Spin doctor

Machines that replicate the spinning action of spiders to produce man made spider-like silks five times stronger than steel and twice as elastic as nylon could be used to produce future medical implants.

According to Dr David Knight, a zoologist from Oxford Biomaterials, scientists have long been interested in spider silk. ‘It’s super-strong, super tough, and very stable at high temperatures. It can be made to conduct; it can be made magnetic and it’s ecologically friendly.’

The process by which spiders produce such a useful material using renewable materials at room temperature and low pressure is equally attractive, he said.

Knight was speaking at a recent meeting of the London Zoological Society devoted to biomimetics — an area of research that copies mechanisms from nature to create new materials and technologies.

He drew particular attention to the silk produced by the Golden Orb web spider. Its silk, six times stronger than high-tensile steel, five times tougher than Kevlar, and exceptionally elastic, is also biocompatible and thus highly desirable for a range of surgical applications.

The Golden Orb Web Spider, or Nephila maculata, is not the largest spider, but makes the largest and strongest web. It gets its name from the golden colour of its silk. The web can run from the top of a tree 6m high and up to 2m wide.

However, with less than a quarter of the spider’s silk protein genetically sequenced, nature is yet to give up the secrets of its properties.

Instead, a number of other silk-proteins are under the microscope — in particular those produced by silkworms. Knight explained that while the relative weakness of these silks is partly due to their protein structure, the clumsy spinning action of the silkworm is also a significant factor.

He claimed that by spinning these silks with a device that replicates the agility and elegance of a spider it should be possible to dramatically improve their properties. ‘If we avoid the figure-of-eight spinning action of a silkworm we should be able to get much better fibres out,’ he said.

Knight is working with German company Spintec on the development of such a machine. Although chief executive Dr Michael Reineker declined to reveal any details, he said that he hopes to make an announcement next year.

Meanwhile, Knight’s team has developed a relatively simple device that reels out silk without optimising the spinning conditions. He said that he has used the existing technique and commercially-available spider-like silks to make prototypes of a range of different implantable materials.

Future devices could include resorbable sutures, nerve regeneration devices, ligaments, tendons and bone graft materials.