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Influence of the supramolecular arrangement of iron phthalocyanine thin films on catecholamine oxidation
摘要： The versatility of iron phthalocyanine (FePc) to form distinct supramolecular arrangements in thin films, characterized by their thickness, molecular organization, morphology, and crystallinity, can be used to tune the electrochemical oxidation of catecholamines, becoming a promising material for sensing applications. Here, Langmuir-Schaefer (LS) and electrodeposition (ED) techniques have been used to produce thin films of FePc with different supramolecular arrangements on ITO electrodes. Both types of modified electrode were evaluated for the electrochemical oxidation of L-Dopa, dopamine (DA), norepinephrine (NEp), and epinephrine (Ep) in aqueous solution. The effect of scan rate, potential range, presence of oxygen, and pH were also evaluated, having an influence on the electrochemical oxidation of catecholamines. The FePc/ED modified electrodes showed two distinct peaks in the presence of mixtures of DA/L-Dopa and DA/Ep, while for FePc/LS modified electrodes an overlap of the oxidation waves was observed. This behaviour reveals the influence of the supramolecular arrangement of FePc on catecholamine oxidation. The FePc/LS modified electrodes showed a limit of detection of 0.024 μmol L-1 for DA and 0.168 μmol L-1 for L-Dopa, while FePc/ED showed limits of detection of 0.288 μmol L-1 and 0.564 μmol L-1, respectively. The FePc films showed suitable properties for future application as catecholamine sensors.
关键词： electrodeposition,Langmuir-Schaefer,iron phthalocyanine,catecholamines
更新于2025-09-23 15:23:52
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Laser synthesis of iron nanoparticle for Fe doped hydroxyapatite coatings
摘要： Thin films of iron doped hydroxyapatite have been prepared by nanosecond Pulsed Laser Deposition (PLD). The composite target used for the deposition has been obtained by mixing commercial hydroxyapatite powder with iron-based nanoparticles produced by femtosecond laser ablation in liquid (LAL) (4% of iron nanoparticles). In fact, LAL technique allows to obtain metallic nanostructures without any toxic chemicals and reagents, with a green approach that is crucial for application in biological and medical technologies. Films have been prepared with substrate temperature growing from room temperature (RT) to 500 °C. The effect of deposition temperature on morphology, composition and structural properties of coatings has been investigated. Films deposited at higher temperature result dense and crystalline, they present microscale and nanoscale structures, an average surface roughness of 0.3 μm and magnetic properties suitable for biomedical applications.
关键词： PLD,Iron doped hydroxyapatite,Laser ablation in liquid,Regenerative orthopedic applications
更新于2025-09-23 15:23:52
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Novel Iron-oxide Catalyzed CNT Formation on Semiconductor Silicon Nanowire
摘要： An aqueous ferric nitrate nonahydrate (Fe(NO3)3.9H2O) and magnesium oxide (MgO) were mixed and deposited on silicon nanowires (SiNWs), the carbon nanotubes (CNTs) formed by the concentration of Fe3O4/MgO catalysts with the mole ratio set at 0.15:9.85 and 600°C had diameter between 15.23 to 90nm with high-density distribution of CNT while those with the mole ratio set at 0.45:9.55 and 730°C had diameter of 100 to 230nm. The UV/Vis/NIR and FT-IR spectroscopes clearly confirmed the presence of the silicon-CNTs hybrid structure. UV/Vis/NIR, FT-IR spectra and FE-SEM images confirmed the silicon-CNT structure exists with diameters ranging between 15-230nm. Thus, the study demonstrated cost effective method of silicon-CNT composite nanowire formation via Iron-oxide Catalyze synthesis.
关键词： SiNWs,iron-oxide catalyze,silicon-CNT structure,hybrid structure,High-density
更新于2025-09-23 15:23:52
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A Production-Accessible Method: Spectrophotometric Iron Speciation in Wine Using Ferrozine and Ethylenediaminetetraacetic Acid
摘要： Wine oxidation is reported to be linked to the iron species present in the wine, but spectrophotometric speciation is plagued by unstable measurements due to alterations to the reduction potential of iron by complexing agents. Ferrozine raises the reduction potential of iron by complexing preferentially to iron(II), inducing the reduction of iron(III) during analysis; here, EDTA is added to chelate iron(III) and to stabilize the forms of iron. Bisulfite addition allows the use of ferrozine for red wine analysis by mitigating color interference. Measurements agree with values from a previous method for iron(II) and from FAAS for total iron. Spike recoveries were in the range of 103.5?110.1%. The method is linear for iron concentrations in the range of 0.10?6.00 mg L?1 and offers good precision (CV 0.4?10.1%) and low limits of detection (0.02 mg L?1) and quantification (0.06 mg L?1). The method demonstrated changes to iron speciation during the oxygenation of red wines.
关键词： reduction potential,oxidation,wine,spectrophotometry,ferrozine,iron speciation
更新于2025-09-23 15:23:52
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Fe-N3/C active catalytic sites for the oxygen reduction reaction prepared with molecular level geometry control via covalent immobilization of iron-terpyridine motif onto carbon
摘要： A model for a non-precious metal catalyst for the oxygen reduction reaction (ORR) in aqueous media has been prepared by functionalizing a commercial Vulcan XC-72 carbon support with a terpyridine-based nitrogenous ligand. The terpyridine ligand geometry allows the formation of active catalytic sites by selectively embedding an N3/C structural motif into the carbon support confirmed by thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) measurements. Room temperature metal-ligand coordination results in desired Fe-N3/C moieties on the surface. This model system was used to demonstrate catalytic activity of the surfaces containing mainly Fe-N3 sites for ORR in acidic and basic media. Importantly, we demonstrate that the system could be prepared at mild reaction conditions, does not require high-temperature treatments, and shows catalytic activity for ORR. Interestingly, when the system was pyrolyzed in an N2 atmosphere at 700?C, the resulting activity declined. The non-heat-treated Fe-N3/C surface demonstrates comparable activity in acidic electrolyte medium when compared to most literature catalysts that are typically heat treated to produce four nitrogen’s coordinated to one iron center (Fe-N2+2/C). Interestingly, despite the fact that many systems reported so far in the literature exhibit enhanced activity after heat treatment, our system showed an increase in activity when the material was not pyrolyzed.
关键词： catalyst,oxygen reduction reaction,nitrogen,iron,non-precious metal
更新于2025-09-23 15:22:29
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Second Derivative Spectrophotometric Determination of Iron(II) and Ruthenium(III) Using 1, 10-phenanthroline
摘要： A simple and sensitive derivative spectrophotometric method has been developed for the determination of Fe(II) and Ru(III) using the baseline to peak measurement techniques. In the present method 1,10-phenanthroline (o-phen) used as a complexing agent. Fe(II) and Ru(III) forms a complex with o-phen at pH 5 and 4, respectively. Based on baseline-to-peak measurement techniques deep red Fe(II)-o-phen complex shows the maximum peak at 535 nm, while the yellow product of Ru(II) - o-phen complex at 466 nm. Beer’s law obeyed in the range of 0.1 - 2.0 μg mL-1 for Fe(II) and 5.0 - 20.0 μg mL-1 for Ru(III) which is supported by correlation coefficient 0.99853 and 0.99914, respectively. The present method has been applied successfully for the determination of Fe (II) in pharmaceutical formulations and Ru(III) in some synthetic mixtures.
关键词： Iron(II),Second Derivative Spectra,Ruthenium(III),1,10-Phenanthroline
更新于2025-09-23 15:22:29
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Light Transmission of Glasses Synthesized on the Basis of Quartz Sand of Different Deposits
摘要： Container and sheet glass are synthesized from various batches with the equivalent addition of complexing decolorizers. The effect of ceria and potassium nitrate on the light transmission coefficient is investigated. Measurement of optical characteristics of the glasses shows that light transmittance increases up to 90–93% (λ = 500–750 nm). It is determined that an increase in the concentration of ceria and potassium nitrate up to particular values in the case of each composition results in the increase in hydrolytic stability, TLCE, and the light transmission coefficient.
关键词： discoloration,iron oxide,light transmission coefficient,chemical stability,quartz sand,synthesis of glass,raw materials
更新于2025-09-23 15:22:29
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In vivo MRI assessment of bioactive magnetic iron oxide/human serum albumin nanoparticle delivery into the posterior segment of the eye in a rat model of retinal degeneration
摘要： Background: Retinal degeneration diseases affect millions of patients worldwide and lead to incurable vision loss. These diseases are caused by pathologies in the retina and underlying choroid, located in the back of the eye. One of the major challenges in the development of treatments for these blinding diseases is the safe and efficient delivery of therapeutics into the back of the eye. Previous studies demonstrated that narrow size distribution core–shell near infra-red fluorescent iron oxide (IO) nanoparticles (NPs) coated with human serum albumin (HSA, IO/HSA NPs) increase the half-life of conjugated therapeutic factors, suggesting they may be used for sustained release of therapeutics. In the present study, the in vivo tracking by MRI and the long term safety of IO/HSA NPs delivery into the suprachoroid of a rat model of retinal degeneration were assessed. Results: Twenty-five Royal College of Surgeons (RCS) pigmented rats received suprachoroidal injection of 20-nm IO/HSA NPs into the right eye. The left eye was not injected and used as control. Animals were examined by magnetic resonance imaging (MRI), electroretinogram (ERG) and histology up to 30 weeks following injection. IO/HSA NPs were detected in the back part of the rats’ eyes up to 30 weeks following injection by MRI, and up to 6 weeks by histology. No significant differences in retinal structure and function were observed between injected and non-injected eyes. There was no significant difference in the weight of IO/HSA NP-injected animals compared to non-injected rats. Conclusions: MRI could track the nanoparticles in the posterior segment of the injected eyes demonstrating their long-term persistence, and highlighting the possible use of MRI for translational studies in animals and in future clinical studies. Suprachoroidal injection of IO/HSA NPs showed no sign of adverse effects on retinal structure and function in a rat model of retinal degeneration, suggesting that suprachoroidal delivery of IO/HSA NPs is safe and that these NPs may be used in future translational and clinical studies for extended release drug delivery at the back of the eye.
关键词： Retinal degeneration,Suprachoroidal injection,RCS rats,Iron oxide nanoparticles
更新于2025-09-23 15:22:29
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Ordered assemblies of Fe3O4 and a donor-acceptor-type π-conjugated polymer in nanoparticles for enhanced photoacoustic and magnetic effects
摘要： We report that the ordered structure in the assemblies of iron oxide nanoparticles in conjugated polymer nanoparticles is the key to achieve better properties to realize multimodal theranostic agents for magnetic resonance and photoacoustic imaging. Hybrid nanoparticles of a conjugated polymer (PCPDTBT), a phospholipid (D8PE) with a primary amine polar head, and iron oxide (Fe3O4) nanoparticles were prepared by a phase-separated film shattering process by varying the iron oxide concentration while maintaining a fixed mixing ratio of PCPDTBT and D8PE. Notably, the hybrid nanoparticles assembled at a molar mixing ratio of 1:1:0.8 (PCPDTBT/D8PE/Fe3O4) exhibited the shortest transversal relaxation time, T2, and a photoacoustic signal 22 times higher than that obtained at the 1:1:0 mixing ratio. Structural analysis by X-ray diffraction together with the measurements of energy transfer by transient absorption spectroscopy confirmed that the structural ordering of these hybrid nanoparticles was responsible for their enhanced photoacoustic and magnetic properties.
关键词： Conjugated polymers,Photoacoustic imaging,Magnetic resonance imaging,Iron oxides,Hybrid nanoparticles
更新于2025-09-23 15:22:29
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Facile Sol-gel Synthesis of Metaloxide Nanoparticles in a Cellulose Paper Template
摘要： Ensembles of free standing particles of titanium, zinc, copper and iron oxides of 6-109 nm in size were sol-gel synthesized with a use of a cellulose paper as a template. The calcination time as short as 60 min at 550°C in air was found to be sufficient for the formation of crystalline single phase TiO2 or ZnO nanoparticles, Cu2O+CuO or Fe2O3+Fe3O4 nanocomposites and to burn out the organic components. The impurities initially present in the cellulose (Сa, Na, Cl) were detected in the synthesized compounds.
关键词： Sol-gel synthesis,Zinc oxide,Nanoparticle,Copper oxides,Cellulose,Iron oxides,Titanium oxide
更新于2025-09-23 15:22:29