Silk-based biomaterials have unique biophysical features that can be exploited to create optical sensors that could host “living” blood or pH indicators, and would biologically decompose after use in the human body. Biomedical engineers at Tufts University (Medford, MA) used all-aqueous processing of silk fibroin to create novel surface-nanopatterned protein materials with surface morphology controlled down to a scale of 125 nm. Professor Fiorenzo Omenetto and colleagues boiled cocoons of the Bombyx mori silkworm to extract a silk protein that was poured onto negative molds of diffraction gratings. After air-drying, the team found that sensitive biological “receptors” within the solution stayed active long after the solution hardened into gratings, pattern generators, holograms, and lenses. Biological components, such as hemoglobin and the enzyme peroxidase, incorporated into the silk optics could provide a combination of biochemical and optical readout in a single disposable, completely degradable element with spectral discrimination and biological function. The silk proteins could be used in a wide range of optical applications, from glucose monitoring, to bacteria sensing in food packaging. Contact Fiorenzo Omenetto at [email protected].