Green method developed for making artificial spider silk

sc604 — Mon, 10 Jul 2017 19:00:00 +0000

A team of architects and chemists from the ̽��ֱ�� of Cambridge has designed super-stretchy and strong fibres which are almost entirely composed of water, and could be used to make textiles, sensors and other materials. ̽��ֱ��fibres, which resemble miniature bungee cords as they can absorb large amounts of energy, are sustainable, non-toxic and can be made at room temperature.

This new method not only improves upon earlier methods of making synthetic spider silk, since it does not require high energy procedures or extensive use of harmful solvents, but it could substantially improve methods of making synthetic fibres of all kinds, since other types of synthetic fibres also rely on high-energy, toxic methods. ̽��ֱ��results are reported in the journal Proceedings of the National Academy of Sciences.

Spider silk is one of nature’s strongest materials, and scientists have been attempting to mimic its properties for a range of applications, with varying degrees of success. “We have yet to fully recreate the elegance with which spiders spin silk,” said co-author Dr Darshil Shah from Cambridge’s Department of Architecture.

̽��ֱ��fibres designed by the Cambridge team are “spun” from a soupy material called a hydrogel, which is 98% water. ̽��ֱ��remaining 2% of the hydrogel is made of silica and cellulose, both naturally available materials, held together in a network by barrel-shaped molecular “handcuffs” known as cucurbiturils. ̽��ֱ��chemical interactions between the different components enable long fibres to be pulled from the gel.

̽��ֱ��fibres are pulled from the hydrogel, forming long, extremely thin threads – a few millionths of a metre in diameter. After roughly 30 seconds, the water evaporates, leaving a fibre which is both strong and stretchy.

“Although our fibres are not as strong as the strongest spider silks, they can support stresses in the range of 100 to 150 megapascals, which is similar to other synthetic and natural silks,” said Shah. “However, our fibres are non-toxic and far less energy-intensive to make.”

̽��ֱ��fibres are capable of self-assembly at room temperature, and are held together by supramolecular host-guest chemistry, which relies on forces other than covalent bonds, where atoms share electrons.

“When you look at these fibres, you can see a range of different forces holding them together at different scales,” said Yuchao Wu, a PhD student in Cambridge’s Department of Chemistry, and the paper’s lead author. “It’s like a hierarchy that results in a complex combination of properties.”

̽��ֱ��strength of the fibres exceeds that of other synthetic fibres, such as cellulose-based viscose and artificial silks, as well as natural fibres such as human or animal hair.

In addition to its strength, the fibres also show very high damping capacity, meaning that they can absorb large amounts of energy, similar to a bungee cord. There are very few synthetic fibres which have this capacity, but high damping is one of the special characteristics of spider silk. ̽��ֱ��researchers found that the damping capacity in some cases even exceeded that of natural silks.

“We think that this method of making fibres could be a sustainable alternative to current manufacturing methods,” said Shah. ̽��ֱ��researchers plan to explore the chemistry of the fibres further, including making yarns and braided fibres.

This research is the result of a collaboration between the Melville Laboratory for Polymer Synthesis in the Department of Chemistry, led by Professor Oren Scherman; and the Centre for Natural Material Innovation in the Department of Architecture, led by Dr Michael Ramage. ̽��ֱ��two groups have a mutual interest in natural and nature-inspired materials, processes and their applications across different scales and disciplines.

̽��ֱ��research is supported by the UK Engineering and Physical Sciences Research Council (EPSRC) and the Leverhulme Trust.

Reference
Yuchao Wu et al. ‘Bioinspired supramolecular fibers drawn from a multiphase self-assembled hydrogel.’ Proceedings of the National Academy of Sciences (2017). DOI: 10.1073/pnas.1705380114

Researchers have designed a super stretchy, strong and sustainable material that mimics the qualities of spider silk, and is ‘spun’ from a material that is 98% water.

This method of making fibres could be a sustainable alternative to current manufacturing methods.

Darshil Shah

William Waterway

Spider web necklace with pearls of dew

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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Lighting up plant cells to engineer biology

bjb42 — Thu, 05 Apr 2012 00:04:56 +0000

A new technique using fluorescence to automatically measure and map cellular activity in living plant tissue will contribute to better computer models that are at the heart of synthetic biology, the attempts to engineer living systems.

̽��ֱ��team at the ̽��ֱ�� of Cambridge’s Department of Plant Sciences, led by Dr Jim Haseloff, have been working to uncover the mysteries of biological systems in certain plants - characterised by the highly complex genetic and cellular networks which are locked in a vast network of interactions - resulting in self-repair and reproduction in the organism.

These evolved biological systems are capable of creating structures of a hugely complex nature, far more sophisticated than the most advanced man-made materials - which the plants do in a renewable and, if it could be harnessed, a potentially very cheap way.

By creating new techniques allowing ever more detailed study of the cellular activity of plants, scientists believe it may be possible to reprogram living systems - which has given rise to an emerging field known as Synthetic Biology, which applies engineering principles to the building blocks of organic life.

“Synthetic Biology is based on the use of reusable components and numerical models - for the design of biological circuits, in a way that has become routine in other fields of engineering,” says Haseloff.

“Techniques such as the one we have developed will help us to discover more about the thrilling complexities of life at this level, and how we might be able to utilise the power of plants and their cellular networks in engineering - potentially revolutionising the way we engage with organic matter.”

At the moment, Synthetic Biology is in its infancy, and there is a critical need for improved techniques for measuring biological parameters within still living systems of cells.

This new technique - outlined in a paper published on the Nature journal’s Methods website on Sunday - involves fluorescent proteins, such as those originally found in certain jellyfish and corals. ̽��ֱ��proteins are used to mark and consequently identify specific parts of cells - the nuclei and membrane - mapping the development, position and geometry of the cellular make-up in the living plant tissue.

̽��ֱ��researchers combine the advanced imaging processes with algorithms that automate quantitative analysis of cell growth and genetic activity within living organisms to precisely reconstruct cellular dynamics - and produce a numerical description that can be used to inform computer models.

In this way the cellular properties in intact plant tissue can be observed in depth – and be converted to mathematical descriptions of the living processes. This opens the door for the construction of new computer models for Synthetic Biology and the engineering of living tissue.

Adds Haseloff: “We have been able to use the very latest technical advances in microscopy for quantitative analysis of cell size, shape and gene activity from images of living plant tissues. This new technique, which we call in planta cytometry, will contribute to a greater understanding of plant development, physiology and help pave the way for advances in biological engineering.”

Cambridge researchers have developed a new technique for measuring and mapping gene and cell activity through fluorescence in living plant tissue.

Techniques such as the one we have developed will help us to discover more about the thrilling complexities of life at this level.

Dr Jim Haseloff

Fernan Federici from the Haseloff lab

Root of Arabidopsis thaliana with green fluorescent protein decorating cell membrane and red fluorescent protein marking nuclei.

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̽��ֱ�� of Cambridge - synthetic

Green method developed for making artificial spider silk

Lighting up plant cells to engineer biology