scholarly journals Incorporation of Proteins with Different Isoelectric Points into Biomimetic Ca-P Coatings: A New Approach to Produce Hybrid Coatings with Tailored Properties

2006 ◽  
Vol 309-311 ◽  
pp. 755-758 ◽  
Author(s):  
H.S. Azevedo ◽  
Isabel B. Leonor ◽  
Rui L. Reis
Keyword(s):  
Calcium Phosphate ◽  
Bovine Serum Albumin ◽  
Hybrid Coating ◽  
Hybrid Coatings ◽  
New Approach ◽  
Phosphate Ions ◽  
Preferential Interactions ◽  
Isoelectric Points ◽  
Different Characteristics ◽  
Positively Charged

This work aims to study the effect of incorporating proteins with different isoelectric points (pI) on the structure, composition and morphology of biomimetic calcium-phosphate (Ca-P) coatings. For that, bovine serum albumin (BSA) and lysozyme, having respectively acidic and basic pIs, were used as model proteins. It was observed that the incorporation of positively charged proteins, such as lysozyme, was able to significantly change the structure of the coatings, possibly due to the preferential interactions between the protein and negatively charged phosphate ions. These results indicated that proteins with different characteristics can be incorporated into biomimetic Ca-P coatings in order to obtain a hybrid coating and at the same tailoring their properties.

Diamond Machinable Sol-Gel Silica Based Hybrid Coatings for High Precision Optical Molds

2010 ◽  
Vol 438 ◽  
pp. 65-72 ◽  
Author(s):  
Andreas Mehner ◽  
Ju An Dong ◽  
Timo Hoja ◽  
Torsten Prenzel ◽  
Yildirim Mutlugünes ◽  
...  
Keyword(s):  
Injection Molding ◽  
High Precision ◽  
Sol Gel ◽  
Processing Parameters ◽  
Hybrid Coatings ◽  
Optical Elements ◽  
Optical Components ◽  
New Approach ◽  
Free Silica ◽  
Gel Processing

The demand for high precision optical elements as micro lens arrays for displays increases continually. Economic mass production of such optical elements is done by replication with high precision optical molds. A new approach for manufacturing such molds was realized by diamond machinable and wear resistant sol-gel coatings. Crack free silica based hybrid coatings from base catalyzed sols from tetraethylorthosilicate (TEOS: Si(OC2H5)4) and methyltriethoxysilane (MTES: Si(CH3)(OC2H5)3) precursors were deposited onto pre-machined steel molds by spin coating process followed by a heat treatment at temperatures up to 800°C. Crack-free multilayer coatings with a total thickness of up to 18 µm were achieved. Micro-machining of these coatings was accomplished by high precision fly cutting with diamond tools. Molds with micro-structured coatings were successfully tested for injection molding of PMMA optical components. The wear resistance of the coatings was successfully tested by injection molding of 1000 PMMA lenses. Hardness and elastic modulus of the coatings were measured by nano indentation. The chemical composition was measured by X-ray photo electron spectroscopy (XPS) as a function of the sol-gel processing parameters.

Study of Bio-Mineralization of BCP with Compensation of Calcium and Phosphate Ions

2009 ◽  
Vol 610-613 ◽  
pp. 1391-1394
Author(s):  
Hua De Zheng ◽  
Ying Jun Wang ◽  
Qiang Ma ◽  
Cheng Yun Ning ◽  
Xiao Feng Chen
Keyword(s):  
Free Energy ◽  
Calcium Phosphate ◽  
Calcium Ions ◽  
Biphasic Calcium Phosphate ◽  
Porous Ceramic ◽  
Apatite Layer ◽  
Apatite Formation ◽  
Phosphate Ions

In the present study, an Intelligent Multi-parameter Simulated Evaluation in vitro （IMSE system） was used to study the deposition properties of apatite formation on the surface of biphasic calcium phosphate porous ceramic (BCP) from static and dynamic r-SBF. Results showed that apatite formed on the surface of BCP from static and dynamic r-SBF differed between each other. In static r-SBF, ions were transferred by diffusion, which could not compensate the consuming of calcium ions, and mist apatite layer was formed on the surface of samples. But in the dynamic r-SBF, simulated fluid was adjusted precisely and flowed forcedly, the concentrations of ions were homogeneous; with the compensation of ions, calcium and phosphate were supersaturated, and the free energy of apatite formation was negative, bone-like apatite sheets were formed on the surface of samples.

The Rebinding Properties of Bovine Serum Albumin Imprinted Calcium Phosphate/Polyacrylate/Alginate Hybrid Polymer Microspheres

2010 ◽  
Vol 152-153 ◽  
pp. 1636-1640 ◽  
Author(s):  
Kong Yin Zhao ◽  
Jun Fu Wei ◽  
Jin Yang Zhou ◽  
Yi Ping Zhao ◽  
Guo Xiang Cheng
Keyword(s):  
Calcium Phosphate ◽  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Bovine Serum ◽  
Polymer Microspheres ◽  
Hybrid Polymer ◽  
Ph Values ◽  
Factors Influencing ◽  
Recognition Property ◽  
Template Protein

Calcium phosphate/polyacrylate/alginate hybrid polymer microspheres with bovine serum albumin (BSA) embedded and coated on the surface were prepared with (NH4)2HPO4, sodium polyacrylate (SPA) and sodium alginate (SA) via Ca2+ crosslinking in inverse suspension. Rebinding behaviors of the microspheres were evaluated. The factors influencing the imprinting efficiency (IE) of imprinted microspheres were also studied, including the concentration of CaCl2, template content and pH values in rebinding solutions. Selectivity tests showed that the imprinted microspheres exhibited good recognition property for the template protein.

Microfiltration performance: physicochemical aspects of whey pretreatment

1995 ◽  
Vol 62 (2) ◽  
pp. 269-279 ◽  
Author(s):  
Genevieve Gesan ◽  
Georges Daufin ◽  
Uzi Merin ◽  
Jean-Pierre Labbe ◽  
Auguste Quemerais
Keyword(s):  
Calcium Phosphate ◽  
Membrane Surface ◽  
Physicochemical Process ◽  
High Shear ◽  
Lower Content ◽  
Phosphate Ions ◽  
Complex Lipid ◽  
Ionic Calcium ◽  
Calcium Phosphate Particles ◽  
Soluble Calcium

SUMMARYClarification of whey by microfiltration (MF) can be achieved after appropriate pretreatment of the feed. A control pretreatment consists of a physicochemical process comprising increased ionic calcium and pH accompanied by heat (50 °C, 15 min) to cause aggregation of complex lipid–calcium phosphate particles, which are then separated by MF. This pretreatment process was modified by increasing the temperature to 55 °C and by maintaining the pH constant during heat treatment. This modification resulted in larger calcium phosphate particles and a lower content of soluble calcium and phosphate ions. As a consequence, a longer period of MF operation, better whey clarification and lower calcium and phosphate content of the filtrate were achieved. This suggests that a loosely structured deposit was formed on the membrane surface which was less resistant to filtration than that resulting from the control pretreatment. During MF, it was necessary to avoid zones of high shear in the retentate compartment that might cause physical alteration of the aggregates.

scholarly journals Detection of Posner's clusters during calcium phosphate nucleation: a molecular dynamics study

2017 ◽  
Vol 5 (35) ◽  
pp. 7274-7284 ◽  
Author(s):  
Giulia Mancardi ◽  
Carlos Ernesto Hernandez Tamargo ◽  
Devis Di Tommaso ◽  
Nora H. de Leeuw
Keyword(s):  
Molecular Dynamics ◽  
Calcium Phosphate ◽  
Molecular Dynamics Simulations ◽  
Aggregation Process ◽  
Phosphate Ions ◽  
Dynamics Simulations

Molecular dynamics simulations of calcium and phosphate ions in water show that Posner-like clusters originate during the aggregation process.

scholarly journals New Analytical Approach for the Determination of Calcium Phosphate Dibasic and Tribasic in Processed Food by Comparison of Ion Chromatography with High-Performance Liquid Chromatography

Foods ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 248 ◽  
Author(s):  
Minjung Song ◽  
Juhee Park ◽  
Jihyun Lee ◽  
Heejae Suh ◽  
Hyunjung Lee ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Calcium Phosphate ◽  
Ion Chromatography ◽  
High Performance ◽  
Food Additives ◽  
Food Samples ◽  
Hplc Method ◽  
Processed Foods ◽  
Phosphate Ions

An analytical method to measure solubilized orthophosphate ions (HPO42− and PO43− ) from the water-insoluble food additives calcium phosphate dibasic (DCP) and calcium phosphate tribasic (TCP) in processed foods was optimized by comparing ion chromatography (IC) coupled with DS6 conductivity detector (Cond.) and high-performance liquid chromatography (HPLC) with Evaporative light scattering detector (ELSD) methods. The ion-pairing HPLC method could analyze calcium and phosphate ions successively. However, this method exhibited low reproducibility after approximately 48 hours of measurements. The IC method was established as an effective method of measuring orthophosphate ions with high reproducibility using distilled water and KOH solution as the mobile phase with a Dionex column. Matrix-based limit of detections (LOD) and limit of quantifications (LOQ) for snacks and cereals were estimated in the range of 0.01–0.91 µg/mL and 0.21–2.74 µg/mL, respectively. In inter-day and intra-day tests, the calculated precision (%RSD) and accuracy (recovery %) ranged from 0.5% to 6.6% and 82% to 117%, respectively, in both food samples. The levels of DCP or TCP could be analyzed in various positive food samples, and the developed IC method demonstrated good applicability in the analysis of DCP and TCP in collected processed foods.

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