Spider silk: a new route for silk?

Silk, which naturally contains excellent structural and calorific properties, is the only continual thread found in nature. For a long time it has been sought after for its luxury and its numerous qualities. Light and naturally shiny, it is spun and dyed easily. Bourette silk, shantung, doupion, tussah, taffetas, grege silk: its various appearances change depending on its use. Previously used exclusively for the making of precious, heavily brocaded materials, always fashionable and highly reliable, it is used today in its pure and mixed form, for things as distinctive as technical underwear for sports.
Even though the main production of natural silk comes from the larva of the Bombyx Mori moth which, to weave its cocoon before transforming, produces a thread of continual silk, it is not the only source. There exist more than 400 species of silk making moths of which 80 are used for making “wild” silk.
However, more surprising still, the silk thread can also come from other animal species. For example the threads from the byssus of clams found in the Mediterranean have been used to make religious, ceremonial materials in Italy or more recently that of the red-legged golden orb-web spider found in Madagascar, which is today used for its great resistance and its golden yellow colour.
Since the 19th century, spider silk has been sought out for its exceptional qualities of lightness, resistance and elasticity. More resistant than steel and stretchier than nylon, it is both extremely stable and retains its shape. From the 17th century onwards, it was the Frenchman François Xavier Bon de Saint Hilaire who first wove a material from spider silk. In the 20th century however, its high production costs limit its cultivation.
In October 2011 a spectacular piece of golden yellow material was presented at the Chicago Institute of Art to celebrate the opening of its new gallery of African art, before being shown at the Victoria and Albert Museum in London in January 2012. Simon Peers and Nicholas Godley, who both live and work in Madagascar were inspired by illustrations from the 19th century to create this hand woven work which needed more than one million golden orb-web spider to make.
The mission to make the piece lasted four years: every morning, the spiders were collected from the surrounding nature and the specialised workers extracted the silk. Since then, the Madagascan society Madasilk, which offers a whole selection of artisanal silk threads for kitting, embroidery and weaving, has recently began the production and distribution of spider silk.
A subject of advanced research for the army and cutting edge technology, a number of efforts have been made to develop spider silk over the last century. Non-toxic and biodegradable, its production needs little energy but the cannibal character of the spider makes breeding them and any production on a commercial scale impossible. The principle aim is thus to synthetically reproduce it in industrial quantities and to give it exceptional qualities of fitness, strength and resistance – better than those of Kevlar silk- to try and apply them to the creation of modern textiles.
Over these past years, notably thanks to the progress in the domain of genetics, innovative approaches have been developed to try and reproduce spider silk. The first result is a hybrid silk produced by a transgenic silkworm. Similar to caseine in milk, silk is a protein fibre. Other experiments have also succeeded in the hybridisation of spider cells with those of a goat. The genetically modified goat was able to produce a milk which was used for the making a thread whose qualities were very close to those of spider silk.
Even more recently, the discovery of a bacteria capable of reproducing the proteins in spider silk opened up new possibilities and specialists predict that, in the near future, thanks to this bacteria, genetically modified plants will be able to produce a silk comparable to that of the spider which would be picked in the same way as cotton. All roads lead to silk.