scholarly journals Diffusion-Controlled Crystallization of Calcium Phosphate in a Hydrogel toward a Homogeneous Octacalcium Phosphate/Agarose Composite

ACS Omega ◽  
2021 ◽  
Author(s):  
Yu Seob Shin ◽  
Min-kyung Jo ◽  
Young Shin Cho ◽  
Sung Ho Yang
Keyword(s):  
Calcium Phosphate ◽  
Octacalcium Phosphate ◽  
Diffusion Controlled ◽  
Controlled Crystallization

scholarly journals Microwave-Assisted Fabrication of Mesoporous Silica-Calcium Phosphate Composites for Dental Application

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 53
Author(s):  
Adrian Szewczyk ◽  
Adrianna Skwira ◽  
Marta Ginter ◽  
Donata Tajer ◽  
Magdalena Prokopowicz
Keyword(s):  
Calcium Phosphate ◽  
Mesoporous Silica ◽  
Octacalcium Phosphate ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Coating Solution ◽  
X Ray ◽  
Microwave Assisted ◽  
Calcium Orthophosphates ◽  
Different Types

Herein, the microwave-assisted wet precipitation method was used to obtain materials consisting of mesoporous silica (SBA-15) and calcium orthophosphates (CaP). Composites were prepared through immersion of mesoporous silica in different calcification coating solutions and then exposed to microwave radiation. The composites were characterized in terms of molecular structure, crystallinity, morphology, chemical composition, and mineralization potential by Fourier-transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), and scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (SEM-EDX). The application of microwave irradiation resulted in the formation of different types of calcium orthophosphates such as calcium deficient hydroxyapatite (CDHA), octacalcium phosphate (OCP), and amorphous calcium phosphate (ACP) on the SBA-15 surface, depending on the type of coating solution. The composites for which the progressive formation of hydroxyapatite during incubation in simulated body fluid was observed were further used in the production of final pharmaceutical forms: membranes, granules, and pellets. All of the obtained pharmaceutical forms preserved mineralization properties.

Two-Stage Crystallization Of Poly (Ether Ether Ketone) And Its Blends With Poly (Ether Imide)

1993 ◽  
Vol 321 ◽  
Author(s):  
Hsin-Lung Chen ◽  
Roger S. Porter
Keyword(s):  
Crystallization Rate ◽  
Primary Crystallization ◽  
Secondary Crystallization ◽  
Comparable Rate ◽  
Diffusion Controlled ◽  
Crystallization Region ◽  
Ether Ether Ketone ◽  
Poly Ether Ether Ketone ◽  
Controlled Crystallization ◽  
Ether Ketone

ABSTRACTThermal Mechanical analysis (TMA) has been used to study the crystallization behavior of poly (ether ether ketone) (PEEK) and its blends with poly (ether imide) (PEI). The two crystallization stages of PEEK are clearly distinguished by measuring the variation of film thickness with time during isothermal crystallization. Upon blending with PEI, the distinction of the two PEEK crystallization stages becomes obscure. This is attributed to the depressions in both nucleation density and spherulite growth rate upon blending with PEI.An Avrami analysis, Modified by considering both primary and secondary crystallization, is used to extract the respective kinetic behavior of these two crystallization stages. The results indicate that the secondary crystallization proceeded slower than the primary crystallization in the diffusion-controlled crystallization region. On the other hand, these two crystallization stages proceeded at comparable rate in the thermodynamically-controlled crystallization region. It is also found in the diffusion-controlled crystallization that blending with PEI induced a larger depression in the secondary crystallization rate than in the primary crystallization rate. Explanations for these observations are proposed and discussed.

Osteoconductive Property of a Mechanical Mixture of Octacalcium Phosphate and Amorphous Calcium Phosphate

2014 ◽  
Vol 6 (24) ◽  
pp. 22602-22611 ◽  
Author(s):  
Kazuhito Kobayashi ◽  
Takahisa Anada ◽  
Takuto Handa ◽  
Naofumi Kanda ◽  
Mariko Yoshinari ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Amorphous Calcium Phosphate ◽  
Octacalcium Phosphate ◽  
Mechanical Mixture ◽  
Osteoconductive Property

scholarly journals Phosphoserine Functionalized Cements Preserve Metastable Phases, and Reprecipitate Octacalcium Phosphate, Hydroxyapatite, Dicalcium Phosphate, and Amorphous Calcium Phosphate, during Degradation, In Vitro

2019 ◽  
Vol 10 (4) ◽  
pp. 54 ◽  
Author(s):  
Joseph Lazraq Bystrom ◽  
Michael Pujari-Palmer
Keyword(s):  
Calcium Phosphate ◽  
Amorphous Calcium Phosphate ◽  
Octacalcium Phosphate ◽  
Ionic Concentration ◽  
Strong Adhesion ◽  
Acidic Conditions ◽  
Rapid Transformation ◽  
Comparable Mass

Phosphoserine modified cements (PMC) exhibit unique properties, including strong adhesion to tissues and biomaterials. While TTCP-PMCs remodel into bone in vivo, little is known regarding the bioactivity and physiochemical changes that occur during resorption. In the present study, changes in the mechanical strength and composition were evaluated for 28 days, for three formulations of αTCP based PMCs. PMCs were significantly stronger than unmodified cement (38–49 MPa vs. 10 MPa). Inclusion of wollastonite in PMCs appeared to accelerate the conversion to hydroxyapatite, coincident with slight decrease in strength. In non-wollastonite PMCs the initial compressive strength did not change after 28 days in PBS (p > 0.99). Dissolution/degradation of PMC was evaluated in acidic (pH 2.7, pH 4.0), and supersaturated fluids (simulated body fluid (SBF)). PMCs exhibited comparable mass loss (<15%) after 14 days, regardless of pH and ionic concentration. Electron microscopy, infrared spectroscopy, and X-ray analysis revealed that significant amounts of brushite, octacalcium phosphate, and hydroxyapatite reprecipitated, following dissolution in acidic conditions (pH 2.7), while amorphous calcium phosphate formed in SBF. In conclusion, PMC surfaces remodel into metastable precursors to hydroxyapatite, in both acidic and neutral environments. By tuning the composition of PMCs, durable strength in fluids, and rapid transformation can be obtained.

Conversion of octacalcium phosphate in calcium phosphate cements

2000 ◽  
Vol 52 (1) ◽  
pp. 95-106 ◽  
Author(s):  
Erna A. P. De Maeyer ◽  
Ronald M. H. Verbeeck ◽  
Chris W. J. Vercruysse
Keyword(s):  
Calcium Phosphate ◽  
Octacalcium Phosphate ◽  
Calcium Phosphate Cements

In Vitro Study Bioactivity of HA/UHMWPE Nanocomposites

2007 ◽  
Vol 342-343 ◽  
pp. 701-704
Author(s):  
Li Ming Fang ◽  
Yang Leng ◽  
Ping Gao
Keyword(s):  
Molecular Weight ◽  
Calcium Phosphate ◽  
Simulated Body Fluid ◽  
Body Fluid ◽  
In Vitro Study ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Octacalcium Phosphate ◽  
Tof Sims ◽  
Ultrahigh Molecular Weight

Bioactivity of hydroxyapatite reinforced ultrahigh molecular weight polyethylene (HA/UHMWPE) nanocomposites with HA volume content of 10~50 % was evaluated by simulated body fluid (SBF) immersion. The effect of HA content on the capability for calcium phosphate (Ca- P) induction was studied. It was found that Ca-P deposition covered the whole surface of the composite with 30 vol. % of HA after immersion for 1 day and the layer grew to around 10 0m thick in one-week immersion, while there was few nucleus formed for composites with HA content lower than 30 vol. % after one-week immersion. The Ca-P structure was identified as octacalcium phosphate (OCP) by SEM, TEM, and ToF-SIMS.

scholarly journals Ammonium-to-sodium ion-exchange process at the interlayer of octacalcium phosphate

RSC Advances ◽  
2021 ◽  
Vol 11 (62) ◽  
pp. 39503-39507
Author(s):  
Yuki Sugiura ◽  
Yoji Makita ◽  
Masanori Horie
Keyword(s):  
Calcium Phosphate ◽  
Ion Exchange ◽  
Exchange Process ◽  
Octacalcium Phosphate ◽  
Sodium Ion ◽  
Ionic Exchange ◽  
Ion Exchange Process

Octacalcium phosphate (OCP) has been considered as the layer component of calcium phosphate, but whether it achieves the ionic-exchange ability of conventional layer components is unclear. In this study, we demonstrated the evidence of ionic exchange process at the interlayer of OCP.

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