Sharif Digital Repository

Hereby, a sonochemical method for synthesis of pure magnetic Fe3O4Onanoparticles (Fe3O4-NPs) in large scale is being introduced. Synthesis proceeds via simple approach, at room temperature, under sonication, using cheap reagents, green antioxidant-reductant reagent and without using inert gas purge as protective atmosphere condition. During this procedure, hydrogen gas releases continuously as valuable byproduct at the anaerobic step of reaction. Characterizations' results indicate that the final product is pure spherical Fe3O4-NPs, with narrow size distribution and about less than 32nm in mean diameter while more than 99% of particles size were less than 40nm. According to Vibrational... 

Polycitric acid was conjugated onto the surface of carbon nanotubes (CNTs), and hybrid nanomaterials containing CNT axis and polycitric acid branches that were highly soluble in aqueous solutions were synthesized. In this work, pristine MWCNTs were opened and functionalized through treatment with acid, then polycitric acid was covalently grafted onto their surface by the "grafting from" approach based on polycondensation of citric acid in the melting state. The chemical structure, morphology, thermal properties and size of MWCNT-g-PCA hybrid materials were investigated by IR, 13C NMR, 1H NMR, TEM, TGA, DSC and DLS. To investigate the biocompatibility of the synthesized hybrid nanomaterials... 

For risk free application of nanoparticles in life science, energy and the environment, it is essential to understand their biological fate and potential toxicity. The application of iron oxide nanoparticles for drug delivery has been one of the most promising researches in the field of nanotechnology. However, there are two major problems associated with magnetically targeted deliveries that still need close attention: • As the drug is coated on to the particle surfaces, there is the possibility of faster drug release (Burst Effect). Therefore, after reaching to the specific site, there is very low amount of drug for delivery. To overcome this problem, some researchers have used conjugation... 

Superparamagnetic iron oxide nanoparticles (SPIONs) are promising materials for various biomedical applications including targeted drug delivery and imaging, hyperthermia, magneto-transfections, gene therapy, stem cell tracking, molecular/cellular tracking, magnetic separation technologies (e.g. rapid DNA sequencing), and detection of liver and lymph node metastases. The most recent applications for SPIONs for early detection of inflammatory, cancer, diabetes and atherosclerosis have also increased their popularity in academia. In order to increase the efficacy of SPIONs in the desired applications, especial surface coating/characteristics are required. The aim of this article is to review... 

Superparamagnetic iron oxide nanoparticles (SPIONs) are promising materials for various biomedical applications including targeted drug delivery and imaging, hyperthermia, magneto-transfections, gene therapy, stem cell tracking, molecular/cellular tracking, magnetic separation technologies (e.g. rapid DNA sequencing), and detection of liver and lymph node metastases. The most recent applications for SPIONs for early detection of inflammatory, cancer, diabetes and atherosclerosis have also increased their popularity in academia. In order to increase the efficacy of SPIONs in the desired applications, especial surface coating/characteristics are required. The aim of this article is to review... 

In the present study, the effect of nanosized graphene oxide layer on thermal stability and biocompatibility of gold nanorods has been examined. The graphene oxide-wrapped gold nanorods were prepared by electrostatic interaction between negatively charged graphene oxide and positively charged nanorods. The resulting nanohybrids were then heated at different time intervals to 95 °C in a water bath to assess the effect of heat on the rods morphology. The structural changes in gold nanorods were monitored via UV-Vis spectroscopy measurements and transmission electron microscopy images. In similar experiments, the graphene oxide used to wrap gold nanorods was reduced by ascorbic acid in a 95 °C... 

In the present study, the effect of nanosized graphene oxide layer on thermal stability and biocompatibility of gold nanorods has been examined. The graphene oxide-wrapped gold nanorods were prepared by electrostatic interaction between negatively charged graphene oxide and positively charged nanorods. The resulting nanohybrids were then heated at different time intervals to 95 °C in a water bath to assess the effect of heat on the rods morphology. The structural changes in gold nanorods were monitored via UV-Vis spectroscopy measurements and transmission electron microscopy images. In similar experiments, the graphene oxide used to wrap gold nanorods was reduced by ascorbic acid in a 95 °C... 

Biocompatibility materials such as Ti6Al4V alloy have many medical applications, but their corrosion resistance and antibacterial properties are low, which limits their medical application. Therefore, to improve these challenges in this study, HAp + 15 wt% TiO2 + 5 wt% Ag nanocomposite coating was applied on Ti6Al4V/TiO2 substrate by sol-gel dip method and sintered at 550 °C. The TiO2 layer was pre-formed on the Ti6Al4V substrate using the gel-sol process. The results showed that the nanocomposite was synthesized correctly, and the particle size was in range of 40–90 nm. The evaluation of the coatings developed showed that TiO2/HAp + 15 wt% TiO2 + 5 wt% Ag coating had higher adhesion... 

Biocompatibility materials such as Ti6Al4V alloy have many medical applications, but their corrosion resistance and antibacterial properties are low, which limits their medical application. Therefore, to improve these challenges in this study, HAp + 15 wt% TiO2 + 5 wt% Ag nanocomposite coating was applied on Ti6Al4V/TiO2 substrate by sol-gel dip method and sintered at 550 °C. The TiO2 layer was pre-formed on the Ti6Al4V substrate using the gel-sol process. The results showed that the nanocomposite was synthesized correctly, and the particle size was in range of 40–90 nm. The evaluation of the coatings developed showed that TiO2/HAp + 15 wt% TiO2 + 5 wt% Ag coating had higher adhesion... 

In this study, conductive sodium alginate/polyaniline/graphene (PAG) NGCs were fabricated utilizing a straightforward solution extrusion method. The 4 point-probe test revealed that the addition of PAG has increased the conductivity of the NGCs up to 9.7 × 10−3 S.cm−1. The results also showed a remarkable increase in the Young modulus and SEM images revealed that the suggested process could produce NGCs continuously and uniformly with desirable porosity. The Fourier-transform infrared spectroscopy spectrum proved a good interaction between PAG and the polymeric matrix. Furthermore, the addition of PAG slightly prevented biodegradation of the NGCs. Finally, the cell viability assay confirmed... 

Asian red ginseng was used for green reduction of chemically exfoliated graphene oxide (GO) into reduced graphene oxide (rGO). The reduction level and electrical conductivity of the ginseng-rGO sheets were comparable to those of hydrazine-rGO ones. Reduction by ginseng resulted in repairing the sp 2 graphitic structure of the rGO, while hydrazine-rGO showed more defects and/or smaller aromatic domains. The ginseng-rGO sheets presented a better stability against aggregation than the hydrazine-rGO ones in an aqueous suspension. Whilst the hydrophobic hydrazine-rGO films exhibited no toxicity against human neural stem cells (hNSCs), the hydrophilic GO and ginseng-rGO films (as more... 

Fontan operation is a final palliative surgical treatment for patients with a single ventricle (SV) physiology. One of the common disadvantages of Fontan operation is to generate a non-pulsatile flow instead of the normal pulsatile flow produced by contraction of the ventricle. Theoretically, in SV patients, maintaining the antegrade flow through pulmonary valve can produce flow pulsatility in the right and left pulmonary arteries. However, it not only increases the energy loss in the Fontan of total cavopulmonary pathway (TCPC), but also imposes an extra load on pulmonary arteries as well as the ventricle. In this study, the potential capability of pulmonary valve of the patient that can be... 

In the present study, a detailed biocompatibility testing of a novel class of hybrid nanostructure based on hyperbranched polyglycerol and β-cyclodextrin is conducted. This highly water soluble nanostructure with size of less than 10 nm, polydispersity of less than 1.3, chemical tenability and highly branched architecture with the control over branching structure could be potentially used as a carrier in drug delivery systems. To this end, extensive studies in vitro and in vivo conditions have to be demonstrated. The in vitro studies include in vitro cytotoxicity tests; MTT and Neutral Red assay as an indicator of mitochondrial and lysosomal function, and blood biocompatibility tests such as... 

In this study, a semi-conductive nanocomposite for electrically controlled drug delivery is introduced. Hydrolyzed collagen known as a naturally abundant polypeptide was modified with polycaprolactone. This modification changed the mechanical properties of the hydrolyzed-collagen. A hydrogel compound was synthesized through radical co-polymerization of acrylic acid on the backbone of this biocompatible polymer in the presence of a crosslinker. The reaction parameters affecting the water absorbency of the hydrogel were optimized using Taguchi method. In situ polymerization of aniline, incorporated conductive nanofiber pathways throughout the hydrogel matrix. 1H NMR, TGA, AFM, SEM, FTIR,... 

Highly conductive polypyrrole/graphene (PYG) nanocomposite was synthesized with chemical oxidation process via emulsion polymerization and used for the preparation of novel porous conductive gelatin/chitosan-based scaffolds. The effect of PYG loading on various properties of scaffolds was investigated. The obtained results indicated that by introducing PYG into the polymeric matrix, the porosity and swelling capacity decreased while electrical conductivity and Young's modulus demonstrated increasing trend. The in vitro biodegradation test revealed that pure gelatin/chitosan matrix lost 80% of its weight after six weeks in the presence of lysozyme whilst the biodegradation rate was...