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SUMMARY:Biogenic light induced tuneable photonic crystals - Dvir Gur
DTSTART:20160519T130000Z
DTEND:20160519T140000Z
UID:TALK65447@talks.cam.ac.uk
CONTACT:31327
DESCRIPTION:DVIR GUR1\, BEN LESHEM2\, VIVIANA FARSTEY3\, DAN ORON2\, STEVE
  WEINER1 AND LIA ADDADI1\n1Weizmann Institute of Science\, Department of S
 tructural Biology and 2Dept. of Physics of Complex Systems\, Rehovot\, Isr
 ael. 3The Interuniversity Institute for Marine Sciences\, Eilat\, Israel.\
 n\nStrikingly brilliant structural colours using 2D or 3D arrays of chitin
  or cellulose fibers\, calcite or guanine crystals were independently evol
 ved by organisms to fulfil a variety of functions. Many of these optical s
 ystems are based on intra-cellular arrays of thin guanine crystal platelet
 s. \nThe silver iridescence of fish scales and skin\, as well as the brill
 iant blue colour of the neon tetra lateral stripe\, are both produced by c
 onstructive interference of light reflected from ordered arrays of guanine
  crystals separated one from the other by cytoplasm [1]\, [2]. \nCertain f
 amilies of marine crustacean copepods produce some of the most spectacular
  colours in nature. They produce different colours covering the whole visi
 ble spectrum\, and each colour is characterized by well-defined spectral c
 haracteristics. By combining correlative reflectance and cryo-electron mic
 roscopy image analyses\, together with optical time lapse recording and re
 flectance modelling\, we first showed that each colour is created by speci
 fic and precise cytoplasm spacings within stacks of uniformly thick guanin
 e crystals [3]. In addition\, the same organisms have the remarkable abili
 ty to change their reflectance spectrum in response to changes in the ligh
 t conditions. This change is reversible\, and is both intensity and wavele
 ngth dependent\, forming truly tuneable photonic crystal arrays [4]. \nThe
  insights gained from the understanding of how biology modulates reflectiv
 ity can provide inspiration for the design of artificial optical systems w
 ith properties yet hardly achievable\, if at all\, in artificial materials
 .\n\n1.	Gur\, D.\, Leshem\, B.\, Oron\, D.\, Weiner\, S.\, and Addadi\, L.
  (2014). The Structural Basis for Enhanced Silver Reflectance in Koi Fish 
 Scale and Skin. J. Am. Chem. Soc. 136\, 17236-17242.\n2.	Gur\, D.\, Palmer
 \, B.A.\, Leshem\, B.\, Oron\, D.\, Fratzl\, P.\, Weiner\, S.\, and Addadi
 \, L. (2015). The Mechanism of Color Change in the Neon Tetra Fish: a Ligh
 t-Induced Tunable Photonic Crystal Array. Angew Chem Int Edit 54\, 12426-1
 2430.\n3.	Gur\, D.\, Leshem\, B.\, Pierantoni\, M.\, Farstey\, V.\, Oron\,
  D.\, Weiner\, S.\, and Addadi\, L. (2015). Structural Basis for the Brill
 iant Colors of the Sapphirinid Copepods. J. Am. Chem. Soc. 137\, 8408-8411
 .\n4.	Gur\, D.\, Leshem\, B.\, Farstey\, V.\, Oron\, D.\, Weiner\, S.\, an
 d Addadi\, L. (2016): Light induced color change in the sapphirinid copepo
 ds: tunable photonic crystals. Adv.Func. Mat. DOI. 10.1002/adfm.201504339.
 \n\n\n
LOCATION:Unilever  Lecture Theatre\,  Department of Chemistry
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