Crystal Growth Formation Research Articles

Review: Post-translational modifications of marine shell matrix proteins.

Shell matrix proteins (SMPs) are key components for the Mollusk shell biomineralization. SMPs function has been hypothesized in several proteins by bioinformatics analysis, and through in vitro crystallization assays. However, studies of the post-translational modifications (PTMs) of SMPs, which contribute to their structure and the function, are limited. This review provides the current status of the SMPs with the most common PTMs described (glycosylation, phosphorylation, and disulfide bond formation) and their role in shell biomineralization. Also, recent studies based on recombinant production of SMPs are discussed. Finally, recommendations for the study of SMPs and their PTMs are provided. The review showed that PTMs are widely distributed in SMPs, and their presence on SMPs may contribute to the modulation of their activity in some SMPs, contributing to the crystal growth formation and differentiation through different mechanisms, however, in a few cases the lack of the PTMs do not alter their inherent function.

An Aseptic One-Shot Bottom-Up Method To Produce Progesterone Nanocrystals: Controlled Size and Improved Bioavailability.

Progesterone (PG) is an essential sex hormone with a variety of important biological functions, but its insolubility leads to low bioavailability of most water-based formulations. What is more, the commercial oil-based formulations often cause severe side effects after long-term injection due to poor tissue absorption of oil. Herein, we report an aseptic bottom-up method utilizing emulsion freeze-drying technology that produces size-controllable, highly bioavailable, and water-based PG nanocrystal injection. The key factors that can determine the features of nanocrystals were investigated, including solvents, water-to-oil ratio, drug concentrations, type of surfactants, temperature in freeze-drying process, and lyoprotectants. Mechanisms of crystal growth formation process for PG nanocrystals were also analyzed theoretically. The prepared water-based PG nanocrystal suspension injection (PG/NSI) not only showed quick dissolution behaviors but also had significantly improved bioavailability in vivo. Therefore, this method can effectively control the size of nanocrystals, enhance bioavailability of insoluble drugs, and produce aseptic water-based nanocrystals that can be directly used for injection. Moreover, this method can also be used to prepare nanocrystals with the desired size under aseptic conditions for other poorly water-soluble drugs.

Effect of Ionic Liquid Additives on the Solubility Behavior and Morphology of Calcium Sulfate Dihydrate (Gypsum) in the Aqueous Sodium Chloride System and Physicochemical Solution Properties at 30 °C

We have investigated the solubility behavior of calcium sulfate dihydrate (gypsum, CaSO4·2H2O) in aqueous NaCl solutions upon the addition of ammonium- or imidazolium-based ionic liquids (ILs), viz., ethylammonium lactate (EAL), 1-ethyl-3-methyl imidazolium hydrogen sulfate ([C2mim]HSO4), and 1-butyl-3-methyl imidazolium hydrogen sulfate ([C4mim]HSO4) at 30 °C. The addition of ammonium lactate ILs increased solubility significantly, ∼500%, whereas the addition of imidazolium hydrogen sulfate ILs decreased the solubility by ∼60%. The addition of ILs shifted the solubility maximum of CaSO4·2H2O toward either higher or lower concentration of NaCl in solution depending on the nature of IL additive. Solution properties such as density (ρ) and speed of sound (u) have been measured for the quaternary systems (CaSO4·2H2O + NaCl + ILs + H2O) at 30 °C. Solution isentropic compressibility (κS) has been derived from measurements of u and ρ. Physical and derived properties have been fitted with suitable polynomial equations. Crystal growth formation and surface morphology of CaSO4·2H2O crystals recrystallized from different aqueous IL solutions have also been examined. IL additives have shown good potential for calcium sulfate scale removal and as calcium sulfate precipitation agent.

The influence of various physico-chemical process parameters on kinetics and growth mechanism of struvite crystallisation

In response to struvite formation problems in wastewater treatment plants (WWTP), this mechanistic growth kinetic study of struvite crystal (MgNH4PO4·6H2O) was undertaken to determine the cause of preferential accumulation and to provide the remediation information to the designer of WWTP. Struvite is the mineral phase of one of the urinary tract stones of human and animals also. Here the authors presented the struvite crystal growth formation kinetics mechanism under different physico-chemical process parameters such as supersaturation (Mg2+,NH4+,PO43-), solution pH, stirrer speed, temperature, impurities and seeding conductions. To measure the growth rate of struvite crystals and to identify its various dependence system parameters, laboratory measurements were conducted in an isothermal batch 1l stirred seeded crystalliser. Supersaturation and pH have been found to be the most influential parameters for struvite crystallisation. It was found that growth rate increased with an increase in solution pH in the pH range of 8–9. The rate of change of ortho-phosphate concentration in the bulk solution increases with increasing supersaturation ratio. The growth rate increased with increase in temperature. Higher NaCl salt concentration and higher speed also produced higher struvite growth kinetics. Fundamentally struvite crystal formation followed a classical diffusion–reaction mass transfer mechanism and overall mass transfer coefficients (KL) under various physico-chemical process parameters have been determined. The kinetic rate constants were also calculated by fitting a first-order kinetic model and power law model to the experimental data obtained. It was also found that there was increase in product crystal size with increase in solution pH, stirrer speed and amount of salts due to slow nucleation followed by fast growth process. Struvite crystallisation may also have implication in an alternative sustainable and economical recovery of phosphorous from concentrated waste water stream.

Cystone, a well-known herbal formulation, inhibits struvite crystal growth formation in single diffusion gel growth technique

Objective: The present study was aimed to evaluate the beneficial effect of Cystone® against struvite crystal growth in in vitro conditions. Methods: Various concentrations of Cystone® was prepared in 1 M magnesium acetate solution and evaluated for crystal growth inhibition assay by a well-known method called single diffusion gel growth technique in vitro. Results: Cystone®, a well-known polyherbal formulation, at 0.5, 1 and 2% concentrations showed significant and dose-dependent inhibition of struvite crystal growth formation in in vitro by reducing number, total mass and total volume of the struvite crystals formed and also caused fragmentation of grown struvite crystals in the gel matrix. Conclusion: The results of the present study indicate, Cystone® significantly retards the formation of struvite stones and also brings about its fragmentation. This could be one of the probable mechanisms behind the beneficial effect offered by Cystone® in the clinical management of urolithiasis and urinary tract infections.

Na-doped hydroxyapatite coating on carbon/carbon composites: Preparation, in vitro bioactivity and biocompatibility

Na-doped hydroxyapatite (Na-HA) coating was directly prepared onto carbon/carbon (C/C) composites using electrochemical deposition (ECD) and the mean thickness of the coating is approximately 10±2μm. The formed Na-HA crystals which are Ca-deficient, are rod-like with a hexagonal cross section. The Na/P molar ratios of the coating formed on C/C substrate is 0.097. During the deposition, the Na-HA crystals grow in both radial and longitudinal directions, and faster along the longitudinal direction. The pattern formation of crystal growth leads to dense coating which would help to increase the bonding strength of the coating. The average shear bonding strength of Na-HA coating on C/C is 5.55±0.77MPa. The in vitro bioactivity of the Na-HA coated C/C composites were investigated by soaking the samples in a simulated body fluid (SBF) for 14days. The results indicate that the Na-HA coated C/C composites can rapidly induce bone-like apatite nucleation and growth on its surface in SBF. The in vitro cellular biocompatibility tests reveal that the Na-HA coating was better to improve the in vitro biocompatibility of C/C composites compared with hydroxyapatite (HA) coating. It was suggested that the Na-HA coating might be an effective method to improve the surface bioactivity and biocompatibility of C/C composites.

Effect of A-zeolite on the crystallization behavior ofIn-situ polymerized poly(ethylene terephthalate) (PET) nanocomposites

The crystallization behavior and fine structure of poly(ethylene terephthalate) (PET)/A-zeolite nanocomposites were assessed via differential scanning calorimetry (DSC) and time-resolved small-angle X-ray scattering (TR-SAXS). The Avrami exponent increased from 3.5 to approximately 4.5 with increasing A-zeolite contents, thereby indicating a change in crystal growth formation. The rate constant,k, evidenced an increasing trend with increases in A-zeolite contents. The SAXS data revealed morphological changes occurring during isothermal crystallization. As the zeolite content increased, the long period and amorphous region size also increased. It has been suggested that, since PET molecules passed through the zeolite pores, some of them are rejected into the amorphous region, thereby resulting in increased amorphous region size and increased long period, respectively. In addition, as PET chains piercing into A-zeolite pores cannot precipitate perfect crystal folding, imperfect crystals begin to melt at an earlier temperature, as was revealed by the SAXS profiles obtained during heating. However, the spherulite size was reduced with increasing nanofiller content, because impingement between adjacent spherulites in the nanocomposite occurs earlier than that of homo PET, due to the increase in nucleating sites.

Hyperbranched Polyesters with Carboxylic or Sulfonic Acid Functional Groups for Crystallization Modification of Calcium Carbonate

AbstractHyperbranched aliphatic polyesters functionalized with carboxylic or sulfonic acid groups have been synthesized and employed as crystallization modifiers for calcium carbonate. The functionalized polyesters exhibit remarkable polymorph selectivity and morphology control. Stable spherical vaterite particles of diameter less than 10 µm with narrow size distribution were easy to produce on a large scale. With an increase in the concentration and monomer/core ratio of the polyester, the vaterite content increases accordingly with promoted morphology control to monodisperse spheres. The CaCO3 concentration and the initial pH can also influence the morphology and polymorphism of the produced calcium carbonate. Under certain conditions, well‐defined core‐shell structured vaterite spheres are obtained with obvious radial organization by nano‐aggregation of about 70 ± 10 nm crystallites, which may mediate and combine the nano‐aggregation and crystal growth formation mechanism of vaterite polymorph.magnified image

Growth of calcium phosphate on poling treated ferroelectric BaTiO 3 ceramics

Barium titanate (BaTiO 3; BTO) is ferroelectric and piezoelectric after poling treatment. In this study, the bioactivity of BTO was investigated after a poling treatment by examining the formation of crystal growth on specimen surfaces in vitro. Negatively charged BTO surfaces showed calcium phosphate (Ca-P) crystal growth, while deposition of sodium chloride was observed on the positively charged BTO surfaces. After 30 days immersion in Eagle’s MEM, the thickness of Ca-P crystal on negatively charged BTO surfaces increased to 0.8–0.9 μm. These data indicate that incorporating selectively polarized BTO on implant surfaces is a promising means for improving the bioactivity of implant materials.

Historical aspects of crystal growth technology

The father of crystal fabrication technology is A. Verneuil with his flame-fusion growth method 1902. His principles of nucleation and growth control are adapted in most later growth methods from melt. The Czochralski method was essentially developed by Teal, Little and Dash. The multidisciplinary nature of crystal growth and epitaxy technology and the complex multiparameter processes, and also the scaling problem, have impeded the scientific development of this important area. Only recently it was possible to solve the striation problem and to understand the control of epitaxial growth modes for achieving structurally perfect layers of GaAs and high- T c superconductors with atomically flat surfaces. The formation of crystal growth and epitaxy engineers and scientists as well as centers of excellence are necessary in order to develop crystal and epilayer fabrication technologies required for development of highest-efficiency white light-emitting diodes and photovoltaic solar cells for energy-saving lighting and as alternative source of energy. Also laser-fusion energy and other high technologies have to wait for progress in crystal growth technology.

Crystal growth formation processes of HNaMP2O7 crystals under hydrothermal conditions

New Na+ superionic conductors HNaMP2O7 (where M = Co, Ni, Zn, Mn, Cu, Pb or Fe) were obtained by hydrothermal methods at lower PT conditions (T = 250°C, P = 1000 Pa). The process of crystallization with respect to solute-solvent interactions and complexation have been studied. The crystals were characterized by X-ray diffraction (XRD), electron probe X-ray analysis (EPMA) and impedance spectroscopy.