Production and Characterisation of a Collagen-Calcium Phosphate Composite for Use as a Bone Substitute

1998 ◽  
Vol 550 ◽  
Author(s):  
A.C. Lawson ◽  
J.T. Czernuszka
Keyword(s):  
Calcium Phosphate ◽  
Bone Substitute ◽  
Collagen Matrix ◽  
Octacalcium Phosphate ◽  
Entire Cross Section ◽  
Phosphate Ions ◽  
Precipitation Ph ◽  
Composite Microstructure ◽  
Composite Stiffness ◽  
Calcium Phosphate Precipitation

AbstractA composite for use as a bone substitute has been produced by the precipitation of calcium phosphate onto a collagen matrix. A collagen sheet is used as a membrane separating reservoirs of calcium and phosphate ions. The ions diffuse through the membrane and calcium phosphate precipitation occurs on and within the collagen matrix.Composites containing octacalcium phosphate or hydroxyapatite have been produced by varying the precipitation pH. If the correct balance of phosphate and calcium ion concentrations is achieved, precipitation occurs through the entire cross-section of the collagen sheet, giving a composite microstructure analogous to bone. The composite stiffness increases with increasing mineral content, reaching 2.8 GPa with 39 wt % mineral, when measured dry.

Synthesis of calcium phosphate crystals in a silica hydrogel containing phosphate ions

2009 ◽  
Vol 24 (6) ◽  
pp. 2154-2160 ◽  
Author(s):  
Taishi Yokoi ◽  
Masakazu Kawashita ◽  
Giichiro Kawachi ◽  
Koichi Kikuta ◽  
Chikara Ohtsuki
Keyword(s):  
Calcium Phosphate ◽  
Phosphoric Acid ◽  
Reaction Temperature ◽  
Crystal Morphology ◽  
Octacalcium Phosphate ◽  
Rate Determining Step ◽  
Phosphate Ions ◽  
Silica Hydrogels ◽  
Crystal Growth Mechanism ◽  
Different Types

Calcium phosphate crystals were synthesized by diffusing calcium ions into silica hydrogels containing phosphate ions. Hydroxyapatite [HAp, Ca10(PO4)6(OH)2] and octacalcium phosphate [OCP, Ca8(HPO4)2(PO4)4.5H2O] with different types of crystal morphology were formed in the gel. The HAp had an irregular or rod shape, a few micrometers in length, while the OCP had an irregular, spherulite, rod- or ribbonlike shape, ranging in size from a few micrometers to several tens of micrometers, depending on the amount of phosphoric acid added and the reaction temperature. The morphology of the OCP changed from an irregular shape to a ribbonlike or rod shape, via a spherulite shape, depending on the amount of phosphoric acid added and the reaction temperature. The degree of supersaturation of the reaction environment and the rate-determining step in the HAp and OCP crystal growth mechanism have been ascribed to the changes in crystal morphology of the HAp and OCP.

Effects of citrate and NaCl on size, morphology, crystallinity and microstructure of calcium phosphates obtained from aqueous solutions at acidic or near-neutral pH

2012 ◽  
Vol 79 (2) ◽  
pp. 238-248 ◽  
Author(s):  
Omar Mekmene ◽  
Thierry Rouillon ◽  
Sophie Quillard ◽  
Paul Pilet ◽  
Jean-Michel Bouler ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Calcium Phosphates ◽  
Octacalcium Phosphate ◽  
Inhibitory Effect ◽  
Particle Sizes ◽  
X Ray Diffraction ◽  
Phosphate Dihydrate ◽  
Constant Ph ◽  
Starting Solutions ◽  
Calcium Phosphate Precipitation

Precipitation of calcium phosphates occurs in dairy products and depending on pH and ionic environment, several salts with different crystallinity can form. The present study aimed to investigate the effects of NaCl and citrate on the characteristics of precipitates obtained from model solutions of calcium phosphate at pH 6·70 maintained constant or left to drift. The ion speciation calculations showed that all the starting solutions were supersaturated with respect to dicalcium phosphate dihydrate (DCPD), octacalcium phosphate (OCP) and hydroxyapatite (HAP) in the order HAP>OCP>DCPD. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) analyses of the precipitates showed that DCPD was formed at drifting pH (acidic final pH) whereas poor crystallised calcium deficient apatite was mainly formed at constant pH (6·70). Laser light scattering measurements and electron microscopy observations showed that citrate had a pronounced inhibitory effect on the crystallisation of calcium phosphates both at drifting and constant pH. This resulted in the decrease of the particle sizes and the modification of the morphology and the microstructure of the precipitates. The inhibitory effect of citrate mainly acted by the adsorption of the citrate molecules onto the surfaces of newly formed nuclei of calcium phosphate, thereby changing the morphology of the growing particles. These findings are relevant for the understanding of calcium phosphate precipitation from dairy byproducts that contain large amounts of NaCl and citrate.

Differences of Bone Regeneration by Various Calcium Phosphate/Collagen Composites

2007 ◽  
Vol 361-363 ◽  
pp. 1229-1232 ◽  
Author(s):  
Shinji Kamakura ◽  
Kazuo Sasaki ◽  
Yoshitomo Honda ◽  
Taisuke Masuda ◽  
Takahisa Anada ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Bone Regeneration ◽  
Cross Sections ◽  
Bone Substitute ◽  
Octacalcium Phosphate ◽  
Radiographic Examination ◽  
Synthetic Bone ◽  
Synthetic Bone Substitute ◽  
The Difference ◽  
Made In

Our previous studies showed that synthetic octacalcium phosphate (OCP) enhances bone regeneration more than hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP). Also, a synthetic bone substitute constructed of synthetic octacalcium phosphate (OCP) and porcine atelocollagen sponge (OCP/Col) showed stable bone regeneration. The present study was designed to investigate the difference of bone regeneration by OCP/Col and other calcium phosphate-collagen composites. OCP/Col, β-TCP$-collagen% composite (β-TCP/Col), or HA$-collagen% composite (HA/Col) sponge was prepared from pepsin-digested atelocollagen isolated from the porcine dermis and OCP, β-TCP, or HA granules, respectively. A standardized critical-sized defect was made in the rat calvarium, and various calcium phosphate-collagen composites were implanted into the defect. The rats were fixed at four weeks after implantation and radiographic and histological examinations were performed by undecalcified cross sections of implants. Radiographic examination showed that uniform radiopaque masses were observed in the created defects treated with OCP/Col, whereas granulous and foggy radiopacity was observed in β-TCP/Col and HA/Col. Histological examination showed that newly formed bone was observed in the reticulum of OCP/Col and around the implanted OCP. The regenerated bone by β-TCP/Col or HA/Col seemed to be less than that by OCP/Col and would not to be nucleated by the granules of β-TCP or HA. The present study indicated that bone regeneration by OCP/Col was different from those of β-TCP/Col and HA/Col. Application of OCP/Col would be expected for clinical use in the future.

Control of Calcium Phosphate Precipitation in Hydrogel

2007 ◽  
Vol 330-332 ◽  
pp. 79-82 ◽  
Author(s):  
Masanobu Kamitakahara ◽  
Shinichi Ogata ◽  
Masao Tanihara ◽  
Chikara Ohtsuki
Keyword(s):  
Calcium Phosphate ◽  
Calcium Phosphates ◽  
Agarose Gel ◽  
White Area ◽  
Negative Side ◽  
Positive Side ◽  
Phosphate Ions ◽  
Calcium Phosphate Precipitation ◽  
Controlled Precipitation ◽  
Cacl2 Solution

Electrophoresis can transport ions more rapidly and directionally in a gel. The controlled precipitation of calcium phosphates in an agarose gel was attempted by electrophoresis of calcium and phosphate ions. Wells were prepared on an agarose gel. A CaCl2 solution was placed in wells on the positive side and a Na2HPO4 solution in wells on the negative side. A potential of 100 V was then applied. White precipitates appeared in the gel after 11 min. The white area initially became larger and more intense with increasing time. However, after longer periods, the white area decreased and became weaker, before disappearing after 45 min. Spinous precipitates with a diameter of about 500 nm were obtained when the gels were collected after 20 min. The precipitates were characterized as particles of calcium phosphate.

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.

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.

scholarly journals Transfection of Capsaspora owczarzaki  using calcium-phosphate precipitation v1 (protocols.io.p4adqse)

protocols.io ◽  
2018 ◽  
Author(s):  
Helena Parra ◽  
N ria ◽  
Alberto Perez ◽  
Aleksandra Kozyczkowska ◽  
Sebasti n
Keyword(s):  
Calcium Phosphate ◽  
Calcium Phosphate Precipitation
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