Biphasic Calcium Phosphate Bioceramics Research Articles

Influences of curing depth and layer thickness on forming accuracy and mechanical properties of biphasic calcium phosphate bioceramics fabricated by vat photopolymerization

Vat photopolymerization (VPP) is a high potential and efficient method for fabricating advanced ceramics. However, the selection of printing strategy importantly determines the geometrical accuracy and mechanical strength of ceramic parts prepared by VPP. In this study, the effects of the curing depth (Cd) to layer thickness (Lt) ratio and Lt on forming accuracy, microstructures, mechanical properties, surface roughness of biphasic calcium phosphate (BCP) bioceramic green bodies and sintered bodies were investigated. When the Cd/Lt ratio was smaller than 4.0, and the Lt was not over 50 μm, the green bodies presented high forming accuracy (the dimension errors ˂ 3.50 %). Inappropriate Cd/Lt and Lt caused lots of defects including different types of cracks and delamination on green bodies and sintered bodies, and impaired their mechanical strength. The optimal Cd/Lt ratio and Lt were obtained to be 4.0 and 50 μm, in which parameters there were few cracks and delamination on the sintered BCP bioceramics. The flexural strength and the fracture toughness of sintered BCP increased when the Cd/Lt ratio increased from 3.0 to 4.0. However, the flexural strength and the fracture toughness decreased when the Cd/Lt ratio further increased to 5.0. The flexural strength of sintered BCP increased at first and then decreased when the Lt increased from 25 μm to 50 μm, and the fracture toughness and hardness of BCP decreased continually. The flexural strength of sintered BCP showed a maximum value of 113.21 MPa, and the maximum fracture toughness was 0.71 MPa∙m1/2. The elastic modulus and hardness of sintered BCP also reached 24.16 GPa and 3.04 GPa, respectively. The printing surface roughness of BCP bioceramics decreased when the Cd/Lt ratio or Lt increased. The lateral surface roughness decreased with the increase of Cd/Lt ratio, and increased with the increase of Lt. This new result provides a clear printing strategy for fabricating ceramics with high geometrical accuracy and mechanical properties by VPP technique.

Effect Investigation of Ammonium Bicarbonate and Polyethylene Wax as Pore-Forming Agents on the Physicochemical Properties of Macroporous Biphasic Calcium Phosphate Bioceramics Processed by Space-Holder Technique

Effect Investigation of Ammonium Bicarbonate and Polyethylene Wax as Pore-Forming Agents on the Physicochemical Properties of Macroporous Biphasic Calcium Phosphate Bioceramics Processed by Space-Holder Technique

Enhanced mechanical properties and biological responses of SLA 3D printed biphasic calcium phosphate bioceramics by doping bioactive metal elements

Favorable mechanical properties and outstanding bioactivity are necessary for bioceramics used for bone defect repair. The doping of Mg2+ and Fe3+ can improve the mechanical properties and bone regeneration capacity of calcium phosphate ceramics. In this study, magnesia oxide (MgO), ferric oxide (Fe2O3), and iron (Fe) powders are chosen as dopants to enhance biphasic calcium phosphate (BCP) bioceramics, and the MgO-BCP, Fe2O3-BCP, Fe-BCP bioceramics are prepared by stereolithography (SLA) for the first time. The effects of these dopants on the curing behavior of bioceramic slurries, mechanical properties, biodegradation, and cytocompatibility of BCP bioceramics are studied. The addition of 1 wt.% Fe well enhances the flexural strength of BCP from 91.61 MPa to 122.60 MPa sintered at 1250 oC. The addition of 1 wt.% MgO effectively promotes the biodegradation of BCP in simulated body solution (SBF), and enhances the proliferation of mouse pre-osteoblast (MC3T3-E1) cells in vitro. In addition, Fe powder is more suitable as a dopant for SLA 3D printed BCP than Fe2O3 powder, and all the performances of Fe-BCP are better than those of Fe2O3-BCP. The less microstructure defects and slower Fe3+ release rate make Fe-BCP have higher flexural strength and less cytotoxic compared with Fe2O3-BCP. This novel way exhibits beneficial effects of bioactive metal elements on mechanical properties and bioactivity, and indicates SLA 3D printed BCP bioceramic doped with MgO, Fe can be promising candidates for bone defect repair.

In vitro hemocompatibility studies on small-caliber stents for cardiovascular applications.

The doping of biologically meaningful ions into biphasic calcium phosphate (BCP) bioceramics, which exhibit biocompatibility with human body parts, has led to their effective use in biomedical applications in recent years. Doping with metal ions while changing the characteristics of the dopant ions, an arrangement of various ions in the Ca/P crystal structure. In our work, small-diameter vascular stents based on BCP and biologically appropriate ion substitute-BCP bioceramic materials were developed for cardiovascular applications. The small-diameter vascular stents were created using an extrusion process. FTIR, XRD, and FESEM were used to identify the functional groups, crystallinity, and morphology of the synthesized bioceramic materials. In addition, investigation of the blood compatibility of the 3D porous vascular stents was carried out via hemolysis. The outcomes indicate that the prepared grafts are appropriate for clinical requirements.

Design and fabrication of biomimicking radially graded scaffolds via digital light processing 3D printing for bone regeneration.

Scaffolds are an essential component in bone tissue engineering (BTE). However, most of the current BTE scaffolds are homogeneous structures and do not resemble the graded architectures of native bone. In the current study, four types of biomimicking scaffold designs based on gyroid (G) and primitive (P) units with radially graded pore sizes were devised, and scaffolds of these designs with two porosity groups (65 vol% and 75 vol%) were fabricated via digital light processing (DLP) 3D printing using biphasic calcium phosphate (BCP). Scaffolds of the gyroid-gyroid (G-G) design displayed better dimensional accuracy, compressive property, and cell proliferation rate than gyroid-primitive (G-P), primitive-gyroid (P-G), and primitive-primitive (P-P) scaffolds. Subsequently, graded G-G scaffolds with different porosities were fabricated and the relationship between compressive strength and porosity was determined. Furthermore, the sintered BCP bioceramics fabricated via current manufacturing process exhibited excellent biocompatibility and bioactivity, indicating their high potential for BTE.

Construction of Vascularized Tissue Engineered Bone with nHA-Coated BCP Bioceramics Loaded with Peripheral Blood-Derived MSC and EPC to Repair Large Segmental Femoral Bone Defect

The regenerative repair of segmental bone defect (SBD) is an urgent problem in the field of orthopedics. Rapid induction of angiogenesis and osteoinductivity after implantation of scaffold is critical. In this study, a unique tissue engineering strategy with mixture of peripheral blood-derived mesenchymal stem cells (PBMSC) and endothelial progenitor cells (PBEPC) was applied in a 3D-printed biphasic calcium phosphate (BCP) scaffold with highly bioactive nano hydroxyapatite (nHA) coating (nHA/BCP) to construct a novel vascularized tissue engineered bone (VTEB) for rabbit femoral SBD repair. The 2D coculture of PBMSC and PBEPC showed that they could promote the osteogenic or angiogenic differentiation of the cells from each other, especially in the group of PBEPC/PBMSC = 75:25. Besides, the 3D coculture results exhibited that the nHA coating could further promote PBEPC/PBMSC adhesion, proliferation, and osteogenic and angiogenic differentiation on the BCP scaffold. In vivo experiments showed that among the four groups (BCP, BCP-PBEPC/PBMSC, nHA/BCP, and nHA/BCP-PBEPC/PBMSC), the nHA/BCP-PBEPC/PBMSC group induced the best formation of blood vessels and new bone and, thus, the good repair of SBD. It revealed the synergistic effect of nHA and PBEPC/PBMSC on the angiogenesis and osteogenesis of the BCP scaffold. Therefore, the construction of VTEB in this study could provide a possibility for the regenerative repair of SBD.

Effect of silicon or cerium doping on the anti-inflammatory activity of biphasic calcium phosphate scaffolds for bone regeneration.

Biphasic calcium phosphate (BCP) bioceramics composed of hydroxyapatite and β-tricalcium phosphate have attracted considerable attention as ideal bone substitutes for reconstructive surgery, orthopedics, and dentistry, owing to their similar chemical composition to bone mineral and biocompatibility. The addition of trace elements to BCP bioceramics, such as magnesium (Mg), cerium (Ce), and silicon (Si), can alter the physicochemical and biological properties of the resulting materials. To improve the anti-inflammatory activity of a pure BCP scaffold, this study developed a simple wet chemical precipitation and gel-casting method to fabricate microporous BCP scaffolds containing Si or Ce. The BCP scaffolds exhibited interconnected microporous structures with uniform micropores and unequiaxed grains. No changes in the phase composition and microstructure of the scaffolds with the Si or Ce doping were observed. Conversely, Si or Ce doping into the BCP crystal lattice influenced the in vitro biological activity of the scaffolds and the bone-forming ability of the cells cultured on the BCP scaffolds. The results of biological activity assays demonstrated that Ce-BCP promoted cell proliferation and osteogenic differentiation more effectively than the other scaffolds. In particular, Ce-BCP significantly suppressed the expression of bone-active cytokines via the anti-inflammatory and anti-oxidative effects. Therefore, Si- or Ce-doped BCP scaffolds can contribute to providing a new generation of bone graft substitutes.

Microstructures and mechanical properties of biphasic calcium phosphate bioceramics fabricated by SLA 3D printing

Porous biphasic calcium phosphate (BCP) bioceramics are considered to be the most promising bone repair materials in clinical medicine. Stereolithography (SLA) 3D printing can precisely fabricate bioceramic scaffolds with complex porous structure. During this process, how to obtain a suitable sintering procedure for BCP bioceramics by SLA 3D printing is the key to determine the microstructures and mechanical properties, but this is absent. In this present study, we prepared BCP bioceramics with superior densification and mechanical properties by SLA 3D printing, and mainly investigated the effects of sintering temperature and condition on the microstructures and mechanical properties of SLA 3D printed BCP bioceramics for the first time. At the optimized procedure of sintering temperature 1250 °C for 2 h, the 3D printed BCP bioceramics showed uniform shrinkage in all directions, and especially the mechanical properties were close to that of human cortical bone. Furthermore, complex porous BCP scaffolds with high porosity (51.49 %) and compressive strength (8.14 MPa) were successfully obtained. BCP bioceramics greatly promoted the proliferation of MC3T3-E1 cells by the release of Ca and P ion and presented excellent bioactivity. This work proves that SLA 3D printing technology can prepare BCP bioceramics with high mechanical and functional properties, and provides a new route for manufacturing high performance BCP bioceramic scaffolds with complex structure by SLA 3D printing for repairing bone defect in clinical.

Design of macropore structure and micro-nano topography to promote the early neovascularization and osteoinductivity of biphasic calcium phosphate bioceramics

Early neovascularization and osteoinductivity are two key factors to determine the regenerative abilities of biphasic calcium phosphate (BCP) bioceramics in bone repair. Due to the uncontrolled pore structure and large grain size, the biological performances of the conventional BCP bioceramics is restricted to a large extent. Herein, this study attempted to fabricate BCP bioceramics with appropriately uniform macropores and abundant micropores by combining the advantages of the H2O2 foaming method with the microsphere-sintering method, and different sintering methods were adopted to adjust the micro-nano topography. Due to the optimal design of macropore distribution and nano topography, the obtained BCP bioceramics could well trigger and regulate in vitro biological responses, such as degradation, bone-like apatite formation, protein adsorption, cell spreading, angiogenic and osteogenic differentiation. In vivo canine intramuscular implantation further revealed that the nano topography and appropriately uniform macropores might be responsible for the early neovascularization and osteoinductivity of the prepared BCP bioceramics. Collectedly, the neovascularization and osteoinductivity of BCP bioceramics were further enhanced by optimally designing the pore structure and micro-nano topography, which hold huge potential to be an alternative to the gold standard of autogenous bone in bone repairing applications.

Loading of erythropoietin on biphasic calcium phosphate bioceramics promotes osteogenesis and angiogenesis by regulating EphB4/EphrinB2 molecules

Improving osteogenesis and angiogenesis using different cells and drugs is critical in the field of bone tissue engineering. Recent research has found that erythropoietin (EPO) plays an important role in both osteogenesis and angiogenesis. In this study, we grafted polydopamine and EPO onto the surface of biphasic calcium phosphate. The characterization and release property of the modified bioceramics were assessed. Cell proliferation, expression of osteoblastic and endothelial markers, and EphB4/EphrinB2 molecules were investigated while employing co-cultures of two different cells [rat vein endothelial cells (VECs) and rat bone marrow mesenchymal stromal cells (BMSCs)]. The modified bioceramics were finally implanted into the SD rats’ femurs and followed by investigating the bone defect repair efficacy and the expression of EphB4/EphrinB2 molecules in vivo. The results indicated that the modified bioceramics could control the release of EPO continuously. The osteogenesis and angiogenesis were improved along with the increased expression of EphB4/EphrinB2 molecules. The expression of EphB4/EphrinB2 molecules was also significantly increased in vivo and the bone defect was repaired effectively. Overall, our findings demonstrated that EPO loading on biphasic calcium phosphate bioceramics could promote both osteogenesis and angiogenesis. The results suggest that EphB4/EphrinB2 may be crucial in the process.Graphical abstract

Optimal regenerative repair of large segmental bone defect in a goat model with osteoinductive calcium phosphate bioceramic implants

So far, how to achieve the optimal regenerative repair of large load-bearing bone defects using artificial bone grafts is a huge challenge in clinic. In this study, a strategy of combining osteoinductive biphasic calcium phosphate (BCP) bioceramic scaffolds with intramedullary nail fixation for creating stable osteogenic microenvironment was applied to repair large segmental bone defects (3.0 cm in length) in goat femur model. The material characterization results showed that the BCP scaffold had the initial compressive strength of over 2.0 MPa, and total porosity of 84%. The cell culture experiments demonstrated that the scaffold had the excellent ability to promote the proliferation and osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells (BMSCs). The in vivo results showed that the intramedullary nail fixation maintained the initial stability and structural integrity of the implants at early stage, promoting the osteogenic process both guided and induced by the BCP scaffolds. At 9 months postoperatively, good integration between the implants and host bone was observed, and a large amount of newborn bones formed, accompanying with the degradation of the material. At 18 months postoperatively, almost the complete new bone substitution in the defect area was achieved. The maximum bending strength of the repaired bone defects reached to the 100% of normal femur at 18 months post-surgery. Our results demonstrated the good potential of osteoinductive BCP bioceramics in the regenerative repair of large load-bearing bone defects. The current study could provide an effective method to treat the clinical large segmental bone defects.

Sintering parameters study of a biphasic calcium phosphate bioceramic synthesized by alcoholic sol-gel technique

In the sintering of biphasic calcium phosphate bioceramics (BCP) can occur phases transformations accompanied by a sudden thermal expansion due to different coefficients of thermal expansion of each phase, which generates internal stress concentrations inducing undesired cracks within the sample. Therefore, this work aimed to study the sintering parameters of a BCP, composed of hydroxyapatite (HAp) and β-tricalcium phosphate (β-TCP), synthesized by the alcoholic sol-gel technique, in order to evaluate the better conditions for avoiding defect generation. BCP powders were uniaxially cold-pressed at 300 MPa and air-sintered at 1070 °C/2 h (BCP1070 sample) and 1130 °C/2 h (BCP1130 sample), with heating rates of 10 °C/min and 5 °C/min, respectively. Samples were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, relative density determination, Vickers hardness test, and nanohardness tests. The results displayed that the assessed sintering parameters were suitable for promoting a satisfactory particle consolidation. The transformation from HAp to β-TCP occurred simultaneously with grain growth and material densification under all conditions. The mechanical tests revealed that BCP1070 and BCP1130 samples have different behaviour when analyzed micro or nanostructurally. But, the heating rate (10 °C/min) combined with the sintering temperature (1070 °C) anabled to obtain a suitable sinterability with samples presenting smaller grain size and without defects. Further, it kept the microporosity which is an essential property for application in bioceramic materials.

Excellent Osteoinductivity of Biphasic Calcium Phosphate Bioceramics with the Optimal Design of Pore Size Distribution and Micro-Nano Topography

Further enhance the bioactivity and osteoinductivity of biphasic calcium phosphate (BCP) bioceramics to meet the requirements of regenerative medicine is still a hot topic. Due to the uncontrolled pore structure and large grain size, the osteoinductivity of the conventional BCP bioceramics is restricted to a large extent. Herein, this study introduced a novel pore foaming method to fabricate BCP bioceramics with appropriately ordered macropores and abundant micropores by combing the advantages of the microsphere-sintering method with the H2O2 gas foaming method. Moreover, different sintering methods were adopted to adjust the micro-nano topography of BCP bioceramics. Due to the optimal design of pore size distribution and nano topography, the obtained BCP bioceramics could well trigger and regulate in vitro biological responses, such as degradation, bone-like apatite formation, protein adsorption, cell behaviors, angiogenic and osteogenic differentiation. In vivo canine intramuscular implantation further confirmed that the nanotopography and appropriately ordered pore structure might be responsible for the excellent neovascularization and osteoinductivity of the obtained BCP bioceramics. Collectedly, the osteoinductivity of BCP bioceramics was further enhanced by optimally designing pore structure and micro-nano topography, which hold huge potential to be a potential alternative to the gold standard of autogenous bone in bone repairing applications.

Restoring Facial Contour and Harmony Using Biphasic Calcium Phosphate Bioceramics.

Background:The restoration of facial contour is one of the pillars for the treatment of facial disharmonies and deformities. Fat transplantation and fillers have been widely used to improve the positioning of soft tissues, which are, however, directly related to the conditions and positioning of the underlying bone tissue. Recontouring of the latter has been performed using osteotomies and several types of bone grafts or biomaterials, as inlay or onlay grafts/implants. Here, biphasic calcium phosphate bioceramics were applied in a series of cases, their long-term results are shown, and their advantages, discussed.Methods:A retrospective analysis of 20 patients, who were subjected to facial recontour with onlay implants of biphasic calcium phosphate bioceramics, is reported. Patients were seeking to improve facial harmony due to congenital deformities, trauma, tumor resection or signs of aging, and were followed for up to 16 years. Clinical data, radiographic images, and information regarding pain and other findings were retrieved from medical records.Results:Six patients were men and 14 were women. Their ages ranged from 19 to 64 years. Bioceramics were implanted under the periosteum through external or intraoral incisions. Some patients underwent combined procedures, such as rhinoplasties or facial lifting. None of the patients presented exacerbated inflammation or pain. One of them had infection in the intraoral incision, which was resolved with medication.Conclusion:All patients had improved facial contours following the use of bio-ceramics to augment bone tissue and presented stable results at long-term evaluation.

Physical characterization of biphasic bioceramic materials with different granulation sizes and their influence on bone repair and inflammation in rat calvaria

Biphasic calcium phosphate bioceramics (BCP) consist of a mixture of hydroxyapatite (HA) and beta-tricalcium phosphate (β-TCP) within the same particle. Due to their osteoconductive properties, biocompatibility and resemblance to natural bone, these materials have become a promising and suitable alternative to autologous bone grafting. First, the topography characteristics, specific surface area, and total pore volume of BCP were evaluated using scanning electron microscopy and the BET and BJH methods. Next, this study aimed to evaluate the intensity of the inflammatory process and the bone neoformation capacity of various particle sizes of BCP in the repair of critical defects in the calvaria of rats. A xenogeneic biomaterial was used in the control group. After 30, 60, and 90 days, the animals were euthanized, followed by the processing of the samples to measure the intensity of inflammatory infiltrates and the areas of bone neoformation. Our results indicate that no considerable differences were observed in the inflammatory scores in sites treated with distinct BCP grain sizes. A greater area of bone neoformation was measured in the xenogeneic group at all analysis times, with no substantial differences in bone formation between the BCP particle size in the range of 250–500 µm and 500–1000 µm.

The Immunohistochemical Study of Periodontal Tissues Regenerated by Nano Calcium Phosphate Bioceramics

The aim of the experiment was to study the immunohistochemical reaction the periodontal tissues regenerated by nano biphasic calcium phosphate bioceramics (NBCP). Two lateral third incisors were randomly selected and operated as experimental group in two beagle dogs. As control the contralateral third incisors of the same jaw were done nothing. In experimental group, alveolar bone defects were made surgically at the labial aspects of the teeth. After root conditioning, the defects were filled with NBCP. 16 weeks after operation, the dogs were killed. The immunohistochemistry examination was used to observe the newly formed periodontium in the experimental group and the normal periodontium in the control group. The positive expressions of osteocalcin (OCN) in newly formed periodontium were the same to that in normal periodontal tissues.

Bioactivity of Biphasic Calcium Phosphate Granules, the Control of a Needle-Like Apatite Layer Formation for Further Medical Device Developments.

Biphasic calcium phosphate (BCP) bioceramics (hydroxyapatite/tricalcium phosphate, or HA/TCP) for tissue engineering and drug delivery systems is a unique know-how. A mechanical mixture of HA and TCP does not lead to such bioactive ceramics. The wet elaboration conditions of calcium-deficient apatite (CDA) or CDHA, followed by sintering, converts it into TCP and HA. The dissolution precipitation of nano-sized needle-like crystals at the surface of BCP occurs on time at body temperature. Combining several technics of characterization [scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive x-ray spectroscopy (EDX), Brunauer-Emmett-Teller method (BET), chemical analysis, x-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR)], we demonstrated an evolution on time of the HA/β-TCP. The current paper describes the crystallographic evolution of initial β-TCP rhombohedral crystallographic structure to microsized needle-like layer corresponding to apatitic TCP form. This phenomenon leads to an increase of the HA/TCP ratio, since hexagonal apatitic TCP is similar to hexagonal HA. However, the Ca/P ratio (reflecting the chemical composition HA/TCP) remains unchanged. Thus, the high reactivity of BCP involves dynamic evolution from rhombohedral to hexagonal structure, but not a chemical change. The dynamic process is reversible by calcination. These events are absolutely necessary for smart scaffolds in bone regeneration and orthobiology.

Recent Advances of Biphasic Calcium Phosphate Bioceramics for Bone Tissue Regeneration.

Biphasic calcium phosphate bioceramics consist of an intimate mixture of hydroxyapatite (HA) and beta-tricalcium phosphate (β-TCP) in varying ratios. Due to their biocompatibility, osteoconductivity, and safety in in vitro, in vivo, and clinical models, they have become promising bone substitute biomaterials and are recommended for use as alternatives for or as additives in bone tissue regeneration in various orthopedic and dental applications. Many studies have demonstrated the potential uses of BCP bioceramics as scaffolds for tissue engineering. Here, we highlight the recent advances in the uses of BCP bioceramics and functionalized BCPs for bone tissue regeneration.

Minimally invasive implantation and decreased inflammation reduce osteoinduction of biomaterial.

Surgical trauma of biomaterial implantation significantly influences the immune system and the biological effects of biomaterials. Minimally invasive surgery has become a trend of clinical development but violating the concept of osteoimmunomodulation will hinder the biological effects of materials. Our study focused on biphasic calcium phosphate (BCP), the ectopia osteoinductive materials, filling the research blank of the significance of adaptive immunity crosstalk with bone biomaterials, and improving the interaction mechanism between bone biomaterials and immune response.Methods: The BCP bioceramics were implanted by conventional and minimally invasive methods in the gastrocnemius wild-type or T cells depleted mice to test the effect of ectopia osteoinduction. Moreover, flow cytometry was used to detect immune responses, T cell sorting and Western Blot molecular biology experiments, and transwell assays migration of mesenchymal stem cells (MSCs).Results: We found that BCP, an implantable osteoinductive material, could not activate the adaptive immune response mediated by T cells after minimally invasive surgery. Further studies revealed that under the conventional non-minimally invasive BCP implantation, a positive correlation existed between T cell recruitment and the infiltration and osteogenic differentiation of MSCs. Interestingly, after BCP was implanted by minimally invasive surgery or implanted in T cell depleted mice, MSCs infiltration and osteogenic differentiation were significantly reduced, and BCP could not achieve the biological effects of ectopia ossification. Finally, we confirmed that a certain extent inflammatory stimulation activated the adaptive immune response mediated by T cells, up-regulated the nuclear factor-κB (NF-κB) signal in T cells, released a large amount of chemokine C-C motif chemokine ligand 5(CCL5) to recruit MSCs to the surrounding material, and finally achieved the ideal effect of osteoinduction.Conclusion: From experimental research and clinical surgery, this study discovered that the T cells are indispensable in the ectopia ossification mediated by osteoinductive materials, put forward and confirmed the surgery method as a key variable factor restricting the application effect of biological materials, enriched the key mechanism of adaptive immunity in osteoimmunomodulation, and laid a theoretical foundation for the development of osteoinductive materials and bone tissue regeneration.

Novel nano-sized biphasic calcium phosphate bioceramics (β-CPP/β-TCP) derived of lime mud waste

In this work, novel BCP (β-CPP, β-Ca2P2O7/β-TCP, β-Ca3(PO4)2) bioceramics have been synthesized by wet chemical precipitation using lime mud waste from cellulose industry as inexpensive sustainable CaCO3 precursor source. The synthesized BCP bioceramics have been characterized regarding to X-ray diffraction (XRD), Rietveld refinement, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The results indicated that the amounts of the phases β-CPP and β-TCP in the biphasic mixtures depend on the different HNO3 molar concentrations used in the synthesis. In addition, the BCP (β-CPP/β-TCP) powders exhibited average crystallite size in the range of 55.56 to 59.85 nm. Such novel BCP nanopowders produced by using CaCO3 from lime mud waste have high potential for biomedical applications.