A combination usually found in high fashion is now making (or breaking, bending or resonating; take your pick) waves in the metamaterials world - terahertz waves that is. Scientists have created a new metamaterial by stenciling thousands of gold split ring resonators (SRRs) onto silkworm silk. The resulting material can then render the item wrapped around it invisible - at least, to terahertz waves (for now).
In the journal Advanced Materials, Fiorenzo Omenetto, a scientist at Tufts University, details the new research on silk-based metamaterial done with colleagues at Boston University. They first started with a one-centimeter square piece of silkworm silk. They then etched 10,000 gold SRRs onto the material. SRRs is a common metamaterial structure that looks like a curly cue or short spiral and gives a material the ability to affect various waves. Upon exposure to terahertz waves, the scientists detected a resonance on the SSR-infused silk. Although currently the new metamaterial only works on the relatively long terahertz waves, they believe that it could also work as an invisibility cloak at smaller wavelengths, even the visible range.
Silk's inherent biocompatability gives it an edge over other metamaterials; unlike other metamaterials, silk won't be rejected by the human body when implanted. Hence the immediate thrust of Omenetto and his colleagues at Tufts in their research - biomedical applications. One possible use is an implantable glucose sensor for diabetics. The silk together with the metamaterial printed on it changes with the level of glucose in the blood. That change can then be relayed to a cellphone, giving the user a prick-less reading. The silk-based metamaterial may also allow medical personnel to cloak various organs or tissues and see through them, giving a better view of what's behind, Omentto says.
Via Discovery News