SilkElastinResilin

Arjun K Gopi1St M.Sc BPSCbpst, kochi

Overview…

Silk :- Elastin :- Resilin :- Introduction Production Process Physical Properties Chemical Properties Uses

Introduction Properties Importance

Introduction Properties

Silk

Introduction :-

Silk is a natural protein fibre, some forms of which can be woven into textiles. The protein fibre of silk is composed mainly of fibroin and produced by certain insect larvae to form cocoons.[1]

 The best-known type of silk is obtained from the cocoons of the larvae of the mulberrysilkworm Bombyx mori reared in captivity (sericulture). The shimmering appearance of silk is due to the triangular prism-like structure of the silk fibre, which allows silk cloth to refract incoming light at different angles, thus producing different colours.

The construction of silk is called sericulture.

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.

Production process :-

Production process :-

Properties :-

Silk has a smooth, soft texture that is not slippery, unlike many synthetic fibers.

Silk is one of the strongest natural fibers but 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 will be weak if exposed to too much sunlight. It may also be attacked by insects, especially if left dirty.

Silk is a poor conductor of electricity and thus susceptible to static cling.

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.

Physical Properties

Chemical Properties

Silk emitted by the silkworm consists of two main proteins, sericin and fibroin, fibroin being the structural center of the silk, and serecin being the sticky material surrounding it. 

The high proportion (50%) of glycine, which is a small amino acid, allows tight packing and the fibers are strong and resistant to breaking. The 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 is resistant to most mineral acids, except for sulfuric acid, which dissolves it. It is yellowed by perspiration. Chlorine bleach will also destroy silk fabrics

Uses :-

 used for clothing such as shirts, ties, blouses, formal dresses, high fashion clothes, lining, lingerie, pajamas, robes, dress suits, sun dresses and Eastern folk costumes.

Silk's attractive lustre and drape makes it suitable for many furnishing applications. It is used for upholstery, wall coverings, window treatments (if blended with another fiber), rugs, bedding and wall hangings.

A special manufacturing process removes the outer irritant sericin coating of the silk, which makes it suitable as non-absorbable surgical sutures.

 New uses and manufacturing techniques have been found for silk for making everything from disposable cups to drug delivery systems and holograms

Elastin

Introduction :- Elastin is a protein in connective tissue that is elastic and allows many tissues in

the body to resume their shape after stretching or contracting. Elastin helps skin to return to its original position when it is poked or pinched.

Elastin is also an important load-bearing tissue in the bodies of vertebrates and used in places where mechanical energy is required to be stored. In humans, elastin is encoded by the ELN gene.

Can be stretched to several times their normal length, but recoil back.

Elastin is present in lungs, walls of large arteries, elastic ligaments.

 elastin is made of simple amino acids such as glycine, valine, alanine, and proline

Insoluble protein polymer.

Elastin is made by linking many soluble tropoelastin protein molecules, in a reaction catalyzed by lysyl oxidase, to make a massive insoluble, durable cross-linked array. The amino acid responsible for these cross-links is lysine.

defects in elastin include Marfan's Syndrome and emphysema caused by  α1-antitrypsin deficiency.

The most common external signs associated with Marfan syndrome include excessively long arms and legs, arm span being greater than height.

Properties :-

Elastin serves an important function in arteries as a medium for pressure wave propagation to help blood flow and is particularly abundant in large elastic blood vessels such as the aorta. Elastin is also very important in the lungs, elastic ligaments, the skin, and the bladder, elastic cartilage. It is present in all vertebrates above the jawless fish.

Importance :-

Resilin

Introduction :-

Resilin is an elastomeric protein found in many insects. It is part of what enables insects of many species to jump or pivot their wings efficiently. It was first discovered by Torkel Weis-Fogh in locust wing-hinges.

Resilin is currently the most efficient elastic protein, Because of its high strain, low stiffness, and high resilience.

 It does not have any regular structure but its randomly coiled chains are crosslinked by di- and tri-tyrosine links.

Resilin must last for the lifetime of adult insects and must therefore operate for hundreds of millions of extensions and contractions; its elastic efficiency ensures performance during the insect's lifetime. Resilin exhibits unusual elastomeric behaviour only when swollen in polar solvents such as water.

Properties :-  the superior mechanical properties of resilin, resilin-based proteins are

autofluorescent, display self-assembly properties, and undergo phase transitions in response to temperature.

These properties have potential application in designing biosensors or environmentally responsive materials for use in tissue engineering or drug delivery.

Furthermore, the capability of resilin-based biomaterials has been expanded by designing proteins that include both resilin-based sequences and bioactive domains such as cell-adhesion or matrix metalloproteinase sequences.

These new materials maintain the superior mechanical and physical properties of resilin and also have the added benefit of controlling cell response. Because the mechanical and biological properties can be tuned through protein engineering,