Synthesis Of Hydroxyapatite Nanoparticles Research Articles

Controlling pore size during the synthesis of hydroxyapatite nanoparticles using CTAB by the sol–gel hydrothermal method and their biological activities

Abstract Nanorod and nanosphere hydroxyapatite (HAP) particles were synthesized by the sol–gel hydrothermal method. The size of the synthesized HAP nanoparticles was controlled using cetyltrimethylammonium bromide (CTAB) as a templating agent with molar concentrations (HAP + 0.01 M CTAB, HAP + 0.03 M CTAB, and HAP + 0.1 M CTAB). The purity, size, shape, and elemental composition of HAP were determined using powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy, which enabled us to determine the nanostructure formation. Further, Brunauer–Emmett–Teller analysis of the samples proves the size of the pores to be 7–10 nm. Thus, by altering the concentration of CTAB, HAP nanorods were induced along the c-axis. The zeta potential values of −34.7 and −28.7 mV confirmed the stability of pure HAP and HAP + 0.01 M CTAB. Further, the biological activities of the HAP nanoparticles were determined. In the anti-microbial activity test, an increase in the inhibition with an increase in the concentration of pure HAP to 0.1 M CTAB + HAP was observed against S. aureus, S. pyrogens, B. subtilis, E. aerogens, K. pneumoniae, and P. vulgaris. About 76% of antioxidant activity was obtained from the experiments. The drug-release behavior of doxorubicin-loaded pure HAP and CTAB-coated HAP also indicates that the % of drug delivery depends on the pores, which further depends on the CTAB concentration. The cytotoxic assay also revealed potential inhibitory effects against human cancer cell lines (MCF-7), with 65% cell viability recorded at a concentration of 500 μg/ml. These findings indicate that the pore size and shape of HAP play significant roles in their biological activities.

Aspartic Acid Binding on Hydroxyapatite Nanoparticles with Varying Morphologies Investigated by Solid-State NMR Spectroscopy and Molecular Dynamics Simulation.

Hydroxyapatite (HAP) exhibits a highly oriented hierarchical structure in biological hard tissues. The formation and selective crystalline orientation of HAP is a process that involves functional biomineralization proteins abundant in acidic residues. To obtain insights into the process of HAP mineralization and acidic residue binding, synthesized HAP with specific lattice planes including (001), (100), and (011) are structurally characterized following the adsorption of aspartic acid (Asp). The adsorption affinity of Asp on HAP surfaces is evaluated quantitatively and demonstrates a high dependency on the HAP morphological form. Among the synthesized HAP nanoparticles (NPs), Asp exhibits the strongest adsorption affinity to short HAP nanorods, which are composed of (100) and (011) lattice planes, followed by nanosheets with a preferential expression of the (001) facet, to which Asp displays a similar but slightly lower binding affinity. HAP nanowires, with the (100) lattice plane preferentially developed, show significantly lower affinity to Asp and evidence of multilayer adsorption compared to the previous two types of HAP NPs. A combination of solid-state NMR (SSNMR) techniques including 13C and 15N CP-MAS, relaxation measurements and 13C-31P Rotational Echo DOuble Resonance (REDOR) is utilized to characterize the molecular structure and dynamics of Asp-HAP bionano interfaces with 13C- and 15N-enriched Asp. REDOR is used to determine 13C-31P internuclear distances, providing insight into the Asp binding geometry where stronger 13C-31P dipolar couplings correlate with binding affinity determined from Langmuir isotherms. The carboxyl sites are identified as the primary binding groups, facilitated by their interaction with surface calcium sites. The Asp chelation conformations revealed by SSNMR are further refined with molecular dynamics (MD) simulation where specific models strongly agree between the SSNMR and MD models for the various surfaces.

Synthesis of Hydroxyapatite Nanoparticles Using Eggshells and Two Different Phosphate Sources

Hydroxyapatite, the primary bone substitute, has gained increased interest of researchers. The primary purpose of this study was to synthesize hydroxyapatite nanoparticles through the utilization of eggshell waste and two distinct phosphate sources ((NH4)2HPO4 and Na3PO4.12H2O). The chemical precipitation approach was chosen for this study, then the final products were named HAP-1 and HAP-2. Following this, the synthesized particles were investigated using XRD, FTIR, and SEM methods. The crystallite size of the synthesized materials was also determined by employing the Debye-Scherrer equation. The synthesis of the HAP granules was confirmed through XRD analysis, and the crystallite sizes of HAP-1 and HAP-2 were calculated to be 37.79 nm and 28.7 nm, respectively. The SEM results also indicates that the powders had a spherical-like morphology, but were highly agglomerated due to their nanoscale dimensions.

Filter cake-derived calcium carbonate polymorphs from sugar refinery for hydroxyapatite production as a sustainable material for biomedical application

In this study, sugarcane filter cake (SFC) was refined to produce calcium carbonate (CaCO3) via the calcination method under a controlled environment. The obtained CaCO3 and orthophosphoric acid were used as calcium and phosphorus precursors respectively to synthesize hydroxyapatite (HA) through the wet precipitation method. Morphological investigation showed different morphologies of CaCO3 particles. The scanning electron microscopy (SEM) image showed high agglomeration of CaCO3 particles and the synthesized HA nanoparticles. Particle size analysis of CaCO3 and the HA nanoparticles revealed an average size of 0.9 μm and a crystallite size of 24.33 nm, respectively. X-ray diffraction (XRD) and Wide-angle x-ray scattering (WAXS) analysis confirmed the phase of calcium carbonate coexisting with both calcium hydroxide and calcium oxide, and a single phase of carbonated HA. The calcium to phosphorus (Ca/P) ratio of HA derived from calcinated filter cake was 1.66, which is close to the stoichiometric value of 1.67. The HA nanoparticles were biocompatible, with no evidence of toxicity to MC3T3-E1 cells. This study has demonstrated the feasibility of utilizing sugarcane filter cake as a sustainable raw material for CaCO3 and HA production. The as prepared HA is similar to biological apatite found in mammals and is potentially useful for hard tissue repair and other biomedical applications.

Unveiling the Anti-Biofilm Property of Hydroxyapatite on Pseudomonas aeruginosa: Synthesis and Strategy.

Biofilm-related nosocomial infections may cause a wide range of life-threatening infections. In this regard, Pseudomonas aeruginosa biofilm is becoming a serious health burden due to its capability to develop resistance to natural and synthetic drugs. The utilization of nanoparticles that inhibit biofilm formation is one of the major strategies to control infections caused by biofilm-forming pathogens. Hydroxyapatite (HA) is a synthetic ceramic material having properties similar to natural bones. Herein, a co-precipitation method followed by microwave treatment was used to synthesize HA nanoparticles (HANPs). The resulting HANPs were characterized using X-ray diffraction and transmission electron microscopy. Then, their antibiofilm properties against P. aeruginosa ATCC 10145 were examined in vitro. The needle-shaped HANPs were 30 and 90 nm long in width and length, respectively. The synthesized HANPs inhibited the biofilm formation of P. aeruginosa ATCC 10145 in a concentration-dependent manner, which was validated by light and confocal laser scanning microscopy. Hence, this study demonstrated that HANPs could be used to control the biofilm-related infections of P. aeruginosa.

Structural, Spectroscopic, and Biological Characterization of Novel Rubidium(I) and Europium(III) Co-Doped Nano-Hydroxyapatite Materials and Their Potential Use in Regenerative Medicine.

This research investigates hydrothermally synthesized hydroxyapatite nanoparticles doped with rubidium(I) and europium(III) ions. Investigation focused on establishing the influence of co-doped Eu3+ and Rb+ ions on hydroxyapatite lattice. Therefore, structural, and morphological properties were characterized via using X-ray powder diffraction (XRPD), infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM), as well as transmission electron microscopy (TEM) techniques. Furthermore, this investigation evaluates the impact of various Rb+ ion doping concentrations on the distinct red emission of co-doped Eu3+ ions. Hence, luminescence properties of the obtained materials were evaluated by measuring emission excitation, emission spectra, and luminescence decays. As established by numerous studies, synthetic hydroxyapatite has excellent application in biomedical field, as it is fully biocompatible. Its biocompatible makes it highly useful in the biomedical field as a bone fracture filler or hydroxyapatite coated dental implant. By the incorporation of Eu3+ ions and Rb+ ions we established the impact these co-doped ions have on the biocompatibility of hydroxyapatite powders. Therefore, biocompatibility toward a ram's red blood cells was evaluated to exclude potential cytotoxic features of the synthesized compounds. Additionally, experimental in vitro bioactive properties of hydroxyapatite nanoparticles doped with Rb+ and Eu3+ ions were established using a mouse osteoblast model. These properties are discussed in detail as they contribute to a novel method in regenerative medicine.

The effect of hydroxyapatite nanoparticles on wettability and brine-oil interfacial tension as enhance oil recovery mechanisms

A novel concept of utilizing nanoparticles (NPs) to boost oil recovery and reduce entrapped oil in hydrocarbon reservoirs is being explored. The use of nanofluids (NFs) flooding to change wettability and reduce interfacial tension (IFT) between oil and water has been shown to be highly effective in experiments. Preparation and modification methods influence the performance of NPs. The application of hydroxyapatite NPs (HAP) in EOR has yet to be investigated. HAP was synthesized in this study using the co-precipitation method and in-situ surface functionalization with Sodium Dodecyl Sulphate SDS to visualize it effect on IFT reduction and wettability alteration under different salinity and temperature settings. To confirm the synthesis of HAP, zeta potential (ZP), Fourier transform infrared spectroscopy (FTIR), Particle size analysis (PSA), Transmission electron microscopy (TEM), and Energy dispersive X–ray (EDX) spectra were used respectively. According to the results, HAP was produced, and the particles were finely distributed and stable in aqueous solution. When the pH was altered from 1 to 13, the particles' surface charge rose from -5mV to −27mV, showing long-term stability in EOR processes. At salinity range from 5000 ppm to 30,000 ppm, and under temperature range from 25ᵒC to 80ᵒC, the HAP NFs changed the wettability of sandstone core from oil–wet at 111.7° to water–wet at 9.0°. In addition, at 0.1 wt% HAP concentration, the IFT was lowered to 3 mN/m. As a result, the HAP NF proved very effective in reducing IFT and altering wettability under both low and high salinity environments, and it is thus suggested for EOR operations.

Synthesis of hydroxyapatite nanoparticles using Acacia falcata leaf extract and study of their anti-cancerous activity against cancerous mammalian cell lines

This study deals with the synthesis of hydroxyapatite nanoparticles (HAPnps) mediated by Acacia falcata leaf extract. Aggregates of needle-shaped crystalline nanostructures were confirmed by FE-SEM and TEM analysis. Well-defined rings in the SAED patterns corroborated the polycrystalline nature of the HAPnps. Individual elements present in the HAPnps were attested by the specific signals for Ca, P, and O in the EDS and XPS analyses. The distinct peaks observed in the XRD spectrum matched well with the HAP hexagonal patterns with a mean crystallite size of 55.04 nm. The FTIR study unveiled the coating of the nanoparticles with the biomolecules from Acacia falcata leaves. The suspension HAPnps exhibited polydispersity (0.446) and remarkable stability (zeta potential: − 31.9 mV) as evident from DLS studies. The pore diameter was 25.7 nm as obtained from BET analysis, suggesting their mesoporous nature. The HAPnps showed the cytotoxic effect on A549 lung and MDA-MB231 breast carcinoma cell lines, with an IC50 value of 55 μg/mL. The distortion of the cell membrane and cell morphology, along with the chromatin condensation and cell necrosis on treatment with HAPnps were detected under fluorescence microscopy post acridine orange/ethidium bromide dye staining. This study reports the anti-cancerous potential of non-drug-loaded plant-mediated HAPnps. Therefore, the HAPnps obtained in this investigation could play a vital role in the biomedical field of cancer therapy.

Hydroxyapatite nanoparticles in situ grown on carbon nanotube as a reinforcement for poly (ε-caprolactone) bone scaffold

The incorporation of carbon nanotubes (CNT) and hydroxyapatite (HA) into biopolymer as bone scaffold is expected to combine the excellent mechanical properties of CNT and bioactivity of HA. However, the dispersion of CNT and HA in biopolymer is a challenge. In this paper, under the condition of hydrothermal reaction, HA nanoparticles were in situ synthesized on the surface of carboxyl multi-walled CNT to prevent their aggregation in poly (ε-caprolactone) (PCL) scaffold prepared by selective laser sintering (SLS). The mechanism of in situ synthesis of HA nanoparticles was that the carboxyl functional groups of cCNT acted as anchor sites for Ca2+ deposition, and then Ca2+ attracted HPO42− via electrovalent bonding to in situ nucleation and synthesis of HA nanocrystals. The results demonstrated that HA nanoparticles ranged from about 10 to 30 nm in diameter and 40–80 nm in length were homogeneously generated on the surface of cCNT. Compared with the pure PCL scaffold, the scaffold with contenting of 12% cCNT-HA was increased by 86.6% and 31.9% in tensile and compressive strength, respectively. The strengthening mechanisms could be explained from the bridging and pulling out of the cCNT-HA. Meanwhile, the mineralization experiment results demonstrated that the Ca/P ratio of apatite layer formed on the surface of the PCL/12% cCNT-HA scaffold was 1.66, which was close to that of human bone tissue, indicating the scaffold possessed good bioactivity for inducing the formation of apatite mineralization. Besides, the scaffolds displayed good cytocompatibility for cell attachment, growth and proliferation.

Performance of innovative nanomaterials for bone remains consolidation and effect on 14C dating and on palaeogenetic analysis

An innovative protocol for the consolidation of ancient bone remains based on the use of nanometric HydroxyAPatite (HAP) was set up and tested through a multidisciplinary approach. A new protocol for the synthesis of HAP nanoparticles was developed, and the composition of the obtained nanomaterial was investigated through Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD); sizes, shape and morphology of the synthesized particles were studied by Scanning Electron Microscopy (SEM). The consolidation performance was evaluated by testing the new nanomaterial on degraded ancient bone findings. An increase of the mineral density and of the micro-hardness of the bone were observed. The new consolidation method was also tested to assess possible effects on the palaeogenetic analysis and radiocarbon dating on the treated bones. The consolidation treatment does not introduce any contaminations that could affect radiocarbon dating and has no general detrimental impact on the genetic characterization of the skeletal remains. This consolidation procedure represents a more compatible conservation tool with respect to traditional procedures: it has been shown that the treatment is effective, easily-applicable and compatible with post-consolidation analysis.

Nanostructural control of transparent hydroxyapatite nanoparticle films using a citric acid coordination technique.

Hydroxyapatite (HA), as the main mineral component in hard tissues, has good biocompatibility. In particular, HA films are widely used as bioactive coatings for artificial bones and dental implants in biomedical fields. However, it is currently difficult to prepare a nanostructure-controlled HA film by a wet process for further applications. Herein, we report the synthesis of HA nanoparticles coordinated by citric acid (Cit/HA) based on the interactions between carboxylate and calcium ions to control the sizes and shapes of the hybrid nanoparticles, to improve their dispersibility in water and to eventually form uniform transparent films with nanospaces, and investigated the film formation mechanism. As compared with the well-known rod-like HA nanoparticles (size: 48 × 15 nm2), we successfully synthesized spherical and negatively charged Cit/HA nanoparticles (size: 25 × 23 nm2) to achieve highly transparent Cit/HA films using the spin-coating technique. The Cit/HA films had uniform and crack-free appearance. About the nanostructures, we found that the Cit/HA film surfaces had meso-scaled nanospaces with a diameter of 4.2 nm based on the regular arrangement of spherical nanoparticles, instead of the HA film with a nanospace diameter of 24.5 nm formed by non-uniform accumulation. Therefore, we successfully achieved the control of the nanospace sizes of the films with the nanoparticle arrangement and realized transparent nanoparticle film formation in a very simple way, which will provide more convenient bioceramic films for biomedical applications.

Synthesis of Hydroxyapatite Nanoparticles from Phosphorus Recovered from Animal Wastes

Phosphorus (P) loss from agricultural soils and its adverse impact on the ecosystem have resulted in renewed calls on resource recovery. In this study, we tested five methods of purification of P extracted from common animal wastes (chicken litter and dairy cow, horse, sheep, and swine manures) to fabricate hydroxyapatite nanoparticles (HANPs), a potential nanofertilizer. Crystallization of HANPs from P extracts from swine manure and chicken litter was achieved with no purification of the extract but the yield and purity were compromised. All synthesized HANPs from partially purified P were carbonated apatite in which columnar hydroxyls are replaced by carbonate, which is ideal for enhancing the solubility. The TEM and XRD analyses were carried out to verify the nanodimension and phase crystallinity of HANPs. The concentration of heavy metals in HANPs decreased by 3–5 log orders compared to waste during purification and crystallization. Overall, these results suggest that the recovery and recycling of P from animal wastes and synthesis of pure HANPs are feasible and together contribute to the efforts on recycling a nonrenewable resource as well as protecting the environment.

Mechanism of Inhibition of Hydroxyapatite Nanoparticles on Cancer Cells and Recent Advances in the Field

Background: Calcium phosphates are chemically similar to bone minerals. The biocompatibility, bioactivity, and high similarity of these substances to body organs such as bone have made them a good choice for disease diagnosis and treatment. Here, the main use of calcium phosphates is diagnosis and treatment of cancers. Hydroxyapatite is a bioactive material with a high affinity for DNA and protein. Recently, hydroxyapatite nanoparticles exhibit different properties than those of bulk hydroxyapatite in chemistry and biology. In general, the anticancer effects of hydroxyapatite nanoparticles have been attributed to high amounts of endocytosis in cancer cells and inhibits of protein synthesis in cells. Methods: Herein, we evaluated the structure, properties, and methods of synthesis of hydroxyapatite nanoparticles. Moreover, the mechanism of inhibition of hydroxyapatite nanoparticles on cancer cells and recent advances in this field have been examined. Conclusion: Hydroxyapatite nanoparticles had the ability to eliminate the development of cancer cells in vitro and in vivo. In the live tissue environment, injection of hydroxyapatite nanoparticles at the tumor’s surrounding area had a significant decrease in tumor size (about 50%).

Effect of pH on the In Vitro Biocompatibility of Surfactant-Assisted Synthesis and Hydrothermal Precipitation of Rod-Shaped Nano-Hydroxyapatite.

Given their wide range of biomedical applications, hydroxyapatite (HA) nanoparticles are an attractive material widely used in many fields. Therefore, a simple, inexpensive, and stable process for the synthesis of HA nanoparticles is necessary to meet current needs. Herein, we studied HA synthesis assisted by four surfactants, namely cation, anion, non-ionic, and zwitterion templates, to verify the synthesis phase, aspect ratio, morphology, and biocompatibility under different environments (i.e., pH 4 and 9) before and after calcination. Results showed that before calcination, the surfactant-free groups could not produce HA but showed an abundant dicalcium phosphate anhydrous (DCPA) phase at pH 4. Except for the anionic group containing a small amount of DCPA, all surfactant-assistant groups presented single-phase HA in acidic and alkaline environments. The diameter of HA synthesized at pH 4 was significantly larger than that of HA synthesized at pH 9, and the effect of aspect ratio changes after calcination was more significant than that before calcination. The uncalcined rod-shaped HA synthesized with a non-ionic template at pH 4 demonstrated excellent cell viability, whereas anionic, cationic, and non-ionic surfactants exhibited biocompatibility only after calcination. At pH 9, non-ionic and uncalcined zwitterion-assisted rod-shaped HA showed excellent biocompatibility. In conclusion, the uncalcined HA rod-shaped nanoparticles synthesized from the non-ionic template at pH 4 and 9 and the zwitterion template at pH 9, as well as all surfactant-assisted HA after calcination, had no cytotoxicity. These tailor-made non-toxic HA types can meet the different requirements of apatite composite materials in biomedical applications.

Hydroxyapatite integrated with cellulose acetate/polyetherimide composite membrane for biomedical applications

AbstractIn this study, we describe the experience of a simple, cost‐efficient preparation and characterization of hydroxyapatite (HA) nanomaterial incorporated cellulose acetate/polyetherimide membrane for adsorption and biomedical applications. A simple chemical precipitation technique has been used for the synthesis of HA nanoparticles. The membrane was then developed by incorporating nanoparticles into different compositions of cellulose acetate and polyetherimide by using a phase inversion technique. Fourier transmission infrared spectroscopy, X‐ray diffraction spectroscopy, high‐resolution transmission electron microscope, field emission scanning electron microscope, and energy dispersive X‐ray spectroscopy were used to characterize the structural analysis and morphology of the nanoparticles and polymer membrane. Thermo gravimetric analysis was used to describe thermal characteristics. The contact angle value and wettability test were used to determine the hydrophilicity of the polymer membrane. The images from the scanning electron microscope analysis indicate that the addition of hydroxyapatite nanoparticles causes significant morphological changes in the membrane's surface and cross section. When compared with a control membrane, the presence of inorganic nanoparticles elucidated the impact on thermal and hydrophilic properties. The CA/PEI/HA membrane can be used as an adsorbent material in dye adsorption experiments with model dyes such as Malachite green, Methylene blue as cationic dyes, and Eriochrome black T, Congo red as anionic dyes. In addition, the biocompatibility of the CA/PEI/HA membrane was tested using cell cytotoxicity against THP‐1 human monocytic leukemia cells.

Synthesis of silver/hydroxyapatite/tryptophan nanocomposite particles by biological method

The inorganic calcium phosphate compound hydroxyapatite (HAP) is widely used in bone and teeth proxy applications in the biomedical field. The efficacy of this material depends on size and absolutely morphology. Synthesis of hydroxyapatite nanoparticles with appreciable size and morphology is considered as a significant technology. However, post-surgery bacterial infections were also accounted that could be a crucial and challengeable for a good biomaterial. To compensate, all issues, synthesis of Silver/Hydroxyapatite/Tryptophan nanocomposite was reported in the present study. Initially synthesis of silver nanoparticles (AgNPs) was done by the cost effective green method using the flower extract of Aerva lanata. The alkaloids, flavonoids, tannin and polyphenols present in the flower extract were acting as reducing agent for Ag ions. In the synthesis of HAP, Calcium Nitrate Tetrahydrate [CaNO3·4H2O] (0.05 M) and Diammonium Hydrogen Phosphate [(NH4)2 HPO4] were used as precursors and the amino acid tryptophan as a template. The as-synthesized silver nanoparticles, HAP/Tryptophan nanocomposite and Silver/HAP/Tryptophan nanocomposite were characterized by UV–Visible, FT-IR, XRD, SEM and antibacterial studies. All the results were authenticated that the Ag/HAP/Tryptophan nanocomposite can perform as a good biomaterial for bone and tooth replacement applications.

Ultrasound-Assisted Hydroxyapatite-Decorated Breath-Figure Polymer-Derived Ceramic Coatings for Ti6Al4V Substrates.

The introduction of nanoparticles (NPs) into the breath-figure-templated self-assembly (BFTSA) process is an increasingly common method to selectively decorate a surface porous structure. In the field of prosthetic devices, besides controlling the morphology and roughness of the structure, NPs can enhance the osteointegration mechanism because of their specific ion release. Among the most widely used NPs, there are silica and hydroxyapatite (HAp). In this work, we propose a novel one-stage method to fabricate NP-decorated surface porous structures that are suitable for prosthetic coating applications. This technique combines the classical direct BFTSA process with the cavitation effect induced by an ultrasonic atomizer that generates a mist of water droplets with embedded NPs. Coatings were successfully obtained by combining a UV cross-linkable polymer precursor, alkoxy silicone, with synthesized HAp NPs, on Ti6Al4V alloy discs. The cross-linked polymeric surface porous structures at selected concentrations were then pyrolyzed in an ammonia atmosphere to obtain a silicon oxynitride (SiON) ceramic coating. Herein, we report the chemical and morphological analyses of both the polymeric and ceramic coatings as well as the effect of NPs at the interface.

Synthesis of hydroxyapatite nanoparticles by the Sol-Gel method, investigation of its morphology and comparison of its structure with intact tooth

In this study, calcium nitrate tetrahydrate (Ca (NO3)2.4H2O) and phosphorus pentoxide (p < sub>2O5) were used to synthetize hydroxyapatite nanoparticles through the sol-gel method at the ambient temperature. In order to examine the structure and identify the chemical bonds and to compare them with the intact tooth, X-ray diffraction analysis (XRD) and Fourier transform infrared spectrum (FT-IR) were used, respectively. Also, through scanning electron microscope (SEM) images, the microstructure and morphology of both synthesized hydroxyapatite nanoparticles and intact tooth were investigated. The results of X-ray diffraction analysis and Fourier transform infrared spectrum indicated that the produced powder was pure hydroxyapatite, i.e. without any discernible amount of impurity in the sample. Crystal structure of the synthesized hydroxyapatite was nearly identical to the crystal structure of intact tooth; moreover, the chemical bonds of the intact tooth were also seen in hydroxyapatite. Furthermore, the synthesized sample featured a high degree of crystallinity. On the other hand, analysis of SEM images showed that the morphology of the synthesized hydroxyapatite and intact tooth (with nanoscale dimensions and average particle size distribution of 25.69 nm and 23.15 nm, respectively), was almost spherical, thereby confirming the similarity of the synthesized nanoparticle structure to thr intact tooth. In these images, the agglomeration of the synthesized nanoparticles was also seen. Compressive strength of the synthesized sample was equal to 5.5 MPa, which was approximately the same as that of the cancellous bone.

EDTA assisted synthesis of HA nanoparticles and Cobalt-HA nanocomposites

&#x0D; &#x0D; &#x0D; Nano biomaterials such as polymers, ceramics and metals are widely used in bone for regenerative therapies, bone grafts and tissue engineering as well as for temporary or permanent implants to stabilize fractures and replace joints. Bioceramics are specifically developed to replace parts of living system due to its biocompatibility. Hydroxyapatite (HA)Ca10(PO4)6(OH)2 used as a bone substitute material with stoichiometric composition i.e.,Ca/P(ratio) 1.67, which is similar to the mineral phase of the human bone. In this present work, (EDTA) ethylene diamine tetra acetic acid assisted as a capping agent for the synthesis of nano hydroxyapatite and cobalt substituted hydroxyapatite nanocomposites by sol gel method. The synthesized nano-HA powder and Co-HA nanocomposites are further characterized by using FTIR, XRD, SEM, EDAX and anti-bacterial activity. XRD analysis of HA Nanoparticles and Co-HA Nanocomposites, shows the strongest 2θ values at 32.1°,25.91°and at 32.1°, 10.1°, 16.6° respectively. SEM morphology predicts an elongated spherical morphology for HA Nanoparticles and Co-HA Nanocomposites. The elemental composition was confirmed with EDAX analysis and the FTIR spectrum indicates the functional groups of the synthesized compounds. The antibacterial activity was analyzed for both the gram-positive and the gram-negative bacteria’s.&#x0D; &#x0D; &#x0D;

Synthesis of Hydroxyapatite Nanoparticles by Controlled Precipitation in the Presence of Sodium Dodecyl Sulfate

Hydroxyapatite nanoparticles (NPs) have been synthesized by controlled precipitation in the presence of a surfactant, sodium dodecyl sulfate. The sizes, shapes, and structures of the NPs depend on the sequence of mixing the reagents . When the addition of sodium phosphate to a surfactant solution is followed by the addition of calcium nitrate, rodlike hydroxyapatite NPs are formed, the length of which decreases with a rise in surfactant concentration. As the sodium dodecyl sulfate concentration increases, the ζ-potential of the NPs decreases to zero; then, its absolute value grows to –55 mV. This suggests that a surfactant bilayer is formed on the NP surface, with the bilayer shielding the surface of the growing crystals. The shielding leads to the formation of smaller NPs at high surfactant concentrations. When the addition of calcium nitrate to the surfactant solution is followed by the addition of sodium phosphate, the synthesis most likely occurs on the surface of micelles, which partially consist of calcium dodecyl sulfate. Therefore, the sulfate phase remains preserved in the synthesized particles, which is confirmed by X-ray diffraction analysis. At higher surfactant concentrations in the reaction medium, the presence of flexible cylindrical micelles is possible. The precipitation of hydroxyapatite on the surface of such micelles results in the formation of wavy threadlike particles.