Sharif Digital Repository

Unique physiochemical and biological properties of nanofibers along with the choice of a wide variety of materials for both fabrication and tunable release patterns make nanofibers an ideal option for drug delivery. Loading antibacterial agents into nanofibers has attracted great deal of attention. Whilst there are several studies focusing on applying new generations of antibacterial materials, antibiotics are still the gold standard in clinical applications. Therefore, we aimed at introducing antibiotic-loaded nanofiber substrates with potential for topical skin delivery applications, reduced consumption of antibiotics and increased storage time. We applied Amoxicillin (AMX) as a model drug... 

In this contribution, the effect of physical immobilization of methylene blue (MB) into silica nanocomposites was investigated on the conversion and selectivity of the photooxygenation of anthracene and dihydroartemisinic acid (DHAA). Physically immobilized photocatalysts were synthesized through a developed Stöber method and were thoroughly characterized by UV–Vis, FTIR, XRD, XPS, SEM, TEM, HR-TEM, BET-BJH, and EDX analyses. Based on the TEM and UV–Vis results, it was determined that enhancement of the MB concentration as an organocatalyst for the Stöber reaction led to an increase in the size of the nanoparticles from 54 to 183 nm and a 21 nm blue shift in their UV–Vis spectra. Moreover,... 

Gadolinium (Gd) and cobalt (Co) substituted Sr–Ba–Cu-based Y-type hexaferrites were synthesized with the help of the sol–gel auto-combustion route. XRD (X-ray diffraction) analysis was done to ratify the phase formation of hexaferrites. The impact of Gd3+ substitutions was measured on all the lattice parameters. Lattice constants “a” and “c” were found between 5.879–5.891 Å and 43.185–43.620 Å, respectively. It was observed from the XRD analysis that with an increase in Gd–Co contents, the enhancement in the average crystallite size is noted. The thermal decomposition process was studied using TGA (thermogravimetric analysis), revealing that the precursor may give the ending product when... 

Landfill leachate is a highly contaminated liquid generated in municipal solid waste landfills. The application of sulfate radical-based advanced oxidation processes (SR-AOP) in landfill leachate treatments is emerging due to their ability to degrade both organic refractory matters and ammonia nitrogen. In this paper, application of peroxymonosulfate (PMS), activated by Fe2+ and UV was used as an economical and environmentally friendly approach for treatment of landfill leachate. Chemical oxygen demand (COD) and ammonia removals were measured as the two primary responses of landfill leachate to UV/PMS/Fe2+ treatment system. The main parameters (pH, PMS/Fe2+ mass ratio, Fe2+ dosage) affecting... 

Hyperbranched polyethyleneimine functionalized silica (PEI-SiO2) nanoparticles with considerable hydrophilicity were synthesized and incorporated into a polysulfone (PSF)/dimethylacetamide (DMA)/polyvinylpyrrolidone (PVP) membrane casting solution in five different ratios to fabricate PEI-SiO2/PSF nanocomposite membranes using nonsolvent-induced phase separation. The hydrophilic PEI-SiO2 nanoparticles were characterized by TEM, FTIR, TGA, and XPS analyses. Morphology, water contact angles, mean pore sizes, overall porosity, tensile strengths, water flux, antifouling and the dye separation performances of the PEI-SiO2/PSF membranes were also studied. The PEI-SiO2 nanoparticles were uniformly... 

We introduce highly antifouling Polymer-Nanoparticle-Nanoparticle/Polymer (PNNP) hybrid membranes as multi-functional materials for versatile purification of wastewater. Nitrogen-rich polyethylenimine (PEI)-functionalized halloysite nanotube (HNT-SiO2-PEI) nanoparticles were developed and embedded in polyvinyl chloride (PVC) membranes for protein and dye filtration. Bulk and surface characteristics of the resulting HNT-SiO2-PEI nanocomposites were determined using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). Moreover, microstructure and... 

Lung cancer (LC) is the leading cause of cancer mortality so, the analysis of exhaled human breath has great significance for early non-invasive diagnosis. Poor selectivity and strong humidity are two bottlenecks for the application of gas sensors to exhaled breath analysis. The development of novel extractive phases for the analysis of exhaled breath by chromatography is therefore a lucrative object. Polyhedral oligomeric silsesquioxanes (POSS) are among the 3D porous materials whose unique properties make them promising coatings for solid-phase microextraction (SPME). Selective enrichment of polar or nonpolar targets depends on the pore size and functional groups on the POSSs. Herein, we... 

Herein, two distinct nanocomposites of CaTiO3 micro-cubes and polygonal SrFe12O19, both decorated with NiO nanoparticles, were successfully synthesized using hydrothermal method. The physico-chemical features of as-prepared samples were evaluated via XRD, FTIR, UV–vis, BET, XPS, FESEM and EDS analysis. Microwave attenuation features of as-prepared single layer absorbers were determined by VNA analysis in 2–18 GHz. Simulation confirmation was checked by preparing a bi-layer samples and evaluating it using VNA analysis after finding the appropriate thickness of each layer. The reflection loss from each single layer samples containing 20 wt% of each CaTiO3/NiO and SrFe12O19/NiO nanocomposites... 

An efficient and selective drug delivery vehicle for cancer cells can remarkably improve therapeutic approaches. In this study, we focused on the synthesis and characterization of magnetic Ni1−x Cox Fe2 O4 nanoparticles (NPs) coated with two layers of methionine and polyethylene glycol to increase the loading capacity and lower toxicity to serve as an efficient drug car-rier. Ni1−x Cox Fe2 O4 @Methionine@PEG NPs were synthesized by a reflux method then charac-terized by FTIR, XRD, FESEM, TEM, and VSM. Naproxen was used as a model drug and its loading and release in the vehicles were evaluated. The results for loading efficiency showed 1 mg of Ni1−x Cox Fe2 O4 @Methionine@PEG NPs could load... 

In this research, a green solid catalyst of phosphomolybdic acid (HPA) prated on Chitosan was synthesized to produce biodiesel. The prepared catalyst was characterized using Fourier Transform Infrared spectroscopy (FTIR), Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-Ray (EDX), X-ray diffraction (XRD), and XRF analyses. The catalyst was applied in microwave-assisted trans-esterification of Pomegranate oil, and the biodiesel production process was optimized by response surface methodology based on central composite design (RSM-CCD). The effect of influential reaction parameters, including time (33–142 min), catalyst weight (0.15–5.6 wt%), and methanol to oil molar... 

An economical epichlorohydrin cross-linked chitosan @ magnetic Fe3O4/activated carbon nanocomposite, CH-EP@Fe3O4/AC, was successfully synthesized and used as a suitable adsorbent material for removal of a triphenylmethane cationic dye, Malachite green (MG), an anionic dye, Reactive red 120 (RR120), and Mercury ions (Hg2+) from aqueous solution. The prepared adsorbent has been characterized with Fourier transform infrared spectroscopy, X-ray diffraction, Scanning electron microscopy, Thermogravimetric analysis, Brunauer–Emmett–Teller analysis as well as Vibrating sample magnetometer. According to the result of Brunauer–Emmett–Teller isotherm, the prepared adsorbent has a specific surface area... 

The most common reasons for hard-tissue implant failure are structural loosening and prosthetic infections. Hence, in this study, to overcome the first problem, different bioinspired coatings, including dual acid-etched, anodic TiO2 nanotubes array, anodic hierarchical titanium oxide (HO), micro- and nanostructured hydroxyapatite (HA) layers, and HA/chitosan (HA/CS) nanocomposite, were applied to the titanium alloy surfaces. X-ray diffraction and FTIR analysis demonstrated that the in situ HA/CS nanocomposite formed successfully. The MTT assay showed that all samples had excellent cell viability, with cell proliferation rates ranging from 120% to 150% after 10 days. The HO coating... 

This work suggests a green method for synthesizing Au nanoparticles (AuNPs) using the aqueous extract of Salix aegyptiaca extract. The mechanism of green synthesized AuNPs was examined by molecular electrostatic potential (MEP) calculations. AuNPs were characterized with different techniques such as Ultraviolet–visible spectroscopy (UV–vis), Fourier-transform infrared spectroscopy (FT-IR) spectroscopy, X-ray diffraction (XRD), and Transmission electron microscopy (TEM). Electrochemical investigation of modified glassy carbon electrode using AuNPs (AuNPs/GCE) shows that the electronic transmission rate between the modified electrode and [Fe (CN)6]3−/4− increased. Process of oxidation, energy... 

Systemic chemotherapy has lost its position to treat cancer over the past years mainly due to drug resistance, side effects, and limited survival ratio. Among a plethora of local drug delivery systems to solve this issue, the combinatorial strategy of chemo-hyperthermia has recently received attention. Herein we developed a magneto-thermal nanocarrier consisted of superparamagnetic iron oxide nanoparticles (SPIONs) coated by a blend formulation of a three-block copolymer Pluronic F127 and F68 on the oleic acid (OA) in which Curcumin as a natural and chemical anti-cancer agent was loaded. The subsequent nanocarrier SPION@OA-F127/F68-Cur was designed with a controlled gelation temperature of... 

Methicillin resistance Staphylococcus aureus bacteria (MRSA) are serious hazards of bone implants. The present study was aimed to use the potential synergistic effects of Melittin and tetracycline to prevent MRSA associated bone implant infection. Chitosan/bioactive glass nanoparticles/tetracycline composite coatings were deposited on hydrothermally etched titanium substrate. Melittin was then coated on composite coatings by drop casting method. The surfaces were analyzed by FTIR, XRD, and SEM instruments. Tetracycline in coatings revealed multifunctional behaviors include bone regeneration and antibacterial activity. Releasing ALP enzyme from MC3T3 cells increased by tetracycline, so it is... 

Simvastatin, a well-known antihyperlipidemic drug, has antibacterial activity against a broad range of bacteria, especially Staphylococcus aureus. In present study, a nanoemulsion gel-based formulation containing Simvastatin was developed for infected wound therapy. Therefore, different formulations of Simvastatin nanoemulsion were prepared. Based on droplet size, polydispersity index and zeta potential, the best nanoemulsion formulation containing Simvastatin was selected for development of nanoemulsion gel formulation of drug using carbomer 934 as gelling agent. Thermodynamic stability of Simvastatin nanoemulsion was assessed at different conditions. The in vitro antibacterial activity... 

The biodegradation behavior of Mg, coated by polymethyl methacrylate as well as polymethyl methacrylate (PMMA)−bioactive glass (BG) composite was investigated. Electrophoretic deposition and dip coating techniques were adopted to prepare composite coating using a suspension of different percentages of the above two chemical materials. The deposited coatings were characterized using SEM, EDS, FTIR, and water contact angle measurements. Biodegradation behavior study of the coated Mg was performed using linear polarization, impedance spectroscopy, and immersion tests in simulated body fluid. The compact and homogeneous composite coating was developed as evidenced by electron microscopy results.... 

Introduction. Dental caries is the most common cause of tooth loss. However, it can be stopped by enhancing remineralization. Fluoride and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) are among the most important remineralizing agents. Recent studies have used bioactive glass as a remineralizing agent in different forms. This study aimed to assess the efficacy of a composite paste (prepared by mixing urethane polypropylene glycol oligomer with bioactive glass powder for easier application). Materials and Methods. Enamel disks were cut out of the buccal surface of extracted sound third molars. The samples were randomly divided into 3 groups of 15 and underwent Vickers... 

The core-shell nanofibers, produced by the coaxial electrospinning method, are good candidates for delivery of anticancer drugs due to their continuous release without initial burst release. In this work, the N-carboxymethyl chitosan (N-CMCS)-polyvinyl alcohol (PVA)/poly(ε-caprolactone) (PCL) composite and core-shell nanofibers were prepared by two-nozzle and coaxial electrospinning techniques, respectively. Doxorubicin (DOX) as an anticancer drug was loaded into the N-CMCS/PVA/PCL nanofibers fabricated by two-nozzle and coaxial electrospinning. The performance of nanofibers was compared for the adsorption and controlled release of DOX against MCF-7 breast cancer cells death in vitro. The... 

Co–Zr doped Ni ferrite substituted polyaniline (PANI) nanocomposites were prepared using polymerization reaction method. NiFeCo0.5Zr0.5O4 with 12.5%, 25%, 37.5% and 50% PANI (A1, A2, A3 and A4) were used to obtain better photocatalytic efficiency. XRD, UV/VIS, BET, and FESEM were employed to characterize the PANI/ferrite nanocomposites. The effect of reaction time and nanoparticle concentrations on the photocatalytic degradation were thoroughly evaluated. XRD analysis confirmed the phase of NiFeCo0·5Zr0·5O4ferrite, while FESEM analysis was performed to investigate the surface morphology of the nanocomposites. The crystallinity was increased with the Co–Zr doped Ni ferrite contents in the...