Conferences - Seminars

26MAR
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  Monday 26 March 2018 13:15 - 14:15 MXF 1

Biogenic Scatterers, Mirrors, Multilayer Reflectors and Photonic Crystals. Futuristic Ancient Technologies

By Prof. Lia Addadi, Weizmann Institute of Science, Rehovot Israel

Organisms are able to construct an array of optical “devices” including diffuse scatterers, broadband reflectors, tunable photonic crystals and mirrors by varying the size, morphology and arrangement of organic crystals.
These “devices” perform a variety of optical functions, such as generating the white color of certain spiders, the metallic silvery reflectance of fish scales, the brilliant iridescent colors of some copepods, and mirrors used for vision in animal eyes. The copepods feature light-induced tunable photonic crystals. Scallops have tens of eyes, each containing a concave multi-layered mirror tiled with a seamlessly tiled mosaic of square guanine crystals. The mirror forms images on a double-layered retina. Shrimp, crayfish and lobsters possess compound eyes that also use reflective optics, and contain two sets of mirrors, composed of a previously unknown biogenic crystal – isoxanthopterine. The two mirrors have very different ultrastructures and functions that we can rationalize in terms of the optical performance of the eye. In all these examples, the hierarchical organization is controlled from the component crystals at the nanoscale to the complex 3D morphology at the millimeter level.
 
 
References:
 
D Gur, BA Palmer, S Weiner, L Addadi
Light Manipulation by Guanine Crystals in Organisms: Biogenic Scatterers, Mirrors, Multilayer Reflectors and Photonic Crystals
Adv Funct Mater, 1603514 (2017)
 
BA Palmer, GJ Taylor, V Brumfeld, D Gur, M Shemesh, N Elad, A Osherov, D Oron, S Weiner, L Addadi
The Image Forming Mirror in the Eye of the Scallop
Science, 358, 1172–1175 (2017)
 
Benjamin A. Palmer, Anna Hirsch, Vlad Brumfeld, Eliahu D. Aflalo, Iddo Pinkas, Amir Sagi, Shaked Rozenne, Dan Oron, Leslie Leiserowitz, Leeor Kronik, Steve Weiner and Lia Addadi
Isoxanthopterin: An Optically Functional Biogenic Crystal in the Eyes of Decapod Crustaceans
PNAS, in press (2018)
Bio: Lia Addadi is a Professor at the Weizmann Institute of Science in Rehovot, Israel. Her research spans the mechanisms of biomineralization, cell adhesion, and antibody recognition of organized materials, and has implications in areas as diverse as materials research, optics and medicine. Her laboratory (in collaboration with Steve Weiner’s) studies the interactions and cross talk between crystals and biological environment in biomineralization, spanning several orders of magnitude from the molecular level to the cell and tissue level. The aim is to unravel the strategies and design principles of the mineralized tissues, investigating them from their formation pathways to the architecture and finally to structure-function relations. Of particular interest is currently the research on how organisms manipulate light through complex crystalline architectures in plant leaves, in fish scales, crustacean cuticles and invertebrate eyes. Discovering similar pathways in widely different organisms raises fascinating questions about the material science advantages of the common solutions that evolved. Lia Addadi’s work has been recognized in numerous instances, including the Prelog Medal in Stereochemistry (1998), the 2009 Prize for Excellence from the Israel Chemical Society, the 2011 Aminoff Prize for Crystallography by the Swedish Royal Academy of Sciences, and the 2017 election to the US Academy of Sciences.
 

Organization Esther Amstad & Vaso Tileli

Contact Esther Amstad & Vaso Tileli

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