β-TCP Powder Research Articles

Influence of the Ca/P ratio and cooling rate on the allotropic α↔β-tricalcium phosphate phase transformations

Alpha-tricalcium phosphate (α-TCP) is a component of particular interest in the formulation of apatitic calcium phosphate based bone cements. During the setting reaction of this type of cements, a calcium deficient hydroxyapatite with composition similar to bone hydroxyapatite is formed. But the purity levels of the commercially available products based on α-TCP are generally low, and their prices are prohibitive. Such stringent conditions are pushing most of the researchers in the area of bone cements towards preparing α-TCP in their own laboratories. The low degree of purity of α-TCP based products is generally due to an incomplete β-TCP → α-TCP phase transformation and/or to a partial α-TCP → β-TCP reversal during cooling. Despite extensive research efforts, contradictory reports exist about the effects of composition of the starting material, cooling rates and the importance of quenching for maintaining α-TCP purity. The present work aims at shedding further light on this issue by controlling the relevant parameters of wet synthesis of the starting β-TCP powders and their heat treatment schedule in order to transform them in high purity α-TCP products. The key experimental variables investigated included the composition of the starting β-TCP powders, namely the Ca/P ratio, the maximum heat treatment temperatures, and the cooling rates.

Polylactic Acid/Nanostructured Si-Substituted β-Tricalcium Phosphate Composites for Biodegradable Fixation Medical Devices.

Organic/inorganic biocomposite materials for biodegradable fixation medical devices require osteoconductivity, biocompatibility, and adequate mechanical properties with biodegradation behavior. The objective of this study was to investigate the effect of Si ions substituted in β-tricalcium phosphate (β-TCP) on the mechanical properties of organic/inorganic biocomposites. Biodegradable composite materials were prepared with polylactic acid (PLA) as the matrix and nano Si-substituted β-TCP as the osteoconductive filler by solvent mixing and conventional molding. The nanostructured Si-substituted β-TCP powders were synthesized by co-precipitation, controlling the quantity of Si ions. The amount of nanostructured Si-substituted β-TCP powders in composites was varied in the 0-40 wt% range and the material properties were compared with those of pure β-TCP/PLA composites. The influence of Si ions on the mechanical properties of the composites was evaluated by tensile and flexural tests.

3D Powder Printed Bioglass and β-Tricalcium Phosphate Bone Scaffolds.

The use of both bioglass (BG) and β tricalcium phosphate (β-TCP) for bone replacement applications has been studied extensively due to the materials’ high biocompatibility and ability to resorb when implanted in the body. 3D printing has been explored as a fast and versatile technique for the fabrication of porous bone scaffolds. This project investigates the effects of using different combinations of a composite BG and β-TCP powder for 3D printing of porous bone scaffolds. Porous 3D powder printed bone scaffolds of BG, β-TCP, 50/50 BG/β-TCP and 70/30 BG/β-TCP compositions were subject to a variety of characterization and biocompatibility tests. The porosity characteristics, surface roughness, mechanical strength, viability for cell proliferation, material cytotoxicity and in vitro bioactivity were assessed. The results show that the scaffolds can support osteoblast-like MG-63 cells growth both on the surface of and within the scaffold material and do not show alarming cytotoxicity; the porosity and surface characteristics of the scaffolds are appropriate. Of the two tested composite materials, the 70/30 BG/β-TCP scaffold proved to be superior in terms of biocompatibility and mechanical strength. The mechanical strength of the scaffolds makes them unsuitable for load bearing applications. However, they can be useful for other applications such as bone fillers.

Sinus Tract Formation with Chronic Inflammatory Cystic Mass after Beta Tricalcium Phosphate Insertion.

Beta tricalcium phosphate (β-TCP) is one of allogenic bone substitute which is known to have interconnected pores that draws cell and nutrients for bone generation. It has been resulted in good outcomes for bone defect coverage or augmentation. However, several studies have also reported negative outcomes and associated complications including unexpected formation of cystic mass, continuous pain and secretion. We present the case of a 36-year-old man with a right cheek cystic mass who had a history of right zygomaticomaxillary (ZM) complex fracture and surgical correction with β-TCP powder insertion to ZM bone defect. Excisional biopsy under local anesthesia revealed calcified mass in a sinus tract which was found to be connected to the ZM bone defect site in postoperative computed tomography image. Further excision under general anesthesia was performed to remove the sinus tract and fine granules which filled the original defect site. Pathologic report revealed bony spicules and calcification materials with chronic foreign body reaction. Postoperative complications and recurrence were not reported.

Fe-doped brushite bone cements with antibacterial property

In present research, Fe-doped brushite bone cements were synthesized. The setting time, microstructure and antibacterial property of samples were investigated. The results showed that the setting time of cements was retarded to about 20 min and 123 min, respectively, as iron doping content increasing from 1 mol% to 5 mol% in β-TCP powder. Moreover, Fe-doped cements had much bigger crystal particles and calcium iron phosphate was identified in them. Furthermore, Fe-doped cements performed well in inhibiting the growth of Staphylococcus aureus and Pseudomonas aeruginosa, and larger inhibition halo was obtained with more iron content. Nevertheless, the Fe-loaded cements were not so sensitive to Escherichia coli as to the other two bacteria.

Effects of barium zirconium titanate on the properties of β-tricalcium phosphate bioceramics

In the present work, a new composite between β-tricalcium phosphate (a bioceramic material) and barium zirconium titanate (a ferroelectric material) were fabricated. Beta-tricalcium phosphate (β-TCP) powder was synthesized from egg shells while barium zirconium titanate powder was synthesized from metal oxide powders. The composites were fabricated by a solid-state reaction method. Effects of barium zirconium titanate on many properties of the composites were investigated. Barium zirconium titanate additive improves the electrical properties of the composites such as dielectric, ferroelectric and piezoelectric properties. Furthermore, the mechanical properties, such as hardness are improved by the additive. In-vitro bioactivity test suggests that β-tricalcium phosphate has a higher apatite forming ability as compared to the BZT. The obtained results indicate that the composites are a promising biomaterial candidate.

Preparation and Characterization of β-Tricalcium Phosphate Powders with High Solubility for Chelate-Setting Calcium-Phosphate Cements

We have previously developed a novel chelate-setting β-tricalcium phosphate (β-TCP) cement with non-fragmentation property in vivo. This novel cement has been set on the basis of chelate-setting mechanism of inositol phosphate (IP6). In this study, β-TCP powders were synthesized by mechanochemical method, and the as-prepared powders were heated at 600-1300°C for 1 h. Some properties of the resulting powders were examined. The crystalline phase of the resulting powders in the range of 600-1100°C was of β-TCP single phase. In the cases at 1200°C and 1300°C, the resulting powders were composed of β-TCP and α-TCP. Median particle sizes of the resulting powders increased with heating temperature from 5.35 μm up to 47.7 μm. Dissolution rate of Ca2+ ions from the β-TCP powders was measured by Japanese Industrial Standard T 0330-3. When the heating temperature was at 700°C, the Ca2+ ions solubility was highest among examined ones. The β-TCP powder heated at 700°C for 1 h will be expected as the starting powder for paste-like artificial bone filler with excellent bioresorbability.

On the synthesis and characterization of β-tricalcium phosphate scaffolds coated with collagen or poly (D, L-lactic acid) for alveolar bone augmentation.

Objectives:After tooth loss, dimensional alterations on the alveolar bone ridge can occur that can negatively affect the placement of dental implants. The purpose of this study was to evaluate the synthesis, and mechanical properties of β-tricalcium phosphate (β-TCP) scaffolds coated with bioabsorbable polymers, namely, collagen and poly (D, L-lactic acid) (PDLLA).Materials and Methods:β-TCP powder was obtained by reactive milling and then characterized by X-ray diffraction and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). β-TCP scaffolds were obtained by replica method, in which polyurethane foams are immersed in β-TCP suspension and thereafter submitted to a thermal treatment to remove the polyurethane and sinter the ceramic. Type-I collagen or PDLLA were used to coat the β-TCP scaffolds by dip-coating method. Scaffolds were separated in four groups depending on the coating material: noncoated (Group A), double immersion in collagen (Group B), double immersion in PDLLA (Group C), and ten immersions in PDLLA (Group D). Samples were characterized by compressive tests and SEM/EDS. Data were statistically analyzed through two-way ANOVA (p = 0.05).Results:Chemical and microscopic analyses revealed proper morphology and chemical composition of powder particles and scaffolds with or without polymeric coatings. Scaffolds coated with PDLLA showed higher compressive strength (0.11 ± 0.054 MPa) than those of collagen (0.022 ± 0.012 MPa) or noncoated groups (0.024 ± 0.012 MPa).Conclusions:The coating method of β-TCP with PDLLA revealed a potential strategy to increase the mechanical strength of porous ceramic materials while collagen can enhance cell migration.

Development of a bioactive porous collagen/β-tricalcium phosphate bone graft assisting rapid vascularization for bone tissue engineering applications.

We developed collagen (COL) and collagen/beta tricalcium phosphate (COL/β-TCP) scaffolds with a β-TCP/collagen weight ratio of 4 by freeze-drying. Mouse bone marrow-derived mesenchymal stem cells (BMMSCs) were cultured on these scaffolds for 14 days. Samples were characterized by physicochemical analyses and their biological properties such as cell viability and alkaline phosphatase (ALP) activity was, also, examined. Additionally, the vascularization potential of the prepared scaffolds was tested subcutaneously in Wistar rats. We observed a microporous structure with large porosity (∼95-98%) and appropriate pore size (120-200 µm). The COL/β-TCP scaffolds had a much higher compressive modulus (970 ± 1.20 KPa) than pure COL (0.8 ± 1.82 KPa). In vitro model of apatite formation was established by immersing the composite scaffold in simulated body fluid for 7 days. An ALP assay revealed that porous COL/β-TCP can effectively activate the differentiation of BMMSCs into osteoblasts. The composite scaffolds also promoted vascularization with good integration with the surrounding tissue. Thus, introduction of β-TCP powder into the porous collagen matrix effectively improved the mechanical and biological properties of the collagen scaffolds, making them potential bone substitutes for enhanced bone regeneration in orthopedic and dental applications. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 73-85, 2018.

Injectable thermosensitive alginate/β-tricalcium phosphate/aspirin hydrogels for bone augmentation.

In this study, an injectable and thermo-sensitive alginate/β-tricalcium phosphate hydrogel (TSAH/β-TCP) was prepared for aspirin release to a bone defect. Aspirin was dissolved into a mixture of poly(N-isopropylacrylamide) (PNIPAAm), an aminated alginate-g-PNIPAAm co-polymer, and β-TCP powders. Scanning electron microscopy showed that TSAH/β-TCP had an interconnected porous microstructure with a porosity of 86.78%. The cross-linked hydrogel released approximately 40% of the aspirin in the first 3 days and then slowly released the remainder. At a low concentration (≤100 μg/mL), aspirin did not promote cell proliferation, but enhanced the alkaline phosphatase activity, and osteocalcin (OCN) and collagen I expression of human bone marrow-derived mesenchymal stem cells. The TSAH/β-TCP/aspirin hydrogel was injected into the periosteum of the rat cranial bone, and its in vivo bone-forming ability was evaluated at 12 weeks. A bone morphogenetic protein 2 (BMP-2)-loaded TSAH/β-TCP hydrogel was injected as a control. Micro-computed tomography showed that the percentage of mineralized tissue in the TSAH/β-TCP/BMP-2 and TSAH/β-TCP/aspirin groups were similar and significantly higher than that in the TSAH/β-TCP group. Immunohistochemical staining showed considerable expression of OCN, especially in the TSAH/β-TCP/BMP-2 and TSAH/β-TCP/aspirin groups. These results suggest that the injectable TSAH/β-TCP/aspirin hydrogel has great potential for bone regeneration. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1739-1751, 2018.

Effect of Calcination Temperatures on Phase Transformation and Stability of β-Tricalcium Phosphate Powder Synthesized by a Wet Precipitation Method

Beta-tricalcium phosphate (β-TCP) was never synthesized directly using an aqueous method. As-precipitated powder from a wet chemical method needs to undergo a heat-treatment process (or calcination) to enable the intermediate phase (s) to be transformed into single-phase TCP. In this work, calcium hydroxide, (Ca (OH)2), and phosphoric acid, (H3PO4), were mixed as the precursor materials with a Ca/P ratio of 1.5,. The mixture was stirred at a fixed stirring speed of 200 rpm and a stirring duration of 2 hours. The precipitate thus obtained was filtered and dried overnight before being tested by differential scanning calorimetry and thermogravimetry (DSC/TG) up to 1300°C for thermal behaviour upon firing. The powders were then calcined at various temperatures (500°C, 700°C, 900°C 1000°C, 1100°C, 1200°C and 1300°C) for a duration of 2 hours. The calcined powders obtained were analysed by x-ray diffraction (XRD) to determine the transformation of phases. Monetite and hydroxyapatite were the phases detected after calcination at 500°C and 700°C, whilst at a temperature of 900°C up to 1300°C, only a single phase β-TCP was observed. Microstructural observation by scanning electron microscopy (SEM) was conducted on the β-TCP powders obtained at calcination temperatures of 900°C to 1300°C. The results showed a massive crystal growth of the aggregated particles, but even so, the phase remained stable as monolithic β-TCP.

MBG-Modified β-TCP Scaffold Promotes Mesenchymal Stem Cells Adhesion and Osteogenic Differentiation via a FAK/MAPK Signaling Pathway.

The β-TCP scaffold has been widely used as a bone graft substitute, but the traditional PMMA molding method-induced undesirable mechanical strength and poor interconnectivity still have not been addressed until now. In this study, a MBG-based PU foam templating method was developed to fabricate β-TCP scaffolds with desirable microtopography. The MBG gel, as both binder and modifier, prepared by a modified sol-gel method with controlled viscosity is incorporated with β-TCP powder and thereafter is impregnated into PU foam. The resultant hybrid scaffolds exhibited interconnected macropores (200-500 μm) and distinctive micropores (0.2-1.5 μm), especially for the TCP/25MBG (with 25 wt % content MBG). As expected, the compression strength of β-TCP/MBG composite scaffolds was enhanced with increasing MBG content, and TCP/50MBG (with 50 wt % content MBG) exhibited almost 100-fold enhancement compared to the pure β-TCP. Intriguingly, the cell affinity and osteogenic capacity of rBMSCs were also dramatically improved the best on TCP/25MBG. Further investigation found that the subtle, grainy-like microtopography, not the chemical composition, of the TCP/25MBG favored the adsorption of Fn and expression of integrin α5β1 and further facilitated FA formation and the expression of p-FAK, following activation of the MAPK/ERK signaling pathway and ultimately upregulated expression of osteogenic genes. Further in vivo experiments confirmed the promoted osteogenesis of TCP/25MBG in vivo. The results suggest that such a novel MBG-based PU foam templating method offers new guidance to construct hierarchically porous scaffolds, and the prepared MBG-modified β-TCP scaffold will have great potential for future use in bone tissue regeneration.

A novel wet polymeric precipitation synthesis method for monophasic β-TCP

β-Tricalcium phosphate (β-Ca3(PO4)2, β-TCP) powders were synthesized using wet polymeric precipitation method for the first time to our best knowledge. The results of X-ray diffraction analysis showed the formation of almost single a Ca-deficient hydroxyapatite (CDHA) phase of a poor crystallinity already at room temperature. With continuously increasing the calcination temperature up to 800°C the crystalline β-TCP was obtained as the main phase. It was demonstrated that infrared spectroscopy is very effective method to characterize the formation of β-Ca3(PO4)2. The SEM results showed that β-Ca3(PO4)2 solids were homogeneous having a small particle size distribution. The β-TCP powders consisted of spherical particles varying in size from 100 to 300nm. Fabricated β-TCP specimens were placed to the bones of the rats and maintained for 1–2months. The histological properties of these samples will be also investigated.

Cytotoxicity and in vivo biosafety of the polylactide based bone composite materials

In this study, we investigated the in vitro cytotoxicity and in vivo biosafety of reinforced polylactide (PLA) composites with hyaluronic acid-chitosan (HACS) complex and β-tricalcium phosphate (β-TCP) powder. The cytotoxicity of HACS/PLA (with β-TCP) composites was almost the same as that of neat PLA indicating that HACS/PLA (with β-TCP) composites did not have toxic effects. In in vivo biosafety tests using X-ray and micro-CT imaging, HACS/PLA (with β-TCP) composites did not show any fracture during 20 weeks of implantation in the tibia and femur of rabbits. The HACS/PLA (with β-TCP) composites did not induce severe inflammatory responses such as recruitment of macrophages around the implantation site, as assessed by H&E and immune staining of biopsy samples, for 6 weeks after insertion into SD rats. Addition of β-TCP powder to HACS/PLA composite enhanced bone induction and regeneration. The HACS/PLA composites prepared in the present study have potential maxillofacial and orthopedic applications.

A Simple Microwave Route for the Synthesis of Tricalcium Phosphate (β-TCP) Powders for Bone Healing Applications

The recent trend in bioceramics research is mainly concentrated on bioactive ceramics, i.e. hydroxyapatite, tricalcium phosphates and bioactive glasses, as they exhibit superior biological properties over other materials. Among these tricalcium phosphates have been found very important member due to their biocompatible and biodegradable properties that can help to promote new bone formation when implanted in a bone defect site. Therefore the aimed of the present work was to investigate the synthesis of tricalcium phosphate via simple microwave route at Ca/P molar ratios below, 1.67 and at pH of reaction environment equal 5. The detail characterizations of the prepared samples were carried out using Energy-dispersive X-ray spectroscopy (EDX), FT-IR spectroscopy (FTIR) and X-Ray Diffraction (XRD) analysis. From the analysis of EDX, FTIR and XRD patterns, the formation of β-TCP was confirmed.

Injectable MnSr-doped brushite bone cements with improved biological performance.

Good mechanical properties and high injectability are the major requirements to ensure widespread application of calcium phosphate cements (CPCs) as bone substitutes in minimally invasive surgeries. However, obtaining CPCs that exhibit a good compromise between these two properties as well as good biological performance is still a great challenge. This study presents novel solutions to improve these properties, which include (i) co-doping β-tricalcium phosphate (β-TCP) powder with Sr and Mn, and (ii) adding small amounts of saccharides (sucrose or fructose) to the setting-liquid solution. The combination of these two strategies enabled full injectability and significantly increased the wet compressive strength of CPCs in comparison to undoped or solely Sr-doped CPCs. Furthermore, the proliferative response of human MG63 osteoblastic cells, their rate of collagen-I secretion, and particularly their growth behaviour on the cement surfaces were also enhanced. The overall improved relevant properties of Mn/Sr co-doped CPCs with added sucrose, including in vitro biological performance, renders them very promising materials for bone regeneration and tissue engineering.

Effects of powder-to-liquid ratio on properties of β-tricalcium-phosphate cements modified using high-energy ball-milling.

The authors have developed a β-tricalcium-phosphate (β-TCP) powder modified mechano-chemically through the application of a ball-milling process (mβ-TCP). The resulting powder can be used in a calcium-phosphate-cement (CPC). In this study, the effects of the powder-to-liquid ratio (P/L ratio) on the properties of the CPCs were investigated, and an appropriate P/L ratio that would simultaneously improve injectability and strength was clarified. The mβ-TCP cement mixed at a P/L ratio of 2.5 and set in air exhibited sufficient injectability until 20 min after mixing, and strength similar to or higher than that mixed at a P/L ratio of 2.0 and 2.78. Although the mβ-TCP cements set in vivo and in SBF were found to exhibit a lower strength than those set in air, it did have an appropriate setting time and strength for clinical applications. In conclusion, P/L ratio optimization successfully improved the strength of injectable mβ-TCP cement.

Effect of βTricalcium Phosphate Nanoparticles Additions on the Properties of Gelatin-Chitosan Scaffolds

Bone tissue engineering, using a synthetic porous scaffold material provides some distinct advantages over autografting and allografting, and it is a rapidly growing alternative approach to heal damaged bone tissue. The current study focuses on fabrication and characterization of nano β-TCP incorporated gelatin- chitosan based composite scaffold for bone regeneration at the sites of musculoskeletal defects and disorders. Gelatin-chitosan scaffold reinforced with beta-tricalcium phosphate (β-TCP) nanopowder was fabricated through freeze drying of material’s suspension. From powder X-ray diffraction and Fourier transform infrared spectrometer analysis the presence of phase pure β-TCP powders in gelatin-chitosan matrix was confirmed. Gelatin-Chitosan-β- TCP (GCT) scaffold exhibited a homogenouos porous structure with an average pore size of 118 ± 11 μm. Micro-CT image confirmed interconnected porous network with homogeneous distribution of β-TCP nanoparticles in Gelatin- Chitosan (GC) matrix. GCT scaffold showed higher compressive strength of 2.45 ± 0.15 MPa as compared to 1 MPa exhibited by neat GC scaffold. Protein adsorption capacity was increased to 22 mg/cc in GCT scaffold from 13 mg/ cc in GC scaffold. Weight loss of GCT scaffold was lower of 26% as compared to 47% in GC scaffold after 8 weeks of incubation in phosphate buffer solution of pH 7.4. Mesenchymal stem cells cultured onto GCT scaffold exhibited higher degree of lamellipodia and filopodia extensions and greater spreading onto GCT scaffold as compared to that in GC scaffold after 7 and 14 days of culture. MTT assay suggested higher degree of proliferation of MSCs cultured onto GCT scaffold as compared to that onto pure GC scaffolds. This study demonstrates that β-TCP incorporation into gelatin- chitosan matrix improved osteogenic potential of the scaffold suitable for bone tissue engineering

Improved forming performance of β-TCP powders by doping silica for 3D ceramic printing

High-quality β-Ca3(PO4)2 (TCP) powders with the improved forming performance were prepared by doping silica in solid state method for 3D ceramic printing. The different concentrations of silica were employed as the sintering additive to investigate the effect on the dispersity of β-TCP powders, microstructures and the densities of as-prepared ceramics. The sintering additive could reduce the agglomeration of raw powders in the progress of ball-milling, and weakly agglomerated powders were obtained which meant improvement of formability. Meanwhile, the average grain sizes decreased and densities of as-prepared β-TCP ceramics increased with the increasing of silica doping concentration. The sample with the best performance was achieved with 1.0 wt% SiO2 when sintered at 1050 °C for 8 h in air. Its average grain size and relative density were 0.57 μm and 70.42%, respectively.

Developing a multifunctional bio-ceramics composite based on β-tricalcium phosphate working as a single carrier for calcium supplement and low-dose drugs

AbstractThe aim of this work is to develop a multifunctional composite based on β-tricalcium phosphate (β-TCP) working as a single carrier that has a therapeutic function, as a calcium supplement, together with the capability for carrying low-dose drugs. The composite was prepared by blending synthetic β-TCP powder, sodium silicate, and citric acid. The synthetic β-TCP and its composite were characterized using X-ray powder diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy techniques. Mechanical testing and in-vitro drug release testing, using atenolol, of the fabricated tablets was conducted. The results revealed the synthesis of pure β-TCP powder and fabrication of optimal dense β-TCP-based composite. The β-TCP-based composite exhibited an optimal release behavior of atenolol together with releasing of synthetic β-TCP particles, a calcium supplement.