Scientists use spider silk instead of fiber-optic sensors to help search for Mars life

A research team funded by the European Space Agency used spider silk instead of traditional optical fibers to make optical sensors that can be used to search for trace gases produced by biological processes. This is good news for scientists looking for possible life on Mars. They have always hoped to have a device that can detect small amounts of ammonia released by microbial metabolism while being insensitive to the large amount of carbon dioxide in the Martian atmosphere.

The team leader, Luc Twanaz of the Federal Institute of Technology in Lausanne, Switzerland, said that traditional fibers are made of quartz glass, and their chemical inertness makes them difficult to be good chemical sensors, and the optical properties of spider silk can pass. The chemical substance has been greatly modified. The presence of certain molecules can cause hydrogen bond cleavage in the spider's molecules, which causes polarization changes in the passing beam, but this only applies to polar molecules (molecular charge distribution asymmetry), such as ammonia; non-polar Molecules such as carbon dioxide do not cause a reaction.

Twananaz and his team tested the tow of the female spider. According to a recent report by the Journal of the Institute of Electrical and Electronics Engineers, they found that spider silk fibers can transmit light beams including visible light and infrared light at a wavelength of up to about 1400 nm. Among them, 900 nm wavelength infrared light is best transmitted, and the fiber loss is 4 decibels per cm. Although it is much higher than the silica fiber loss, this value can be reduced to 0.2 decibels per cm, which is enough for the field of inductive measurement. .

Tavanaz said that there are more practical applications for this spider sensor, such as monitoring industrial processes or as automotive sensors, because they do not need to be replaced regularly like sensors that rely on irreversible chemical processes. He hopes to create a measurement database that maps the changes in the beam to the relevant chemicals. He believes that the sensitivity of the sensor can be improved by using rayon or by doping other chemicals in the spider silk.

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