Scientists train bacteria to make spider silk
14 March 2005, MUNICH - Putting spiders out of a job, German scientists have trained bacteria to make cobwebs that they say will one day be spun into fine clothing or amazingly strong but light rope.
14 March 2005
MUNICH - Putting spiders out of a job, German scientists have trained bacteria to make cobwebs that they say will one day be spun into fine clothing or amazingly strong but light rope.
Biochemist Thomas Scheibel of the Technical University of Munich said the bacteria had been genetically modified to produce the best-yet spider silk, 20 percent as robust as genuine spider fibre.
Scheibel said science had been attempting for 30 years to make other organisms produce one of nature's most remarkable materials. Unlike silkworms, spiders themselves cannot be domesticated because they eat one another, making a spider farm impossible to organise.
The hope is to make stronger, lighter elastic materials that could replace plastics. Extremely thin sutures for eye or nerve surgery, plasters and other wound covers or artificial ligaments and tendons are among the possible uses.
Scheibel's work has been reviewed in the journal Microbial Cell Factories. He said the silk would be ideal to make paper for banknotes, since it could not be torn, or elastic panels for cars that could reacquire their old form after taking dents.
Spider silk has unusual tensile strength and is often described as being several times stronger than steel of the same thickness.
Before Scheibel, the best synthetic silks had a tensile strength of only 5 to 10 percent of the real thing.
"We are in talk with all sorts of industries to test our silk and develop industrial-scale production techniques," said Scheibel.
His team originally used a genetically altered virus to stimulate insect cells to make the proteins needed for silk. But it found this was not practical on an industrial scale. Other attempts elsewhere have modified goats, tobacco plants and potatoes to little avail.
"The yields were too low," said Scheibel. "And the fibres were far inferior to genuine spider silk."
Each of the 34,000 recognized species of spider has a specific "tool-kit" of silks with different properties, purposes and functions, explained the biochemistry professor. Most use more than one type of silk.
Scientists are especially interested in the silk used in spider draglines, the fibre that creates the main framework of a web that is able to stop a flying beetle going full tilt. Draglines also enable a spider to rapidly rappel to the floor to escape danger.
The research has adapted Escherichia coli, the common bacteria from the human gut, to produce the necessary proteins.
Subject: German news