Sharif Digital Repository

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... 

Successful treatment of bone infections is a major orthopedic challenge due to the physiological and anatomical features of bone. In this project, we prepared a drug delivery system with injectable and biodegradable polysaccharide agar containing alginate, polyvinyl alcohol and hydroxyapatite nanocarriers composite microspheres. Alginate and polyvinyl alcohol composite microspheres are crosslinked by calcium and freeze-thawing technique. Using the freeze thawing process for polyvinyl alcohol crosslinking, in addition to alginate crosslinking, improved hydrogel swelling behavior and enhanced drug loading and thus slowed drug release, drug loading increased with increasing PVA percentage from ... 

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... 

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... 

Magnesium is one of most important elements in bio hedroxyapatite. Magnesium effects on all stages of bone growth metabolism. Also increases bone’s osteoblastic and osteoclastic activities. That’s why incorporation of Mg ions into hudroxyapatite structure has become one of interesting fields for bone implants production. In addition Mg can improve sintering and mechanical properties of HAp. Thet’s why in this investigation the effect of incorporated Mg into HAp structure has been studied. Three kinds of powders have been prepared to perform this study. Pure HAp nano powder produced via sol-gel method, Mg contain HAp nano powder produced via sol-gel method and a mixture of nano HAp and nano... 

In this project ,it has been done different surface treatment on 6 samples of nitinol with 40 % prosity,three of them are anodized by H2SO4 ,Hf, Acetic acid, one of them is treated with plasma spray with TIO2 powder, one of them is putted in the furnace at 700 degrees for an hour, and the last one is bare ; Moreover, these treated samples are putted in Simulated body fluid for 16 days . After this period of time, we analyzed the results. Then the cell adhesion amount of osteo blast cells (MG 63) is measured to these samples by immersing them for 3 days in these cells.The results are investigated by SEM ,XRD(X pertpro produced by Panalitical), XRF(530-XRF-01), AAS( AA240), Roughness measuring... 

Magnesium and its alloys are biodegradable materials with mechanical properties similar to the bone tissue, therefore these materials are suitable for producing orthopedic implants. Unfortunately Magnesium and its alloys are corroded too fast in physiological environment which is the main obstacle for usage of these materials as orthopedic implants. Producing Hydroxyapatite(HA) coatings on surface of Magnesium and its alloys is one of the popular and useful methods for reducing the corrosion rate in physiological environment. HA is a biocompatible and bioactive coating with the ability to bond chemically with the bone tissue and therefore it is largely used as a bioactive coating on the... 

In this research, role of zirconia nanoparticles as a biocompatible material which has great mechanical properties, was investigated on corrosion behavior and bonding strength of HA coating. HA- ZrO2 composite prepared by a 2-step pulse electrodeposition method. Effect of pH (3.5, 4.5), bath temperature (60, 80 ͦC), current density (0.5, 1, 2 mA/cm2) and zirconia concentration (5, 10, 15 g/L) on coating characteristics were studied. X-ray diffraction was employed for phase analysis. Morphology and microstructure of samples observed utilizing scanning electron microscope (SEM) and elemental analysis was done by EDS. In order to corrosion studies electrochemical impedance spectroscopy (EIS)... 

The main purpose of this research is design and manufacture of nanostructured hydroxyapatite-coated foamy core@compact shell Ti-6Al-4V bone-like composites for utilization as substitutive implant for cortical bone having porous core. The production procedure consist of two steps; (a) fabrication of foamy core@compact shell Ti-6Al-4V alloy using powder metallurgy-space holder technique, (b) precipitation of hydroxyapatite on the Ti-6Al-4V alloy specimens via pulse electrodeposition process. The bone-like structures were designed to reduce the stress shielding which ensures long-term stabilization of implants. It is while that, the hydroxyapatite coating improve the biological response of... 

This investigation presents synthesis and characterization of pure and monophasic hydroxyapatite (Ca10(PO4)6(OH)2; HA) Nanostructures prepared by coral and oyster shell powders heated at 800 oC for 8 h as precursor via precipitation method. The morphology of HA nanostructures was controlled in the presence of various surfactants such as SDS, CTAB and PVP. The HA Nanorods synthesized by SDS were applied to fabricate bone scaffolds. Particle sizes of the HA Nanoparticles were about 20-30 nm. Pours three-dimensional HA/Ge/CMC scaffolds cross-linked by citric and oxalic acids were synthesized. In order to increase the pore size of the scaffolds, NaCl with medium (180-250 µm) and large (420-500... 

This study investigates the effect of titanium dioxide and magnesium oxide additives on hydroxyapatite synthesized by sol-gel and composite with the predominant phase of hydroxyapatite by in situ method to improve mechanical properties. Scaffold samples were synthesized with nanometer-sized hydroxyapatite and composite powder particles by gel casting and sintered at 1200 ° C. Then, to evaluate the synthesized powders, simultaneous thermal analysis (STA), X-ray diffraction test, FTIR test, FESEM, EDS, and MAP analysis were used. Also, to evaluate the mechanical properties of the scaffolds, a compressive test was used, and to evaluate the scaffolds' density, the Archimedes method was used.... 

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... 

This investigation presents synthesis and characterization of pure and monophasic hydroxyapatite (Ca10(PO4)6(OH)2; HA) Nanostructures prepared by coral and oyster shell powders heated at 800 oC for 8 h as precursor via precipitation method. The morphology of HA nanostructures was controlled in the presence of various surfactants such as SDS, CTAB and PVP. The HA Nanorods synthesized by SDS were applied to fabricate bone scaffolds. Particle sizes of the HA Nanoparticles were about 20-30 nm. Pours three-dimensional HA/Ge/CMC scaffolds cross-linked by citric and oxalic acids were synthesized. In order to increase the pore size of the scaffolds, NaCl with medium (180-250 µm) and large (420-500...