Silk films are highly transparent at THz frequencies, so metamaterial silk composites display a strong resonant electromagnetic response. Each fabricated sample was 1 square centimeter and contained 10,000 metamaterial resonators with unique resonant response at the desired frequencies.
According to Fiorenzo Omenetto, the research team likens the concept to "a very peculiar kind of antennaactually, a lot of small antennas that behave as one. The silk metamaterial composite is sensitive to the dielectric properties of the silk substrate and can monitor the interaction between the silk and the local environment. For example, the metamaterial might signal changes in a bioreactive silk substrate that has been doped with proteins or enzymes."
The addition of a pure biological substrate such as silk to the gold metamaterial adds immense latitude and opportunity for unforeseen applications, says Professor Richard Averitt, one of Omenetto's collaborators from Boston University and an expert on metamaterials.
The resonance response could be used as an implantable electromagnetic signature for contrast agents or bio-tracking applications, says co-author Hu Tao, a former Boston University graduate student who is now a postdoctoral associate in Omenetto's lab.
In Situ Bio-Sensing
To demonstrate the concept, the researchers conducted a series of in vitro experiments that examined the electromagnetic response of the silk metamaterials when implanted under thin slices of muscle tissue. They found that the metamaterials retained their novel resonance properties while implanted. The same process could be readily adapted to fabricate silk metamaterials at other frequencies, according to Tao.
"Our approach offers great promise for applications such as in situ bio-sensing with implanted medical devices and the transmission of medical i
|Contact: Kim Thurler|