Doping Uric Acid Crystals. 2. Anhydrous Uric Acid

Zellelow, Amanuel Z.; Cox, Kristin A.; Fink, Dorothy A.; Ford, Catherine; Kim, Kun-Hae; Sours, Ryan E.; Swift, Jennifer A.

doi:10.1021/cg1005055

Cited by 12 publications

(13 citation statements)

References 9 publications

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“…The first studies on uric acid crystallization in the presence of colorants began in the 1930s, when Gaubert examined crystals grown in the presence of various synthetic dyes. Kleeberg added to this body of work with additional dye studies in the 1970s. , More recent work in our lab has shown that low concentrations of a wide variety of neutral and cationic dyes can be included in UA and UAD , often with high specificity. ,− When a cationic dye is included, charge-balance can be achieved by the parallel inclusion of a urate ion. For example, methylene blue (and several other dyes) is selectively included in {001} and {201} growth sectors of UA .…”

Section: Resultsmentioning

confidence: 99%

“…Kleeberg added to this body of work with additional dye studies in the 1970s. , More recent work in our lab has shown that low concentrations of a wide variety of neutral and cationic dyes can be included in UA and UAD , often with high specificity. ,− When a cationic dye is included, charge-balance can be achieved by the parallel inclusion of a urate ion. For example, methylene blue (and several other dyes) is selectively included in {001} and {201} growth sectors of UA . In contrast, methylene blue is included throughout the UAD crystals .…”

Section: Resultsmentioning

confidence: 99%

“…The UA-Ur inclusion crystals obtained typically exhibited either an hourglass or Maltese cross (X-shaped) pigmentation pattern (Figure ). The hourglass pattern in UA has been observed from growth in the presence of a number of different synthetic dyes . Preferred dye inclusion in the {001} and {201} growth sectors likely stems from kinetic factors, as the growth rate along the ± c -axis is significantly (10×) faster than along the ± b -axis .…”

Section: Resultsmentioning

confidence: 99%

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Urochrome Pigment in Uric Acid Crystals

et al. 2016

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Renal stones are heterogeneous composites of numerous microscopic crystals (e.g., calcium oxalate, calcium phosphate, uric acid, etc.) and 2–3 wt % amorphous organic “matrix”. Uric acid kidney stones are often red–orange–brown in color, though uric acid crystals are colorless. The stone color originates from a variety of components in the matrix, some of which are a broad range of urinary pigments or urochrome. Herein, we report the first definitive structure of one of these pigments, urorosein, and its ability to form intracrystalline inclusions in single crystals of both anhydrous uric acid and uric acid dihydrate. The preferred orientation of the included urorosein molecules in the uric acid crystals was determined through polarized light microspectroscopy. On the basis of these results, it seems likely that other urochrome pigments can locate in both intercrystalline and intracrystalline spaces in urinary precipitates. This expands the conventional picture of where “matrix” resides in these composite materials.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Urochrome Pigment in Uric Acid Crystals

et al. 2016

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“…In contrast, physiologic UA deposits can exhibit irregular morphologies and appear colored because of the inclusion of other biomolecules in the crystal lattice during growth. The first reports of UA crystallization in the presence of dye molecules appeared over a century ago. − We have since re-investigated the selective inclusion of several dyes − and urinary pigments in UA as well as the uric acid dihydrate phase.…”

Section: Results and Discusionmentioning

confidence: 99%

Molecular Crystal Mechanical Properties Altered via Dopant Inclusion

Liu

Hooks

et al. 2020

Chem. Mater.

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All molecular crystals contain defects, yet the effects these defects have on the material properties they exhibit are poorly understood. Here, the relationship between mechanical properties and defect concentration is established through nanoindentation studies on single crystals of uric acid (UA) with two different types of substitutional defects. Defects are intentionally created by preparing UA-dye crystals with two different dyes chosen to span either one or more than one molecular layer when included in the host matrix. The included dye concentrations in materials prepared from several welldefined growth conditions are then spectroscopically quantified. Sector-specific nanoindentation measurements on UA-dye crystals with dye concentrations ranging from 0.01 to 1 wt % illustrate two competing effects. UA-dye crystals with the lowest dye concentrations exhibited Young's moduli reductions of up to ∼50% compared to undoped crystals, with defects causing elastic softening. With progressively higher concentrations of defects spanning multiple UA layers, a second competing material stiffening effect is activated. At the concentrations necessary for material strengthening to occur, twinning and other morphological changes are also observed, suggesting that the macroscopic changes are likely related to efforts to reduce lattice strain. The magnitude of the property changes realized illustrates the potential of defect engineering to tune mechanical properties and may be especially beneficial in systems where increased plasticity is desired.

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“…A key point of this discussion is the birefringence nature of the compound associated with the metallic-like structural color of these beetles [30,31,32,33,34,35], which should be deposited within the chitin structure. There are many reports of doping or functionalized uric acid [48,49,50,51,52], but not all of them present a birefringence [48]. The chemical extraction of the PCOC sample was attempted by using the method suggested by Caveney [38].…”

Section: Resultsmentioning

confidence: 99%

Photonic Crystal Characterization of the Cuticles of Chrysina chrysargyrea and Chrysina optima Jewel Scarab Beetles

et al. 2018

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A unified description involving structural morphology and composition, dispersion of optical constants, modeled and measured reflection spectra and photonic crystal characterization is devised. Light reflection spectra by the cuticles of scarab beetles (Chrysina chrysargyrea and Chrysina optima), measured in the wavelength range 300–1000 nm, show spectrally structured broad bands. Scanning electron microscopy analysis shows that the pitches of the twisted structures responsible for the left-handed circularly polarized reflected light change monotonically with depth through the cuticles, making it possible to obtain the explicit depth-dependence for each cuticle arrangement considered. This variation is a key aspect, and it will be introduced in the context of Berreman’s formalism, which allows us to evaluate reflection spectra whose main features coincide in those displayed in measurements. Through the dispersion relation obtained from the Helmholtz’s equation satisfied by the circular components of the propagating fields, the presence of a photonic band gap is established for each case considered. These band gaps depend on depth through the cuticle, and their spectral positions change with depth. This explains the presence of broad bands in the reflection spectra, and their spectral features correlate with details in the variation of the pitch with depth. The twisted structures consist of chitin nanofibrils whose optical anisotropy is not large enough so as to be approached from modeling the measured reflection spectra. The presence of a high birefringence substance embedded in the chitin matrix is required. In this sense, the presence of uric acid crystallites through the cuticle is strongly suggested by frustrated attenuated total reflection and Raman spectroscopy analysis. The complete optical modeling is performed incorporating the wavelength-dependent optical constants of chitin and uric acid.

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Doping Uric Acid Crystals. 2. Anhydrous Uric Acid

Cited by 12 publications

References 9 publications

Urochrome Pigment in Uric Acid Crystals

Urochrome Pigment in Uric Acid Crystals

Molecular Crystal Mechanical Properties Altered via Dopant Inclusion

Photonic Crystal Characterization of the Cuticles of Chrysina chrysargyrea and Chrysina optima Jewel Scarab Beetles

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