The porous scaffolds for bone tissue engineering were prepared by foam impregnation. The magnesium and aluminum acid phosphates were used as bonder and the hydroxyapatite ((Ca10 (PO4)6(OH)2, HA) powder as raw materials. Scanning electron microscopy (SEM) examination indicated that the 3D interconnected porous structure of the organic foam was replicated well by the scaffolds calcined at high temperature and the structural requirement of tissue engineering was satisfied. XRD analysis showed that the scaffold was composed of HA and Ca7Mg2P6O24 while calcined at 1150 degrees C for shorter time and of (Ca, Mg)3(PO4)2 when the time prolonged to 2 h. There was no peak of CaO found in the scaffolds by XRD. According to the culture in vitro, the scaffold possesses good biocompatibility and certain degree of degradability.
Aluminum Compounds ; chemistry ; Biocompatible Materials ; Bone Substitutes ; chemistry ; Calcium Phosphates ; chemistry ; Durapatite ; chemistry ; Phosphates ; chemistry ; Porosity ; Tissue Engineering

Calcium phosphate cement (CPC) is considered as an important bone repairing materials due to its excellent biocompatibility, osteoconductivity and remodellability, the study about its performance is still a hot topic in the field of bone tissue engineering. Premixed calcium phosphate cements (PCPC) has advantages that can save operatiion time,be convenient to the operation and preservation compared with the traditional way of immediately mixing calcium phosphate cement. PCCP has overcome the shortcomings of uneven and inadequate mixing, and can be arbitrarily remodeled according to the shape of defect, thus researches on PCCP has also become more and more interested
Bone Cements ; chemistry ; Calcium Phosphates ; chemistry ; Humans ; Materials Testing ; Solubility

In this paper, alpha-tricalcium phosphate (alpha-TCP) and tetracalcium phosphate (TTCP) respectively were chosen as basic compositions of phosphate bone cements. Other auxiliary materials such as hydroxyapatite (HAP), dicalcium phosphate dihydrate (DCPD), calcium carbonate (CaCO3), calcium oxide (CaO) and amorphous calcium silicate (CaSiO3) were added in the cements. Six kinds of composite bone cements were decided with 1.50 as their Ca/P ratio. Then the primary properties of them were studied. Ringer's simulated body fluid (SBF) tests were carried out for the samples. The changes of pH value in SBF and the compressive strength of the samples with the immersion time were studied. The results showed: the mixing liquid 0.25 M K2HPO4/KH2PO4 and amorphous CaSiO3 were effective for accelerating the setting of the cements; the initial setting time (It) was about 4-5.5 min and the final setting time (Ft) was about 18-19. 5 min. Amorphous calcium silicate can increase the compressive strength of the bone cements remarkably; the compressive strength of the alpha-TCP bone cement with the addition of suitable amount amorphous CaSiO3 reached 45.3 MPa after immersion in SBF for 14 days.
Bone Cements ; chemical synthesis ; chemistry ; Calcium Compounds ; chemistry ; Calcium Phosphates ; chemistry ; Compressive Strength ; Humans ; Silicates ; chemistry

In order to improve the mechanical properties of alpha-tricalcium phosphate (alpha-TCP), we prepared surface-modified carbon fibers (CF) reinforced alpha-TCP composite bone cement. Bone cement was soaked in Ringer's body solution to test its capacity of fast formation of hydroxyapatite crystals and self-solidification. Scan electronic microscope (SEM) observation and compressive strength measurement were taken to analyze the mechanical properties and the micro- morphological structure of CF reinforced alpha-TCP bone cement. The results showed that the bone cement was transferred into hydroxyapatite plates after being soaked in Ringer's simulated body fluid for 5 days. Suitable amount of carbon fibers could well spread in and bond with the matrix of the bone cement. The mechanical properties of the bone cement have been improved by CF reinforcing; the compressive strength reaches 46.7 MPa when the amount of carbon fibers is 0.5% in weight percent, which is 22% higher than that of the non-reinforced alpha-TCP bone cement.
Bone Cements ; chemistry ; Calcium Phosphates ; chemistry ; Carbon ; chemistry ; Durapatite ; chemistry ; Materials Testing

Microcrystalline cellulose (MCC), calcium phosphate (DCP)/MCC (4:1, w/w) and lactose (Lac)/MCC (4:1) pellets with different intragranular porosity were prepared in an extrusion-spheronizator and three volume ratios of ethanol/water were used as binder agents to prepare pellets. The compression behaviors of these pellets with different intragranular pore volume were evaluated with the parameters of Kawakita model. The results showed that high pore volume of pellets made up of MCC had the best compressibility and low pore volume of pellets had a poor compactibility. However, the compressibility of different porosity of pellets made up of DCP/MCC (4:1) or Lac/MCC (4:1) was good, but they were not significantly different. The reason might be the main compression mechanism of high porosity of MCC pellets was plastic deformation and that of DCP/MCC pellets or Lac/MCC pellets was not plastic deformation but fragmentation. These results can be observed directly by the SEM photographs. According to these results, the conclusion could be drawn that high porosity MCC pellets and different porosity DCP/MCC pellets and Lac/MCC pellets can be used as cushion granules to maintain the original shape and release characteristics of drug pellets when pellets were tabletted.
Calcium Phosphates ; chemistry ; Cellulose ; chemistry ; Drug Compounding ; methods ; Excipients ; Lactose ; chemistry ; Microspheres ; Porosity ; Pressure ; Tablets

All samples were divided into three groups and subjected to three different surface treatments, i.e. untreated group, group etched with mixed acid of 1:1 HCl and H2SO4 followed by immersion in 6N NaOH solution at 60 degrees C for 24 h and group etched with mixed acid of 1:1 HCl and H2SO4 followed by immersion in 6N NaOH solution at 60 degrees C for 24 h then heated at 600 degrees C for 1 h. After soaked in simulated body fluid for two weeks, a thin calcium phosphate coatings was precipitated on the surfaces of the two treated samples. Results of SEM and EDX showed that calcium phosphate coatings on the surfaces of the titanium samples etched and heated were more even than the titanium samples etched without heating. The analysis of XRD demonstrated the main component of calcium phosphate coating was hydroxyapatite.
Body Fluids ; chemistry ; Calcium Phosphates ; chemistry ; Coated Materials, Biocompatible ; chemistry ; In Vitro Techniques ; Materials Testing ; Titanium

Bone tissue engineering is a novel, developing and challenging science which provides a new way to repair bone lost from injury and disease. Porous calcium polyphosphate bioceramic is one kind of absorptable bioceramic. Owing to its fine biocompatibility and degradability, more and more pieces of research wark have been carried out in bone tissue engineering, and because of its special characteristics, calcium polyphosphate bioceramic is regarded as a promising material for solving the problem of how to match the degradation velocity of scaffold with the velocity of cell growth. The recent research of using calcium polyphosphate bioceramic as the scaffold in bone tissue engineering is summarized, including the property, synthesis and advances.
Bone Substitutes ; chemistry ; Bone and Bones ; Calcium Phosphates ; chemistry ; Humans ; Porosity ; Tissue Engineering ; Tissue Scaffolds ; chemistry

Porous calcium polyphosphate (CPP) has shown promise of tissue engineered implant application because of the biocompatibility and biodegradation. CPP with different polymerization degree were prepared by controlling the calcining time, and its polymerization degree could be calculated by developed method in this paper. Different crystal types CPP were prepared by quenching from the melt and crystallization of amorphous CPP. From the in vitro degradation, carried out in Tris-HCl buffer, the degradation velocity of CPP was controllable. The weight loss of CPP with different polymerization degrees and crystal types were different. With the increasing of polymerization degree, the weight loss during the degradation was decreasing, contrarily the strength of CPP was increasing. The amorphous CPP could degrade completely in 17 days while gamma-CPP do completely in 25 days. The degradation velocity beta-CPP and alpha-CPP was slower than gamma-CPP and the weight loss was about 12% and 5% respectively. The results of this study indicate that CPP have potential applications for bone tissue engineering as inorganic polymeric biomaterials.
Absorbable Implants ; Biocompatible Materials ; chemistry ; Bone Substitutes ; chemistry ; Calcium Phosphates ; chemistry ; Humans ; Tissue Engineering

Bone cement samples were made of tetracalcium phosphate (TTCP) and monocalcium phosphate monohydrate(MCPM) powder (Ca/P = 1.67) by using water and 5.24 mg/ml of self-made type I collagen sol as hardening liquid with the solid-liquid ratio of 3:1, their setting time and compressive strength were tested. The results showed that: the compressive strength of TTCP/MCPM bone cement containing collagen could increase from 17.8 +/- 1.9 MPa to 22.7 +/- 1.6 MPa, but its setting time hasn't been significantly affected; the compressive strength of both samples immersed in simulated body fluid (SBF) could increase, and the growth rate of the sample containing collagen increased especially; both samples immersed in SBF for 4d and 14d, whose compressive strength could increase to 31.8 +/- 3.9 MPa (collagen)/19.5 +/- 1.3 MPa and 38.1 +/- 3.1 MPa (collagen)/21.9 +/- 2.2 MPa. According to the IR analysis before and after the collagen was mineralized, it showed that: after the collagen was mineralized, the characteristic peaks of the collagen's amide I band showed red-shift, while the amide II band and the amide III band nearly disappeared, suggesting that chemical action occurred between the collagen and hydroxyapatite (HA), which should be the basis of the enhancement on the TTCP/MCPM bone cement caused by collagen; while according to the SEM and XRD patterns of the sample surface before and after the samples were immersed in SBF, it showed that: the immersion in SBF changed brushite (DCPD) into HA, at the same time, large number of new HA deposited, making the samples' surface more dense and smooth. It was not only the enhancement mechanism of immersion in SBF, but also showed the coagulating and hardening process of TTCP/MCPM bone cement was that: the DCPD was generated firstly, then it changed into HA.
Bone Cements ; chemistry ; Calcium Phosphates ; chemistry ; Collagen Type I ; chemistry ; Compressive Strength

Tooth decay is prevalent, and secondary caries causes restoration failures, both of which are related to demineralization. There is an urgent need to develop new therapeutic materials with remineralization functions. This article represents the first review on the cutting edge research of poly(amido amine) (PAMAM) in combination with nanoparticles of amorphous calcium phosphate (NACP). PAMAM was excellent nucleation template, and could absorb calcium (Ca) and phosphate (P) ions via its functional groups to activate remineralization. NACP composite and adhesive showed acid-neutralization and Ca and P ion release capabilities. PAMAM+NACP together showed synergistic effects and produced triple benefits: excellent nucleation templates, superior acid-neutralization, and ions release. Therefore, the PAMAM+NACP strategy possessed much greater remineralization capacity than using PAMAM or NACP alone. PAMAM+NACP achieved dentin remineralization even in an acidic solution without any initial Ca and P ions. Besides, the long-term remineralization capability of PAMAM+NACP was established. After prolonged fluid challenge, the immersed PAMAM with the recharged NACP still induced effective dentin mineral regeneration. Furthermore, the hardness of pre-demineralized dentin was increased back to that of healthy dentin, indicating a complete remineralization. Therefore, the novel PAMAM+NACP approach is promising to provide long-term therapeutic effects including tooth remineralization, hardness increase, and caries-inhibition capabilities.
Amines ; pharmacology ; Calcium ; Calcium Phosphates ; chemistry ; pharmacology ; Dentin ; chemistry ; Humans ; Nanocomposites ; chemistry ; Nanoparticles ; Tooth Remineralization ; methods