Spider silk is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

fibre or

silk Silk is a natural fiber, natural protein fiber, some forms of which can be weaving, woven into textiles. The protein fiber of silk is composed mainly of fibroin and is most commonly produced by certain insect larvae to form cocoon (silk), c ...

spun by

spider Spiders (order (biology), order Araneae) are air-breathing arthropods that have eight limbs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude spider silk, silk. They are the largest order of arachnids and ran ...

s. Spiders use silk to make

web Web most often refers to: * Spider web, a silken structure created by the animal * World Wide Web or the Web, an Internet-based hypertext system Web, WEB, or the Web may also refer to: Computing * WEB, a literate programming system created by ...

s or other structures that function as adhesive traps to catch prey, to entangle and restrain prey before biting, to transmit tactile information, or as

nest A nest is a structure built for certain animals to hold Egg (biology), eggs or young. Although nests are most closely associated with birds, members of all classes of vertebrates and some invertebrates construct nests. They may be composed of ...

s or cocoons to protect their offspring. They can use the silk to suspend themselves from height, to float through the air, or to glide away from predators. Most spiders vary the thickness and adhesiveness of their silk according to its use. In some cases, spiders may use silk as a food source. While methods have been developed to collect silk from a spider by force, gathering silk from many spiders is more difficult than from silk-spinning organisms such as silkworms. All spiders produce silk, although some spiders do not make webs. Silk is tied to courtship and mating. Silk produced by females provides a transmission channel for male vibratory courtship signals, while webs and draglines provide a substrate for female sex pheromones. Observations of male spiders producing silk during sexual interactions are common across widespread taxa. The function of male-produced silk in mating has received little study.

Properties

Structural

Structure of spider silk thread Modified

Silks have a hierarchical structure. The primary structure is the

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although over 500 amino acids exist in nature, by far the most important are the 22 α-amino acids incorporated into proteins. Only these 22 a ...

sequence of its proteins ( spidroin), mainly consisting of highly repetitive

glycine Glycine (symbol Gly or G; ) is an amino acid that has a single hydrogen atom as its side chain. It is the simplest stable amino acid. Glycine is one of the proteinogenic amino acids. It is encoded by all the codons starting with GG (G ...

and alanine blocks, which is why silks are often referred to as a block co-polymer. On a secondary level, the short side-chained alanine is mainly found in the crystalline domains ( beta sheets) of the nanofibril. Glycine is mostly found in the so-called amorphous matrix consisting of helical and beta turn structures. The interplay between the hard crystalline segments and the strained elastic semi-amorphous regions gives spider silk its extraordinary properties. Various compounds other than protein are used to enhance the fibre's properties. Pyrrolidine has

hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption (chemistry), absorption or adsorption from the surrounding Natural environment, environment, which is usually at normal or room temperature. If water mol ...

properties that keep the silk moist while warding off ant invasion. It occurs in high concentration in glue threads. Potassium hydrogen phosphate releases hydrogen ions in aqueous solution, resulting in a pH of about 4, making the silk

acid An acid is a molecule or ion capable of either donating a proton (i.e. Hydron, hydrogen cation, H+), known as a Brønsted–Lowry acid–base theory, Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis ...

ic and thus protecting it from

fungi A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...

and

bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

that would otherwise digest the protein. Potassium nitrate is believed to prevent the protein from denaturing in the acidic milieu.Heimer, S. (1988). Wunderbare Welt der Spinnen. ''Urania''. p. 12 Termonia introduced this first basic model of silk in 1994. He suggested crystallites embedded in an amorphous matrix interlinked with hydrogen bonds. Refinements to this model include: semi-crystalline regions were found as well as a fibrillar skin core model suggested for spider silk, later visualised by AFM and TEM. Sizes of the nanofibrillar structure and the crystalline and semi-crystalline regions were revealed by neutron scattering. The fibres' microstructural information and macroscopic mechanical properties are related. Ordered regions (i) mainly reorient by deformation for low-stretched fibres and (ii) the fraction of ordered regions increases progressively for higher fibre stretching.
File:0.Figure.png, Schematic of the spider's orb web, structural modules, and spider silk structure. On the left is shown a schematic drawing of an orb web. The red lines represent the dragline, radial line, and frame lines. The blue lines represent the spiral line, and the centre of the orb web is called the "hub". Sticky balls drawn in blue are made at equal intervals on the spiral line with viscous material secreted from the aggregate gland. Attachment cement secreted from the piriform gland is used to connect and fix different lines. Microscopically, the spider silk secondary structure is formed of spidroin with the structure shown on the right side. In the dragline and radial line, a crystalline β-sheet and an amorphous helical structure are interwoven. The large amount of β-spiral structure gives elastic properties to the capture part of the orb web. In the structural modules diagram, a microscopic structure of dragline and radial lines is shown, composed mainly of two proteins of MaSp1 and MaSp2, as shown in the upper central part. The spiral line has no crystalline β-sheet region.

Mechanical

Each spider and each type of silk has a set of mechanical properties optimised for their biological function. Most silks, in particular dragline silk, have exceptional mechanical properties. They exhibit a unique combination of high

tensile strength Ultimate tensile strength (also called UTS, tensile strength, TS, ultimate strength or F_\text in notation) is the maximum stress that a material can withstand while being stretched or pulled before breaking. In brittle materials, the ultimate ...

and extensibility (

ductility Ductility refers to the ability of a material to sustain significant plastic Deformation (engineering), deformation before fracture. Plastic deformation is the permanent distortion of a material under applied stress, as opposed to elastic def ...

). This enables a silk fibre to absorb a large amount of energy before breaking (

toughness In materials science and metallurgy, toughness is the ability of a material to absorb energy and plastically deform without fracturing.area under a stress-strain curve). Mechanical Properties of Spider Silk

Strength and toughness are distinct quantities. Weight for weight, silk is stronger than steel, but not as strong as Kevlar. Spider silk is, however, tougher than both. The variability of spider silk fibre mechanical properties is related to their degree of molecular alignment. Mechanical properties also depend on ambient conditions, i.e. humidity and temperature.

Young's modulus

Young's modulus Young's modulus (or the Young modulus) is a mechanical property of solid materials that measures the tensile or compressive stiffness when the force is applied lengthwise. It is the modulus of elasticity for tension or axial compression. Youn ...

is the resistance to deformation elastically along the tensile force direction. Unlike steel or Kevlar which are stiff, spider silk is ductile and elastic, having lower Young's modulus. According to Spider Silkome Database, ''Ariadna lateralis'' silk has the highest Young's modulus with 37 GPa, compared to 208 GPa for steel and 112 GPa for Kevlar.

Tensile strength

A dragline silk's

is comparable to that of high-grade alloy

steel Steel is an alloy of iron and carbon that demonstrates improved mechanical properties compared to the pure form of iron. Due to steel's high Young's modulus, elastic modulus, Yield (engineering), yield strength, Fracture, fracture strength a ...

(450−2000 MPa), and about half as strong as aramid filaments, such as Twaron or Kevlar (3000 MPa). According to Spider Silkome Database, ''Clubiona vigil'' silk has the highest tensile strength.

Density

Consisting of mainly protein, silks are about a sixth of the density of steel (1.3 g/cm³). As a result, a strand long enough to circle the Earth would weigh about . (Spider dragline silk has a tensile strength of roughly 1.3 GPa. The tensile strength listed for steel might be slightly highere.g. 1.65 GPa, but spider silk is a much less dense material, so that a given weight of spider silk is five times as strong as the same weight of steel.)

Energy density

The

energy density In physics, energy density is the quotient between the amount of energy stored in a given system or contained in a given region of space and the volume of the system or region considered. Often only the ''useful'' or extractable energy is measure ...

of dragline spider silk is roughly .

Ductility

Silks are ductile, with some able to stretch up to five times their relaxed length without breaking.

Toughness

The combination of strength and ductility gives dragline silks a high

toughness In materials science and metallurgy, toughness is the ability of a material to absorb energy and plastically deform without fracturing.polyaramid (aromatic nylon) filaments, which themselves are benchmarks of modern polymer fibre technology". According to Spider Silkome Database, ''Araneus ishisawai'' silk is the toughest.

Elongation at break

Elongation at break compares initial object length to final length at break. According to Spider Silkome Database, ''Caerostris darwini'' silk has the highest strain at break for any spider silk, breaking at 65% extension.

Temperature

While unlikely to be relevant in nature, dragline silks can hold their strength below -40 °C (-40 °F) and up to 220 °C (428 °F). As occurs in many materials, spider silk fibres undergo a

glass transition The glass–liquid transition, or glass transition, is the gradual and Reversible reaction, reversible transition in amorphous solid, amorphous materials (or in amorphous regions within Crystallinity, semicrystalline materials) from a hard and rel ...

. The glass-transition temperature depends on humidity, as water is a plasticiser for spider silk.

Supercontraction

When exposed to water, dragline silks undergo supercontraction, shrinking up to 50% in length and behaving like a weak rubber under tension. Many hypotheses have attempted to explain its use in nature, most popularly to re-tension webs built in the night using the morning dew.

Highest-performance

The toughest known spider silk is produced by the species Darwin's bark spider (''Caerostris darwini''): "The toughness of forcibly silked fibers averages 350 MJ/m³, with some samples reaching 520 MJ/m³. Thus, ''C. darwini'' silk is more than twice as tough as any previously described silk and over 10 times tougher than Kevlar".

Adhesive

Silk fibre is a two-compound pyriform secretion, spun into patterns (called "attachment discs") using a minimum of silk substrate. The pyriform threads

polymer A polymer () is a chemical substance, substance or material that consists of very large molecules, or macromolecules, that are constituted by many repeat unit, repeating subunits derived from one or more species of monomers. Due to their br ...

ise under ambient conditions, become functional immediately, and are usable indefinitely, remaining biodegradable, versatile and compatible with other materials in the environment. The adhesive and durability properties of the attachment disc are controlled by functions within the spinnerets. Some adhesive properties of the silk resemble glue, consisting of microfibrils and

lipid Lipids are a broad group of organic compounds which include fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include storing ...

enclosures.

Uses

All spiders produce silks, and a single spider can produce up to seven different types of silk for different uses. This is in contrast to insect silks, where an individual usually only produces a single type. Spiders use silks in many ways, in accord with the silk's properties. As spiders have evolved, so has their silks' complexity and uses, for example from primitive tube webs 300–400 million years ago to complex orb webs 110 million years ago.

Silk types

Meeting the specification for all these ecological uses requires different types of silk presenting different properties, as either a fibre, a structure of fibres, or a globule. These types include glues and fibres. Some types of fibres are used for structural support, others for protective structures. Some can absorb energy effectively, whereas others transmit vibration efficiently. These silk types are produced in different glands; so the silk from a particular gland can be linked to its use. Many species have different glands to produce silk with different properties for different purposes, including housing,

construction, defence, capturing and detaining

prey Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not ki ...

, egg protection, and mobility (fine "gossamer" thread for ballooning, or for a strand allowing the spider to drop down as silk is extruded). Spider cocoon-Kadavoor-2015-08-22-001

Synthesis and fibre spinning

Silk production differs in an important aspect from that of most other fibrous biomaterials. It is pulled on demand from a precursor out of specialised glands, rather than continuously grown like plant cell walls. The spinning process occurs when a fibre is pulled away from the body of a spider, whether by the spider's legs, by the spider's falling under its own weight, or by any other method. The term "spinning" is misleading because no rotation occurs. It comes from analogy to the textile spinning wheels. Silk production is a pultrusion, similar to extrusion, with the subtlety that the force is induced by pulling at the finished fibre rather than squeezing it out of a reservoir. The fibre is pulled through (possibly multiple) silk

gland A gland is a Cell (biology), cell or an Organ (biology), organ in an animal's body that produces and secretes different substances that the organism needs, either into the bloodstream or into a body cavity or outer surface. A gland may also funct ...

s of multiple types.

Silk gland

Schematic of the spiders spinning apparatus

The gland's visible, or external, part is termed the spinneret. Depending on the complexity of the species, spiders have two to eight spinnerets, usually in pairs. Species have varying specialised glands, ranging from a sac with an opening at one end, to the complex, multiple-section ampullate glands of the golden silk orb-weavers. Behind each spinneret on the surface of the spider lies a gland, a generalised form of which is shown in the figure. ;Gland characteristics # The leftmost section is the secretory or tail section. The walls of this section are lined with cells that secrete proteins Spidroin I and Spidroin II, the main components of this spider's dragline. These proteins are found in the form of droplets that gradually elongate to form long channels along the length of the final fibre, hypothesised to assist in preventing crack formation or self-healing. # The ampulla (storage sac) is next. This stores and maintains the gel-like unspun silk dope. In addition, it secretes proteins that coat the surface of the final fibre. # The funnel rapidly reduces the large diameter of the storage sac to the small diameter of the tapering duct. # The final length is the tapering duct, the site of most of the fibre formation. This consists of a tapering tube with several tight sharp turns, a valve near the end includes a spigot from which the solid silk fibre emerges. The tube tapers hyperbolically, therefore the unspun silk is under constant elongational

shear stress Shear stress (often denoted by , Greek alphabet, Greek: tau) is the component of stress (physics), stress coplanar with a material cross section. It arises from the shear force, the component of force vector parallel to the material cross secti ...

, an important factor in fibre formation. This section is lined with cells that exchange ions, reduce the dope pH from neutral to acidic, and remove water from the fibre. Collectively, the shear stress and the ion and pH changes induce the liquid silk dope to undergo a phase transition and condense into a solid protein fibre with high molecular organisation. The spigot at the end has lips that clamp around the fibre, controlling fibre diameter and further retaining water. # Almost at the end is a valve. Though discovered some time ago, its precise purpose is still under discussion. It is believed to assist in restarting and rejoining broken fibres, acting much in the way of a helical pump, regulating the thickness of the fibre, and/or clamping the fibre as a spider falls upon it. The similarity of the silk worm's silk press and the roles each of these valves play in the silk production in these two organisms are under discussion. Throughout the process the silk appears to have a nematic texture, in a manner similar to a

liquid crystal Liquid crystal (LC) is a state of matter whose properties are between those of conventional liquids and those of solid crystals. For example, a liquid crystal can flow like a liquid, but its molecules may be oriented in a common direction as i ...

, arising in part due to the high protein concentration of silk dope (around 30% in terms of weight per volume). This allows the silk to flow through the duct as a liquid while maintaining molecular order. As an example of a complex spinning field, the spinneret apparatus of an adult '' Araneus diadematus'' (garden cross spider) consists of many glands shown below. A similar gland architecture appears in the black widow spider. * 500 pyriform glands for attachment points * 4 ampullate glands for the web frame * 300 aciniform glands for the outer lining of egg sacs, and for ensnaring prey * 4 tubuliform glands for egg sac silk * 4 aggregate glands for adhesive functions * 2 coronate glands for the thread of adhesion lines

Artificial synthesis

To artificially synthesise spider silk into fibres, two broad tasks are required. These are synthesis of the feedstock (the unspun silk dope in spiders), and synthesis of the production conditions (the funnel, valve, tapering duct, and spigot). Few strategies have produced silk that can efficiently be synthesised into fibres.

Feedstock

The molecular structure of unspun silk is both complex and long. Though this endows the fibres with desirable properties, it also complicates replication. Various organisms have been used as a basis for attempts to replicate necessary protein components. These proteins must then be extracted, purified, and then spun before their properties can be tested.

Geometry

Spider silks with comparatively simple molecular structure need complex ducts to be able to form an effective fibre. Approaches:

Syringe and needle

Feedstock is forced through a hollow needle using a syringe. Although cheap and easy to produce, gland shape and conditions are loosely approximated. Fibres created using this method may need encouragement to solidify by removing water from the fibre with chemicals such as (environmentally undesirable)

methanol Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical compound and the simplest aliphatic Alcohol (chemistry), alcohol, with the chemical formula (a methyl group linked to a hydroxyl group, often ab ...

acetone Acetone (2-propanone or dimethyl ketone) is an organic compound with the chemical formula, formula . It is the simplest and smallest ketone (). It is a colorless, highly Volatile organic compound, volatile, and flammable liquid with a charact ...

, and also may require later stretching of the fibre to achieve desirable properties.

Superhydrophobic surfaces

Placing a solution of spider silk on a superhydrophobic surface can generate sheets, particles, and nanowires of spider silk.

Sheets

Self-assembly of silk at standing liquid-gas interphases of a solution tough and strong sheets. These sheets are now explored for mimicking the basal membrane in tissue modeling.

Microfluidics

Microfluidics have the advantage of being controllable and able to test spin small volumes of unspun fibre, but setup and development costs are high. A patent has been granted and continuously spun fibres have achieved commercial use.

Electrospinning

Electrospinning is an old technique whereby a fluid is held in a container such that it flows out through capillary action. A conducting substrate is positioned below, and a difference in electrical potential is applied between the fluid and the substrate. The fluid is attracted to the substrate, and tiny fibres jump from their point of emission, the Taylor cone, to the substrate, drying as they travel. This method creates nano-scale fibres from silk dissected from organisms and regenerated silk fibroin.

Other shapes

Silk can be formed into other shapes and sizes such as spherical capsules for drug delivery, cell scaffolds and wound healing, textiles, cosmetics, coatings, and many others. Spider silk proteins can self-assemble on superhydrophobic surfaces into nanowires, as well as micron-sized circular sheets. Recombinant spider silk proteins can self-assemble at the liquid-air interface of a standing solution to form protein-permeable, strong and flexible nanomembranes that support cell proliferation. Potential applications include skin transplants, and supportive membranes in organ-on-a-chip. These nanomembranes have been used to create a static ''in-vitro'' model of a blood vessel.

Synthetic spider silk

Schematic representation of spider web structure from macro to nano scale oo 86667

Replicating the complex conditions required to produce comparable fibres has challenged research and early-stage manufacturing. Through

genetic engineering Genetic engineering, also called genetic modification or genetic manipulation, is the modification and manipulation of an organism's genes using technology. It is a set of Genetic engineering techniques, technologies used to change the genet ...

, ''E. coli'' bacteria, yeasts, plants, silkworms, and animals other than silkworms have been used to produce spider silk-like proteins, which have different characteristics than those from a spider. Extrusion of protein fibres in an aqueous environment is known as "wet-spinning". This process has produced silk fibres of diameters ranging from 10 to 60 μm, compared to diameters of 2.5–4 μm for natural spider silk. Artificial spider silks have fewer and simpler proteins than natural dragline silk, and consequently offer half the diameter, strength, and flexibility of natural dragline silk.

Research

* In March 2010, researchers from the Korea Advanced Institute of Science & Technology succeeded in making spider silk directly using ''E. coli'' modified with certain genes of the spider '' Nephila clavipes''. This approach eliminates the need to "milk" spiders. * A 556 kDa spider silk protein was manufactured from 192 repeat motifs of the ''N. clavipes'' dragline spidroin, having similar mechanical characteristics as their natural counterparts, i.e.,

(1.03 ± 0.11 GPa), modulus (13.7 ± 3.0 GPa), extensibility (18 ± 6%), and toughness (114 ± 51 MJ/m3). * AMSilk developed spidroin using bacteria. * Bolt Threads produced a recombinant spidroin using yeast, for use in apparel fibers and personal care. They produced the first commercial apparel products made of recombinant spider silk, trademarked Microsilk, demonstrated in ties and beanies. * Kraig Biocraft Laboratories used research from the Universities of

Wyoming Wyoming ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States, Western United States. It borders Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho t ...

and Notre Dame to create silkworms genetically altered to produce spider silk. * Defunct Canadian

biotechnology Biotechnology is a multidisciplinary field that involves the integration of natural sciences and Engineering Science, engineering sciences in order to achieve the application of organisms and parts thereof for products and services. Specialists ...

company Nexia produced spider silk protein in transgenic

goat The goat or domestic goat (''Capra hircus'') is a species of Caprinae, goat-antelope that is mostly kept as livestock. It was domesticated from the wild goat (''C. aegagrus'') of Southwest Asia and Eastern Europe. The goat is a member of the ...

s; the milk produced by the goats contained significant quantities of the protein, 1–2 grams of silk proteins per litre of milk. Attempts to spin the protein into a fibre similar to natural spider silk resulted in fibres with tenacities of 2–3 grams per denier. Nexia used wet spinning and squeezed the silk protein solution through small extrusion holes to simulate the spinneret, but this was not sufficient to replicate native spider silk properties. * Spiber produced a synthetic spider silk (Q/QMONOS). In partnership with Goldwin, a ski parka made from this was in testing in 2016. * Researchers from Japan's RIKEN Center constructed an artificial gland that reproduced spider silk's molecular structure. Precise microfluidic mechanisms directed proteins to self-assemble into functional fibers. The process used negative pressure to pull (rather than push) a spidroin solution through the device. The resulting fibers matched the hierarchical structure of natural fiber.

Research

Human uses

The earliest recorded attempt to weave fabric from spider silk was in 1709 by François Xavier Bon who, using a process similar to creating silkworm silk, wove silk derived spider's egg cocoons into stockings and gloves. Fifty years later

Jesuit The Society of Jesus (; abbreviation: S.J. or SJ), also known as the Jesuit Order or the Jesuits ( ; ), is a religious order (Catholic), religious order of clerics regular of pontifical right for men in the Catholic Church headquartered in Rom ...

missionary invented a reeling device for harvesting spider silk directly from spiders, allowing it to be spun into threads. Neither Bon nor Termeyer were successful in producing commercially viable quantities. The development of methods to mass-produce spider silk led to the manufacturing of military, medical, and consumer goods, such as ballistic armour, athletic footwear,

personal care Personal care products are consumer products which are applied on various external parts of the body such as skin, hair, nails, lips, external genital and anal areas, as well as teeth and mucous membrane of the oral cavity, in order to make ...

products, breast implant and

catheter In medicine, a catheter ( ) is a thin tubing (material), tube made from medical grade materials serving a broad range of functions. Catheters are medical devices that can be inserted in the body to treat diseases or perform a surgical procedure. ...

coatings, mechanical

insulin Insulin (, from Latin ''insula'', 'island') is a peptide hormone produced by beta cells of the pancreatic islets encoded in humans by the insulin (''INS)'' gene. It is the main Anabolism, anabolic hormone of the body. It regulates the metabol ...

pumps, fashion clothing, and outerwear. However, due to the difficulties in extracting and processing, the largest known piece of

cloth Textile is an umbrella term that includes various fiber-based materials, including fibers, yarns, filaments, threads, and different types of fabric. At first, the word "textiles" only referred to woven fabrics. However, weaving is n ...

made of spider silk is an textile with a golden tint made in

Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...

in 2009. Eighty-two people worked for four years to collect over one million golden orb spiders and extract silk from them. In 2012, spider silk fibres were used to create a set of violin strings.

Medicine

Peasants in the southern

Carpathian Mountains The Carpathian Mountains or Carpathians () are a range of mountains forming an arc across Central Europe and Southeast Europe. Roughly long, it is the third-longest European mountain range after the Ural Mountains, Urals at and the Scandinav ...

used to cut up tubes built by '' Atypus'' and cover wounds with the inner lining. It reportedly facilitated healing, and connected with the skin. This is believed to be due to the silk's antiseptic properties,Heimer, S. (1988). Wunderbare Welt der Spinnen. ''Urania''. p. 14 and because silk is rich in

vitamin K Vitamin K is a family of structurally similar, fat-soluble vitamers found in foods and marketed as dietary supplements. The human body requires vitamin K for post-translational modification, post-synthesis modification of certain proteins ...

, which can aid in clotting blood. '' N. clavipes'' silk was used in research concerning

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

ian

neuron A neuron (American English), neurone (British English), or nerve cell, is an membrane potential#Cell excitability, excitable cell (biology), cell that fires electric signals called action potentials across a neural network (biology), neural net ...

al regeneration.

Science and technology

Spider silk has been used as a thread for crosshairs in optical instruments such as telescopes, microscopes, and telescopic rifle sights. In 2011, silk fibres were used to generate fine diffraction patterns over N-slit interferometric signals used in optical communications. Silk has been used to create biolenses that could be used in conjunction with lasers to create high-resolution images of the inside of the human body. Silk has been used to suspend inertial confinement fusion targets during laser ignition, as it remains considerably elastic and has a high energy to break at temperatures as low as 10–20 K. In addition, it is made from "light" atomic number elements that emit no

x-ray An X-ray (also known in many languages as Röntgen radiation) is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ran ...

s during irradiation that could preheat the target, limiting the pressure differential required for fusion.

References

External links

* "The Silk Spinners", a BBC program about silk-producing animals * * * Archived a
Ghostarchive
and th
Wayback Machine
* {{DEFAULTSORT:Spider Silk Materials science Animal glandular products Polyamides Silk Spider anatomy Articles containing video clips