Building transistors from silk
Electronic components that can be put into the body are opening new paths for medical treatment, like gauging conditions and communicating with nerves. They’re not built from silicon or metals, but from flexible, biocompatible materials. Researchers at Linköping University are now demonstrating a transistor where the current is being conducted through silk fibres.
The research group in biomolecular and organic electronics previously designed electrochemical transistors and other components with textile fibres and strands of protein. In an article in the journal Advanced Materials, Professor Olle Inganäs and his co-workers show that thin silk fibres spun by the silkworm (Bombyx mori) provide better properties, not least for interaction with biological systems.
“We want to build electronic components into living tissue,” Inganäs says.
The technology is also useful in ‘smart clothing’ with built-in electronics, and soft screens for televisions and computers.
Normal electronics are based on metals and semiconductors, most often silicon. Here instead it is a plastic material, a conjugated polymer, that conducts the current. The silk fibres are dipped in a solution of this material, PEDOT-S, and can then be woven into different components.
The electrochemical transistor is an LiU discovery that works with both ions and electrons. Researchers laid two of the prepared silk fibres in a cross and placed a drop of electrolyte at the intersection. Through running a load over the ends of one fibre, they could control the current that arose in the other – the same function as a conventional transistor.
Two crossed silk fibres form the base of an electrochemical transistor. Source: Advanced Materials, n/a. doi: 10.1002/adma.201003601
Article: Woven electrochemical transistors on silk fibers by Christian Müller, Mahiar Hamedi, Roger Karlsson, Ronnie Jansson, Rebeca Marcilla, My Hedhammar and Olle Inganäs, Advanced Materials online 20 December 2010.
Last updated: 2011-02-09