Nexia Biotechnologies Tried to Make Spider Silk from Goat Milk
For almost two decades, scientists pursued a method for producing spider silk through goat milk. Nexia Biotechnologies inserted genes associated with silk production into genetically modified goats, aiming to make the animals secrete the relevant proteins through their mammary glands.
The company selected milk as a production route because a goat’s mammary gland can continuously release substantial quantities of protein. The project redirected that biological process towards a fibre whose properties include strength, elasticity and resistance across very high and very low temperatures. Spider silk is also biocompatible, which drew interest in possible sutures, implants and other medical devices, as well as clothing, food-related uses and protective equipment.
Ali Alwattari, a materials scientist who had worked at Procter & Gamble on polymers for products including nappies, joined the effort. The operation included goats from different breeds, sizes and backgrounds. Staff kept the animals relaxed with selected soundtracks, including reggae and rhythm and blues associated with the origins of particular groups.
Investor interest was substantial. Nexia raised $40m in its initial public offering in 2000, among the larger biotechnology fundraisings of that period. In 2002, the company’s president told The New York Times that the project represented a revolution. Goats associated with the silk programme appeared in newspapers and magazines.
In 2003, the researchers produced the first human-made mile of artificial silk, according to the account. The following year, however, the proteins extracted from the goats’ milk were found to be too short and weak to support production at scale. The practical reliance on live animals to make sophisticated fibres also proved unworkable. Mr Alwattari and Brad Cilley, Nexia’s vice-president of commercial development, left the company soon afterwards. Nexia declared bankruptcy in 2009.
The research continued after the company’s collapse. Molecular biologists Justin Jones and Randy Lewis transported about 20 remaining goats from Wyoming to Canada in a trailer and returned them to a laboratory. Other research groups later pursued the same protein using bacteria and fungi instead of goats. Two decades on, some researchers involved in engineered silk research say that improvements in technology, lower equipment costs and greater understanding of molecular genetics have addressed obstacles faced by Nexia. Demand for sustainable and biocompatible materials has also supported work aimed at medical uses and alternatives to plastics and synthetic fibres.
