Lia Addadi, Professor and Dorothy and Patrick E. Gorman Chair of Biological Ultrastructure Weizmann Institute of Science, Rehovot, Israel

Biogenic photonic crystals: ancient technologies for the future

The silver iridescence of fish scales and skin, as well as the brilliant blue colour of the neon tetra lateral stripe, and the spectacular colours of sapphirinid crustacean copepods are all produced by constructive interference of light reflected from ordered arrays of guanine crystals separated one from the other by cytoplasm. Combining correlative reflectance and cryo-electron microscopy, photonic band-gap modelling and crystallography, we rationalize the structure, the ultrastructural organization and the structure-function relations that produce structural colours in these organisms. The copepods have the remarkable ability to change their reflectance spectrum in response to changes in the light conditions, producing light-induced tuneable photonic crystal arrays. These properties are yet hardly achievable, if at all, in artificial materials.

Host: Associate professor Henrik Birkedal, iNANO & Department of Chemistry, Aarhus University