HAp Samples Research Articles

Doped hydroxyapatite photocatalyst for efficient degradation of Methylene blue dye

Extensively increasing discharge of organic pollutants and industrial dyes in water necessitates the development of eco-friendly, cost-effective, and sustainable techniques for wastewater treatment. Here, we report the photocatalytic degradation activity of biocompatible and non-toxic copper-doped hydroxyapatite (Cu-HAp) against Methylene blue (MB) dye. A series of Cu-HAp samples were successfully synthesized using the coprecipitation method with varying concentrations of Cu dopant (0, 0.15 %, 0.35 %, 0.55 %, and 0.75 %) on a molar basis. Structural, morphological, and optical properties of Cu-HAp samples were characterized systematically. X-ray diffraction analysis confirmed the hexagonal structure of Cu-HAp. In addition, the EDS results confirmed the presence of Cu dopant in HAp samples. The optical bandgap of HAp decreased from 5.08 to 3.36 eV with increasing the concentration of Cu-dopant up to 0.75 mol%. We observed more than 80 % degradation efficiency for MB dye with 160 min of sunlight exposure. Moreover, the pseudo-first-order- rate constant increased from 0.00218 (HAp) to 0.00935 min−1 (0.75 % Cu-HAp). Our results showed the recyclability and stability of the Cu-HAp photocatalyst followed by four cycles of dye degradation testing. The current study highlights the potential of Cu-HAp to be used as a photocatalyst for wastewater treatment.

Exploring beta irradiation responses in Sr2+-Doped hydroxyapatite: A thermoluminescence study

This research investigates the structural and thermoluminescence (TL) properties of Sr2+-doped Ca5(PO4)3OH (HAp) phosphors. X-ray diffraction (XRD) analysis confirms that HAp has a hexagonal structure with a P63/m space group. The TL behaviour of HAp:Sr2+ phosphors is examined under beta irradiation in the temperature range of 25–500 °C. The study reveals three TL glow peaks at temperatures of 75, 212, and 296 °C. Investigation of TL responses across heating rates (HR) ranging from 0.1 to 5 °C/s shows that higher HRs result in increased maximum TL peak temperatures and reduced TL intensities. This trend suggests an augmented contribution from non-radiative transitions as the heating rate increases. Importantly, no evidence of thermal quenching is found in the HAp samples. Two different methods, Hoogenstraaten's and Booth-Bohun-Porfianovitch, yield consistent activation energy values of 0.50, 1.22, 1.67 eV, and 0.48, 1.19, 1.63 eV, respectively. Reusability assessments indicate a standard deviation of less than 5 %, confirming the reliability of the materials. Tm−Tstop analysis reveals a continuous distribution of trap levels. TL properties in HAp samples have been comprehensively characterized, contributing not only to enhancing our understanding of their behaviour, but also highlighting their potential applications in various areas. The findings of this study have provided valuable insight into the development of efficient catalysts that are suitable for a variety of applications.

Effect of AP distribution on energy release characteristics and functional force of HMX/AP/Al explosives

AbstractIn order to understand the reaction kinetics of HMX/AP/Al ternary system, the different distribution of AP in HMX/AP/Al explosives was realized by two different preparation techniques. Detonation test results show that the detonation velocity, explosion heat and detonation pressure of HAP samples are higher than those of HAl samples, but the extent of improvement is not high, not more than 5 %. The results of scanning electron microscopy showed that AP in HAP samples was distributed on the surface of HMX crystal. AP were dispersed around HMX crystals in HAl samples. The experimental results of explosive fireball performance show that the fireball expansion speed of HAP samples is better than that of HAl samples, demonstrating a good fireball effect. Underwater test results show that the shock wave peak pressure and bubble pulsation period of HAP samples increase by 3.06 % and 7.95 % respectively, and shock wave energy and bubble energy increase by 9.8 % and 25.42 % compared with bubble energy. The experimental results show that HAP samples are superior to HAl samples in accelerating ability of Al flies. The dispersion of AP on the HMX crystal surface promotes the energy release of HMX/AP/Al explosives more.

Comparative analysis of oil absorption and microstructure of fried potato chips treated with different pretreatment via X-ray micro-computed tomography and mercury intrusion method

The porous structure of potato slices has a significant effect on the oil absorption of fried potato chips. In this article X-ray micro-computed tomography and mercury intrusion method have been employed to analyze the potential applications of various pretreatments to modify the microstructure and reduce oil uptake of potato chips. The results showed that hot-air drying (HAP), ultrasound (UP), and ultrasound combined with hot-air drying (UHAP) pretreatments could decrease the oil uptake by 39.17%, 26.78%, and 50.62%, respectively. The pretreatment had an impact on the oil uptake behavior, as the porous structure characteristics were modified during both the pretreatment and frying processes. The pretreated slices had a decreased proportion of large and medium pores, leading to a decrease in structure oil content for the fried HAP and UHAP samples. The fried UHAP samples exhibited the lowest penetrated surface oil of all samples, which was attributed to its lowest percentage of large pores (37.26%). These results demonstrate that micro-CT techniques can be used to effectively characterize the microstructure of potato tissue, thus allowing for a quantitative assessment of how the tissue microstructure influences the oil absorption of potato chips.

Synthesis and Comparison of Chemical Changes Using FTIR Spectroscop for Copper Substituted Hydroxyapatite

The study aims to scrutinise and compare the chemical modifications present in copper-substituted hydroxyapatite utilising FT-IR spectroscopy. The synthesis of both HAp and Cu-modified HAp was conducted via the chemical precipitation method, involving specific chemicals like ammonium hydroxide (HN4OH) solution, diammonium hydrogen phosphate ((NH4)2HPO4), copper chloride hexahydrate (CuCl2.6H2O), and calcium nitrate tetrahydrate (Ca(NO3)2.4H2O). The overall sample size was determined through clinlac.com considering the copper-substituted dataset (N=4), an alpha error of 0.05, G power at 80%, an enrolment ratio of 0.1, and a confidence interval of 95%. The acquired FT-IR spectra denote minimal differences between the CuHAp and HAp samples. Each peak bears a resemblance to the distinctive features of HAp, indicating structural similarity between pure hydroxyapatite and the copper-substituted variant. The investigation utilised SPSS 27.0.1 software to compute the copper-doped hydroxyapatite percentages at 0%, 1%, 5%, and 10%. A One Sample T-test revealed a statistically significant difference with a p-value of 0.001 (p<0.05), particularly highlighting the statistical significance of copper hydroxyapatite weight percentage (p=0.006). Significant alterations in peak values were observed in the novel copper-substituted hydroxyapatite concentrations of 1%, 5%, and 10%. Notably, the study identifies the 10% copper and hydroxyapatite combination as yielding the most noteworthy chemical modifications via spectroscopy. This finding suggests the potential utility of these compounds in medicinal applications.

Different solvents and organic modifiers for the control of crystallographic parameters in nano-crystallite hydroxyapatite for amplification of photocatalytic activity.

In this research, HAp nanocrystals were synthesized using conventional wet chemical precipitation methods using various organic modifiers, including urea, palmitic acid, and naphthalene. Ethanol and isopropyl alcohol (IPA) were used as solvents in this process. Different characterization techniques, namely X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-vis absorption spectroscopy, were employed to ascertain the formation of HAp nanocrystals. Numerous structural parameters, including lattice parameters, unit cell size, volume of the unit cell, specific surface area, degree of crystallinity, dislocation density, macrostrain, and crystallinity index, were assessed using XRD data. The linear straight-line method of Scherrer's equation, Monshi-Scherrer's method, the Williamson-Hall method, the size-strain plot method, the Halder-Wagner method, and Sahadat-Scherrer's model were applied to compute the crystallite size of the synthesized HAp samples. All the synthesized HAp has crystalline structures within the permissible range of 1-150 nm which were estimated from the XRD data using the mentioned models. However, the values for strain (from -3 × 10-4 to 6.4 × 10-3), strain (from -9.599 × 104 to 7 × 1010 N m-2), and energy density (from -11 × 1011 to 2 × 107 J m-3) were also calculated for the synthesized samples. In addition, the optical band gap energy of the synthesized HAp was computed (5.89 to 6.19 eV). The synthesis media have a control on the crystallographic planes, e.g. in the case of the ethanol medium, the (110) plane exhibited significant intensity (which could potentially serve as a driving force for enhancing photocatalytic activity). The use of 100% ethanol HAp yields the most favorable outcome regarding both the degradation percentage (91.79%) and degradation capacity (7%) for the Congo red dye.

Biomineralization and mechanical studies of sodium substituted hydroxyapatite by a time‐saving combustion route

AbstractThe poor biomechanical properties of hydroxyapatite are the major demerits that limit its application in bone tissue engineering to repair critical bone defects. The current study aims to prepare sodium‐substituted Hap samples by using a time‐saving combustion route. Both 5 %Na‐Hap and 10 %Na‐Hap scaffolds together with Hap was analysed by XRD, FTIR, and SEM/EDAX for characterization. Moreover, the influence of sodium substitution on biomineralization, mechanical stability and MG63 cell cytotoxicity was also studied. XRD pattern shows up to 10 mol% of sodium was substituted in the Hap powder without any collapse in its crystal structure. The structural morphology of the Na‐Hap powder was studied using SEM/EDAX. After immersion of Pellets in SBF, the compressive strengths of 5 % Na‐ Hap and 10 % Na‐ Hap were found to be 116 MPa and 98 MPa after the day 9, respectively. The half maximal inhibitory concentration of pure Hap, 5 % Na‐Hap & 10 % Na‐Hap was 59.6, 41.9 and 37.7 μg/ml, respectively. In conclusion, mechanical stability and apatite deposition properties of sodium substituted Hap show significant improvement compared to Pure Hap, and by comparing two different concentrations of sodium substituted Hap, 5 % Na‐Hap shows better apatite deposition and mechanical strength compared to 10 % Na‐Hap.

Evaluation of the acute toxicity by Artemia salina of hydroxyapatite nanoparticles obtained via sol-gel in an aqueous medium without using additives

Hydroxyapatite (Hap) is one of the most important calcium phosphate bioceramics applied to bone tissue regeneration. Synthesizing Hap nanoparticles from easily accessible and low-cost alternative sources of calcium precursors remains a challenge, as well as defining an ideal and reproducible synthesis route without using additives to control the pH of the reaction and entirely performed at room temperature. This study proposes a route for the synthesis of hydroxyapatite by the sol-gel method without the addition of additives for pH control, carried out at room temperature. The Hap samples were characterized by FTIR, XRD, SEM, and BET. The synthesized Hap presented a spherical morphology without the formation of unwanted phases or residues. Samples calcined at 600 and 750 °C resulted in stoichiometric hydroxyapatite with 100% purity and average particle sizes of 24 and 53 nm, respectively. On the other hand, the samples calcined at 900 and 1050 °C presented a specific content of β-calcium phosphate and average particle sizes of 118 and 732 nm, respectively. Acute toxicity was evaluated by Artemia salina nauplii instar I and II for 24 and 48 h of exposure. The tests were conducted on 10, 100, and 1000 ppm of Hap dissolutions. The highest death rate and more significant morphological alterations were observed in A. salina nauplii instar II, exposed to Hap at a concentration of 1000 ppm for 48 h.

Synthesis and fabrication of HAp from fish scale waste to develop bone equivalent phantom

Radiotherapy is one of a method to treat cancer. Before irradiating a patient, we need to understand the dose deposition and interaction of radiation with body. We introduce a tissue equivalent material called phantom to study the interaction and dose deposition. This study mainly focuses to understand the interaction of radiation with the bones. Since there are many tissue equivalent phantoms available and are in use and there is no bone equivalent phantom, there is a need of phantom which should be bone equivalent. Thus our study focuses on fabrication of bone equivalent phantom that too made of fish shell waste, which make it easy to synthesis and makes it environment friendly. The fabrication and synthesis of Hap from fish scale waste by undergoing a series of processes to develop bone equivalent calcined and uncalcined samples were made. Before its been exposed using a Linear accelerator (Varian – Unique performance), the fabricated HAp samples undergone a CT test to verify the Hounsfield unit with the value that of bones in humans. After the confirmation of CT number of the fabricated samples and its exposure with the LINAC for different MUs (300 Mu/min and 500 MU/min), it's been read by a TLD reader and GM counter. Finally the readings from the TLD and GM counter of the exposed calcined and uncalcined samples were compared to understand the efficiency of both the samples.

Fabrication and Characterisation of Calcium Sulphate Hemihydrate Enhanced with Zn- or B-Doped Hydroxyapatite Nanoparticles for Hard Tissue Restoration.

A composite based on calcium sulphate hemihydrate enhanced with Zn- or B-doped hydroxyapatite nanoparticles was fabricated and evaluated for bone graft applications. The investigations of their structural and morphological properties were performed by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) spectroscopy techniques. To study the bioactive properties of the obtained composites, soaking tests in simulated body fluid (SBF) were performed. The results showed that the addition of 2% Zn results in an increase of 2.27% in crystallinity, while the addition of boron causes an increase of 5.61% compared to the undoped HAp sample. The crystallite size was found to be 10.69 ± 1.59 nm for HAp@B, and in the case of HAp@Zn, the size reaches 16.63 ± 1.83 nm, compared to HAp, whose crystallite size value was 19.44 ± 3.13 nm. The mechanical resistance of the samples doped with zinc was the highest and decreased by about 6% after immersion in SBF. Mixing HAp nanoparticles with gypsum improved cell viability compared to HAp for all concentrations (except for 200 µg/mL). Cell density decreased with increasing nanoparticle concentration, compared to gypsum, where the cell density was not significantly affected. The degree of cellular differentiation of osteoblast-type cells was more accentuated in the case of samples treated with G+HAp@B nanoparticles compared to HAp@B. Cell viability in these samples decreased inversely proportionally to the concentration of administered nanoparticles. From the point of view of cell density, this confirmed the quantitative data.

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.

Enhancement of Fracture Toughness in carbonate doped Hydroxyapatite based nanocomposites: Rietveld analysis and Mechanical behaviour

Highly nanocrystalline carbonated hydroxyapatite (CHAp) is synthesized by hydrothermal technique with four different stoichiometric compositions for microstructural and mechanical analysis. HAp is one of the most biocompatible material and addition of carbonate ions lead to increase in fracture toughness highly required in biomedical applications. The structural properties and its purity as single phase is confirmed by X-ray diffraction. Lattice imperfections and structural defects is investigated using XRD pattern model simulation, i.e. Rietveld's analysis. The substitution of CO32− in HAp structure leads to a decrease in crystallinity which ultimately lessens crystallite size of sample as verified by XRD analysis. FE-SEM micrographs confirms the formation of nanorods with cuboidal morphology and porous structure of HAp and CHAp samples. The particle size distribution histogram validates the constant decrease in size due to carbonate addition. The mechanical testing of prepared samples revealed the increase in mechanical strength from 6.12 MPa to 11.52 MPa due to the addition of carbonate content, which leads to a rise in fracture toughness, a significant property of an implant material from 2.93 kN to 4.22 kN. The cumulative effect of CO32− substitution on HAp structure and mechanical properties has been generalized for the application as biomedical implant material or biomedical smart materials.

Cytotoxic and osteogenic property of trilaurin assisted hydroxyapatite nanorods in simulated body fluid environment

In this research work, the cytogenic and osteogenic properties of biomimetically synthesised nanohydroxyapatite (nanoHAP) powders using Trilaurin (TL), as a surfactant was attempted. Microwave (MW) and ultrasound (US) technologies were also employed to enhance the efficacy of the method. Different HAP samples were prepared using 1.5 times concentrated Simulated Body Fluid (SBF) with 1, 5 and 15 days immersion inorder to achieve pure nanohydroxyapatite powders. The formation of HAP was well supported by FTIR and Raman spectroscopy, which shows no impurity peaks. By increasing the time of soaking in SBF, growth, size and crystallinity of HAP were found to decrease as evidenced by XRD data. HRSEM studies reveal that nano-plates and rod shaped nano HAP could be obtained by this method. So the obtained TL assisted HAP exhibits high thermal stability as confirmed by TGA analysis. The invitro cytotoxicity was evaluated by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-tetrazolium bromide (MTT) assay using human osteoblastic cell line (MG-63) and Michigan Cancer Foundation-7 (MCF-7) breast cancer cell line. The obtained result supports the osteoblast property and less toxicity. Inorder to further prove the osteoblast property, trypan blue exclusion test (live dead assay) were carried out using MG-63 cell line and the obtained results favours the bone forming ability.

Removal of Cu2+ from wastewater using eco-hydroxyapatite synthesized from marble sludge

Rapid development brings environmental problems such as the discharge of industrial and agricultural wastewater. This study demonstrates the synthesis of eco–hydroxyapatite (eco–HAp) through the hydrothermal processing of marble sludge for the removal of Cu2+ from wastewater. FTIR analysis confirmed the existence of O–H and PO43− groups in eco–HAp samples. TEM analysis revealed the importance of Ca/P ratio on the shape and size of particles. Solid–state nuclear magnetic resonance (NMR) spectra revealed NMR 1H representing a single crystal site of (OH) and 31P representing the single crystal position of inorganic phosphorus (PO4). Eco–HAp samples presented Type IV N2 adsorption–desorption isotherms with H3 hysteresis loops, typical of HAp samples with a well–defined capillary step, which is indicative of mesoporous materials. Eco–HAp fabricated at a hydrothermal temperature of 120 °C and Ca/P molar ratio of 1 presented high adsorption capacity of 256.25 mg/g. The correlation between the eco–HAp and the Langmuir adsorption isotherm model was 0.96–0.99. Eco–HAp with a large surface area is thus an excellent adsorbent for the treatment of wastewater containing Cu2+.

Hydroxyapatite from Natural Sources for Medical Applications.

The aim of this work is to study the physical-chemical, mechanical, and biocompatible properties of hydroxyapatite obtained by hydrothermal synthesis, at relatively low temperatures and high pressures, starting from natural sources (Rapana whelk shells), knowing that these properties influence the behavior of nanostructured materials in cells or tissues. Thus, hydroxyapatite nanopowders were characterized by chemical analysis, Fourier-transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), scanning electron microscopy (SEM), and X-ray diffraction (XRD). In vitro studies on osteoblast cell lines (cytotoxicity and cell proliferation), as well as preliminary mechanical tests, have been performed. The results showed that the obtained powders have a crystallite size below 50 nm and particle size less than 100 nm, demonstrating that hydrothermal synthesis led to hydroxyapatite nanocrystalline powders, with a Ca:P ratio close to the stoichiometric ratio and a controlled morphology (spherical particle aggregates). The tensile strength of HAp samples sintered at 1100 °C/90 min varies between 37.6–39.1 N/mm2. HAp samples sintered at 1300 °C/120 min provide better results for the investigated mechanical properties. The coefficient of friction has an appropriate value for biomechanical applications. The results of cell viability showed that the cytotoxic effect is low for all tested samples. Better cell proliferation is observed for osteoblasts grown on square samples.

Citric Acid-Mediated Microwave-Hydrothermal Synthesis of Mesoporous F-Doped HAp Nanorods from Bio-Waste for Biocidal Implant Applications.

In this current research, mesoporous nano-hydroxyapatite (HAp) and F-doped hydroxyapatite (FHAp) were effectively obtained through a citric acid-enabled microwave hydrothermal approach. Citric acid was used as a chelating and modifying agent for tuning the structure and porosity of the HAp structure. This is the first report to use citric acid as a modifier for producing mesoporous nano HAp and F-doped FHAp. The obtained samples were characterized by different analyses. The XRD data revealed that F is incorporated well into the HAp crystal structure. The crystallinity of HAp samples was improved and the unit cell volume was lowered with fluorine incorporation. Transmission electron microscopy (TEM) images of the obtained samples revealed that a nano rod-like shape was obtained. The mesoporous structures of the produced HAp samples were confirmed by Brunauer–Emmett–Teller (BET) analysis. In vivo studies performed using zebrafish and C. elegans prove the non-toxic behavior of the synthesized F doped HAp samples. The obtained samples are also analyzed for antimicrobial activity using Gram-negative and Gram-positive bacteria, which are majorly involved in implant failure. The F doped samples revealed excellent bactericidal activity. Hence, this study confirms that the non-toxic and excellent antibacterial mesoporous F doped HAp can be a useful candidate for biocidal implant application.

Amalgamation of nano hydroxyapatite bioceramics for electrical and optical studies

Calcium phosphate minerals (HAp) are the key component of human bones and teeth. The HAp nanorods can perform a good biocompatibility and bioactivity. In this work, HAp powders are synthesized via a simple route by hydrothermal treatment. The resultant HAp samples are rod-like crystalline, where the morphological and particle dimensions can be customized by changing the pH conditions. The prepared HAp powder samples confirmation results are discussed using FT-IR, scanning electron microscopy, XRD, and impedance spectroscopy. FT-IR investigation confirmed that the occurrence of phosphate, carbonate and water molecules for all the samples and the transmittance decreases with pH. The acidic, base and alkaline nature of the synthesised samples are analysed using XRD studies. It results as the pH increases, significant reduction in crystallites size of HAp occurs. The average crystalline size of HAp nanorod is maximum (43.089 nm) for pH4. The SEM images of the synthesized HAp samples obtained, displays nanorods with excellent uniformity which depends on pH value. The particle diameter is estimated in the range of 10 nm to 45 nm. Electrical conductivity and dielectric function are studied using impedance spectroscopy. It can be massively helpful recognition for the presence of conduction mechanism in the synthesised HAp samples. The electrical and the optical properties may be tuned by altering the pH value which is concluded from the current work.

Solid-State NMR and Raman Spectroscopic Investigation of Fluoride-Substituted Apatites Obtained in Various Thermal Conditions.

Fluoride-substituted apatites were synthesized by the standard sol-gel method and then calcined at three different temperatures: 800 °C, 1000 °C, and 1200 °C. Using a similar method, hydroxyapatite was synthesized and used as a reference material. The obtained powders were characterized by physicochemical methods: powder X-ray diffractometry, Raman spectroscopy, transmission electron microscopy, and solid-state nuclear magnetic resonance. All these methods allowed to identify additional α-TCP phase (tricalcium phosphate) in the HAP samples heated at 1000 °C and 1200 °C while fluoridated apatites turned out to be thermally stable. Moreover, Raman spectroscopy and NMR allowed to establish that the powders substituted with fluoride ions are not pure fluorapatite and contain OH- groups in the crystal structure. All the obtained materials had crystals with a shape similar to that of biological apatite.

Synthesis of luminescent Mg-incorporated hydroxyapatite by reflux condensation method: Photoluminescence, in-vitro drug release and kinetic studies

The role of biomaterials in the field of medicine has immense applications because they are engineered to be in close proximity to the biological organ or tissue and thereby healing or replacing the damaged tissues or organs. These biomaterials are of natural and synthetic made of different components to interact with the biological system. They can be tailored in such a way either for therapeutic or diagnostic purposes. The focus of the present study is to prepare nanosized magnesium doped hydroxyapatite (Mg-HAp) using magnesium nitrate as the source of magnesium (Mg). The reflux condensation method was used to synthesize pure HAp and Mg-HAp samples that were subjected to microwave irradiation. XRD studies verify that the integration of Mg into HAp did not bring about any phase changes in HAp. Further, the changes in the lattice parameters of Mg-HAp show that Mg is well incorporated into the HAp lattice. FTIR and Raman spectroscopic investigations show the absence of the hydroxyl group, which adds to the confirmation of Mg substitution in the HAp lattice. Crystallinity and size of the Mg-HAp decreased for microwave irradiated samples compared to as-synthesized samples because of the uniform heating of the sample. The morphology of Mg-HAp samples further indicates that particle size reduces with increasing Mg concentration which was proven by SEM results. Photoluminescence spectra of microwave irradiated Mg-HAp samples exhibit increased intensity for increased Mg concentration because of the blocking of recombination of charge carriers. The self-luminescent property of Mg-HAp particles, which is because of their surface plasmon, can be used in imaging and drug delivery applications.

Coupled effect of particle size of the source materials and calcination temperature on the direct synthesis of hydroxyapatite.

We report the effect of controlled particle size (obtained by using 80, 100, 120, 140 and 200 mesh) of the source materials on the synthesis of a well-known biomaterial, hydroxyapatite (Hap). In addition to this, we have also mapped the consequence of applied temperature (700°C, 800°C and 900°C) on the crystallographic properties and phase composition of the obtained Hap. Nevertheless, although with Hap, in each case, β-tricalcium phosphate (β-TCP) was registered as the secondary phase the ANOVA test revealed that the results of the crystallographic parameters are significantly different for the applied sintering temperature 700°C and 800°C (p < 0.05), while the data obtained for calcination temperature 800°C are not significantly different from that acquired at 900°C (p > 0.05). Fourier transform infrared spectrophotometer data ensured that, irrespective of mesh size and calcination temperature, the synthesized Hap samples were of carbonated apatite with B-type substitution. Interestingly, for all cases, the % of carbonate content was below the maximum limit (8%) of the ion present in bone tissue hydroxyapatite.