SEM image of a small part of the cribellum spinning plate with its unique silk outlets
Image: Katrin Kronenberger (Oxford University) & David Johnston (University of Southampton)

The cribellum of Uloborus is covered with thousands of tiny silk-producing units combining ducts that average 500 nanometres in length and spigots that narrow to a diameter of around 50 nanometres.

‘The swathe of gossamer, made of thousands of filaments, emerging from these spigots is actively combed out by the spider onto the capture thread’s core fibres using specialist hairs on its hind legs,’ said Professor Fritz Vollrath, the other author of the work. ‘This combing and hackling – violently pulling the thread – charges the fibres and the electrostatic interaction of this combination spinning process leads to regularly spaced, wool-like ‘puffs’ covering the capture threads. The extreme thinness of each filament, in addition to the charges applied during spinning, provides Van der Waals adhesion. And this makes these puffs immensely sticky.’

The cribellate capture thread of Uloborus plumipes, with its characteristic 'puffs', imaged with a Scanning Electron Microscope (SEM) Image: Fritz Vollrath (Oxford University)

The cribellate capture thread of Uloborus plumipes, with its characteristic ‘puffs’, imaged with a Scanning Electron Microscope (SEM)
Image: Fritz Vollrath (Oxford University)

Conventionally, synthetic polymers fibres are produced by hot-melt extrusion: these typically have diameters of 10 micrometres or above. But because thread diameter is integral to filament strength, technology that could enable the commercial production of nano-scale filaments would make it possible to manufacture stronger and longer fibres.

‘Studying this spider is giving us valuable insights into how it creates nano-scale filaments,’ said Professor Vollrath. ‘If we could reproduce its neat trick of electro-spinning nano-fibres we could pave the way for a highly versatile and efficient new kind of polymer processing technology.’

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

Spiders spinning electrically charged nano-fibres by Katrin Kronenberger and Fritz Vollrath. January 2015 Volume: 11 Issue: 1 DOI: 10.1098/rsbl.2014.0813 Published 28 January 2015

This is an open access paper. Note: Sometimes journals close access after a certain number of days so the paper may not be freely available after a certain time period.

Music on the web, a spider’s web, that is

I was expecting to see Markus Buehler and MIT (Massachusetts Institute of Technology) mentioned in this latest work on spiderwebs and music. Surprise! This latest research is from three universities in the UK as per a June 3, 2014 news item on ScienceDaily,

Spider silk transmits vibrations across a wide range of frequencies so that, when plucked like a guitar string, its sound carries information about prey, mates, and even the structural integrity of a web.

The discovery was made by researchers from the Universities of Oxford, Strathclyde, and Sheffield who fired bullets and lasers at spider silk to study how it vibrates. They found that, uniquely, when compared to other materials, spider silk can be tuned to a wide range of harmonics. The findings, to be reported in the journal Advanced Materials, not only reveal more about spiders but could also inspire a wide range of new technologies, such as tiny light-weight sensors.

A June 3, 2014 University of Oxford news release (also on EurekAlert), which originated the news item, explains the research and describes how it was conducted (firing bullets?),

‘Most spiders have poor eyesight and rely almost exclusively on the vibration of the silk in their web for sensory information,’ said Beth Mortimer of the Oxford Silk Group at Oxford University, who led the research. ‘The sound of silk can tell them what type of meal is entangled in their net and about the intentions and quality of a prospective mate. By plucking the silk like a guitar string and listening to the ‘echoes’ the spider can also assess the condition of its web.’

‘Most spiders have poor eyesight and rely almost exclusively on the vibration of the silk in their web for sensory information,’ said Beth Mortimer of the Oxford Silk Group at Oxford University, who led the research. ‘The sound of silk can tell them what type of meal is entangled in their net and about the intentions and quality of a prospective mate. By plucking the silk like a guitar string and listening to the ‘echoes’ the spider can also assess the condition of its web.’

This quality is used by the spider in its web by ‘tuning’ the silk: controlling and adjusting both the inherent properties of the silk, and the tensions and interconnectivities of the silk threads that make up the web. To study the sonic properties of the spider’s gossamer threads the researchers used ultra-high-speed cameras to film the threads as they responded to the impact of bullets. [emphasis mine] In addition, lasers were used to make detailed measurements of even the smallest vibration.

‘The fact that spiders can receive these nanometre vibrations with organs on each of their legs, called slit sensillae, really exemplifies the impact of our research about silk properties found in our study,’ said Dr Shira Gordon of the University of Strathclyde, an author involved in this research.

‘These findings further demonstrate the outstanding properties of many spider silks that are able to combine exceptional toughness with the ability to transfer delicate information,’ said Professor Fritz Vollrath of the Oxford Silk Group at Oxford University, an author of the paper. ‘These are traits that would be very useful in light-weight engineering and might lead to novel, built-in ‘intelligent’ sensors and actuators.’

Dr Chris Holland of the University of Sheffield, an author of the paper, said: ‘Spider silks are well known for their impressive mechanical properties, but the vibrational properties have been relatively overlooked and now we find that they are also an awesome communication tool. Yet again spiders continue to impress us in more ways than we can imagine.’

Beth Mortimer said: ‘It may even be that spiders set out to make a web that ‘sounds right’ as its sonic properties are intimately related to factors such as strength and flexibility.’

The research paper has not yet been published in Advanced Materials (I checked this morning, June 4, 2014).

However, there is this video from the researchers,

As for Markus Buehler’s work at MIT, you can find out more in my Nov. 28, 2012 posting, Producing stronger silk musically.

Producing stronger silk musically

Markus Buehler and his interdisciplinary team (my previous posts on their work includes Gossamer silk that withstands hurricane force winds and Music, math, and spiderwebs) have synthesized a new material based on spider silk. From the Nov. 28, 2012 news item on ScienceDaily,

Pound for pound, spider silk is one of the strongest materials known: Research by MIT’s [Massachusetts Institute of Technology] Markus Buehler has helped explain that this strength arises from silk’s unusual hierarchical arrangement of protein building blocks.

Now Buehler — together with David Kaplan of Tufts University and Joyce Wong of Boston University — has synthesized new variants on silk’s natural structure, and found a method for making further improvements in the synthetic material.

And an ear for music, it turns out, might be a key to making those structural improvements.

Here’s Buehler describing the work in an MIT video clip,

The Nov. 28, 2012 MIT news release by David Chandler provides more details,

Buehler’s previous research has determined that fibers with a particular structure — highly ordered, layered protein structures alternating with densely packed, tangled clumps of proteins (ABABAB) — help to give silk its exceptional properties. For this initial attempt at synthesizing a new material, the team chose to look instead at patterns in which one of the structures occurred in triplets (AAAB and BBBA).

Making such structures is no simple task. Kaplan, a chemical and biomedical engineer, modified silk-producing genes to produce these new sequences of proteins. Then Wong, a bioengineer and materials scientist, created a microfluidic device that mimicked the spider’s silk-spinning organ, which is called a spinneret.

Even after the detailed computer modeling that went into it, the outcome came as a bit of a surprise, Buehler says. One of the new materials produced very strong protein molecules — but these did not stick together as a thread. The other produced weaker protein molecules that adhered well and formed a good thread. “This taught us that it’s not sufficient to consider the properties of the protein molecules alone,” he says. “Rather, [one must] think about how they can combine to form a well-connected network at a larger scale.”

The different levels of silk’s structure, Buehler says, are analogous to the hierarchical elements that make up a musical composition — including pitch, range, dynamics and tempo. The team enlisted the help of composer John McDonald, a professor of music at Tufts, and MIT postdoc David Spivak, a mathematician who specializes in a field called category theory. Together, using analytical tools derived from category theory to describe the protein structures, the team figured out how to translate the details of the artificial silk’s structure into musical compositions.

The differences were quite distinct: The strong but useless protein molecules translated into music that was aggressive and harsh, Buehler says, while the ones that formed usable fibers sound much softer and more fluid.

Combining materials modeling with mathematical and musical tools, Buehler says, could provide a much faster way of designing new biosynthesized materials, replacing the trial-and-error approach that prevails today. Genetically engineering organisms to produce materials is a long, painstaking process, he says, but this work “has taught us a new approach, a fundamental lesson” in combining experiment, theory and simulation to speed up the discovery process.

Materials produced this way — which can be done under environmentally benign, room-temperature conditions — could lead to new building blocks for tissue engineering or other uses, Buehler says: scaffolds for replacement organs, skin, blood vessels, or even new materials for use in civil engineering.

It may be that the complex structures of music can reveal the underlying complex structures of biomaterials found in nature, Buehler says. “There might be an underlying structural expression in music that tells us more about the proteins that make up our bodies. After all, our organs — including the brain — are made from these building blocks, and humans’ expression of music may inadvertently include more information that we are aware of.”

“Nobody has tapped into this,” he says, adding that with the breadth of his multidisciplinary team, “We could do this — making better bio-inspired materials by using music, and using music to better understand biology.”

At the end of Chandler’s news release there’s a notice about a summer course with Markus Buehler,

For those interested in the work Professor Buehler is doing, you may also be interested to know that he is offering a short course on campus this summer called Materials By Design.

Materials By Design
June 17-20, 2013
shortprograms.mit.edu/mbd

Through lectures and hands-on labs, participants will learn how materials failure, studied from a first principles perspective, can be applied in an effective “learning-from-failure approach” to design and make novel materials. Participants will also learn how superior material properties in nature and biology can be mimicked in bioinspired materials for applications in new technology. This course will be of interest to scientists, engineers, managers, and policy makers working in the area of materials design, development, manufacturing, and testing. [emphasis mine]

I wasn’t expecting to see managers and policy makers as possible students for this course.

By the way, Buehler is not the only scientist to make a connection between music and biology (although he seems to be the only person using the concept for applications), there’s also geneticist and biophysicist, Mae Wan Ho and her notion of quantum jazz. From the Quantum Jazz Biology* article by David Reilly in the June 23, 2010 Isis Report,

I use the analogy of ‘quantum jazz’ to express the quantum coherence of the organism. It goes through a fantastic range of space and time scales, from the tiniest atom or subatomic particle to the whole organism and beyond. Organisms communicate with other organisms, and are attuned to natural rhythms, so they have circadian rhythms, annual rhythms, and so on. At the other extreme, you have very fast reactions that take place in femtoseconds. And all these rhythms are coordinated, there is evidence for that.

Goats, spider silk, and silkworms

A few years ago (2008), I attended the Cascadia Nanotech Symposium organized by the now defunct, Nanotech BC (British Columbia, Canada) and heard Dr. Frank Ko speak. He is a Canada Research Chair at the University of British Columbia (UBC) who leads the Advanced Fibrous Materials Laboratory and, in his talk, he mentioned that he had added spider genes to goats with the intention of easing the process of spinning goat’s milk thereby exploiting spider silk’s properties.

I’m never especially comfortable about mixing genes between species that, as far as I know, would never have occasion to mingle their genetic material together. It’s a little too close to ‘The Isle of Dr. Moreau’ (Victor Hugo’s novel which I have never read but have heard about). But there were people who had some similar concerns about electricity, which I take for granted, violating the natural order of things as per Carolyn Marvin’s book, When old technologies were new. Consequently, I’m willing to think about it but not terribly happy to do it.

Getting back to spider silk and Dr. Ko’s work, he and others are very interested in exploiting the strength inherent in spider silk. Here’s a description of that strength from an article by David Zax on Fast Company,

Oftentimes, nature is better at building stuff than we are. Spider silk is an example. The tiny threads spun by our eight-legged friends has a tensile strength comparable to high-grade steel. If humans could harness the spider and turn it into a manufacturing agent, the industrial and commercial potentials could be immense. One problem, though: Spidey hasn’t been cooperating. Spiders just don’t spin the stuff in great quantities, and there is no commercially viable way of mass-producing spider silk.

In looking at Dr. Ko’s webpage I see that adding a spider gene to goats may have been his solution to the problem of producing more spider silk (and perhaps other issues as well),

An internationally recognized expert in 3-D complex fiber architecture for structural toughening of composites Professor Ko’s pioneering work on the development of continuous nanocomposite fibrils by co-electrospinning has provided a new pathway to connect nanomaterials to macrostructural design. With an objective to understand the structural basis for the outstanding combination of strength and toughness in spider silk Professor Ko has played a leading role in the study of nanocomposite fibrils from recombinant spider silk. It was demonstrated that 10X increase in strength and 5X increase in modulus were attainable with the addition of 1-3 weight % of carbon nanotube to the recombinant spider silk. Research has been extended to various filler geometry that include graphite nanoplatelet (GNP); nanoparticles such as nanodiamonds and various functional particles.

Zax’s article highlights a different approach to producing greater quantities of spider silk,

There is, however, already a silkworm industry, which yields most of the silk–less strong than the spider’s–that we’re familiar with. A few scientists got a bright idea: what if you could make the silkworm, which is already equipped for industry, spin spider silk?

Notre Dame, the University of Wyoming, and Kraig Biocraft Laboratories, Inc. joined heads, and recently announced that they had succeeded in genetically engineering silkworms so that they produce artificial spider silks. Several biologists teamed up to splice certain DNA from spiders into the genomes of silkworms. The altered silkworms now spin cocoons that are a mixture of silkworm silk and spider silk. Though the tensile strength of the altered silk still falls well short of that of pure spider silk, it’s a step in the right direction.

I can certainly see benefits to this but I sometimes wonder if humans have enough humility and foresight as we embark on ever more subtle manipulations of life.

ETA October 29, 2010: If you are interested in the goat/spider issue, take a look at Andrew Manard’s October 27, 2010 posting on his 2020 Science blog. He’s running a poll on the question,

… why not take the gene responsible for making spider silk, and splice it into a goat [to produce more spider silk]?

Be sure to take a look at the comments, if you’re interested in the history of the technique, which apparently stretches back to the 1950s!

Canada Foundation for Innovation “World’s Best”?; Ping hoodie, clothing that networks socially; life protection clothing; getting spiders to weave building materials?; open access archive for nano papers

The headline for the news release on Marketwire (via the Canadian Science Policy site) is: Canada Foundation for Innovation(CFI) Practices is Called ‘World’s Best’. As it’s been a bit slow for news here I began wondering ‘which practices in which countries are being compared’? After reviewing the reports quickly, I can’t answer the question. There are no bibliographies in any of the three reports related to this KPMG study while the footnotes make reference only to other KPMG and Canadian studies. It was a bit of surprise, I was expecting to see reports from other countries and/or from international organizations and some insight into their analysis as comparing agencies in different countries can be complicated.

I’m not sure how they arrived at their conclusion although they provide some interesting data. From the Overall Evaluation report (p. 28 PDF, p. 24 print),

Exhibit [Table] 4.16 shows that, on average, there have been about 6.4 collaborations with end-users per PL/PU in the past year, three-quarters of which used the CFI projects as key resources, and about 10.2 collaborations per Department Head, about 70% of which using CFI projects in a significant way. For PLs/PUs, there are only small differences in use of CFI projects as a key resource by type of end-user, but Department Heads show more variation in the use of CFI project by type of user; it is unknown if this is significant.

Note that 64% of PL/PUs’ and 80% of Department Heads’ end-user collaborations, respectively, are with Canadian organizations; there is a significant international component (with OMS data suggesting that the CFI projects are a significant attractor for international organizations to collaborate [emphasis mine]).

It certainly seems laudable although I question whether you can conclude that the CFI is a significant international organization attractor by inference alone. Shouldn’t this be backed up with another instrument, such as a questionnaire for a survey/poll of the international organizations, asking why they are collaborating with Canadian scientists? I was not able to find any mention of such a survey or poll taking place.

From everything I hear, Canadians are excellent at academic science research and attracting researchers from around the world and because of our penchant for collaboration we (as they say) “punch above our weight.” I just wish this report did a better job of providing evidence for its assertions about the CFI’s ‘best practices’.

Ping hoodie

Thanks to Adrian Covert’s article on Fast Company, I found information about a prototype for a piece of wearable computing, the Ping hoodie. From Covert’s article,

The Ping clothing concept makes use of embedded electronics and haptics controlled by the Arduino Lilypad system, which transmits to your device (most likely a smartphone) using the Lylipad Xbee. This tech serves as the core interface between you and the information you need. If someone special is sending you a call or text, you can set the hoodie to vibrate in a specific manner, letting you know it’s them. Actions as simple as lifting or dropping the hood can be used to send status updates and messages on Facebook, with the potential to target certain groups of friends.

There’s more at Fast Company or you can check out electricfoxy where the designer, Jennifer Darmour has her site which is where I found this image,

Ping hoodie (wearable computing) designed by Jennifer Darmour at electricfoxy

Do go to Darmour’s site (although Fast Company offers a pretty good selection) if you want to see all the images including close ups of the fabric (don’t forget to scroll horizontally as well as vertically).

Clothing that protects your life

P2i, a company I’ve mentioned here before, has announced a ‘new’ revolutionary form of protective clothing. Actually, it sounds like an improvement rather than a revolutionary concept but maybe I’m getting jaded. From the news item on Nanowerk,

A revolutionary new generation of high-performance body armour, launched today, is lighter, more comfortable and more protective than any previous design, thanks to P2i’s liquid-repellent nano-coating technology.

The new G Tech Vest is a joint development between two world-class UK companies with very strong credentials for the life protection market: P2i, whose technology was originally developed to make soldiers’ protective clothing more effective against chemical attack; and Global Armour, which has been at the leading edge of product innovation in the armour industry for over 30 years.

The G Tech Vest employs brand-new lightweight materials, both in the physical armour itself (a closely-guarded trade secret) and the fabric that forms the armour into a garment. P2i’s technology reduces weight by avoiding the need for bulky durable water repellents and increases comfort by preserving the natural airflow and drape of the garment material.

I recently (April 15, 2010) made a comment about how modern soldiers are beginning to resemble medieval knights and this talk of armour certainly reinforces the impression.

Spiders weaving building materials?

Michael Berger at Nanowerk has written an in-depth article about spider silk and its possible application, amongst others, as a building material. He’s interviewed one of the authors (Markus J. Buehler) of a recent paper that lays out “… a framework for predicting the nanostructure of spider silk using atomistic principles.” More from the Spotlight article on Nanowerk,

In a paper published as the cover article in Applied Physics Letters on April 12, 2010 (“Atomistic model of the spider silk nanostructure”), [Sinan] Keten and Buehler demonstrate an innovative application of replica exchange molecular dynamics simulations on a key spider silk repeating sequence, resulting in the first atomistic level structure of spider silk.

More specifically, the MIT researchers found the formation of beta-sheet structures in poly-Ala rich parts of the structure, the presence of semi-extended GGX domains that form H-bonded 31 helix type structures and a complete lack of alpha-helical conformations in the molecular structures formed by the self-assembly of MaSp1 proteins. These results resolve controversies around the structure of the amorphous domains in silk, by illustrating for the first time that these semi-extended, well-oriented and more sparsely H-bonded structures that resemble 31 helices could be the molecular source of the large semi-crystalline fraction of silks and the so-called ‘pre-stretched’ configuration proposed for these domains.

Shy of reading the original research, which I likely wouldn’t understand easily, Berger’s article provides an excellent entry into the subject.

Open access archive for nano papers

My final item for today is about a project to give free access to papers on nanotechnology that they host and/or publish.  Hooray! It’s very frustrating to get stuck behind paywalls so I’m thrilled that there’s an agency offering free access. From the news item on Nanowerk,

The Nano Archive, the online open-access repository for nanoscience and nanotechnology, invites you to submit research papers to be published free online for users across the globe.

Submitted papers can include peer-reviewed articles, journal articles, review articles, conference and workshop papers, theses and dissertations, book chapters and sections, as well as multimedia and audio-visual materials. The Nano Archive also welcomes new, unpublished research results to be shared with the wider community.

The Nano Archive is part of the ICPC NanoNet project, funded by the EU under FP7. It brings together partners from the EU, Russia, India, China and Africa, and provides wider access to published nanoscience research and opportunities for collaboration between scientists in the EU and International Cooperation Partner Countries.

The Nano Archive currently hosts over 6000 papers. You can read more about the sponsoring agency, the ICPC (International Cooperation Partner Countries) NanoNet here. It has funding for four years and was started in 2008.