FeCl3 Concentration Research Articles

Iron-induced oxidative stress activates AKT and ERK1/2 and decreases Dyrk1B and PRMT1 in neuroblastoma SH-SY5Y cells

Iron is essential for proper neuronal functioning; however, excessive accumulation of brain iron is reported in Parkinson’s, Alzheimer’s, Huntington’s diseases and amyotrophic lateral sclerosis. This indicates that dysregulated iron homeostasis is involved in the pathogenesis of these diseases. To determinate the effect of iron on oxidative stress and on cell survival pathways, such as AKT, ERK1/2 and DyrK1B, neuroblastoma SH-SY5Y cells were exposed to different concentration of FeCl2 (iron). We found that iron induced cell death in SH-SY5Y cells in a concentration-dependent manner. Detection of iNOS and 3-nitrotyrosine confirms the presence of increased nitrogen species. Furthermore, we found a decrease of catalase and protein arginine methyl-transferase 1 (PRMT1). Interestingly, iron increased the activity of ERK and AKT and reduced DyrK1B. Moreover, after FeCl2 treatment, the transcription factors c-Jun and pSmad1/5 were activated. These results indicate that the presence of high levels of iron increase the vulnerability of neurons to oxidative stress.

Synthesis of dispersive iron or iron–silver nanoparticles on engineered capsid pVIII of M13 virus with electronegative terminal peptides

M13 is a filamentous Escherichia coli virus covered with five types of capsid proteins, in which pVIII with ~2700 copies was around the cylindered surface and pIII with five copies located at one end of the phage particle. The pIII-engineered M13 phages with enhanced binding specificity toward Fe were screened after five rounds of biopanning, and the one containing ATPTVAMSLSPL peptide at pIII-terminus was selected for mediated synthesis of zero valent (ZV) Fe nanoparticles (NPs) with the wild M13 as control. Under a reducing environment, uniformly dispersed ZVFeNPs with diameter of 5–10 nm were both synthesized and the morphologies after annealing were confirmed to be face-centered cubic type. The synthesized FeNPs mediated by the two phages showed no significant difference, revealing that the pVIII capsid did dominant contribution to metal binding in comparison with the pIII. A novel pVIII-engineered M13 containing AAEEEDPAK at terminus, named as 4ED-pVIII-M13, was constructed and it carried one more negatively charged residue than the wild one (AEGDDPAK). Metal adsorption quantification showed that the binding affinity of the 4ED-pVIII-M13 toward Ag and Ni ions improved to 62 and 18 % from original 21 and 6 %, respectively. The binding affinity toward Fe remained constant (~85 %). ZVFe–Ag bi-NPs were successfully synthesized through mediation of 4ED-pVIII-M13. Particularly, the Fe:Ag ratio in the bi-NPs was conveniently controlled through changing the molar concentration of FeCl2 and AgNO3 solution before reduction.

Resolving the multifaceted mechanisms of the ferric chloride thrombosis model using an interdisciplinary microfluidic approach

AbstractThe mechanism of action of the widely used in vivo ferric chloride (FeCl3) thrombosis model remains poorly understood; although endothelial cell denudation is historically cited, a recent study refutes this and implicates a role for erythrocytes. Given the complexity of the in vivo environment, an in vitro reductionist approach is required to systematically isolate and analyze the biochemical, mass transfer, and biological phenomena that govern the system. To this end, we designed an “endothelial-ized” microfluidic device to introduce controlled FeCl3 concentrations to the molecular and cellular components of blood and vasculature. FeCl3 induces aggregation of all plasma proteins and blood cells, independent of endothelial cells, by colloidal chemistry principles: initial aggregation is due to binding of negatively charged blood components to positively charged iron, independent of biological receptor/ligand interactions. Full occlusion of the microchannel proceeds by conventional pathways, and can be attenuated by antithrombotic agents and loss-of-function proteins (as in IL4-R/Iba mice). As elevated FeCl3 concentrations overcome protective effects, the overlap between charge-based aggregation and clotting is a function of mass transfer. Our physiologically relevant in vitro system allows us to discern the multifaceted mechanism of FeCl3-induced thrombosis, thereby reconciling literature findings and cautioning researchers in using the FeCl3 model.

Diffusion-Limited 1D Pit Growth of S13Cr in Brine at Elevated Temperature

Diffusion-limited pit growth of Super 13Cr stainless steel (S13Cr) was studied using one-dimensional (1D) pit electrodes in 0.1 – 3 M NaCl solutions at 85 °C. Applied potential (Eapp) was controlled in four different steps to achieve a target pit depth and measure the anodic current density for S13Cr dissolution under potentiostatic polarization and during a backward scan. For pits with similar depths, the diffusion-limited current density (ilim) of anodic dissolution decreased with increasing NaCl concentration. A characteristic potential, below which the current density started to decay from steady ilim, was found during the backward scan. This potential is associated with dissolution of a salt film at the pit bottom and was defined as the potential of salt film dissolution (Esfd). Esfdalso decreased with increasing NaCl concentration. To explain the dependence of ilim and Esfd on NaCl concentration, the diffusion coefficient of metal ions (D) and saturation concentration of FeCl2 (Csat), which are directly associated with the product of pit depth and ilim, were calculated using model concentration profiles in a pit and a thermodynamic database software. Both D and Csat were predicted to decrease as NaCl concentration increased, indicating slower diffusion and easier precipitation of salt film, which both increase the stability of a salt film. The product of the calculated D and Csat values was used to predict ilim for certain pit depths, and the predicted ilim values were in the range of experimentally-measured ilim in different NaCl concentrations, which validated the model.

Synthesis and electrical properties of silver nanoplates for electronic applications

Abstract In this paper, silver nanoplates of 100 to 500 nm size were synthesized by reduction of silver nitrate with N,Ndimethylformamide, using poly(vinylpyrolidone) as a surfactant and ferric chloride as a controlling agent, at 120 to 160 °C for 5 to 24 hours. The influence of the concentration of ferric chloride, the reaction temperature and reaction time on the morphology of the product has been investigated by transmission electron microscopy, scanning electron microscopy and UV-Vis spectroscopy. The results indicated that the products obtained at the low reaction temperature and short reaction time in the presence of FeCl3 in the reaction solution were in the form of silver nanoplates, whose morphology was mainly triangular and hexagonal. In addition, the size and thickness of the nanoplates increased with increasing of the FeCl3 concentration. At a high reaction temperature and long reaction time, the truncated triangle and hexagonal nanoplates were mainly produced. Furthermore, the sintering behavior of nanoplates was studied and the results showed that sintering of the silver nanoplates started at 180 °C, and a typical sintering behavior was observed at higher temperatures. The incorporation of the silver nanoplates into the polymer matrix with micro-sized silver flakes led to an increase in the matrix resistivity in almost all cases, especially at high fractions and low curing temperatures. The curing temperature had an influence on the resistivity of the conductive adhesives filled with micro-sized silver flakes and silver nanoplates due to sintering of the silver nanoplates.

Coagulation/flocculation optimization and sludge production for pre-treatment of paint industry wastewater

AbstractThis study examined the optimization of paint industry wastewater pre-treatment by means of coagulation and the quantity of produced sludge generated. In preliminary tests, high concentrations of alum, PACI, and FeCl3 were used, and removal efficiencies were determined to be 86–88%, 100%, and 46–72% for chemical oxygen demand (COD), SS, and color, respectively. Actual studies were conducted by adding lower concentrations of coagulants to reduce the produced sludge quantity due to the addition of coagulants at high concentrations. In those studies, COD removal efficiency decreased by 10%, while suspended solids and color removal increased. The optimum removal efficiency was obtained by adding 250 mg/L alum and FeCl3, and the optimum anionic polyelectrolyte dose was found to be 4 mg/L. When equal amounts of coagulants were dosed, the quantities of sludge were found to be FeCl3 > PACl > FeSO4 ≥ alum. Considering the treatment efficiency and quantity of sludge together, the most economical solution wi...

The Effect of FeCl3 in the Shape Control Polyol Synthesis of Silver Nanospheres and Nanowires

Morphologically controlled nanostructures have been increasingly important because of their strongly shape dependent physical and chemical properties. This study discusses the effect of FeCl3 concentration over synthesis of silver nanospheres and nanowires (NWs) by reducing silver nitrate (AgNO3) with ethylene glycol through a simple polyol method and using poly(vinylpyrrolidone) as capping agent. X-ray diffraction (XRD), ultraviolet visible spectroscopy, scanning electron microscopy and transmission electron microscopy were performed in order to find the structural and geometrical features of silver nanostructures. XRD analysis confirmed formation of metallic silver phase and microscopic studies revealed formation of NWs with average diameters ranging from 50 to 100 nm. Different concentrations of ferric chloride (FeCl3) are used to control the morphology and shape changes of primary silver seeds. A mixture of silver nanospheres and NWs are formed at 0.05 mM concentration of FeCl3 while increasing the concentration of FeCl3 to 0.1 mM lead to formation of silver NWs. Moreover, an increase in the concentration of FeCl3 from 0.1 to 0.3 mM results in reduction of aspect ratio of silver NWs. Furthermore, more increase in FeCl3 concentration from 0.3 mM results again in formation of semi spherical shapes silver nanostructures.

Simple synthesis of conducting poly(2-aminothiazole) with high molecular weight

Chemical and electrochemical oxidative polymerizations are the most used methods to synthesize conducting polymers such as polyaniline, polypyrrole, and polythiophene. However, a significant generic problem for these methods is that a high amount of oxidants or electrolytes are needed, which are usually difficult to be removed. Here we report a simple synthesis of conducting poly(2-aminothiazole) (P2AT) in nitromethane (CH3NO2) using ferric chloride (FeCl3) as an oxidant at a low amount (could be as low as 1 mol%, related to 2-aminothiazole). The effects of reaction temperature, reaction time, and FeCl3 concentration on the yield of polymerization were systematically investigated. The P2ATs were fully characterized by FT-IR, 1H NMR, UV-vis, gel permeation chromatograms (GPC), and thermogravimetric analysis (TGA). Optimization of the synthetic conditions allows P2AT with both high yield (53 %) and thermal stability (62 % of residue at 600 °C) to be achieved simultaneously. Possible polymerization mechanism was also proposed. Four-probe conductivity measurement indicated that the P2AT exhibited good semi-conductive property with tunable values of 10−5–10−3 S/cm upon iodine (I2) doping. Simple synthesis of P2AT using a low amount of FeCl3 would be a very promising protocol to expand conducting polymer family.

Evaluation of ionic liquids as alternative solvents for aldolase activity: Use of a new automated SIA methodology

An automated methodology is proposed for the evaluation of a set of ionic liquids (ILs) as alternative reaction media for aldolase based synthetic processes. For that, the effect of traditionally used organic solvents and ILs on the activity of aldolase was studied by means of a novel automated methodology.The implemented methodology is based on the concept of sequential injection analysis (SIA) and relies on the aldolase based cleavage of d-fructose-1,6 diphosphate (DFDP), to produce dihydroxyacetone phosphate (DHAP) and d-glyceraldehyde-3-phosphate (G3P). In the presence of FeCl3, 3-methyl-2-benzothiazoline hydrazine (MBTH) forms a blue cation that can be measured at 670nm, by combination with G3P. The influence of several parameters such as substrate and enzyme concentration, temperature, delay time and MBTH and FeCl3 concentration were studied and the optimum reaction conditions were subsequently selected. The developed methodology showed good precision and a relative standard deviation (rsd) that does not exceed 7% also leading to low reagents consumption as well as effluent production.Resorting to this strategy, the activity of the enzyme was studied in strictly aqueous media and in the presence of dimethylformamide, methanol, bmpyr [Cl], hmim [Cl], bmim [BF4], emim [BF4], emim [Ac], bmim [Cl], emim [TfMs], emim [Ms] and Chol [Ac] up to 50%.The results show that the utilization of ILs as reaction media for aldolase based organic synthesis might present potential advantages over the tested conventional organic solvents. The least toxic IL found in this study was cho [Ac] that causes a reduction of enzyme activity of only 2.7% when used in a concentration of 50%. Generally, it can be concluded that ILs based on choline or short alkyl imidazolium moieties associated with biocompatible anions are the most promising ILs regarding the future inclusion of these solvents in synthetic protocols catalyzed by aldolase.

Drying of Iron Chloride Solutions: Laser Heating of Levitated Single Particles

AbstractIron chloride solutions are a waste product from the steel industry, which has to be recovered by the so‐called spray roasting process. As this process is a complex sequence of different steps, the drying process of the droplets was separated to get deeper insight into the particle formation process from aqueous iron chloride solutions. Experiments were carried out on single droplets in an acoustic levitator. A CO2 laser was used as heat source for the drying process. Particles with different shapes were generated by various concentrations of FeCl2 and laser power. The characteristic time scales and particle size evolution are compared with literature data.

Conductive polypyrrole/viscose fiber composites

Polypyrrole (PPy) was polymerized with pyrrole (Py) as the monomer, FeCl3 as an oxidant and sodium dodecyl benzene sulfonate (SDBS) as the dopant on the surface of viscose fiber (VCF) to prepare the conductive PPy/VCF composites. Fourier transform infrared spectra (FT-IR), thermal gravimetric analysis (TGA) and X-ray photoelectron spectroscope (XPS) proved that the interaction between PPy and VCF formed in the PPy/VCF composites. Three structures of N atoms (imine, amine and cationic atoms) were found in PPy of PPy/VCF composites. The influence of reaction conditions including reaction time, Py concentration, FeCl3 concentration and SDBS concentration on the morphology and the conductivity of PPy/VCF composites was investigated in detail. The orthogonal experiments were designed to determine the optimal reaction conditions: reaction time 5h, Py concentration 0.1mol/L and FeCl3 concentration 0.25mol/L. When PPy/VCF composite was washed 50 times in water, the conductivity still kept at 1.5S/cm, and this value was stable for more washing.

Size-Controllable Synthesis of Fe3O4 Nanospheres for Electromagnetic Wave Absorber

We present a hydrothermal method to control the size of Fe3O4 nanospheres by adjusting the concentration of FeCl3·6H2O in ethylene glycol/diethylene glycol binary solvent mixtures. The electromagnetic wave absorption properties of Fe3O4 nanospheres of different diameters have been investigated using a vector network analyzer. The reflection loss of Fe3O4 nanospheres/paraffin wax composite can reach as high as −30.00 dB at 17.50 GHz and −37.95 dB at 7.67 GHz for Fe3O4 nanospheres with diameter of about 120 nm and 170 nm, respectively. The absorption bandwidth with reflection loss below −10 dB is up to 7.01 GHz when the Fe3O4 diameter is about 220 nm. In contrast, the bandwidth decreased to 4.28 GHz when the size shrank to 70 nm. Therefore, our method can be utilized to precisely control the size of Fe3O4 nanospheres in order to manipulate their electromagnetic wave absorption properties.

Dose- and Time-Dependent In Vitro Effects of Divalent and Trivalent Iron on the Activity of Bovine Spermatozoa.

This in vitro study was designed to assess the impact of divalent (Fe(2+)) or trivalent (Fe(3+)) iron on the activity and oxidative balance of bovine spermatozoa at specific time intervals (0, 2, 8, 16, and 24h) during an in vitro culture. Forty-five semen samples were collected from adult breeding bulls and diluted in physiological saline solution supplemented with different concentrations (0, 1, 5, 10, 50, 100, 200, 500, 1000μmol/L) of FeCl2 or FeCl3. Spermatozoa motion parameters were assessed using the SpermVision™ computer-aided sperm analysis (CASA) system. Cell viability was examined with the metabolic activity 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and the nitroblue-tetrazolium (NBT) test was applied to quantify the intracellular superoxide formation. Both divalent and trivalent iron exhibited a dose- and time-dependent impact on the spermatozoa physiology and oxidative balance. Concentrations ≥50μmol/L FeCl2 and ≥100μmol/L FeCl3 led to a significant decrease of spermatozoa motility (P < 0.05) and mitochondrial activity (P < 0.001 with respect to 200-1000μmol/L FeCl2/FeCl3; P < 0.01 in case of 100μmol/L FeCl2/FeCl3), accompanied by a significant superoxide overproduction (P < 0.001 in terms of 200-1000μmol/L FeCl2 and 500-1000μmol/L FeCl3; P < 0.01 with respect to 100μmol/L FeCl2 and 100-200μmol/L FeCl3). On the other hand, concentrations below 10μmol/L FeCl2 and 50μmol/L FeCl3 proved to stimulate the spermatozoa activity, as shown by a significant preservation of the motility and viability characteristics (P < 0.001 in case of the motility parameters; P < 0.01 with respect to the spermatozoa viability), alongside a significant decline of the superoxide generation (P < 0.05). In a direct comparison, divalent iron has been shown to be more toxic than trivalent iron. Results from this in vitro study show that high concentrations of both forms of iron are toxic, while their low concentrations may have spermatozoa activity-promoting properties. In vitro concentrations of divalent or trivalent iron that could be regarded as critical are 50μmol/L FeCl2 and 100μmol/L FeCl3 when iron ceases to be an essential micronutrient in order to become a toxic risk factor.

Development and Optimization of Biometal Nanoparticles by Using Mathematical Methodology: A Microbial Approach

This study aimed to biosynthesize and optimize the process of iron oxide nanoparticles producing by Penicilliumwaksmanii isolated from soil by employing mathematical methodology. The synthesized nanoparticles were formed with fairly well-defined dimensions with good monodispersity determined by SEM (Scanning Electron Microscopy), AFM (Atomic Force Microscopy), DLS (Dynamic Light Scattering), UV-Visible spectroscopy, zeta potential, polydispersity index (PDI) and correlogram of nanoparticles. The effects of different factors such as pH, temperature and concentration of FeCl3 on the particle size were investigated by Box-Behnken experimental design. The R2 value was calculated to be 0.9992 indicating the accuracy and ability of the polynomial model.

New particle formation above a simulated salt lake in aerosol chamber experiments

Environmental context Deforestation in Western Australia beginning in the mid-19th century led to a considerable change of the land surface, and Western Australia is now suffering more often from droughts. Particle formation induced by salt lakes has been identified as a potential control factor for changed precipitation patterns. This study aims to determine key factors involved in the particle formation process by simulating a simplified salt lake in an aerosol chamber in the laboratory. Abstract In recent field experiments, particle formation has been observed above salt lakes in Western Australia and related to changes in regional precipitation patterns. This work investigates the particle formation potential above a simulated salt lake in aerosol chamber experiments under various conditions. The salt lake mixture comprised fixed concentrations of NaBr, NaCl and Na2SO4, and varying concentrations of FeSO4 and FeCl3. Further, an organic mixture of 1,8-cineol and limonene was added under dark and light conditions. Both the presence of organic compounds and of light were found to be essential for new particle formation in our experiments. There were clear indications for conversion of FeII to FeIII, which suggests a Fenton-like reaction mechanism in the system. Contrary to the idea that a Fenton-like reaction mechanism might intensify the oxidation of organic matter, thus facilitating secondary organic aerosol formation, the observed particle formation started later and with lower intensity under elevated FeII concentrations. The highest particle number concentrations were observed when excluding FeII from the experiments. Chemical analysis of the formed aerosol confirmed the important role of the Fenton-like reaction for particle formation in this study. Ultrahigh-resolution mass spectrometry and Raman spectroscopy provide analytical proof for the formation of organosulfates and halogenated organic compounds in the experiments presented. Even though halogens and organic precursors are abundant in these experimental simulations, halogen-induced organic aerosol formation exists but seems to play a minor overall role in particle formation.

Modulation of crude glycerol fermentation by Clostridium pasteurianum DSM 525 towards the production of butanol

High production yields and productivities are requisites for the development of an industrial butanol production process based on biodiesel-derived crude glycerol. However, impurities present in this substrate and/or the concentration of glycerol itself can affect the microbial metabolism. In this work, the effect of crude glycerol concentration on the production of butanol and 1,3-propanediol (1,3-PDO) by Clostridium pasteurianum DSM 525 is studied. Also, the effect of acetate and butyrate supplementation to the culture medium and the culture medium composition are evaluated. The results showed a marked effect of crude glycerol concentration on the product yield. The competitive nature of butanol and 1,3-PDO pathways has been evident, and a shift to the butanol pathway once using higher substrate concentrations (up to 35 g l−1) was clearly observed. Butyrate supplementation to the culture medium resulted in a 45% higher butanol titre, a lower production of 1,3-PDO and it decreased the fermentation time. Acetate supplementation also increased the butanol titre but the fermentation was longer. Even though glycerol consumption could not be increased over 32 g l−1, when the concentrations of NH4Cl and FeCl2 were simultaneously increased, the results obtained were similar to those observed when butyrate was supplemented to the culture medium; a 35% higher butanol yield at the expense of 1,3-PDO and a shorter fermentation. The results herein gathered suggest that there are other factors besides butanol inhibition and nutrient limitation that affect the glycerol consumption.

Catalytic Extraction of Microcrystalline Cellulose (MCC) from Elaeis guineensis using Central Composite Design (CCD)

Cellulosic fiber extracted from a non-woody, monocotyledonous species of palm tree trunk (PTT) was hydrolyzed with different concentrations of FeCl3 in the presence of hydrochloric acid. The dissolution properties of the amorphous region of palm tree cellulosic fiber (PTC) can be enhanced in the presence of Fe3+ cations in acidic medium. The independent variables, including temperature (x1), time (x2), and concentration of metal chloride (FeCl3) catalyst (x3), were optimized using central composite design (CCD). Responses were measured in terms of percentage crystallinity (y1) and yield (y2) of the prepared hydrocellulose. Analysis of variance (ANOVA) showed that temperature was the most influential factor for hydrolyzing the amorphous sections of cellulose. Under optimum conditions, the percentage crystallinity (y1) and yield (y2) were 68.66% and 83.98%, respectively. Scanning electron microscopy (SEM) analysis and X-ray diffraction techniques were used to obtain more information about the surface morphology and crystallinity of the prepared microcrystalline cellulose (MCC). Infrared spectroscopy and thermal analysis were performed to observe the effect of hydrolysis on the finished products. It was concluded that the addition of FeCl3 salt in acid hydrolyzing medium can substantially increase the crystallinity of palm tree trunk cellulose with significant morphological changes to yield microcrystalline cellulose (MCC).

Analysis of microbial fuel cell operation in acidic conditions using the flocculating agent ferric chloride

AbstractBACKGROUNDFerric chloride (FeCl3) is widely used as a flocculating agent during wastewater treatment but can detrimentally lower pH and increase iron concentration. Microbial fuel cells (MFCs) are a promising technology for treating waste while concomitantly producing electricity and so were tested under the extreme conditions imposed by the addition of FeCl3. MFCs were fed eight concentrations of FeCl3 over two 8‐week periods and the effects on power, pH, conductivity, metal content and COD were examined.RESULTSMFCs generated highest power (3.58 W m‐3) at 1.6 mmol L‐1 FeCl3 (pH 3.46), however cells reversed when fed 2 mmol L‐1 (pH 3.29). During the second run, power almost doubled and MFCs were more resilient at higher loadings up to 2.8 mmol L‐1 (pH 3.02). Conductivity and pH increased following treatment while soluble phosphorus, sulphur and iron levels decreased significantly in all feedstock up to 1.6 mmol L‐1 FeCl3. COD reduction was observed but efficiency may have been affected by the presence of alternative electron donors such as hydrogen sulphide.CONCLUSIONThese findings demonstrate the robustness and versatility of MFCs in hostile conditions. They also confirm that MFCs can complement current wastewater treatment processes, even downstream from FeCl3 dosing where conditions might be deemed unsuitable for operation. © 2014 Society of Chemical Industry

Nisin Incorporated With 2,3-Dihydroxybenzoic Acid in Nanofibers Inhibits Biofilm Formation by a Methicillin-Resistant Strain of Staphylococcus aureus.

The aim of the present study was to determine the effect of nisin, 2,3-dihydroxybenzoic acid (DHBA) and a combination of nisin and DHBA incorporated into nanofibers prepared from poly(D,L-lactide) (PDLLA) and poly(ethylene oxide) (PEO) on biofilm formation of a methicillin-resistant strain of Staphylococcus aureus (strain Xen 31). Biofilm formation decreased by 88% after 24 h of exposure to nanofibers containing nisin and DHBA (NDF), compared to a 63% decrease when exposed to nanofibers containing only DHBA (DF) and a 3% decrease when exposed to nanofibers containing only nisin (NF). Planktonic cell numbers of biofilms exposed to nanofibers without nisin or DHBA (CF) and NF increased from no detectable OD(595nm) readings to 0.35 and 0.3, respectively, within the first 8 h of exposure, followed by a steady decline over the following 16 h. Planktonic cells of biofilms treated with DF increased from no detectable OD(595nm) readings to 0.05 after 8 h of exposure and remained more-or-less constant for the duration of the experiment. Planktonic cells of biofilms exposed to NDF increased from OD(595nm) 0.03 after 8 h of exposure and to 0.2 over the following 16 h. Biofilm formation increased with increasing concentrations of FeCl3·6H2O, which suggests that iron is required for S. aureus Xen 31 to form a biofilm. However, when exposed to NDF, biofilm formation decreased significantly in the presence of increasing concentrations of iron. This suggests that NDF may be used to prevent biofilm formation of MRSA and control infection.

Novel ionically crosslinked acrylamide-grafted poly(vinyl alcohol)/sodium alginate/sodium carboxymethyl cellulose pH-sensitive microspheres for delivery of Alzheimer's drug donepezil hydrochloride: Preparation and optimization of release conditions

In this work, the graft copolymer, poly(vinyl alcohol)-grafted polyacrylamide (PVA-g-PAAm), was synthesized and characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, and elemental analysis. Microspheres of PVA-g-PAAm/sodium alginate (NaAlg)/sodium carboxymethyl cellulose (NaCMC) were prepared by the emulsion-crosslinking method and used for the delivery of an Alzheimer's drug, donepezil hydrochloride (DP). The release of DP increased with the increase in drug/polymer ratio (d/p) and PVA-g-PAAm/NaAlg/NaCMC ratio, while it decreased with the increase in the extent of crosslinking. The optimum DP release was obtained as 92.9% for a PVA-g-PAAm/NaAlg/NaCMC ratio of 1/2/1, d/p ratio of 1/8, and FeCl3 concentration of 7% (w/v).