Comparative analysis and antibacterial properties of thermally sintered apatites with varied processing conditions

Hydroxyapatite (HA) and biphasic hydroxyapatite/beta-tricalcium phosphate (biphasic HA/β-TCP) were synthesized using thermal sintering. The parameters- sintering temperature (600°C, 900°C, and 1200°C), biological source used (fish bone, egg shells, and fish scales), and soaking time (2, 6, and 10 hours) were permuted to study their effects on the properties of the resultant apatite. Morphological study revealed that the smallest (60 nm) spherical particle and the largest (470 nm) irregular shaped particle were obtained from the fish bone sample sintered at 600°C and at 1200°C respectively. FTIR and XRD results showed that as the sintering temperature is increased, the phase transformation from HA to β-TCP takes place. Only the final products from fishbone sample at 600°C are pure carbonated HA. The crystallinity of synthesized particles ranged from 79% to 98%. Soaking time has no effect on phase composition of the apatite but has significant effect on crystallite size; increase in soaking time increases crystallite size and particle shape becomes more spherical. Interestingly, the fish bone sample sintered at 900°C has higher crystallinity and crystallite size compared to the fish scale sample sintered at the same temperature. EDX confirmed that non-stoichiometric apatite with Ca/P ratio ranging from 1.47 to 1.91 can be obtained by varying the sintering conditions. The antibacterial test revealed that both calcium apatite obtained from fish bones and fish scales have inhibited bacterial growth; apatite from fish bone works faster than fish scales. The in vitro cytotoxicity test ensured that all the calcium apatite except for eggshell are non-cytotoxic. Thus, apatite with excellent microbial activity can be obtained by using fish wastes, and by tuning the sintering parameters, the apatite with desired types and properties can be synthesized for different biomedical applications.     

Study on the improvement of compressive strength and fracture toughness of calcium phosphate cement

Calcium phosphate cement (CPC) has superior properties, such as excellent bioactivity, biocompatibility, osteoconductivity and degradability, since its hydration product is hydroxyapatite (HA). As a novel cement material, CPC also shows injectable and self-setting properties. However, the compressive strength (CS) and fracture toughness of most CPCs are far lower than that of human weight-bearing bones, which largely limit their applications in the repairment of weight-bearing bones. To improve the CS and fracture toughness of CPC, several methods, including in-situ reinforcement by Ca4(PO4)2O (TTCP) ceramic particles, suitable nanofibers are introduced in this study. The maximal CS of CPC prepared with TTCP (average particle size of 22.3 ± 0.4 μm) reached to 98.4 MPa, which is close to the strength of human long bones. The enhanced CS of CPC was attributed to the in-situ reinforcing effect of residual TTCP particles. Tendon collagen slices and HA nanofibers were used to improve the fracture toughness of CPC. The flexural strength (FS) and the work of facture (WOF) of CPC were slightly increased by adding HA nanofibers but was significantly increased by the addition of tendon collagen slices. With 1.000 wt% tendon collagen slices, the FS and WOF of CPC were increased by 61.3% and 22.6 times, respectively.     

Cytocompatibility,bioactivity and mechanical strength of calcium phosphate cement reinforced with multi-walled carbon nanotubes and bovine serum albumin

This paper reports on the in vitro cytotoxicity, bioactivity behaviour and mechanical properties of novel injectable calcium phosphate cement filled with hydroxylated multi-walled carbon nanotubes and bovine serum albumin (CPC/MWCNT-OH/BSA). To predict the in vitro bioactivity of the calcium phosphate composites, we investigated apatite formation on CPC/MWCNT-OH/BSA composites after soaking in simulated body fluid (SBF) for up to 28 days. Compressive strength tests, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and cell culture experiments with human CCD-18Co fibroblasts cell lines were performed to evaluate the effect of SBF pre-treatment on the mechanical, structural and biological properties of the CPC/MWCNT-OH/BSA composites. Although apatite formation increased significantly with SBF immersion period, the results showed that all soaked CPC/MWCNT-OH/BSA composites exhibited up to 2.5 times lower compressive strength (13–20 MPa), which were however higher than values reported for the strength of trabecular bone (2–12 MPa). Cell culture experiments showed that low concentrations (6.25 and 12.5 μg/ml) of bio-mineralised CPC/MWCNT-OH/BSA composites led to cell proliferative rather than cytotoxic effects on fibroblasts, evidenced by high cell viabilities (104–113%). The novel CPC/MWCNT-OH/BSA composites presented in this study showed favourable cytocompatible and bioactive behaviour along with high compressive strength (13–32 MPa) and are therefore considered as an attractive bone filling material.     

Setting properties,mechanical strength and in vivo evaluation of calcium phosphate-based bone cements

Calcium phosphate cement (CPC) is a promising material for use in minimally invasive surgery for bone defect repair due to its similarity to the mineral phase of bone, biocompatibility, bioactivity, self-setting characteristics, low setting temperature, adequate stiffness and ease of shaping in complicated geometrics. In this study, we systematically investigate the influence of preparation variables on the final properties of CPCs. We determined the effects of CPC composition, accelerators, seed hydroxyapatite and reaction temperatures on the setting times and compressive strength of CPCs based on tetracalcium phosphate (TTCP), dicalcium phosphate dehydrate (DCPD), dicalcium phosphate anhydrous (DCPA), and α-tricalcium phosphate (α-TCP). The three types of CPCs (TTCP/DCPD, TTCP/DCPA, and TTCP/α-TCP-based bone cements) were prepared by varying the amounts of seed hydroxyapatite and citric acid used as a hardening accelerator. After 24 h of incubation, all three types of bone cements exhibited the characteristic peaks attributable to hydroxyapatite (HA) without characteristic peaks of unreacted raw materials. These results indicated that the bone cements were completely converted to HA. TTCP/DCPD-based bone cements showed faster setting times than TTCP/DCPA and TTCP/α-TCP-based bone cements. As citric acid concentrations in the liquid phase increased, the setting times of all three types of bone cements gradually decreased. However, the concentrations of seed HA in the cements were not related to significant changes in setting time. The compressive strengths of CPCs were significantly influenced by composition and reaction temperature. We also studied the effects of immersion time in physiological solution on the properties of the various CPCs. In the results of in vivo tests, subjects with bone defects implanted with CPCs exhibited more bone formation than control subjects that did not receive implantations of CPCs.     

In-vitro evaluation of thermoplastic starch/ beta-tricalcium phosphate nano-biocomposite in bone tissue engineering

Thermoplastic starch (TPS), as a natural based polymer, is known to have the capability to be used in biological applications due to its biocompatibility and biodegradability. In this study, mechanical properties of TPS are enhanced by incorporating bioactive β-tricalcium phosphate (β-TCP) particles for bone tissue engineering applications. Starch-based nanocomposites containing 3, 5, and 10 wt% of β-TCP nanoparticles (TT3, TT5, TT10) were made using a co-rotating twin-screw extruder. Dynamic light scattering (DLS) and X-ray diffraction (XRD) techniques were employed to analyze the nanocomposites. Moreover, degradability, swelling degree, and biomineralization in a simulated body fluid (SBF) were studied. To investigate the dispersion of β-TCP nanoparticles in the composite and biomineralization of the nanocomposites after incubation in SBF, scanning electron microscopy (SEM) and energy dispersive X-Ray analysis (EDX) were performed. Evaluation of mechanical properties of TPS and nanocomposites demonstrated that increase in β-TCP content enhanced mechanical properties. Besides, the bioactivity of these three nanocomposite materials was proven by nucleation of hydroxyapatite on the samples’ surface after incubation in simulated body fluid (SBF). Cytotoxicity test was done as well. Results of the current study have paved the way for the application of TPS/β-TCP composite as bone tissue engineering material.     

Chitosan graft copolymers‐HA/DBM biocomposites: Preparation,characterization, and in vitro evaluation

The combination of biopolymer with a bioactive component takes advantage of the osteoconductivity and osteoinductivity properties. The studies on composites containing hydroxyapatite (HA), demineralized bone matrix (DBM) fillers and chitosan biopolymer are still conducted. In the present study, the bioactive fillers were loaded onto p(HEMA‐MMA) grafted chitosan copolymer to produce a novel biocomposites having osteoinductive and osteoconductive properties. The produced composites were assessed by TGA, XRD, FTIR, and SEM techniques to prove the interaction between both matrices. In vitro behavior of these composites was performed in SBF to verify the formation of apatite layer onto their surfaces and its enhancement. The results confirmed the formation of thick apatite layer containing carbonate ions onto the surface of biocomposites especially these containing HA‐DBM mixture and pMMA having bone cement formation in their structure. These a novel biocomposites have unique bioactivity properties can be applied in bone implants and tissue engineering applications as scaffolds in future. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Control of Crystallinity of Hydrated Products in a Calcium Phosphate Cement

A novel calcium phosphate cement (CPC) was prepared by dry-mechanochemical rout in this work. With the different crystallinity, the CPC showed the different degradation ratio after setting. The degradation ratio of CPC was characterized by the calcium ion-dissolving ratio in deionized water after different soaking time. With the increment of crystallinity, the setting times of CPC were prolonged, and the different mechanical property of CPC were obtained. This novel CPC was supposed to match the new bone ingrowth in vivo and have the potential application in orthopedic surgery for filling non-load-bearing bone defects.     

Synthesis and characterization of hydroxyapatite/β-tricalcium phosphate nanocomposites using microwave irradiation

Microwave assisted synthesis method is a relatively new approach employed to decrease synthesis time and form a more homogenous structure in biphasic calcium phosphate bioceramics. In this study, nanocrystalline HA/β-TCP composites were prepared by microwave assisted synthesis method and, for comparison reason, by conventional wet chemical methods. The chemical and phase composition, morphology and particle size of powders were characterized by FTIR, XRD and SEM, respectively. The use of microwave irradiation resulted in improved crystallinity. The amount of hydroxyapatite phase in BCP ranged from 5% to 17%. The assessment of bioactivity was done by soaking of powder compacts in simulated body fluid (SBF). The decreasing pH of the solution in the presence of β-TCP indicated its biodegradable behavior. Rod-like hydroxyapatite particles were newly formed during the treatment in SBF for microwave assisted substrate synthesis. In contrast, globular particles precipitate under same conditions if BCP substrates were synthesized using conventional wet chemical methods.     

磷酸钙骨水泥中羟基磷灰石在碳纳米管上的吸附生长

为提高磷酸钙骨水泥(calcium phosphate bone cement,CPC)的力学性能,扩大其临床应用,制备了碳纳米管(carbon nanotubes,CNTs)增强的CPC复合材料.在复合材料微观结构观察中发现:CNTs在骨水泥固化体中以一种新颖的形式存在,即CNTs在基体中已失去本来形貌,骨水泥水化产物羟基磷灰石(hydroxyapatite,HA)在其表面生长包覆,最终形成了HA/CNTs复合增强体.对该复合增强体的形成过程进行了研究,并提出了HA在CNTs上吸附生长的模型.     

Evaluation of the electrical and dielectric behavior of the apatite layer formed on the surface of hydroxyapatite/hardystonite/copper oxide hybrid nanocomposites for bone repair applications

The work aimed to prepare nanocomposites with good electrical and mechanical properties and acceptable bioactivity behavior to be suitable for bone repair applications. In this context, hydroxyapatite (HA) and hardystonite (HT) were prepared by mechanochemical synthesis method. Subsequently, nanocomposites of different contents of HA, HT and copper oxide (CuO) were prepared, sintered and characterized by X-ray diffraction (XRD) technique and scanning electron microscopy (SEM). In addition, bioactivity was evaluated in vitro after treatment in simulated body fluid (SBF) and HA layer formation was confirmed by SEM in conjunction with energy dispersive X-ray analysis (EDX). The electrical and dielectric properties were measured before and after treatment in SBF solution. Elastic and physical properties were also measured. The results clarified that the sintering temperature used along with the successive increase of HT and CuO contents achieved good densification behavior and better mechanical properties, especially compressive strength, to avoid the stress-shielded bone effect. Also, HT and CuO positively enhanced the electrical conductivity and reduced the dielectric properties of nanocomposites prepared. The latter results have a great role in promoting fracture healing. Based on the above results, the prepared nanocomposites are promising for potential use in bone repair applications.     

钙-磷系自固化材料改性研究进展

由创伤、肿瘤和感染等原因引起的骨缺损通常面积较大,超过了骨自愈范围而不能自修复。因此,需要使用骨水泥对面积较大的骨缺损部位进行填充修复。磷酸钙水泥(calcium phosphate cement, CPC)是目前临床常用的一种骨水泥,可任意塑形,具有良好生物活性和生物相容性,近几十年来得到国内外学者的广泛研究。然而,从临床实践经验来看,CPC的应用范围有限,仍需要对其进行性能改进。本文主要分为两部分:在理化性能部分总结了CPC在力学强度、可注射性、抗溃散性和放射不透明性等四方面的改性方法;在生物学性能方面讨论了CPC成骨活性、生物可降解性和载药性方面的改性研究。     

The preparation and characterization of HA/β-TCP biphasic ceramics from fish bones

The aim of this research is to observe the physicochemical characterization and evaluate the biocompatibility of the HA/β-TCP biphasic calcium phosphate ceramics (BCP) produced from fish bones. In addition, the mechanism of the formation of BCP after calcination of fish bones was discussed. Three kinds of fish bones (Salmo salar, Anoplopoma fimbria and Sardine) were prepared and calcined for one hour at different temperatures ranging from 600 °C to 1100 °C in a muffle furnace. The calcined bones were analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (GTA), inductively coupled plasma optical atom emissions spectroscopy (ICP-OES), X-ray fluorescence (XRF) and scanning electron microscopy (SEM). The in vitro cytotoxicity assessment was used to evaluate the biocompatibility of the biphasic ceramics. BCP materials were produced from all kinds of fish bones by calcination above 700 °C, the carbonated hydroxyapatite and multiple trace element were also found in the calcined bones. With the increase of temperature, the ratio of HA/β-TCP varied and the major organic components were progressively removed. The carbonated hydroxyapatite disappeared when temperature rises above 900 °C. Rising temperature also caused crystal growth that eventually gave rise to the increase of the BCP grain size and influenced the mesoporous structure. The BCP materials were confirmed to have no obvious cytotoxicity to mesenchymal stem cells (MSC) in the in vitro cytotoxicity assessment. Calcium-deficient hydroxyapatite(CDHA) may make up the major inorganic constituent of fish bones that could decompose to HA and β-TCP when calcined above 700 °C. 800–900 °C is considered to be the optimal temperature to fabricate BCP materials which contain more β-TCP, carbonated hydroxyapatite and retain distinct mesoporous structure while has good biocompatibility. With the unique composition and structure, these three kinds of fish-bone-derived BCP materials can be further applied to fabricate bioceramic scaffolds for biomedical applications.     

Polymeric calcium phosphate cements incorporated with poly‐γ‐glutamic acid: Comparative study of poly‐γ‐glutamic acid and citric acid

Polymeric calcium phosphate cements (PCPC) derived from biodegradable poly‐γ‐glutamic acid (γ‐PGA) were prepared in an attempt to improve the mechanical strength of calcium phosphate cement (CPC). The characteristics of the PCPCs were compared with those of cement incorporated with citric acid. The diametral tensile and compressive strengths of the CPC incorporated with γ‐PGA were significantly higher than that of cement incorporated with citric acid at equivalent concentrations (P < 0.05). The maximal diametral tensile and compressive strengths of the CPC incubated for 1 week in physiological saline solution were approximately 18.0 and 50.0 MPa, respectively. However, the initial setting time of the PCPC was slower than that of CPC incorporated with citric acid. The formation of ionic complexes between calcium ions and γ‐PGA was observed using FTIR spectroscopy. Hydroxyapatite (HA) formation was retarded by γ‐PGA incorporation according to scanning electronic microscopy (SEM) and powder X‐ray diffraction (XRD) observations. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Investigation of mechanical behavior of CPC/bone specimens by finite element analysis

Calcium phosphate cement (CPC), as an important injectable biomaterial, is extensively used for bone repair in clinical application. If mechanical properties of CPC match well with that of bone tissue, it can create an appropriate mechanical environment for bone repair. In our study, the objective was to investigate the responses of bone tissue to CPC in different series of elastic modulus combinations. Finite element analysis (FEA) was applied to calculate the stress/strain on CPC-bone specimens and to further forecast the potential risky area. The predicted results indicated that CPC materials and bone tissue had different stress distribution patterns under the same loading condition. For CPC material, the Von Mises Stress peak occurred in the bone–cement joint area; while for bone tissue, the risky area was located at the bridge area among trabecular bones. The porous and loose structure of cancellous bone induced a greater Von Mises Stress in bone tissue. Quantitative analysis indicated that stress/strain distribution was directly correlated with the elastic modulus of material. When Young's modulus of bone and CPC was 1 GPa and 6.10 GPa respectively, the optimal stress matching between bone and CPC was achieved. In sum, this work confirmed that FE modeling was the ideal method for predicting fracture behavior of bone–CPC specimen both qualitatively and quantitatively.     

Bioactivity and Antibacterial Behaviors of Nanostructured Lithium-Doped Hydroxyapatite for Bone Scaffold Application

The material for bone scaffold replacement should be biocompatible and antibacterial to prevent scaffold-associated infection. We biofunctionalized the hydroxyapatite (HA) properties by doping it with lithium (Li). The HA and 4 Li-doped HA (0.5, 1.0, 2.0, 4.0 wt.%) samples were investigated to find the most suitable Li content for both aspects. The synthesized nanoparticles, by the mechanical alloying method, were cold-pressed uniaxially and then sintered for 2 h at 1250 °C. Characterization using field-emission scanning electron microscopy (FE-SEM) revealed particle sizes in the range of 60 to 120 nm. The XRD analysis proved the formation of HA and Li-doped HA nanoparticles with crystal sizes ranging from 59 to 89 nm. The bioactivity of samples was investigated in simulated body fluid (SBF), and the growth of apatite formed on surfaces was evaluated using SEM and EDS. Cellular behavior was estimated by MG63 osteoblast-like cells. The results of apatite growth and cell analysis showed that 1.0 wt.% Li doping was optimal to maximize the bioactivity of HA. Antibacterial characteristics against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were performed by colony-forming unit (CFU) tests. The results showed that Li in the structure of HA increases its antibacterial properties. HA biofunctionalized by Li doping can be considered a suitable option for the fabrication of bone scaffolds due to its antibacterial and unique bioactivity properties.     

Phosphate content affects structure and bioactivity of sol-gel silicate bioactive glasses

Bioactive glasses can heal bone defects and bond with bone through formation of hydroxyl carbonate apatite (HCA) surface layer. Sol-gel derived bioactive glasses are thought to have potential for improving bone regeneration rates over melt-derived compositions. The 58S sol-gel composition (60 mol% SiO₂, 36 mol% CaO, and 4 mol% P₂O₅) has appeared in commercial products. Here, hydroxyapatite (HA) was found to form within the 58S glass during sol-gel synthesis after thermal stabilization. The preformed HA may lead to rapid release of calcium orthophosphate, or nanocrystals of HA, on exposure to body fluid, rather than the release of separate the calcium and phosphate species. Increasing the P₂O₅ to CaO ratio in the glass composition reduced preformed HA formation, as observed by XRD and solid-state NMR. Instead, above 12 mol% phosphate, a phosphate glass network (polyphosphate) formed, creating co-networks of phosphate and silica. Nanopore diameter of the glass and rate of HCA layer formation in simulated body fluid (SBF) decreased when the phosphate content increased.     

The fabrication and characterization of bioactive Akermanite/Octacalcium phosphate glass-ceramic scaffolds produced via PDC method

In the present study, a bioactive silicate-phosphate glass-ceramic scaffold was fabricated via the polymer-derived ceramics (PDC) method. K₂HPO₄ phosphate salt was used as the P₂O₅ precursor in this method. The effect of K₂HPO₄ wt% and heat treatment temperatures (900–1100 °C) was evaluated. It was observed that although increasing the wt% of K₂HPO₄ led to the formation of scaffolds with higher densities and strengths, it could also increase the formation of the calcium phase, which could result in improper release behavior of scaffolds. On the other hand, higher heat treatment temperatures enhanced the strength of the scaffolds but eliminated the bioactive octacalcium phosphate (OCP) phase. X-ray diffraction (XRD) analysis showed that the dissolution of the OCP phase in simulated body fluid (SBF) resulted in precipitation of hydroxyapatite (HA) on the scaffold surface which enhanced the bioactivity. Furthermore, based on microstructural studies by Scanning Electron Microscopy (SEM), the fabricated scaffold possessed a wide range of pore sizes, appropriate for osteointegration and bone formation. The optimum wt% of phosphate salt was less than 6 wt% and the optimum heat treatment temperature was 1000 °C. After the optimization of compositions and processing, Alamar Blue Assay was used to evaluate HOb cell cultures, showing a continuous proliferation for the optimized samples.     

Two-step modification process to improve mechanical properties and bioactivity of hydroxyfluorapatite scaffolds

Porous ceramic scaffolds are synthetic implants, which support cell migration and establish sufficient extracellular matrix (ECM) and cell-cell interactions to heal bone defects. Hydroxyapatite (HA) scaffolds is one of the most suitable synthetic scaffolds for hard tissue replacement due to their bioactivity, biocompatibility and biomimetic features. However, the major disadvantages of HA is poor mechanical properties as well as low degradability rate and apatite formation ability. In this study, we developed a new method to improve the bioactivity, biodegradability and mechanical properties of natural hydroxyfluorapatite (HFA) by applying two-step coating process including ceramic and polymer coats. The structure, morphology and bioactivity potential of the modified and unmodified nanocomposite scaffolds were evaluated using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and energy dispersive spectroscopy (EDS). The scaffold with optimized mechanical properties was HFA-30?wt%HT (HT stands for hardystonite) with a total porosity and pore size of 89?±?1 and 900–1000?µm, respectively. The compressive modulus and strength of HFA (porosity ~ 93?±?1) were improved from 108.81?±?11.12–251.45?±?12.2?MPa and 0.46?±?0.1–1.7?±?0.3?MPa in HFA-30?wt%HT sample, respectively. After applying poly(ε-caprolactone fumarate) (PCLF) polymer coating, the compressive strength and modules increased to 2.8?±?0.15 and 426.1?±?15.14?MPa, respectively. The apatite formation ability of scaffolds was investigated using simulated body fluid (SBF). The results showed that applying the hardystonite coating improve the apatite formation ability; however, the release of ions increased the pH. Whereas, modified scaffolds with PCLF could control the release of ions and improve the apatite formation ability as well.     

In Situ Crosslinking of Highly Porous Chitosan Scaffolds for Bone Regeneration: Production Parameters and In Vitro Characterization

Various methods of chitosan scaffold production are reported in the literature so far. Here, in situ crosslinking with glutaraldehyde is reported for the first time. It combines pore formation and chitosan crosslinking in a single step. This combination allows incorporation of fragile molecules into 3D porous chitosan scaffolds produced by simple and gentle lyophilization. In this study, parameters of in situ crosslinking of porous chitosan scaffold formation as well as their effect on degradation and bioactivity of the scaffolds are examined. The scaffolds are characterized in the context of their prospective application as bone substitute material. The addition of calcium phosphate phases (hydroxyapatite, brushite) to the macroporous chitosan scaffolds allows manipulation of the bioactivity that is investigated by incubation in simulated body fluid (SBF). The bioactivity is significantly influenced by the modus of changing the fluid (static, daily‐, and twice‐a‐week change). Scaffolds are morphologically characterized by means of scanning electron microscopy, and the mechanical stability is tested after incubation in SBF and phosphate‐buffered saline.     

Synthesis and dissolution behavior of nanosized silicon and magnesium co-doped fluorapatite obtained by high energy ball milling

Nanosized hydroxyapatite (HA) powders exhibit a greater surface area than coarser crystals and are expected to show an improved bioactivity. In addition, properties of HA can be tailored over a wide range by incorporating different ions into HA lattice. The aim of this study was to prepare and characterize silicon and magnesium co-doped fluorapatite (Si–Mg–FA) with a chemical composition of Ca_9.5Mg_0.5 (PO₄)_5.5(SiO₄)_0.5F₂ by the high-energy ball milling method. Characterization techniques such as X-ray diffraction analysis (XRD), Fourier transformed infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM) were utilized to investigate the structural properties of the obtained powders. Dissolution behavior was evaluated in simulated body fluid (SBF) and physiological normal saline solution at 37 °C for up to 28 days. The results of XRD and FTIR showed that nanocrystalline single-phase Si–Mg–FA powders were synthesized after 12 h of milling. In addition, incorporation of magnesium and silicon into fluorapatite lattice decreased the crystallite size from 53 nm to 40 nm and increased the lattice strain from 0.220% to 0.296%. Dissolution studies revealed that Si–Mg–FA in comparison to fluorapatite (FA), releases more Ca, P and Mg ions into SBF during immersion. 175 ppm Ca, 33.5 ppm P and 48 ppm Mg were detected in the SBF containing Si–Mg–FA after 7days of immersion, while for FA, it was 75 ppm Ca, 21.5 ppm P and 29 ppm Mg. Release of these ions could improve the bioactivity of the obtained nanopowder. It could be concluded that the prepared nanopowders have structural properties such as crystallite size (~40 nm), crystallinity degree (~40%) and chemical composition similar to biological apatite. Therefore, prepared Si–Mg–FA nanopowders are expected to be appropriate candidates for bone substitution materials and also as a phase in polymer or ceramic-based composites for bone regeneration in tissue engineering applications.