Structural Basis for the Brilliant Colors of the Sapphirinid Copepods

Gur, Dvir; Leshem, Ben; Pierantoni, M.; Farstey, Viviana; Oron, Dan; Weiner, Steve; Addadi, Lia

doi:10.1021/jacs.5b05289

Cited by 103 publications

(117 citation statements)

References 28 publications

(6 reference statements)

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“…The copepods possess multilayer reflectors underneath their chitin cuticle. [54][55][56] Correlative cryo-SEM and reflectance measurements showed that the males have the remarkable ability to reversibly change their reflectance spectrum in response to changes in the light conditions. [54][55][56] Correlative cryo-SEM and reflectance measurements showed that the males have the remarkable ability to reversibly change their reflectance spectrum in response to changes in the light conditions.…”

Section: Tunable Reflectorsmentioning

confidence: 99%

Light Manipulation by Guanine Crystals in Organisms: Biogenic Scatterers, Mirrors, Multilayer Reflectors and Photonic Crystals

Gur

Palmer

Weiner

2016

Adv Funct Materials

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145

197

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Guanine crystals are widely used in nature to manipulate light. The first part of this feature article explores how organisms are able to construct an extraordinary array of optical "devices" including diffuse scatterers, broadband and narrowband reflectors, tunable photonic crystals, and imageforming mirrors by varying the size, morphology, and arrangement of guanine crystals. The second part presents an overview of some of the properties of crystalline guanine to explain why this material is ideally suited for such optical applications. The high reflectivity of many natural optical systems ultimately derives from the fact that guanine crystals have an extremely high refractive index-a product of its anisotropic crystal structure comprised of densely stacked H-bonded layers. In order to optimize their reflectivity, many organisms exert exquisite control over the crystal morphology, forming platelike single crystals in which the high refractive index face is preferentially expressed. Guanine-based optics are used in a wide range of biological functions such as in camouflage, display, and vision, and exhibit a degree of versatility, tunability, and complexity that is difficult to incorporate into artificial devices using conventional engineering approaches. These biological systems could inspire the next generation of advanced optical materials. Figure 2. Examples of guanine crystal-based optical systems with different functionality, and their corresponding architecture. a-c) The white widow spider (Latrodectus pallidus):The integument of the spider (a) is white due to coherent scattering from a thick dense layer of blocky guanine crystals ≈1 µm in size (b), located beneath the integument. Impinging light is scattered multiple times from neighboring randomly distributed crystals (c) before emerging. d-f) The Japanese Koi fish (Cyprinus carpio). The silvery reflection of the fish (d) arises from disordered multilayer reflectors located in the epithelial layer underneath the scales of the fish (e). The thin (≈20 nm) plate-like guanine crystals are not all parallel to each other, but there is local order within each crystal stack. f) The cytoplasm spacings are widely distributed. Constructive interference of different wavelengths reflected from individual stacks results in diffuse broadband reflection, appearing silvery to the human eye (d, inset). g-i) The neon tetra fish (Paracheirodon innesi): The brilliant blue color of the lateral stripe of the neon tetra (g) arises from ordered, well aligned multilayer reflectors (h,i) with narrow distribution of thicknesses of both the thin guanine crystals (≈22 nm) and the thicker cytoplasm spacings (≈155 nm). Constructive interference of selected wavelengths reflected from individual stacks results in narrow band reflection centered at 500 nm (g, inset). j-l) The panther chameleon (Furcifer pardalis): The observed skin color of the panther chameleon (j) originates from a combination of both pigments and guanine-based 3D photonic crystals. Light is reflected from small ≈130 n...

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Section: Tunable Reflectorsmentioning

confidence: 99%

Light Manipulation by Guanine Crystals in Organisms: Biogenic Scatterers, Mirrors, Multilayer Reflectors and Photonic Crystals

Gur

Palmer

Weiner

2016

Adv Funct Materials

Self Cite

145

197

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“…The aragonite platelets are typically stacked and arrangements within the organic matrix ('columnar nacre') were reported as well as a 'brick-and-mortar'-like structure ('sheet nacre') [4]. Besides the superior mechanical performance, some biomaterials also display additional functionality that includes, for example, outstanding optical [13][14][15][16] or magnetic properties [17].…”

Section: Introductionmentioning

confidence: 99%

Gas barrier properties of bio-inspired Laponite–LC polymer hybrid films

et al. 2016

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Bio-inspired Laponite (clay) liquid crystal (LC) polymer composite materials with high clay fractions (>80%) and a high level of orientation of the clay platelets, i.e. with structural features similar to the ones found in natural nacre, have been shown to exhibit a promising behavior in the context of reduced oxygen transmission. Key characteristics of these bio-inspired composite materials are their high inorganic content, high level of exfoliation and orientation of the clay platelets, and the use of a LC polymer forming the organic matrix in between the Laponite particles. Each single feature may be beneficial to increase the materials gas barrier property rendering this composite a promising system with advantageous barrier capacities. In this detailed study, Laponite/LC polymer composite coatings with different clay loadings were investigated regarding their oxygen transmission rate. The obtained gas barrier performance was linked to the quality, respective Laponite content and the underlying composite micro-and nanostructure of the coatings. Most efficient oxygen barrier properties were observed for composite coatings with 83% Laponite loading that exhibit a structure similar to sheetlike nacre. Further on, advantageous mechanical properties of these Laponite/LC polymer composites reported previously give rise to a multifunctional composite system.

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“…In the past few years, theoretical and experimental interest in guanine multilayer reflectors was very high because of potential biomimetic applications (Bossard et al, 2016;Iwasaka et al, 2016;Hirsch et al, 2015;del Barco et al, 2015;Gur et al, 2015aGur et al, ,b, 2013 . Raman spectra of pigments from dark blue skin melanophores of panther chameleons (Teyssier et al, 2015) and red skin erythrophores of the lizard Phelsuma lineata (Saenko et al, 2013) exhibit two similar peaks, but the region around 1600 cm −1 is different.…”

Section: Tapetum Structurementioning

confidence: 99%

The ocelli of Archaeognatha (Hexapoda): Functional morphology, pigment migration and chemical nature of the reflective tapetum

Böhm

Pass

2016

Journal of Experimental Biology

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The ocelli of Archaeognatha, or jumping bristletails, differ from typical insect ocelli in shape and field of view. Although the shape of the lateral ocelli is highly variable among species, most Machiloidea have sole-shaped lateral ocelli beneath the compound eyes and a median ocellus that is oriented downward. This study investigated morphological and physiological aspects of the ocelli of Machilis hrabei and Lepismachilis spp. The lightreflecting ocellar tapetum in M. hrabei is made up of xanthine nanocrystals, as demonstrated by confocal Raman spectroscopy. Pigment granules in the photoreceptor cells move behind the tapetum in the dark-adapted state. Such a vertical pigment migration in combination with a tapetum has not been described for any insect ocellus so far. The pigment migration has a dynamic range of approximately 4 log units and is maximally sensitive to green light. Adaptation from darkness to bright light lasts over an hour, which is slow compared with the radial pupil mechanism in some dragonflies and locusts.

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Structural Basis for the Brilliant Colors of the Sapphirinid Copepods

Cited by 103 publications

References 28 publications

Light Manipulation by Guanine Crystals in Organisms: Biogenic Scatterers, Mirrors, Multilayer Reflectors and Photonic Crystals

Light Manipulation by Guanine Crystals in Organisms: Biogenic Scatterers, Mirrors, Multilayer Reflectors and Photonic Crystals

Gas barrier properties of bio-inspired Laponite–LC polymer hybrid films

The ocelli of Archaeognatha (Hexapoda): Functional morphology, pigment migration and chemical nature of the reflective tapetum

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