Showing 11 results for Hydroxyapatite
M. H. Fathi, Gh. Feizi, Sb. Moosavi, Gh. Gahanshahi, M. Salehi, A. Saatchi and V. Mortazavi,
Volume 20, Issue 1 (7-2001)
Abstract
Hydroxyapatite coatings have been used on metallic substrates in a variety of applications, including modifying the surface of human implants, bone osseointegration and biological fixation. In this paper, the effects of various kinds of metallic substrate on clinical and pathological results of in vivo tests are presented. Four kinds of endodontic implants i.e, stainless steel, cobalt base alloy, plasma sprayed hydroxyapatite coated stainless steel, plasma sprayed hydroxyapatite coated cobalt base alloy were prapared and implanted in mandibular canine of
cats. After a healing period of 4 months, investigation by SEM and histopathological interpretation and evaluation showed significant differences in tissue response and osseointegration between coated and non-coated metallic implants. It was concluded that the results were affected by the kind of metallic substrate .
Keywords: Hydroxyapatite coating, Dental endodontic implant, Osseointegration, Corrosion, Stainless steel,
Cobalt base alloy
B. Mostaghaci, M. H. Fathi, M. Sheikh-Zeinoddin, and S. Soleimanianzad,
Volume 27, Issue 2 (1-2009)
Abstract
S. Salehi, M. H. Fathi, K. Raeissi,
Volume 29, Issue 1 (6-2010)
Abstract
The addition of ZrO2 particles to the HA coating has received considerable attention because ZrO2 particles increase the bonding strength between HA coating and substrate. In this study, nanostructured hydroxyapatite (HA)/yttria stabilized zirconia (YSZ) coatings were prepared by a sol–gel method. It was found that at 950ºC, the dominant phases were HA and tetragonal (t)-zirconia in 3YSZ, cubic (c)-zirconia in 8 YSZ and t-c-Zirconia in 5YSZ phases with the small amounts of β-tricalcium phosphate (β-TCP) and CaZrO3. The crystallite size of the coating was about ~20-30 nm for tetragonal and cubic zirconia grain size and 40-80 nm for hydroxyapatite grain size. Crack-free and homogeneous HA/YSZ composite coatings were obtained with no observable defects. In vitro evaluation in 0.9% NaCl showed that Ca2+ dissolution rate of composite coatings was lower than that of pure HA coatings. The decrease in electrochemical performance of these coated samples in comparison with the uncoated type 316L St.St could be associated with chloride ion and water penetration into the coating, transport of ions through the coating, and the subsequent electrochemical reactions at the coating–metal interface.
M.h. Fathi, A. Hanifi, S.i. Roohani Esfahani,
Volume 30, Issue 2 (12-2011)
Abstract
Due to its biocompatibility, bioactivity and high durability properties, hydroxyapatite (HA) has a wide range of applications in medical cases such as bone defect treatment and bone tissue regeneration. Biological apatite as the most important integrity of the mineral part of hard tissues consists of tiny hydroxyapatite crystals in nanoregime. It seems that using the artificial hydroxyapatite with similar structure and chemical composition to biological apatite could increase its durability inside the natural hard tissues. The aim of the present work was the synthesis of nano structured hydroxyapatite via different routes, comparison of their characterization and enhancement of the bioactivity and bioresorbability of prepared hydroxyapatite by controlling its crystal size and chemical composition. Nano structured hydroxyapatite was prepared by mechanical activation and sol-gel routes. X-ray diffraction technique (XRD), Fourier transform infra red spectroscopy (FTIR) and transmission electron microscopy (TEM) were used to characterize the prepared hydroxyapatite powders. The synthesized powder was soaked in simulated body fluid (SBF) for various periods of time in order to evaluate its bioresorbability and bioactivity after immersion in SBF. Atomic absorption spectroscopy (AAS) was used to determine the dissolution rate of calcium ions in SBF media. Results showed that the mechanical activation prepared HA powder had nano scale structure with mean size of 29 nm and the sol gel prepared HA powder had nano scale structure with mean size of 25 nm. Ionic dissolution rate of prepared nano structured powders was higher than the conventional HA (with micron size) and were similar to biological apatite. It could be concluded that bioactivity behavior of hydroxyapatite powder is affected by its crystalline size. By using the nano structure HA powder with less than 50 nm crystalline size, the optimum bioactivity and bioresorbability would be achieved.
M. Ashuri, F. Moztarzadeh, N. Nezafati, A. Ansari Hamedani, M. R. Tahriri,
Volume 31, Issue 1 (6-2012)
Abstract
In the present study, a bioceramic-based composite with remarkable mechanical properties and in vitro apatite forming ability was synthesized by sintering compacts made up of mixtures of hydroxyapatite (HA) and sol-gel derived bioactive glass (64SiO2-26CaO-5MgO-5ZnO) (based on mole %). HA was synthesized through co-precipitation method. The stabilization temperature of the bioactive glass was set to be 700 ºC according to simultaneous thermal analysis (STA). Laser Particle Size Analysis (LPSA) was used to compare the particle size distributions of the synthetic powders. HA matrix was mixed with different weight percentages of bioactive glass (5, 10, 15, 20, 25 and 30 wt. %) and compressed by 80 MPa pressure. After sintering the uniaxial compression test of the samples was done and the specimen with the highest compressive strength (20 wt. % bioactive glass) was selected to be immersed in the Simulated Body Fluid (SBF) for 3, 7 and 14 days. The results showed that the compressive strength of the sample decreased after keeping it in the SBF. Also, inductively coupled plasma analysis (ICP) was used to study the ion release behavior of the sample in the SBF. Finally, phase composition, microstructure and functional groups in the composite were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infra-red spectroscopy (FTIR) techniques, respectively.
M. Mazrooei Sebdani, M. H. Fathi ,
Volume 31, Issue 2 (12-2012)
Abstract
Despite excellent bioactivity of bioactive ceramics such as hydroxyapatite, their clinical applications have been limited due to their poor mechanical properties. Using composite coatings with improved mechanical properties could be a solution to this problem. Therefore, the strength of metal substrate and the bioactivity of the improved composite coating combined could yield suitable results. The aim of this work was fabrication and characterization of hydroxyapatite-forsterite-bioactive glass nanocomposite coating. The sol-gel technique was used to prepare hydroxyapatite-forsterite-bioactive glass nanocomposite in order to coat on 316L stainless steel (SS) by deep coating technique. The X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and energy dispersive X-ray analysis (EDX) techniques were used to investigate the microstructure and morphology of the prepared coating. The results obtained from XRD analysis showed that the suitable temperature for calcination is 600 °C. At this temperature, the homogenous and crack-free coating could attach to the 316L SS substrate. The crystallite size of composite coatings determined via AFM was lower than 100 nm. Overall, the results obtained from this work indicate that hydroxyapatite-forsterite-bioactive glass nanocomposite coating can be a good candidate for biomedical applications.
M. Shamsi, N. Nezafati, S. Zavareh, A. Zamanian,
Volume 35, Issue 1 (6-2016)
Abstract
Ternary (%mol) (64SiO2-31CaO-5P2O5) system of sol-gel derived bioactive glass fibers was prepared by electrospinning method. X-ray Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and nitrogen adsorption test (BET) analyses were performed to investigate the phase and chemical group of the composition, morphology of the surface and specific surface area of the fibers, respectively. SEM observations confirmed that the fibers were nano size. The amorphous nature and the presence of silanol groups in the composition were confirmed by XRD and FTIR, respectively. Apatite formation and biodegradability of the fibers were studied using various analyses after different days of soaking in simulated body fluid (SBF). The results affirmed the presence of apatite layers on the surface of the fibers. Cell culture evaluation indicated that MG-64 human osteoblast-like cells were attached and spread well on the surface. Furthermore, cell viability and cell growth demonstrated that the cells were grown and reproduced well on the fibers.
M. Kouhi, M. Shamanian, M. Fathi, Molamma Prabhakaran, Seeram Ramakrishna,
Volume 36, Issue 3 (11-2017)
Abstract
In this work, poly (hydroxybutyrate co hydroxyvalerate) (PHBV) composite nanofibrous scaffold containing hydroxyapatite/bredigite (HABR) nanoparticles was fabricated through electrospining method. The morphology of prepared nanofibers and the state of the nanoparticles dispersion in nanofiber matrix were investigated using scanning and transmission electron microscopy, respectively. Evaluation of the mechanical properties of the nanofibrous scaffolds revealed that there is a limit to the nanoparticle concentration at which nanoparticles can improve the mechanical properties of the nanofibrous scaffolds. According to the results, PHBV/HABR nanofibers showed higher wettability compared to PHBV nanofibers. In vitro cell culture assay was done using human fetal osteoblast cells on nanofibrous scaffold. MTS assay revealed that cell proliferation on the composite nanofibrous scaffold was significantly higher than those on the pure scaffold after 10 and 15 days. Scanning electron microscopy- Energy dispersive X-ray spectroscopy and CMFDA colorimeter assay analysis showed that the cells on the PHBV/HABR scaffolds acquired higher mineral deposition than the cells on the pure PHBV and control sample scaffold. Based on the results we concluded that PHBV/HABR nanofibers scaffold with higher wettability, improved mechanical properties and cell behavior hold great potential in bone regeneration applications.
M. Mirhaj, M. Mahmoodi, A. Shybani,
Volume 36, Issue 4 (3-2018)
Abstract
In this research, keratin (Kr)/ poly caprolactone (PCL)/ hydroxyapatite (HA) scaffold was made by electrospinning method. Then, the effect of HA nanoparticles on properties of scaffold B (Kr 33%, PCL 50% and HA 17%) and scaffold A (Kr 40% and PCL 60%) were studied. The surface morphology, functional groups on the surface of samples, porosity, and specific surface area were evaluated by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectrophotometer (FTIR), liquid displacement method, and BET test, respectively. The mean diameter of fibers in samples A and B was measured 184 nm and 108 nm, respectively. Results showed that the specific surface area in scaffolds with HA nanoparticles was almost 2 times higher than that of the scaffold without HA. The biodegradability of scaffolds was examined in phosphate buffer solution (PBS) and the results showed an increase in the weight loss percentage of the scaffold B. The cell viability and adherence of osteosarcoma cell line (Saos-2) on the scaffold surface was observed via MTT assay and the results showed an increase in cell growth on PCL/Kr scaffolds with HA nanoparticles. Thus, scaffolds containing HA nanoparticles can be a good choice for tissue engineering applications.
F. Fareghdeli, M. Karimi, A. Novin, M. Solati-Hashjin,
Volume 40, Issue 3 (11-2021)
Abstract
One challenge in preparing polymer/ceramic composites is non-uniform ceramic particles distribution in a polymer matrix. This research evaluated the effect of stirring time and temperature on hydroxyapatite (HA) distribution through (polylactic acid) PLA matrix. Therefore, to mix the ceramic suspension with the polymer solution, three temperatures, namely 25, 37, and 45°C and four times including 6, 12, 24 and, 48 h were examined. Fourier-transform infrared spectroscopy (FTIR) analysis was used to investigate the bonds, which showed physical bond formation such as carboxyl-calcium-carboxyl between HA and polymer matrix, influenced on particles distribution. Scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS) were used to observe particles distribution and determine samples homogeneity. To fulfill this goal, each obtained photograph representing the calcium presentation was split into nine equal sections, and a method based on the newly defined index called dispersion factor “α” was used to analyze the distribution. Results showed that the sample prepared at 37°C and 48 h had the topmost homogeneity properties.
F. Dehghani Firoozabadi, A. Ramazani Saadatabadi, A. Asefnejad,
Volume 41, Issue 1 (8-2022)
Abstract
Today, many people need to use bone grafts and implants because of damage to bone tissue. Due to the stimulation of the immune system after implantation, infection at the operation site is very common, which causes swelling and pain in the operation area. The use of zinc oxide nanoparticles reduces infection at the operation site and reduces the patient's need for antibiotics. In the present study, the morphology of the scaffolds was investigated by field emission scanning electron microscope (FE-SEM). The toxicity of the samples was evaluated using MTT assay. The behavior of nanocomposites against Escherichia coli and Staphylococcus aureus was investigated by measuring the diameter of the growth inhibition zone. It was found that modification of scaffolds with nanoparticles caused a growth inhibition in bacterial culture medium. It was also observed that fibroblast cells on the surface of the modified scaffolds had longer survival than polymer scaffolds. This study showed that the addition of oxidizing nanoparticles improves the antibacterial properties of scaffolds and cell viability and reduces scaffold toxicity.
