Calcium Sodium Phosphate Research Articles

Bioactivity behavior of Ag2O or CuO doped in glass systems of Na2O–CaF2–P2O5 and Na2O–CaO–P2O5 and their glass–ceramic derivatives assessed by FTIR, X-ray diffraction and SEM measurements

Glasses from the two systems (Na2O–CaF2–P2O5) and (Na2O–CaO–P2O5) doped with 0.2% CuO or Ag2O were prepared by melting annealing technique. Samples from the glasses were thermally heat treated to convert them to their glass–ceramic derivatives. FTIR spectra of the glasses and glass–ceramics were examined before and after immersion in SBF for 2 weeks at 37 °C to justify the spectral changes correlated with the bioactivity behavior of the tested samples. X-ray diffraction was utilized to identify the formed crystalline phases in the glass–ceramics upon thermal heat treatment. The crystalline phases are identified to be dependent on the chemical composition of the base glass and consisting of sodium phosphate and calcium phosphate crystalline phases beside combined sodium calcium fluoride phosphate crystalline phases and the sharing of the dopants. FTIR spectra after immersion indicate the appearance of two far-IR peaks which are characteristic for calcium phosphate or hydroxyapatite. SEM investigations confirm the bioactivity behavior through the appearance of the rounded or nodular-shaped crystalline phase. The optical and PL spectra indicate the complete transparency of the glasses in the visible except of interference of UV absorption band due to trace ferric ions impurities.

Evaluation of Fluidized Bed Ashes from Animal Wastes, Properties, Environmental Impact and Valorization

Use of secondary fuels for power production, such as animal and agricultural wastes, is becoming important nowadays, in view of the declining reserves of fossil fuels. Fluidized bed furnaces offer many advantages, such as fuel flexibility, high efficiency and low pollutant emissions. However, bottom or fly ashes produced from these appliances may create technical and environmental problems. In this study, agricultural wastes from the island of Crete (S. Europe) were co-fired in a fluid bed unit and bottom and fly ashes were characterized by mineralogical and chemical analyses. The effect of ash materials on system’s performance, as well as their environmental impact and valorization were assessed. The results showed that all ashes were enriched in Ca, Si, Mg, P, K. These elements were principally associated with calcite, anhydrite, quartz, dolomite, hydroxyapatite, fairchildite and arcanite minerals. Animal waste ashes contained whitlockite, calcium sodium phosphate and epsonite. Combustion of animal manure above 1000°C could lead to deposition problems in furnaces. Heavy metals Cu, Zn, Mn and Sr dominated in fly ashes. Toxic elements leached through alkaline soil of phyllitic and quarzitic nature were below legislation limits for land disposal. All ashes could be used for soil amelioration, liming or possibly fertilization.

The influence of Si4+ co-doping on the spectroscopic properties of β-NaCaPO4:Eu2+/Eu3+

A series of luminescent materials based on a sodium calcium phosphate matrix doped with europium and different concentrations of silicon ions was synthesized using the Pechini method.

Decomposition mechanism of a mixed rare earth concentrate with sodium hydroxide in the microwave heating process

In this paper, a novel process is proposed for extracting rare earth elements through intensifying the decomposition of mixed rare earth concentrates by microwave heating. The objective of the present study was to investigate the phase transition mechanism of a mixed rare earth concentrate with sodium hydroxide in a microwave field. To this end, the decomposition and separation efficiencies of the rare earth elements and fluorine were analyzed. The results showed that the decomposition reaction of the tested mixed rare earth concentrate in the microwave irradiation field occurred in three stages. The rare earth elements initially presented in bastnaesite and monazite were gradually converted to rare earth hydroxides (RE(OH)3), rare earth oxides (RE2O3), and composite oxides (Ce0.5Nd0.5O1.75), with fluorine eventually forming sodium fluoride. The decomposition ratio of the mixed concentrate and conversion ratio of the fluoride reached 88.73% and 89.32%, respectively. Furthermore, the decomposition temperature of the mixed concentrate with microwave heating was lower than that required with conventional heating, which indicated that microwave heating could decrease the thermodynamic reaction temperature. The results of the microscopic morphology analysis showed that after microwave heating, the samples exhibited two distinct particle morphologies, which was different from that of a mixed concentrate in any case. The decompositions of bastnaesite, monazite, and fluorite were somewhat non-interfering in nature, and sodium fluoride and calcium phosphate were separated from the rare earth oxides in the decomposition products. These results indicated that the proposed process was conducive to the separation of rare earth elements and fluoride and helpful for improving the efficiency of rare earth leaching.

Crystallization kinetics and heat treatment temperature on microstructure and properties of Na2O-CaO-P2O5 bioactive glass system

This study deals with the effects of heat treatment temperature on the thermal and mechanical properties of Na2O-CaO-P2O5 glasses and glass-ceramics. The major crystalline phase was calcium phosphate along with sodium calcium phosphate as the minor crystalline phases presented in the glass-ceramics. Vickers hardness, Knoop hardness and Young's modulus values of the glass-ceramics decrease with increasing of heat treatment temperature, however, the opposite trend is found for the fracture toughness values. H550 sample confirms the dendritic-like structure, H600 and H650 samples confirms the lamellar bone-like structures and H700 sample confirms the scaffold-like structure. The microstructure, with cluster of dendritic crystal and lamellar structure, indicates a typical two-dimensional crystallization mechanism, which agrees with the above analysis of Avrami exponent (n = 2.8) for glass sample at Tp1 while scaffold structure indicates a typical three-dimensional crystallization mechanism, which is in good agreement with the above analysis of Avrami exponent (n = 4.2) for glass sample at Tp2. Moreover, all Na2O-CaO-P2O5 bioactive glass-ceramics are not toxic to the living cell and have a good bioactive property.

Crystallization Kinetics and Heat Treatment Temperature on Microstructure of Na<sub>2</sub>O-CaO-P<sub>2</sub>O<sub>5</sub>-TiO<sub>2</sub> Glass System

Bioactive glass ceramics from Na2O-CaO-P2O5-TiO2 system have been fabricated by conventional melt quenching method. In order to change the fabricated glass to glass ceramic samples, a heat treatment technique was employed using temperatures ranging between 700 and 900°C for 2 h. Glass transition and crystallization temperature were analyzed via differential thermal analyzer (DTA). In addition, phase formation and microstructure of the glass-ceramics were also investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). From the crystallization kinetics, the crystallization rate constant (n) of the glass was found to be close to the value of 3, indicating the two-dimensional growth of crystals occurred in the glass ceramics. From the XRD results, the major crystalline phases were sodium titanium phosphate and calcium sodium phosphate along with titanium dioxide as the minor crystalline phases presented in high heat treatment temperatures (750-900°C) of the glass ceramics. SEM of the crystallized base glass Na2O-CaO-P2O5-TiO2 system, showed that crystallization of dendritic-like growths in the glass ceramics.

Element speciation in UK biomass power plant residues based on composition, mineralogy, microstructure and leaching

Biomass ash management is an escalating issue in many countries because of increasing numbers of biomass power plants. Comprehensive characterization of biomass ashes with emphasis on element speciation, and solubility of nutrients (e.g., K and P) and pollutants is essential for potential utilization of these residues for soil nutrition. All the UK biomass ashes investigated, whether from combustion of poultry litter, meat and bone meal, and straw, were alkaline and contained high concentrations of P, K, and Ca. The biomass air pollution control (APC) residues were enriched in K, Cl, S and Zn, and contained less lithophile elements, such as Al, Ca, P, Mg, Si, Ti, and Ba, compared to the bottom ashes. P appeared in: 1) bottom ashes as apatite and other phosphates (potassium hydrogen phosphate and potassium iron phosphate in the bottom ashes from combustion of poultry litter); 2) APC residues from combustion of poultry litter as potassium sodium calcium phosphate. K is present mainly in sylvite, arcanite, and some phosphates. Na, K, Cl, and S were easily leached by water from the biomass APC residues. However, water leaching of P, Ca, and Mg was very low, with leaching of P possibly controlled by hydroxyapatite. Aqueous Zn, Cu and Pb appear to prevail in the form of neutral and anionic hydroxide complexes, which are toxic and easily accessible chemical forms for live organisms. Application of the poultry litter bottom ashes as a PK fertiliser in agriculture is appropriate. However, direct application of APC residues to agricultural fields is not appropriate but recovery of K and P from that material should be considered.

Bioactivity and mineralization of natural hydroxyapatite from cuttlefish bone and Bioglass® co-sintered bioceramics.

In this study, bioactive hydroxyapatite (HAP)-based bioceramics starting from cuttlefish bone powders have been prepared and characterized. In particular, fragmented cuttlefish bone was co-sintered with 30 wt% of Bioglass® -45S5 to synthesize HAP-based powders with enhanced mechanical properties and bioactivity. Commercial synthetic HAP was treated following the same procedure and used as a reference. The structure and composition of the bioceramics formulations were characterized using Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy. After the thermal treatment of cuttlefish bone powder added with 30 wt% Bioglass, new phases with compositions of sodium calcium phosphate [Na3 Ca6 (PO4 )5 ], β-tricalcium phosphate [Ca3 (PO4 )] and amorphous silica were detected. In vitro cell culture studies were performed by evaluating proliferation, metabolic activity and differentiation of human osteoblast-like cells (MG63). Scaffolds made with cuttlefish bone powder exhibited increased apatite deposition, alkaline phosphatase activity and cell proliferation compared with commercial synthetic HAP. In addition, the ceramic compositions obtained after the combination with Bioglass® further enhanced the metabolic activity of MG63 cell and promoted the formation of a well-developed apatite layer after 7 days of incubation in Dulbecco's modified Eagle's medium.

Microstructures of alendronate sodium/calcium phosphate bone cement composites

Objective Observation contains of Alendronate sodium/calcium phosphate cement composite system of Alendronate Sodium on calcium phosphate cement curing process curing effects of micro-structure. Methods Preparation of different concentrations (0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 wt%) load drug Alendronate sodium calcium phosphate cement, using x-ray diffractometer, scanning electron microscope and observation of Archimedes’ methods of drainage of Alendronate Sodium load effects on the microstructure of calcium phosphate bone cement. Results Allan phosphine acid sodium of added on bone cement hydration product of real phase composition Shang not produced effect; scan electric mirror Xia several group samples micro structure basic similar, most Crystal mutual interwoven into mesh structure or fusion into Board-like structure, are is coral sample-like Crystal; pore rate experiment proved, with drug concentration of increased, composite system pore rate with of reduced, pore rate followed by for (52.5±0.6)%, (43.0±0.4)%, (47.2±0.7)%, (41.3±0.3)%, (36.7±0.5)%, (29.4±0.8)%, (33.6±0.3)%, statistically significant difference among the groups of samples (P=0.032), proving that drug load can make the matrix becomes more dense. Conclusion Alendronate Sodium loading has no effect on microstructure of calcium phosphate cement, calcium phosphate cement drug Alendronate Sodium is more stable complex vector. Key words: Alendronate Sodium; Calcium phosphate cement; Microstructure

3D printing of mineral-polymer bone substitutes based on sodium alginate and calcium phosphate.

We demonstrate a relatively simple route for three-dimensional (3D) printing of complex-shaped biocompatible structures based on sodium alginate and calcium phosphate (CP) for bone tissue engineering. The fabrication of 3D composite structures was performed through the synthesis of inorganic particles within a biopolymer macromolecular network during 3D printing process. The formation of a new CP phase was studied through X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. Both the phase composition and the diameter of the CP particles depend on the concentration of a liquid component (i.e., the “ink”). The 3D printed structures were fabricated and found to have large interconnected porous systems (mean diameter ≈800 μm) and were found to possess compressive strengths from 0.45 to 1.0 MPa. This new approach can be effectively applied for fabrication of biocompatible scaffolds for bone tissue engineering constructions.

Novel polyvinyl alcohol-bioglass 45S5 based composite nanofibrous membranes as bone scaffolds

Composite nanofibrous membranes based on sol-gel derived 45SiO2 24.5CaO 24.5 Na2O 6 P2O5 (bioglass, BG) and 43SiO2 24.5CaO 24.5 Na2O 6 P2O5 2Fe2O3 (magnetic bioglass, MBG) blended with polyvinyl alcohol (PVA) have been electrospun. These low cost membranes were mostly amorphous in structure with minor crystalline (sodium calcium phosphate) precipitates. All membranes were biodegradable. Among these, the composites exhibited higher tensile strength, better proliferation of human osteosarcoma MG63 cells and higher alkaline phosphatase enzyme activity than the bare PVA membrane, indicating their potential in bone tissue engineering. The magnetic PVA-MBG scaffold was also found to be a promising candidate for magnetic hyperthermia application.

Fabrication of 3D calcium phosphates based scaffolds using bacterial cellulose as template

Bacterial cellulose – calcium phosphates composite materials were synthesized by successive immersing of bacterial cellulose membranes prepared in our laboratory in precursor solutions under ultrasonic irradiation, which provides the necessary cations for the formation of calcium phosphate phases at the surface of bacterial cellulose fibers. The subsequent thermal treatment at 700 or 1000°C of the hybrid materials previously described allowed the obtaining of 3D porous scaffolds with different morphologies, as a function of the number of immersing cycles and calcining temperature. All samples exhibit similar phase composition, mainly based on hydroxyapatite and buchwaldite (sodium calcium phosphate). In the case of the composites thermally treated at lower temperature, the microstructure is fluffy and composed of large grains and monocrystalline nanorods, while the masses calcined at higher temperatures have a trabecular appearance, looking like a natural bone. The biological properties of the resulting architectures were also investigated.

Evolution of magnetic and bone mineral phases in heat‐treated bioactive glass containing zinc and iron oxides

Melt‐quenched 15(ZnO,Fe2O3) 50SiO2·20(CaO,P2O5) 15Na2O bioactive glass was heat treated at temperatures (TA) ranging from 550°C to 850°C for different time periods (tA=1, 2 and 3 hours) to understand its devitrification characteristics. Crystallization of calcium sodium phosphate, zinc ferrite, magnetite, and hematite phases depended on heat treatment conditions. Decrease in saturation magnetizations (Ms) with increase in tA of glass heat treated at TA≥750°C is attributed to the formation of hematite which is a weak magnetic material. Magnetic properties as functions of TA and tA are interpreted on the basis of clustering of Fe ions, super‐exchange interaction between Fe2+ and Fe3+ ions and formation of ferrimagnetic and weakly magnetic iron oxide phases with different heat treatment conditions. Electron paramagnetic resonance parameters reveal the variations in site distortions and randomness in Fe ion environment in the matrix upon heat treatment. In vitro mineralization ability of the glass‐ceramics was evaluated by immersion in simulated body fluid (SBF) and monitoring both the pH variation of SBF and formation of hydroxyapatite surface layer as a function of immersion time. These studies help in assessing these glass‐ceramics for hyperthermia treatment and in optimizing the processing conditions for this application.

Biocompatibility and Biodegradation of Multiphasic Calcium Phosphate Ceramic Bone Substitute Transformed by Ostrich Cancellous Bone for Bone Tissue Engineering

A kind of novel multiphasic calcium phosphate ceramic bone substitute transformed by ostrich cancellous bone (OCB) was explored in this article. In this study we investigated the characterization, biocompatibility, biodegradability and in vivo osteoconductive property of the material. Scanning electron microscope (SEM) and X-ray diffraction (XRD) were used to characterize the material. Biocompatibility and biodegradation were confirmed by testing the hemolysis and intramuscular implantation. Bone marrow stromal cells (BMSCs) were also used to perform biocompatibility. Besides, material/BMSCs composites were implanted into the subcutaneous of back of nude mice to evaluate the osteoconductive property of the material. SEM analysis showed that the presence of a large amount of micropores within macropore walls and the interporous connections were abundant which indicated that the material possessed enough surface area. XRD pattern showed the peaks were corresponding to the characteristic for hydroxyapatite (HA), β-tricalcium phosphate (β-TCP), and sodium calcium phosphate (NaCaPO4). Culturing of BMSCs on the scaffolds revealed the cells were able to attach and proliferate easily on the surface and the pores of the scaffolds. Moreover, this scaffolds had a good performance of biodegradation in vivo. Finally, histological observation of heterotopic bone formation revealed newly formed bone at 8 weeks after transplantation. The results of this study demonstrated that the multiphasic calcium phosphate ceramic had good biocompatibility and its surface configuration and pore structure were suitable for BMSCs to attach and proliferate and also had a good osteoconductive property, which suggested that the material could be used as a bone tissue engineering scaffold in the future.

Effect of Hydroxyapatite Reinforced with 45S5 Glass on Physical, Structural and Mechanical Properties

This paper presents a study of physical and structural properties of Hydroxyapatite (HA) reinforced with different compositions of 45S5 (SG) bioglasses at different sintering temperatures. Hydroxyapatite reinforced with different compositions of 45S5 bioglasses had been prepared and investigated in terms of density, mechanical strength, and crystalline phases. A decrease in the density of HA was observed after the incorporation of SG, owing to the trapping of air in the SG reinforced HA after sintering process. When compared to the pure HA, different crystalline phases, such as β-tricalcium phosphate, calcium phosphate silicate and sodium calcium phosphate, were detected when different compositions of SG were incorporated into the HA

Multi-methodological characterisation of calcium phosphate in late-Antique glass mosaic tesserae

The present study focuses on calcium phosphate identified in some late-Antique glass tesserae, green or blue in colour, from Padova (Italy) and Tyana (Turkey). It is generally accepted that calcium phosphate is a primary opacifier, probably obtained by deliberate addition of bone powder to a transparent glass. However, no specific crystallographic–chemical–spectroscopic studies have been performed on this important type of opacifier until now. Multi-methodological investigations on calcium phosphate, on its reaction rim, and on interactions with surrounding soda–lime–silica glass were carried out in this work by means of scanning electron microscopy (SEM), electron backscattered diffraction (EBSD), electron microprobe (EMPA), and micro-Raman spectroscopy, in order to clarify the nature of these inclusions and provide new insights into the production technologies of such kind of glass tesserae. Our results show that calcium phosphate grains are actually hydroxyapatite characterised by an evident reaction rim, which is enriched in sodium derived from the surrounding glass and replacing calcium of the opacifier. Such a cation replacement process between opacifier and glassy matrix is also confirmed by the presence of newly formed crystals composed of sodium calcium phosphate (β-rhenanite) and calcium silicate (wollastonite, polytype 1-T). β-Rhenanite and wollastonite are generally found in the proximity of calcium phosphate grains. Notwithstanding the geographical distance between Padova and Tyana (more than 2000km), comparable results were found in all the tesserae from both sites, suggesting similar and highly standardised production technologies of late-Antique tesserae with calcium phosphate as opacifier.

Microwave-assisted rapid preparation of Ca10Na(PO4)7 using sodium triphosphate as a phosphorus source

As a potential orthopedic biomaterial, calcium sodium phosphate (CNP) represents a viable alternative to the quintessentially important β-tricalcium phosphate (β-TCP). The conventional solid-state synthesis of CNP requires extensive time and energy with ease of introduction of impurities and formation of coarse particles needing further comminution. The present work demonstrates a simple but versatile microwave assisted method to prepare CNP with negative zeta potential using sodium polyphosphate and calcium chloride as precursors. There are several important characteristics of the product. The as-synthesized CNP crystals showed two different morphologies- polygonal and whisker-like. The as-formed CNP was thermally stable without new phase nucleation after calcination at 1000°C. This material promoted the proliferation of osteoblast cells as compared to HA in vitro. Additionally, the particles can be easily dispersed because of their negative zeta potential. Finally, the particles revealed their anti-Escherichia coli attachment potential. With all of these attributes, it is expected CNP can be a potential biomaterial in orthopedics and a good candidate for fabrication of composites with relevant biopolymer matrices.

In Vitro Evaluation of the Composite Alginate - Calcium Phosphate Materials for Prototyping Technologies in Bone Defects Substitution

Porous granular composite biomaterials based on sodium alginate and calcium phosphate component: 1% sodium alginate; sodium alginate with gelatin (80/20); calcium phosphate ceramics (CHA, TCP and OCP) and composite materials alginate/CHA, alginate/TCP, alginate/OCP, alginate/gelatin (80/20)/TCP and alginate/TCP/CHA/OCP were investigated for cytotoxicity and matrix (for cells) properties in dynamics of cultivation (up to 21 days). Two adhesive cell lines - immortalized human fibroblasts (HF, strain 1608 hTERT) and human osteosarcoma (MG-63) were used for in vitro MTT assay. OCP material showed its cytotoxicity while all its composites possessed weak matrix properties. For further research on the development of prototyping technologies 3 samples of composite materials were selected: alginate/CHA, alginate/TCP and alginate/gelatin (80/20)/TCP that are characterized by cytocompatibity and the presence of either expressed or moderate matrix properties of the surface for cells.

In Vitro Evaluation of the Composite Alginate - Calcium Phosphate Materials for Prototyping Technologies in Bone Defects Substitution

Porous granular composite biomaterials based on sodium alginate and calcium phosphate component: 1% sodium alginate; sodium alginate with gelatin (80/20); calcium phosphate ceramics (CHA, TCP and OCP) and composite materials alginate/CHA, alginate/TCP, alginate/OCP, alginate/gelatin (80/20)/TCP and alginate/TCP/CHA/OCP were investigated for cytotoxicity and matrix (for cells) properties in dynamics of cultivation (up to 21 days). Two adhesive cell lines - immortalized human fibroblasts (HF, strain 1608 hTERT) and human osteosarcoma (MG-63) were used for in vitro MTT assay. OCP material showed its cytotoxicity while all its composites possessed weak matrix properties. For further research on the development of prototyping technologies 3 samples of composite materials were selected: alginate/CHA, alginate/TCP and alginate/gelatin (80/20)/TCP that are characterized by cytocompatibity and the presence of either expressed or moderate matrix properties of the surface for cells.

An elucidating study on physical and structural properties of 45S5 glass at different sintering temperatures

This paper presents a study of physical and structural properties of 45S5 bioactive glass (BG) at different sintering temperatures. The 45S5 BG, one of the most important formulations, was composed of 45% SiO2, 24.5% Na2CO3, 24.5% CaCO3 and 6% P2O5. The aim of this research was to gain a better understanding on the effect of heat treatment towards phase transformation of the 45S5 BG. Each composition of the 45S5 BG was sintered at three different temperatures, which were 800°C, 1000°C and 1200°C. The formation of crystallization or phase changes before and after the heat treatment was being identified using X-ray diffraction analysis. Bonding of the BG before and after sintering was being investigated using Fourier transform infrared spectroscopy while morphology of the 45S5 BG was determined by field emission scanning electron microscopy (FESEM). The X-ray pattern indicated the presence of silicate and phosphate in the glass system. Amorphous glassy phases with sodium calcium silicate (Na2Ca3Si6O16) and sodium calcium phosphate (NaCaPO4) were observed in the sintered glass. A decrement in density was due to formation of additional porosity which occurred due to decomposition of oxide materials in the glass. This was confirmed by FESEM results, which proved an increase in the porosity at high temperature.