Synthesis Of β-TCP Research Articles

Synthesis and Characterization of Mesoporous β-Tricalcium Phosphate

Reconstruction of bone defect due to a disease or a trauma can use autograft, allograft, xenograft or synthetic bonegraft as the bone substitute material. However, in particular cases, it is required a material that has a specific resorption characteristic, beside owning excellent bioactive properties, such as β-tricalcium phosphate (β-TCP). In this study, we report the synthesis of β-TCP particles with mesopores structure by using chitosan and aloe vera as templates. A solution of (NH4)2HPO4 was added dropwise into solution of Ca(NO3)2·4H2O and the template at 85°C for 2 hours, and subsequently aged for 3 hours. Then, the formed precipitate was washed and centrifuged repeatedly prior to drying at 80°C for 24 hours. Finally, the dried precipitate was calcined at 900°C for 1 hour to obtain β-TCP powder. Phase identification and mesopores structure were analyzed using X-ray diffraction (XRD), while the existence of functional groups was identified by Fourier-transform infrared (FTIR) spectroscopy. Microstructure and particle size distribution were characterized by scanning electron microscopy (SEM) and particle size analyzer (PSA), respectively. XRD analysis shows that β-TCP is dominant with the presence of small amount of impurities. Furthermore, low angle peak in XRD analysis indicates the formation of mesopores structure. From the SEM and PSA analysis, the morphology of both TCP-K and TCP-KA particles showed more large agglomerates and more heterogeneous particle size distribution due to the addition of the biopolymers in the synthesis of β-TCP.

Synthesis of β-TCP by sol-gel method: variation of Ca/P molar ratio

Beta-TCP has been synthesized by sol-gel method in ethanol media with Ca/P molar ratio of 1.0–1.5. Phosphorous pentoxide solution was slowly added into calcium nitrate tetrahydrate solution with gentle stirring to produce white gel. The white gel was dried at 80°C for 20 hours and continued by calcination process at 800°C for 30 minutes. The results showed that pure β-TCP powders was obtained from Ca/P molar ratio of 1.3. For Ca/P of 1.0-1.2, beside β-TCP, a little amount of β-CPP were found and for Ca/P ratio of 1.4-1.5, hydroxyapatite was formed as secondary product. The crystallite size of β-TCP was in a range of 32.96-47.82 nm. Morphology changed due to Ca/P molar ratio in which the size of irregular shape β-TCP became bigger as Ca/P molar ratio increased from 1.0 to 1.3. The presence of hydroxyapatite in the product has not changed the morphology shape but reduced its grain size.

Effect of Mn doping on the low-temperature synthesis of tricalcium phosphate (TCP) polymorphs

Effect of Mn doping on the low-temperature synthesis of tricalcium phosphate (TCP) polymorphs was demonstrated in α- and β-TCP polymorphs prepared by wet precipitation method under identical conditions and annealed at 700 °C. Calcium phosphates with Mn doping level in the range from 1 to 5 mol% were studied and the formation of desired polymorph was controlled by varying Mn content in as-prepared precipitates. It was found that increasing Mn content resulted in the formation of β-TCP, while α-TCP was obtained with low Mn doping level, whereas a mixture of two polymorphs was obtained for intermediate Mn concentrations. Moreover, doping with Mn ions allowed the synthesis of β-TCP at relatively low temperature (700 °C). Synthesized compounds were characterized by X-ray diffraction (XRD) analysis, electron paramagnetic resonance (EPR), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), inductively coupled plasma optical emission spectrometry (ICP-OES) and colorimetric MTT assay.

Synthesis of β-TCP and CPP containing biphasic calcium phosphates by a robust technique

Biphasic calcium phosphate (BCP) compositions consisting of β-tricalcium phosphate (β-TCP) and calcium pyrophosphate (CPP) are potential biodegradable ceramics for bone regeneration. The present work demonstrates the formation of such dense ceramics by first preparing the precursors of nano-sized, amorphous, and equiaxed calcium pyrophosphate particles, and then sintering the precursors at 900°C to transform them into desired BCP. However, if the complex of calcium tripolyphosphate was used, only CPP could be generated. It was also observed that the incorporation of Mg2+ had several effects on the resulting products including: (1) promoting the generation of meso-porous precipitates; (2) favoring the formation of β-TCP instead of CPP; (3) reducing the grain size and increasing the density of the sintered ceramics, and (4) enhancing the negative electric charge of the BCP surface. Thus, the as-prepared BCP ceramics can serve as potential bone substitute materials in orthopedic applications.