A simple process turns cocoons into optical devices with biological applications.
Researchers led by Fiorenzo Omenetto of Tufts University are using silkworm proteins to develop novel deivces that have optical as well as sensory properties. Although a form of bio-utilization (the raw material is extract from silkworms), the processes to build the devices occur at ambient temperatures, allowing proteins to be incorporated.
After being purified and treated, the silk fibroin protein is formed in a nano-structured mold so that the device has the appropriate optical characteristics. By adding hemoglobin, oxygen can be detected by slight changes in the wavelength of light passing through the device. By adding specific enzymes and antibodies, other substances can be detected, such as glucose or tumor markers. Silk optical fibers could be used to both detect and transmit the resulting sensor signal. Since silk is biocompatible, the fibers can be incorporated during surgery - over time, they will dissolve.
Omenetto believes more sensitive sensors are possible by incorporating structural color inspired by the morpho butterfly, using appropriate nano-structured molds.