Apatite Formation from Amorphous Calcium Phosphate and Mixed Amorphous Calcium Phosphate/Amorphous Calcium Carbonate

2016 ◽  
Vol 22 (35) ◽  
pp. 12347-12357 ◽  
Author(s):  
Casper J. S. Ibsen ◽  
Dmitry Chernyshov ◽  
Henrik Birkedal
Keyword(s):  
Calcium Carbonate ◽  
Calcium Phosphate ◽  
Amorphous Calcium Phosphate ◽  
Apatite Formation ◽  
Amorphous Calcium Carbonate

scholarly journals Pure hydroxyapatite synthesis originating from amorphous calcium carbonate

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Michika Sawada ◽  
Kandi Sridhar ◽  
Yasuharu Kanda ◽  
Shinya Yamanaka
Keyword(s):  
Calcium Carbonate ◽  
Calcium Phosphate ◽  
Room Temperature ◽  
Molar Ratio ◽  
Final Phase ◽  
Amorphous Calcium Carbonate ◽  
Phosphate Compound ◽  
Synthesis Strategy ◽  
Phosphorylation Reaction ◽  
Subsequent Calcination

AbstractWe report a synthesis strategy for pure hydroxyapatite (HAp) using an amorphous calcium carbonate (ACC) colloid as the starting source. Room-temperature phosphorylation and subsequent calcination produce pure HAp via intermediate amorphous calcium phosphate (ACP). The pre-calcined sample undergoes a competitive transformation from ACC to ACP and crystalline calcium carbonate. The water content, ACC concentration, Ca/P molar ratio, and pH during the phosphorylation reaction play crucial roles in the final phase of the crystalline phosphate compound. Pure HAp is formed after ACP is transformed from ACC at a low concentration (1 wt%) of ACC colloid (1.71 < Ca/P < 1.88), whereas Ca/P = 1.51 leads to pure β-tricalcium phosphate. The ACP phases are precursors for calcium phosphate compounds and may determine the final crystalline phase.

scholarly journals Highly Porous Amorphous Calcium Phosphate for Drug Delivery and Bio-Medical Applications

Nanomaterials ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 20 ◽  
Author(s):  
Rui Sun ◽  
Michelle Åhlén ◽  
Cheuk-Wai Tai ◽  
Éva G. Bajnóczi ◽  
Fenne de Kleijne ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Calcium Phosphate ◽  
Amorphous Calcium Phosphate ◽  
Large Angle ◽  
Drug Carriers ◽  
Amorphous Calcium Carbonate ◽  
Practical Applications ◽  
The Stability ◽  
Highly Porous

Amorphous calcium phosphate (ACP) has shown significant effects on the biomineralization and promising applications in bio-medicine. However, the limited stability and porosity of ACP material restrict its practical applications. A storage stable highly porous ACP with Brunauer–Emmett–Teller surface area of over 400 m2/g was synthesized by introducing phosphoric acid to a methanol suspension containing amorphous calcium carbonate nanoparticles. Electron microscopy revealed that the porous ACP was constructed with aggregated ACP nanoparticles with dimensions of several nanometers. Large angle X-ray scattering revealed a short-range atomic order of <20 Å in the ACP nanoparticles. The synthesized ACP demonstrated long-term stability and did not crystallize even after storage for over 14 months in air. The stability of the ACP in water and an α-MEM cell culture medium were also examined. The stability of ACP could be tuned by adjusting its chemical composition. The ACP synthesized in this work was cytocompatible and acted as drug carriers for the bisphosphonate drug alendronate (AL) in vitro. AL-loaded ACP released ~25% of the loaded AL in the first 22 days. These properties make ACP a promising candidate material for potential application in biomedical fields such as drug delivery and bone healing.

How similar are amorphous calcium carbonate and calcium phosphate? A comparative study of amorphous phase formation conditions

CrystEngComm ◽  
2018 ◽  
Vol 20 (1) ◽  
pp. 35-50 ◽  
Author(s):  
I. Buljan Meić ◽  
J. Kontrec ◽  
D. Domazet Jurašin ◽  
A. Selmani ◽  
B. Njegić Džakula ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Calcium Phosphate ◽  
Comparative Study ◽  
Amorphous Phase ◽  
Phase Formation ◽  
Amorphous Calcium Carbonate ◽  
Formation Conditions ◽  
Amorphous Phase Formation

Precipitation domains of ACP and ACP increase with the complexity of the system, the ACP one being always larger.

Ultrastructural, Elemental and Mineralogical Analysis of Vascular Calcification in Atherosclerosis

2017 ◽  
Vol 23 (5) ◽  
pp. 1030-1039 ◽  
Author(s):  
Ida Perrotta ◽  
Edoardo Perri
Keyword(s):  
Calcium Phosphate ◽  
Vascular Calcification ◽  
Amorphous Calcium Phosphate ◽  
Matrix Vesicles ◽  
Structural Features ◽  
Human Aorta ◽  
Apatite Formation ◽  
Cellular Mechanisms ◽  
Microscopy Imaging ◽  
Mineral Deposition

AbstractOver the past few decades, remarkable progress has been achieved in terms of understanding the molecular and cellular mechanisms of atherosclerotic vascular calcification and the important role of matrix vesicles in initiating and propagating pathologic tissue mineralization has been widely recognized. Despite these recent advances, however, no definitive data are currently available regarding the texture and composition of the minerals that grow in the vessel wall during the course of the disease. Using different electron microscopy imaging and analysis, we demonstrate that vascular cells can produce and secrete more than one type of matrix vesicles which act as sites for initial mineral deposition independently of their structural features. Our results reveal that apatite formation in the atherosclerotic lesions of the human aorta occur through the deposition of amorphous calcium phosphate that matures over time, transforms into crystalline hydroxyapatite, and radiates towards the lumen of the vesicles, finally forming the calcified spherules. Elemental and mineralogical analyses also demonstrate that the presence of mature and stable amorphous calcium phosphate deposits in the affected tissues is linked to the incorporation of magnesium, which probably delay the conversion to the crystalline phase. Though more rarely, the presence of calcium oxalate crystals has been also documented.

Synchrotron X-Ray Microanalysis and Imaging of Synthetic Biological Calcium Carbonate in Comparison With Archaeological Samples Originating from the Large Cave of Arcy-sur-Cure (28000-24500 BP, Yonne, France)

2013 ◽  
Vol 19 (6) ◽  
pp. 1523-1534 ◽  
Author(s):  
Emilie Chalmin ◽  
Ina Reiche
Keyword(s):  
Calcium Carbonate ◽  
Calcium Phosphate ◽  
Formation Process ◽  
Amorphous Calcium Phosphate ◽  
Analytical Methods ◽  
X Ray ◽  
Phosphate Phase ◽  
Carbonate Formations ◽  
Calcium Phosphate Phase ◽  
Case Based

AbstractBiosynthetic calcite samples were investigated using combined synchrotron X-ray microspectroscopy mapping. These samples were prepared with bacteria isolated from the Large cave of Arcy-sur-Cure in which prehistoric figures are masked by an opaque calcite layer. The biotic or abiotic origin of this layer is the issue of the present work. As previously known, a large community of bacteria may be involved in the CaCO3 formation in caves. A mixture of calcite/vaterite was obtained from bacteria isolated from the cave. Therefore, we can offer conclusions on their calcifying capability. The rare presence of vaterite in cave environments may be treated as a marker of biotic carbonate formations. Moreover, an amorphous calcium phosphate phase was present in the form of a calcite/vaterite mixture in the biotic model samples. This mixture of phases could be used as a tracer of the biotic process of CaCO3 formation. These biotic tracer phases were not identified using the applied analytical methods in the natural samples taken from the opaque calcite layers that covered the prehistoric figures of the Large cave. In this case, based on the obtained results, the biotic calcite formation process is likely to be considered as an undetectable effect at minimum.

scholarly journals Reversal of Root Caries with Casein Phosphopeptide-Amorphous Calcium Phosphate and Fluoride Varnish in Xerostomia

2021 ◽  
pp. 1-10
Author(s):  
Ahmed Sleibi ◽  
Anwar R. Tappuni ◽  
Aylin Baysan
Keyword(s):  
Calcium Phosphate ◽  
Amorphous Calcium Phosphate ◽  
Primary Root ◽  
Severity Index ◽  
Salivary Flow ◽  
Root Caries ◽  
Carious Lesions ◽  
Group 2 ◽  
Casein Phosphopeptide ◽  
Group 1

Different formulas of topical fluoride have been used to manage root carious lesions. This clinical trial aimed to investigate the efficacy of a dental varnish containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and fluoride compared with fluoride alone in reversing/arresting root caries in xerostomic patients over 1 year. A total of 80 patients (age range 45–92 years) with primary root caries (<i>n</i> = 184 root carious lesions) and unstimulated salivary flow rate of &#x3c;0.2 mL/min were randomly allocated to receive either dental varnish containing CPP-ACP and 5% fluoride (group 1: MI varnish; GC, Japan) (<i>n</i> = 41, 83 lesions), or dental varnish with 5% fluoride alone (group 2: NUPRO White; Dentsply, USA) (<i>n</i> = 39, 101 lesions). Clinical assessments with Severity Index (SI) for root caries, DIAGNOdent measurements, and varnish application were carried out at baseline, 3, 6, and 12 months. Standard oral hygiene instructions with 1,450 ppm fluoride toothpastes were provided for both groups. After 3 months, 63.9% (<i>n</i> = 46) of root caries in group 1 became hard (SI: 0) compared with 39.3% (<i>n</i> = 35) in group 2 (<i>p</i> &#x3c; 0.01). After 6 and 12 months, the differences in SI were insignificant (group 1, <i>n</i> = 60, 83.3%) (group 2, <i>n</i> = 66, 74.2%) (<i>p</i> = 0.36), and (group 1, <i>n</i> = 60, 89.6%) (group 2, <i>n</i> = 67, 81.7%, <i>n</i> = 1 soft, 1.2%) (<i>p</i> = 0.29), respectively. In both groups, noncavitated leathery lesions were more likely to become hard when compared to the cavitated root caries. A significant decrease in plaque index, surface roughness, lesion dimension, and DIAGNOdent readings with a significant increase in lesion distance from the gingival margin was reported in both groups (<i>p</i> &#x3c; 0.05). This study has provided evidence that fluoride dental varnish either with or without calcium and phosphate has the potential to arrest/reverse root caries, especially noncavitated lesions for patients with xerostomia.

Impacts of Initial Ca/P on Amorphous Calcium Phosphate

2021 ◽  
Author(s):  
Alexandria J. Hoeher ◽  
Sebastian T. Mergelsberg ◽  
Olaf J. Borkiewicz ◽  
F. Marc Michel
Keyword(s):  
Calcium Phosphate ◽  
Amorphous Calcium Phosphate
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