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Showing 10 results for Hydroxyapatite

Javadpour J., Sakhaii K., Masihiyanpour A.a.,
Volume 1, Issue 4 (12-2004)
Abstract

Thin sheets of hydroxyapatite were fabricated by tape casting process. The non-aqueoustape casting formulation was optimized by adjusting the concentration of organic additivesspecially those of binder and plasticizer in the slurry. The optimized slurry was cast on a glasscarrier using a designed laboratory scale doctor blade. Following a binder removal stage, thetapes were sintered at different temperatures in air atmosphere. Heat treatment at 1250 °C led tothe formation of a dense microstructure as was evidenced by the scanning electron microscopy.
Nojehdehyan H., Moztar Zadeh F., Mir Zadeh Hamid, Hesaraki S., Keyanpour-Rad M.,
Volume 2, Issue 2 (6-2005)
Abstract

The effect of addition of NaHF2 on the cement setting and the set mass has been studied as an initial step to determine how fluoride influences the characteristics of a calcium phosphate cement, consisting of tetracalcium phosphate [TTCP:Ca4 (PO4)2O] and dicalcium phosphate dihydrate [DCPD:CaHPO4.2H2O].NaHF2 [0-10% wt% of powder phase] has been dissolved in double distilled water and used as the liquid phase of the apatite cement (AC). Powder X-ray diffraction analysis and FTIR measurements revealed that fluoride was necessary in promoting the formation of the apatite phase. The setting time was decreased significantly by the addition of NaHF2from 0% to 6%, but increased resulted in the AC (8-10%). The set AC (2%) has the highest compressive strength and the lowest porosity.The dissolution rate of set AC in weak acid, pH 5.5, was decreased with the amount of added NaHF2 from 0% to 6% but increased in the set AC 8-10%.The formation of fluoroapatite in AC (6%) was provided the low solubility and good acid resistance which is necessary for dental application.SEM observation showed needle-like apatite crystal growth over particulate matrix surface, however the amount of non-reactive TTCP or DCPD particles decreased by the addition of NaHF2. The Ca/P ratio, which was determined by EDAX, increased significantly with the addition of NaHF2.
Baradari H., Amani Hamedani H., Karimi Khoygani S., Rezaei H.r., Javadpour J., Sar Poulaki H.,
Volume 3, Issue 1 (6-2006)
Abstract

Ultrafine hydroxyapatite (HAp) powders with crystallite size in the range of 10-90 nm were synthesized by chemical precipitation process using Ca(OH)2 and H3PO4 solutions as starting materials. Molar ratio of Ca/P=1.68 was kept constant throughout the process and alkaline condition for the reaction was maintained using ammonium hydroxide. The role of raw material concentration on HAp crystallite size and morphology were investigated using X-ray diffraction (XRD) and scanning electron microscope (SEM) techniques. The results revealed that variations in crystallite size and morphology of synthesized HAp are strongly affected by the concentration of acid solution. To study the sintering behavior of HAp particles, the powders were pressed at 200 MPa using a uniaxial press. Sintering experiments were carried out at temperatures of 1100, 1250 and 1300°C with various soaking times at maximum temperatures. XRD was also used in determining thephases present after sintering process. The results indicated the decomposition of HAp into a-tricalcium phosphate (TCP) and b-TCP phases at 1300°C. The microstructure of the sintered HAp ceramics was characterized by SEM.
Saremi M., Motaghi Golshan B.,
Volume 3, Issue 3 (12-2006)
Abstract

A film of osteoconductive and biocompatible material on biomedical metallic implants can create bioactivity of the implant and shorten healing time. Hydroxyapatite, that is the most important mineral part of human bone, was coated on Ti6Al4V using cathodic electrode position process. Pulse electrode position technique was used and the effects of different parameters such as potential, duty cycle (on time/ (on time+ off time)), temperature and current density on the morphology of the deposits were examined. Nano size deposits were formed under controlled temperature and optimization of voltage and current density.
Mr. Hossein Minouei, Dr. Mohammadhossein Fathi, Dr. Mahmood Meratian, Mr. Hossein Ghazvinizadeh,
Volume 9, Issue 3 (9-2012)
Abstract

ASTM F-75 Cobalt-base alloy castings are widely used for manufacturing orthopedic implants. This alloy needs both homogenization and solutionizing heat treatment after casting, as well as bioactivation of the surface to increase the ability of tissue bonding. In this study, ASTM F-75 Cobalt-base substrate was heat treated at 1220°C for 1 hour in contact with Hydroxyapatite-Bioglass powder in order to solutionize and homogenize the microstructure and promote surface bioactivation. For bioactivity evaluation, heat treated specimens were immersed in Simulated Body Fluid (SBF). Surface of specimens before and after the immersion was analyzed by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDX) and X-Ray Diffraction (XRD). Results showed an appropriate microstructure with bioactive layer on the surface of specimens after heat treatment. In vitro result and formation of bone-like apatite layer on specimens indicated that heat treated samples were potentially suitable for bone replacement and tissue regeneration under highly loaded conditions.
N. Yazdani, J. Javadpour, B. Eftekhari Yekta, M. Hamrang,
Volume 16, Issue 1 (3-2019)
Abstract

This study focuses on the physical, magnetic, biological and antibacterial behaviour of cobalt-doped HAp powder samples. Pure and Cobalt- doped HAp nanoparticles were synthesized by hydrothermal method. Calcium nitrate, di- ammonium hydrogen phosphate and cobalt nitrate were used as precursor materials.  The synthesized powders were characterized using x-ray diffraction pattern (XRD), fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), vibrating sample magnetometer (VSM), Raman spectroscopy as well as MTT assay and cell adhesion test. Disc diffusion method was used to investigate antibacterial activity of the samples. The results confirmed the substitution of Ca by Co ions in the HAp lattice. In addition, this substitution induced size reduction and morphology change in HAp particles. All cobalt substituted HAp powder samples displayed paramagnetic properties, as opposed to the diamagnetic behaviour observed in the pure HAp samples. In addition, these nanoparticles exhibited cell adhesion, biocompatibility and antibacterial activity against S.aureus bacteria.
This study focuses on the physical, magnetic, biological and antibacterial behaviour of cobalt-doped HAp powder samples. Pure and Cobalt- doped HAp nanoparticles were synthesized by hydrothermal method. Calcium nitrate, di- ammonium hydrogen phosphate and cobalt nitrate were used as precursor materials.  The synthesized powders were characterized using x-ray diffraction pattern (XRD), fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), vibrating sample magnetometer (VSM), Raman spectroscopy as well as MTT assay and cell adhesion test. Disc diffusion method was used to investigate antibacterial activity of the samples. The results confirmed the substitution of Ca by Co ions in the HAp lattice. In addition, this substitution induced size reduction and morphology change in HAp particles. All cobalt substituted HAp powder samples displayed paramagnetic properties, as opposed to the diamagnetic behaviour observed in the pure HAp samples. In addition, these nanoparticles exhibited cell adhesion, biocompatibility and antibacterial activity against S.aureus bacteria.
Chimmachandiran Suresh Kumar, Kaliyan Dhanaraj, Ramasamy Mariappan Vimalathithan, Perumal Ilaiyaraja, Govindhasamy Suresh,
Volume 18, Issue 1 (3-2021)
Abstract

The Nano Hydroxyapatite (HAp), HAp/PEG and HAp/PVP powders derived from both Gastropod shell (natural source) and chemical precursor by the precipitation method were characterized through various characterization techniques such as FT-IR, XRD, SEM-EDX, TEM, Antibacterial activity and SBF analysis. Based on the structural, chemical, morphological and biological characteristics, HAp/PVP from natural and chemical precursors have been compared successfully. Calculated structural parameters, crystallinity index, C/P ratio, morphology, antibacterial activity and SBF analysis of the products show that HAp/PVP-S (derived from a natural source) exhibits good mechanical property, rod like morphology, good antibacterial activity and apatite formation ability at 14 days. EDX analysis also shows the presence of carbon and sodium in HAp/PVP-S. Comparative analysis reveals that characteristics of HAp/PVP-S such as high carbonate content, low crystallite size, poor crystalline nature, presence of trace metal, non-stoichiometric elemental composition and rod like crystals which are matched with the characteristics of biological apatite. Thus, the HAp/PVP-S has the ability to form bone apatite.
Seyedali Seyedmajidi, Maryam Seyedmajidi,
Volume 19, Issue 2 (6-2022)
Abstract

Recently, using calcium phosphates and at the top of them, hydroxyapatite (HA) has been considered in medical and dental applications as an artificial biomaterial due to their chemical and structural similarity to the bodychr('39')s skeletal tissues such as bone and tooth. Because of reinforcement of hydroxyapatitechr('39')s mechanical and biological properties by substitution of OH- groups by F- ions to produce fluorapaptite (FA) has been proven, in this article synthesis methods, properties and medical applications of fluorapatite and its pros and cons in comparison with hydroxyapatite have been reviewed.
Silvana Artioli Schellini, Lucieni Cristina Barbarini Ferraz, Abbas Rahdar, Francesco Baino,
Volume 19, Issue 2 (6-2022)
Abstract

Biocompatible ceramics, commonly known as “bioceramics”, are an extremely versatile class of materials with a wide range of applications in modern medicine. Given the inorganic nature and physico-mechanical properties of most bioceramics, which are relatively close to the mineral phase of bone, orthopedics and dentistry are the preferred areas of usage for such biomaterials. Another clinical field where bioceramics play an important role is oculo-orbital surgery, a highly cross- and interdisciplinary medical specialty addressing to the management of injured eye orbit, with particular focus on the repair of orbital bone fractures and/or the placement of orbital implants following removal of a diseased eye. In the latter case, orbital implants are not intended for bone repair but, being placed inside the ocular cavity, have to be biointegrated in soft ocular tissues. This article reviews the state of the art of currently-used bioceramics in orbital surgery, highlighting the current limitations and the promises for the future in this field.
Farnaz Dehghani Firoozabadi, Ahmad Ramazani Saadatabadi, Azadeh Asefnejad,
Volume 19, Issue 2 (6-2022)
Abstract

Fabrication of fully optimized tissue-engineered materials in order to simulating the natural structure, and enhancing the biological properties of damaged tissue is one of the major challenges in biomedical engineering and regeneration medicine. Although polymeric based membranes have revealed noticeable advancements in bone regeneration, their mechanical stiffens, electrical conductivity and bioactivity need to be tolerated.
 Therefore, the present study is designed to generate a multifunctional biomaterial based on polylactic acid (PLA)/ polycaprolactone (PCL)/hydroxyapatite (HA) nanocomposite containing zinc oxide (ZnO) and Graphene (Gr) nanoparticles employing solvent casting combined with die cast techniques for using as absorbable joint implants in bone tissue regeneration. The physical, chemical, mechanical and biological properties of the produced nanocomposite biomaterials were analyzed in vitro. A detailed experimental evaluation between the nanocomposite coatings was carried out to shed light on the effect of ZnO and Gr nanoparticles on the properties.
It was found that the nanocomposite contained 1% ZnO and 1% graphene with a Young's modulus of 1540.5 ± 169.426MPa and the pure sample had a Young's modulus of 1194.81±215.342MPa. The rate of elongation at break of the nanostructure contained 1% graphene was 5.1±0.816%. This value was 3.8±0.944% for the pure sample. The improvement in elongation at break is due to the presence of polycaprolactone in the polymer matrix. The optimal sample with 1% zinc oxide and 1% graphene had antibacterial properties more than other samples. Also, the survival rate of fibroblasts cell in the vicinity of the optimal matrix was significantly different from other samples.
The obtained results revealed that the incorporation of the nanoparticles improved physico-chemical features and mechanical strength with enhanced biological properties and its anti-bacterial performance makes this material a promising candidate for further bone regeneration studies.
 


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