scholarly journals Modulated Monoclinic Hydroxyapatite: The Effect of pH in the Microwave Assisted Method

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 314
Author(s):  
Daniel Sánchez-Campos ◽  
Maria Isabel Reyes Valderrama ◽  
Susana López-Ortíz ◽  
Daniela Salado-Leza ◽  
María Eufemia Fernández-García ◽  
...  
Keyword(s):  
Calcium Nitrate ◽  
Ammonium Phosphate ◽  
Ammonium Hydroxide ◽  
Average Crystallite Size ◽  
Rietveld Analysis ◽  
Calcium Nitrate Tetrahydrate ◽  
Absorption Bands ◽  
Effect Of Ph ◽  
Microwave Assisted ◽  
Transmission Electron

Hydroxyapatite (HAp) is a natural hard tissue constituent widely used for bone and tooth replacement engineering. In the present work, synthetic HAp was obtained from calcium nitrate tetrahydrate (Ca(NO3)2·4H2O) and ammonium phosphate dibasic (NH4)2HPO4 following an optimized microwave assisted hydrothermal method. The effect of pH was evaluated by the addition of ammonium hydroxide (NH4OH). Hence, different characterization techniques were used to determine its influence on the resulted HAp powders’ size, shape, and crystallinity. By Transmission Electron Microscopy (TEM), it was observed that the reaction pH environment modifies the morphology of HAp, and a shape evolution, from sub-hedral particles at pH = 7 to rod-like nanosized HAp at pH = 10, was confirmed. Using the X-ray Diffraction (XRD) technique, the characteristic diffraction peaks of the monoclinic phase were identified. Even if the performed Rietveld analysis indicated the presence of both phases (hexagonal and monoclinic), monoclinic HAp prevails in 95% with an average crystallite size of about 23 nm. The infrared spectra (FTIR) showed absorption bands at 3468 cm−1 and 630 cm−1 associated with OH− of hydroxyapatite, and bands at 584 cm−1, 960 cm−1, and 1090 cm−1 that correspond to the PO43− and CO32− characteristic groups. In summary, this work contributes to obtaining nanosized rod-like monoclinic HAp by a simple and soft method that has not been previously reported.

Synthesis of Pure Hydroxyapatite (Ca10(PO4)6(OH)2) by the Sol–Gel Method and the Antibiotic Loaded in the Presence of Natural Polymer for the Application of Drug Delivery

2018 ◽  
Vol 24 (8) ◽  
pp. 5523-5526 ◽  
Author(s):  
B Shalini ◽  
A. Ruban Kumar ◽  
A. Mary Saral
Keyword(s):  
Ph Value ◽  
Drug Loading ◽  
Sol Gel ◽  
Calcium Nitrate ◽  
Average Crystallite Size ◽  
Ammonia Solution ◽  
Calcium Nitrate Tetrahydrate ◽  
Gel Method ◽  
Sol Gel Method ◽  
Nitrate Tetrahydrate

Hydroxyapatite (HAp) is the most widely accepted biomaterial for the repair and reconstruction of bone tissue defects. The current study is based on HAp was synthesized using sol–gel method. The drug was loaded in presence and absence of gelatin with pure HAp. Precursors like calcium nitrate tetrahydrate and diammonium hydrogen orthophosphate were used and ammonia solution was added to maintain the pH value at 10.5 throughout the reaction. The synthesized HAp, drug loaded HAp and drug loaded HAp with gelatin were characterized using PXRD, FTIR, SEM, Drug loading, drug release studies. Results shows that the average crystallite size of the prepared HAp and drug loaded HAp with gelatin are 30 to 60 nm and 100 to 300 nm respectively was calculated using PXRD and morphology of pure HAp and drug loaded HAp with polymer was found using SEM. Drug loading and release percentage was calculated.

Synthesis and characterization of pure and nanosized hydroxyapatite bioceramics

2017 ◽  
Vol 6 (2) ◽  
pp. 149-157 ◽  
Author(s):  
Aneela Anwar ◽  
Qudsia Kanwal ◽  
Samina Akbar ◽  
Aisha Munawar ◽  
Arjumand Durrani ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Calcium Nitrate ◽  
Temperature Stability ◽  
Molar Ratio ◽  
Calcium Nitrate Tetrahydrate ◽  
High Temperature Stability ◽  
X Ray ◽  
Transmission Electron ◽  
Nanosized Hydroxyapatite ◽  
Co Precipitation

AbstractSynthetic nanosized hydroxyapatite (HA) particles (<120 nm) were prepared using a co-precipitation technique by adopting two different routes – one from an aqueous solution of calcium nitrate tetrahydrate and diammonium hydrogen phosphate at pH 10 and the other by using calcium hydroxide and phosphoric acid as precursors at pH 8.5 and reaction temperature of 50°C. The lattice parameters of HA nanopowder were analogous to reference [Joint Committee on Powdered Diffraction Standards (JCPDS)] pattern no. 09-432. No decomposition of HA into other phases was observed even after heating at 1000°C in air for 1 h. This observation revealed the high-temperature stability of the HA nanopowder obtained using co-precipitation route. The effects of preliminary Ca/P molar ratio, precipitation, pH and temperature on the evolution of phase and crystallinity of the nanopowder were systematically examined and optimized. The product was evaluated by techniques such as X-ray-diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and Raman spectroscopy analyses. The chemical structural analysis of the as-prepared HA sample was performed using X-ray photoelectron spectroscopy (XPS). After heat treatment at 1000°C for 1 h and ageing for 15 h, the product was obtained as a phase-pure, highly crystalline HA nanorods.

Influence of the Precipitation Temperature on Properties of Nanohydroxyapatite Powder for the Fabrication of Highly Porous Bone Scaffolds

2013 ◽  
Vol 587 ◽  
pp. 27-32 ◽  
Author(s):  
Cristian Parisi ◽  
Francesca Gervaso ◽  
Francesca Scalera ◽  
Sanosh Kunjalukkal Padmanabhan ◽  
Concetta Nobile ◽  
...  
Keyword(s):  
Calcium Nitrate ◽  
Bone Substitutes ◽  
Porous Scaffolds ◽  
Calcium Nitrate Tetrahydrate ◽  
High Porosity ◽  
Precipitation Temperature ◽  
Transmission Electron ◽  
Nitrate Tetrahydrate ◽  
Different Temperatures ◽  
Highly Porous

The aim of the present work is to study the influence of the precipitation temperature in the synthesis of nanohydroxyapatite (n-HAp) on the properties of the resulting n-HAp powder for the fabrication of highly porous scaffolds for bone tissue engineering. The n-HAp powder was obtained by a wet precipitation technique starting from calcium nitrate tetrahydrate (Ca (NO3)2*4H2O) and phosphoric acid (H3PO4) at different temperatures: 10°C, 37°C and 50°C. Highly porous scaffolds were fabricated using the three different powders by the sponge replica method and sintering at 1300°C. Combined X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses on powders indicated that on increasing the precipitation temperature the formation of pure n-HAp is accelerated, without significant changes in particles morphology and size. Scaffolds characterized by high porosity (89%) and good compressive strength (0.53 MPa for n-HAp prepared at 37°C) were obtained. XRD analyses on sintered n-HAp confirmed the thermal stability of the material. Therefore, the as-synthesized n-HAp powder can be successfully used for the fabrication of highly porous scaffolds as bone substitutes.

Biofilms of cellulose and hydroxyapatite composites: Alternative synthesis process

2020 ◽  
Vol 35 (6) ◽  
pp. 469-478
Author(s):  
Cari M Pieper ◽  
Wellington LO da Rosa ◽  
Rafael G Lund ◽  
Adriana F da Silva ◽  
Evandro Piva ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Water Solution ◽  
Calcium Nitrate ◽  
Morphological Properties ◽  
Synthesis Process ◽  
Calcium Nitrate Tetrahydrate ◽  
X Ray Diffraction ◽  
Good Thermal Stability ◽  
Microwave Assisted ◽  
Nitrate Tetrahydrate

A new biofilm of cellulose coated with hydroxyapatite particles have been prepared using a simple, fast and low temperature process based on a microwave-assisted hydrothermal synthesis. The cellulose used as matrix of the biocomposite was extracted from banana stems residues. The hydroxyapatite coating was performed using calcium nitrate tetrahydrate, phosphoric acid, and 1,2-ethylenediamine dispersed in a cellulose/water solution, with posterior microwave-assisted hydrothermal synthesis, for 5 min at 140°C. The chemical, structural, thermal, and morphological properties of the composites were investigated by X-ray diffraction, infrared spectroscopy, thermogravimetry and field emission scanning electron microscopy. Results showed that the methodology was effective to produce high quality composites, with good thermal stability. Cell viability tests indicated that the cellulose/Hap films were not cytotoxic.

scholarly journals Synthesis of Graphene Nanoribbons–Hydroxyapatite Nanocomposite Applicable in Biomedicine and Theranostics

2020 ◽  
Vol 1 (1) ◽  
pp. 6-18 ◽  
Author(s):  
Hassan Nosrati ◽  
Rasoul Sarraf-Mamoory ◽  
Amir Hossein Ahmadi ◽  
Maria Canillas Perez
Keyword(s):  
Solvothermal Method ◽  
Graphene Nanoribbons ◽  
Calcium Nitrate ◽  
Hydrogen Gas ◽  
Calcium Nitrate Tetrahydrate ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Nitrate Tetrahydrate ◽  
Spark Plasma ◽  
The Difference

In order to investigate the effect of graphene nanoribbons on the final properties of hydroxyapatite-based nanocomposites, a solvothermal method was used at 180 °C and 5 h for the synthesis of graphene nanoribbons–hydroxyapatite nanopowders by employing hydrogen gas injection. Calcium nitrate tetrahydrate and diammonium hydrogenphosphate were used as calcium and phosphate precursors, respectively. To synthesize the powders, a solvent containing diethylene glycol, anhydrous ethanol, dimethylformamide, and water was used. Graphene oxide nanoribbons were synthesized by chemical unzipping of carbon nanotubes under oxidative conditions. The synthesized powders were consolidated by spark plasma sintering methodat 950 °C and a pressure of 50 MPa. The powders and sintered samples were then evaluated using X-ray diffraction, Raman spectroscopy, high-resolution transmission electron microscopy, Vickers microindentation techniques, and biocompatibility assay. The findings of this study showed that the final powders synthesized by the solvothermal method had calcium to phosphate ratio of about 1.67. By adding a small amount of graphene nanoribbon (0.5%W), elastic modulus and hardness of hydroxyapatite increased dramatically. In biological experiments, the difference of hydroxyapatite effect in comparison with the nanocomposite was not significant. The findings of this study showed that graphene nanoribbons have a positive effect on the properties of hydroxyapatite, and these findings would be useful for the medical and theranostic application of this type of nanocomposites.

Effect of Capping Agent on Physicochemical Properties of Zinc Substituted Nanoscale Hydroxyapatite

2013 ◽  
Vol 856 ◽  
pp. 304-308
Author(s):  
Seema Kapoor ◽  
Uma Batra ◽  
Suchita Kohli
Keyword(s):  
Calcium Nitrate ◽  
Potassium Dihydrogen Phosphate ◽  
Average Crystallite Size ◽  
Particle Growth ◽  
Zinc Nitrate ◽  
Bet Surface Area ◽  
Dihydrogen Phosphate ◽  
Calcium Nitrate Tetrahydrate ◽  
Capping Agent ◽  
Nitrate Tetrahydrate

Nanoscale zinc substituted hydroxyapatite has been synthesized by solgel technique at 70 C using an aqueous solution of calcium nitrate tetrahydrate (CNT), zinc nitrate tetrahydrate (ZNT) and potassium dihydrogen phosphate (KDP) as starting materials with or without a capping agent, triethanolamine (TEA). The synthesized nanopowders were calcined at two temperatures 800 C and 1000 C for 1 hr. The morphology and size of nanopowders were characterized by transmission electron microscopy. The BET surface area was evaluated from N2 adsorption isotherms. Structural analysis and thermal behavior were investigated by means of Fourier transform infrared spectroscopy, x-ray diffraction and thermogravimetry. The results of TEM confirmed that TEA is effective in reducing average crystallite size from 15 nm in case of zinc substituted hydroxyapatite without TEA (ZnHA) to 9 nm in case of zinc substituted hydroxyapatite with TEA (ZnHA-TEA). FTIR spectra showed the presence of weaker HPO4 bands and stronger O-H bands in case of ZnHA as compared to ZnHA-TEA, which indicated that the formation of the latter is delayed due to TEA assistance. TGA study revealed that ZnHA is thermally more stable as compared to ZnHA-TEA. These results show that the introduction of capping agent effectively restricts the particle growth during precipitation as well as on calcination.

A Novel Mixed Hydroxide Method for Hydroxyapatite Preparation

2010 ◽  
Vol 152-153 ◽  
pp. 1399-1403 ◽  
Author(s):  
Mei Mei Zhang ◽  
Hong Shi Zhao ◽  
Hong Liu ◽  
Jian An Liu ◽  
Xiu Xiu Han ◽  
...  
Keyword(s):  
Raw Materials ◽  
Calcium Nitrate ◽  
Nano Particles ◽  
Calcium Nitrate Tetrahydrate ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Nitrate Tetrahydrate ◽  
Pure Phase ◽  
Temperature Time ◽  
Nano Size

Hydroxyapatite(HAP) nanoparticles were synthesized by a mixed hydroxide method using calcium nitrate tetrahydrate[Ca(NO3)24H2O] and phosphoric pentoxide(P2O5) as raw materials. The synthesized nanoparticles were analyzed by x-ray diffraction (XRD), infrared spectroscopy (IR) and transmission electron microscopy (TEM) methods. The effects of reaction temperature, time and concentration of reactants on the microstructure of the nano-particles have been discussed. The results show that the hydroxyapatite particles synthesized have features of uniform morphology, pure phase and well crystallized nano size. The particle size is in the range of 30-200 nm.

scholarly journals Gradual Replacement of Ca2+ with Mg2+ Ions in Brushite for the Production of Ca1−xMgxHPO4·nH2O Materials

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 284
Author(s):  
Mazen Alshaaer ◽  
Khalil Issa ◽  
Abdulaziz Alanazi ◽  
Saida Abu Mallouh ◽  
Ahmed S. Afify ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Calcium Nitrate ◽  
Ammonium Hydroxide ◽  
Magnesium Nitrate ◽  
Molar Ratio ◽  
Partial Replacement ◽  
Nitrate Hexahydrate ◽  
Calcium Nitrate Tetrahydrate ◽  
X Ray ◽  
Starting Solution

The present study investigates the gradual replacement of Ca2+ with Mg2+ ions in brushite (CaHPO4·2H2O). To date, this approach has not been systematically explored and may prove beneficial for the production of Ca1−xMgxHPO4·nH2O materials with tailored properties which are suitable for environmental and medical applications. For their production, solutions of sodium dihydrogen orthophosphate dehydrate, NaH2PO4·2H2O, calcium nitrate tetrahydrate, Ca(NO3)2·4H2O, magnesium nitrate hexahydrate, Mg(NO3)2·6H2O and ammonium hydroxide solution, NH4OH, were used. At low Mg/Ca molar ratios (up to 0.25) in the starting solution, partial replacement of Ca with Mg takes place (Mg doping) but no struvite is produced as discrete phase. When the Mg/Ca molar ratio increases gradually to 1.5, in addition to Mg-doped brushite, struvite, NH4MgPO4·6H2O, precipitates. The microstructure of the materials produced for different degrees of Ca replacement with Mg has been analyzed in depth with the use of powdered XRD (X-ray diffraction), XPS (X-ray photoelectron spectroscopy), thermogravimetric (TG) analysis and SEM (scanning electron microscopy). The results of this study prove that the Mg/Ca ratio in the starting solution can be monitored in such a way that materials with tailored composition are obtained.

scholarly journals Effect of Ca2+ Replacement with Cu2+ Ions in Brushite on the Phase Composition and Crystal Structure

Minerals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1028
Author(s):  
Mazen Alshaaer ◽  
Juma’a Al-Kafawein ◽  
Ahmed S. Afify ◽  
Nagat Hamad ◽  
Ghassan Saffarini ◽  
...  
Keyword(s):  
Calcium Nitrate ◽  
Ammonium Hydroxide ◽  
Copper Nitrate ◽  
Molar Ratio ◽  
Calcium Nitrate Tetrahydrate ◽  
Molar Ratios ◽  
Starting Solution ◽  
Novel Approach ◽  
Nitrate Tetrahydrate ◽  
Microscopy Techniques

The gradual replacement of Ca2+ with Cu2+ ions in brushite (CaHPO4·2H2O) has been extensively studied and discussed. The approach adopted in this work has not been systematically explored in previous studies. This novel approach may prove beneficial for the production of Ca1−xCuxHPO4·nH2O materials with desired properties suitable for medical applications. Solutions of sodium dihydrogen orthophosphate dihydrate, NaH2PO4·2H2O, calcium nitrate tetrahydrate, Ca(NO3)2·4H2O, copper nitrate trihydrate, Cu(NO3)2·3H2O, ammonium hydroxide solution, and diluted HCl were used for the preparation of these materials. At low Cu/Ca molar ratios (up to 0.25) in the starting solution, biphasic phosphate minerals were formed: brushite and sampleite. When the Cu/Ca molar ratio increases gradually from 0.67 to 1.5, sampleite-like mineral precipitates. Powdered XRD (X-ray diffraction), thermogravimetric (TG) analysis, and SEM (scanning electron microscopy) techniques were employed for the study of the microstructure of the produced materials for different degrees of Ca replacement with Mg. It is found that the Cu/Ca ratio in the starting solution can be adjusted to obtain materials with tailored composition. Thus, a new method of sampleite-like synthesis as a rare mineral is introduced in this study. Both phosphate minerals brushite and sampleite-like minerals are attractive as precursors of bioceramics and biocements. The search for such products that may decrease the possibility of post prosthetic or implant infection can be crucial in preventing devastating post-surgical complications.

Sodium-Doped Hydroxyapatite Nanopowder through Sol-Gel Method: Synthesis and Characterization

2011 ◽  
Vol 694 ◽  
pp. 128-132 ◽  
Author(s):  
Erlani Pusparini ◽  
Iis Sopyan ◽  
Mohd. Hamdi ◽  
Singh Ramesh
Keyword(s):  
Sol Gel ◽  
Calcium Nitrate ◽  
Xrd Analysis ◽  
Sodium Concentration ◽  
Calcium Nitrate Tetrahydrate ◽  
X Ray Diffraction ◽  
Gel Method ◽  
Sol Gel Method ◽  
Transmission Electron ◽  
Nitrate Tetrahydrate

The nanocrystalline HA powders were produced through sol-gel method which employed calcium nitrate tetrahydrate [Ca(NO3)2.4H2O] and diammonium hydrogen phosphate [(NH4)2HPO4] as calcium and phosphorous precursors. Sodium ion (Na+) is one of the trace elements found in biological apatite and believed to have important effect in its performance. The concentrations of sodium dopant were varied from 0 mol% until 15 mol% by using sodium nitrate (NaNO3) as the source of dopant. Characterization of nanopowders was investigated by using X-ray diffraction (XRD), Fourier transform infra red (FTIR) and Transmission Electron Microscope (TEM). XRD analysis revealed that there are no other phases exist in the synthesized powder, evinced single phase of HA and a trend shows an increase of cristallinity with increase of sodium dopant concentration. While the TEM images showed evidence that the particle sizes were bigger with the increasing sodium concentration, showing the effect of sodium dopant on the densification of the powder.

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