- Associate Professor of Biomedical Engineering (Biomaterials), PhDedit
The feasibility of incorporating high (M/M+Ca = 16 mol. %) and low (M/M+Ca = 4.76 mol. %) concentrations of Mg2+, Zn2+ and Sr2+, as divalent cations with interesting biological properties, into the structure of well-known bioceramic:... more
The feasibility of incorporating high (M/M+Ca = 16 mol. %) and low (M/M+Ca = 4.76 mol. %) concentrations of Mg2+, Zn2+ and Sr2+, as divalent cations with interesting biological properties, into the structure of well-known bioceramic: hydroxyapatite (HA) was carefully assessed. An established hydrothermal synthesis method was employed for preparation of HA in whisker-like morphology. Consequently, the possibility of synthesizing HA whiskers (HAWs) with cationic substitutions and effects of the introduced ions on morphology, structure and composition of HA products were evaluated. Almost, all the cation-substituted preparations could maintain the apatite phase, while the decrease in crystallite size and crystallinity was obvious. Lattice parameters (a, c) of the hexagonal system of HA were also affected in accordance with the type and amount of substituting cation. Zn2+ and high amounts of Mg2+ dramatically inhibited formation of whisker-like apatite and promoted formation of a mixture of hexagonal prism-like and flaky bundles, or hexagonal and multifaceted morphologies, respectively. However, Sr2+ exhibited minimum inhibitory effect on HAWs formation. Therefore, Sr- and Mg-substituted (low concentration of Mg) HAWs could be prepared for their potential biomedical applications.
Injectable composite pastes were prepared using melt‐derived 45S5 bioactive glass and tragacanth crosslinked by (3‐glycidyloxypropyl)trimethoxysilane (GPTMS). The effect of powder to liquid ratio (P:L = 1.0:2.0–1.0:2.5) and... more
Injectable composite pastes were prepared using melt‐derived 45S5 bioactive glass and tragacanth crosslinked by (3‐glycidyloxypropyl)trimethoxysilane (GPTMS). The effect of powder to liquid ratio (P:L = 1.0:2.0–1.0:2.5) and GPTMS/tragacanth ratio (0.0–1.5) on the injectability, swelling behavior, rheology, bioactivity, and cellular behavior of the pastes was investigated. Based on the results, the apparent stability and consistency of the pastes increased upon crosslinking by GPTMS. Due to the increased interactions between tragacanth and glass, a hysteresis loop with larger area was formed in the presence of GPTMS. With increase of GPTMS:tragacanth ratio from 0 to 1.5, the swelling percent dropped from 24.65 to 16.25% after 24 h and the degradation percent also went down from 27.89 to 9.11% after 21 days in the simulated body fluid. The 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay showed a drop in the optical density of MG63 osteoblasts up to 30.07% after exposure to the GPTMS‐crosslinked composite pastes for 3 days. However, the number of viable cells gradually increased in the presence of the pastes and the cell morphology remained unchanged over time. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47604.
Injectable hydrogels and biodegradable nanoparticles are using in tissue engineering applications and drug delivery systems. To improve physiochemical properties of biomaterials and to develop their applications, hybrid systems consist of... more
Injectable hydrogels and biodegradable nanoparticles are using in tissue engineering applications and drug delivery systems. To improve physiochemical properties of biomaterials and to develop their applications, hybrid systems consist of hydrogels, and biodegradable nanoparticles were synthesized. In this study, hybrid systems based on double crosslinked hyaluronic acid and PLGA/Dexamethasone sodium phosphate (PLGADEX) nanoparticles are designed and synthesized in several steps. At the first step, poly(l-lactide-co-glycolide) (PLGA) in a ratio of LLA:GA = 85:15 mol% was synthesized via ring-opening polymerization. Then, PLGADEX nanoparticles were synthesized in different ratios using the partially modified emulsification-diffusion method and fully characterized, and desirable nanoparticle was selected (PLGADEX20). At the second step, a double cross-linked hyaluronic acid (XHA) was prepared by mixing various ratios of amino-hyaluronic acid and aldehyde-hyaluronic acid in the presence of genipin. Finally, by mixing of various ratios of PLGADEX20 and Dexamethasone sodium phosphate (DEX) with different ratios of XHA, hybrid systems were prepared. Based on the characterization of hybrid samples and the release studies, hydrogels containing nanoparticles showed a controlled drug release, while the best sample with 3% of optimized nanoparticle was chosen. According to physiochemical and biological properties, these hybrid systems can be good candidates for anti-adhesion barriers, wound dressings, and novel drug delivery systems.
In the present comparative study, gelatin microspheres (GMs) were prepared by emulsification-solvent-extraction method using well-known crosslinker: glutaraldehyde (GA) and biocompatible silane-coupling agent:... more
In the present comparative study, gelatin microspheres (GMs) were prepared by emulsification-solvent-extraction method using well-known crosslinker: glutaraldehyde (GA) and biocompatible silane-coupling agent: glycidoxypropyltrimethoxysilane (GPTMS). Crosslinking with GA was done by a definite and common procedure, while GPTMS crosslinking potency was investigated after 5, 10, 24, and 48 h synthesis periods and the fabrication method was adjusted in order for preparation of GMs with optimized morphological and compositional characteristics. The prepared GMs were then evaluated and compared as drug delivery systems for the antibiotic vancomycin (Vm). Morphological observations, FTIR, ninhydrin assay, swelling behavior evaluation and Hydrolytic degradation analysis proved successful modification of GMs and revealed that increasing synthesis time from 5 h to 24 h and 48 h, when using GPTMS as crosslinker, led to formation of morphologically-optimized GMs with highest crosslinking degree (∼50%) and the slowest hydrolytic degradation rate. Such GMs also exhibited most sustained release period of Vm. The antibacterial test results against gram-positive bacterium Staphylococcus aureus, were in accordance with the release profiles of Vm, as well. Together, GPTMS-crosslinked GMs with their preferable characteristics and known as biocompatible gelatin-siloxane hybrids, could act as proper drug delivery systems for the sustained release of the antibiotic vancomycin.
The aim of the present study was to investigate the effect of click chemistry reactants on morphology and physico-chemical properties of alpha tricalcium phosphate (α-TCP)-based powders. The powders were synthesized by solid-state... more
The aim of the present study was to investigate the effect of click chemistry reactants on morphology and physico-chemical properties of alpha tricalcium phosphate (α-TCP)-based powders. The powders were synthesized by solid-state reaction. The powders were modified with azide and cycloalkyne to form triazole as a consequence of reactions of these molecules. The presence of the band related to the triazole ring and the click molecules in powder structure was confirmed by Fourier transform infrared (FTIR) and Liquid chromatography- mass spectroscopy (LC-MS) analyses. Based on scanning electron microscopy (SEM) observations, the modified powder exhibited a different microstructure and morphology of apatite precipitates after one day and 7 days of soaking in distilled water and SBF solution, respectively, with respect to unmodified powder. According to the acellular in vitro test, X-ray diffraction (XRD) patterns represented triple characteristic peaks of hydroxyapatite (HA) in modified powder compared with control. Besides, the tendency of conversion of α-TCP to HA is more enhanced for modified powder as well. The SEM analysis depicted the plate-like and needle-like morphology of HA on the surface of modified and control powders, respectively. Since plate-like morphology of HA enhances bone generation and is found in trabecular bone, therefore, a future design can be considered for triazole-modified α-TCP-based fillers as good candidates for bone substitute application.
In the present study, the effect of adding different concentrations of silicon on physical, mechanical and biological properties of a synthesized aqueous precipitated eggshell-derived hydroxyapatite (e-HA) was evaluated. No secondary... more
In the present study, the effect of adding different concentrations of silicon on physical, mechanical and biological properties of a synthesized aqueous precipitated eggshell-derived hydroxyapatite (e-HA) was evaluated. No secondary phases were detected by X-ray diffraction for the specimens e-HA and e-HA containing silicon (Si-e-HAs) before and after heating at 1200°C. A reduction in the crystallite size and a-axis as well as an increase in c-axis was occurred when silicon replacement was happened in the structure of e-HA. The presence of Si-O vibrations and carbonate modes for Si-e-HAs was confirmed by Fourier transform infrared spectroscopy analysis. The range of porosity and density was varied from 25% and 2.4 g cm–3 to 7% and 2.8 g cm–3 for e-HA and Si-e-HAs. The values of Young’s modulus (E) and compressive strength were varied for e-HA and Si-e-HAs. The porous structure of the samples was reduced when they were heated as e-HA kept the porous microstructure containing some dense areas and Si-e-HAs possessed a rough surface including slight levels of microporosity. The acellular in vitro bioactivity represented different apatite morphologies for e-HA and Si-e-HAs. The G-292 osteoblastic cells were stretched well on the surface with polygon-shaped morphology for 0.8Si-e-HA after 7 days of culture. According to MTT assay and alkaline phosphatase test, the maximum cell activity was related to 0.8Si-e-HA. The minimum inhibitory concentration for 0.8Si-e-HA and e-HA was estimated to be about 3.2 and 4.4 mg/mL, respectively. In overall, the sample 0.8Si-e-HA exhibited a higher bacteriostatic effect than e-HA against gram-negative bacterial strain Escherichia coli.
S53P4 bioactive glass nanoparticles (BGn) were prepared by the melting-quenching method at 1400 °C followed by ball milling. The prepared glass nanoparticles were used for surface decoration of poly-l-lactic acid (PLLA) nanofibers... more
S53P4 bioactive glass nanoparticles (BGn) were prepared by the melting-quenching method at 1400 °C followed by ball milling. The prepared glass nanoparticles were used for surface decoration of poly-l-lactic acid (PLLA) nanofibers fabricated by electrospinning method. The microstructure, morphology and chemical functional groups of the nanomaterials were characterized by XRD, FESEM, and FTIR techniques. The results confirmed the successful synthesis of amorphous glass nanoparticles with the diameter ranged from ~ 100 to 800 nm and PLLA nanofibers with an average diameter of 500 nm. PLLA/BGn nanocomposites showed a uniform distribution of the BGn on the surface of PLLA nanofibers. The growth, viability, and proliferation of the cultured human bone marrow mesenchymal stem cells (hMSCs) on the prepared nanomaterials were examined using various biological assays, including MTT cytotoxicity, ALP activity, calcium biomineralization, Alizarin red staining, and gene expression. The biological results clearly showed that the growth, proliferation and osteogenic ability of hMSCs were significantly improved due to the surface modification of PLLA nanofibers with BGn. It was concluded that the 3D structure, optimum porosity and balanced dissolution rate of PLLA/BGn nanocomposites led to the promoted cellular activity.
Biocompatible, biodegradable, non-toxic and non-carcinogenic gelatin nanoparticles, containing Tramadol HCl as a model drug, were prepared by the eater-in-oil nanoemulsion procedure. Sorbitan monooleate (span 80) and tween 80,... more
Biocompatible, biodegradable, non-toxic and non-carcinogenic gelatin nanoparticles, containing Tramadol HCl as a model drug, were prepared by the eater-in-oil nanoemulsion procedure. Sorbitan monooleate (span 80) and tween 80, glutaraldehyde and ethyl acetate were used as the surfactant, cross-linker and continuous phase, respectively. The obtained gelatin nanoparticles were identified via techniques like Field Emission Scanning Electron Microscopy (FESEM) and particle size analysis.The effects of various parameters such as surfactant concentration,magnetic stirring rate and temperature on particle size were studied. Nanoparticles droplets by an average size of 150 nm were obtained. The outcomes illustrated that gelatin nanoparticles could be a beneficial, sustained release delivery carrier for water-soluble drugs.
Strontium fluoride (SrF2) nanoparticles were synthesized using strontium chloride-choline chloride-water deep eutectic system at 80 °C. XRD, FESEM, TEM, EDS and Raman spectroscopy were employed to characterize the synthesized... more
Strontium fluoride (SrF2) nanoparticles were synthesized using strontium chloride-choline chloride-water deep eutectic system at 80 °C. XRD, FESEM, TEM, EDS and Raman spectroscopy were employed to characterize the synthesized nanoparticles. The analytical results confirmed the synthesis of SrF2 nanoparticles crystallized in the cubic crystal system with a mean crystal diameter of 26 nm, average particle size of 40 nm, Sr/F atomic ratio of 1.85 and high elemental and structural purity. The biodegradation and bioactivity of as-synthesized SrF2 nanoparticles were examined in the artificial saliva (AS) and simulated body fluid (SBF). The nanoparticles showed maximum weight loss of 33% after immersion in the AS solution for 14 days. The results of SEM-EDS and Raman spectroscopy revealed the formation of a dense apatite layer on the surface of the nanoparticles after 14 days of incubation in the SBF suggesting the good in vitro bioactivity. Antibacterial study demonstrated the excellent antibacterial activity of SrF2 nanoparticles against the Streptococcus mutans in such a way that ~ 100% bacteria elimination was achieved in presence of the nanoparticles compared with control. This was attributed to the increase of pH and osmotic pressure of the environment caused by the enhanced release of Sr2+ and F– ions from the synthesized SrF2 nanoparticles. MTT cytotoxicity assay and acridine orange (AO) staining test on the human mesenchymal stem cells (hMSCs) confirmed the biocompatibility of SrF2 nanoparticles.
Iron and cobalt materials have attracted enormous interest as low-cost alternatives to noble-metal catalysts able to catalyse oxygen reduction reaction. Here, the effect of the heteropolyacid H3PMo12O40 (HPMo) into the structure of new... more
Iron and cobalt materials have attracted enormous interest as low-cost alternatives to noble-metal catalysts able to catalyse oxygen reduction reaction. Here, the effect of the heteropolyacid H3PMo12O40 (HPMo) into the structure of new composites formed by Fe, Co and reduced-graphene oxide/chitosan (rGOCS) has been investigated. Chitosan was used as a nitrogen precursor for nanocarbon, while reduced graphene oxide was introduced to tune the electrical conductivity. The physicochemical properties of electrocatalysts were performed by Raman, XRD, XPS and TEM. Activity toward ORR was carried out in a three-electrode electrochemical cell using a rotating disk electrode (RDE). The molybdophosphoric acid incorporation into the structure of Fe/rGOCS composites resulted in an increase of the activity of the oxygen reduction reaction in alkaline medium. Furthermore, the replacement of iron by cobalt yielded in a great improvement of the activity and stability, which may open new avenues for the design of nanomaterials utilizing HPMo/reduced-graphene oxide/chitosan composites.
Objective(s): Three-dimensional structures such as nanofibrous scaffolds are being used in biomedical engineering as well as provide a site for cells to attach and proliferate leading to tissue formation. In the present study, poly(vinyl... more
Objective(s): Three-dimensional structures such as nanofibrous scaffolds are being used in biomedical engineering as well as provide a site for cells to attach and proliferate leading to tissue formation. In the present study, poly(vinyl pyrrolidone) (PVP)/ poly(vinyl alcohol)(PVA) hybrid nanofibrous scaffold was synthesized by electrospinning.
Materials and Methods: The effect of adding nano hydroxyapatite (n-HA) and also Epoxypropoxy-propyl-trimethoxysilane (EPPTMS) as a crosslinking agent on morphology and cell behaviour of the nanofibers was investigated.
Results: Scanning electron microscope (SEM) observations showed that all kinds of nanofibers represented uniform and well-ordered morphologies without formation of any beads by controlling the synthesis parameters. The average ûber diameter of PVP-PVA was 260 nm. n-HA was synthesized by wet chemical process. The synthesized n-HA was characterized by XRD for structural analysis. Transmission electron microscope (TEM) revealed that HA particles had nanosized dimensions (in the range of 40-100 nm). The presence of n-HA within electrospun PVP-PVA nanofibers was confirmed by XRD and Fourier transmission infrared spectroscopy (FTIR) analyses. The average ûber diameter was decreased to 136 nm when n-HA was added in the composition of PVP-PVA. FTIR analysis depicted that PVP-PVA nanofibers were linked to EPPTMS as a biocompatible material by the covalent bond. Although adding n-HA caused to decrease the diameter of PVP-PVA nanofibers, addition of EPPTMS within PVP/PVA/n-HA nanofibers induced increasing distribution of fiber diameter as it enhanced to 195nm. In addition, the proper proliferation of G292 osteoblastic cells without any cytotoxicity was observed for the nanofiber.
Conclusion: Since these materials have been known as biomaterials, PVP/PVA/n-HA-EPPTMS nanofibers can be propounded as a good candidate for bone tissue engineering application.
Materials and Methods: The effect of adding nano hydroxyapatite (n-HA) and also Epoxypropoxy-propyl-trimethoxysilane (EPPTMS) as a crosslinking agent on morphology and cell behaviour of the nanofibers was investigated.
Results: Scanning electron microscope (SEM) observations showed that all kinds of nanofibers represented uniform and well-ordered morphologies without formation of any beads by controlling the synthesis parameters. The average ûber diameter of PVP-PVA was 260 nm. n-HA was synthesized by wet chemical process. The synthesized n-HA was characterized by XRD for structural analysis. Transmission electron microscope (TEM) revealed that HA particles had nanosized dimensions (in the range of 40-100 nm). The presence of n-HA within electrospun PVP-PVA nanofibers was confirmed by XRD and Fourier transmission infrared spectroscopy (FTIR) analyses. The average ûber diameter was decreased to 136 nm when n-HA was added in the composition of PVP-PVA. FTIR analysis depicted that PVP-PVA nanofibers were linked to EPPTMS as a biocompatible material by the covalent bond. Although adding n-HA caused to decrease the diameter of PVP-PVA nanofibers, addition of EPPTMS within PVP/PVA/n-HA nanofibers induced increasing distribution of fiber diameter as it enhanced to 195nm. In addition, the proper proliferation of G292 osteoblastic cells without any cytotoxicity was observed for the nanofiber.
Conclusion: Since these materials have been known as biomaterials, PVP/PVA/n-HA-EPPTMS nanofibers can be propounded as a good candidate for bone tissue engineering application.
Iron and cobalt materials have attracted enormous interest as low-cost alternatives to noble-metal catalysts able to catalyse oxygen reduction reaction. Here, the effect of the heteropolyacid H3PMo12O40 (HPMo) into the structure of new... more
Iron and cobalt materials have attracted enormous interest as low-cost alternatives to noble-metal catalysts able to catalyse oxygen reduction reaction. Here, the effect of the heteropolyacid H3PMo12O40 (HPMo) into the structure of new composites formed by Fe, Co and reduced-graphene oxide/chitosan (rGOCS) has been investigated. Chitosan was used as a nitrogen precursor for nanocarbon, while reduced graphene oxide was introduced to tune the electrical conductivity. The physicochemical properties of electrocatalysts were performed by Raman, XRD, XPS and TEM. Activity toward ORR was carried out in a three-electrode electrochemical cell using a rotating disk electrode (RDE). The molybdophosphoric acid incorporation into the structure of Fe/rGOCS composites resulted in an increase of the activity of the oxygen reduction reaction in alkaline medium. Furthermore, the replacement of iron by cobalt yielded in a great improvement of the activity and stability, which may open new avenues for the design of nanomaterials utilizing HPMo/reduced-graphene oxide/chitosan composites.
Electrospinning method was employed for fabrication of SiO2-CaO-P2O5 bioactive glass (BG) nanofibers, poly-l-lactic acid (PLLA) nanofibers and nanocomposite scaffolds fabricated from as-prepared nanofibers. Characterization of the... more
Electrospinning method was employed for fabrication of SiO2-CaO-P2O5 bioactive glass (BG) nanofibers, poly-l-lactic acid (PLLA) nanofibers and nanocomposite scaffolds fabricated from as-prepared nanofibers. Characterization of the prepared nanofibers and scaffolds by XRD, FTIR, and SEM techniques revealed the formation of nanofibers with mean diameter of about 500 nm and fully fibrous scaffolds with porous structure and interconnected pores. The growth, viability and proliferation of cultured human bone marrow mesenchymal stem cells in the fabricated nanofibers and bioactive glass-poly-l-lactic acid (BG-PLLA) nanocomposite scaffolds were studied using various biological assays including MTT, ALP activity, calcium deposit content, Alizarin red staining, and RT-PCR test. Based on the obtained results, incorporation of BG nanofibers in the nanocomposite scaffolds causes the better biological behavior of the scaffolds. In addition, three-dimensional and fibrous-porous structure of the scaffolds further contributes to their improved cell behavior compared to the components.
In the present study, hydroxyapatite nanofibers were synthesized by electrospinning. The main focus is based on the effect of adding various ratios of calcium phosphate (Ca-P) sol to polymeric solutions of PVA and PVP with a fixed... more
In the present study, hydroxyapatite nanofibers were synthesized by electrospinning. The main focus is based on the effect of adding various ratios of calcium phosphate (Ca-P) sol to polymeric solutions of PVA and PVP with a fixed concentration of 10 and 15% (w/v), respectively, on the morphology and the diameter of the electrospun nanofibers. The electrical conductivity of pure PVA solution was higher than PVP (0.610 versus 0.06 mS/cm). However, by adding Ca-P sol, the solution conductivity increased to 23.5 and 34.4 mS/cm for PVA solution containing 15 (vol%) [A15] and PVP solution containing 25 (vol%) [V25] of the prepared sol, respectively. SEM observations showed that the fiber diameter of sample V25 (average diameter of 150 nm) was thinner and more uniform than A15 (average diameter of 170 nm). FE-SEM of sample V25 confirmed the results of SEM analysis as well. After heat treatment at 600 °C, powder-like particles were formed for the samples obtained from PVA solution without any fibers whereas a spaghetti-like morphology was seen for the samples V15 and V25. X-ray diffractograms of sample V25 indicated the presence of HA phase at two temperatures of 600 and 800 °C. However, in the latter case, minor phases of beta-tricalcium phosphate and calcium oxide were also identified. In addition, the crystal size increased from 2 nm at 600 °C to 16 nm at 800 °C. SEM/EDS analyses confirmed the formation of needle-like HA on surface of V25 after 7 days of soaking in simulated body fluid (SBF). Evaluation of cell growth demonstrated that human osteoblast-like cells were attached, spread, and grown well on the surface of V25. This event could be a good sign of biocompatibility of the fibers.
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In this paper, nanostructured carbonated hydroxyapatite powder was synthesized using biomimetic method. Physical properties and morphological features of the powder was studied using appropriate techniques such as BET, TEM, XRD and FTIR.... more
In this paper, nanostructured carbonated hydroxyapatite powder was synthesized using biomimetic method. Physical properties and morphological features of the powder was studied using appropriate techniques such as BET, TEM, XRD and FTIR. The powder was separately mixed with 3 wt. % solutions of either sodium alginate or chitosan to form different pastes. Rheological behavior of the pastes in oscillation mode was measured. Results showed that mean particle diameter and surface area of the powder were 3.9 μm and 154.8 m2/g, respectively. According to dynamic rheological evaluations, all pastes exhibited shear thinning behavior with linear viscoelastic limitations, although paste containing sodium alginate displayed broader linear viscoelastic range than others. Increasing concentration of sodium alginate or chitosan led to increment of viscosity, meanwhile sodium alginate produced a material of higher viscosity than did chitosan. When sodium alginate was employed, lower force was required for injection. Totally, these bioactive pastes potentially can be used for the treatment of hard tissues.
Gelatin microspheres (GMs) using various concentrations of epoxypropoxy-propyl-trimethoxysilane (EPPTMS) as a crosslinking agent were prepared. Since the crosslinking agent content and manufacturing conditions are crucial factors in the... more
Gelatin microspheres (GMs) using various concentrations of epoxypropoxy-propyl-trimethoxysilane (EPPTMS) as a crosslinking agent were prepared. Since the crosslinking agent content and manufacturing conditions are crucial factors in the characteristics of the microspheres, this study was carried out to evaluate the effect of processing variables on morphology, and in vitro behavior of GMs using acellular simulated body fluid (SBF). It was found that the best morphology was acquired in terms of both shape and uniformity for the GMs containing a certain concentration of EPPTMS (20wt%), whereas other concentrations yielded rambling spheres. The results revealed that the size of microspheres became smaller when both the oil-to-water ratio and agitation rate were increased. Moreover, the density of the crosslinking agent was also dependent on the above-mentioned factors in 20wt% EPPTMS. Different morphologies of hydroxyapatite deposits on the surface of GMs were observed after 14 days of soaking in SBF. These in vitro acellular studies were confirmed by SEM, FTIR, and XRD analyses. According to the results of UV–Vis spectroscopy, the GMs were released into the SBF solution in a time-dependent manner; however, the fastest rate of release occurred for the largest GM.
Research Interests:
Research Interests:
Titanium alloys have been extensively used as promising implant materials. The anodic oxide layer on the surface of this alloy can be a compact, porous or a tubular structure, which has a direct impact on the final... more
Titanium alloys have been extensively used as promising implant materials. The anodic oxide layer on the surface of this alloy
can be a compact, porous or a tubular structure, which has a direct impact on the final characteristics of the implants. In this
study, nano topographic oxide arrays were synthesized on the surface of titanium substrates using an anodic oxidation
technique. The anodization process was performed at a two-electrode electrochemical cell, and then the samples were annealed
to obtain crystalline structures. The synthesized samples were analyzed to evaluate the compositional phase, morphology,
surface hydrophilicity and corrosion resistance of the nanostructured oxide arrays in artificial saliva. Microscopic observations
confirmed the formation of a nanotubular structure on the surface of titanium substrate depending on the anodization condition.
After heat-treatment at 570 °C, crystallographic analyses showed that the obtained crystalline phase was a mixture of Anatase
and Rutile phases. The electrochemical impedance spectroscopy (EIS) results indicated a significant improvement in the
corrosion resistance and electrochemical stability of the anodized sample in artificial saliva compare to the control samples. In
addition, the anodized samples showed a better hydrophilic characteristics, viability and proliferation of periodontal ligament
cells in comparison with the un-anodized samples. This study demonstrated that the anodized titanium samples, with the
nanotubular structure on the surfaces, could be considered as a good candidate for dental implants.
can be a compact, porous or a tubular structure, which has a direct impact on the final characteristics of the implants. In this
study, nano topographic oxide arrays were synthesized on the surface of titanium substrates using an anodic oxidation
technique. The anodization process was performed at a two-electrode electrochemical cell, and then the samples were annealed
to obtain crystalline structures. The synthesized samples were analyzed to evaluate the compositional phase, morphology,
surface hydrophilicity and corrosion resistance of the nanostructured oxide arrays in artificial saliva. Microscopic observations
confirmed the formation of a nanotubular structure on the surface of titanium substrate depending on the anodization condition.
After heat-treatment at 570 °C, crystallographic analyses showed that the obtained crystalline phase was a mixture of Anatase
and Rutile phases. The electrochemical impedance spectroscopy (EIS) results indicated a significant improvement in the
corrosion resistance and electrochemical stability of the anodized sample in artificial saliva compare to the control samples. In
addition, the anodized samples showed a better hydrophilic characteristics, viability and proliferation of periodontal ligament
cells in comparison with the un-anodized samples. This study demonstrated that the anodized titanium samples, with the
nanotubular structure on the surfaces, could be considered as a good candidate for dental implants.
This study aims to detect the optimum antibacterial activity of silver-doped bioactive glasses (Ag-BGs) for prevention of post-transplant infections in tissue engineering. The results have shown that the Ag-BG samples had broad-spectrum... more
This study aims to detect the optimum antibacterial activity of silver-doped bioactive glasses (Ag-BGs) for prevention of post-transplant infections in tissue engineering. The results have shown that the Ag-BG samples had broad-spectrum antibacterial efficacy in an Ag concentration-dependent manner. The 2% Ag-BG had the highest effect during the first 10 min to 72 h. The minimum inhibitory concentration of 2% Ag-BG was estimated to be 2 mg/ml for Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) and 2.66 mg/ml for Staphylococcus aureus (S. aureus). A concentration of 0.5% Ag-BG repressed growth of E. coli after 1 h, but did not have any detectable antibacterial effect for longer periods. Evaluation of the effects of prepared Ag-BG on human osteoblast cells viability showed that 1 and 2% samples changed the cell proliferation rate in masses of more than 3.33 and 2 mg/ml, respectively. Moreover, in a typical manner, the release of Ag ions from the glass structure started immediately, continued steadily and affected bacterial growth when it reached its critical concentration in the medium. This systematic study can illustrate the optimum antibacterial property of the Ag-BG samples in masses of 3.33 and 2 mg/ml for 1 and 2% Ag, respectively, for prevention of post-transplant infections.
In the present study, gelatin-based hybrid fibrous scaffolds with and without silane agent (Epoxypropoxy-propyl-trimethoxysilane) were synthesized by electrospinning method. The effect of different concentrations of silane agent on... more
In the present study, gelatin-based hybrid fibrous scaffolds with and without silane agent (Epoxypropoxy-propyl-trimethoxysilane) were synthesized by electrospinning method. The effect of different concentrations of silane agent on morphology of the scaffolds was investigated. Scanning electron microscope observations showed that using the agent into the gelatin solution induced formation of fibers with appropriate uniformity with respect to the other samples. Nitrogen adsorption test revealed that there was no pore inside the fibers and surface area data were related to spaces between fibers. Physical analyses depicted that these kinds of fibers were linked to the silane agent by the covalent bond. Different morphologies of apatite were occurred on surface of the fibers after various days of soaking in simulated body fluid. Fourier transmission infrared spectroscopy and X-ray confirmed apatite formation on the fiber surface as well. Pore size distribution and specific surface area of these fibers after soaking nearly changed compared to the samples before soaking. Evaluation of cell viability and cell growth demonstrated that human osteoblast-like cells were attached, spread and grown well on the surface. This event could be a good sign of biocompatibility of the fibers.
In the present research, merwinite (M) scaffolds with and without nano-titanium dioxide (titania) were synthesized by water-based freeze casting method. Two different amounts (7.5 and 10 wt%) of n-TiO2 were added to M scaffolds. They were... more
In the present research, merwinite (M) scaffolds with and without nano-titanium dioxide (titania) were synthesized by water-based freeze casting method. Two different amounts (7.5 and 10 wt%) of n-TiO2 were added to M scaffolds. They were sintered at temperature of 1573.15°K and at cooling rate of 4°K/min. The changes in physical and mechanical properties were investigated. The results showed that although M and M containing 7.5 wt% n-TiO2 (MT7.5) scaffolds had approximately the same microstructures in terms of pore size and wall thickness, these factors were different for sample MT10. In overall, the porosity, volume and linear shrinkage were decreased by adding different weight ratios of n-TiO2 into the M structure. According to the obtained mechanical results, the optimum mechanical performance was related to the sample MT7.5 (E = 51 MPa and σ = 2 MPa) with respect to the other samples, i.e.: M (E = 47 MPa and σ = 1.8 MPa) and MT10 (E = 32 MPa and σ = 1.4 MPa). The acellular in vitro bioactivity experiment confirmed apatite formation on the surfaces of all samples for various periods of soaking time. Based on cell study, the sample which possessed favorable mechanical behavior (MT7.5) supported attachment and proliferation of osteoblastic cells. These results revealed that the MT7.5 scaffold with improved mechanical and biological properties could have a potential to be used in bone substitute.
In this study, poly(ε-caprolactone) (PCL), gelatin (GEL) and nanocrystalline hydroxyapatite (HAp) was applied to fabricate novel PCL-GEL-HAp nanaocomposite scaffolds through a new fabrication method. With the aim of finding the best... more
In this study, poly(ε-caprolactone) (PCL), gelatin (GEL) and nanocrystalline hydroxyapatite (HAp) was applied to fabricate novel PCL-GEL-HAp nanaocomposite scaffolds through a new fabrication method. With the aim of finding the best fabrication method, after testing different methods and solvents, the best method and solvents were found, and the nanocomposites were prepared through layer solvent casting combined with freeze-drying. Acetone and distillated water were used as the PCL and GEL solvents, respectively. The mechanical test showed that the increasing of the PCL weight through the scaffolds caused the improvement of the final nanocomposite mechanical behavior due to the increasing of the ultimate stress, stiffness and elastic modulus (8 MPa for 0% wt PCL to 23.5 MPa for 50% wt PCL). The biomineralization investigation of the scaffolds revealed the formation of bone-like apatite layers after immersion in simulated body fluid (SBF). In addition, the in vitro cytotoxity of the scaffolds using L929 mouse fibroblast cell line (ATCC) indicated no sign of toxicity. These results indicated that the fabricated scaffold possesses the prerequisites for bone tissue engineering applications.
The need for bone repair has increased as the population ages. In this research, calcium phosphate cements, with and without chitosan (CS) and hyaluronic acid (HA), were synthesized. The composition and morphological properties of cements... more
The need for bone repair has increased as the population ages. In this research, calcium phosphate cements, with and without chitosan (CS) and hyaluronic acid (HA), were synthesized. The composition and morphological properties of cements were evaluated by X-ray diffraction and scanning electron microscopy. The acellular in vitro bioactivity revealed that different apatite morphologies were formed on the surfaces of cements after soaking in simulated body fluid. The in vitro osteoblastic cell biocompatibility of in situ forming cements was evaluated and compared with those of conventional calcium phosphate cements (CPCs). The viability and growth rate of the cells were similar for all CPCs, but better alkaline phosphatase activity was observed for CPC with CS and HA. Calcium phosphate cements supported attachment of osteoblastic cells on their surfaces. Spindle-shaped osteoblasts with developed cytoplasmic membrane were found on the surfaces of cement samples after 7 days of culture. These results reveal the potential of the CPC–CS/HA composites to be used in bone tissue engineering.
In the present research, strontium containing nano-bioactive glass (NBG-Sr) was synthesized by sol-gel method. The morphology was analyzed by transmission electron microscope (TEM). Different amounts (0.5 to 5 wt%) of... more
In the present research, strontium containing nano-bioactive glass (NBG-Sr) was
synthesized by sol-gel method. The morphology was analyzed by transmission electron microscope
(TEM). Different amounts (0.5 to 5 wt%) of NBG-Sr were then added to biphasic calcium
phosphate (BCP). They were sintered at different temperatures, i.e., 1100, 1200 and 1300 °C and
changes in physical and mechanical properties were investigated. A sharp decrease in pore volume
was observed as the temperature increased. The maximum bending strength (~45 MPa) was
achieved for BCP which was mixed with 3 wt% NBG-Sr and sintered at 1200 °C. This value was
approximately the same when it was sintered at 1300 °C. The bending strength failed when both
lower and higher amounts of 3 wt% NBG-Sr were utilized. Therefore, sintering of composites at
1200 °C was economically reasonable. The X-ray results showed that NBG-Sr additive did not
change the phase composition of BCP when it was heat treated at 1200 °C. The attachment and
proliferation of rat calvarium-derived osteoblasts on samples sintered at 1200 °C were also
evaluated by scanning electron microscopy (SEM). Based on cell studies, all NBG-Sr-added BCPs
supported attachment and proliferation of osteoblastic cells. Overall, biphasic calcium phosphate
materials with improved mechanical and biological properties can be produced by using certain
quantity of strontium-containing bioactive glass particles.
synthesized by sol-gel method. The morphology was analyzed by transmission electron microscope
(TEM). Different amounts (0.5 to 5 wt%) of NBG-Sr were then added to biphasic calcium
phosphate (BCP). They were sintered at different temperatures, i.e., 1100, 1200 and 1300 °C and
changes in physical and mechanical properties were investigated. A sharp decrease in pore volume
was observed as the temperature increased. The maximum bending strength (~45 MPa) was
achieved for BCP which was mixed with 3 wt% NBG-Sr and sintered at 1200 °C. This value was
approximately the same when it was sintered at 1300 °C. The bending strength failed when both
lower and higher amounts of 3 wt% NBG-Sr were utilized. Therefore, sintering of composites at
1200 °C was economically reasonable. The X-ray results showed that NBG-Sr additive did not
change the phase composition of BCP when it was heat treated at 1200 °C. The attachment and
proliferation of rat calvarium-derived osteoblasts on samples sintered at 1200 °C were also
evaluated by scanning electron microscopy (SEM). Based on cell studies, all NBG-Sr-added BCPs
supported attachment and proliferation of osteoblastic cells. Overall, biphasic calcium phosphate
materials with improved mechanical and biological properties can be produced by using certain
quantity of strontium-containing bioactive glass particles.
In this research, sol–gel-derived nanostructured calcium magnesium silicate (merwinite)-based scaffolds were fabricated by water-based freeze casting method. The effect of cooling rate and sintering temperature on pore sizes and... more
In this research, sol–gel-derived nanostructured calcium magnesium silicate (merwinite)-based scaffolds were fabricated by water-based freeze casting method. The effect of cooling rate and sintering temperature on pore sizes and mechanical characteristics of the scaffolds was studied. Microstructure and surface morphology of scaffolds were also observed by scanning electron microscopy before and after various time intervals of soaking in simulated body fluid. The results showed that increasing temperature at the constant rate led to increasing the parameters of volume and linear shrinkage, strength (σ), and Young’s modulus (E) but decreasing porosity. This increase was significant for strength and Young’s modulus. In addition, with the increase of rate at the constant temperature, the parameters of volume and linear shrinkage and also porosity decreased whereas strength and Young’s modulus increased significantly. According to the obtained mechanical results, the best mechanical properties were achieved when the scaffold was prepared at cooling rate and sintering temperature of 277.15°K/min and 1623.15°K, respectively (E = 0.048 GPa and σ = 2 MPa). These values were closer to the lower limit of the values for cancellous bone. The acellular in vitro bioactivity revealed that different apatite morphologies were formed on the surfaces for various periods of soaking time when the scaffolds prepared at the freezing temperature of 277.15°K/min and at the two different sintering temperatures. The favorable mechanical behavior of the porous constructs, coupled with the ability of forming apatite particles on the surface of scaffold, indicates the potential of the present freeze casting route for the production of porous scaffolds for bone tissue engineering.
Calcium phosphate cements (CPCs) have been used in a number of medical and dental procedures due to their excellent osteoconductivity and bone replacement capability. However, the low mechanical properties of CPCs prohibit their usage in... more
Calcium phosphate cements (CPCs) have been used in a number of medical and dental procedures due to their excellent osteoconductivity and bone replacement capability. However, the low mechanical properties of CPCs prohibit their usage in many unsupported defects and stress bearing locations. Bioactive glass fiber (BGF) reinforced-CPC with enhanced mechanical property has been recently developed [Nezafati et al. 2011, Ceramics International]. In the present study, the in vitro bioactivity and cellular properties of the CPC optimally reinforced with 15 vol% BGFs were evaluated and compared with a control group, i.e. unreinforced CPC. The samples were soaked in simulated body fluid (SBF) for different time intervals and were then characterized by various techniques. Carbonate substituted apatite crystals with oriented plate-like morphology were also found on the surface of the samples. Furthermore, rat-derived osteoblastic cells were seeded on the samples for different times and evaluated in terms of proliferation, morphology and alkaline phosphatase (ALP) activity. In addition, the proliferation of osteoblastic cells on samples and increasing in level of alkaline phosphatase enzyme were observed as a function of time. The obtained results indicated that the reinforced composite made of CPC and BGFs could be considered as a highly bioactive material for bone tissue defect treatment after successful passage of in vivo experiments.
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... more
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 maintaining 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 composite were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infra-red spectroscopy (FTIR) techniques, respectively.
Dycal® is a paste-paste calcium hydroxide dental cement uses as pulp capping and liner in dentistry. First paste (base paste) contains titanium dioxide and barium sulphate in glycol disalicylate and second paste (catalyst paste) contains... more
Dycal® is a paste-paste calcium hydroxide dental cement uses as pulp capping and liner in dentistry. First paste (base paste) contains titanium dioxide and barium sulphate in glycol disalicylate and second paste (catalyst paste) contains calcium hydroxide, zinc oxide and zinc stearate in ethyl toluene sulphonamide. Equal amounts of base and catalyst paste were mixed together and a hard mass is obtained after a certain time. The set material consists of TiO2, ZnO (fillers), BaSO4 (radiopacifier) and free unreacted Ca(OH)2 dispersed in an amorphous calcium phenolate matrix. This unreacted calcium hydroxide is responsible for biological properties of Dycal® (antibacterial and formation of reparative dentin).
In this research Dycal® has been fabricated and furthermore glycol disalicylate was gradually replaced by methyl salicylate up to 20 % in base paste. Cements were characterized by X-ray diffraction (XRD) and Fourier
transform infra-red (FTIR) and scanning electron microscopy (SEM). Also effect of the replacement was investigated on setting time, water solubility, pH and compressive strength of the cement. Results showed that unreacted calcium hydroxide decreased in set cement when methyl salicylate increase in base paste and therefore, and pH of distilled water containing cement decrease by this replacement. Setting time and water solubility also decreased when methyl salicylate increased in base paste (from 5.5 to 3 min and 4.5% to 2.5% respectively). The compressive strength showed no changes by this replacement.
In this research Dycal® has been fabricated and furthermore glycol disalicylate was gradually replaced by methyl salicylate up to 20 % in base paste. Cements were characterized by X-ray diffraction (XRD) and Fourier
transform infra-red (FTIR) and scanning electron microscopy (SEM). Also effect of the replacement was investigated on setting time, water solubility, pH and compressive strength of the cement. Results showed that unreacted calcium hydroxide decreased in set cement when methyl salicylate increase in base paste and therefore, and pH of distilled water containing cement decrease by this replacement. Setting time and water solubility also decreased when methyl salicylate increased in base paste (from 5.5 to 3 min and 4.5% to 2.5% respectively). The compressive strength showed no changes by this replacement.
In the present study, a bioceramic-based composite was prepared by sintering compacts made up of mixtures of hydroxyapatite (HA) and sol–gel-derived bioactive glass (64SiO2-26CaO-5MgO-5ZnO) (based on mol%) powders. HA powder was mixed... more
In the present study, a bioceramic-based composite was prepared by sintering compacts made up of mixtures of hydroxyapatite (HA) and sol–gel-derived bioactive glass (64SiO2-26CaO-5MgO-5ZnO) (based on mol%) powders. HA powder was mixed with different concentrations of the glass powders up to 30 wt.%. The effect of adding bioactive glass powder to HA matrix, on the mechanical properties of the composite was assessed by compression test. The specimen with the highest compressive strength was chosen to be immersed in simulated body fluid (SBF) to study apatite forming ability and dissolution behavior. It was found that compressive strength of the specimen was decreased 65% after maintaining in the SBF for 14 days. X-ray diffraction (XRD) showed prevalence of HA and β-TCP related peaks. Also, the surface morphology of the composite was observed using scanning electron microscopy (SEM). The study of degradation behavior revealed Si release capability of this composite. Biological evaluations in vitro confirmed the composite studied could induce osteoblast-like cells' activities.
Research Interests:
Calcium phosphate cements (CPCs) have been used in a number of medical and dental procedures due to their excellent osteoconductivity and bone replacement capability. However, the low mechanical properties of CPCs prohibit their usage in... more
Calcium phosphate cements (CPCs) have been used in a number of medical and dental procedures due to their excellent osteoconductivity and bone replacement capability. However, the low mechanical properties of CPCs prohibit their usage in many unsupported defects and stress bearing locations. Bioactive glass fiber (BGF) reinforced-CPC with enhanced mechanical property has been recently developed [Nezafati et al. 2011, Ceramics International]. In the present study, the in vitro bioactivity and cellular properties of the CPC optimally reinforced with 15 vol% BGFs were evaluated and compared with a control group, i.e. unreinforced CPC. The samples were soaked in simulated body fluid (SBF) for different time intervals and were then characterized by various techniques. Carbonate substituted apatite crystals with oriented plate-like morphology were also found on the surface of the samples. Furthermore, rat-derived osteoblastic cells were seeded on the samples for different times and evaluated in terms of proliferation, morphology and alkaline phosphatase (ALP) activity. In addition, the proliferation of osteoblastic cells on samples and increasing in level of alkaline phosphatase enzyme were observed as a function of time. The obtained results indicated that the reinforced composite made of CPC and BGFs could be considered as a highly bioactive material for bone tissue defect treatment after successful passage of in vivo experiments.
Research Interests:
Ag ions are known for their antibacterial effects. Ag containing silicate glasses have been extended to create bioactive glasses exhibiting inhibitory effects on bacterial growth using different techniques. In this work, calcium and... more
Ag ions are known for their antibacterial effects. Ag containing silicate glasses have been extended to create bioactive glasses exhibiting inhibitory effects on bacterial growth using different techniques. In this work, calcium and calcium/silver silicophosphate glasses were synthesized from the sol–gel process and their physico-chemical and in vitro biological properties were studied and compared to each other. The effect of silver concentration on in vitro bioactivity and antibacterial properties of the glasses was investigated. Ag2O was substituted for CaO in the glass formula up to 2 mol% and in vitro bioactivity of the samples was evaluated by soaking them in simulated body fluid followed by structural characterization using XRD, FTIR and SEM techniques. The results showed that both glasses favored precipitation of calcium phosphate layer when they were soaked in simulated body fluid; however the morphology of apatite crystals changed for 2%mol silver containing sample. 2% mol Ag2O substituted for CaO seemed to stimulate the rate of precipitation slightly. The in vitro biodegradation rate of the silver/calcium silicophosphate glasses was lower than that of silver-free one (control). Also, the antibacterial properties of the samples indicated that these effects improved by increasing silver concentration in bioactive glass composition.
Basic drawbacks of calcium phosphate cements (CPCs) are the brittleness and low strength behavior which prohibit their use in many stress-bearing locations, unsupported defects, or reconstruction of thin bones. Recently, to solve these... more
Basic drawbacks of calcium phosphate cements (CPCs) are the brittleness and low strength behavior which prohibit their use in many stress-bearing locations, unsupported defects, or reconstruction of thin bones. Recently, to solve these problems, researchers investigated the incorporation of fibers into CPCs to improve their strength. In the present study, various amounts of a highly bioactive glass fiber were incorporated into calcium phosphate bone cement. The obtained results showed that the compressive strength of the set cements without any fibers optimally increased by further addition of the fiber phase. Also, both the work-of-fracture and elastic modulus of the cement were considerably increased after applying the fibers in the cement composition. Herein, with the aim of using the reinforced-CPC as appropriate bone filler, the prepared sample was evaluated in vitro using simulated body fluid (SBF) and osteoblast cells. The samples showed significant enhancement in bioactivity within few days of immersion in SBF solution. Also, in vitro experiments with osteoblast cells indicated an appropriate penetration of the cells, and also the continuous increase in cell aggregation on the samples during the incubation time demonstrated the ability of the reinforced-CPC to support cell growth. Therefore, we concluded that this filler and strong reinforced-CPC may be beneficial to be used as bone fillers in surgical sites that are not freely accessible by open surgery or when using minimally invasive techniques.
Key Engineering Materials Vols. 493-494 (2012) pp 209-214.
Key Engineering Materials Vols. 493-494 (2012) pp 209-214.
Research Interests:
Human beings are often infected by microorganisms in the living environment. Among various natural and inorganic substances, silver or silver ions have a powerful antibacterial activity. In the present study, the bioactivity and... more
Human beings are often infected by microorganisms in the living environment. Among various natural and inorganic substances, silver or silver ions have a powerful antibacterial activity. In the present study, the bioactivity and antibacterial activity of the SiO2–CaO–P2O5–Ag2O was compared with that of its ternary counterpart glass system (as a control sample) in vitro. The molar ratio of silver oxide in the bioactive glass composition was considered as different amount (0.5%, 1% and 2%). The surface characterization was evaluated after soaking in simulated body fluid (SBF). The sharpest apatite peak in X-ray diffraction (XRD) analyse after 7 days soaking in SBF was observed for 2% Ag sample (2%Ag-BG). Hence, the antibacterial effects of 2%Ag-BG sample against 2 gram negatives bacterium were examined by agar plate test. The result showed that the amount of silver did not prevent the HAp formation. Also, the antibacterial properties of 2%Ag-BG sample indicated near 100% bactericidal ratio (according to the width of antibacterial halo).
bisphosphonates are a class of drugs that inhibit osteoclast action and the resoption of bone. Osteoporosis is caused to abnormal function of osteoclasts. When calcium phosphate cements in osteoprotics patients are used, loosening will... more
bisphosphonates are a class of drugs that inhibit osteoclast action and the resoption of bone.
Osteoporosis is caused to abnormal function of osteoclasts. When calcium phosphate cements in
osteoprotics patients are used, loosening will be happened because of increased activity of
osteoclast in implant situation. If we use bisphosphonates in calcium phosphate cement
composition this problem will overcome. In addition as we have investigated the properties of
biphosphonate added cement, we observed better properties that only made by some additives, so
bisphosphonate could be a very interesting additive too, for achieving to optimum properties.
Osteoporosis is caused to abnormal function of osteoclasts. When calcium phosphate cements in
osteoprotics patients are used, loosening will be happened because of increased activity of
osteoclast in implant situation. If we use bisphosphonates in calcium phosphate cement
composition this problem will overcome. In addition as we have investigated the properties of
biphosphonate added cement, we observed better properties that only made by some additives, so
bisphosphonate could be a very interesting additive too, for achieving to optimum properties.
In this study, the compressive strength and bioactivity of strong polymeric calcium phosphate cement (PCPC), made by mixing a calcium phosphate powder (a mixture of tetracalcium phosphate and dicalcium phosphate dihydrate) and an aqueous... more
In this study, the compressive strength and bioactivity of strong polymeric calcium phosphate cement (PCPC), made by mixing a calcium phosphate powder (a mixture of tetracalcium phosphate and dicalcium phosphate dihydrate) and an aqueous solution of poly(acrylic/itaconic)
acid, were investigated. The characteristics of the cement such as phase composition, setting reaction products and microstructure were analysed and compared to those of a control sample made by the same solid phase and water as a liquid. The hard tissue healing capability of PCPC was tested in a rabbit model by radiographical observations of the healing process as well as the cement condition. The results showed that the compressive strength of the set PCPC was about 35 MPa before soaking in a simulated body fluid (SBF), which was much higher than that of the control specimen. However, it sharply decreased when the cement was immersed in the SBF. X-ray diffraction analysis revealed that tricalcium phosphate was formed in the set PCPC and only a small amount of hydroxyapatite was produced after seven days soaking. In contrast, hydroxyapatite was almost the only phase of the control specimen after the soaking period.
Radiography tests showed a cement (PCPC) with an irregular macrostructure after three months implantation, with a decreased radiopacity, and without any periosteal or intercortical callus formation.
acid, were investigated. The characteristics of the cement such as phase composition, setting reaction products and microstructure were analysed and compared to those of a control sample made by the same solid phase and water as a liquid. The hard tissue healing capability of PCPC was tested in a rabbit model by radiographical observations of the healing process as well as the cement condition. The results showed that the compressive strength of the set PCPC was about 35 MPa before soaking in a simulated body fluid (SBF), which was much higher than that of the control specimen. However, it sharply decreased when the cement was immersed in the SBF. X-ray diffraction analysis revealed that tricalcium phosphate was formed in the set PCPC and only a small amount of hydroxyapatite was produced after seven days soaking. In contrast, hydroxyapatite was almost the only phase of the control specimen after the soaking period.
Radiography tests showed a cement (PCPC) with an irregular macrostructure after three months implantation, with a decreased radiopacity, and without any periosteal or intercortical callus formation.
In this study, nanocomposite of 50 wt% calcium sulfate and 50 wt% nanocrystalline apatite was produced and its biocompatibility, physical and structural properties were compared with pure calcium sulfate (CS) cement. Indomethacin (IM), a... more
In this study, nanocomposite of 50 wt% calcium sulfate and 50 wt% nanocrystalline apatite was produced and its biocompatibility, physical and structural properties were compared with pure calcium sulfate (CS) cement. Indomethacin (IM), a non-steroidal anti-inflammatory drug, was also loaded on both CS and nanocomposite cements and its in vitro release was evaluated over a period of time. The effect of the loaded IM on basic properties of the cements was also investigated. Biocompatibility tests showed a partial cytotoxicity in CS cement due to the reduced number of viable mouse fibroblast L929 cells in contact with the samples as well as spherical morphologies of the cells. However, no cytotoxic effect was observed for nanocomposite cement and no significant difference was found between the number
of the cells seeded in contact with this specimens and culture plate as control. Other results showed that the setting time and injectability of the nanocomposite cement was much higher than those of CS cement, whereas reverse result obtained for compressive strength. In addition, incorporation of IM into compositions slightly increased the initial setting time and injectability of the cements and did not change
their compressive strength. While a fast IM release was observed from CS cement in which about 97% of
the loaded drug was released during 48 h, nanocomposite cement showed a sustained release behavior in
which 80% of the loaded IM was liberated after 144 h. Thus, the nanocomposite can be a more appropriate
carrier than CS for controlled release of IM in bone defect treatments.
of the cells seeded in contact with this specimens and culture plate as control. Other results showed that the setting time and injectability of the nanocomposite cement was much higher than those of CS cement, whereas reverse result obtained for compressive strength. In addition, incorporation of IM into compositions slightly increased the initial setting time and injectability of the cements and did not change
their compressive strength. While a fast IM release was observed from CS cement in which about 97% of
the loaded drug was released during 48 h, nanocomposite cement showed a sustained release behavior in
which 80% of the loaded IM was liberated after 144 h. Thus, the nanocomposite can be a more appropriate
carrier than CS for controlled release of IM in bone defect treatments.
In the present study, release properties of antibiotic-loaded cement-type nanocomposites of biomimetic apatite and calcium sulfate were studied. Nanocrystalline component of the nanocomposite was synthesized by soaking a mixture of... more
In the present study, release properties of antibiotic-loaded cement-type nanocomposites of biomimetic apatite and calcium sulfate were studied. Nanocrystalline component of the nanocomposite was synthesized by soaking a mixture of calcium phosphate reactants in tris-buffered simulated body fluid (SBF). The release patterns of cephalexin and
gentamicin from both pure calcium sulfate and nanocomposite cements into SBF were collected up to 144 h and fitted by Higuchi and Weibull equations. The effect of loaded
antibiotics on physical properties of the cements was also evaluated. Fast release behavior of both antibiotics was obtained from calcium sulfate matrix, in which 80–85% of the loaded antibiotics were liberated during the first 10 h of elution. In contrast, an administered elution was acquired from nanonocomposite materials so that the release was controlled, in all cases, by a combined mechanism; major mechanism was drug diffusion through the matrix and the
minor was matrix dissolution. The results showed that the initial setting time and injectability of cements were increased from 7 min and 71% for pure calcium sulfate cement (powder-to liquid ratio 5 2.5 g/mL) to 33 min and 95% for the nanocomposite cement containing 60 wt % apatite, respectively. The compressive strength of nanocomposite was about 0.9 MPa, nearly four times lower than that of pure calcium sulfate. In addition, the use of cephalexin
monohydrate did not influence the setting time and compressive strength of the cements, whereas (adding) gentamicin sulfate significantly improved these properties.
gentamicin from both pure calcium sulfate and nanocomposite cements into SBF were collected up to 144 h and fitted by Higuchi and Weibull equations. The effect of loaded
antibiotics on physical properties of the cements was also evaluated. Fast release behavior of both antibiotics was obtained from calcium sulfate matrix, in which 80–85% of the loaded antibiotics were liberated during the first 10 h of elution. In contrast, an administered elution was acquired from nanonocomposite materials so that the release was controlled, in all cases, by a combined mechanism; major mechanism was drug diffusion through the matrix and the
minor was matrix dissolution. The results showed that the initial setting time and injectability of cements were increased from 7 min and 71% for pure calcium sulfate cement (powder-to liquid ratio 5 2.5 g/mL) to 33 min and 95% for the nanocomposite cement containing 60 wt % apatite, respectively. The compressive strength of nanocomposite was about 0.9 MPa, nearly four times lower than that of pure calcium sulfate. In addition, the use of cephalexin
monohydrate did not influence the setting time and compressive strength of the cements, whereas (adding) gentamicin sulfate significantly improved these properties.
In this study, macroporous bioactive nanocomposite scaffolds were developed using cross-linked gelatin and bioactive glass (BaG) nanoparticles. First, BaG nanoparticles were synthesized via sol–gel method and characterized. Then,... more
In this study, macroporous bioactive nanocomposite scaffolds were developed using cross-linked gelatin and bioactive glass (BaG) nanoparticles. First, BaG nanoparticles were synthesized via sol–gel method and characterized. Then, macroporous nanocomposites were prepared through layer solvent casting combined with freeze-drying and lamination techniques. This research has developed a new composition to produce a new bioactive nanocomposite which is porous with three-dimensional (3D) inter-connected microstructure, pore sizes are 200–500 μm, porosity are 72–86% and BaG nanoparticles are dispersed evenly among cross-linked gelatin matrices. It is mentionable that in this study, we have reported the formation of chemical bonds between BaG nanoparticles and gelatin for the first time. Finally, the in vitro cytocompatibility of the nanocomposite scaffolds was tested using SaOS-2 cell line.
ricated from cross-linked gelatine (Gel) and nano bioactive glass (nBG) through layer solvent casting combined with freeze-drying and lamination techniques. This study has developed a new composition to produce a new bioactive... more
ricated from cross-linked gelatine (Gel) and nano bioactive glass (nBG) through layer solvent casting combined
with freeze-drying and lamination techniques. This study has developed a new composition to produce a new bioactive nanocomposite which is porous with interconnected microstructure, pore sizes are 200-500 μm, porosity are 72%-86%. Also, we have reported formation of chemical bonds between nBG and Gel for the first time. Finally, the in vitro cytocompatability of the scaffolds was assessed using MTT assay and cell attachment study. Results indicated no sign of toxicity and cells found to be attached to the pore walls offered by the scaffolds.
These results suggested that the developed nanocomposite scaffold possess the prerequisites for bone tissue engineering scaffolds and it can be used for tissue engineering applications.
with freeze-drying and lamination techniques. This study has developed a new composition to produce a new bioactive nanocomposite which is porous with interconnected microstructure, pore sizes are 200-500 μm, porosity are 72%-86%. Also, we have reported formation of chemical bonds between nBG and Gel for the first time. Finally, the in vitro cytocompatability of the scaffolds was assessed using MTT assay and cell attachment study. Results indicated no sign of toxicity and cells found to be attached to the pore walls offered by the scaffolds.
These results suggested that the developed nanocomposite scaffold possess the prerequisites for bone tissue engineering scaffolds and it can be used for tissue engineering applications.
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... more
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 maintaining 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 composite were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infra-red spectroscopy (FTIR) techniques, respectively.
In the present study, a bioceramic-based composite was prepared by sintering compacts made up of mixtures of hydroxyapatite (HA) and sol–gel-derived bioactive glass (64SiO2-26CaO-5MgO-5ZnO) (based on mol%) powders. HA powder was mixed... more
In the present study, a bioceramic-based composite was prepared by sintering compacts made up of mixtures of hydroxyapatite (HA) and sol–gel-derived bioactive glass (64SiO2-26CaO-5MgO-5ZnO) (based on mol%) powders. HA powder was mixed with different concentrations of the glass powders up to 30 wt.%. The effect of adding bioactive glass powder to HA matrix, on the mechanical properties of the composite was assessed by compression test. The specimen with the highest compressive strength was chosen to be immersed in simulated body fluid (SBF) to study apatite forming ability and dissolution behavior. It was found that compressive strength of the specimen was decreased 65% after maintaining in the SBF for 14 days. X-ray diffraction (XRD) showed prevalence of HA and β-TCP related peaks. Also, the surface morphology of the composite was observed using scanning electron microscopy (SEM). The study of degradation behavior revealed Si release capability of this composite. Biological evaluations in vitro confirmed the composite studied could induce osteoblast-like cells' activities.