Synthesis of Spongy-Like Mesoporous Hydroxyapatite from Raw Waste Eggshells for Enhanced Dissolution of Ibuprofen Loaded via Supercritical CO2

The use of cheaper and recyclable biomaterials (like eggshells) to synthesize high purity hydroxyapatite (HAp) with better properties (small particle size, large surface area and pore volume) for applications (in environmental remediation, bone augmentation and replacement, and drug delivery systems) is vital since high-purity synthetic calcium sources are expensive. In this work, pure and mesoporous HAp nanopowder with large pore volume (1.4 cm³/g) and surface area (284.1 m²/g) was produced from raw eggshells at room temperature using a simple two-step procedure. The control of precursor droplets could stabilize the pH value of the reaction solution, because of the size of the needle (of the syringe pump used for precursor additions) leading to production of HAp with high surface area and pore size. The as-produced HAp revealed high ibuprofen (as a model drug) loading (1.38 g/g HAp), enhanced dissolution and controllable release of the drug via solute-saturated supercritical carbon dioxide.     

Synthesis and characterization of biomimetic hydroxyapatite/sepiolite nanocomposites

Natural fibrous sepiolite with a high surface area, negative surface charge and porous structure is promising for hydroxyapatite (HAp) mineralization since the clay is naturally abundant and biocompatible. In this paper, the use of fibrous sepiolite as a template for growth of HAp nanocrystals was reported for the first time. Carbonated HAp nanorods with dimensions of 20-60 nm in length and 10-20 nm in diameter were successfully grown on the sepiolite surface with a preferred orientation to the c-axis. The critical nucleus radius of HAp in the presence of natural sepiolite was estimated as 0.296-0.312 nm. Strong acid-activation increased the specific surface area of the sepiolite by 205% and also transformed the sepiolite to silica fiber with an elastic modulus being 395% of the original value. The novel HAp/acid-activated sepiolite biocomposite has a specific surface area of 182 m2 g(-1) and an elastic modulus of over 20 GPa, considerably higher than those of the HAp synthesized without sepiolite. Such hierarchically assembled HAp/sepiolite biocomposites with controlled size and improved modulus open a new way to expand the applications of naturally abundant clays in biological load-bearing devices.     

Facile control of hydroxyapatite particle morphology by utilization of calcium carbonate templates at room temperature

Hydroxyapatite (HAp, Ca₁₀(PO₄)₆(OH)₂) particles are widely used in orthopedic applications due to their chemical resemblance to the inorganic component of bone tissue. Since physical and chemical properties of HAp particles influence bone regeneration, various synthesis techniques were developed to precisely control the particle properties. However, most of these techniques required high reaction temperatures, which limited the spectrum of obtained HAp particle morphologies. In this study, ellipsoidal, bowknot-like and spherical calcium carbonate (CaCO₃) particles were utilized as solid templates to control the morphology of HAp particles (core@shell, CaCO₃@HAp) under ambient conditions. Since CaCO₃ templates had different properties, i.e. morphology, polymorph and surface area, they induced HAp formation with different efficacies, where ellipsoidal vaterite and spherical calcite particles exhibited higher CaCO₃-to-HAp conversion compared to bowknot-like aragonite particles. In vitro experiments showed that proliferation of human bone cells (hFOB) was higher upon their interaction with ellipsoidal and spherical CaCO₃@HAp particles compared to bowknot-like CaCO₃@HAp particles. These findings highlighted CaCO₃ particles as promising hard templates to control the morphology of CaCO₃@HAp particles under ambient conditions for orthopedic applications.     

In situ synthesis and characterization of nano-size hydroxyapatite in poly(vinyl alcohol) matrix

Hydroxyapatite (HAp) crystals were prepared via an in situ biomimetic process in the presence of poly(vinyl alcohol) (PVA). The effect of polymer amount and its molecular weight on the physical properties of the HAp crystals were investigated. X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR) analysis, confirmed the formation of the crystalline HAp at room temperature. Microstructural features such as size and morphology of the resulting HAp samples were characterized using BET, scanning and transmission electron microscopy. The results indicate that the development (size and shape) of the HAp nanocrystals precipitated in an aqueous solution of PVA was influenced by the molecular weight of the polymer in such a way that smallest crystallite size was observed in the case of PVA with the highest molecular weight. It is believed that the HAp formation was initiated through the interaction of Ca²⁺ ions with the negative side groups on the polymer surface. The larger number of reaction sites in the PVA polymer with higher molecular weight led to a higher number of HAp nuclei and therefore smaller crystallite size.     

Increasing the Crystallinity of Hydroxyapatite Nanoparticles in Composites Containing Bioaffinitive Organic Polymers by Mechanical Stressing

Crystallinity of hydroxyapatite (HAp) in bioaffinitive disperse systems was increased by a wet mechanochemical treatment at room temperature. Silk fibroin (SF) and/or hyaluronic acid (HYA) were used as bioorganics. With the mechanochemical treatment, the crystallite size and the aspect ratio of HAp decreased and became closer to that of swine trabecular bone. Mechanochemical effects on the HAp nanocrystals were discussed in terms of coherent chemical interaction between HAp and bioorganics.     

Efficacy for Whitlockite for Augmenting Spinal Fusion

Whitlockite (WH) is the second most abundant inorganic component of human bone, accounting for approximately 25% of bone tissue. This study investigated the role of WH in bone remodeling and formation in a mouse spinal fusion model. Specifically, morphology and composition analysis, tests of porosity and surface area, thermogravimetric analysis, an ion-release test, and a cell viability test were conducted to analyze the properties of bone substitutes. The MagOss group received WH, Group A received 100% beta-tricalcium phosphate (β-TCP), Group B received 100% hydroxyapatite (HAp), Group C received 30% HAp/70% β-TCP, and Group D received 60% HAp/40% β-TCP (n = 10 each). All mice were sacrificed 6 weeks after implantation, and micro-CT, hematoxylin and eosin (HE) staining, and Masson trichome (MT) staining and immunohistochemistry were performed. The MagOss group showed more homogeneous and smaller grains, and nanopores (<500 nm) were found in only the MagOss group. On micro-CT, the MagOss group showed larger fusion mass and better graft incorporation into the decorticate mouse spine than other groups. In the in vivo experiment with HE staining, the MagOss group showed the highest new bone area (mean: decortication group, 9.50%; A, 15.08%; B, 15.70%; C, 14.76%; D, 14.70%; MagOss, 22.69%; p < 0.0001). In MT staining, the MagOss group demonstrated the highest new bone area (mean: decortication group, 15.62%; A, 21.41%; B, 22.86%; C, 23.07%; D, 22.47%; MagOss, 26.29%; p < 0.0001). In an immunohistochemical analysis for osteocalcin, osteopontin, and CD31, the MagOss group showed a higher positive area than other groups. WH showed comparable bone conductivity to HAp and β-TCP and increased new bone formation. WH is likely to be used as an improved bone substitute with better bone conductivity than HAp and β-TCP.     

羟基磷灰石生物医用陶瓷材料的研究与发展

自然骨的主要无机矿物成分为纳米羟基磷灰石[Ca10（PO4）6（OH）2，HAP]针状晶体。人工合成的羟基磷灰石材料具有与自然矿物相似的结构，形态，成分，表现出良好的生物相容性和生物活性，广泛应用于医药和牙科领域。对近年来羟基磷灰石生物材料的制备和应用进行了综述。     

Development of bone scaffold using Puntius conchonius fish scale derived hydroxyapatite: Physico-mechanical and bioactivity evaluations

Naturally derived Hydroxyapatite (HAp) from fish scale is finding wide applications in the development of bone scaffold to promote bone regeneration. But porous HAp scaffold is fragile in nature making it unsuitable for bone repair or replacement applications. Thus, it is essential to improve the mechanical property of HAp scaffolds while retaining the interconnected porous structure for tissue ingrowth in vivo. In this study solvent casting particulate leaching technique is used to develop novel Puntius conchonius fish scale derived HAp bone scaffold by varying the wt.% of the HAp from 60 to 80% in PMMA matrix. Physico-chemical, mechanical, structural and bioactive properties of the developed scaffolds are investigated. The obtained results indicate that HAp-PMMA scaffold at 70?wt % HAp loading shows optimal properties with 7.26?±?0.45?MPa compressive strength, 75?±?0.8% porosity, 8.0?±?0.68% degradation and 190?±?11% water absorption. The obtained results of the scaffold can meet the physiological demands to guide bone regeneration. Moreover, in vitro bioactivity analysis also confirms the formation of bone like apatite in the scaffold surface after 28 days of SBF immersion. Thus, the developed scaffold has the potential to be effectively used in bone tissue engineering applications.     

Influence of concentration of hydroxyapatite surface modifier agent on bioactive composite characteristics

The characterization of chitosan – hydroxyapatite (CH – HAp) composite sponges prepared via freeze-drying methodology is reported in this study. Stearic acid (SA), added as a surface modifier of the HAp nanoparticles, induced changes in the TG/DTG results, particle size distribution and particle morphology. Composite sponges prepared with SA coated HAp demonstrated enhanced biocompatibility and structural properties, as compared to the composites prepared with uncoated HAp. SA coating modified the morphology of the composite, promoting a better dispersion of HAp particles within the composite sponges, and better homogeneity of the polymeric cover with HAp particles. The viability of the composites for cell culture applications was analyzed, and the results suggest that the sponges are biocompatible. Therefore, SA proved to be a good candidate for surface coating of HAp nanoparticles prevent agglomerations, and could be used effectively in the preparation of biocompatible composite sponges with chitosan.     

Template-directed hydrothermal synthesis of dandelion-like hydroxyapatite in the presence of cetyltrimethylammonium bromide and polyethylene glycol

A template-directed synthetic method, using surfactant cetyltrimethylammonium bromide (CTAB) as a template and co-surfactant polyethylene glycol (PEG600) as a co-template under hydrothermal conditions, has been applied to obtain dandelion-like HAp. The morphology, size, crystalline phase, chemical composition, physical characteristics, and thermal behavior of the product were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Fourier ransform infrared spectroscopy (FTIR), induced coupled plasma spectroscopy (ICP), BET (Brunauer, Emmett, and Teller) method, and simultaneous thermal analysis (STA). SEM and TEM observations showed in the presence of CTAB and a certain concentration of PEG600 (30%) HAp crystals have a uniform dandelion-like morphology with a diameter of about 80–150 nm and aspect ratio of about 20 for each tooth. Dandelion-like HAp crystals have a high surface area of 88 m² g⁻¹ showing potential applications. The template action of CTAB and co-template action of PEG600 are also discussed.     

Extraction and characterization of hydroxyapatite-based materials from grey triggerfish skin and black scabbardfish bones

The conversion of food industry by-products to compounds with high added value is nowadays a significant topic, for social, environmental, and economic reasons. In this paper, calcium phosphate-based materials were obtained from black scabbardfish (Aphanopus carbo) bones and grey triggerfish (Balistes capriscus) skin, which are two of the most abundant fish by-products of Madeira Island. Different calcination temperatures between 400 and 1000°C were employed. Materials obtained from calcination of bones of black scabbard fish were composed by homogeneous mixtures of hydroxyapatite (Ca₁₀(PO4)₆(OH)₂, HAp) and β-tricalcium phosphate (β-Ca₃(PO₄)₂, β-TCP). Because of the high biocompatibility of HAp and the good resorbability of β-TCP, these natural biphasic materials could be very relevant in the field of biomaterials, as bone grafts. The ratio between HAp and β-TCP in the biphasic compound was dependent on the calcination temperature. Differently, the material obtained from skin of grey triggerfish contained HAp as the main phase, together with small amounts of other mineral phases, such as halite and rhenanite, which are known to enhance osteogenesis when used as bone substitutes. In both cases, the increase of calcination temperature led to an increase in the particles size with a consequent decrease in their specific surface area. These results demonstrate that from the fish by-products of the most consumed fishes in Madeira Island it is possible to obtain bioceramic materials with tunable composition and particle morphology, which could be promising materials for the biomedical field.     

Fabrication of Hydroxyapatite with Bioglass Nanocomposite for Human Wharton’s-Jelly-Derived Mesenchymal Stem Cell Growing Substrate

Recently, composite scaffolding has found many applications in hard tissue engineering due to a number of desirable features. In this present study, hydroxyapatite/bioglass (HAp/BG) nanocomposite scaffolds were prepared in different ratios using a hydrothermal approach. The aim of this research was to evaluate the adhesion, growth, viability, and osteoblast differentiation behavior of human Wharton’s-jelly-derived mesenchymal stem cells (hWJMSCs) on HAp/BG in vitro as a scaffold for application in bone tissue engineering. Particle size and morphology were investigated by TEM and bioactivity was assessed and proven using SEM analysis with hWJMSCs in contact with the HAp/BG nanocomposite. Viability was evaluated using PrestoBlue^TM assay and early osteoblast differentiation and mineralization behaviors were investigated by ALP activity and EDX analysis simultaneously. TEM results showed that the prepared HAp/BG nanocomposite had dimensions of less than 40 nm. The morphology of hWJMSCs showed a fibroblast-like shape, with a clear filopodia structure. The viability of hWJMSCs was highest for the HAp/BG nanocomposite with a 70:30 ratio of HAp to BG (HAp70/BG30). The in vitro biological results confirmed that HAp/BG composite was not cytotoxic. It was also observed that the biological performance of HAp70/BG30 was higher than HAp scaffold alone. In summary, HAp/BG scaffold combined with mesenchymal stem cells showed significant potential for bone repair applications in tissue engineering.     

Polymer assisted isolation of hydroxyapatite from Thunnus obesus bone

The combination of micro and nanostructured hydroxyapatite (HAp) was isolated from Thunnus obesus bone via thermal calcination method in the presence of polymers such as poly ethylene glycol (PEG), poly (ethylene glycol)-block-poly (propylene glycol)-block-poly (ethylene glycol) (PEG-PPG-PEG) and poly vinyl alcohol (PVA). The thermal stability, crystalline phase, chemical composition and morphology of the derived HAp were characterized by thermal gravimetric analysis, X-ray diffraction analysis, Fourier transform infrared spectroscopy and field emission scanning electron microscopy analysis. The physicochemical characteristic examination revealed that derived HAp was coherent with standard HAp data. Moreover, FE-SEM depicted significant difference in the crystal size of HAp derived with thermal calcination, with and without added polymers. The crystallinity of HAp isolated in the presence of polymer was lower than that obtained in the absence of polymers. The biocompatibility of the derived HAp crystals was checked with MC3T3-E1 osteoblastic cells by MTT assay and Hoechst-33342 staining. The biocompatibility of HAp derived by polymer assisted thermal calcination method revealed that it is less toxic as compared to HAp derived in the absence of polymer. As an inference, polymer assisted thermal calcination derived HAp is good in terms of the presence of combined micro and nanostructured HAp and its low toxicity will bring about new orthopaedic applications.     

An aqueous synthesis of photocatalyst by selective dissolution of titanium oxide/hydroxyapatite composite

A novel synthesis method of a highly active photocatalyst was proposed. Titanium dioxide (TiO₂) nano-particles were prepared by three-step procedure, precipitation of hydroxyapatite (HAp) on TiO₂ particles, heat treatment of the TiO₂/HAp composites, and acid treatment in hydrochloric acid. The unique point of this procedure is the selective dissolution of HAp to obtain exposed TiO₂ surfaces. The HAp precipitation was achieved by stirring TiO₂ powders in the mixtures of Ca(NO₃)₂ and NH₄H₂PO₄ aqueous solutions at pH 8.5. Then, the heat-treated TiO₂/HAp composites were treated with hydrochloric acid. The precipitated HAp avoided the direct contact of TiO₂ particles and suppressed the phase transformation from anatase-to-rutile >200 °C. The HAp also suppressed a decrease of specific surface area of TiO₂ during the heat treatment. The photocatalytic activities were evaluated from an absorbance decrease of methylene blue (MB) under ultraviolet (UV) irradiation. The MB photodecomposition was approximated to the first-order reaction and the reaction rate constants of the obtained TiO₂ powders heated at various temperatures were higher than those of conventional TiO₂ powders heated at same temperatures. The enhanced photocatalytic activity is attributed to the suppression effects for the phase transformation to rutile phase and the decreasing of specific surface area in the heat treatment.     

Structural and biological properties of novel Vanadium and Strontium co-doped HAp for tissue engineering applications

The development of novel bioactive materials with improved physical and biological properties is crucial for advancing tissue engineering applications. In this study, we synthesized a Vanadium and Strontium co-doped hydroxyapatite (V–Sr:HAp) nanoparticle intending to enhance the performance of pure HAp. The V–Sr:HAp nanoparticles were synthesized using a microwave-assisted reflux condensation method, and their structural and chemical characteristics were investigated using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The morphology and elemental composition of the nanoparticles were examined through scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDX). The XRD analysis confirmed the presence of characteristic peaks of HAp in each sample. SEM images revealed well-connected and highly agglomerated small sphere-like morphology in both pure HAp and V–Sr:HAp nanoparticles. The Vickers hardness test demonstrated the improved mechanical strength in V–Sr:HAp compared to pure HAp. Antibacterial efficacy was evaluated using an agar diffusion test, which showed enhanced antibacterial activity in the co-doped HAp samples against S. aureus and P. aeruginosa. Moreover, the Ca–P deposition rate on the surface of the co-doped HAp samples during biomineralization was higher. Hemolysis assay results have indicated compatibility of both pure HAp and V–Sr:HAp with human blood (<5% lysis). The results of cell viability tests demonstrate that the V and Sr co-doped HAp samples do not exhibit any cytotoxic effects and instead promote cell proliferation. Overall, the incorporation of V and Sr metal ions into HAp presents a promising bio-functional tool for tissue engineering applications, offering improved mechanical and antibacterial properties.     

Bioactivity and osteoinductivity of glasses and glassceramics and their material determinants

Bioactive glasses and glassceramics have been used in both bone repair and tissue engineering applications. An important feature of bioactive glasses and glassceramics, which enables them to be used for desired application, is their biological activity. This activity is manifested by the ability of these materials to form a stable bond with bone tissue (bioactivity) and, in some cases, their ability to promote/initiate osteogenesis (osteoinductivity). A stable material-bone bonding (i.e. bioactivity) results from specific material surface reactions leading to hydroxyapatite (HAp) formation on the material surface. Bioactivity of materials is often evaluated in vitro and the ability of materials to form HAp-like surface layer is usually studied after immersion/incubation of materials in simulated body fluid (SBF). Biological activity of materials can be also defined as their ability to induce specific cell responses leading to faster regeneration of bone tissue. It may be manifested by materials supporting bone cell attachment, proliferation and differentiation (biocompability/osteconductivity), and/or by materials inducing/promoting the expression of multiple bone-related genes that drive osteogenesis (osteoinductivity). Osteoinductivity is often verified in vivo by the materials capability to form bone at etopic (i.e. extraskeletal) sites. However, a lot of in vitro call-based experiments are now offered to determine osteoinductive properties of biomaterials. This review focuses on the silica-based glasses and glass-ceramics, in particular, the sol-gel derived ones, and summarizes their bioactivity and osteoinductivity as major determinants of their biological activity. We highlight the chemistry of bioglasses and glassceramics that affects not only the formation of a stable implant/bone bonding by HAp layer, but also drives the cell response in vitro and in vivo.     

Pilot-scale manufacturing of phase-pure and highly crystalline hydroxyapatite: Lessons learned and process protocols

The recognition of hydroxyapatite (HAp) as the major bone mineral triggered significant research in bone tissue engineering applications. Although laboratory-scale development involves the synthesis of HAp in different routes, scalability with uncompromised quality remains a major challenge. This article reports a large-scale wet precipitation-based synthesis of phase-pure HAp using indigenously customized stirred tank reactors. The different synthesis parameters, like pH, reaction time, stirring rate, precursor addition, were tailored, together with the post-synthesis mechano-chemical treatment (aging induced Ostwald ripening) and calcinations, as the technology is matured to manufacture HAp powders in large volume. At least three batches of HAp were produced in the pilot-scale reactor with reproducible values of phase purity, compositional fingerprint, particle size distribution, flowability, etc. The post-calcination bluish tint was strategically addressed by adopting a proprietary calcination protocol. This batch process can produce around 200 kg/month of phase-pure and highly crystalline (91–94%) HAp using stirred tank reactors of different working volumes. Extensive scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses reveal the particle size of as-synthesized HAp powders with hexagonal crystal structure in the range of 20.47 ± 4.95 nm , while individual crystallite size in range of 22.3 ± 3.2 nm (XRD based Debye-Scherrer analysis). TEM-based SADP analysis confirms the highly crystalline hexagonal structure of as-synthesized HAp. The spray-dried powders with spherical shape having narrow size distribution (35–40 μm) could also be manufactured in large batches. The spray-dried HAp powders could be coated on clinically used stainless steel femoral stem implants using atmospheric plasma spray coating technique.     

Simultaneous co-substitution of Sr2+/Fe3+ in hydroxyapatite nanoparticles for potential biomedical applications

In human, strontium (Sr) follows the same physiological pathway as calcium and thus could be used for improving the bioactivity and osteoconductivity of hydroxyapatite (HAp) in bone tissues. Similarly, iron (Fe) can potentially play an important role in bone remodeling due to its magnetic properties. Therefore, the current study was aimed to simultaneously co-substitute Sr²⁺/Fe³⁺ in HAp nanoparticles for various potential biomedical applications. The Sr²⁺/Fe³⁺ co-substituted HAp nanoparticles were systematically synthesized through sonication-assisted aqueous precipitation method. The as-synthesized nanoparticles were evaluated for different physicochemical and biological properties. X-ray diffraction (XRD) patterns of Sr²⁺/Fe³⁺ co-substituted HAp nanoparticles confirmed their phase purity and showed hexagonal-like structure. Scanning electron microscope (SEM) micrographs showed an agglomerated rod-like morphology of HAp nanoparticles which contained pores consisted of small spheroids. The nanoparticles displayed magnetization (Ms) reliance on the loading level of mole % (X?=?Fe³⁺) and exhibited tunable porosity and microhardness (Hv) upon heat treatment. The nanoparticles showed less than 5% hemolysis demonstrating high blood compatibility with high in vitro bioactivity performance. The multifunctional properties of synthesized nanoparticles make them a potential candidate for various biomedical applications; including bone grafting and guided bone regeneration, targeted drug delivery, magnetic resonance imaging, and hyperthermia based cancer treatment.     

Biphasic bone graft prepared using a gel-foaming technique

Synthetic bone graft has gained considerable attention because of an increase in the aged population. In the present study, a biphasic bone graft composed of hydroxyapatite (HAp) and calcium sulfate (CS) is prepared using a gel-foaming technique. The gel is prepared at a temperature as low as 35 °C; many pores are introduced into the gel through an agitation process. The foamed gel can be cut into any shape and size. After sintering, the porosity of the biphasic bone graft is approximately 70%. Depending on the HAp/CS ratio, the amount of macropores and micropores can be tailored. The macropores of approximately 130 μm diameter are interconnected with each other through openings of 40 μm size. The biphasic bone graft exhibits no cytotoxicity; preosteoblast cells can adhere and proliferate on the surface of the fabricated bone graft. However, migration of these cells into the bone graft is considerably limited in the in vitro study. When the biphasic bone graft is implanted into the distal femur of rats, with the combined effect of osteoblast and osteoclast cells, more than 90% of the bone graft is degraded after 3 months. New trabeculae bone and bone marrow are observed within the bone defect. The HAp/CS composite can thus be used as degradable bone grafts.     

Sintering behavior and mechanical properties of hydroxyapatite ceramics prepared from Nile Tilapia (Oreochromis niloticus) bone and commercial powder for biomedical applications

In this work, Nile tilapia (Oreochromis niloticus) bone was calcined at 800 °C for 5 h in an air atmosphere to obtain hydroxyapatite powder (FB powder). The elemental composition, phase structure, and morphology of the FB powder were investigated and compared with commercial hydroxyapatite powder (SM powder). The FB-powder exhibited 1.01 at. % of Mg while the SM-powder showed Mg in ppm-level. Carbonate groups were detected in the two powders. Both HAp and β-tricalcium phosphate (β-TCP) structures were found in the FB powder, but the SM powder exhibit only the HAp phase. Irregular-shaped particles were observed in the FB powder. After the two HAp powders were sintered at 1200 °C and 1250 °C for 2 h (FB-1200, FB-1250, SM-1200, and SM-1250), the β-TCP intensity peaks of the FB-ceramic samples significantly increased with increasing sintering temperature. The highest relative density, well-packed grains, and β-TCP stabilization by Mg at the Ca5 site of the FB-1250 structure were the dominant factors governing the highest mechanical properties. Although high density was observed in the SM-1200 sample, Vickers hardness of the SM-1200 sample is lower than the FB-1250 sample. This may be attributed to the partial decomposition of HAp into β-TCP, α-tricalcium phosphate (α-TCP), and Ca₁₀(PO₄)₆O phases. In addition, the increase of grain size was the main factor that governs the increasing compressive strength and Young's modulus instead of density and phase decomposition of the SM-ceramic samples.