Sharif Digital Repository

A series of herbal extract incorporated into poly(lactic acid) (PLA) composite nanofibrous scaffolds were successfully prepared by using electrospinning technique. Equisetum arvense extract (EE) and nanohydroxyapatite (nHA) in different quantities were loaded into PLA solution to fabricate composite nanofibrous webs under various electrospinning conditions. Uniform nanofibers were obtained with an average diameter of 157 ± 47 nm in the case of those containing the herbal extract. Characterization of the webs was carried out by means of Fourier transform infrared (FTIR) spectroscopy, field emission-scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), and... 

Natural silk fibroin (SF) polymer has biomedical and mechanical properties as a biomaterial for bone tissue engineering scaffolds. Freeze-dried porous nanocomposite scaffolds were prepared from silk fibroin and titanium dioxide (TiO2) nanoparticles as a bioactive reinforcing agent by a phase separation method. In order to fabricate SF/TiO2 scaffolds, 5, 10, 15 and 20 wt% of the TiO2 were added to the SF. The phase structure, functional groups and morphology of the scaffolds were evaluated using X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy techniques, respectively. Porosity of the scaffolds was measured by Archimedes' Principle. In addition,... 

A new ternary nanocomposite based on graphene oxide (GO), polypyrrole (PPy) and vanadium pentoxide (V2O5) is obtained via one-step electrochemical deposition process. Electrochemical deposition of V2O5, PPy and GO on a stainless steel (SS) substrate is conducted from an aqueous solution containing vanadyl acetate, pyrrole and GO to get V2O5/PPy/GO nanocomposite. Characterization of the electrode material is carried out by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM). The electrochemical performance of the as-prepared nanocomposite is evaluated by... 

For the efficient removal of some anionic dyes, a novel adsorbent was developed. The adsorbent was prepared by coating a synthetic polymer on magnetite nanosphere surface as a magnetic carrier. The synthesized nano-adsorbent was fully characterized using Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer, X-ray diffractometer, scanning electron microscope, and transmission electronic microscopy measurements. The synthesized nano-adsorbent showed high adsorption capacity towards removal of some anionic dyes (221.4, 201.6, and 135.3 mg g-1 for reactive red 195, reactive yellow 145, and reactive blue 19 dye, respectively) from aqueous samples. The dye adsorption was... 

Inorganic NiTiO3 nano-pigments have received recent attentions as possible candidates for cool materials to be used in building roofs and facades. In this paper, we have attempted to develop an innovative low temperature pathway (processed at 50 °C) for obtaining NiTiO3 nanocrystals by an ultrasound-assisted wet chemical processing method. Different characterization techniques such as X-ray diffraction (XRD), Fourier transform infrared spectrometry (FT-IR), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and diffuse reflectance spectroscopy (DRS) were used in order to characterize the size, morphology and optical responses of the obtained NiTiO3... 

ZnO/CuO nanofibers, with different CuO concentrations, were fabricated by one-step electrospinning of the polymer precursor and annealing in air. Scanning electron microscopy (SEM) showed smooth and beadless morphology for the synthesized nanofibers, while X-ray diffraction (XRD) analysis revealed formation of hexagonal and monoclinic crystalline structure phases for ZnO and CuO nanofibers, respectively. X-ray photoelectron spectroscopy (XPS) analysis confirmed the presence of CuO on the surface of ZnO nanofibers. For further confirming the formation of chemical bonds, Fourier transform infrared (FT-IR) spectroscopy was employed. The effect of Cu contents in the overall electronic band... 

In this study, superhydrophobic dual layer membranes with highly porous structure were fabricated using electrospinning and electrospraying techniques. Electrospinning method was used to produce the support nanofibrous layer using polyvinylidene fluoride-co-hexafluoropropylene (PH) as the polymer and a mixed solvent system of N,N-Dimetylformamide (DMF) and acetone. Afterwards, hydrophobic, functionalized TiO2 nanoparticles were deposited on the surface of the support layer using the electrospraying technique. TiO2 chemical functionalization and their deposition on the support layer were investigated by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy. The... 

The aim of this work is to investigate the effect of molybdenum disulfide on tribological properties of Ultra-high-molecular-weight polyethylene (UHMWPE). UHMWPE/MoS2 nano-composites were prepared using in-situ polymerization and Ziegler-Natta catalytic system. Studies showed that, in order to obtain the optimum tribological properties, interlayer distance between nanosheets should be as high as possible. Therefore, the nanosheets were subjected to oxidation using the required oxidants followed by thermal shock and ultrasound. Fourier-transform infrared spectroscopy (FTIR) analysis was used to determine the formation of functional groups which indicate the formation of S═O bond in the... 

In this research, we report a magnetic pH-sensitive polymeric micelle designed for hydrophobic drug carrier in cancer treatment. This carrier was prepared by self-assembly of biodegradable triblock copolymer PEG-PCL-PEG coated on oleate-modified magnetic nanoparticles. The amphiphilic triblock copolymer was synthesized via reaction between the aldehyde group from the hydrophilic component with the amine group of the hydrophobic component. The resulting Schiff base linkage was sensitive to pH. The structure of nanocarrier was characterized by Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance spectroscopy (1H-NMR). Morphology and size of the magnetic... 

Hyperthermia generally means as increasing the temperature of particular region of body to rise 5 °C above the body's physiological temperature. Here, we investigate the thermal therapy of PEGylated cobalt ferrite nanoparticles prepared by hydrothermal approach on cancerous cell line in the alternative current magnetic field. To characterize of the magnetic nanoparticles (MNPs), scanning electron microscopy, dynamic light scattering, X-ray diffraction, Fourier transform infrared spectroscopy, and vibrating sample magnetometer were used. X-ray diffraction analysis confirmed the spinel phase formation of the MNPs. Cytotoxicity of MNPs using MTT assay on L929 cell lines showed the PEGylated... 

Volatile organic compounds are a major cause of air pollution; therefore, VOCs are a serious fulmination for the environment. According to studies, adsorption processes have a high performance for the removal of pollutants that by selecting the proper absorbent, efficiency will be improved. In this work performance of two metal organic frameworks are studied so porous materials named MIL-101(Cr) and MIL-53(Fe) as an adsorbent for the removal of ethylbenzene have been synthesized hydrothermally. The materials were characterized by Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) analysis, adsorption of ethylbenzene, field emission scanning electron microscopy (FESEM),... 

High performance Fe-Gd-P tri-doped TiO2 nanoparticles (1 at% for each dopant) were successfully synthesized by a modified sol–gel method. Various analytical and spectroscopic techniques were carried out to determine the physicochemical properties of the prepared samples, including XRD, EDX, FESEM, BET, FTIR, XPS, PL, EIS and UV–Vis diffuse reflectance spectroscopy. The photocatalytic activities of prepared samples were evaluated by photo degradation of methyl orange (MO) and 4-chlorophenol (4-CP) as model pollutants under visible light irradiation. Effects of each dopant on different properties of TiO2 nanoparticles were investigated. Results show that Gd and P doping enhances TiO2 surface... 

Microbial contamination poses a serious threat to human health. The evaluation of alternative systems and their reliability for the treatment of water is essential. In this work, a new method for the deposit of more silver nanoparticles (AgNPs) on the external surface of Fe3O4 nanoparticles is presented. Fe3O4 nanoparticles were synthesised by chemical co-precipitation and were modified in two stages using 3-mercaptopropyl trimethoxysilane and grafting allyl glycidyl ether and N, N-dimethylacrylamide. Then, AgNPs were loaded onto the modified Fe3O4 to be used for water disinfection. The resulting nanoparticles were characterised by transmission electron microscopy, X-ray powder diffraction,... 

In the present study, the feasibility of electrospun polyethersolfone (PES) nanofibrous membrane as the solid substrate for microfluidic based immunoassays to enhance the density of immobilized antibody on the surface of membrane was assessed. Conversely, the efficacy of antibody immobilization was compared by two different strategies as 1-Ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC)/N-Hydroxysuccinimide (NHS) coupling chemistry and hydrophobic interaction. Compared to conventional immunoassays carried out in plates or gels, microfluidic based immunoassays grant a lot of advantages such as a consumption of little samples and reagents, shorter analysis time, and higher efficiency.... 

In this work, a nanocomposite containing manganese dioxide (MnO2) modified reduced graphene oxide (rGO) supported bimetallic palladium-nickel (Pd-Ni) catalyst is prepared by electrodeposition method. The nanocomposite modifier film is prepared by forming a thin layer of graphene oxide (GO) via drop-casting of GO nanosheet dispersion on glassy carbon electrode (GCE), followed by electrochemical reduction of the film to provide rGO/GCE. Then, a two-step potential procedure is applied to deposit MnO2 nanoparticles on rGO/GCE. At the optimum deposition conditions, MnO2 nanoparticles with a thickness of 30-50 nm homogeneously covered the rGO surface (MnO2/rGO/GCE). Finally, the bimetallic Pd-Ni... 

A nanocomposite of Ce-doped TiO2-reduced graphene oxide (CedT/RGO) was synthesized to evaluate the synergistic effects of constituents on electrical and photoelectric properties. The nanoparticles of titania and CedT were synthesized via the sol-gel method. Then, RGO was prepared using a new version derived from the Hammer's method and hydrothermal methods. Finally, CedT/RGO nanocomposite was synthesized applying hydrothermal method. The nanoparticles and nanocomposite were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Field emission scanning electron microscopy (FESEM), Energy dispersive X-ray spectroscopy and elemental mapping. Then, diffuse reflectance and... 

In this research pure HA and HA-ZrO2-TiO2 nanocomposite coatings (named HZT coatings) were successfully synthesized by merging two usual electroplating methods. In order to deposit pure HA coating a particular saline solution of Calcium and Phosphate was prepared with pH = 4.2, thermodynamically rich of hydroxyapatite. XRD and FTIR studies prove the synthesis of hydroxyapatite during electrodeposition process. To synthesize composite coatings with rational molar ratios of composite agents to matrix, two different concentrations of ZrO2-TiO2 suspensions were added to Ca-P solution at the pH = 4.2 and electrodeposition process done similar to pure HA sample. XRD, FTIR and FESEM (EDS) analyses... 

Hydroxyapatite (HAp) nanorods with uniform morphology and controllable size were successfully synthesized by precipitating Ca(NO3) 24H2O and (NH4)2HPO4 in the presence of cetyltrimethylammonium bromide (CTAB) and polyethylene glycol 400 (PEG 400) as cationic surfactant and non-ionic cosurfactant, respectively, under hydrothermal conditions. The effect of hydrothermal temperature on the composition, morphology and size of HAp particles was studied using X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR) and scanning electron microscopy (SEM). Results revealed that the morphology and size of HAp particles can be effectively controlled by the presence of CTAB and PEG... 

Hydroxyapatite (HAp) nanostrips were rapidly obtained during a mild microwave heating method. Applying microwave irradiation to Ca(NO3)2·4H2O/CTAB/Na2HPO4 precursor solution, the HAp precipitation process was occurred directly and without common crystallographic transformations including dissolution and slow recrystallization. The cationic surfactant CTAB was used as a soft template to modify nucleation and growth process. TEM investigations showed that the fabricated nanostrips had a width and length of about 10 and 55 nm, respectively. The X-ray diffraction pattern revealed that the fabricated well-crystallized and high purity hydroxyapatite nanostrips had a pattern similar to the bone... 

The synthesis of a novel superabsorbent hydrogel with natural hybrid backbone via graft copolymerization of acrylamide (AAm) onto kappa-carrageenan (kC, as a polysaccharide) and gelatin (as a protein) under classic thermal conditions is described. The Taguchi method as a strong experimental design tool was used for synthesis optimization. A series of hydrogels were synthesized by proposed conditions of Qualitek-4 Software. Considering the results of 9 trials according to analysis of variance (ANOVA), optimum conditions were proposed. The swelling behavior of optimum hydrogel was measured in various solutions with pH values ranging from 1 to 13. In addition, swelling kinetics, swelling in...