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Silk is a
natural Nature, in the broadest sense, is the physical world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. Although humans are p ...
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
fiber Fiber or fibre (from la, fibra, links=no) is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate ...
, some forms of which can be
woven Woven fabric is any textile formed by weaving. Woven fabrics are often created on a loom, and made of many threads woven on a warp and a weft. Technically, a woven fabric is any fabric made by interlacing two or more threads at right angles to on ...
into
textile Textile is an umbrella term that includes various fiber-based materials, including fibers, yarns, filaments, threads, different fabric types, etc. At first, the word "textiles" only referred to woven fabrics. However, weaving is not the ...
s. The protein fiber of silk is composed mainly of
fibroin Fibroin is an insoluble protein present in silk produced by numerous insects, such as the larvae of ''Bombyx mori'', and other moth genera such as '' Antheraea'', '' Cricula'', '' Samia'' and '' Gonometa''. Silk in its raw state consists of tw ...
and is produced by certain insect
larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...
e to form cocoons. The best-known silk is obtained from the cocoons of the larvae of the mulberry silkworm ''
Bombyx mori The domestic silk moth (''Bombyx mori''), is an insect from the moth family Bombycidae. It is the closest relative of ''Bombyx mandarina'', the wild silk moth. The silkworm is the larva or caterpillar of a silk moth. It is an economically imp ...
'' reared in captivity (
sericulture Sericulture, or silk farming, is the cultivation of silkworms to produce silk. Although there are several commercial species of silkworms, ''Bombyx mori'' (the caterpillar of the domestic silkmoth) is the most widely used and intensively studie ...
). The shimmering appearance of silk is due to the triangular
prism Prism usually refers to: * Prism (optics), a transparent optical component with flat surfaces that refract light * Prism (geometry), a kind of polyhedron Prism may also refer to: Science and mathematics * Prism (geology), a type of sedimentary ...
-like structure of the silk fibre, which allows silk cloth to refract incoming light at different
angle In Euclidean geometry, an angle is the figure formed by two Ray (geometry), rays, called the ''Side (plane geometry), sides'' of the angle, sharing a common endpoint, called the ''vertex (geometry), vertex'' of the angle. Angles formed by two ...
s, thus producing different colors. Silk is produced by several insects; but, generally, only the silk of moth caterpillars has been used for textile manufacturing. There has been some research into other types of silk, which differ at the molecular level. Silk is mainly produced by the larvae of insects undergoing
complete metamorphosis Holometabolism, also called complete metamorphosis, is a form of insect development which includes four life stages: egg, larva, pupa, and imago (or adult). Holometabolism is a synapomorphic trait of all insects in the superorder Endopterygo ...
, but some insects, such as
webspinner The order Embioptera, commonly known as webspinners or footspinners, are a small group of mostly tropical and subtropical insects, classified under the subclass Pterygota. The order has also been called Embiodea or Embiidina. More than 400 s ...
s and raspy crickets, produce silk throughout their lives. Silk production also occurs in
hymenoptera Hymenoptera is a large order (biology), order of insects, comprising the sawfly, sawflies, wasps, bees, and ants. Over 150,000 living species of Hymenoptera have been described, in addition to over 2,000 extinct ones. Many of the species are Par ...
( bees,
wasp A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder. Th ...
s, and
ant Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of 22 ...
s),
silverfish The silverfish (''Lepisma saccharinum'') is a species of small, primitive, wingless insect in the order Zygentoma (formerly Thysanura). Its common name derives from the insect's silvery light grey colour, combined with the fish-like appearance ...
,
mayflies Mayflies (also known as shadflies or fishflies in Canada and the upper Midwestern United States, as Canadian soldiers in the American Great Lakes region, and as up-winged flies in the United Kingdom) are aquatic insects belonging to the order ...
,
thrips Thrips ( order Thysanoptera) are minute (mostly long or less), slender insects with fringed wings and unique asymmetrical mouthparts. Different thrips species feed mostly on plants by puncturing and sucking up the contents, although a few are ...
,
leafhopper A leafhopper is the common name for any species from the family Cicadellidae. These minute insects, colloquially known as hoppers, are plant feeders that suck plant sap from grass, shrubs, or trees. Their hind legs are modified for jumping, and a ...
s,
beetle Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...
s,
lacewing The insect order Neuroptera, or net-winged insects, includes the lacewings, mantidflies, antlions, and their relatives. The order consists of some 6,000 species. Neuroptera can be grouped together with the Megaloptera and Raphidioptera in t ...
s,
flea Flea, the common name for the order Siphonaptera, includes 2,500 species of small flightless insects that live as external parasites of mammals and birds. Fleas live by ingesting the blood of their hosts. Adult fleas grow to about long, a ...
s,
flies Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced ...
, and
midge A midge is any small fly, including species in several families of non-mosquito Nematoceran Diptera. Midges are found (seasonally or otherwise) on practically every land area outside permanently arid deserts and the frigid zones. Some mid ...
s. Other types of
arthropod Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...
s produce silk, most notably various
arachnid Arachnida () is a class of joint-legged invertebrate animals (arthropods), in the subphylum Chelicerata. Arachnida includes, among others, spiders, scorpions, ticks, mites, pseudoscorpions, harvestmen, camel spiders, whip spiders and vinegaroon ...
s, such as
spider Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species ...
s.


Etymology

The word silk comes from ang, sioloc, from grc, σηρικός, translit=sērikós, "silken", ultimately from the Chinese word "sī" and other Asian sources—compare
Mandarin Mandarin or The Mandarin may refer to: Language * Mandarin Chinese, branch of Chinese originally spoken in northern parts of the country ** Standard Chinese or Modern Standard Mandarin, the official language of China ** Taiwanese Mandarin, Stand ...
"silk", Manchurian , Mongolian .


History

The production of silk originated in
China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
in the
Neolithic The Neolithic period, or New Stone Age, is an Old World archaeological period and the final division of the Stone Age. It saw the Neolithic Revolution, a wide-ranging set of developments that appear to have arisen independently in several parts ...
period, although it would eventually reach other places of the world ( culture, 4th millennium BC). Silk production remained confined to China until the
Silk Road The Silk Road () was a network of Eurasian trade routes active from the second century BCE until the mid-15th century. Spanning over 6,400 kilometers (4,000 miles), it played a central role in facilitating economic, cultural, political, and reli ...
opened at some point during the latter part of the 1st millennium BC, though China maintained its virtual
monopoly A monopoly (from Greek language, Greek el, μόνος, mónos, single, alone, label=none and el, πωλεῖν, pōleîn, to sell, label=none), as described by Irving Fisher, is a market with the "absence of competition", creating a situati ...
over
silk production Sericulture, or silk farming, is the cultivation of silkworms to produce silk. Although there are several commercial species of silkworms, ''Bombyx mori'' (the caterpillar of the domestic silkmoth) is the most widely used and intensively studie ...
for another thousand years.


Wild silk

Several kinds of wild silk, produced by
caterpillar Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths). As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder Sym ...
s other than the
mulberry ''Morus'', a genus of flowering plants in the family Moraceae, consists of diverse species of deciduous trees commonly known as mulberries, growing wild and under cultivation in many temperate world regions. Generally, the genus has 64 identif ...
silkworm, have been known and spun in
China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
,
South Asia South Asia is the southern subregion of Asia, which is defined in both geographical and ethno-cultural terms. The region consists of the countries of Afghanistan, Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan, and Sri Lanka.;;;;;;;; ...
, and
Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...
since ancient times, e.g. the production of Eri silk in
Assam, India Assam (; ) is a state in northeastern India, south of the eastern Himalayas along the Brahmaputra and Barak River valleys. Assam covers an area of . The state is bordered by Bhutan and Arunachal Pradesh to the north; Nagaland and Manipur to ...
. However, the scale of production was always far smaller than for cultivated silks. There are several reasons for this: first, they differ from the domesticated varieties in colour and
texture Texture may refer to: Science and technology * Surface texture, the texture means smoothness, roughness, or bumpiness of the surface of an object * Texture (roads), road surface characteristics with waves shorter than road roughness * Texture ...
and are therefore less uniform; second, cocoons gathered in the wild have usually had the pupa emerge from them before being discovered so the silk thread that makes up the cocoon has been torn into shorter lengths; and third, many wild cocoons are covered in a mineral layer that prevents attempts to reel from them long strands of silk. Thus, the only way to obtain silk suitable for spinning into textiles in areas where commercial silks are not cultivated was by tedious and labor-intensive
carding Carding is a mechanical process that disentangles, cleans and intermixes fibres to produce a continuous web or sliver (textiles), sliver suitable for subsequent processing. This is achieved by passing the fibres between differentially moving su ...
. Some natural silk structures have been used without being unwound or spun. Spider webs were used as a wound dressing in ancient Greece and Rome, and as a base for
painting Painting is the practice of applying paint, pigment, color or other medium to a solid surface (called the "matrix" or "support"). The medium is commonly applied to the base with a brush, but other implements, such as knives, sponges, and ...
from the 16th century. Caterpillar nests were pasted together to make a fabric in the
Aztec Empire The Aztec Empire or the Triple Alliance ( nci, Ēxcān Tlahtōlōyān, Help:IPA/Nahuatl, jéːʃkaːn̥ t͡ɬaʔtoːˈlóːjaːn̥ was an alliance of three Nahua peoples, Nahua altepetl, city-states: , , and . These three city-states ruled ...
. Commercial silks originate from reared silkworm pupae, which are bred to produce a white-colored silk thread with no mineral on the surface. The pupae are killed by either dipping them in boiling water before the adult moths emerge or by piercing them with a needle. These factors all contribute to the ability of the whole cocoon to be unravelled as one continuous thread, permitting a much stronger cloth to be woven from the silk. Wild silks also tend to be more difficult to dye than silk from the cultivated silkworm. A technique known as demineralizing allows the mineral layer around the cocoon of wild silk moths to be removed, leaving only variability in color as a barrier to creating a commercial silk industry based on wild silks in the parts of the world where wild silk moths thrive, such as in Africa and South America.


China

Silk use in fabric was first developed in ancient China. The earliest evidence for silk is the presence of the silk protein
fibroin Fibroin is an insoluble protein present in silk produced by numerous insects, such as the larvae of ''Bombyx mori'', and other moth genera such as '' Antheraea'', '' Cricula'', '' Samia'' and '' Gonometa''. Silk in its raw state consists of tw ...
in soil samples from two tombs at the
neolithic The Neolithic period, or New Stone Age, is an Old World archaeological period and the final division of the Stone Age. It saw the Neolithic Revolution, a wide-ranging set of developments that appear to have arisen independently in several parts ...
site Jiahu in
Henan Henan (; or ; ; alternatively Honan) is a landlocked province of China, in the central part of the country. Henan is often referred to as Zhongyuan or Zhongzhou (), which literally means "central plain" or "midland", although the name is al ...
, which date back about 8,500 years. The earliest surviving example of silk fabric dates from about 3630 BC, and was used as the wrapping for the body of a child at a
Yangshao culture The Yangshao culture (仰韶文化, pinyin: Yǎngsháo wénhuà) was a Neolithic culture that existed extensively along the middle reaches of the Yellow River in China from around 5000 BC to 3000 BC. The culture is named after the Yangsh ...
site in Qingtaicun near
Xingyang Xingyang (), is a county-level city of Henan Province, South Central China, it is under the administration of the prefecture-level city of Zhengzhou. It is situated 15 kilometers to the west of Zhengzhou city proper. The population of Xingyang is ...
, Henan. Legend gives credit for developing silk to a Chinese empress,
Leizu Leizu (), also known as Xi Ling-shi (, Wade–Giles Hsi Ling-shih), was a legendary Chinese empress and wife of the Yellow Emperor. According to tradition, she discovered sericulture, and invented the silk loom, in the 27th century BC. Myths A ...
(Hsi-Ling-Shih, Lei-Tzu). Silks were originally reserved for the Emperors of China for their own use and gifts to others, but spread gradually through
Chinese culture Chinese culture () is one of the world's oldest cultures, originating thousands of years ago. The culture prevails across a large geographical region in East Asia and is extremely diverse and varying, with customs and traditions varying grea ...
and trade both geographically and socially, and then to many regions of
Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...
. Because of its texture and lustre, silk rapidly became a popular luxury fabric in the many areas accessible to Chinese merchants. Silk was in great demand, and became a staple of pre-
industrial Industrial may refer to: Industry * Industrial archaeology, the study of the history of the industry * Industrial engineering, engineering dealing with the optimization of complex industrial processes or systems * Industrial city, a city dominate ...
international
trade Trade involves the transfer of goods and services from one person or entity to another, often in exchange for money. Economists refer to a system or network that allows trade as a market. An early form of trade, barter, saw the direct excha ...
. Silk was also used as a surface for writing, especially during the Warring States period (475-221 BCE). The fabric was light, it survived the damp climate of the Yangtze region, absorbed ink well, and provided a white background for the text. In July 2007, archaeologists discovered intricately woven and dyed silk
textile Textile is an umbrella term that includes various fiber-based materials, including fibers, yarns, filaments, threads, different fabric types, etc. At first, the word "textiles" only referred to woven fabrics. However, weaving is not the ...
s in a tomb in
Jiangxi Jiangxi (; ; formerly romanized as Kiangsi or Chianghsi) is a landlocked province in the east of the People's Republic of China. Its major cities include Nanchang and Jiujiang. Spanning from the banks of the Yangtze river in the north int ...
province, dated to the Eastern
Zhou dynasty The Zhou dynasty ( ; Old Chinese ( B&S): *''tiw'') was a royal dynasty of China that followed the Shang dynasty. Having lasted 789 years, the Zhou dynasty was the longest dynastic regime in Chinese history. The military control of China by th ...
roughly 2,500 years ago. Although historians have suspected a long history of a formative textile industry in ancient China, this find of silk textiles employing "complicated techniques" of weaving and dyeing provides direct evidence for silks dating before the
Mawangdui Mawangdui () is an archaeological site located in Changsha, China. The site consists of two saddle-shaped hills and contained the tombs of three people from the Changsha Kingdom during the western Han dynasty (206 BC – 9 AD): the Chancellor Li ...
-discovery and other silks dating to the
Han dynasty The Han dynasty (, ; ) was an imperial dynasty of China (202 BC – 9 AD, 25–220 AD), established by Liu Bang (Emperor Gao) and ruled by the House of Liu. The dynasty was preceded by the short-lived Qin dynasty (221–207 BC) and a warr ...
(202 BC – 220 AD). Silk is described in a chapter of the ''
Fan Shengzhi shu ''Fan Shengzhi shu'' ("Fan Shengzhi's book" or "Fan Shengzhi's manual") was a Chinese agricultural text from the Han dynasty, written by Fan Shengzhi in the first century BC. The book was lost in the 11th- or 12th-century Song dynasty, possibly dur ...
'' from the Western Han (202 BC – 9 AD). There is a surviving calendar for silk production in an Eastern Han (25–220 AD) document. The two other known works on silk from the Han period are lost. The first evidence of the long distance silk trade is the finding of silk in the hair of an
Egypt Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Mediter ...
ian
mummy A mummy is a dead human or an animal whose soft tissues and organs have been preserved by either intentional or accidental exposure to chemicals, extreme cold, very low humidity, or lack of air, so that the recovered body does not decay fu ...
of the 21st dynasty, c.1070 BC. The silk trade reached as far as the
Indian subcontinent The Indian subcontinent is a list of the physiographic regions of the world, physiographical region in United Nations geoscheme for Asia#Southern Asia, Southern Asia. It is situated on the Indian Plate, projecting southwards into the Indian O ...
, the
Middle East The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabian Peninsula, Arabia (including the Arabian Peninsula and Bahrain), Anatolia, Asia Minor (Asian part of Turkey except Hatay Pro ...
,
Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...
, and
North Africa North Africa, or Northern Africa is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region, and it is sometimes defined as stretching from the Atlantic shores of Mauritania in ...
. This trade was so extensive that the major set of trade routes between Europe and Asia came to be known as the
Silk Road The Silk Road () was a network of Eurasian trade routes active from the second century BCE until the mid-15th century. Spanning over 6,400 kilometers (4,000 miles), it played a central role in facilitating economic, cultural, political, and reli ...
. The
Emperors of China ''Huangdi'' (), translated into English as Emperor, was the superlative title held by monarchs of China who ruled various imperial regimes in Chinese history. In traditional Chinese political theory, the emperor was considered the Son of Heave ...
strove to keep knowledge of
sericulture Sericulture, or silk farming, is the cultivation of silkworms to produce silk. Although there are several commercial species of silkworms, ''Bombyx mori'' (the caterpillar of the domestic silkmoth) is the most widely used and intensively studie ...
secret to maintain the Chinese
monopoly A monopoly (from Greek language, Greek el, μόνος, mónos, single, alone, label=none and el, πωλεῖν, pōleîn, to sell, label=none), as described by Irving Fisher, is a market with the "absence of competition", creating a situati ...
. Nonetheless, sericulture reached
Korea Korea ( ko, 한국, or , ) is a peninsular region in East Asia. Since 1945, it has been divided at or near the 38th parallel, with North Korea (Democratic People's Republic of Korea) comprising its northern half and South Korea (Republic o ...
with technological aid from China around 200 BC, the ancient
Kingdom of Khotan The Kingdom of Khotan was an ancient Buddhist Saka kingdom located on the branch of the Silk Road that ran along the southern edge of the Taklamakan Desert in the Tarim Basin (modern Xinjiang, China). The ancient capital was originally sited to ...
by AD 50, and India by AD 140. In the ancient era, silk from China was the most lucrative and sought-after luxury item traded across the Eurasian continent, and many civilizations, such as the ancient Persians, benefited economically from trade. File:Women placing silkworms on trays together with mulberry leaves (Sericulture by Liang Kai, 1200s).jpg , The silkworms and mulberry leaves are placed on trays. File:Men preparing twig frames where silkworms will spin cocoons (Sericulture by Liang Kai, 1200s).jpg, Twig frames for the silkworms are prepared. File:Weighing and sorting the cocoons (Sericulture by Liang Kai, 1200s).jpg, The cocoons are weighed. File:Soaking the cocoons and reeling the silk (Sericulture by Liang Kai, 1200s).jpg, The cocoons are soaked and the silk is wound on spools. File:Weaving the silk (Sericulture by Liang Kai, 1200s).jpg, The silk is woven using a loom.


India

Silk has a long history in India. It is known as ''Resham'' in eastern and north India, and ''Pattu'' in southern parts of
India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
. Recent archaeological discoveries in
Harappa Harappa (; Urdu/ pnb, ) is an archaeological site in Punjab, Pakistan, about west of Sahiwal. The Bronze Age Harappan civilisation, now more often called the Indus Valley Civilisation, is named after the site, which takes its name from a mode ...
and Chanhu-daro suggest that
sericulture Sericulture, or silk farming, is the cultivation of silkworms to produce silk. Although there are several commercial species of silkworms, ''Bombyx mori'' (the caterpillar of the domestic silkmoth) is the most widely used and intensively studie ...
, employing
wild silk Wild silks have been known and used in many countries from early times, although the scale of production is far smaller than that from cultivated silkworms. Silk cocoons and nests often resemble paper or cloth, and their use has arisen independent ...
threads from native
silkworm The domestic silk moth (''Bombyx mori''), is an insect from the moth family Bombycidae. It is the closest relative of ''Bombyx mandarina'', the wild silk moth. The silkworm is the larva or caterpillar of a silk moth. It is an economically imp ...
species, existed in
South Asia South Asia is the southern subregion of Asia, which is defined in both geographical and ethno-cultural terms. The region consists of the countries of Afghanistan, Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan, and Sri Lanka.;;;;;;;; ...
during the time of the
Indus Valley civilisation The Indus Valley Civilisation (IVC), also known as the Indus Civilisation was a Bronze Age civilisation in the northwestern regions of South Asia, lasting from 3300 BCE to 1300 BCE, and in its mature form 2600 BCE to 1900&n ...
(now in
Pakistan Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a population of almost 24 ...
and India) dating between 2450 BC and 2000 BC. Shelagh Vainker, a silk expert at the
Ashmolean Museum The Ashmolean Museum of Art and Archaeology () on Beaumont Street, Oxford, England, is Britain's first public museum. Its first building was erected in 1678–1683 to house the cabinet of curiosities that Elias Ashmole gave to the University of ...
in Oxford, who sees evidence for silk production in China "significantly earlier" than 2500–2000 BC, suggests, "people of the Indus civilization either harvested silkworm cocoons or traded with people who did, and that they knew a considerable amount about silk." India is the second largest producer of silk in the world after China. About 97% of the raw mulberry silk comes from six Indian states, namely,
Andhra Pradesh Andhra Pradesh (, abbr. AP) is a state in the south-eastern coastal region of India. It is the seventh-largest state by area covering an area of and tenth-most populous state with 49,386,799 inhabitants. It is bordered by Telangana to the ...
,
Karnataka Karnataka (; ISO: , , also known as Karunāḍu) is a state in the southwestern region of India. It was formed on 1 November 1956, with the passage of the States Reorganisation Act. Originally known as Mysore State , it was renamed ''Karnat ...
, Jammu and Kashmir,
Tamil Nadu Tamil Nadu (; , TN) is a States and union territories of India, state in southern India. It is the List of states and union territories of India by area, tenth largest Indian state by area and the List of states and union territories of India ...
,
Bihar Bihar (; ) is a state in eastern India. It is the 2nd largest state by population in 2019, 12th largest by area of , and 14th largest by GDP in 2021. Bihar borders Uttar Pradesh to its west, Nepal to the north, the northern part of West Be ...
, and
West Bengal West Bengal (, Bengali: ''Poshchim Bongo'', , abbr. WB) is a state in the eastern portion of India. It is situated along the Bay of Bengal, along with a population of over 91 million inhabitants within an area of . West Bengal is the fourt ...
. North Bangalore, the upcoming site of a $20 million "Silk City"
Ramanagara Ramanagara is a city in the Indian state of Karnataka. It is also the headquarters of Ramanagara district. It is approximately 50 kilometres from Bangalore. There are buses and trains as public transportations which approximately takes 90 minute ...
and
Mysore Mysore (), officially Mysuru (), is a city in the southern part of the state of Karnataka, India. Mysore city is geographically located between 12° 18′ 26″ north latitude and 76° 38′ 59″ east longitude. It is located at an altitude of ...
, contribute to a majority of silk production in Karnataka. In
Tamil Nadu Tamil Nadu (; , TN) is a States and union territories of India, state in southern India. It is the List of states and union territories of India by area, tenth largest Indian state by area and the List of states and union territories of India ...
, mulberry cultivation is concentrated in the
Coimbatore Coimbatore, also spelt as Koyamputhur (), sometimes shortened as Kovai (), is one of the major metropolitan cities in the Indian state of Tamil Nadu. It is located on the banks of the Noyyal River and surrounded by the Western Ghats. Coimbato ...
,
Erode Erode () is a city in the Indian state of Tamil Nadu. Erode is the seventh largest urban agglomeration in the state, after Chennai, Coimbatore, Madurai, Tiruchirapalli, Tiruppur and Salem. It is also the administrative headquarters of the E ...
,
Bhagalpur Bhagalpur is a city in the Indian state of Bihar, situated on the southern banks of the river Ganges. It is the 2nd largest city of Bihar by population and also the headquarters of Bhagalpur district and Bhagalpur division. Known as the Silk ...
i,
Tiruppur Tiruppur or Tirupur ( ) is a city in the Indian state of Tamil Nadu. Tiruppur is the administrative headquarters of Tiruppur district and the fifth largest city as well as an urban agglomeration in Tamil Nadu. Located on the banks of Noyyal Ri ...
, Salem, and
Dharmapuri Dharmapuri is a special grade town in the north western part of Tamil Nadu, India. It serves as the administrative headquarters of Dharmapuri district which is the first district created in Tamil Nadu after the independence of India by splitti ...
districts.
Hyderabad Hyderabad ( ; , ) is the capital and largest city of the Indian state of Telangana and the ''de jure'' capital of Andhra Pradesh. It occupies on the Deccan Plateau along the banks of the Musi River (India), Musi River, in the northern part ...
,
Andhra Pradesh Andhra Pradesh (, abbr. AP) is a state in the south-eastern coastal region of India. It is the seventh-largest state by area covering an area of and tenth-most populous state with 49,386,799 inhabitants. It is bordered by Telangana to the ...
, and
Gobichettipalayam Gobichettipalayam () is the Selection grade municipality in the Indian state of Tamil Nadu. It is the administrative headquarters of Gobichettipalayam taluk. It is situated at the center of the South Indian Peninsula, from the district hea ...
,
Tamil Nadu Tamil Nadu (; , TN) is a States and union territories of India, state in southern India. It is the List of states and union territories of India by area, tenth largest Indian state by area and the List of states and union territories of India ...
, were the first locations to have automated silk reeling units in India. In the northeastern state of
Assam Assam (; ) is a state in northeastern India, south of the eastern Himalayas along the Brahmaputra and Barak River valleys. Assam covers an area of . The state is bordered by Bhutan and Arunachal Pradesh to the north; Nagaland and Manipur ...
, three different types of indigenous variety of silk are produced, collectively called Assam silk:
Muga silk Muga silk is a variety of wild silk geographically tagged to the state of Assam in India. The silk is known for its extreme durability and has a natural yellowish-golden tint with a shimmering, glossy texture. It was previously reserved for the u ...
,
Eri silk Eri silk (Khasi'': Ryndia)'' is the product of the domesticated silkworm '' Samia ricini'', found mainly in North East India and some part of China and Japan. It was imported to Thailand in 1974. The name "eri" is derived from the Assamese word ...
and Pat silk. Muga, the golden silk, and Eri are produced by silkworms that are native only to Assam. They have been reared since ancient times similar to other East and South-East Asian countries.


Thailand

Silk is produced year-round in Thailand by two types of silkworms, the cultured Bombycidae and wild Saturniidae. Most production is after the rice harvest in the southern and northeastern parts of the country. Women traditionally weave silk on hand looms and pass the skill on to their daughters, as weaving is considered to be a sign of maturity and eligibility for marriage. Thai silk textiles often use complicated patterns in various colours and styles. Most regions of Thailand have their own typical silks. A single thread filament is too thin to use on its own so women combine many threads to produce a thicker, usable fiber. They do this by hand-reeling the threads onto a wooden spindle to produce a uniform strand of raw silk. The process takes around 40 hours to produce a half kilogram of silk. Many local operations use a reeling machine for this task, but some silk threads are still hand-reeled. The difference is that hand-reeled threads produce three grades of silk: two fine grades that are ideal for lightweight fabrics, and a thick grade for heavier material. The silk fabric is soaked in extremely cold water and bleached before dyeing to remove the natural yellow coloring of Thai silk yarn. To do this, skeins of silk thread are immersed in large tubs of
hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3% ...
. Once washed and dried, the silk is woven on a traditional hand-operated loom.


Bangladesh

The
Rajshahi Division Rajshahi Division ( bn, রাজশাহী বিভাগ) is one of the eight first-level administrative divisions of Bangladesh. It has an area of and a population at the 2011 Census of 18,484,858. Rajshahi Division consists of 8 district ...
of northern Bangladesh is the hub of the country's silk industry. There are three types of silk produced in the region: mulberry, endi, and tassar.
Bengal Bengal ( ; bn, বাংলা/বঙ্গ, translit=Bānglā/Bôngô, ) is a geopolitical, cultural and historical region in South Asia, specifically in the eastern part of the Indian subcontinent at the apex of the Bay of Bengal, predom ...
i silk was a major item of international trade for centuries. It was known as Ganges silk in medieval Europe. Bengal was the leading exporter of silk between the 16th and 19th centuries.


Central Asia

The 7th century CE murals of Afrasiyab in
Samarkand fa, سمرقند , native_name_lang = , settlement_type = City , image_skyline = , image_caption = Clockwise from the top:Registan square, Shah-i-Zinda necropolis, Bibi-Khanym Mosque, view inside Shah-i-Zinda, ...
,
Sogdiana Sogdia ( Sogdian: ) or Sogdiana was an ancient Iranian civilization between the Amu Darya and the Syr Darya, and in present-day Uzbekistan, Turkmenistan, Tajikistan, Kazakhstan, and Kyrgyzstan. Sogdiana was also a province of the Achaemenid Emp ...
, show a Chinese Embassy carrying silk and a string of silkworm cocoons to the local Sogdian ruler.


Middle East

In the
Torah The Torah (; hbo, ''Tōrā'', "Instruction", "Teaching" or "Law") is the compilation of the first five books of the Hebrew Bible, namely the books of Genesis, Exodus, Leviticus, Numbers and Deuteronomy. In that sense, Torah means the s ...
, a scarlet cloth item called in Hebrew "sheni tola'at" שני תולעת – literally "crimson of the worm" – is described as being used in purification ceremonies, such as those following a leprosy outbreak (Leviticus 14), alongside
cedar wood Cedar is part of the English common name of many trees and other plants, particularly those of the genus ''Cedrus''. Some botanical authorities consider the Old-World ''Cedrus'' the only "true cedars". Many other species worldwide with similarl ...
and
hyssop ''Hyssopus officinalis'' or hyssop is a shrub in the Lamiaceae or mint family native to Southern Europe, the Middle East, and the region surrounding the Caspian Sea. Due to its purported properties as an antiseptic, cough reliever, and expecto ...
(
za'atar Za'atar ( ; ar, زَعْتَر, ) is a culinary herb or family of herbs. It is also the name of a spice mixture that includes the herb along with toasted sesame seeds, dried sumac, often salt, as well as other spices. As a family of related ...
). Eminent scholar and leading medieval translator of
Jewish Jews ( he, יְהוּדִים, , ) or Jewish people are an ethnoreligious group and nation originating from the Israelites Israelite origins and kingdom: "The first act in the long drama of Jewish history is the age of the Israelites""The ...
sources and books of the
Bible The Bible (from Koine Greek , , 'the books') is a collection of religious texts or scriptures that are held to be sacred in Christianity, Judaism, Samaritanism, and many other religions. The Bible is an anthologya compilation of texts of a ...
into
Arabic Arabic (, ' ; , ' or ) is a Semitic languages, Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C ...
, Rabbi
Saadia Gaon Saʻadiah ben Yosef Gaon ( ar, سعيد بن يوسف الفيومي ''Saʻīd bin Yūsuf al-Fayyūmi''; he, סַעֲדְיָה בֶּן יוֹסֵף אַלְפַיּוּמִי גָּאוֹן ''Saʿăḏyāh ben Yōsēf al-Fayyūmī Gāʾōn''; ...
, translates this phrase explicitly as "crimson silk" – חריר קרמז حرير قرمز. In
Islamic Islam (; ar, ۘالِإسلَام, , ) is an Abrahamic monotheistic religion centred primarily around the Quran, a religious text considered by Muslims to be the direct word of God (or '' Allah'') as it was revealed to Muhammad, the mai ...
teachings, Muslim men are forbidden to wear silk. Many religious jurists believe the reasoning behind the prohibition lies in avoiding clothing for men that can be considered feminine or extravagant. There are disputes regarding the amount of silk a fabric can consist of (e.g., whether a small decorative silk piece on a cotton caftan is permissible or not) for it to be lawful for men to wear, but the dominant opinion of most Muslim scholars is that the wearing of silk by men is forbidden. Modern attire has raised a number of issues, including, for instance, the permissibility of wearing silk
necktie A necktie, or simply a tie, is a piece of cloth worn for decorative purposes around the neck, resting under the shirt collar and knotted at the throat, and often draped down the chest. Variants include the ascot, bow, bolo, zipper tie, cra ...
s, which are masculine articles of clothing.


Ancient Mediterranean

In the ''
Odyssey The ''Odyssey'' (; grc, Ὀδύσσεια, Odýsseia, ) is one of two major Ancient Greek literature, ancient Greek Epic poetry, epic poems attributed to Homer. It is one of the oldest extant works of literature still widely read by moder ...
'', 19.233, when Odysseus, while pretending to be someone else, is questioned by Penelope about her husband's clothing, he says that he wore a shirt "gleaming like the skin of a dried onion" (varies with translations, literal translation here) which could refer to the lustrous quality of silk fabric.
Aristotle Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatetic school of phil ...
wrote of ''
Coa vestis Coa vestis is an ancient type of fabric named after its point of origin, the Greek island Kos. ''Coa vestis'' was made by the wild silk of '' Pachypasa otus'', a Mediterranean moth.
'', a wild silk textile from
Kos Kos or Cos (; el, Κως ) is a Greek island, part of the Dodecanese island chain in the southeastern Aegean Sea. Kos is the third largest island of the Dodecanese by area, after Rhodes and Karpathos; it has a population of 36,986 (2021 census), ...
.
Sea silk Sea silk is an extremely fine, rare, and valuable fabric that is made from the long silky filaments or byssus secreted by a gland in the foot of pen shells (in particular ''Pinna nobilis''). The byssus is used by the clam to attach itself to t ...
from certain large sea shells was also valued. The
Roman Empire The Roman Empire ( la, Imperium Romanum ; grc-gre, Βασιλεία τῶν Ῥωμαίων, Basileía tôn Rhōmaíōn) was the post-Republican period of ancient Rome. As a polity, it included large territorial holdings around the Mediterr ...
knew of and traded in silk, and Chinese silk was the most highly priced luxury good imported by them. During the reign of emperor
Tiberius Tiberius Julius Caesar Augustus (; 16 November 42 BC – 16 March AD 37) was the second Roman emperor. He reigned from AD 14 until 37, succeeding his stepfather, the first Roman emperor Augustus. Tiberius was born in Rome in 42 BC. His father ...
,
sumptuary law Sumptuary laws (from Latin ''sūmptuāriae lēgēs'') are laws that try to regulate consumption. '' Black's Law Dictionary'' defines them as "Laws made for the purpose of restraining luxury or extravagance, particularly against inordinate expendi ...
s were passed that forbade men from wearing silk garments, but these proved ineffectual. The
Historia Augusta The ''Historia Augusta'' (English: ''Augustan History'') is a late Roman collection of biographies, written in Latin, of the Roman emperors, their junior colleagues, designated heirs and usurpers from 117 to 284. Supposedly modeled on the sim ...
mentions that the third-century emperor
Elagabalus Marcus Aurelius Antoninus (born Sextus Varius Avitus Bassianus, 204 – 11/12 March 222), better known by his nickname "Elagabalus" (, ), was Roman emperor from 218 to 222, while he was still a teenager. His short reign was conspicuous for s ...
was the first Roman to wear garments of pure silk, whereas it had been customary to wear fabrics of silk/cotton or silk/linen blends. Despite the popularity of silk, the secret of silk-making only reached Europe around AD 550, via the
Byzantine Empire The Byzantine Empire, also referred to as the Eastern Roman Empire or Byzantium, was the continuation of the Roman Empire primarily in its eastern provinces during Late Antiquity and the Middle Ages, when its capital city was Constantinopl ...
. Contemporary accounts state that monks working for the emperor
Justinian I Justinian I (; la, Iustinianus, ; grc-gre, Ἰουστινιανός ; 48214 November 565), also known as Justinian the Great, was the Byzantine emperor from 527 to 565. His reign is marked by the ambitious but only partly realized ''renovat ...
smuggled silkworm eggs to
Constantinople la, Constantinopolis ota, قسطنطينيه , alternate_name = Byzantion (earlier Greek name), Nova Roma ("New Rome"), Miklagard/Miklagarth (Old Norse), Tsargrad ( Slavic), Qustantiniya (Arabic), Basileuousa ("Queen of Cities"), Megalopolis (" ...
from China inside hollow canes. All top-quality looms and weavers were located inside the Great Palace complex in Constantinople, and the cloth produced was used in imperial robes or in diplomacy, as gifts to foreign dignitaries. The remainder was sold at very high prices.


Medieval and modern Europe

Italy was the most important producer of silk during the Medieval age. The first center to introduce silk production to Italy was the city of
Catanzaro Catanzaro (, or ; scn, label= Catanzarese, Catanzaru ; , or , ''Katastaríoi Lokrói''; ; la, Catacium), also known as the "City of the two Seas", is an Italian city of 86,183 inhabitants (2020), the capital of the Calabria region and of its p ...
during the 11th century in the region of
Calabria , population_note = , population_blank1_title = , population_blank1 = , demographics_type1 = , demographics1_footnotes = , demographics1_title1 = , demographics1_info1 = , demographics1_title2 ...
. The silk of Catanzaro supplied almost all of Europe and was sold in a large market fair in the port of
Reggio Calabria Reggio di Calabria ( scn, label= Southern Calabrian, Riggiu; el, label= Calabrian Greek, Ρήγι, Rìji), usually referred to as Reggio Calabria, or simply Reggio by its inhabitants, is the largest city in Calabria. It has an estimated popul ...
, to Spanish, Venetian, Genovese, and Dutch merchants. Catanzaro became the lace capital of the world with a large silkworm breeding facility that produced all the laces and linens used in the Vatican. The city was world-famous for its fine fabrication of silks, velvets, damasks, and brocades. Another notable center was the Italian
city-state A city-state is an independent sovereign city which serves as the center of political, economic, and cultural life over its contiguous territory. They have existed in many parts of the world since the dawn of history, including cities such as ...
of
Lucca Lucca ( , ) is a city and ''comune'' in Tuscany, Central Italy, on the Serchio River, in a fertile plain near the Ligurian Sea. The city has a population of about 89,000, while its province has a population of 383,957. Lucca is known as one o ...
which largely financed itself through silk-production and silk-trading, beginning in the 12th century. Other Italian cities involved in silk production were
Genoa Genoa ( ; it, Genova ; lij, Zêna ). is the capital of the Italian region of Liguria and the List of cities in Italy, sixth-largest city in Italy. In 2015, 594,733 people lived within the city's administrative limits. As of the 2011 Italian ce ...
,
Venice Venice ( ; it, Venezia ; vec, Venesia or ) is a city in northeastern Italy and the capital of the Veneto Regions of Italy, region. It is built on a group of 118 small islands that are separated by canals and linked by over 400  ...
, and
Florence Florence ( ; it, Firenze ) is a city in Central Italy and the capital city of the Tuscany region. It is the most populated city in Tuscany, with 383,083 inhabitants in 2016, and over 1,520,000 in its metropolitan area.Bilancio demografico an ...
. The
Piedmont it, Piemontese , population_note = , population_blank1_title = , population_blank1 = , demographics_type1 = , demographics1_footnotes = , demographics1_title1 = , demographics1_info1 = , demographics1_title2 ...
area of Northern Italy became a major silk producing area when water-powered silk throwing machines were developed. The Silk Exchange in Valencia from the 15th century—where previously in 1348 also ''perxal'' (
percale Percale is a closely woven plain-weave fabric often used for bed covers. Percale has a thread count of about 200 or higher and is noticeably tighter than the standard type of weave used for bedsheets. It has medium weight, is firm and smooth w ...
) was traded as some kind of silk—illustrates the power and wealth of one of the great Mediterranean mercantile cities. Silk was produced in and exported from the province of
Granada Granada (,, DIN 31635, DIN: ; grc, Ἐλιβύργη, Elibýrgē; la, Illiberis or . ) is the capital city of the province of Granada, in the autonomous communities of Spain, autonomous community of Andalusia, Spain. Granada is located at the fo ...
, Spain, especially the
Alpujarras The Alpujarra (, Arabic: ''al-bussarat'') is a natural and historical region in Andalusia, Spain, on the south slopes of the Sierra Nevada and the adjacent valley. The average elevation is above sea level. It extends over two provinces, ...
region, until the
Moriscos Moriscos (, ; pt, mouriscos ; Spanish for "Moorish") were former Muslims and their descendants whom the Roman Catholic church and the Spanish Crown commanded to convert to Christianity or face compulsory exile after Spain outlawed the open ...
, whose industry it was, were expelled from Granada in 1571. Since the 15th century, silk production in France has been centered around the city of
Lyon Lyon,, ; Occitan: ''Lion'', hist. ''Lionés'' also spelled in English as Lyons, is the third-largest city and second-largest metropolitan area of France. It is located at the confluence of the rivers Rhône and Saône, to the northwest of t ...
where many mechanic tools for mass production were first introduced in the 17th century.
James I James I may refer to: People *James I of Aragon (1208–1276) *James I of Sicily or James II of Aragon (1267–1327) *James I, Count of La Marche (1319–1362), Count of Ponthieu *James I, Count of Urgell (1321–1347) *James I of Cyprus (1334–13 ...
attempted to establish silk production in England, purchasing and planting 100,000 mulberry trees, some on land adjacent to
Hampton Court Palace Hampton Court Palace is a Grade I listed royal palace in the London Borough of Richmond upon Thames, southwest and upstream of central London on the River Thames. The building of the palace began in 1514 for Cardinal Thomas Wolsey, the chie ...
, but they were of a species unsuited to the silk worms, and the attempt failed. In 1732 John Guardivaglio set up a
silk throwing Silk throwing is the industrial process wherein silk that has been reeled into skeins, is cleaned, receives a twist and is wound onto bobbins. The yarn is now twisted together with threads, in a process known as ''doubling''. Colloquially silk thr ...
enterprise at Logwood mill in Stockport; in 1744, Burton Mill was erected in
Macclesfield Macclesfield is a market town and civil parish in the unitary authority of Cheshire East in Cheshire, England. It is located on the River Bollin in the east of the county, on the edge of the Cheshire Plain, with Macclesfield Forest to its east ...
; and in 1753 Old Mill was built in
Congleton Congleton is a town and civil parish in the unitary authority of Cheshire East in Cheshire, England. The town is by the River Dane, south of Manchester and north of Stoke on Trent. At the 2011 Census, it had a population of 26,482. Top ...
. These three towns remained the centre of the English silk throwing industry until silk throwing was replaced by silk waste spinning. British enterprise also established silk filature in
Cyprus Cyprus ; tr, Kıbrıs (), officially the Republic of Cyprus,, , lit: Republic of Cyprus is an island country located south of the Anatolian Peninsula in the eastern Mediterranean Sea. Its continental position is disputed; while it is geo ...
in 1928. In England in the mid-20th century, raw silk was produced at
Lullingstone Castle Lullingstone Castle is a historic manor house, set in an estate in the village of Lullingstone and the civil parish of Eynsford in the English county of Kent. It has been inhabited by members of the Hart Dyke family for twenty generations incl ...
in Kent. Silkworms were raised and reeled under the direction of Zoe Lady Hart Dyke, later moving to
Ayot St Lawrence Ayot St Lawrence is a small English village and civil parish in Hertfordshire, west of Welwyn. There are several other ''Ayots'' in the area, including Ayot Green and Ayot St Peter, where the census population of Ayot St Lawrence was included ...
in Hertfordshire in 1956. During
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
, supplies of silk for UK parachute manufacture were secured from the Middle East by Peter Gaddum. File:Vestido Javiera Carrera.jpg, Dress made from silk File:WLA vanda Bed lit a la polonaise.jpg, Bed covered with silk File:"Almgrensrosen"- ett 100 år gammalt mönster 2013.JPG, A hundred-year-old pattern of silk called "Almgrensrosen" File:Necktie knot.jpg, The
necktie A necktie, or simply a tie, is a piece of cloth worn for decorative purposes around the neck, resting under the shirt collar and knotted at the throat, and often draped down the chest. Variants include the ascot, bow, bolo, zipper tie, cra ...
originates from the
cravat Cravat, cravate or cravats may refer to: * Cravat (early), forerunner neckband of the modern necktie * Cravat, British name for what in American English is called an ascot tie * Cravat bandage, a triangular bandage * Cravat (horse) (1935–1954), a ...
, a neckband made from silk


North America

Wild silk taken from the nests of native caterpillars was used by the
Aztecs The Aztecs () were a Mesoamerican culture that flourished in central Mexico in the post-classic period from 1300 to 1521. The Aztec people included different Indigenous peoples of Mexico, ethnic groups of central Mexico, particularly those g ...
to make containers and as paper. Silkworms were introduced to
Oaxaca Oaxaca ( , also , , from nci, Huāxyacac ), officially the Free and Sovereign State of Oaxaca ( es, Estado Libre y Soberano de Oaxaca), is one of the 32 states that compose the political divisions of Mexico, Federative Entities of Mexico. It is ...
from Spain in the 1530s and the region profited from silk production until the early 17th century, when the king of Spain banned export to protect Spain's silk industry. Silk production for local consumption has continued until the present day, sometimes spinning wild silk. King
James I James I may refer to: People *James I of Aragon (1208–1276) *James I of Sicily or James II of Aragon (1267–1327) *James I, Count of La Marche (1319–1362), Count of Ponthieu *James I, Count of Urgell (1321–1347) *James I of Cyprus (1334–13 ...
introduced silk-growing to the British colonies in America around 1619, ostensibly to discourage
tobacco Tobacco is the common name of several plants in the genus '' Nicotiana'' of the family Solanaceae, and the general term for any product prepared from the cured leaves of these plants. More than 70 species of tobacco are known, but the ...
planting. The
Shakers The United Society of Believers in Christ's Second Appearing, more commonly known as the Shakers, are a Millenarianism, millenarian Restorationism, restorationist Christianity, Christian sect founded in England and then organized in the Unit ...
in Kentucky adopted the practice. The history of industrial silk in the United States is largely tied to several smaller urban centers in the Northeast region. Beginning in the 1830s,
Manchester, Connecticut Manchester is a town in Hartford County, Connecticut, United States. As of the 2020 census, the town had a total population of 59,713. The urban center of the town is the Manchester census-designated place, with a population of 36,379 at the 202 ...
emerged as the early center of the silk industry in America, when the Cheney Brothers became the first in the United States to properly raise silkworms on an industrial scale; today the
Cheney Brothers Historic District The Cheney Brothers Historic District was a center of the silk industry in Manchester, Connecticut, in the late 19th and early 20th century. The district includes over 275 mill buildings, workers houses, churches, schools and Cheney family mans ...
showcases their former mills. With the
mulberry tree ''Morus'', a genus of flowering plants in the family Moraceae, consists of diverse species of deciduous trees commonly known as mulberries, growing wild and under cultivation in many temperate world regions. Generally, the genus has 64 identif ...
craze of that decade, other smaller producers began raising silkworms. This economy particularly gained traction in the vicinity of
Northampton, Massachusetts The city of Northampton is the county seat of Hampshire County, Massachusetts, United States. As of the 2020 census, the population of Northampton (including its outer villages, Florence and Leeds) was 29,571. Northampton is known as an acade ...
and its neighboring Williamsburg, where a number of small firms and cooperatives emerged. Among the most prominent of these was the cooperative utopian Northampton Association for Education and Industry, of which
Sojourner Truth Sojourner Truth (; born Isabella Baumfree; November 26, 1883) was an American abolitionist of New York Dutch heritage and a women's rights activist. Truth was born into slavery in Swartekill, New York, but escaped with her infant daughter to f ...
was a member. Following the destructive
Mill River Flood of 1874 The Mill River is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed April 1, 2011 tributary of the Connecticut River arising in the western hilltowns of Hampshire County, Massachusett ...
, one manufacturer, William Skinner, relocated his mill from Williamsburg to the then-new city of
Holyoke Holyoke is a city in Hampden County, Massachusetts, United States, that lies between the western bank of the Connecticut River and the Mount Tom Range. As of the 2020 census, the city had a population of 38,238. Located north of Springfield ...
. Over the next 50 years he and his sons would maintain relations between the American silk industry and its counterparts in Japan, and expanded their business to the point that by 1911, the Skinner Mill complex contained the largest silk mill under one roof in the world, and the brand Skinner Fabrics had become the largest manufacturer of silk satins internationally. Other efforts later in the 19th century would also bring the new silk industry to
Paterson, New Jersey Paterson ( ) is the largest City (New Jersey), city in and the county seat of Passaic County, New Jersey, Passaic County, in the U.S. state of New Jersey.World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
interrupted the silk trade from Asia, and silk prices increased dramatically. U.S. industry began to look for substitutes, which led to the use of synthetics such as
nylon Nylon is a generic designation for a family of synthetic polymers composed of polyamides ( repeating units linked by amide links).The polyamides may be aliphatic or semi-aromatic. Nylon is a silk-like thermoplastic, generally made from petro ...
. Synthetic silks have also been made from
lyocell Lyocell, originally trademarked in 1982 as Tencel, is a form of regenerated cellulose. It consists of cellulose fibers, made by dissolving pulp and then reconstituting it by dry jet-wet spinning. The fiber is used to make textiles for clothing a ...
, a type of
cellulose Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wall ...
fiber, and are often difficult to distinguish from real silk (see
spider silk Spider silk is a protein fibre spun by spiders. Spiders use their silk to make Spider web, webs or other structures, which function as sticky nets to catch other animals, or as nests or cocoons to protect their offspring, or to wrap up prey. ...
for more on synthetic silks).


Malaysia

In
Terengganu Terengganu (; Terengganu Malay: ''Tranung'', Jawi: ), formerly spelled Trengganu or Tringganu, is a sultanate and constitutive state of federal Malaysia. The state is also known by its Arabic honorific, ''Dāru l- Īmān'' ("Abode of Faith"). ...
, which is now part of
Malaysia Malaysia ( ; ) is a country in Southeast Asia. The federation, federal constitutional monarchy consists of States and federal territories of Malaysia, thirteen states and three federal territories, separated by the South China Sea into two r ...
, a second generation of silkworm was being imported as early as 1764 for the country's silk textile industry, especially
songket ''Songket'' is a ''Tenun'' fabric that belongs to the brocade family of textiles of Brunei, Indonesia, Malaysia and Singapore. It is hand-woven in silk or cotton, and intricately patterned with gold or silver threads. It is hand-woven in ...
. However, since the 1980s, Malaysia is no longer engaged in sericulture but does plant mulberry trees.


Vietnam

In Vietnamese legend, silk appeared in the first millennium AD and is still being woven today.


Production process

The process of silk production is known as
sericulture Sericulture, or silk farming, is the cultivation of silkworms to produce silk. Although there are several commercial species of silkworms, ''Bombyx mori'' (the caterpillar of the domestic silkmoth) is the most widely used and intensively studie ...
. The entire production process of silk can be divided into several steps which are typically handled by different entities. Extracting raw silk starts by cultivating the silkworms on mulberry leaves. Once the worms start pupating in their cocoons, these are dissolved in boiling water in order for individual long fibres to be extracted and fed into the spinning reel. To produce 1 kg of silk, 104 kg of mulberry leaves must be eaten by 3000 silkworms. It takes about 5000 silkworms to make a pure silk
kimono The is a traditional Japanese garment and the national dress of Japan. The kimono is a wrapped-front garment with square sleeves and a rectangular body, and is worn left side wrapped over right, unless the wearer is deceased. The kimono ...
. The major silk producers are
China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
(54%) and
India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
(14%). Other statistics: The environmental impact of silk production is potentially large when compared with other natural fibers. A
life-cycle assessment Life cycle assessment or LCA (also known as life cycle analysis) is a methodology for assessing environmental impacts associated with all the stages of the Product lifecycle, life cycle of a commercial product, Process lifecycle, process, or ...
of Indian silk production shows that the production process has a large carbon and water footprint, mainly due to the fact that it is an animal-derived fiber and more inputs such as fertilizer and water are needed per unit of fiber produced.


Properties


Physical properties

Silk fibers from the ''Bombyx mori'' silkworm have a
triangular A triangle is a polygon with three edges and three vertices. It is one of the basic shapes in geometry. A triangle with vertices ''A'', ''B'', and ''C'' is denoted \triangle ABC. In Euclidean geometry, any three points, when non- collinea ...
cross section Cross section may refer to: * Cross section (geometry) ** Cross-sectional views in architecture & engineering 3D *Cross section (geology) * Cross section (electronics) * Radar cross section, measure of detectability * Cross section (physics) **Abs ...
with rounded corners, 5–10 μm wide. The fibroin-heavy chain is composed mostly of
beta-sheet The beta sheet, (β-sheet) (also β-pleated sheet) is a common motif of the regular protein secondary structure. Beta sheets consist of beta strands (β-strands) connected laterally by at least two or three backbone hydrogen bonds, forming a g ...
s, due to a 59-mer amino acid repeat sequence with some variations. The flat surfaces of the fibrils reflect
light Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 tera ...
at many angles, giving silk a natural sheen. The cross-section from other silkworms can vary in shape and diameter: crescent-like for ''Anaphe'' and elongated wedge for ''tussah''. Silkworm fibers are naturally extruded from two silkworm glands as a pair of primary filaments (brin), which are stuck together, with sericin proteins that act like
glue Adhesive, also known as glue, cement, mucilage, or paste, is any non-metallic substance applied to one or both surfaces of two separate items that binds them together and resists their separation. The use of adhesives offers certain advant ...
, to form a bave. Bave diameters for tussah silk can reach 65 μm. See cited reference for cross-sectional SEM photographs. Silk has a smooth, soft texture that is not slippery, unlike many
synthetic fiber Synthetic fibers or synthetic fibres (in British English; see spelling differences) are fibers made by humans through chemical synthesis, as opposed to natural fibers that are directly derived from living organisms, such as plants (like cotton) ...
s. Silk is one of the strongest natural fibers, but it loses up to 20% of its strength when wet. It has a good moisture regain of 11%. Its elasticity is moderate to poor: if elongated even a small amount, it remains stretched. It can be weakened if exposed to too much sunlight. It may also be attacked by insects, especially if left dirty. One example of the durable nature of silk over other fabrics is demonstrated by the recovery in 1840 of silk garments from a wreck of 1782: 'The most durable article found has been silk; for besides pieces of cloaks and lace, a pair of black satin breeches, and a large satin waistcoat with flaps, were got up, of which the silk was perfect, but the lining entirely gone ... from the thread giving way ... No articles of dress of woollen cloth have yet been found.' Silk is a poor conductor of
electricity Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described ...
and thus susceptible to
static cling Static cling is the tendency for light objects to stick (cling) to other objects owing to static electricity. It is common in clothing, but occurs with other items, such as the tendency of dust to be attracted to, and stick to, plastic items. ...
. Silk has a high emissivity for infrared light, making it feel cool to the touch. Unwashed silk chiffon may shrink up to 8% due to a relaxation of the fiber macrostructure, so silk should either be washed prior to garment construction, or dry cleaned. Dry cleaning may still shrink the chiffon up to 4%. Occasionally, this shrinkage can be reversed by a gentle steaming with a press cloth. There is almost no gradual shrinkage nor shrinkage due to molecular-level deformation. Natural and synthetic silk is known to manifest
piezoelectric Piezoelectricity (, ) is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied Stress (mechanics), mechanical s ...
properties in proteins, probably due to its molecular structure. Silkworm silk was used as the standard for the denier, a measurement of
linear density Linear density is the measure of a quantity of any characteristic value per unit of length. Linear mass density (titer in textile engineering, the amount of mass per unit length) and linear charge density (the amount of electric charge per unit ...
in fibers. Silkworm silk therefore has a linear density of approximately 1 den, or 1.1 dtex.


Chemical properties

Silk emitted by the silkworm consists of two main proteins,
sericin Sericin is a protein created by ''Bombyx mori'' (silkworms) in the production of silk. Silk is a fibre produced by the silkworm in production of its cocoon. It consists mainly of two proteins, fibroin and sericin. Silk consists of 70–80% f ...
and
fibroin Fibroin is an insoluble protein present in silk produced by numerous insects, such as the larvae of ''Bombyx mori'', and other moth genera such as '' Antheraea'', '' Cricula'', '' Samia'' and '' Gonometa''. Silk in its raw state consists of tw ...
, fibroin being the structural center of the silk, and sericin being the sticky material surrounding it. Fibroin is made up of the
amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...
s
Gly 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 (carbamic acid is unstable), with the chemical formula NH2‐ CH2‐ COOH. Glycine is one of the proteinogeni ...
-
Ser Ser or SER may refer to: Places * Ser, a village in Bogdand Commune, Satu Mare County, Romania * Serpens (Ser), an astronomical constellation of the northern hemisphere * Serres, known as Ser in Serbian, a city in Macedonia, Greece Organization ...
-Gly-
Ala Ala, ALA, Alaa or Alae may refer to: Places * Ala, Hiiu County, Estonia, a village * Ala, Valga County, Estonia, a village * Ala, Alappuzha, Kerala, India, a village * Ala, Iran, a village in Semnan Province * Ala, Gotland, Sweden * Alad, S ...
-Gly-Ala and forms beta pleated sheets.
Hydrogen bond In chemistry, a hydrogen bond (or H-bond) is a primarily electrostatic force of attraction between a hydrogen (H) atom which is covalently bound to a more electronegative "donor" atom or group (Dn), and another electronegative atom bearing a ...
s form between chains, and side chains form above and below the plane of the hydrogen bond network. The high proportion (50%) of glycine allows tight packing. This is because glycine's R group is only a hydrogen and so is not as sterically constrained. The addition of alanine and serine makes the fibres strong and resistant to breaking. This tensile strength is due to the many interceded hydrogen bonds, and when stretched the force is applied to these numerous bonds and they do not break. Silk resists most
mineral acid A mineral acid (or inorganic acid) is an acid derived from one or more inorganic compounds, as opposed to organic acids which are acidic, organic compounds. All mineral acids form hydrogen ions and the conjugate base when dissolved in water. Cha ...
s, except for
sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formu ...
, which dissolves it. It is yellowed by perspiration.
Chlorine bleach Bleach is the generic name for any chemical product that is used industrially or domestically to remove color (whitening) from a fabric or fiber or to clean or to remove stains in a process called bleaching. It often refers specifically, to ...
will also destroy silk fabrics.


Variants


Regenerated silk fiber

RSF is produced by chemically dissolving silkworm cocoons, leaving their molecular structure intact. The silk fibers dissolve into tiny thread-like structures known as
microfibril A microfibril is a very fine fibril, or fiber-like strand, consisting of glycoproteins and cellulose. It is usually, but not always, used as a general term in describing the structure of protein fiber, e.g. hair and sperm tail. Its most frequently ...
s. The resulting solution is extruded through a small opening, causing the microfibrils to reassemble into a single fiber. The resulting material is reportedly twice as stiff as silk.


Applications


Clothing

Silk's absorbency makes it comfortable to wear in warm weather and while active. Its low conductivity keeps warm air close to the skin during cold weather. It is often used for clothing such as
shirt A shirt is a cloth garment for the upper body (from the neck to the waist). Originally an undergarment worn exclusively by men, it has become, in American English, a catch-all term for a broad variety of upper-body garments and undergarments. I ...
s,
ties TIES may refer to: * TIES, Teacher Institute for Evolutionary Science * TIES, The Interactive Encyclopedia System * TIES, Time Independent Escape Sequence * Theoretical Issues in Ergonomics Science The ''Theoretical Issues in Ergonomics Science' ...
, blouses, formal
dress A dress (also known as a frock or a gown) is a garment traditionally worn by women or girls consisting of a skirt with an attached bodice (or a matching bodice giving the effect of a one-piece garment). It consists of a top piece that covers ...
es, high-fashion clothes,
lining Lining may refer to: * Lining (sewing), the process of inserting an inner layer of fabric, fur, or other material * Lining of paintings, the process of restoration paintings by attaching a new canvas to the back of the existing one * Brake linin ...
,
lingerie Lingerie (, , ) is a category of primarily women's clothing including undergarments (mainly brassieres), sleepwear, and lightweight robes. The choice of the word is often motivated by an intention to imply that the garments are alluring, fashio ...
,
pajama Pajamas (American English, US) or pyjamas (English in the Commonwealth of Nations, Commonwealth) (), sometimes colloquially shortened to PJs, jammies, jam-jams, or in South Asia night suits, are several related types of clothing worn as night ...
s,
robe A robe is a loose-fitting outer garment. Unlike garments described as capes or cloaks, robes usually have sleeves. The English word ''robe'' derives from Middle English ''robe'' ("garment"), borrowed from Old French ''robe'' ("booty, spoils" ...
s, dress suits, sun dresses, and traditional Asian clothing. Silk is also excellent for insect-proof clothing, protecting the wearer from
mosquito Mosquitoes (or mosquitos) are members of a group of almost 3,600 species of small flies within the family Culicidae (from the Latin ''culex'' meaning " gnat"). The word "mosquito" (formed by ''mosca'' and diminutive ''-ito'') is Spanish for "li ...
es and horseflies. Fabrics that are often made from silk include
satin A satin weave is a type of fabric weave that produces a characteristically glossy, smooth or lustrous material, typically with a glossy top surface and a dull back. It is one of three fundamental types of textile weaves alongside plain weave ...
,
charmeuse Charmeuse (), from the French word for female charmer, is a lightweight fabric woven with a satin weave, in which the warp threads cross over four or more of the backing (weft) threads. These float threads give the front of the fabric a smooth, ...
,
habutai Habutai (from the Japanese , literally "feather-two-layer", also spelled habotai or habutae) is one of the most basic plain weaves of silk fabric. While it was traditionally woven in Japan, most habutai is today woven in China. It is normally a lin ...
, chiffon,
taffeta Taffeta (archaically spelled taffety or taffata) is a crisp, smooth, plain woven fabric made from silk, cuprammonium rayons, acetate, and polyester. The word is Persian (تافته) in origin and means "twisted woven". As clothing, it is used in ...
, crêpe de chine,
dupioni Dupioni (also referred to as douppioni or dupion) is a plain weave silk fabric, produced using fine yarn in the warp and uneven yarn reeled from two or more entangled cocoons in the weft. This creates tightly woven yardage with a highly-lustrous ...
,
noil Noil refers to the short fibers that are removed during the combing process in spinning. These fibers are often then used for other purposes. Fibers are chosen for their length and evenness in specific spinning techniques, such as worsted. The ...
,
tussah Tussar silk (alternatively spelled as tussah, tushar, tassar, tussore, tasar, tussur, or tusser, and also known as (Sanskrit) ''kosa'' silk) is produced from larvae of several species of silkworms belonging to the moth genus '' Antheraea'', incl ...
, and
shantung Shandong ( , ; ; alternately romanized as Shantung) is a coastal province of the People's Republic of China and is part of the East China region. Shandong has played a major role in Chinese history since the beginning of Chinese civilizati ...
, among others.


Furniture

Silk's attractive lustre and drape makes it suitable for many furnishing applications. It is used for
upholstery Upholstery is the work of providing furniture, especially seats, with padding, springs, webbing, and fabric or leather covers. The word also refers to the materials used to upholster something. ''Upholstery'' comes from the Middle English word ...
, wall coverings, window treatments (if blended with another fiber),
rug Rug or RUG may refer to: * Rug, or carpet, a textile floor covering * Rug, slang for a toupée * Ghent University (''Rijksunversiteit Gent'', or RUG) * Really Useful Group, or RUG, a company set up by Andrew Lloyd Webber * Rugby railway station, N ...
s,
bedding Bedding, also known as bedclothes or bed linen, is the materials laid above the mattress of a bed for hygiene, warmth, protection of the mattress, and decorative effect. Bedding is the removable and washable portion of a human sleeping environm ...
, and wall hangings.


Industry

Silk had many industrial and commercial uses, such as in
parachute A parachute is a device used to slow the motion of an object through an atmosphere by creating drag or, in a ram-air parachute, aerodynamic lift. A major application is to support people, for recreation or as a safety device for aviators, who ...
s, bicycle
tire A tire (American English) or tyre (British English) is a ring-shaped component that surrounds a Rim (wheel), wheel's rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide Traction (engineering), t ...
s, comforter filling, and
artillery Artillery is a class of heavy military ranged weapons that launch munitions far beyond the range and power of infantry firearms. Early artillery development focused on the ability to breach defensive walls and fortifications during siege ...
gunpowder Gunpowder, also commonly known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. It consists of a mixture of sulfur, carbon (in the form of charcoal) and potassium nitrate (saltpeter). ...
bags.


Medicine

A special manufacturing process removes the outer
sericin Sericin is a protein created by ''Bombyx mori'' (silkworms) in the production of silk. Silk is a fibre produced by the silkworm in production of its cocoon. It consists mainly of two proteins, fibroin and sericin. Silk consists of 70–80% f ...
coating of the silk, which makes it suitable as non-absorbable
surgical suture A surgical suture, also known as a stitch or stitches, is a medical device used to hold body tissues together and approximate wound edges after an injury or surgery. Application generally involves using a needle with an attached length of threa ...
s. This process has also recently led to the introduction of specialist silk underclothing, which has been used for skin conditions including
eczema Dermatitis is inflammation of the Human skin, skin, typically characterized by itchiness, erythema, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become lichenification, thick ...
. New uses and manufacturing techniques have been found for silk for making everything from disposable cups to drug delivery systems and holograms.


Biomaterial

Silk began to serve as a
biomedical Biomedicine (also referred to as Western medicine, mainstream medicine or conventional medicine)
material for sutures in surgeries as early as the second century CE. In the past 30 years, it has been widely studied and used as a
biomaterial A biomaterial is a substance that has been engineered to interact with biological systems for a medical purpose, either a therapeutic (treat, augment, repair, or replace a tissue function of the body) or a diagnostic one. As a science, biomateria ...
due to its
mechanical strength The field of strength of materials, also called mechanics of materials, typically refers to various methods of calculating the stresses and strains in structural members, such as beams, columns, and shafts. The methods employed to predict the re ...
,
biocompatibility Biocompatibility is related to the behavior of biomaterials in various contexts. The term refers to the ability of a material to perform with an appropriate host response in a specific situation. The ambiguity of the term reflects the ongoing de ...
, tunable degradation rate, ease to load cellular growth factors (for example, BMP-2), and its ability to be processed into several other formats such as films, gels, particles, and scaffolds. Silks from ''Bombyx mori'', a kind of cultivated silkworm, are the most widely investigated silks. Silks derived from ''Bombyx mori'' are generally made of two parts: the silk fibroin fiber which contains a light chain of 25kDa and a heavy chain of 350kDa (or 390kDa) linked by a single disulfide bond and a glue-like protein,
sericin Sericin is a protein created by ''Bombyx mori'' (silkworms) in the production of silk. Silk is a fibre produced by the silkworm in production of its cocoon. It consists mainly of two proteins, fibroin and sericin. Silk consists of 70–80% f ...
, comprising 25 to 30 percentage by weight. Silk fibroin contains hydrophobic
beta sheet The beta sheet, (β-sheet) (also β-pleated sheet) is a common motif of the regular protein secondary structure. Beta sheets consist of beta strands (β-strands) connected laterally by at least two or three backbone hydrogen bonds, forming a g ...
blocks, interrupted by small hydrophilic groups. And the beta-sheets contribute much to the high mechanical strength of silk fibers, which achieves 740 MPa, tens of times that of poly(lactic acid) and hundreds of times that of
collagen Collagen () is the main structural protein in the extracellular matrix found in the body's various connective tissues. As the main component of connective tissue, it is the most abundant protein in mammals, making up from 25% to 35% of the whole ...
. This impressive mechanical strength has made silk fibroin very competitive for applications in biomaterials. Indeed, silk fibers have found their way into tendon tissue engineering, where mechanical properties matter greatly. In addition, mechanical properties of silks from various kinds of silkworms vary widely, which provides more choices for their use in tissue engineering. Most products fabricated from regenerated silk are weak and brittle, with only ≈1–2% of the mechanical strength of native silk fibers due to the absence of appropriate secondary and hierarchical structure,


Biocompatibility

Biocompatibility, i.e., to what level the silk will cause an immune response, is a critical issue for biomaterials. The issue arose during its increasing clinical use. Wax or silicone is usually used as a coating to avoid fraying and potential immune responses when silk fibers serve as suture materials. Although the lack of detailed characterization of silk fibers, such as the extent of the removal of sericin, the surface chemical properties of coating material, and the process used, make it difficult to determine the real immune response of silk fibers in literature, it is generally believed that sericin is the major cause of immune response. Thus, the removal of sericin is an essential step to assure biocompatibility in biomaterial applications of silk. However, further research fails to prove clearly the contribution of sericin to inflammatory responses based on isolated sericin and sericin based biomaterials. In addition, silk fibroin exhibits an inflammatory response similar to that of tissue culture plastic in vitro when assessed with human mesenchymal
stem cell In multicellular organisms, stem cells are undifferentiated or partially differentiated cells that can differentiate into various types of cells and proliferate indefinitely to produce more of the same stem cell. They are the earliest type o ...
s (hMSCs) or lower than collagen and PLA when implant rat MSCs with silk fibroin films in vivo. Thus, appropriate degumming and sterilization will assure the biocompatibility of silk fibroin, which is further validated by in vivo experiments on rats and pigs. There are still concerns about the long-term safety of silk-based biomaterials in the human body in contrast to these promising results. Even though silk sutures serve well, they exist and interact within a limited period depending on the recovery of wounds (several weeks), much shorter than that in tissue engineering. Another concern arises from biodegradation because the biocompatibility of silk fibroin does not necessarily assure the biocompatibility of the decomposed products. In fact, different levels of immune responses and diseases have been triggered by the degraded products of silk fibroin.


Biodegradability

Biodegradability Biodegradation is the breakdown of organic matter by microorganisms, such as bacteria and fungi. It is generally assumed to be a natural process, which differentiates it from composting. Composting is a human-driven process in which biodegradati ...
(also known as
biodegradation Biodegradation is the breakdown of organic matter by microorganisms, such as bacteria and fungi. It is generally assumed to be a natural process, which differentiates it from composting. Composting is a human-driven process in which biodegrada ...
)—the ability to be disintegrated by biological approaches, including bacteria, fungi, and cells—is another significant property of biomaterials. Biodegradable materials can minimize the pain of patients from surgeries, especially in tissue engineering, since there is no need for surgery in order to remove the implanted scaffold.. Wang et al. showed the in vivo degradation of silk via aqueous 3-D scaffolds implanted into Lewis rats.
Enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
s are the means used to achieve degradation of silk in vitro. Protease XIV from
Streptomyces griseus ''Streptomyces griseus'' is a species of bacteria in the genus ''Streptomyces'' commonly found in soil. A few strains have been also reported from deep-sea sediments. It is a Gram-positive bacterium with high GC content. Along with most other s ...
and α-chymotrypsin from bovine pancreases are two popular enzymes for silk degradation. In addition,
gamma radiation A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically s ...
, as well as
cell metabolism Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...
, can also regulate the degradation of silk. Compared with synthetic biomaterials such as
polyglycolide Polyglycolide or poly(glycolic acid) (PGA), also spelled as polyglycolic acid, is a biodegradable, thermoplastic polymer and the simplest linear, aliphatic polyester. It can be prepared starting from glycolic acid by means of polycondensation or ...
s and
polylactide Polylactic acid, also known as poly(lactic acid) or polylactide (PLA), is a thermoplastic polyester with backbone formula or , formally obtained by condensation of lactic acid with loss of water (hence its name). It can also be prepared by rin ...
s, silk is advantageous in some aspects of biodegradation. The acidic degraded products of polyglycolides and polylactides will decrease the pH of the ambient environment and thus adversely influence the metabolism of cells, which is not an issue for silk. In addition, silk materials can retain strength over a desired period from weeks to months on an as-needed basis, by mediating the content of
beta sheets The beta sheet, (β-sheet) (also β-pleated sheet) is a common motif of the regular protein secondary structure. Beta sheets consist of beta strands (β-strands) connected laterally by at least two or three backbone hydrogen bonds, forming a gen ...
.


Genetic modification

Genetic modification 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 technologies used to change the genetic makeup of cells, including t ...
of domesticated silkworms has been used to alter the composition of the silk. As well as possibly facilitating the production of more useful types of silk, this may allow other industrially or therapeutically useful proteins to be made by silkworms.


Cultivation

Silk
moth Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of w ...
s lay eggs on specially prepared paper. The eggs hatch and the caterpillars (silkworms) are fed fresh
mulberry ''Morus'', a genus of flowering plants in the family Moraceae, consists of diverse species of deciduous trees commonly known as mulberries, growing wild and under cultivation in many temperate world regions. Generally, the genus has 64 identif ...
leaves. After about 35 days and 4 moltings, the caterpillars are 10,000 times heavier than when hatched and are ready to begin spinning a cocoon. A straw frame is placed over the tray of caterpillars, and each caterpillar begins spinning a cocoon by moving its head in a pattern. Two glands produce liquid silk and force it through openings in the head called spinnerets. Liquid silk is coated in sericin, a water-soluble protective gum, and solidifies on contact with the air. Within 2–3 days, the caterpillar spins about of filament and is completely encased in a cocoon. The silk farmers then heat the cocoons to kill them, leaving some to
metamorphose Metamorphosis is a biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some insec ...
into moths to breed the next generation of caterpillars. Harvested cocoons are then soaked in boiling water to soften the sericin holding the silk fibers together in a cocoon shape. The fibers are then unwound to produce a continuous thread. Since a single thread is too fine and fragile for commercial use, anywhere from three to ten strands are spun together to form a single thread of silk.


Animal rights

As the process of harvesting the silk from the cocoon kills the larvae by boiling, sericulture has been criticized by animal welfare activists, including
People for the Ethical Treatment of Animals People for the Ethical Treatment of Animals (PETA; , stylized as PeTA) is an American animal rights nonprofit organization based in Norfolk, Virginia, and led by Ingrid Newkirk, its international president. PETA reports that PETA entities have ...
(PETA), who urge people not to buy silk items.
Mahatma Gandhi Mohandas Karamchand Gandhi (; ; 2 October 1869 – 30 January 1948), popularly known as Mahatma Gandhi, was an Indian lawyer, anti-colonial nationalist Quote: "... marks Gandhi as a hybrid cosmopolitan figure who transformed ... anti- ...
was critical of silk production because of his
Ahimsa Ahimsa (, IAST: ''ahiṃsā'', ) is the ancient Indian principle of nonviolence which applies to all living beings. It is a key virtue in most Indian religions: Jainism, Buddhism, and Hinduism.Bajpai, Shiva (2011). The History of India ...
(non-violent) philosophy, which led to the promotion of cotton and
Ahimsa silk Ahimsa silk (''ahiṃsā'': Sanskrit for 'nonviolence') is a method of nonviolent silk breeding and harvesting. Wild silk moths are bred, rather than the domestic variety. It allows the completion of the metamorphosis of the silkworm to its moth s ...
, a type of
wild silk Wild silks have been known and used in many countries from early times, although the scale of production is far smaller than that from cultivated silkworms. Silk cocoons and nests often resemble paper or cloth, and their use has arisen independent ...
made from the cocoons of wild and semi-wild silk moths.


See also

*
Art silk Artificial silk or art silk is any synthetic fiber which resembles silk, but typically costs less to produce. Frequently, "artificial silk" is just a synonym for rayon. When made out of bamboo viscose it is also sometimes called bamboo silk. Th ...
*
Bulletproofing Bulletproofing is the process of making an object capable of stopping a bullet or similar high velocity projectiles (e.g. shrapnel). The term bullet resistance is often preferred because few, if any, practical materials provide complete protectio ...
*
International Year of Natural Fibres International is an adjective (also used as a noun) meaning "between nations". International may also refer to: Music Albums * ''International'' (Kevin Michael album), 2011 * ''International'' (New Order album), 2002 * ''International'' (The T ...
* Mommes *
Rayon Rayon is a semi-synthetic fiber, made from natural sources of regenerated cellulose, such as wood and related agricultural products. It has the same molecular structure as cellulose. It is also called viscose. Many types and grades of viscose f ...
*
Sea silk Sea silk is an extremely fine, rare, and valuable fabric that is made from the long silky filaments or byssus secreted by a gland in the foot of pen shells (in particular ''Pinna nobilis''). The byssus is used by the clam to attach itself to t ...
*
Silk waste Silk waste includes all kinds of raw silk which may be unwindable, and therefore unsuited to the throwing process. Before the introduction of machinery applicable to the spinning of silk waste, the refuse from cocoon reeling, and also from silk w ...
* Sinchaw *
Spider silk Spider silk is a protein fibre spun by spiders. Spiders use their silk to make Spider web, webs or other structures, which function as sticky nets to catch other animals, or as nests or cocoons to protect their offspring, or to wrap up prey. ...


References


Citations


Bibliography

* * Hill, John E. (2004)
''The Peoples of the West from the Weilüe''
魏略 ''by Yu Huan'' 魚豢'': A Third Century Chinese Account Composed between 239 and 265 AD.'' Draft annotated English translation. Appendix E. * Hill, John E. (2009) ''Through the Jade Gate to Rome: A Study of the Silk Routes during the Later Han Dynasty, 1st to 2nd centuries CE''. BookSurge, Charleston, South Carolina. . * Magie, David (1924). ''Historia Augusta Life of Heliogabalus''. Loeb Classical Texts No. 140: Harvard University Press..


Further reading

* Feltwell, John (1990). ''The Story of Silk''. Alan Sutton Publishing. . * Good, Irene (December 1995). "On the Question of Silk in Pre-Han Eurasia". ''Antiquity''. Vol. 69, Number 266. pp. 959–968. * Kadolph, Sara J. (2007). ''Textiles'' (10th ed.). Upper Saddle River: Pearson Prentice Hall. pp. 76–81. * Kuhn, Dieter (1995). "Silk Weaving in Ancient China: From Geometric Figures to Patterns of Pictorial Likeness". ''Chinese Science''. 12. pp. 77–114. * * Ricci, G.; et al. (2004). "Clinical Effectiveness of a Silk Fabric in the Treatment of Atopic Dermatitis". ''British Journal of Dermatology''. Issue 150. pp. 127–131. * Sung, Ying-Hsing. 1637. "Chapter 2. Clothing materials". ''Chinese Technology in the Seventeenth Century – T'ien-kung K'ai-wu''. Translated and annotated by E-tu Zen Sun and Shiou-chuan Sun. Pennsylvania State University Press, 1966. Reprint: Dover, 1997. * Liu, Xinru (1996). ''Silk and Religion: An Exploration of Material Life and the Thought of People, AD 600–1200''. Oxford University Press. * Liu, Xinru (2010). ''The Silk Road in World History''. Oxford University Press. ; (pbk).


External links


References to silk by Roman and Byzantine writersHistory of traditional silk in martial arts uniforms
*
physorg.com Phys.org is an online science, research and technology news aggregator offering briefs from press releases and reports from news agencies (a form of journalism sometimes pejoratively called churnalism). The website also produces its own science ...
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