Iron Chitosan Research Articles

One-step electrochemical deposition of Polypyrrole–Chitosan–Iron oxide nanocomposite films for non-enzymatic glucose biosensor

One-step electrodeposition method of Polypyrrole–Chitosan–Iron oxide (Ppy–CS–Fe3O4) nanocomposite films (Ppy–CS–Fe3O4NP/ITO) has been developed for the fabrication of advanced composite coatings for biosensors applications. The FESEM and EDX results provide the evidence of successful incorporation of Fe3O4 into Ppy–CS molecules. The presence of Fe3O4 nanoparticles in the nanocomposite films was further confirmed by the XRD and XPS spectrums. The fabricated electrode Ppy–CS–Fe3O4 NP/ITO shows a fast amperometric response with high selectivity to detect glucose non-enzymatically with improved linearity (1–16mM) and the detection limit of (234μM) at a signal-to-noise ratio (S/N=3.0).

Pectin beads loaded with chitosan–iron microspheres for specific colonic adsorption of ciprofloxacin

Residual antibiotics reaching the colon can induce severe deleterious effects on the colonic microbiota including the induction of resistance to antibiotics. To avoid the selection of ciprofloxacin resistance, chitosan–iron microspheres were encapsulated into pectin beads with the aim to specifically adsorb residual colonic ciprofloxacin, reducing its time of contact with the endogenous bacteria. In our study, the formulation of beads, their stability as well as their capacity to specifically adsorb ciprofloxacin in simulated digestive media was carried out. Beads incubated in simulated gastric and intestinal media were stable for 1 and 5 h, respectively. When incubated in simulated colonic medium, beads were then degraded by pectinases present in the medium. Coating with Eudragit® RS was needed to prevent the early adsorption of the antibiotic in intestinal medium. Adsorption studies in simulated colonic medium show that the adsorption capacity of chitosan–iron is not modified after encapsulation within pectin beads making clinically feasible the sequestration of residual ciprofloxacin reaching the colon.

Drug/Dye-Loaded, Multifunctional PEG-Chitosan-Iron Oxide Nanocomposites for Methotraxate Synergistically Self-Targeted Cancer Therapy and Dual Model Imaging.

Multifunctional nanocomposites hold great potential to integrate therapeutic and diagnostic functions into a single nanoscale structure. In this paper, we prepared the MTX-PEG-CS-IONPs-Cy5.5 nanocomposites by functionalizing the surface of chitosan-decorated iron oxide nanoparticles (CS-IONPs) with polyethylene glycolated methotraxate (MTX-PEG) and near-infrared fluorescent cyanin dye (Cy5.5). A clinically useful PEGylated anticancer prodrug, MTX-PEG, was also developed as a tumor cell-specific targeting ligand for self-targeted cancer treatment. In such nanocomposites, the advantage was that the orthogonally functionalized, self-targeted MTX-PEG-CS-IONPs-Cy5.5 can synergistically combine an early phase selective tumor-targeting efficacy with a late-phase cancer-killing effect, which was also confirmed by dual model (magnetic resonance and fluorescence) imaging. Furthermore, with the aids of the folate (FA) receptor-mediated endocytosis (able to turn cellular uptake "off" in normal cells and "on" in cancer cells) and pH/intracellular protease-mediated hydrolyzing peptide bonds (able to turn drug release "off" in systemic circulation and "on" inside endo/lysosomes), the MTX-PEG-CS-IONPs-Cy5.5 could deliver MTX to FA receptors-overexpressed cancer cells, showing the improved anticancer activity with the reduced side effects. Together, the MTX-PEG-CS-IONPs-Cy5.5 could act as a highly convergent, flexible, and simplified system for dual model imaging and synergistically self-targeted cancer therapy, holding great promise for versatile biomedical applications in future.

Degradation of four organophosphorous pesticides catalyzed by chitosan-metal coordination complexes.

Three types of chitosan with high (3.40 × 10(6)), medium (2.11 × 10(5)), and low (5.89 × 10(4)) molecular weights were chosen as ligands to synthesize chitosan magnesium, calcium, iron(III), and zinc coordination complexes. Degradation of four organophosphorous pesticides (dichlorvos, omethoate, dimethoate, and chlorpyrifos) by the above complexes in a heterogeneous system was studied using solid-phase extraction (SPE) and gas chromatography (GC). The degradation effect is related to the different types of chitosan, metal, and organophosphorus pesticides (OPs). Complexes of transition metals and the low molecular weight chitosan showed high hydrolytic activity. The chitosan-iron(III) complex was further used to study its catalytic kinetics on the hydrolysis of OPs. At pH 7.0 and 20 °C, the half-life of dichlorvos hydrolyzed by chitosan iron(III) was 52 h, whereas that of spontaneous dichlorvos hydrolysis was 105 h. The degradation ratio of omethoate and dimethoate increased to 38 and 52 %, respectively, which were 34 and 48 % higher than the control after 6 days at pH 7.0 and 20 °C. For all tested conditions, an increase of pH and temperature resulted in a higher degradation rate.

Coated nickel foam electrode for the implementation of continuous electro‐Fenton treatment

ABSTRACTBACKGROUNDElectro‐Fenton technology has already demonstrated its ability to degrade organic pollutants. In this treatment hydroxyl radicals are formed due to the reaction of the iron catalyst along with in situ electrogenerated H2O2. However, one of the main limitations of this system is the iron released in the treated effluent. Therefore, retention of iron is required, and in this study, the use of a new cathode in which the iron is fixed on nickel foam is proposed as a solution to the electro‐Fenton treatment in continuous processes.RESULTSThe retention of iron was ensured by its fixation on nickel foam using chitosan, an eco‐friendly polymer, as coating agent. Different chitosan coatings were tested to optimize the manufacturing process of the new cathode. It was concluded that the best electrode for the electro‐Fenton treatment of different dyes (Poly R‐478 and Lissamine Green B) was obtained using a half‐coating electrode cover with iron–chitosan of medium molecular weight. Furthermore, its reusability was positively evaluated in successive cycles. Finally, a continuous treatment using a fluidized bed reactor was successfully performed for the treatment of dye Lissamine Green B.CONCLUSIONSummarizing, this new cathode is a suitable alternative for the treatment of coloured wastewater by continuous electro‐Fenton treatment. © 2014 Society of Chemical Industry

Adsorption of textile dye Reactive Red 120 by the chitosan–Fe(III)-crosslinked: Batch and fixed-bed studies

This paper presents a study of the use of chitosan–iron(III) crosslinked with glutaraldehyde (Ch-Fe) as an adsorbent for the textile anionic dye Reactive Red 120 (RR120) in batch and fixed-bed systems. The maximum adsorption capacity was calculated from the adsorption isotherms, and well fitted by the Langumir–Freudlich isotherm model. The process followed the kinetic model of pseudo-second-order. In fixed-bed studies, the Thomas, Adams-Bahort and Clark models were applied to the breakthrough curves. The thermodynamic parameters showed that the adsorption process is spontaneous and favorable. The adsorbent can be easily regenerated and reused. The adsorption of the RR120 was optimized using a 33 factorial design, and the initial pH of the dye solution had a significant effect.

Magnetic Chitosan–Iron(III) Hydrogel as a Fast and Reusable Adsorbent for Chromium(VI) Removal

The magnetic chitosan–iron(III) hydrogel (MCh-Fe) was synthesized and characterized by SEM, TG, XRD, and FT-IR and used to remove toxic chromium(VI) (CrVI) from aqueous solution. The adsorption of CrVI onto the MCh-Fe adsorbent was fast and could reach equilibrium in less than 30 min. The adsorption was well described by the pseudo-second-order rate model. The equilibrium isotherm was better matched with the Langmuir model. The adsorption of CrVI onto MCh-Fe was an endothermic and spontaneous process. The loading capacity of CrVI on the adsorbent remained at a high level even after five cycles, showing that MCh-Fe can be used for repeated CrVI removal. Column adsorption results indicated that below 0.5 mg L–1 CrVI was found in the effluent up to about 30 and 350 bed volumes for two wastewaters containing 115.0 and 5.6 mg L–1 CrVI, respectively. The CrVI removal mechanism of MCh-Fe was also investigated.

An amperometric glutathione biosensor based on chitosan–iron coated gold nanoparticles modified Pt electrode

A method is described for development of an amperometric biosensor for determination of glutathione (GSH), by immobilizing covalently a glutathione oxidase (GSHOx) onto the surface of gold coated magnetic nanoparticles (Fe@AuNPs) modified Pt electrode. Chitosan was used to introduce amino groups onto the surface of Fe@AuNPs. The morphology and covalent linkage of GSHOx led to high enzyme loading and better shelf life. The enzyme electrode was characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV), Fourier transform infrared (FTIR) and electrochemical impedance spectroscopy (EIS). The electrode showed maximum response within 4s, when polarized at +0.4V, pH 7.0 and 25°C. There was a linear relationship between electrode response and glutathione concentrations in the range 5.0–4000μmolL−1 with a detection limit of 0.1μmolL−1. An amperometric method of GSH determination was developed using this biosensor. The evaluation studies showed that the method was reliable as mean analytic recoveries of 50μM and 100μM of GSH were 97.5±1.7 and 96.1±1.3 respectively and within and between CVs for glutathione determination in blood RBCs were <2.14% and <2.39% respectively. The biosensor showed 50% loss in its initial activity after its 150 uses over a period 4 months, when stored at 4°C. GSH concentration in hemolysated erythrocytes as measured by the present biosensor was 2.8mmolL−1 in apparently healthy persons.

Dielectric analysis of chitosan–iron composite microspheres suspensions: Access to internal and interface electrokinetic information of microspheres

Iron doped chitosan microspheres (IDM) with different concentrations of iron (wt.%) were prepared and dielectric behavior of the IDM suspensions was investigated in the frequency range from 40Hz to 110MHz. Dielectric spectra of these suspensions showed distinct relaxations at MHz frequency range which are attributed to the interfacial polarization between IDM particle and medium solution. The relaxation varied with the concentration of iron (wt.%) in IDM and the changing trends of relaxation parameters showed that: an appropriate iron doping concentration can increase adsorption capacity of chitosan, however, when the doping concentration exceeds a certain value, the capacity will be reduced. Furthermore, the phase parameters of the suspensions were calculated by using Hanai method. The obtained permittivity ɛp of IDM demonstrates a significant change with the iron concentration (wt.%). In addition, the interfacial electrokinetic parameters, surface conductivity λ, charge density σ and zeta potential ζ, were also estimated from the phase parameters and these parameters indicate that: the interfacial properties between the IDM and continuous medium were little affected by iron concentration in IDM.

Chitosan–iron oxide nano-composite platform for mismatch-discriminating DNA hybridization for Neisseria gonorrhoeae detection causing sexually transmitted disease

Electrochemically fabricated nano-composite film of chitosan (CH)–iron oxide (Fe3O4) has been used to detect gonorrhoea, a sexually transmitted disease (STD) via immobilization of biotinylated probe DNA (BDNA) using avidin–biotin coupling for rapid and specific (mismatch-discriminating) DNA hybridization. The presence of Fe3O4 nanoparticles (∼18nm) increases the electro-active surface area of the nano-biocomposite that provides desirable environment for loading of DNA with better conformation leading to increased electron transfer kinetics between the medium and electrode. The differential pulse voltammetric (DPV) studies have been conducted using BDNA/avidin/CH–Fe3O4/ITO electrode owing to the reduction of the methylene blue (MB) indicator and investigate electron transfer between MB moieties and electrode for one and two-bases mismatch. This STD biosensor is found to have a detection limit (1×10−15M) and a wide dynamic range (from 1×10−16M to 1×10−6M) using the complementary target DNA. In addition, the sensing system can be utilized to accurately discriminate complementary sequence from mismatch sequences.

Dual amplification strategy for the fabrication of highly sensitive amperometric immunosensor based on nanocomposite functionalized interface

An effective electrochemical signal amplification strategy based on bilayer enzyme membrane modification and redox probe immobilization was proposed to construct an amperometric immunosensor. At first, porous deposited gold nanocrystals (DpAu) film was performed on bare glass carbon electrode by electrochemical reduction of gold chloride tetrahydrate (HAuCl 4) solution and then Prussian blue (PB) was electrodeposited on the surface of DpAu film, which acted not only as redox probe but also as the first amplification membrane layer. Following that, gold colloidal nanoparticles doped chitosan–iron oxide nanocomposite was coated on the surface of PB/DpAu film to avoid the leakage of PB and assemble antibody biomolecules. Finally, horseradish peroxidase (HRP) as the second enzyme membrane was employed to block the possible remaining active sites and avoid the nonspecific adsorption. With the excellent electrocatalytic properties of PB and HRP to the reduction of hydrogen peroxide (H 2O 2), the dual amplification of antigen–antibody interaction and the enhanced sensitivity could be achieved. Under the optimal conditions, the linear range of the proposed immunosensor for the determination of α-1-fetoprotein (AFP) was from 0.05 to 300 ng/mL with a detection limit of 0.02 ng/mL (S/N = 3). Moreover, the immunosensor exhibited good selectivity, stability, reproducibility and regeneration.

Chitosan Iron(III) Reduces Phosphorus Levels in Alloxan Diabetes-Induced Rats with Signs of Renal Failure Development

This study evaluates the effect of complex cross-linked chitosan iron-(III) (CH-FeCL) polymer as phosphate binder in renal failure induced by alloxan (150 mg/kg, i.p.) in rats. The animals (male and female) were divided into four groups and received the treatment once a day for 15 days: (i) control group, which received a single injection of saline (3 ml/kg, i.p.) and normal diet; (ii) alloxan group, which received only a dose of alloxan and normal diet; (iii) phosphate (PO4) group, which received diet supplemented with phosphate 1.2%; and (iv) CH-FeCL group, which received diet supplemented with phosphate 1.2% + CH-FeCL 0.5% (0.054% Fe elemental). It was observed that the CH-FeCL treatment did not alter body-weight, relative weight of the organs and haematological parameters in the treated and control groups for both sexes. However, a decrease in serum phosphorus level of the CH-FeCL group was observed after 15 days, compared with the phosphate group in both sexes. The serum iron concentration of the CH-FeCL group did not differ from the control group in either sex. CH-FeCL polymer decreases intestinal phosphate absorption in rats with renal failure and is promising for the treatment of phosphate retention in patients with renal failure.

Column studies on the evaluation of novel spacer granules for the removal of arsenite and arsenate from contaminated water

Decontamination of arsenic ions from aqueous media has been investigated using iron chitosan spacer granules (ICS) as an adsorbent. Drying of beads saturated with a spacer sucrose was considered as simple treatment, to prevent the restriction of polymer network and enhance sorption capacity. The novel sorbent was studied in up flow column experiments conducted at different flow rates, pH and bed depth to quantify the treatment performance. It was found that silicate was more inhibitory than phosphate, and the silicate in groundwater controlled the arsenic removal efficiency. The column regeneration studies were carried out for two sorption–desorption cycles using 0.1 N NaOH as the eluant. TCLP leaching tests were conducted on the arsenic loaded adsorbent which revealed the containment of arsenic-laden sludge can be managed without adverse environmental impact. The developed procedure was successfully applied for the removal of both As(III) and As(V) from arsenic contaminated drinking water samples.

Preparation and evaluation of iron–chitosan composites for removal of As(III) and As(V) from arsenic contaminated real life groundwater

A study on the removal of arsenic from real life groundwater using iron–chitosan composites is presented. Removal of arsenic(III) and arsenic(V) was studied through adsorption at pH 7.0 under equilibrium and dynamic conditions. The equilibrium data were fitted to Langmuir adsorption models and the various model parameters were evaluated. The monolayer adsorption capacity from the Langmuir model for iron chitosan flakes (ICF) (22.47 ± 0.56 mg/g for As(V) and 16.15 ± 0.32 mg/g for As(III)) was found to be considerably higher than that obtained for iron chitosan granules (ICB) (2.24 ± 0.04 mg/g for As(V); 2.32 ± 0.05 mg/g for As(III)). Anions including sulfate, phosphate and silicate at the levels present in groundwater did not cause serious interference in the adsorption behavior of arsenate/arsenite. The column regeneration studies were carried out for two sorption–desorption cycles for both As(III) and As(V) using ICF and ICB as sorbents. One hundred and forty-seven bed volumes of As(III) and 112 bed volumes of As(V) spiked groundwater were treated in column experiments using ICB, reducing arsenic concentration from 500 to <10 μg/l. The eluent used for the regeneration of the spent sorbent was 0.1 M NaOH. The adsorbent was also successfully applied for the removal of total inorganic arsenic down to <10 μg/l from real life arsenic contaminated groundwater samples.

Chitosan–iron oxide nanobiocomposite based immunosensor for ochratoxin-A

The rabbit immunoglobulin antibodies (IgGs) have been immobilized onto nanobiocomposite film of chitosan (CH)–iron oxide (Fe 3O 4) nanoparticles prepared onto indium–tin oxide (ITO) electrode for detection of ochratoxin-A (OTA). Excellent film forming ability and availability of –NH 2 group in CH and affinity of surface charged Fe 3O 4 nanoparticles for oxygen support the immobilization of IgGs. Differential pulse voltammettry (DPV) studies indicate that Fe 3O 4 nanoparticles provide increased electroactive surface area for loading of IgGs and improved electron transport between IgGs and electrode. IgGs/CH–Fe 3O 4 nanobiocomposite/ITO immunoelectrode exhibits improved characteristics such as low detection limit (0.5 ng dL −1), fast response time (18 s) and high sensitivity (36 μA/ng dL −1 cm −2) with respect to IgGs/CH/ITO immunoelectrode.

CHITOSAN--IRON(III)--CROSSLINKING (CH–FeIII–CL) FOR PRE-CONCENTRATION OF PHOSPHATE IN SIMULATED SEAWATER

In this work, the pre-concentration of phosphate on chitosan–iron(III)–crosslinked (CH–FeIII–CL) was investigated in simulated seawater. The results from the sorption experiments demonstrate the possibility of using CH–FeIII–CL to remove phosphate from seawater. Improved analytical performance for phosphate pre-concentration using the CH–FeIII–CL method was obtained compared to the conventional method. Based on the results, the methods will be applied to analyze river water, seawater, groundwater, and industrial water.

Cross-linking chitosan-Fe(III), an oral phosphate binder: studies in vitro and in vivo

The objective was to evaluate the in vitro and in vivo phosphate binding properties of cross-linked chitosan iron (III) (CH-Fe(III)-CL), a potential oral phosphate binder for treating hyperphosphatemia. At equilibrium, the in vitro phosphate binding of CH-Fe(III)-CL was 23.6 mg g −1 for simulated gastrointestinal conditions. In hyperphosphatemic rats, CH-Fe(III)-CL was similar to iron sulfate in reducing serum phosphate by about 35%.

酸性尿毒症物質の経口吸着除去

Dialdehyde cellulose (DAC), modified by chitosan coating (chitosanDAC) and iron chitosan complex, developed as oral sorbents for urea and phosphate removal, were reported in previous papers. In this paper, chitosanDAC, iron chitosancomplex and chitosan were tested for removal of uric acid, quinolinic acid, trans-aconitic acid and 2, 5-furan dicarboxylic acid, which are main acidic substances existed in uremic toxins. In-vitro experiments have shown that chitosanDAC and chitosan remove these acidic substances by adsorption in high rate and capacity. Chronic renal failure rats were fed on the standard diet with or without chitosanDAC (5 % content)for about two months. Rats received chitosanDAC showed 8 % decrease of blood uric acid compared with rats received the normal diet.

Removal of Phosphate from Dilute Phosphate Solution by an Iron Chitosan Complex to Be Used as an Oral Sorbent

Abstract The long-period administration of aluminum-containing phosphate binders for the treatment of hyperphosphatemia has been shown to carry the risk of aluminum accumulation associated with many bone diseases. An iron chitosan complex prepared by chitosan and iron(II) sulfate was examined as an alternative intestinal phosphate binder. In-vitro experiments have shown that the phosphate-binding capacity of iron chitosan increases with increasing the iron content of iron chitosan, the concentration of phosphate, and the pH of the solution. The phosphate-binding capacity of iron chitosan (iron content 32 mg g−1) was over 30 mg g−1 when 10 mg of iron chitosan was admitted to 10 ml of a phosphate solution of 10 mg dl−1 (pH 7.5) at 37 °C for 6 h. This value is much higher than those of aluminum hydroxide, calcium carbonate, etc., which were practically tried before. No elution of the iron from iron chitosan could be detected under these conditions.