access deny [1301]
Research field: Nanomaterials for medical application such as diagnosis and drug delivery
Expert: Mr. Ourangi
Phone: 021-82883917
Address: No. 251, East 2nd Floor, Block 3
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Magnetic nanoparticles development is an intense subject in various biomedical applications. Among these applications, magnetic nanoparticles as contrast agents are of special interest for improving the diagnostic accuracy of magnetic resonance imaging (MRI). We report here the synthesis of magnetic iron carbide nanoparticles and their stabilization in aqueous media. The challenge of achieving phase transfer of hydrophobic iron carbide nanoparticles to hydrophilic media was addressed by silica shell. Silica coated iron carbide nanoparticles were fabricated with both mesoporous and dense silica shells followed by investigating the impact of such a coating on their performance as T2‐negative contrast agents in MRI. The crystalline structur
Synthesis and utilization of nanostructures exhibiting both magnetic and plasmonic characteristics have been considered significantly important. In this research, 12-nm iron nanoparticles were first synthesized by the electric arc discharge procedure. Gold nanoparticles were then synthesized via the chemical reduction of gold salt which were used to cover magnetic nanoparticles uniformly. X-ray powder diffraction, scanning and transmission electron microscopies, and UV–Vis spectroscopy were implemented to determine available phases, particles sizes, the morphology of nanoparticles and optical characteristics. Surface plasmon resonance behavior appeared at nm for iron-based@ gold nanoparticles. Vibrating sample magnetometry of iron nanopar
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Bismuth based rod-like nanostructures were prepared via oriented attachment of colloidal bismuth based nanoparticles synthesized by direct current (DC) arc discharge in liquid. For the synthesis of bismuth based nanoparticles 5 A and 20 A DC electrical currents were applied between two pure bismuth electrodes in water. Bismuth based nanoparticles extracted from the water after 30 days then dispersed in ethanol. Bismuth based rod-like nanostructures formed via the oriented attachment mechanism in ethanol during 30 days. According to X-ray diffraction (XRD) patterns of as-prepared samples, the main parts of the particles were bismuth phase while after 30 days bismuth oxide and bismuth hydroxide phases were dominant. To investigate the spe
A green precipitation method has been used for the synthesis of ultra‐small APTMS‐mPEG conjugated Mn3O4 nanoparticles. Spherical cores in the uniform size of 4?1 nm were characterized by HRTEM. Zeta potential of −45 mV and the invariant turbidimetry results during the time, confirmed super‐stability of the colloids. MRI relaxometry by 1.5 T scanner represented two values of r1= 8.23 s−1mM−1 and r1=7.3 s−1mM−1 for diluted and concentrated samples. The r2/r1 ratio was also decreased from 11.86 to 6.9 by dilution of colloids. Particle aggregation and motional narrowing phenomena led to a dual T1/T2 contrast agent in the Mn ion concentrations of more than 0.2 mM. The optimum concentration of Mn ion for maximum dual si
Commercial contrast agents demonstrated release risk of the toxic gadolinium ions, and designing of highly stable complexes of biogenic element such as Mn is challenging. In this contribution, Mn‐melanin nanoparticles have been prepared and reacted with m‐PEG. The effect of initial amount of Mn ions on the Mn absorption and its release by melanin nanoparticles (MNP) has been investigated. It has been found that MNP absorb and release more Mn ion by increasing the initial amount of Mn ions. It has been found that time and temperature has no significant effect on Mn absorption by MNP. It is found that the hydrodynamic size of MNP is in accordance with size of MNP which measured with TEM analysis (5.5?2 nm) and the effect of chain of m?
Background: Candida albicans as an opportunistic fungus is one of the most important causes of late-onset morbidity and mortality in patients with major burns and severely impaired immune system. In recent years, the emergence of resistance to opportunistic fungi and toxicity of antimicrobial drugs make it necessary to develop new drugs.Methods: In the present study, we investigated anticandidal effects of indolicidin, as a representative of host defense peptide, conjugated with gold nanoparticles in fluconazole-resistant clinical isolates of C. albicans. After characterizing the conjugation of indolicidin using biophysical methodologies, the cytotoxicity and hemolytic activity of the nanocomplex were examined. In addition, the expression l
Candida albicans (C. albicans) belongs to the opportunistic fungal pathogens, which cause a wide spectrum of infections in immune-compromised patients. Graphene oxide (GO), a biocompatibility agent, has been reported to exhibit effective antimicrobial activity. In the present study, a graphene oxide/fluconazole (GO/Flu) compound was synthesized and characterized using Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. The antifungal activity of GO/Flu was examined against fluconazole-resistant C. albicans (ATCC 10231) compared to GO and Flu using the broth microdilution method, according to CLSI protocol. DNA fragmentation was assessed through the antifungal mechanism of GO/Flu. The release of Fluin PBS medium was measur
BackgroundThe pentavalent antimonial compounds are the first drug of choice for leishmania infection, but have several side effects that cause some restriction for use. Extension of nanoparticle use in biological research and proven effectiveness of manganese nanoparticles on fungi and bacteria, along with the lack of information about its antileishmanial effects, have motivated this study. Manganese can induce cell apoptosis by increasing FOXO3a-Bim/PUMA mRNA activation and activating of caspase-3 pathway.MethodsThis study was aimed to examine the efficacy of manganese oxide nanoparticles againstLeishmania major (MRHO/IR/75/ER) in vitro and in vivo. To evaluate the antileishmanial activity of NPs, light microscopic observation was used to
In this research, the Curie temperature of gadolinium Gd nanostructures with shapes of nanoparticle, nanorod, and thin film were simulated based on the Monte Carlo algorithm via Vampire software. Curie temperature of Gd nanoparticles decreases from 289 K to 245 K by reducing the diameter size of Gd nanoparticle from 10 nm to 1 nm. It has been observed that with constant aspect ratio and also in constant length, the Curie temperature of Gd nanorod increase by increasing the nanorod diameter. In addition, the Curie temperature increases by increasing the thickness of Gd thin film. Finally, results of this simulation are fitted on proposed equations by other researcher to extract their corresponding constants.
Colloidal Bi/Bi2O3 nanoparticles were synthesized by pulsed Nd:YAG laser ablation of metallic bismuth target. Structural characterization and optical properties of Bi/Bi2O3 nanoparticles have been studied. Moreover mechanism of nanoparticles formation and oxidation of Bi nanoparticles were proposed, according to experimental data from UV–vis spectroscopy and calculation of optical properties. SEM and XRD analyses indicate the formation of Bi2O3 nanoparticles with mean size of 27???4?nm which are mixing of four phases including rhombohedra crystal structure of Bi, Bi(OH)3, monoclinic α-Bi2O3 and tetragonal β-Bi2O3. In addition, optical extinction of Bi2O3 nanoparticles can be fine-tuned in the visible spectral region by tailoring the oxi
Band gap tunable cadmium selenide (CdSe) quantum dots (QDs) were synthesized within earthworms that emit in the middle of the visible spectrum. We demonstrated that this luminescence emission is a combination of the earthworm's protein and QD luminescence, such that the contribution of QDs in the luminescence was negligible. Eisenia fetida earthworms were used for QD biosynthesis and were exposed to different concentrations of CdCl2 and Na2SeO3 in standard soil for an adequate exposure time. The size of the CdSe QDs based on the effective mass model was in agreement with the size measured from the transmission electron microscopy analysis, with an average diameter of 7?nm. Ultraviolet–visible and photoluminescence analyses confirmed the
Facile preparation of biocompatible nano‐platforms for computed tomography (CT) is demanding. In this work, PEGylated melanin nanoparticles (MNPs) are prepared and reacted with barium ions as CT imaging contrast agent (Ba‐MNPs‐mPEG). It is found that the hydrodynamic size of MNPs is in accordance with size of MNPs measured by electron microscopy (4?1 nm). The zeta potential of MNPs reduces by PEGylation and chelating with Ba2+ ions. Fourier transformed infrared (FTIR) analysis proposed that OH and NH groups of MNPs are possible binding sites for Ba2+ ions. The prepared Ba‐MNPs‐mPEG shows no significant cytotoxicity at concentration up to 100 ppm of barium concentration after 24 h. Finally, our results indicated that the X??
In this study, Bi2O3 nanoparticles were employed as computed tomography (CT) contrast agents. In this regard, X-ray attenuation of Bi2O3 nanoparticles, prepared via DC arc discharge in water, was investigated. In addition, the optical, structural, morphology and cytotoxicity properties of afforded nanoparticles were also studied. The electric arc discharge was done via bismuth electrodes in a water medium. Then, to stabilise Bi2O3 nanoparticles, chitosan molecule was cross linked via glutaraldehyde around Bi2O3 nanoparticles. X-ray diffraction analysis demonstrated the monoclinic structure and field emission-scanning electron microscopy images clarified the average size of Bi2O3 as 40 nm. Fourier transform infrared analysis proved chitosan
A new strategy for water-dispersibility of hydrophobic carbide nanostructures was proposed. In this regard, hydrophobic Fe 5 C 2 nanoparticles (NPs) with size ranging 25–40 nm were synthesized and coated with 12–15 nm silica shell for biomedical applications. X-ray diffraction (XRD) results revealed that Fe 5 C 2 NPs with monoclinic structure were successfully prepared. The crystalline structure of Fe 5 C 2 NPs was remained unchanged and saturation magnetization of core remained nearly constant after coating with silica shell. Moreover, Raman spectroscopy identified D-band of amorphous carbon shells which was also confirmed by transmission electron microscopy (TEM). Finally, Fe 5 C 2@ SiO 2 core@ shell NPs demonstrated no significant cy