The Growth of Calcium Phosphates on Hydroxyapatite Crystals. The Effect of Fluoride and Phosphonate

1978 ◽  
Vol 57 (5-6) ◽  
pp. 735-742 ◽  
Author(s):  
J.P. Barone ◽  
G.H. Nancollas
Keyword(s):  
Crystal Growth ◽  
Calcium Phosphate ◽  
Calcium Phosphates ◽  
Fluoride Ion ◽  
Dicalcium Phosphate Dihydrate ◽  
Phosphate Dihydrate ◽  
Phosphate Phase ◽  
Calcium Phosphate Phase ◽  
Basic Phase ◽  
Hydroxyapatite Crystals

The nature of the calcium phosphate phase which precipitates on hydroxyapatite seed crystals can be controlled by varying the HAP seed concentration. At low seed concentrations, dicalcium phosphate dihydrate (DCPD) is formed while at high seed levels a more basic phase precipitates. It has been found that fluoride ion increases the percentage of basic phase that crystallizes while ethylidenediphosphonic acid encourages the formation of DCPD. This behavior is explained by the competition between the nucleation of DCPD and the crystal growth on sites already present on the HAP seeds.

scholarly journals In situ luminescence analysis: a new light on monitoring calcium phosphate phase transitions

2017 ◽  
Vol 4 (7) ◽  
pp. 1157-1165 ◽  
Author(s):  
H. Terraschke ◽  
M. Rothe ◽  
A.-M. Tsirigoni ◽  
P. Lindenberg ◽  
L. Ruiz Arana ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Calcium Phosphate ◽  
Synchrotron Radiation ◽  
Calcium Phosphates ◽  
High Sensitivity ◽  
Luminescence Analysis ◽  
Biologically Relevant ◽  
Phosphate Phase ◽  
Calcium Phosphate Phase

In situ luminescence measurements allow monitoring the phase transitions of biologically relevant calcium phosphates with high sensitivity, independent of synchrotron radiation.

Seeded Growth of Calcium Phosphates: Effect of Different Calcium Phosphate Seed Material

1976 ◽  
Vol 55 (4) ◽  
pp. 617-624 ◽  
Author(s):  
G.H. Nancollas ◽  
J.S. Wefel
Keyword(s):  
Calcium Phosphate ◽  
Tricalcium Phosphate ◽  
Calcium Phosphates ◽  
Octacalcium Phosphate ◽  
Dicalcium Phosphate ◽  
Dicalcium Phosphate Dihydrate ◽  
Seeded Growth ◽  
Seed Crystals ◽  
Phosphate Dihydrate ◽  
Supersaturated Solutions

The growth of calcium phosphates on seed materials, dicalcium PhosPhate dihydrate (DCPD), tricalcium phosphate (TCP), octacalcium phosphate (OCP), and hydroxyapatite (HAP) in stable supersaturated solutions has been studied under conditions of pH and concentration for which the predominant phases are 1, DCPD, and II, HAP. All seed crystals are good nucleators for DCPD in system I, but, aside from HAP itself, only OCP will readily induce growth under condition II.

Evidence of calcium phosphate supersaturation in the loop of Henle

1996 ◽  
Vol 270 (4) ◽  
pp. F604-F613 ◽  
Author(s):  
J. R. Asplin ◽  
N. S. Mandel ◽  
F. L. Coe
Keyword(s):  
Calcium Phosphate ◽  
Calcium Concentration ◽  
Loop Of Henle ◽  
X Ray ◽  
Ion Interactions ◽  
Collecting Ducts ◽  
Phosphate Phase ◽  
Dietary Phosphate ◽  
Calcium Phosphate Phase

We have used published rat micropuncture data to construct a matrix of ion concentrations along the rat nephron. With an iterative computer model of known ion interactions, we calculated relative supersaturation ratios in all nephron segments. The collecting ducts and urine showed expected supersaturation with stone-forming salts. Fluid in the thin segment of the loop of Henle may be supersaturated with calcium carbonate and calcium phosphate under certain conditions. Because calculations cannot predict the actual course of crystallization, we made solutions to mimic, in vitro, presumed conditions in the loop of Henle. The solid phases that formed were analyzed by X-ray powder diffraction, electron microprobe, and infrared spectroscopy. All samples were identified as poorly crystallized or immature apatite. The descending limb of Henle's loop creates a unique condition as it extracts water but not sodium, bicarbonate, calcium, or phosphate, giving a calcium concentration at the bend of 3 mM, pH 7.4, and a phosphate concentration that varies from 0.8 to 48 mM, depending on parathyroid hormone and dietary phosphate. We conclude that conditions in the thin segment potentially could create a solid calcium phosphate phase, which may initiate nucleation of calcium oxalate salts in the collecting ducts, potentiating nephrolithiasis and nephrocalcinosis.

Constant composition study of crystal growth of dicalcium phosphate dihydrate. The influence of polyphosphates, phosphonates, and phytate

1988 ◽  
Vol 66 (9) ◽  
pp. 2181-2187 ◽  
Author(s):  
Zahid Amjad
Keyword(s):  
Crystal Growth ◽  
Phosphonic Acid ◽  
Structural Features ◽  
Dicalcium Phosphate Dihydrate ◽  
Constant Composition ◽  
Seed Crystals ◽  
Langmuir Adsorption ◽  
Inhibitor Complex ◽  
Phosphate Dihydrate ◽  
Mechanism Of Inhibition

The influence of inhibitors of varying functional groups on the crystal growth of calcium phosphate dihydrate (CaHPO4•2H2O, DCPD) on DCPD seed crystals at pH 6.00, 37 °C, has been studied using the constant composition technique. The inhibitors studied include: (a) polyphosphate (sodium pyrophosphate, sodium hexametaphosphate, SHMP), (b) phosphonates (nitrilotris(methylene phosphonic acid), NTMP; 1-hydroxyethylidene-1,1-diphosphonic acid, HEDP; ethylenediaminetetra (methylene phosphonic acid), ETMP; hexamethylenediaminetetra(methylene phosphonic acid), HMDP); and (c) myoinositol hexaphosphoric acid (phytic acid). The effect of these inhibitors on the growth kinetics have been studied at several inhibitor concentrations. The retarding effect of these inhibitors is discussed in relation to calcium–inhibitor complex formation on the DCPD seed crystals and the structural features of the inhibitor molecules. The fit of the Langmuir adsorption to experimental data supports a mechanism of inhibition through molecular adsorption of the inhibitor ions on the surface of growing crystals. Based upon the kinetic data, the overall order of inhibitors effectiveness is[Formula: see text]

The uptake of strontium by calcium phosphate phase formed at an elevated pH

1996 ◽  
Vol 204 (2) ◽  
pp. 363-370 ◽  
Author(s):  
S. Raičević ◽  
Ž Vuković ◽  
T. L. Lizunova ◽  
V. F. Komarov
Keyword(s):  
Calcium Phosphate ◽  
Phosphate Phase ◽  
Calcium Phosphate Phase

Stabilizing amorphous calcium phosphate phase by citrate adsorption

CrystEngComm ◽  
2014 ◽  
Vol 16 (10) ◽  
pp. 1864-1867 ◽  
Author(s):  
Yan Chen ◽  
Wenjia Gu ◽  
Haihua Pan ◽  
Shuqin Jiang ◽  
Ruikang Tang
Keyword(s):  
Calcium Phosphate ◽  
Amorphous Phase ◽  
Amorphous Calcium Phosphate ◽  
Surface Reaction ◽  
Phosphate Phase ◽  
Calcium Phosphate Phase

Citrate controls nucleation by association with a precursor amorphous phase, which inhibits the surface reaction for nucleation.

Rheological Properties of an Injectable Calcium Phosphate Bone Cement and their Relationship with the Phase Evolution

2007 ◽  
Vol 336-338 ◽  
pp. 1658-1661
Author(s):  
Jian Dong Ye ◽  
Xiu Peng Wang ◽  
Ying Jun Wang
Keyword(s):  
Calcium Phosphate ◽  
Bone Cement ◽  
Yield Stress ◽  
Invasive Surgery ◽  
Phase Evolution ◽  
Hydration Reaction ◽  
Dicalcium Phosphate Dihydrate ◽  
Non Invasive ◽  
Phosphate Dihydrate ◽  
Calcium Phosphate Bone Cement

An injectable calcium phosphate bone cement was prepared by combining amorphous calcium phosphate (ACP) and dicalcium phosphate dihydrate (DCPD) for use in non-invasive surgery in this work. The effect of the conserving time on the viscosity, yield stress and injectability of the calcium phosphate cement (CPC) pastes were studied. The results showed that as the conserving time of the pastes prolonged, the viscosity and the yield stress of the pastes increased exponentially, and the injectability of the pastes decreased. This resulted from the transformation of DCPD and ACP into hydroxyapatite via hydration reaction. The results also indicated that the pastes still exhibited good injectability in even 15 min after preparation of the CPC pastes.

Preparation of Calcium Phosphate Cement Utilizing Dicalcium Phosphate Dihydrate and Calcium Carbonate

2014 ◽  
Vol 608 ◽  
pp. 280-286
Author(s):  
Nudthakarn Kosachan ◽  
Angkhana Jaroenworaluck ◽  
Sirithan Jiemsirilers ◽  
Supatra Jinawath ◽  
Ron Stevens
Keyword(s):  
Calcium Carbonate ◽  
Calcium Phosphate ◽  
Calcium Phosphate Cement ◽  
Raw Materials ◽  
Setting Time ◽  
Dicalcium Phosphate ◽  
Dicalcium Phosphate Dihydrate ◽  
Cement Pastes ◽  
Setting Times ◽  
Phosphate Dihydrate

Calcium phosphate cement has been widely used as a bone substitute because of its chemical similarity to natural bone. In this study, calcium phosphate cement was prepared using dicalcium phosphate dihydrate (CaHPO4.2H2O) and calcium carbonate (CaCO3) as starting raw materials. The cement pastes were mixed and the chemistry adjusted with two different aqueous solutions of sodium hydroxide (NaOH) and disodium hydrogen phosphate (Na2HPO4). Concentrations of the solution were varied in the range 0.5 to 5.0 mol/L with the ratio of solid/liquid = 2 g/ml. The cement paste was then poured into a silicone mold having a diameter of 10 mm and a height 15 mm. Setting times for the cement were measured using a Vicat apparatus. XRD, FT-IR, and SEM techniques were used to characterize properties and microstructure of the cement. From the experimental results, it is clear that different concentrations of Na2HPO4 and NaOH have affected the setting times of the cement. The relationship between concentration of NaOH and Na2HPO4 and setting time, including final properties of the cement, is discussed.

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