scholarly journals Phase Transformation of Octacalcium Phosphate in vivo and in vitro

1992 ◽  
Vol 11 (2) ◽  
pp. 130-140,217 ◽  
Author(s):  
Seiji BAN ◽  
Toshikage JINDE ◽  
Jiro HASEGAWA
Keyword(s):  
Phase Transformation ◽  
Octacalcium Phosphate

scholarly journals Cemp1-p3 Peptide Promotes the Transformation of Octacalcium Phosphate into Hydroxyapatite Crystals

Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1131
Author(s):  
Maricela Santana ◽  
Gonzalo Montoya ◽  
Raúl Herrera ◽  
Lía Hoz ◽  
Enrique Romo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Octacalcium Phosphate ◽  
Sequence Motifs ◽  
Simple Method ◽  
Transmission Electron ◽  
Precursor Phase ◽  
Mineralized Tissues ◽  
Potent Growth

Dental cementum contains unique molecules that regulate the mineralization process in vitro and in vivo, such as cementum protein 1 (CEMP1). This protein possesses amino acid sequence motifs like the human recombinant CEMP1 with biological activity. This novel cementum protein 1-derived peptide (CEMP1-p3, from the CEMP1’s N-terminal domain: (QPLPKGCAAVKAEVGIPAPH), consists of 20 amino acids. Hydroxyapatite (HA) crystals could be obtained through the combination of the amorphous precursor phase and macromolecules such as proteins and peptides. We used a simple method to synthesize peptide/hydroxyapatite nanocomposites using OCP and CEMP1-p3. The characterization of the crystals through scanning electron microscopy (SEM), powder X-ray diffraction (XRD), high--resolution transmission electron microscopy (HRTEM), and Raman spectroscopy revealed that CEMP1-p3 transformed OCP into hydroxyapatite (HA) under constant ionic strength and in a buffered solution. CEMP1-p3 binds and highly adsorbs to OCP and is a potent growth stimulator of OCP crystals. CEMP1-p3 fosters the transformation of OCP into HA crystals with crystalline planes (300) and (004) that correspond to the cell of hexagonal HA. Octacalcium phosphate crystals treated with CEMP1-p3 grown in simulated physiological buffer acquired hexagonal arrangement corresponding to HA. These findings provide new insights into the potential application of CEMP1-p3 on possible biomimetic approaches to generate materials for the repair and regeneration of mineralized tissues, or restorative materials in the orthopedic field.

In vitro and in vivo biocompatibility and corrosion behaviour of a bioabsorbable magnesium alloy coated with octacalcium phosphate and hydroxyapatite

2015 ◽  
Vol 11 ◽  
pp. 520-530 ◽  
Author(s):  
Sachiko Hiromoto ◽  
Motoki Inoue ◽  
Tetsushi Taguchi ◽  
Misao Yamane ◽  
Naofumi Ohtsu
Keyword(s):  
Magnesium Alloy ◽  
Corrosion Behaviour ◽  
Octacalcium Phosphate

A Comparative Study of Bioceramics In Vitro and In Vivo

2005 ◽  
Vol 284-286 ◽  
pp. 11-14 ◽  
Author(s):  
Yang Leng ◽  
Ren Long Xin ◽  
Ji Yong Chen
Keyword(s):  
Calcium Phosphates ◽  
Glass Ceramics ◽  
Octacalcium Phosphate ◽  
Rabbit Muscle ◽  
In Vivo Experiments ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
Dental Applications

Bioactive calcium phosphate (Ca-P) formation in bioceramics surfaces in simulated body fluid (SBF) and in rabbit muscle sites was investigated. The examined bioceamics included most commonly used bioglass®, A-W glass-ceramics and calcium phosphates in orthopedic and dental applications. The Ca-P cyrstal structures were examined with single crystal diffraction patterns in transmission electron microscopy, which reduced possibility of misidentifying Ca-P phases. The experimental results show that capability of Ca-P formation considerably varied among bioceramics, particularly in vivo. Octacalcium phosphate (OCP) was revealed on the all types of bioceramics in vitro and in vivo experiments. This work leads us to rethink how to evaluate bioactivity of bioceramics and other orthopedic materials which exhibit capability of osteoconduction by forming direct bonding with bone.

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.

Amelogenin Nanospheres Modulate Crystal Habit of Octacalcium Phosphate and Hydroxyapatite Crystals in In Vitro Model Systems

2000 ◽  
Vol 620 ◽  
Author(s):  
Moradian-Oldak J. ◽  
Wen H.B. ◽  
Fincham A.G. ◽  
Iijima M.
Keyword(s):  
Membrane System ◽  
Octacalcium Phosphate ◽  
Model Systems ◽  
Crystal Habit ◽  
Width Ratio ◽  
Growth Morphology ◽  
Oriented Growth ◽  
Apatite Crystals

ABSTRACTThis paper is a short review of recent studies, which were undertaken to investigate interactions of amelogenin with octacalcium phosphate (OCP), and apatite. OCP crystals were grown using two independent experimental systems; (a) in a 10% gelatin gel, containing 0-2% amelogenin, where the crystals were formed in a double-diffusion chamber, and (b) in a 10% pure amelogenin gel, where crystal growth took place in between a cation-selective and a dialysis membrane. Apatite crystals were grown from a supersaturated calcifying solution on a bioactive glass in the absence (SCSB) and the presence of amelogenin (SCSrM179). It was found that OCP crystals formed in 10% gelatin gel containing 1-2% amelogenin were longer (3-5 times larger in aspect ratio) than the OCP crystals formed in 10% gelatin without amelogenin. A profound effect was that found in the cation selective membrane system when 10% amelogenin inhibited the growth morphology in a specific manner. Affected crystals had a length to width ratio twice larger than that of control crystals while the width to thickness ratio was about 1/12 of that of the control crystals. Amelogenin promoted the formation of bundles of lengthwise apatite crystals, which were all oriented parallel to their c axes when grown on SCSrM179. It was found that individual apatite crystals within those bundles adopted an elongated, curved shape. The data presented here suggest that amelogenin nanospheres modulate the growth morphology of apatite and OCP crystals and indicate significant functional roles for amelogenin proteins during the in vivo oriented growth of enamel crystallites.

Effect of Octacalcium Phosphate Ionic Dissolution Products on Osteoblastic Cell Differentiation

2007 ◽  
Vol 361-363 ◽  
pp. 31-34 ◽  
Author(s):  
Takahisa Anada ◽  
Akihiro Araseki ◽  
Shou Matsukawa ◽  
Tomokazu Yamasaki ◽  
Shinji Kamakura ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
Conditioned Medium ◽  
Molecular Mechanisms ◽  
Octacalcium Phosphate ◽  
Osteoblastic Cell ◽  
Mouse Bone Marrow ◽  
Phosphate Ions ◽  
Proliferation And Differentiation

Our previous studies suggested that synthetic octacalcium phosphate (OCP) enhances bone regeneration more than hydroxyapatite (HA). However, the molecular mechanisms to induce osteogenic phenotype in osteoblast by OCP have not been identified. OCP tended to convert into an apatite structure in vivo and in vitro, and its process was accompanied by calcium consumption from the surrounding solution and the release of phosphate ions into the solution at a physiological condition. The present study was designed to investigate whether the dissolution of ionic products of OCP affects on proliferation and differentiation of mouse bone marrow stromal ST-2 cells in vitro. The number of cells treated with OCP-conditioned medium was slightly decreased in comparison to that of control at day 7. On the other hand, the level of alkaline phosphatase activity increased in OCP-conditioned medium. These results demonstrated that OCP is capable of inducing osteoblastic cell differentiation in ST-2 cells.

Octacalcium Phosphate as a Precursor in Biomineral Formation

1987 ◽  
Vol 1 (2) ◽  
pp. 306-313 ◽  
Author(s):  
W.E. Brown ◽  
N. Eidelman ◽  
B. Tomazic
Keyword(s):  
Thermogravimetric Analysis ◽  
Calcium Phosphates ◽  
Three Dimensional ◽  
Octacalcium Phosphate ◽  
Basic Form ◽  
Vacancy Defects ◽  
Impurity Ions

What are biominerals and how are they formed? It is usually assumed: (i) that the prototype for most apatitic biominerals is hydroxyapatite (OHAp), Ca5(PO4) 3OH; and (ii) that the OHAp structure has been modified by the presence of impurity ions and vacancy defects in specific OHAp lattice sites. The usual answer, at least implicitly, to the second question is that the apatitic mineral is formed directly by the precipitation of ions from the surrounding solution. Our answers are: (i) that apatitic biominerals are formed through a precursor mechanism in which octacalcium phosphate (OCP), Ca8H 2(PO4)6·5H2O, precipitates first and then hydrolyzes ireversibly in situ to a transition product intermediate to OCP and OHAp; and (ii) that this product, "octacalcium phosphate hydrolyzate" (OCPH), may contain (a) OHAp-like and OCP-like domains in varying amounts, (b) vacancy defects and impurity ions in lattice sites in these domains, and (c) various kinds of one-, two-, and three-dimensional defects which are not present in either the OHAp or the OCP lattice, these defects being formed during the in situ hydrolysis step. A calcification model of this type was first proposed in 1957, but full acceptance was delayed because most of the evidence was circumstantial and in vitro in nature. The situation has changed radically because of three unrelated studies that are in vivo in nature but lead to the same conclusion: I. 32P-pyrolysis studies of rat enamel: The results clearly demonstrated that an acidic calcium phosphate precursor was involved. II. Precipitation of calcium phosphates in serum. Ultrafiltered serum was equilibrated with brushite. Subsequent changes in the ionic concentrations revealed that OCP was formed at first and then hydrolyzed to a more basic form, OCPH, but never reached the solubility of OHAp. III. Physicochemical properties of cardiovascular biominerals: We recently characterized biominerals in cardiovascular deposits in an encompassing variety of ways. As an overall conclusion, OCPH was the prototype most compatible with the data [including indices of refraction, solubility, P2O74- formation on pyrolysis, thermogravimetric analysis (TGA) measurements, presence of water, and incorporation of CO32-, Na+, and Mg2+]. This calcification model has important consequences relative to all kinds of calcification and decalcification processes, including those of enamel.

The Role of Brushite and Octacalcium Phosphate in Apatite Formation

1992 ◽  
Vol 3 (1) ◽  
pp. 61-82 ◽  
Author(s):  
Mats S.-A. Johnsson ◽  
George H. Nancollas
Keyword(s):  
Calcium Phosphate ◽  
Octacalcium Phosphate ◽  
In Vivo Studies ◽  
Apatite Formation ◽  
Acidic Solutions ◽  
Phosphate Phase ◽  
Apatite Mineral

Studies of apatite mineral formation are complicated by the possibility of forming several calcium phosphate phases. The least soluble, hydroxyapatite (HAP), is preferentially formed under neutral or basic conditions. In more acidic solutions phases such as dicalcium phosphate dihydrate (Brushite, DCPD) and octacalcium phosphate (OCP) are often found. Even under ideal HAP precipitation conditions the precipitates are generally nonstoichiometric, suggesting the formation of calcium-deficient apatites. Both DCPD and OCP havea been implicated as possible precursors to the formation of apatite. This may occur by the initial precipitation of DCPD and/or OCP followed by transformation to a more apatitic phase. Although DCPD and OCP are often detected during in vitro crystallization, in vivo studies of bone formation rarely show the presence of these acidic calcium phosphate phases. In the latter case the situation is more complicated, since a large number of ions and molecules are present that can be incorporated into the crystal lattice or adsorbed at the crystallite surfaces. In biological apatite, DCPD and OCP are usually detected only during pathological calcification where the pH is often relatively low. In normal in vivo calcifications these phases have not been found, suggesting the involvement of other precursors or the formation of an initial amorphous calcium phosphate phase (ACP) followed by transformation to apatite.

Kinetics of the Phase Transformation of Non-HIPed Zirconia Femoral Heads

2007 ◽  
Vol 330-332 ◽  
pp. 1203-1206 ◽  
Author(s):  
Junji Ikeda ◽  
Giuseppe Pezzotti ◽  
Mikio Iwamoto ◽  
Masaru Ueno
Keyword(s):  
Phase Transformation ◽  
Spectroscopic Observation ◽  
X Ray ◽  
Hip Simulator ◽  
Raman Microprobe ◽  
Femoral Heads ◽  
Kinetics Of ◽  
Simulator Test

The kinetics of tetragonal-to-monoclinic phase transformation (t→m transformation) in the earlier generation zirconia femoral heads was evaluated by X-ray diffractometry, laser microscopy and Raman microprobe spectroscopy. From previous results of hip-simulator study, it was confirmed that phase transformation on the surface of zirconia femoral heads had little influence on wear rate of UHMWPE sockets, and in some zirconia femoral heads, only a slight increase in monoclinic fraction was observed during hip-simulator test. In this study, we suggest that the models of phase transformation progress during tests in hip-simulator and aging tests are different based on both laser microscopic and Raman/fluorescence spectroscopic observation. Besides this finding, this study shows that Raman spectroscopy is a useful technique for the evaluation of the kinetics of phase transformation in femoral heads after both in vitro and in vivo environmental exposure.

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