Spider silk will come handy for the making of airbags and bulletproof vests, among other things. After 15 years of study, biologists at the University of Wyoming, US, have cracked the code of this amazingly strong material, acquiring a better understanding of how the silk is made up of proteins. The researchers have determined the sequence of genes that produce the specific proteins. The knowledge will help them manufacture the same material artificially.

Spiders produce six different types of silks. With their spinnerets (major ampullate glands), the eight-legged animals apply physical force to rearrange the proteins' molecular structure into silk. The liquid silk turns solid in the air ' a process still found mysterious by scientists.

The tensile strength and natural elasticity of spider silk are much less than the easier-to-harvest silkworm silk. The former is three times harder than the high-performance synthetic fibres and five times stronger than steel ' if compared pound-for-pound.

Dr Randy Lewis, a professor of molecular biology who studied the genetic make-up of 34,000 different spider species, says, 'The lighter, tougher and more elastic fibres can be used to make ultra-fine surgical sutures, plasters and other wound covers, artificial ligaments and tendons, textiles for parachutes, protective clothing and body armour, ropes, fishing nets, and so on, in an environment-friendly way to replace plastics.'

Unlike silkworms, spiders tend to eat one another and cannot be effectively farmed. This compelled the scientists to search for alternative spider silk sources. For the time being they are introducing 'identified' silk-spider genes into other organisms (from simple bacteria to goats) for producing silk proteins that may later be used to create artificial silk threads.