Genetically modified goats could soon produce milk loaded with spider silk tough enough to be used as body armour yet fine enough for medical sutures.

Researchers at Quebec-based Nexia Biotechnologies have produced spider silk in mammalian cell cultures and found a way to spin it.

Spiders produce one of the toughest biological materials in their webs. Nexia is developing its silk for medical, military and industrial markets.

Unlike silkworms, spiders have resisted domestication. So the researchers copied the genes spiders use to make silk and inserted the genes into cells taken from cow's udders and hamsters to test if the process worked.

In Friday's issue of the journal Science, the researchers report the cells produced the spider silk and they were able to squeeze it out.

Nexia president and chief executive officer Jeffrey Turner calls the product BioSteel. "Mimicking spider silk properties has been the Holy Grail of material science for a long time and now we've been able to make useful fibers," Turner said in a release.

The fine silk proteins were spun from an aqueous solution and are probably biodegradable, Turner said. Their next step is to make the silk in large amounts for commercial purposes.

The female genetically modified goats can act like silk protein factories when they give birth and start producing milk in February.

Nexia has an exclusive license to the spider silk genes and patents on the culturing, purifying and spinning systems. The Canadian Department of National Defence and the U.S. Army both helped fund the research.