The beautiful, strong webs that spiders weave help them capture food and can make good cocoons. But spiders are not known for their expertise in electronics, fiber optics, and medical diagnostics. Until now.
Nolwenn Huby, a physicist at the Institut de Physique de Rennes, France, found that spider web silks are a natural at transmitting laser light. Just like fiber optic cable can transmit light and broadcast television images, detect tumors and other diseases, spider silk can transmit light (and the same information) on an integrated computer chip. Huby and her colleagues presented their findings at the Optical Society of America’s annual meeting recently.
The findings mean that spider silks could be used for medical imaging. Because spider silks are no wider than a human hair, they can shed light on very tight areas of the body that are now out of reach for fiber optic cables. In addition, spider silk devices could be implanted in the body—since silks are biodegradable and non-toxic, they could transmit diagnostic information and just be absorbed by the body when finished.
This research is the first known to look at the optical properties of spider silk. “When we first tested spider silk, we didn’t know what to expect,” Huby said. “We thought, ‘why not try this as an optical fiber to propagate light?”
There is a catch: spider silk still would need some chemical tweaking before it’s ready for industrial production. Spider silks, at least for now, depend entirely on the willingness of the spider. A similar silk, from the silkworm, could be scaled up, however, says Fiorenzo Omenetto, a biomedical engineer at Tufts University, who has worked with silkworm silk for years. Silkworm and spider silks share many properties—incredible strength, thin size, and optical transmission.
Omenetto is looking at the proteins that make up silkworm silk, in order to produce natural plastics that could be used in electronics. For example, he recently created a silk-based device that shoots a laser beam. This could be useful in diagnostics; as light waves pass through a blood sample, a sensor could detect how those light waves bounce off molecules in the blood.
Omenetto hopes that devices based on silk (spider or silkworm) may be available within a decade. “I like to think we threw a big stone in the pond. Hopefully, the waves will continue.”