Spider silk

File:Structure of spider silk thread Modified.svg

Silks have a hierarchical structure. The primary structure is the amino acid sequence of its proteins (spidroin), mainly consisting of highly repetitive glycine and alanine blocks,{{cite journal |author= Hinman, M. B.|author2= Lewis, R. V.|name-list-style= amp |date= 1992 |title= Isolation of a clone encoding a second dragline silk fibroin. Nephila clavipes dragline silk is a two-protein fiber |journal= J. Biol. Chem. |volume= 267 |pages= 19320–24 |pmid= 1527052 |issue= 27|doi= 10.1016/S0021-9258(18)41777-2|doi-access= free }}{{cite journal |author= Simmons, A. H.|author2= Michal, C. A.|author3= Jelinski, L. W.|name-list-style= amp |date= 1996 |title= Molecular orientation and two-component nature of the crystalline fraction of spider dragline silk |journal= Science |volume= 271 |pages= 84–87 |doi= 10.1126/science.271.5245.84 |issue=5245 |pmid= 8539605|bibcode = 1996Sci...271...84S |s2cid= 40043335}} 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.{{cite journal |author= van Beek, J. D.|author2= Hess, S.|author3= Vollrath, F.|author4= Meier, B. H.|name-list-style= amp |date= 2002 |title= The molecular structure of spider dragline silk: Folding and orientation of the protein backbone |journal= Proc. Natl. Acad. Sci. U.S.A. |volume= 99 |pages= 10266–71 |doi= 10.1073/pnas.152162299 |issue= 16 |pmid= 12149440 |pmc= 124902|bibcode = 2002PNAS...9910266V |doi-access= free}} The interplay between the hard crystalline segments and the strained elastic semi-amorphous regions gives spider silk its extraordinary properties.{{cite journal |author= Liu, Y.|author2= Sponner, A.|author3= Porter, D.|author4= Vollrath, F. |date= 2008 |title=Proline and Processing of Spider Silks |journal=Biomacromolecules |volume=9 |pages=116–21 |doi=10.1021/bm700877g |pmid= 18052126 |issue= 1}}{{cite journal|author= Papadopoulos, P.|author2= Ene, R.|author3= Weidner, I.|author4= Kremer, F. |date= 2009 |title=Similarities in the Structural Organization of Major and Minor Ampullate Spider Silk |journal=Macromol. Rapid Commun. |volume=30 |pages=851–57 |doi=10.1002/marc.200900018|pmid= 21706668|issue= 9–10}} Various compounds other than protein are used to enhance the fibre's properties. Pyrrolidine has hygroscopic 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 acidic and thus protecting it from fungi and bacteria 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.{{cite journal |author= Termonia, Y. |date= 1994 |title= Molecular Modeling of Spider Silk Elasticity |journal= Macromolecules |volume= 27 |pages= 7378–81 |doi=10.1021/ma00103a018 |issue= 25 |bibcode = 1994MaMol..27.7378T }} 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,{{cite journal |author= Vollrath, F.|author2= Holtet, T.|author3= Thogersen, H. C.|author4= Frische, S.|name-list-style= amp |date= 1996 |title= Structural organization of spider silk |journal= Proceedings of the Royal Society B |volume= 263 |pages= 147–51 |doi=10.1098/rspb.1996.0023 |issue= 1367 |bibcode= 1996RSPSB.263..147V|s2cid= 136879037}} later visualised by AFM and TEM.{{cite journal |author= Sponner, A.|date= 2007 |title= Composition and hierarchical organization of a spider silk |journal= PLOS ONE|volume=2 |pages= e998 |doi= 10.1371/journal.pone.0000998 |issue= 10 |pmid= 17912375 |pmc= 1994588 |bibcode = 2007PLoSO...2..998S |editor1-last= Scheibel |editor1-first= Thomas |first2= Wolfram |first3= Shamci |first4= Eberhard |first5= Frank |first6= Klaus |last2= Vater, Wolfram |last3= Monajembashi, Shamci |last4= Unger, Eberhard |last5= Grosse, Frank |last6= Weisshart, Klaus |doi-access= free }} {{open access}} Sizes of the nanofibrillar structure and the crystalline and semi-crystalline regions were revealed by neutron scattering.{{cite journal |author= Sapede, D.|date= 2005 |title= Nanofibrillar structure and molecular mobility in spider dragline silk |journal= Macromolecules|volume= 34 |page= 623 |doi=10.1021/ma0507995 |bibcode = 2005MaMol..38.8447S |first2= T. |last3= Forsyth |first3= V. T. |last4= Koza |first4= M. M. |last5= Schweins |first5= R. |last6= Vollrath |first6= F. |last7= Riekel |first7= C. |issue= 20 |last2= Seydel }}

The fibres' microstructural information and macroscopic mechanical properties are related.{{cite journal |author= Plaza, G.R.|author2= Pérez-Rigueiro, J.|author3= Riekel, C.|author4= Perea, G.B.|author5= Agulló-Rueda, F.|author6= Burghammer, M.|author7= Guinea, G.V.|author8= Elices, M.|date= 2012 |title= Relationship between microstructure and mechanical properties in spider silk fibers: identification of two regimes in the microstructural changes |journal= Soft Matter |volume=8 |pages= 6015–26 |doi= 10.1039/C2SM25446H |issue= 22|bibcode= 2012SMat....8.6015P|url= https://zenodo.org/record/897750}} 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.{{Cite journal|last1=Zhao|first1=Yue|last2=Hien|first2=Khuat Thi Thu|last3=Mizutani|first3=Goro|last4=Rutt|first4=Harvey N.|date=June 2017|title=Second-order nonlinear optical microscopy of spider silk|journal=Applied Physics B|volume=123|issue=6|pages=188|arxiv=1706.03186|doi=10.1007/s00340-017-6766-z|bibcode=2017ApPhB.123..188Z|s2cid=51684427}} 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.

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 and extensibility (ductility). This enables a silk fibre to absorb a large amount of energy before breaking (toughness, the area under a stress-strain curve).

File:Mechanical Properties of Spider Silk.svg

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.{{cite journal |author= Guinea, G.V.|author2= Elices, M.|author3= Pérez-Rigueiro, J.|author4= Plaza, G.R.|name-list-style= amp |date= 2005 |title= Stretching of supercontracted fibers: a link between spinning and the variability of spider silk |journal= Journal of Experimental Biology |volume= 208 |pages= 25–30 |doi=10.1242/jeb.01344 |pmid= 15601874|issue= 1 |doi-access= |s2cid= 6964043}} Mechanical properties also depend on ambient conditions, i.e. humidity and temperature.{{cite journal |bibcode=2006JPoSB..44..994P |title=Thermo-hygro-mechanical behavior of spider dragline silk: Glassy and rubbery states |last1=Plaza |first1=Gustavo R. |last4=Elices |volume=44 |date=2006 |pages=994–99 |journal=Journal of Polymer Science Part B: Polymer Physics |doi=10.1002/polb.20751 |first2=Gustavo V. |first3=José |first4=Manuel |issue=6 |last2=Guinea |last3=Pérez-Rigueiro}}

Young's modulus 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,{{Cite journal |last1=Arakawa |first1=Kazuharu |last2=Kono |first2=Nobuaki |last3=Malay |first3=Ali D. |last4=Tateishi |first4=Ayaka |last5=Ifuku |first5=Nao |last6=Masunaga |first6=Hiroyasu |last7=Sato |first7=Ryota |last8=Tsuchiya |first8=Kousuke |last9=Ohtoshi |first9=Rintaro |last10=Pedrazzoli |first10=Daniel |last11=Shinohara |first11=Asaka |last12=Ito |first12=Yusuke |last13=Nakamura |first13=Hiroyuki |last14=Tanikawa |first14=Akio |last15=Suzuki |first15=Yuya |date=2022-10-14 |title=1000 spider silkomes: Linking sequences to silk physical properties |journal=Science Advances |language=en |volume=8 |issue=41 |pages=eabo6043 |doi=10.1126/sciadv.abo6043 |issn=2375-2548 |pmc=9555773 |pmid=36223455|bibcode=2022SciA....8O6043A }} compared to 208 GPa for steel{{Cite journal |last1=Chen |first1=Zhong |last2=Gandhi |first2=Umesh |last3=Lee |first3=Jinwoo |last4=Wagoner |first4=R. H. |date=2016-01-01 |title=Variation and consistency of Young's modulus in steel |url=https://www.sciencedirect.com/science/article/pii/S0924013615301011 |journal=Journal of Materials Processing Technology |volume=227 |pages=227–243 |doi=10.1016/j.jmatprotec.2015.08.024 |issn=0924-0136}} and 112 GPa for Kevlar.{{Cite journal |last1=Nair |first1=Anand Narayanan |last2=Sundharesan |first2=Santhosh |last3=Al Tubi |first3=Issa Saif Mohammed |date=2020-11-01 |title=Kevlar-based Composite Material and its Applications in Body Armour: A Short Literature Review |journal=IOP Conference Series: Materials Science and Engineering |volume=987 |issue=1 |pages=012003 |doi=10.1088/1757-899X/987/1/012003 |issn=1757-8981|doi-access=free |bibcode=2020MS&E..987a2003N }}

A dragline silk's tensile strength is comparable to that of high-grade alloy steel (450−2000 MPa),{{cite journal |doi=10.1007/BF00551703 |title=The strength of spider silk |date=1980 |last1=Griffiths |first1=J. R. |last2=Salanitri |first2=V. R. |journal=Journal of Materials Science |volume=15 |issue=2 |pages=491–96 |bibcode=1980JMatS..15..491G|s2cid=135628690 }}{{cite web |url=http://www.matweb.com/search/datasheettext.aspx?matguid=210fcd12132049d0a3e0cabe7d091eef |title=Overview of materials for AISI 4000 Series Steel |publisher=matweb.com |access-date=18 August 2010}} and about half as strong as aramid filaments, such as Twaron or Kevlar (3000 MPa).{{cite web |url=http://www.matweb.com/search/datasheettext.aspx?matguid=77b5205f0dcc43bb8cbe6fee7d36cbb5 |title=DuPont Kevlar 49 Aramid Fiber |publisher=matweb.com |access-date=18 August 2010}} According to Spider Silkome Database, Clubiona vigil silk has the highest tensile strength.

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 {{convert|2|kg}}. (Spider dragline silk has a tensile strength of roughly 1.3 GPa. The tensile strength listed for steel might be slightly higher{{snd}}e.g. 1.65 GPa,{{cite web |url=http://www.geocities.com/pganio/materials.html |title=Material Tensile Strength Comparison |last1=Ganio Mego |first1=Paolo |archive-url=https://web.archive.org/web/20091026041350/http://geocities.com/pganio/materials.html|archive-date=26 October 2009 |date=c. 2002|access-date=3 January 2012}}{{cite journal |bibcode=2002Natur.418..741S |title=Materials: Surprising strength of silkworm silk |last1=Shao |first1=Zhengzhong |last2=Vollrath |volume=418 |date=2002 |pages=741 |journal=Nature |doi=10.1038/418741a |pmid=12181556 |first2=F |issue=6899|s2cid=4304912 |doi-access=free }} 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.)

The energy density of dragline spider silk is roughly {{val|1.2|e=8|u=J/m3}}.{{cite journal |bibcode=2005EPJE...16..199P |title=Predicting the mechanical properties of spider silk as a model nanostructured polymer |last1=Porter |first1=D. |last3=Shao |volume=16 |date=2005 |pages=199–206 |journal=European Physical Journal E |doi=10.1140/epje/e2005-00021-2 |pmid=15729511 |first2=F. |first3=Z. |issue=2 |last2=Vollrath|s2cid=32385814 }}

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

The combination of strength and ductility gives dragline silks a high toughness (or work to fracture), which "equals that of commercial polyaramid (aromatic nylon) filaments, which themselves are benchmarks of modern polymer fibre technology".{{cite web |url=http://www.chm.bris.ac.uk/motm/spider/page2.htm |title=Spider Silk |publisher=chm.bris.ac.uk |access-date=18 August 2010}} According to Spider Silkome Database, Araneus ishisawai silk is the toughest.

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.

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).{{cite journal |doi=10.1002/adma.200400344 |title=Toughness of Spider Silk at High and Low Temperatures |date=2005 |last1=Yang |first1=Y. |last2=Chen |first2=X. |last3=Shao |first3=Z. |last4=Zhou |first4=P. |last5=Porter |first5=D. |last6=Knight |first6=D. P. |last7=Vollrath |first7=F. |journal=Advanced Materials |volume=17 |issue=1 |pages=84–88|bibcode=2005AdM....17...84Y |s2cid=136693986 }} As occurs in many materials, spider silk fibres undergo a glass transition. The glass-transition temperature depends on humidity, as water is a plasticiser for spider silk.

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.{{Citation needed|date=May 2013}}

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".{{cite journal |bibcode=2010PLoSO...511234A |title=Bioprospecting Finds the Toughest Biological Material: Extraordinary Silk from a Giant Riverine Orb Spider |last1=Agnarsson |first1=Ingi |last2=Kuntner |last3=Blackledge |volume=5 |date=2010 |page=11234 |journal=PLOS ONE|doi=10.1371/journal.pone.0011234 |editor1-last=Lalueza-Fox |editor1-first=Carles |first2=Matjaž |first3=Todd A. |issue=9 |pmid=20856804 |pmc=2939878|doi-access=free }} {{open access}}

Silk fibre is a two-compound pyriform secretion, spun into patterns (called "attachment discs") using a minimum of silk substrate.{{cite journal|pmid=25672841|year=2015|last1=Wolff|first1=J. O.|title=Spider's super-glue: Thread anchors are composite adhesives with synergistic hierarchical organization|journal=Soft Matter|volume=11|issue=12|pages=2394–403|last2=Grawe|first2=I|last3=Wirth|first3=M|last4=Karstedt|first4=A|last5=Gorb|first5=S. N.|doi=10.1039/c4sm02130d|bibcode=2015SMat...11.2394W|doi-access=free}} The pyriform threads polymerise 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.{{cite journal|pmid=23033082|year=2012|last1=Sahni|first1=V|title=Cobweb-weaving spiders produce different attachment discs for locomotion and prey capture|journal=Nature Communications|volume=3|pages=1106|last2=Harris|first2=J|last3=Blackledge|first3=T. A.|last4=Dhinojwala|first4=A|doi=10.1038/ncomms2099|bibcode=2012NatCo...3.1106S|doi-access=free}} Some adhesive properties of the silk resemble glue, consisting of microfibrils and lipid enclosures.

All spiders produce silks, and a single spider can produce up to seven different types of silk for different uses.{{cite book|author=Foelix, R. F. |title= Biology of Spiders |url=https://archive.org/details/biologyofspiders00foel_0 |url-access=registration |date= 1996 |publisher= Oxford University Press |location= Oxford; New York|page= [https://archive.org/details/biologyofspiders00foel_0/page/330 330]|isbn= 978-0-19-509594-4 }} This is in contrast to insect silks, where an individual usually only produces a single type.{{cite journal |pmid=19728833 |date=2010 |last1=Sutherland |first1=TD |last2=Young |first2=JH |last3=Weisman |first3=S |last4=Hayashi |first4=CY |last5=Merritt |first5=DJ |title=Insect silk: One name, many materials |volume=55 |pages=171–88 |doi=10.1146/annurev-ento-112408-085401 |journal=Annual Review of Entomology}} 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.{{cite book|author= Hillyard, P. |title= The Private Life of Spiders |date= 2007 |publisher= New Holland |location= London |isbn= 978-1-84537-690-1 |page= 160}}

File:Argiope picta wrapping prey 3836.jpg

File:Crab spider safety line.webm jumps with safety line, on yellow ironweed. Repeated at variable slow motion to better see silk line. Spider probably Misumessus oblongus.]]

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, web construction, defence, capturing and detaining prey, egg protection, and mobility (fine "gossamer" thread for ballooning, or for a strand allowing the spider to drop down as silk is extruded).{{cite journal |doi=10.1002/scin.2007.5591711509 |title=Taken for a spin: Scientists look to spiders for the goods on silk |date=2009 |last1=Cunningham |first1=Aimee |journal=Science News |volume=171 |issue=15 |pages=231–34}}{{cite journal |pmid=16788028 |date=2006 |last1=Blackledge |first1=TA |last2=Hayashi |first2=CY |title=Silken toolkits: Biomechanics of silk fibers spun by the orb web spider Argiope argentata (Fabricius 1775) |volume=209 |issue=Pt 13 |pages=2452–61 |doi=10.1242/jeb.02275 |journal=The Journal of Experimental Biology|doi-access= |s2cid=16044608 }}File:Spider cocoon-Kadavoor-2015-08-22-001.jpg

File:Araneus diadematus underside 1.jpg spinning its web]]

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,{{cite journal |last1=Andersson |first1=M |last2=Johansson |first2=J |last3=Rising |first3=A |year=2016 |title=Silk Spinning in Silkworms and Spiders |journal=International Journal of Molecular Sciences |volume=17 |issue=8 |pages=1290 |doi=10.3390/ijms17081290 |pmc=5000687 |pmid=27517908 |doi-access=free}} 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,{{cite journal |author= Wilson, R. S. |date= 1969 |title= control of drag-line spinning in certain spiders |journal= Am. Zool. |volume= 9 |pages= 103–|doi=10.1093/icb/9.1.103 |doi-access= free }} 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 glands of multiple types.

{{further information|Spider anatomy}}

File:Schematic of the spiders spinning apparatus.svg

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.{{cite journal |author= Dicko, C.|author2= Porter, D.|author3= Bond, J.|author4= Kenney, J. M.|author5= Vollratht, F.|name-list-style= amp |date= 2008 |title= Structural disorder in silk proteins reveals the emergence of elastomericity |journal= Biomacromolecules |volume= 9 |pages= 216–21 |doi= 10.1021/bm701069y |pmid= 18078324 |issue= 1}}

Behind each spinneret on the surface of the spider lies a gland, a generalised form of which is shown in the figure.

{{Clear}}

;Gland characteristics

File:Spider silk duct.svg. Each differently coloured section highlights a discrete section of the gland.{{cite journal |author= Lefèvre, T.|author2= Boudreault, S.|author3= Cloutier, C.|author4= Pézolet, M.|name-list-style= amp |date= 2008 |title= Conformational and orientational transformation of silk proteins in the major ampullate gland of Nephila clavipes spiders |journal= Biomacromolecules |volume= 9 |pages= 2399–407 |doi= 10.1021/bm800390j |issue= 9 |pmid= 18702545}}{{cite journal |author= Heim, M.|author2= Keerl, D.|author3= Scheibel, T.|name-list-style= amp |date= 2009 |title= Spider Silk: From Soluble Protein to Extraordinary Fiber |journal= Angewandte Chemie International Edition |volume= 48 |pages= 3584–96 |doi= 10.1002/anie.200803341 |pmid= 19212993|issue= 20}}]]

1. 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.{{cite journal |author= Heinhorst, S.|author2= Cannon, G. |date= 2002 |title= Nature: Self-Healing Polymers and Other Improved Materials |journal=J. Chem. Educ. |volume= 79 |issue= 1 |page= 10 |doi=10.1021/ed079p10|bibcode = 2002JChEd..79...10H }}
2. 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.{{cite journal |author=Vollrath, F.|author2=Knight, D. P.|name-list-style=amp |date=2001 |title=Liquid crystalline spinning of spider silk |journal= Nature |volume= 410 |pages= 541–48 |doi=10.1038/35069000 |issue=6828 |pmid=11279484 |bibcode=2001Natur.410..541V|s2cid=205015549}}
3. The funnel rapidly reduces the large diameter of the storage sac to the small diameter of the tapering duct.
4. 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, 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.{{Cite journal|last1=Knight|first1=D. P.|last2=Vollrath|first2=F.|date=2001-04-01|title=Changes in element composition along the spinning duct in a Nephila spider|journal=Die Naturwissenschaften|volume=88|issue=4|pages=179–82|issn=0028-1042|pmid=11480706|doi=10.1007/s001140100220|bibcode=2001NW.....88..179K|s2cid=26097179}} 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.
5. 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,{{cite journal |author= Vollrath, F.|author2= Knight, D. P.|name-list-style= amp |date= 1998 |title= Structure and function of the silk production pathway in spider Nephila edulis |journal= Int J Biol Macromol |volume= 24 |pages= 243–49 |doi=10.1016/S0141-8130(98)00095-6 |issue= 2–3 |pmid= 10342771}} 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.{{cite journal |author= Wilson, R. S. |date= 1962 |title= The Control of Dragline Spinning in the Garden Spider |journal= Quarterly Journal of Microscopical Science |volume= 103 |pages= 557–71 }} 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,{{cite journal |author= Magoshi, J.|author2= Magoshi, Y.|author3= Nakamura, S.|name-list-style= amp |date= 1985 |title= Physical properties and structure of silk: 9. Liquid crystal formation of silk fibroin |journal= Polym. Commun. |volume= 26 |pages= 60–61 }} in a manner similar to a liquid crystal, arising in part due to the high protein concentration of silk dope (around 30% in terms of weight per volume).{{Cite journal|last1=Chen|first1=Xin|last2=Knight|first2=David P.|last3=Vollrath|first3=Fritz|date=2002-07-01|title=Rheological characterization of nephila spidroin solution|journal=Biomacromolecules|volume=3|issue=4|pages=644–48|issn=1525-7797|pmid=12099805|doi=10.1021/bm0156126}} 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.{{cite journal|pmc=3341101|year=2011|last1=Jeffery|first1=F|title=Microdissection of Black Widow Spider Silk-producing Glands|journal=Journal of Visualized Experiments|issue=47|pages=2382|last2=La Mattina|first2=C|last3=Tuton-Blasingame|first3=T|last4=Hsia|first4=Y|last5=Gnesa|first5=E|last6=Zhao|first6=L|last7=Franz|first7=A|last8=Vierra|first8=C|doi=10.3791/2382|pmid=21248709}}

• 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

File:Artificial Spider Silk Strand.JPG

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.

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.

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

Feedstock is forced through a hollow needle using a syringe.{{cite journal |author= Lazaris, A.|date= 2002 |title= Spider silk fibers spun from soluble recombinant silk produced in mammalian cells |journal= Science |volume= 295 |pages= 472–76 |doi=10.1126/science.1065780 |pmid=11799236|bibcode = 2002Sci...295..472L |issue= 5554 |first2= S |first3= Y |first4= JF |first5= F |first6= N |first7= EA |first8= JW |first9= CN |last2= Arcidiacono, S |last3= Huang, Y |last4= Zhou, J. F. |last5= Duguay, F |last6= Chretien, N |last7= Welsh, E. A. |last8= Soares, J. W. |last9= Karatzas, C. N. |s2cid= 9260156 }}{{cite journal |author= Seidel, A.|date= 2000 |title= Regenerated spider silk: Processing, properties, and structure |journal= Macromolecules |volume= 33 |pages= 775–80 |doi=10.1021/ma990893j |bibcode = 2000MaMol..33..775S |first2= Oskar |last3= Calve |first3= Sarah |last4= Adaska |first4= Jason |last5= Ji |first5= Gending |last6= Yang |first6= Zhitong |last7= Grubb |first7= David |last8= Zax |first8= David B. |last9= Jelinski |first9= Lynn W. |issue= 3 |last2= Liivak }}

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{{cite journal |author= Arcidiacono, S.|date= 2002 |title= Aqueous processing and fiber spinning of recombinant spider silks |journal= Macromolecules |volume= 35 |pages= 1262–66 |doi=10.1021/ma011471o |bibcode = 2002MaMol..35.1262A |first2= Charlene M. |last3= Butler |first3= Michelle |last4= Welsh |first4= Elizabeth |last5= Soares |first5= Jason W. |last6= Allen |first6= Alfred |last7= Ziegler |first7= David |last8= Laue |first8= Thomas |last9= Chase |first9= Susan |issue= 4 |last2= Mello }} or acetone, and also may require later stretching of the fibre to achieve desirable properties.{{cite journal |author= Xia, X. X.|date= 2010 |title= Native-sized recombinant spider silk protein produced in metabolically engineered Escherichia coli results in a strong fiber |journal= Proceedings of the National Academy of Sciences of the United States of America |volume= 107 |pages= 14,059–63 |doi= 10.1073/pnas.1003366107|bibcode = 2010PNAS..10714059X |issue= 32 |display-authors=etal |pmid=20660779 |pmc=2922564|doi-access= free }}

Placing a solution of spider silk on a superhydrophobic surface can generate sheets, particles, and nanowires of spider silk.{{cite journal | author1= Gustafsson, L. | author2= Jansson, R. | author3= Hedhammar, M. | author4= van der Wijngaart, W. | date= 2018 |title= Structuring of Functional Spider Silk Wires, Coatings, and Sheets by Self-Assembly on Superhydrophobic Pillar Surfaces |journal= Advanced Materials|volume= 30 |issue= 3 |doi= 10.1002/adma.201704325 | pmid= 29205540 | bibcode= 2018AdM....3004325G | s2cid= 205283504 }}{{cite journal | author1= Gustafsson, L. | author2= Kvick, M. | author3= Åstrand, C. | author4= Ponsteen, N. | author5= Dorka, N. | author6= Hegrová, V. | author7= Svanberg, S. | author8= Horák, J. | author9= Jansson, R. | author10= Hedhammar, M. | author11= van der Wijngaart, W. | date= 2023 |title= Scalable Production of Monodisperse Bioactive Spider Silk Nanowires |journal= Macromolecular Bioscience | volume= 23 | issue= 4 | pages= e2200450 | doi= 10.1002/mabi.202200450| pmid= 36662774 | s2cid= 256032679 | doi-access= free }}

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.{{Citation | vauthors=Gustafsson L, Tasiopoulos CP, Jansson R, Kvick M, Duursma T, Gasser TC, Wijngaart W, Hedhammar M | year=2020 | title=Recombinant Spider Silk Forms Tough and Elastic Nanomembranes that are Protein-Permeable and Support Cell Attachment and Growth |journal = Advanced Functional Materials | volume=30 | issue=40 | doi=10.1002/adfm.202002982 | s2cid=225398425 | doi-access=free }}{{Citation | vauthors=Tasiopoulos CP, Gustafsson L, Wijngaart W, van der Hedhammar M | year=2021 | title=Fibrillar Nanomembranes of Recombinant Spider Silk Protein Support Cell Co-culture in an In Vitro Blood Vessel Wall Model |journal= ACS Biomaterials Science & Engineering| volume=7 | issue=7 | pages=3332–3339 | doi=10.1021/acsbiomaterials.1c00612 | pmid=34169711 | pmc=8290846 | url=http://dx.doi.org/10.1021/acsbiomaterials.1c00612}}

Microfluidics have the advantage of being controllable and able to test spin small volumes of unspun fibre,{{cite journal |author= Kinahan, M. E.|date= 2011 |title= Tunable Silk: Using Microfluidics to Fabricate Silk Fibers with Controllable Properties |journal= Biomacromolecules |volume= 12 |pages= 1504–11 |doi= 10.1021/bm1014624 |issue= 5 |pmid= 21438624 |pmc= 3305786|display-authors=etal}}{{cite journal |author= Rammensee, S.|author2= Slotta, U.|author3= Scheibel, T.|author4= Bausch, A. R.|name-list-style= amp |date= 2008 |title= Assembly mechanism of recombinant spider silk proteins (microfluidic) |journal= Proceedings of the National Academy of Sciences of the United States of America |volume= 105 |pages= 6590–95 |doi= 10.1073/pnas.0709246105|bibcode = 2008PNAS..105.6590R |issue= 18 |pmid= 18445655 |pmc= 2373321 |doi-access= free}} but setup and development costs are high. A patent has been granted and continuously spun fibres have achieved commercial use.[http://www.spintec-engineering.de/spintec-engineering.de/Home.html Spintec Engineering GmbH] {{in lang|de}}

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.{{Cn|date=January 2024}}

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.{{cite journal |author= Eisoldt, L.|author2= Smith, A.|author3= Scheibel, T.|name-list-style= amp |date= 2011 |title= Decoding the secrets of spider silk |journal= Mater. Today |volume= 14 |pages= 80–86 |doi= 10.1016/s1369-7021(11)70057-8 |issue= 3|doi-access= free }}{{cite journal |author= Gustafsson, L.|author2= Jansson, R.|author3= Hedhammar, M.|author4= van der Wijngaart, W.|name-list-style= amp |date= 2018 |title= Structuring of Functional Spider Silk Wires, Coatings, and Sheets by Self-Assembly on Superhydrophobic Pillar Surfaces |journal= Adv. Mater. |volume= 30 |doi= 10.1002/adma.201704325 |pmid= 29205540|issue= 3|pages= 1704325|bibcode= 2018AdM....3004325G|s2cid= 205283504}} 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.{{cite journal |last1=Gustafsson |first1=Linnea |last2=Panagiotis Tasiopoulos |first2=Christos |last3=Jansson |first3=Ronnie |last4=Kvick |first4=Mathias |last5=Duursma |first5=Thijs |last6=Gasser |first6=Thomas Christian |last7=van der Wijngaart |first7=Wouter |last8=Hedhammar |first8=My |title=Recombinant Spider Silk Forms Tough and Elastic Nanomembranes that are Protein-Permeable and Support Cell Attachment and Growth |journal=Advanced Functional Materials |date=16 August 2020 |volume=30 |issue=40 |pages=2002982 |doi=10.1002/adfm.202002982 |doi-access=free }} These nanomembranes have been used to create a static in-vitro model of a blood vessel.{{Cite journal|last1=Tasiopoulos|first1=Christos Panagiotis|last2=Gustafsson|first2=Linnea|last3=van der Wijngaart|first3=Wouter|last4=Hedhammar|first4=My|date=2021-06-25|title=Fibrillar Nanomembranes of Recombinant Spider Silk Protein Support Cell Co-culture in an in Vitro Blood Vessel Wall Model|journal=ACS Biomaterials Science & Engineering|volume=7|issue=7|pages=3332–3339|doi=10.1021/acsbiomaterials.1c00612|pmid=34169711|pmc=8290846|doi-access=free}}

File:Schematic representation of spider web structure from macro to nano scale oo 86667.png

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

• 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.{{cite journal |bibcode=2010PNAS..10714059X |first1=Xiao-Xia |last1=Xia |first2=Zhi-Gang |last2=Qian |first3=Chang Seok |last3=Ki |first4=Young Hwan |last4=Park |first5=David L. |last5=Kaplan |first6=Sang Yup |last6=Lee |title=Native-sized recombinant spider silk protein produced in metabolically engineered Escherichia coli results in a strong fiber |jstor=25708855 |volume=107 |date=2010 |pages=14059–63 |journal=Proceedings of the National Academy of Sciences |doi=10.1073/pnas.1003366107 |issue=32 |pmid=20660779 |pmc=2922564|doi-access=free }}
• 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., tensile strength (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.{{cite web|url=http://www.kijkmagazine.nl/artikel/spinnendraad/|title=Draadkracht: spindoctors maken supersterk nepweb|date=21 April 2012|publisher=KIJK|language=nl|trans-title=Wire strength: spin doctors make super strong fake cobweb|access-date=15 October 2014}}
• 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.{{Cite web|url=https://boltthreads.com/technology/microsilk|title = Bolt Threads – Microsilk}}{{Cite web|url=https://boltthreads.com/technology/silk-protein|title = Bolt Threads – B-silk protein}}
• Kraig Biocraft Laboratories used research from the Universities of Wyoming and Notre Dame to create silkworms genetically altered to produce spider silk.{{cite press release |title=University of Notre Dame and Kraig Biocraft Laboratories Create Artificial Spider Silk Breakthrough |url=http://www.kraiglabs.com/Spider-silk-created-9-29-2010.htm |publisher=Kraig Biocraft Laboratories |date=29 September 2010 |access-date=3 January 2012 |archive-date=25 May 2011 |archive-url=https://web.archive.org/web/20110525013634/http://www.kraiglabs.com/Spider-silk-created-9-29-2010.htm |url-status=dead }}{{cite press release |title=Fraser Research Publicly Announced at Press Conference |url=http://science.nd.edu/research/profiles/fraser_silkworms.htm |archive-url=https://web.archive.org/web/20101010183518/http://science.nd.edu/research/profiles/fraser_silkworms.htm |archive-date=10 October 2010 |publisher=University of Notre Dame |date=1 October 2010 |access-date=3 January 2012}}
• Defunct Canadian biotechnology company Nexia produced spider silk protein in transgenic goats; 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.{{cite journal |last1=Kluge |first1=Jonathan A. |last2=Rabotyagova |first2=Olena |last3=Leisk |first3=Gary G. |last4=Kaplan |first4=David L. |date=May 2008 |title=Spider silks and their applications |journal=Trends in Biotechnology |volume=26 |issue=5 |pages=244–51 |doi=10.1016/j.tibtech.2008.02.006 |pmid=18367277 }} 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.{{cite journal |last1= Scheibel |first1=Thomas |date=November 2004 |title=Spider silks: recombinant synthesis, assembly, spinning, and engineering of synthetic proteins |journal=Microbial Cell Factories |volume=3 |page=14 |doi=10.1186/1475-2859-3-14 |pmid=15546497 |pmc=534800 |issue=1 |doi-access=free }}
• Spiber produced a synthetic spider silk (Q/QMONOS). In partnership with Goldwin, a ski parka made from this was in testing in 2016.{{Cite web|url=https://www.goldwin-sports.com/us/feature/goldwinskijacket/|title = Goldwin x Spiber Ski Jacket}}{{Cite web|url=https://qz.com/708298/synthetic-spider-silk-could-be-the-biggest-technological-advance-in-clothing-since-nylon/|title=Synthetic spider silk could be the biggest technological advance in clothing since nylon|first=Marc|last=Bain|website=Quartz |date=July 3, 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.{{Cite web |last=Thompson |first=Bronwyn |date=January 22, 2024 |title=Artificial spider gland spins scalable spider silk just like nature |url=https://newatlas.com/materials/artificial-gland-spins-spider-silk-rapidly-repeatedly/ |access-date=2024-02-08 |website=New Atlas |language=en-US}}

File:Spider silk cape.jpg silk{{cite news|url=https://www.theguardian.com/artanddesign/2012/jan/24/spider-silk-cape-show|title=Spider silk cape goes on show at V&A|author=Maev Kennedy|newspaper=the Guardian|date=2012-01-24}}]]

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 missionary {{ill|Ramón M. Termeyer|pl|Ramón María Termeyer}} 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.{{Cite journal |last=Morgan |first=Eleanor |date=2016 |title=Sticky Layers and Shimmering Weaves: A Study of Two Human Uses of Spider Silk |journal=Journal of Design History |language=en |volume=29 |issue=1 |pages=8–23 |doi=10.1093/jdh/epv019 |issn=0952-4649 |jstor=43831651|doi-access=free }}

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 products, breast implant and catheter coatings, mechanical insulin pumps, fashion clothing, and outerwear.{{cite web|url=https://www.science.org/content/article/spinning-spider-silk-startup-gold|title=Spinning spider silk into startup gold|publisher=Science Magazine, American Association for the Advancement of Science|author=Service, Robert F.|date=18 October 2017|access-date=26 November 2017}} However, due to the difficulties in extracting and processing, the largest known piece of cloth made of spider silk is an {{convert|11|by|4|ft|adj=on}} textile with a golden tint made in Madagascar in 2009.{{Cite web|title=V&A · Golden spider silk|url=https://www.vam.ac.uk/articles/golden-spider-silk|access-date=2022-01-07|website=Victoria and Albert Museum|language=en}} Eighty-two people worked for four years to collect over one million golden orb spiders and extract silk from them.{{cite magazine|title=1 Million Spiders Make Golden Silk for Rare Cloth|url=https://www.wired.com/wiredscience/2009/09/spider-silk/ | magazine=Wired | first=Hadley|last=Leggett|date=23 September 2009}} In 2012, spider silk fibres were used to create a set of violin strings.{{cite journal |doi=10.1103/PhysRevLett.108.154301 |pmid=22587257 |title=Spider Silk Violin Strings with a Unique Packing Structure Generate a Soft and Profound Timbre |date=2012 |last1=Osaki |first1=Shigeyoshi |journal=Physical Review Letters |volume=108 |issue=15 |pages=154301 |bibcode=2012PhRvL.108o4301O}}

Peasants in the southern Carpathian Mountains 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, which can aid in clotting blood.{{cite journal |first1=Robert R. |last1=Jackson |date=1974 |title=Effects of D-Amphetamine Sulfate and Diazepam on Thread Connection Fine Structure in a Spider's Web |journal=Journal of Arachnology |volume=2 |issue=1 |pages=37–41 |jstor=3704994}}{{Verify quote|date=June 2018}} N. clavipes silk was used in research concerning mammalian neuronal regeneration.{{cite journal |doi=10.1111/j.1582-4934.2006.tb00436.x |pmid=16989736 |pmc=3933158 |first1=Christina |last1=Allmeling |first2=Andreas |last2=Jokuszies |first3=Kerstin |last3=Reimers |first4=Susanne |last4=Kall |first5=Peter M. |last5=Vogt |date=2006 |title=Use of spider silk fibres as an innovative material in a biocompatible artificial nerve conduit |volume=10 |issue=3 |pages=770–77 |journal=Journal of Cellular and Molecular Medicine}}

Spider silk has been used as a thread for crosshairs in optical instruments such as telescopes, microscopes,Berenbaum, May R., Field Notes – Spin Control, The Sciences, The New York Academy of Sciences, September/October 1995 and telescopic rifle sights.{{cite book|url=https://books.google.com/books?id=WyYDAAAAMBAJ&q=%22telescopic+sight%22+spider+silk&pg=RA1-PA216 |title=Example of use of spider silk for telescopic rifle sights |year=1955|access-date=24 August 2011|publisher=Bonnier Corporation }} In 2011, silk fibres were used to generate fine diffraction patterns over N-slit interferometric signals used in optical communications.{{cite journal |bibcode=2011JOpt...13c5710D |title=N-slit interferometer for secure free-space optical communications: 527 m intra interferometric path length |author=Duarte F. J. |last5=Varmette |volume=13 |date=2011 |pages=5710 |journal=Journal of Optics |doi=10.1088/2040-8978/13/3/035710 |first2=T S |first3=A M |first4=W E |first5=P G |issue=3 |last2=Taylor |last3=Black |last4=Davenport |s2cid=6086533 |author-link1=F. J. Duarte }} 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.{{Cite news |url=https://www.sciencefocus.com/news/spider-silk-used-to-create-lenses-for-imaging-human-tissue/ |title=Spider silk used to create lenses for imaging human tissue |work=BBC Science Focus |first=Jason |last=Goodyer |date=July 5, 2020}}

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-rays during irradiation that could preheat the target, limiting the pressure differential required for fusion.{{Cite web |url=http://www.lle.rochester.edu/media/publications/documents/theses/Bonino.pdf |title=Material Properties of Spider Silk |first=Mark J. |last=Bonino}}

{{Reflist}}

{{Commons category}}

• "The Silk Spinners", a BBC program about silk-producing animals
• {{cite journal|last1=Meadows|first1=Robin|title=How Spiders Spin Silk|journal=PLOS Biology|date=5 August 2014|volume=12|issue=8|pages=e1001922|doi=10.1371/journal.pbio.1001922|pmid=25093404|pmc=4122354 |doi-access=free }}
• {{Cite web|url=https://singularityhub.com/2019/04/11/the-tangled-web-of-turning-spider-silk-into-a-super-material/|title=The Tangled Web of Turning Spider Silk into a Super Material|last=Rejcek|first=Peter|date=2019-04-11|website=Singularity Hub|language=en-US|access-date=2019-04-24}}
• Archived at [https://ghostarchive.org/varchive/youtube/20211211/Fv1qq6ypiTk Ghostarchive]{{cbignore}} and the [https://web.archive.org/web/20190811183123/https://www.youtube.com/watch?time_continue=22&v=Fv1qq6ypiTk Wayback Machine]{{cbignore}}: {{Cite web|url=https://www.youtube.com/watch?v=Fv1qq6ypiTk|title=How was it made? Golden spider silk|last=Victoria and Albert Museum|date=2019-07-29|website=YouTube|language=en-US|access-date=2020-08-08}}{{cbignore}}
• {{Cite web|date=2021-07-21|title=Synthetic spider silk stronger and tougher than the real thing|url=https://newatlas.com/materials/synthetic-spider-silk-stronger-tougher/|access-date=2021-07-21|website=New Atlas|language=en-US}}

{{Spider nav}}

{{Fibers}}

{{DEFAULTSORT:Spider Silk}}

Category:Materials science

Category:Animal glandular products

Category:Polyamides

Category:Silk

Category:Spider anatomy

Category:Articles containing video clips