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Kiwi extract (KE) including different components such as quercetin, vitamins C and E, and actinides has been known as a debridement agent for burn wounds. In this study, electrospun poly(ɛ-caprolactone)/cellulose acetate blend nanofibers incorporating KE (PCL/CA/KE) were prepared and their performance was evaluated for healing acceleration of burn wounds. The physicochemical characterization of PCL/CA/KE nanofibers showed an average diameter of ∼420 nm, porosity of 70%, water contact angle of 61°, and water uptake of ∼220%. Moreover, the continuous release trend of KE from PCL/CA blend nanofibers happened during 24 h and the release mechanism was governed by the Fickian diffusion. Besides the cytocompatibility of PCL/CA/KE nanofibers, their in vivo experiments revealed that the bioactive wound dressing based on the sample has higher wound closure compared to KE after 21 days. Histopathology of wounds dressed by PCL/CA/KE nanofibers indicated epidermal formation along with a fully extended layer. Eventually, the obtained results confirmed that the PCL/CA/KE nanofibrous sample was a promising wound dressing for burn wound healing.

The electron transfer of redox-active sites of immobilised haemoglobin (Hb) has been studied by voltammetric experiments. The electrode surface was modified by nanoparticles (NPs) to make a suitable substrate for electric wiring of protein molecules and efficient electron transferring. Hence, the Hb/zinc oxide NPs/platinum electrode was prepared by chronoamperometric deposition of the NPs and immobilisation of protein molecules. The electrochemical behaviour of the prepared biosensor was quasi-reversible and showed a pair of redox peaks with a formal potential (E 0′) of 214 mV. Additionally, the electron transfer rate constant (ks ) of immobilised Hb was about 0.621 s−1. Biocatalytic reduction of hydrogen peroxide was also examined on the prepared biosensor. Result indicated to good sensitivity, wide linear range and low detection limit of 6 μM.

In the recent decade, there has been a growing interest in using electrospun polymeric scaffolds for sustained release of drugs. In this work, fibrous scaffolds of polylactic acid/polyethylene glycol (PLA/PEG) were prepared and characterized through scanning electron microscopy, for subsequent utilization as the drug delivery system for cefixime (CF). In this regard, the response surface experimental design (RSM) was successfully used for finding optimized electrospinning condition such as total solution concentration (C_tot), PEG content (%PEG), and applied voltage (V) on the morphology of electrospun PLA/PEG fibrous mats. While increasing the applied voltage and reducing both solution concentration and %PEG resulted in thinner fibers, C_tot was the influential factor on the fiber defects and continuity. Finally, PLA/PEG/CF fine fibers were produced under optimized electrospinning conditions and the controlled drug release profile was obtained in the presence of graphene oxide (GO). GO-CF intermolecular interactions, revealed by attenuated total reflection–Fourier transform infrared spectroscopy (ATR-FTIR) analysis, authorized the drug release mechanism and resulted in near-Fickian diffusion of cefixime from the PLA/PEG/CF/GO fibrous mats.

A sensitive electrochemical sensor is formed by a carbon nanoparticles (CNPs)/glassy carbon electrode for the determination of antidepressant drug fluoxetine in pharmaceutical formulation. The dependence of fluoxetine electro-oxidation currents and potentials on pH concentration and the potential scan rate was studied. Scanning electron microscopy was used for characterisation of the CNPs. The porous layer of the CNPs improved the electroactive surface area and led to a significant increasing in the peak currents, based on the diffusion within a nanoporous film. The best electrochemical response was obtained from differential pulse voltammograms in the buffer solution (pH 9.0). Linear calibration graphs were obtained in 1–25 µM with %RSD values from 0.3 to 5.7 and the detection limit of 0.4 µM (S/N = 3). The CNPs modified electrode was successfully applied for fluoxetine determination in capsules and the results showed sufficient precision and achieved a mean recovery accuracy of 99.06%.

Amlodipine besylate and atorvastatin calcium have been determined by the simultaneous voltammetric method at a multi-walled carbon nanotubes:graphite (MWCNTs:G) paste electrode. In comparison with a glassy carbon electrode, the prepared electrode showed an increase in the peak current because of the high electroactive surface area and excellent electronic conductivity of MWCNTs. The dependence of currents and potentials on pH were investigated for these components at the surface of the MWCNTs:G paste electrode. Differential pulse voltammetry was applied as a sensitive technique for simultaneous determination of the drugs in commercial tablets. By anodic differential pulse voltammetry, the calibration plot was linear in the range of 2.5-100 μg/ml with standard deviation between 2.7-7.1 and 1.8-8.3% for amlodipine and atorvastatin, respectively. The detection limit was 1 μg/ml at the prepared electrode in the buffered solution pH 6.

Direct electrochemical response of cytochrome c (cyt c) on the modified electrode was studied by cyclic voltammetry. The results indicated that cyt c could be adsorbed on the surface of the electrodeposited cobalt oxyhydroxide nanoparticles (CoOx NPs) modified electrode. A couple of well-defined redox peaks can be observed in a phosphate buffer solution (pH 7.0), whose formal potential, E°′ (defined as the average of reductive and oxidative peaks), was −86.5 mV with respect to the reference electrode equal to 110.5 mV against normal hydrogen electrode. Cyt c adsorbed on the surface of CoOx NPs shows a remarkable electrocatalytic activity for the reduction of oxygen. Based on these, a third-generation biosensor could be developed to detect the concentration of oxygen in aqueous solution.

We describe a modification of glassy carbon (GC) electrode surface with electrodeposited cobalt oxide nanoparticles (CoOx NPs), and then, this electrode is used to immobilization of Cytochrome c (Cyt c). The morphology of electrodeposited CoOx NPs was analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Electrochemical redox property investigation of immobilized protein (Cyt c) molecules was accomplished by cyclic voltammetry (CV) technique. Cyt c/CoOx NPs/GC electrode exhibits electron transfer between the protein prosthetic groups and electrodeposited nanoparticles on the electrode surface and displayed a couple of stable redox peaks with a formal potential (E°′) of −89.5 mV (107.5 mV vs. NHE) with respect to reference electrode in 0.05 M phosphate buffer solution (pH 7.0). The experimental results demonstrated that Cyt c/CoOx NPs/GC biosensor exhibited electrocatalytic activity toward the reduction of hydrogen peroxide and application to hydrogen peroxide determination was exemplified.

An electrochemical method for determining the dihydroxybenzene derivatives on glassy carbon (GC) has been developed. In this method, the performance of a single-walled carbon nanotube (SWCNT)/graphite-based electrode, prepared by mixing SWCNTs and graphite powder, was described. The resulting electrode shows an excellent behavior for redox of 3,4-dihydroxybenzoic acid (DBA). SWCNT/graphite-based electrode presents a significant decrease in the overvoltage for DBA oxidation as well as a dramatic improvement in the reversibility of DBA redox behavior in comparison with graphite-based and glassy carbon (GC) electrodes. In addition, scanning electron microscopy (SEM) and atomic force microscopy (AFM) procedures performed for used SWCNTs.

The electrode potential of 2-(4,5-dihydroxy-2-methylphenyl)-2-phenyl-2H-indene-1,3-dione (DMPID) in acetonitrile has been calculated. The calculations were performed using ab initio molecular orbital calculations (HF), and density functional theory (DFT) with the inclusion of entropic and thermochemical corrections to yield free energies of redox reactions. The electrode potential of DMPID was also obtained experimentally with the aid of an electrochemical technique (cyclic voltammetry). The values for geometric parameters and the vibrational frequencies of DMPID and 2-(6-methyl-3,4-dioxocyclohexa-1,5-dienyl)-2-phenyl-2H-indene-1,3-dione (MDPID) were also computed using the same levels with the basis set of 6-31G(d). The calculated IR spectrum of DMPID used for the assignment of IR frequencies was observed in the experimental FT-IR spectrum and the calculated IR and FT-IR observed spectra of DMPID were compared with correlation factor of 0.996. It should be mentioned that the present work is the first research on coagulant derivative molecules in which the electrode potential of a molecule is calculated. Optimized structures of 2-(6-methyl-3,4-dioxocyclohexa-1,5-dienyl)-2-phenyl-2H-indene-1,3-dione (MDPID).

Electron transfer of a redox protein at a bare gold electrode is too slow to observe the redox peaks. A novel Nafion-riboflavin functional membrane was constructed during this study and electron transfer of cytochrome c, superoxide dismutase, and hemoglobin were carried out on the functional membrane-modified gold electrode with good stability and repeatability. The immobilized protein-modified electrodes showed quasi-reversible electrochemical redox behaviors with formal potentials of 0.150,0.175, and 0.202 V versus Ag/AgCl for the cytochrome c, superoxide dismutase and hemoglobin, respectively. Whole experiment was carried out in the 50 mM MOPS buffer solution with pH 6.0 at 25 °C. For the immobilized protein, the cathodic transfer coefficients were 0.67, 0.68 and 0.67 and electron transfer-rate constants were evaluated to be 2.25, 2.23 and 2.5 s -1 , respectively. Hydrogen peroxide concentration was measured by the peroxidase activity of hemoglobin and our experiment revealed that the enzyme was fully functional while immobilized on the Nafion-riboflavin membrane.

Silver nanoparticles have an activity for high intensity electron transfer. They can facilitate the electron transfer from the redox centre of a protein, as a high volume molecule, to the electrode surface. In this study, silver nanoparticles were deposited on the surface of a graphite carbon electrode in the 1 V potential region. Deposition of silver nanoparticles, with a diameter between 70 and 150 nm, was observed on the graphite electrode by transmission electron microscopy (TEM). The results demonstrated that the fine redox waves of haemoglobin could be achieved after modification of the graphite electrode by silver nanoparticles. The cathodic and anodic peaks of haemoglobin were at −135 and +375 mV vs. Ag/AgCl, respectively. The effect of guanosine 3′,5′-triphosphate (GTP), guanosine diphosphate (GDP) and guanosine monophosphate (GMP) on the structure of haemoglobin was investigated. It was observed that GTP shifts the cathodic and anodic peaks positively, indicating the transfer of the haem group to the surface of protein as a reflex of easier oxidation and reduction, while GDP and GMP do not show this behaviour. GTP binds with haemoglobin, while GDP and GMP do not.

Metal substation as an efficient approach for improvement of battery performance of LiMn2O4 was performed by an actinide dopant. Uranium as the last natural element and most common actinide was employed for this purpose. Cyclic voltammetric studies revealed that incorporation of uranium into LiMn2O4 spinel significantly improves electrochemical performance. It also strengthens the spinel stability to exhibit better cycleability. Surprisingly, the capacity increases upon cycling of LiU0.01Mn1.99O4 cathode. This inverse behavior is attributed to uniform distribution of dopant during insertion/extraction process. In other words, this is an electrochemical refinement of the nanostructure which is not detectable in microscale morphology, as rearrangement of dopant in nanoscale occurs and this is an unexceptional nanostructural ordering. In addition, uranium doping strengthens the Li diffusion, particularly at redox potentials. © 2005 Elsevier B.V. All rights reserved.

Plants have been used as medicines for thousands of years. They have been applied for the preparation of ingredients and drugs in the treatment of diseases [1-4]. Clinical studies revealed that a diet rich in fruits and vegetables decreased risk of cardiovascular diseases and cancers. These beneficial health effects have emanated from the presence of antioxidant compounds in the plants. Oxidation is one of the most important chemical and biochemical processes. Free radicals can oxidize nucleic acids, proteins and lipids, initiating degenerative diseases. Antioxidants such as phenolic compounds are compounds known to react with free oxygen radicals and thus preventing their cell-damaging action. Therefore, screening for antioxidant properties of plant extracts is prominent in their pharmaceutical applications. Different methods have been reported for the evaluation of antioxidant capacity of medicinal plant extracts. In the present research cyclic voltammetry have been used for antioxidant screening of medicinal plant extracts. Since, electrochemical techniques are low-cost and enable rapid analysis of sample. Cyclic voltammetry on carbon nanotube modified electrode appears to be a suitable tool in antioxidant assays. It can provide information about the number of compounds redox states and the stability of these states [5]. In this work, leaves of matricaria ineora, as a medicinal plant, were dried at shadow and at room temperature. The 3.0 g powdered leaves of the plant were macerated with 50 mL of ethanol:water (20:80) for 24 h and sonicated for 12 min. The extracts were filtered using filter paper. The voltammograms were obtained for electrochemical oxidation of antioxidant compounds on the bare and modified electrodes in two separate experiments in buffer solution (pH 7.2). It have been compared the cyclic voltammograms of matricaria ineora extract at a bare and single-walled carbon nanotube (SWCNT) modified glassy carbon electrodes. The cyclic voltammetric responses for electrochemical oxidation of extract on the bare electrode containing one pair redox peak and modified electrode containing two pair redox peaks at 100 mV/s. The peak current increased significantly on the SWNTs modified electrode as compared with the bare electrode. The electrode surface modification with SWCNTs augmented its effective surface area and the oxidation currents of antioxidants. The first redox peaks are related to compounds which also were oxidized on the bare glassy carbon electrode. Second peaks are related to compounds which cannot oxidize on the bare electrode but due to nanotubes electrocatalysis property oxidized them on the modified electrode. References: H. Benmehdi, O. Hasnaoui, O. Benali, F. Salhi, J. Mater. Environ. Sci. 3 (2012) 320-237. O. Maschi, E. Dal Cero, G.V. Galli, D. Caruso, E. Bosisio, M. Agli, J. Agric. Food Chem. 56 (2008) 5015-5020. A. Ghorbani, B. Gravendeel, S. Selliah, S. Zarreo, H. de Boer, Mol. Ecol. Resour. (2016) doi:10.1111/1755-0998.12615 L. Barros, L. Cabrita, M.V. Boas, A.M. Carvalho, I. Ferreira, Food Chem. 127 (2011) 1600-1608. L. Campanella, E. Martini, M. Tomassetti, Talanta 66 (2005) 902-911.

Clinical and Epidemiological studies have shown that a diet rich in fruits and vegetables is associated with a decreased risk of cardiovascular diseases, cancers and other related disorders. These beneficial health effects have been attributed in part to the presence of antioxidants in dietary plants. Therefore screening for antioxidant properties of plant extracts has been one of the interests of scientists in this field. Different screening methods have been reported for the evaluation of antioxidant properties of plant extracts in the literature. In the present research a rapid screening method has been introduced based on cyclic voltammetry for antioxidant screening of some selected medicinal plant extracts. Cyclic Voltammetry of methanolic extracts of seven medicinal plants: Buxus hyrcana, Rumex crispus, Achillea millefolium, Zataria multiflora, Ginkgo biloba, Lippia citriodora and Heptaptera anisoptera was carried out at different scan rates. Based on the interpretation of voltammograms, Rumex crispus, Achillea millefolium and Ginkgo biloba showed higher antioxidant capability than the others while Lippia citriodora contained the highest amount of antioxidants. Cyclic voltammetry is expected to be a simple method for screening antioxidants and estimating the antioxidant activity of foods and medicinal plants.

In this study, a simple method was developed and validated to detect trace levels of benzaldehyde in injectable pharmaceutical formulations by solid-phase microextraction coupled with gas chromatography– flame ionization detector. Polyaniline was electrodeposited on a platinum wire in trifluoroacetic acid solvent by cyclic voltammetry technique. This fiber shows high thermal and mechanical stability and high performance in extraction of benzaldehyde. Extraction and desorption time and temperature, salt effect and gas chromatography parameters were optimized as key parameters. At the optimum conditions, the fiber shows good linearity between peak area ratio of benzaldehyde/3-chlorobenzaldehyde and benzaldehyde concentration in the range of 50–800 ng/mL with percent relative standard deviation values ranging from 0.75 to 8.64% (n 5 3). The limits of quantitation and detection were 50 and 16 ng/mL, respectively. The method has the requisite selectivity, sensitivity, accuracy and precision to assay benzaldehyde in injectable pharmaceutical dosage forms.

A novel nafion-riboflavin membrane was constructed and characterized by the scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-visible spectroscopy and cyclic voltammetric techniques. The estimated average diameter of the designed nanoparticles was about 60 nm. The functional membrane showed a quasi-reversible electrochemical behaviour with a formal potential of -562 +/- 5 mV (vs Ag/AgCl) on the gold electrode. Some electrochemical parameters were estimated, indicating that the system has good and stable electron transfer properties. Moreover, horseradish peroxidase (HRP) was immobilized on the riboflavin-nafion functional membrane. The electrochemical behaviour of HRP was quasi-reversible with a formal potential of 80 +/- 5 mV (vs Ag/AgCl). The HRP in the film exhibited good catalytic activity towards the reduction of H2O2. It shows a linear dependence of its cathodic peak current on the concentration of H2O2, ranging from 10 to 300 (micro)M.

Novel fluorescent molecules were synthesized by designing an environmentally friendly method involving the bulk electrolysis technique. This electrochemical treatment process helps protect the environment by minimizing the toxic waste component of effluent. The electrochemical oxidation of 3,6-dihydroxybenzene-1,2-dinitrile (DBD) in the presence of benzenesulfinic acids was studied in an aqueous solution (H(2)O : AN, 90 : 10), which included an acetate buffer (pH=5.0). This research utilized a variety of experimental techniques, including cyclic voltammetry, controlled-potential electrolysis as well as spectroscopic identification of compounds produced as products. In addition, our fluorescent studies offered results in line with existing findings. At the wavelength of 205 nm, DBD and compound (6) were excited and their fluorescent emissions were monitored.

This is an environmentally friendly method in the field of electroorganic reactions under controlled potential electrolysis, without toxic reagents at a carbon electrode in an undivided cell which involves the (EC) mechanism reaction and comprises two steps alternatively; (i) electrochemical oxidation and (ii) chemical reaction. In particular, the electrochemical oxidation of 4-tert-butylcatechol, 4-methylcatechol and 2,3-dihydroxybenzoic acid in the presence of 2-phenyl-1,3-indandione has been studied in a water-acetonitrile (90 : 10) mixture. The research includes the use of a variety of experimental techniques, such as cyclic voltammetry, controlled-potential electrolysis, and spectroscopic identification of products (FT-IR, (1)H-NMR, and MS spectrometry).

Reactive oxygen species (ROS), including hydrogen peroxide, hydroxyl radical, superoxide anion, and peroxynitrite are involved in some diseases. Among the ROS, H2O2 is the most durable species which is a product of several biological, enzyme-catalyzed reactions. In addition, it is toxic to cellular life and is an indicator of oxidative stress. Therefore, a selective and sensitive method for determination of H2O2is practically important, especially in the field of biosensor fabrication. Biosensors have attracted attention for use in biodiagnostics [1]. The capability of biosensors will be completely changed by advances in nanoscience and nanotechnology. Nanostructured metals and metal oxides have various applications in sensors and actuators due to their unique semiconducting and piezoelectric properties [2]. Good biocompatibility, nontoxicity, high surface area, and in particular, chemical stability and fast electron transfer features make them appropriate to apply in various fields. In this work, cerium oxide nanoparticles (CeO2 NPs) on the electrode surface were electrodeposited. Cerium was firstly electrodeposited at -0.75 V from a 1.0 mM cerium nitrate in ammonium nitrate buffer solution. Afterwards, the electrode was placed into a buffer solution pH 7.0 and was electrochemically passivated. Scanning electron microscopy has been used as diagnostic tools to identify the synthesized CeO2 NPs. For the preparation of biosensor, the hemoglobin immobilized on the CeO2NPs. Immobilized Hb showed an electrochemical redox behavior pertained to Hb(Fe(III)-Fe(II)) by direct electron transfer between protein and nanoparticles with a formal potential of -55.5 mV in phosphate buffer solution (PBS). The anodic charge transfer coefficient (α) and heterogeneous electron transfer rate constant (k s) were 0.42 and 0.75 s-1, respectively. The prepared biosensor showed a satisfactory sensitivity and reproducibility for H2O2. References: 1. Y. Ding, J. Li, R.E. Campbell, Nature Methods, 12, 195 (2015). 2. R.C. Ashoori, Nature, 379, 413 (1996).

In this study, Y2O3:Eu nanocrystals (NCs) were prepared through the combustion, Pechini and hydrothermal methods followed by the heat treatment of samples at 873 K. The resultant NCs were investigated by X-ray diffractometery, scanning electron microscopy, transmission electron microscopy, selected area electron diffractometery and photoluminescence (PL) spectroscopy. The obtained sample by the Pechini method presents cubic phase, whereas the hydrothermal sample consists of different phases (cubic, monoclinic and hexagonal phases of Y2O3 besides yttrium nitrate hydrate phase). Cubic and monoclinic phases of Y2O3 as well as tetragonal phase of yttrium oxide nitride (YO(NO3)3) phases were observed in combustion sample before heat treatment, whereas just the cubic phase stayed after heat treatment of this sample. The morphological investigations demonstrated that the hydrothermal sample has flower-like morphology with micron-size petals, whereas other samples have rounded particles. The PL intensity and chromaticity of Pechini sample are not as good as combustion and hydrothermal samples, but low agglomeration of the Pechini sample makes it good candidate for biological applications as a luminescence sensors and tags.

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To study the relation between conductance, photoluminescence bands and structure of indium tin oxide (ITO), nano- and microparticles of ITO were synthesised using various methods, including hydrothermal, oxalate precursor decomposition and Pechini type sol–gel combustion methods. The resultant powders were analysed by X-ray diffraction (XRD), resistance measurement, photoluminescence (PL) spectroscopy and scanning electron microscopy techniques. The crystallographic and microstructural parameters of samples were refined from the XRD patterns utilising Rietveld method. Two PL bands were observed in 475 and 560 nm and it was found that the low-energy PL band intensity presents direct relation with conductivity of samples while the other one shows inverse relation. Pechini samples demonstrated the highest conductivity and low-energy PL band intensity, while hydrothermal sample has low conductivity. It was suggested that the low-energy PL band is the characteristics of excitons trapped in oxygen vacancy while the high-energy PL band is attributed to the excitons trapped in other defects centre. The colour of samples and data resulted from XRD pattern refinement were also validated. According to the refinement results and Popa's model, all samples show anisotropic micro-strain and crystallite size. It was also deduced that hydrothermal sample was textured in the 〈111〉 direction.

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In this work, CoFe2O4 nanoparticles have been prepared by co-precipitation technique. The synthesized CoFe2O4 nanoparticles were applied in the preparation of CoFe2O4/Polyacrylonitrile fiber nanocomposites by the electrospinning process. The prepared nanoparticles and nanofibers were characterized using the Scanning Electron Microscopy (SEM) and X-ray diffraction methods. The results manifested that nanofibers of PAN and CoFe2O4 /PAN were successfully prepared with electrospinning method. Grayscale SEM images of nanofibers were analyzed by a new image analysis procedure for determination of fibers diameter, their diameter distribution and the compactness of electrospun nanofibers. It was found that the presence of CoFe2O4 nanoparticles in the PAN solution increases both of the compactness of electrospun nanofibers and their diameter. The prepared CoFe2O4/Polyacrylonitrile fiber nanocomposites have possible applications in fabrication of sensor and magnetic recording media.