Loading...
Search for:
hydroxyapatite
0.008 seconds
Total 117 records
Human serum protein adsorption onto synthesis nano-hydroxyapatite
, Article Protein Journal ; Volume 31, Issue 2 , February , 2012 , Pages 150-157 ; 15723887 (ISSN) ; Massah Bidgoli, M ; Behrashi, M ; Mohsen Nia, A ; Sharif University of Technology
Abstract
Adsorption of human serum proteins (Albumin and total protein) onto high purity synthesis nano-hydroxyapatite (HA), Ca 10(PO 4) 6(OH) 2, has been studied in a wide temperature range by UV-visible spectrophotometer. Adsorption isotherm is basically important to describe how solutes interact with adsorbent, andiscriticalinoptimizing the use of adsorbent. Inthe present study, the experimental results werefitted tothe Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (DR) models to obtain the characteristic parameters of each model and square of the correlation coefficients (R 2). According to the results, the DR isotherm model had the best agreement with the experimental data. The effect of...
Milling media effects on synthesis, morphology and structural characteristics of single crystal hydroxyapatite nanoparticles
, Article Advances in Applied Ceramics ; Volume 109, Issue 2 , 2010 , Pages 117-122 ; 17436753 (ISSN) ; Honarmandi, P ; Shokuhfar, A ; Nasiri Tabrizi, B ; Ebrahimi Kahrizsangi, R ; Sharif University of Technology
2010
Abstract
This paper presents a dry mechanochemical process to produce hydroxyapatite (HAp) nanoparticles. Two distinct chemical reactions are introduced to prepare HAp powders using milling process. Structural and morphological properties of the obtained materials are studied by X-ray diffraction and transmission electron microscopy. The results reveal that the single crystal HAp nanoparticles have been successfully produced in metallic and polymeric vials through two different experimental procedures. Tempered chrome steel and polyamide-6 materials are adopted as the metallic and polymeric vials respectively. Nanoellipse, nanorod and nanosphere powders are obtained in these experimental procedures....
Characterization of sol-gel derived silver/fluor-hydroxyapatite composite coatings on titanium substrate
, Article Surface and Coatings Technology ; Volume 352 , 2018 , Pages 522-528 ; 02578972 (ISSN) ; Abbasi Khazaei, B ; Afshar, A ; Sharif University of Technology
Elsevier B.V
2018
Abstract
A composite coating containing silver, fluoride and hydroxyapatite (Ag-FHA) was developed on titanium substrate by sol-gel method. Triethylphosphite, hydrated calcium nitrate, ammonium fluoride and silver nitrate were used respectively, as P, Ca, F and Ag precursors with a Ca:P ratio 1.67 and concentration of silver was 0.3 wt%. Coatings were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and atomic absorption spectrometry (AAS). Potentiodynamic polarization measurements in simulated body fluid proved corrosion protection caused by both Ag-FHA coatings. Antibacterial activity of coatings against...
Fabrication and characterization of a starch-based nanocomposite scaffold with highly porous and gradient structure for bone tissue engineering
, Article Biomedical Physics and Engineering Express ; Volume 4, Issue 5 , 2018 ; 20571976 (ISSN) ; Eslamian, M ; Bagheri, R ; Sharif University of Technology
Institute of Physics Publishing
2018
Abstract
Starch based scaffolds are considered as promising biomaterials for bone tissue engineering. In this study, a highly porous starch/polyvinyl alcohol (PVA) based nanocomposite scaffold with a gradient pore structure was made by incorporating different bio-additives, including citric acid, cellulose nanofibers, and hydroxyapatite (HA) nanoparticles. The scaffold was prepared by employing unidirectional and cryogenic freeze-casting and subsequently freeze-drying methods. Fourier transform infrared (FTIR) spectroscopy confirmed the cross-linking of starch and PVA molecules through multiple esterification phenomenon in the presence of citric acid as a cross-linking agent. Field emission scanning...
Inclusion of carbon nanotubes in a hydroxyapatite sol-gel matrix
, Article Ceramics International ; Volume 35, Issue 7 , 2009 , Pages 2987-2991 ; 02728842 (ISSN) ; Nemati, Z. A ; Sadeghian, Z ; Sharif University of Technology
2009
Abstract
In this study, the inclusion of multi-walled carbon nanotubes as the second phase in the hydroxyapatite matrix, in order to improve the mechanical strength, has been performed via the sol-gel process. The stability of carbon nanotube sol with the changes of pH and dispersant values (sodium dodecyl sulfate) was evaluated by zeta potential analysis. The results indicated that synthesis of hydroxyapatite particles in the presence of the carbon nanotubes had the best result in homogenization of the carbon nanotube dispersion and faster crystallization of hydroxyapatite. The crystallization of hydroxyapatite phase was investigated with differential scanning calorimetry (DSC) and X-ray diffraction...
Optimization of nano HA-SiC coating on AISI 316L medical grade stainless steel via electrophoretic deposition
, Article Materials Letters ; Volume 285 , 2021 ; 0167577X (ISSN) ; Ahangari, M ; Johar, M. H ; Allahkaram, S. R ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Biocompatible nanostructured coating plays an important role in enhancement of osseointegration ability of metallic implants. This study sets out to obtain optimized SiC concentration in Hydroxyapatite (HA) coating on AISI 316L stainless steel alloy through electrophoretic deposition method. Effect of SiC concentrations (1, 2, and 3%.wt) on the morphology, corrosion behaviour, and mechanical properties of the HA coating is investigated. Results show that SiC could obstruct the formation and growth of micro cracks in the HA coating where HA-3%SiC is considered as a crack free coating. Electrochemical tests reveal that SiC has improved the corrosion resistance of HA coating, and HA-3%SiC...
Fabrication and Characterization of Nanocomposite Bone Scaffold with Gradient Structure Based on Thermoplastic Starch
, M.Sc. Thesis Sharif University of Technology ; Bagheri, Reza (Supervisor)
Abstract
Tissue regeneration by bio-compatible/degradable scaffolds is one of the widely used approaches in the field of tissue engineering. In this study, a thermoplastic starch based nanocomposite scaffold with gradient structure was fabricated by unidirectional freeze drying method. To increase the stability of the scaffold in the aqueous media, PVA was added to starch solution. Then, the PVA and starch molecules were cross-linked by adding citric acid to the mixture. On the one hand, to improve the mechanical properties of the scaffold, and control its bio-degradability on the other, cellulose nano-fibers were employed. Also, the bioactivity of the scaffold was induced by using hydroxyapatite...
Studying the Effect of Zirconia & GNP on Mechanical, Tribological & Biological Properties of UHMWPE-HAp Nanocomposites used in Total Hip Joint Replacement
, M.Sc. Thesis Sharif University of Technology ; Bagheri, Reza (Supervisor) ; Faghihi Sani, Mohammad Ali (Supervisor)
Abstract
Medical engineering advances in total joint replacements and society’s rising demand for long lasting materials, have proven it essential to manufacture materials that are more similar to the original tissue in the fields of mechanical, tribological and biological properties. Ultra High Molecular Weight Polyethylene(UHMWPE), is a polymer widely used in arthroplasty applications due to its biocompatibility, chemical stability and proper mechanical properties. In this study, UHMWPE-HAp nanocomposites reinforced with Zirconia and Graphene were manufactured aiming to reach a structure that is more compatible with bone tissue and also to improve overall properties. First, using ultrasonication...
Synthesis and Characterization of Nano Hydroxyapatite/Acrylated Polyurethane Nanocomposites
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor) ; Abdekhodai, Mohammad Jafar (Supervisor)
Abstract
In the present study, the acrylated polyurethane/nanohydroxyapatite (APU/n-HAp) nanocomposites were fabricated for use in bone tissue regeneration. The APU was synthesized based on poly(ε-caprolactone) diol (PCL), aliphatic 1,6- hexamethylene diisocyanate (HDI) and hydroxyethyl methyl acrylate (HEMA). The effect of HAp nanoparticles on the physicochemical properties of APU was evaluated. The APU/n-HAp nanocomposites were characterized using X-ray diffraction (XRD), dynamic mechanical thermal analyses (DMTA), scanning electron microscopy (SEM) and mechanical tests including tensile strength and elongation at break. The increase in physical properties achieved by incorporation of n-HAp...
Formulation and Investigation of Thermal Behavior and Flexural Properties of PMMA Denture base Reinforced with Modified Nanoparticles m-HAP and m-MWCNTs
, M.Sc. Thesis Sharif University of Technology ; Nemati, Ali (Supervisor) ; Malek Khachatourian, Adrineh (Supervisor)
Abstract
This study investigates the effect of adding hydroxyapatite nanoparticles and multi-walled carbon nanotubes in pure and modified form on the flexural properties and hardness of denture base Polymethyl Methacrylate. Polymethyl Methacrylate (PMMA) is still the most common denture base material. In fact, the mechanical properties of this resin have played a significant role in expanding its use in dentistry. But in the long-term use of resins, defects such as low resistance to crack growth, low flexural strength and brittleness can be seen. In fact, flexural fatigue occurs as a result of repeated flexural stresses, and it can be described as the main reason for crack growth and propagation in...
Synthesis of One-Dimensional Nanoneedle-Like Arrays Hydroxyapatite for Bone Tissue Engineering Applications
, M.Sc. Thesis Sharif University of Technology ; Nemati, Ali (Supervisor) ; Khachatourian, Adrine Malek (Supervisor) ; Shokri, Babak (Co-Supervisor)
Abstract
Implant primary stability is a crucial component of implant survival. Primary mechanical stability is correlated with implant type, surgical technique, quantity and quality of bone at the recipient site. Since bone integration (BI) significance has been acknowledged, a variety of techniques have been developed to quicken BI and achieve faster fixation. Studies have shown that material type, and many surface properties, including as surface composition, roughness, topography, and energy, have a significant influence during the early stages of bone integration to the implant. In this work, we did synthesis one-dimensional nanoneedle-like arrays of hydroxyapatite using the injection method...
PLA/PEG/HAp Nano-Composites as Drug Carriers
, M.Sc. Thesis Sharif University of Technology ; Frounchi, Masoud (Supervisor)
Abstract
In recent years, the tendency to use biodegradable and biocompatible polymer nanoparticles for drug delivery applications has been increasing, the reason for this being the possibility of precise control of the drug release rate, ease of use, and no need for external Surgery after the release of the drug, increases the therapeutic efficiency of the drug and reduces the side effects with its precise transfer. In this research work, drug carrier nanocomposites were prepared from polylactic acid (PLA), polyethylene glycol (PEG) and hydroxyapatite (HAp) and for the controlled release of ciprofloxacin (CIP). It was used to treat bone infections. The drug loading efficiency for nano-carriers was...
Preparation of HA/Al2O3/MgO Biocompatible Nanocomposite Coating by Electrophoretic Method on 316 Stainless Steel
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor)
Abstract
In this research, it has been tried to use alumina and magnesia nanoparticles to hydroxyapatite nano powder, a three-component coating, with corrosion resistance, adhesion and desirable biocompatibility on the 316 stainless steel substrate, by electrophoretic method. It should be applied at 3 voltages of 10, 30 and 50 volts and for 3 minutes. TEA was used as a dispersing agent and ethanol as a solvent to prepare the suspension. Alumina nano powder was added to nanohydroxyapat in two amounts of 10 and 20% by weight and 20% was optimized as the amount, and magnesia nano powder was added to the composition in three amounts of 1, 3 and 5% by weight, which was 3% by weight of the results Was...
Na Alginate/PVP/Hap nano-composites Hydrogels
, M.Sc. Thesis Sharif University of Technology ; Frounchi, Masoud (Supervisor)
Abstract
In this research, we developed a drug release system of two biocompatible and biodegradable polymers and biocompatible ceramic nanoparticles. Hydrogels of sodium alginate (SA) were crosslinked using calcium chloride. The SA hydrogels were blended with polyvinyl pyrrolidone (PVP) and mixed with hydroxyapatite nanoparticles (HAP) to make hydrogel nanocomposites in the form of microbeads as drug carriers. Ciprofloxacin was selected as a model antibiotic drug for treatment of bone infection. It was found that SA and PVP form hydrogen bonds and are miscible at whole range of concentrations. Indeed, the SA/PVP blends may be considered as interpenetrating polymer networks (IPNs). HAP nanoparticles...
MAO-derived hydroxyapatite/TiO 2 nanostructured multi-layer coatings on titanium substrate
, Article Applied Surface Science ; Volume 261 , 2012 , Pages 37-42 ; 01694332 (ISSN) ; Golestani Fard, F ; Rezaie, H. R ; Mirhosseini, S. M. M ; Sharif University of Technology
2012
Abstract
In this study, titanium substrates which previously oxidized through Micro arc oxidation method, was coated by Hydroxyapatite (HAp) coating once more by means of the same method. Morphology, topography and chemical properties as well as phase composition and thickness of layers were studied to reveal the effect of the electrolyte concentration on coating features. According to results, the obtained coatings are consisted of HAp and titania as the major phases along with minor amounts of calcium titanate and α-tri calcium phosphate. Ca and P are present on surface of obtained layers as well as predictable Ti and O based on the XPS results. Thickness profile of coatings figured out that by...
Nano-crystalline growth of electrochemically deposited apatite coating on pure titanium
, Article Journal of Electroanalytical Chemistry ; Volume 589, Issue 1 , 2006 , Pages 96-105 ; 15726657 (ISSN) ; Afshar, A ; Yang, X ; Li, X ; Yang, B ; Wu, Y ; Chen, J ; Zhang, X ; Sharif University of Technology
Elsevier
2006
Abstract
Hydroxyapatite (HA) coatings were deposited on commercially pure titanium plates using a hydrothermal-electrochemical deposition method in an electrolyte containing calcium and phosphate ions. The deposition conditions used in this study were the followings: electrolyte temperature (33-80 °C), current density (1-8 mA/cm2), and deposition time (10-120 min). Needle-like and granular crystals of apatite coating were created with different concentrations of calcium (0.0021-0.042 M) and phosphate (0.00125-0.025 M) salts. The size of HA crystals of the coating was considerably changed with different concentration of calcium and phosphate salts, temperature of the electrolyte, and deposition time....
Supramolecular polycaprolactone nanocomposite based on functionalized hydroxyapatite
, Article Journal of Bioactive and Compatible Polymers ; Volume 27, Issue 5 , January , 2012 , Pages 467-480 ; 08839115 (ISSN) ; Shokrollahi, P ; Atai, M ; Omidian, H ; Bagheri, R ; Sharif University of Technology
SAGE
2012
Abstract
Arms bearing ureido-pyrimidinone functional groups with self-association capability (through quadruple hydrogen bonds) were successfully grafted onto hydroxyapatite nanoparticles. The supramolecularly modified nanoparticles (nHApUPy) exhibited enhanced colloidal stability compared to the original hydroxyapatite nanoparticles and were uniformly dispersed in supramolecular polycaprolactone in PCL(UPy)2/HApUPy nanocomposites at different filler loadings. The combined atomic force microscopy, mechanical, and rheological analyses confirmed a high degree of compatibility of HApUPy nanoparticles with the polymer matrix. The temperature dependence of the supramolecular structure in PCL(UPy)2/HApUPy...
In vitro study: Bond strength, electrochemical and biocompatibility evaluations of TiO2/Al2O3 reinforced hydroxyapatite sol–gel coatings on 316L SS
, Article Surface and Coatings Technology ; Volume 405 , 2021 ; 02578972 (ISSN) ; Afshar, A ; Sharif University of Technology
Elsevier B.V
2021
Abstract
To improve the biocompatibility and corrosion resistance of 316L SS (Stainless Steel) metal implants, HAp(hydroxyapatite)/TiO2/Al2O3 nanocomposite coating was created using dip sol-gel method sintered at 550 °C. The weight percentage of TiO2+ Al2O3 in these coatings was 20, 30, and 40% wt. In this study, characterization was performed using FTIR (Fourier-Transform Infrared Spectroscopy), XRD, FE-SEM (Field Emission Scanning Electron Microscope), EDS (Energy Dispersive Spectroscopy), DLS (Dynamic Light Scattering), Pull-off, and AFM (Atomic Force Microscopy) analysis. The potentiodynamic polarization and EIS (Electrochemical Impedance Spectroscopy) were performed in the simulated body fluid...
In vitro study: Bond strength, electrochemical and biocompatibility evaluations of TiO2/Al2O3 reinforced hydroxyapatite sol–gel coatings on 316L SS
, Article Surface and Coatings Technology ; Volume 405 , 2021 ; 02578972 (ISSN) ; Afshar, A ; Sharif University of Technology
Elsevier B.V
2021
Abstract
To improve the biocompatibility and corrosion resistance of 316L SS (Stainless Steel) metal implants, HAp(hydroxyapatite)/TiO2/Al2O3 nanocomposite coating was created using dip sol-gel method sintered at 550 °C. The weight percentage of TiO2+ Al2O3 in these coatings was 20, 30, and 40% wt. In this study, characterization was performed using FTIR (Fourier-Transform Infrared Spectroscopy), XRD, FE-SEM (Field Emission Scanning Electron Microscope), EDS (Energy Dispersive Spectroscopy), DLS (Dynamic Light Scattering), Pull-off, and AFM (Atomic Force Microscopy) analysis. The potentiodynamic polarization and EIS (Electrochemical Impedance Spectroscopy) were performed in the simulated body fluid...
Enhancing glass ionomer cement features by using the HA/YSZ nanocomposite: A feed forward neural network modelling
, Article Journal of the Mechanical Behavior of Biomedical Materials ; Vol. 29 , January , 2014 , pp. 317-327 ; ISSN: 17516161 ; Salehi, S ; Nemati, A ; Tavakoli, R ; Solati Hashjin, M ; Sharif University of Technology
Abstract
Despite brilliant properties of glass ionomer cement (GIC), its weak mechanical property poses an obstacle for its use in medical applications. The present research aims to formulate hydroxyapatite/yttria-stabilized zirconia (HA/YSZ) in the composition of GIC to enhance mechanical properties and to improve fluoride release of GIC. HA/YSZ was synthesized via a sol-gel method and characterized by applying X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photo-emission spectroscopy (XPS) and simultaneous thermal analysis (STA) along with transmission electron microscopy (TEM) methods. The synthesized nanocomposite was mixed with GIC at a fixed composition of 5....