Guanine-Based biogenic photonic-crystal arrays in fish and spiders

Avital Levy-Lior*, Eyal Shimoni, Osip Schwartz, Efrat Gavish-Regev, Dan Oron, Geoff Oxford, Steve Weiner, Lia Addadi

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

118 Scopus citations


Biological photonic systems composed of anhydrous guanine crystals evolved separately in several taxonomie groups. Here, two such systems found in fish and spiders, both of which make use of anhydrous guanine crystal plates to produce structural colors, are examined. Measurements of the photoniccrystal structures using cryo-SEM show that the crystal plates in both fish skin and spider integument are ∼20-nm thick. The reflective unit in the fish comprises stacks of single plates alternating with ∼ 230-nm-thick cytoplasm layers. In the spiders the plates are formed as doublet crystals, cemented by 30-nm layers of amorphous guanine, and are stacked with ∼200nm of cytoplasm between crystal doublets. They achieve light reflective properties through the control of crystal morphology and stack dimensions, reaching similar efficiencies of light reflectivity in both fish skin and spider integument. The structure of guanine plates in spiders are compared with the more common situation in which guanine occurs in the form of relatively unorganized prismatic crystals, yielding a matt white coloration.

Original languageAmerican English
Pages (from-to)320-329
Number of pages10
JournalAdvanced Functional Materials
Issue number2
StatePublished - 22 Jan 2010
Externally publishedYes


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