scholarly journals Colour-producing β-keratin nanofibres in blue penguin ( Eudyptula minor ) feathers

2011 ◽  
Vol 7 (4) ◽  
pp. 543-546 ◽  
Author(s):  
Liliana D'Alba ◽  
Vinodkumar Saranathan ◽  
Julia A. Clarke ◽  
Jakob A. Vinther ◽  
Richard O. Prum ◽  
...  
Keyword(s):  
Self Assembly ◽  
Coherent Scattering ◽  
Two Dimensional ◽  
Collagen Fibres ◽  
Separation Processes ◽  
New Class ◽  
X Ray Scattering ◽  
Absorption Of Light ◽  
Physical Interactions ◽  
Living Organisms

The colours of living organisms are produced by the differential absorption of light by pigments (e.g. carotenoids, melanins) and/or by the physical interactions of light with biological nanostructures, referred to as structural colours. Only two fundamental morphologies of non-iridescent nanostructures are known in feathers, and recent work has proposed that they self-assemble by intracellular phase separation processes. Here, we report a new biophotonic nanostructure in the non-iridescent blue feather barbs of blue penguins ( Eudyptula minor ) composed of parallel β-keratin nanofibres organized into densely packed bundles. Synchrotron small angle X-ray scattering and two-dimensional Fourier analysis of electron micrographs of the barb nanostructure revealed short-range order in the organization of fibres at the appropriate size scale needed to produce the observed colour by coherent scattering. These two-dimensional quasi-ordered penguin nanostructures are convergent with similar arrays of parallel collagen fibres in avian and mammalian skin, but constitute a novel morphology for feathers. The identification of a new class of β-keratin nanostructures adds significantly to the known mechanisms of colour production in birds and suggests additional complexity in their self-assembly.

scholarly journals Controlling water evaporation through self-assembly

2016 ◽  
Vol 113 (37) ◽  
pp. 10275-10280 ◽  
Author(s):  
Kevin Roger ◽  
Marianne Liebi ◽  
Jimmy Heimdal ◽  
Quoc Dat Pham ◽  
Emma Sparr
Keyword(s):  
Self Assembly ◽  
Feedback Loop ◽  
Ambient Air ◽  
Underlying Mechanism ◽  
Water Evaporation ◽  
Air Humidity ◽  
X Ray ◽  
X Ray Scattering ◽  
Composition And Structure ◽  
Living Organisms

Water evaporation concerns all land-living organisms, as ambient air is dryer than their corresponding equilibrium humidity. Contrarily to plants, mammals are covered with a skin that not only hinders evaporation but also maintains its rate at a nearly constant value, independently of air humidity. Here, we show that simple amphiphiles/water systems reproduce this behavior, which suggests a common underlying mechanism originating from responding self-assembly structures. The composition and structure gradients arising from the evaporation process were characterized using optical microscopy, infrared microscopy, and small-angle X-ray scattering. We observed a thin and dry outer phase that responds to changes in air humidity by increasing its thickness as the air becomes dryer, which decreases its permeability to water, thus counterbalancing the increase in the evaporation driving force. This thin and dry outer phase therefore shields the systems from humidity variations. Such a feedback loop achieves a homeostatic regulation of water evaporation.

New Modular Calamitic Ligands for Self-Assembly of Thermostable Quantum Dot Microcapsules via Nematic Templating

2018 ◽  
Author(s):  
Amir Keshavarz ◽  
Sheida Riahinasab ◽  
Linda Hirst ◽  
Ben Stokes
Keyword(s):  
Quantum Dot ◽  
Self Assembly ◽  
Organic Ligands ◽  
Interparticle Spacing ◽  
Design Synthesis ◽  
X Ray ◽  
New Class ◽  
X Ray Scattering ◽  
Synthesis Properties ◽  
And Performance

The design, synthesis, properties, and performance of a new class of promesogenic calamitic side-tethering organic ligands used to direct quantum dot nanoparticle self-assembly via nematic templating are described. This work was motivated by inadequate modularity, step count, and yield associated with syntheses of existing ligands. Attaching the new ligands to quantum dots and dispersing them in a liquid crystal host affords hollow micron-sized capsules via nematic templating. The capsules resist thermal decomposition up to 350 °C — significantly higher than any previously reported microcapsules assembled from side-tethering calamitic ligand-functionalized nanoparticle. Evaluation of the capsules by small-angle X-ray scattering shows that interparticle spacing varies from 10–13 nm depending on the ligand used, and is correlated to aminoalkyl chain length.

New Modular Calamitic Ligands for Self-Assembly of Thermostable Quantum Dot Microcapsules via Nematic Templating

2018 ◽  
Author(s):  
Amir Keshavarz ◽  
Sheida Riahinasab ◽  
Linda Hirst ◽  
Ben Stokes
Keyword(s):  
Quantum Dot ◽  
Self Assembly ◽  
Organic Ligands ◽  
Interparticle Spacing ◽  
Design Synthesis ◽  
X Ray ◽  
New Class ◽  
X Ray Scattering ◽  
Synthesis Properties ◽  
And Performance

The design, synthesis, properties, and performance of a new class of promesogenic calamitic side-tethering organic ligands used to direct quantum dot nanoparticle self-assembly via nematic templating are described. This work was motivated by inadequate modularity, step count, and yield associated with syntheses of existing ligands. Attaching the new ligands to quantum dots and dispersing them in a liquid crystal host affords hollow micron-sized capsules via nematic templating. The capsules resist thermal decomposition up to 350 °C — significantly higher than any previously reported microcapsules assembled from side-tethering calamitic ligand-functionalized nanoparticle. Evaluation of the capsules by small-angle X-ray scattering shows that interparticle spacing varies from 10–13 nm depending on the ligand used, and is correlated to aminoalkyl chain length.

Effect of shape on the self-assembly of faceted patchy nanoplates with irregular shape into tiling patterns

Soft Matter ◽  
2015 ◽  
Vol 11 (7) ◽  
pp. 1386-1396 ◽  
Author(s):  
Jaime A. Millan ◽  
Daniel Ortiz ◽  
Sharon C. Glotzer
Keyword(s):  
Self Assembly ◽  
The Self ◽  
Irregular Shape ◽  
Two Dimensional ◽  
New Class ◽  
Wide Range ◽  
Two Dimensional Materials ◽  
Tiling Patterns

Recent reports of the synthesis and assembly of faceted nanoplates with a wide range of shapes and composition motivates the possibility of a new class of two-dimensional materials with specific patterns targeted for a host of exciting properties.

scholarly journals Coherent light scattering by nanostructured collagen arrays in the caruncles of the malagasy asities (Eurylaimidae: aves)

1999 ◽  
Vol 202 (24) ◽  
pp. 3507-3522 ◽  
Author(s):  
R.O. Prum ◽  
R. Torres ◽  
C. Kovach ◽  
S. Williamson ◽  
S.M. Goodman
Keyword(s):  
Power Spectra ◽  
Coherent Scattering ◽  
Reflectance Spectra ◽  
Two Dimensional ◽  
Collagen Fibres ◽  
Discrete Fourier Analysis ◽  
Near Ultraviolet ◽  
Avian Communication ◽  
Dark Blue ◽  
Prominent Peak

We investigated the anatomy, nanostructure and biophysics of the structurally coloured facial caruncles of three species in a clade of birds endemic to Madagascar (Philepittinae, Eurylaimidae: Aves). Caruncle tissues of all species had reflectance spectra with prominent, peak hues between 403 and 528 nm. Dark blue Neodrepanis tissues had substantial reflectance in the near ultraviolet (320–400 nm), which is visible to birds but not to humans, providing the first evidence of ultraviolet skin colours in birds and the first indications of the possible function of ultraviolet skin colours in avian communication. These structural colours are produced by coherent scattering from arrays of parallel collagen fibres in the dermis. Tissues of Philepitta castanea were organized into hexagonal, crystal-like arrays, whereas Neodrepanis tissues were quasiordered. Predictions of the peak hues of reflectance (λ (max)) using Bragg's law were relatively accurate, but Bragg's law requires physical assumptions that are obviously violated by these structures. A two-dimensional discrete Fourier analysis of the spatial variation in refractive index within the tissues documented that all the tissues are substantially nanostructured at the appropriate spatial scale to scatter visible light coherently. Predicted reflectance spectra based on the two-dimensional Fourier power spectra are relatively accurate at predicting the hue and shape of the reflectance spectra of the tissues. These results confirm that the nanostructure of the collagen arrays determines the colours that are coherently scattered by these tissues. The evolution of the anatomy and nanostructure of asity caruncles is discussed.

A Bottom-Up Approach to Solution-Processed, Atomically Precise Graphitic Cylinders on Surfaces

2018 ◽  
Author(s):  
Erik Leonhardt ◽  
Jeff M. Van Raden ◽  
David Miller ◽  
Lev N. Zakharov ◽  
Benjamin Aleman ◽  
...  
Keyword(s):  
Self Assembly ◽  
Carbon Nanostructures ◽  
Carbon Nanomaterials ◽  
Circle Packing ◽  
Pyrolytic Graphite ◽  
Building Blocks ◽  
Bottom Up ◽  
Casting Technique ◽  
New Class ◽  
Solution Casting Technique

Extended carbon nanostructures, such as carbon nanotubes (CNTs), exhibit remarkable properties but are difficult to synthesize uniformly. Herein, we present a new class of carbon nanomaterials constructed via the bottom-up self-assembly of cylindrical, atomically-precise small molecules. Guided by supramolecular design principles and circle packing theory, we have designed and synthesized a fluorinated nanohoop that, in the solid-state, self-assembles into nanotube-like arrays with channel diameters of precisely 1.63 nm. A mild solution-casting technique is then used to construct vertical “forests” of these arrays on a highly-ordered pyrolytic graphite (HOPG) surface through epitaxial growth. Furthermore, we show that a basic property of nanohoops, fluorescence, is readily transferred to the bulk phase, implying that the properties of these materials can be directly altered via precise functionalization of their nanohoop building blocks. The strategy presented is expected to have broader applications in the development of new graphitic nanomaterials with π-rich cavities reminiscent of CNTs.

In situ Time-Resolved Small-Angle X-ray Scattering Reveals the Formation Kinetics of Polyelectrolyte Complex Micelles

2019 ◽  
Author(s):  
Hao Wu ◽  
Jeffrey Ting ◽  
Siqi Meng ◽  
Matthew Tirrell
Keyword(s):  
Small Angle ◽  
Self Assembly ◽  
Electrostatic Interactions ◽  
Polyelectrolyte Complex ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Kinetics Of ◽  
Ray Scattering

We have directly observed the <i>in situ</i> self-assembly kinetics of polyelectrolyte complex (PEC) micelles by synchrotron time-resolved small-angle X-ray scattering, equipped with a stopped-flow device that provides millisecond temporal resolution. This work has elucidated one general kinetic pathway for the process of PEC micelle formation, which provides useful physical insights for increasing our fundamental understanding of complexation and self-assembly dynamics driven by electrostatic interactions that occur on ultrafast timescales.

New Methods for Analyzing Water Pollutants

1982 ◽  
Vol 14 (4-5) ◽  
pp. 59-71 ◽  
Author(s):  
L H Keith ◽  
R C Hall ◽  
R C Hanisch ◽  
R G Landolt ◽  
J E Henderson
Keyword(s):  
Amino Acids ◽  
Gas Chromatography ◽  
Two Dimensional ◽  
Gas Chromatograph ◽  
New Class ◽  
New Methods ◽  
System A ◽  
Drinking Waters ◽  
Computer Controlled ◽  
Nitrogen Containing Compounds

Two new methods have been developed to analyze for organic pollutants in water. The first, two-dimensional gas chromatography, using post detector peak recycling (PDPR), involves the use of a computer-controlled gas Chromatograph to selectively trap compounds of interest and rechromatograph them on a second column, recycling them through the same detector again. The second employs a new detector system, a thermally modulated electron capture detector (TMECD). Both methods were used to demonstrate their utility by applying them to the analysis of a new class of potentially ubiquitous anthropoaqueous pollutants in drinking waters- -haloacetonitriles. These newly identified compounds are produced from certain amino acids and other nitrogen-containing compounds reacting with chlorine during the disinfection stage of treatment.

scholarly journals Interfacial Crystallization and Supramolecular Self-Assembly of Spider Silk Inspired Protein at the Water-Air Interface

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4239
Author(s):  
Pezhman Mohammadi ◽  
Fabian Zemke ◽  
Wolfgang Wagermaier ◽  
Markus B. Linder
Keyword(s):  
Self Assembly ◽  
Spider Silk ◽  
Assembly Process ◽  
Protein Solution ◽  
Time Resolved ◽  
Macromolecular Assembly ◽  
X Ray Scattering ◽  
Air Interface ◽  
Fundamental Research ◽  
Β Sheet

Macromolecular assembly into complex morphologies and architectural shapes is an area of fundamental research and technological innovation. In this work, we investigate the self-assembly process of recombinantly produced protein inspired by spider silk (spidroin). To elucidate the first steps of the assembly process, we examined highly concentrated and viscous pendant droplets of this protein in air. We show how the protein self-assembles and crystallizes at the water–air interface into a relatively thick and highly elastic skin. Using time-resolved in situ synchrotron X-ray scattering measurements during the drying process, we showed that the skin evolved to contain a high β-sheet amount over time. We also found that β-sheet formation strongly depended on protein concentration and relative humidity. These had a strong influence not only on the amount, but also on the ordering of these structures during the β-sheet formation process. We also showed how the skin around pendant droplets can serve as a reservoir for attaining liquid–liquid phase separation and coacervation from the dilute protein solution. Essentially, this study shows a new assembly route which could be optimized for the synthesis of new materials from a dilute protein solution and determine the properties of the final products.

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