Researchers in the Dept. of Biomedical Engineering at Tufts University have used a straightforward, water based extraction method to make pure, ultra-transparent silk films
. These films can be patterned with photonic devices, like diffraction gratings and infused with proteins and enzymes allowing biochemically active, cheap, printable optics to be fabricated. Applications to implantable optical sensors are almost limitless.
Disclaimer: I am part of this research group.