Scientists have created an "invisibility cloak" - able to bend light around solid objects - out of silk.
At the moment the cloak only works for light outside the visible spectrum, in the terahertz band between radio and infrared. But its developers, at Boston University and Tufts University, believe that it could be made to work at far smaller wavelengths, possibly even including visible light, according to Discovery News.
The researchers hope it will have applications in medical science, as well as opening the possibility of making people or objects invisible.
The "metamaterial" is made of silk covered in tiny gold structures, each a tiny spiral known as a "split ring resonator" or SSR. SSRs have fascinating effects on light - they can absorb, or reflect, all the light at a given wavelength, or bend that light around an object. The silk metamaterial has 10,000 SSRs per square centimetre.
Normally, terahertz waves would pass through silk unaffected. But the new meta-silk resonated when the light struck it.
Since silk is "biocompatible" - it doesn't spark an immune reaction when implanted in the human body - the meta-silk can be used widely in medicine. Fiorenzo Omenetto, one of the Tufts researchers, told Discovery: "This is an unusual angle for a metamaterial because of silk's ability to interface with the human body."
While the researchers say it could be used for Harry Potter-style invisibility cloaks for whole people, the medical angle is its most promising one. Radiologists could cloak organs in the material, allowing them to see past to the hidden parts behind. It could also be used as a blood glucose sensor for diabetes sufferers: as the levels of glucose change, so will the metamaterial. The change can be transmitted as radio (or other) waves and detected by a mobile phone.
Last year, British researchers at Imperial College London and the University of Southampton were given a £4.9m (€6m) grant to investigate metamaterials and their possible applications in medicine, defence, security and communication.