The re-bridging of the deficient nerve is the main problem to be solved after the functional impairment of the peripheral nerve. In this study, a directionally aligned polycaprolactone/triiron ...tetraoxide (PCL/Fe3O4) fiber scaffolds were firstly prepared by electrospinning technique, and further then grafted with IKVAV peptide for regulating DRG growth and axon extension in peripheral nerve regeneration. The results showed that oriented aligned magnetic PCL/Fe3O4 composite scaffolds were successfully prepared by electrospinning technique and possessed good mechanical properties and magnetic responsiveness. The PCL/Fe3O4 scaffolds containing different Fe3O4 concentrations were free of cytotoxicity, indicating the good biocompatibility and low cytotoxicity of the scaffolds. The IKVAV-functionalized PCL/Fe3O4 scaffolds were able to guide and promote the directional extension of axons, the application of external magnetic field and the grafting of IKVAV peptides significantly further promoted the growth of DRGs and axons. The ELISA test results showed that the AP-10 F group scaffolds promoted the secretion of nerve growth factor (NGF) from DRG under a static magnetic field (SMF), thus promoting the growth and extension of axons. Importantly, the IKVAV-functionalized PCL/Fe3O4 scaffolds could significantly up-regulate the expression of Cntn2, PCNA, Sox10 and Isca1 genes related to adhesion, proliferation and magnetic receptor function under the stimulation of SMF. Therefore, IKVAV-functionalized PCL/Fe3O4 composite oriented scaffolds have potential applications in neural tissue engineering.
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•IKVAV-grafted magnetic aligned PCL/Fe3O4 scaffolds were successfully prepared.•The scaffolds showed good mechanical properties and magnetic responsiveness.•The scaffolds displays good biocompatibility and orientation-induced behavior of DRG axon.•The scaffolds by SMF promotes NGF release and genes expression related to DRG adhesion and growth.•The study may provide important basis for the preparation of artificial nerve grafts
•Yolk-shell Fe3O4@MOF-5 was prepared by utilizing a simple solvothermal method.•The yolk-shell Fe3O4@MOF-5 shows excellent heterogeneous Fenton-like catalysis.•The yolk-shell Fe3O4@MOF-5 exhibits ...synergies of absorption and degradation.•The porous MOF shell provides a stable micro-environment for degradation of dyes.•The yolk-shell Fe3O4@MOF-5 has good stability and recyclability.
Yolk-shell Fe3O4@MOF-5 nanocomposites were synthesized by utilizing a simple solvothermal method. The physicochemical properties of the yolk-shell Fe3O4@MOF-5 nanocomposites were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) and vibrating sample magnetometer (VSM) methods. The nanocomposites had a catalytic yolk, a hollow cavity and a porous shell. The nanocomposites had relatively high specific surface area of 203 m2 g−1 and showed superparamagnetic property. The catalytic activities of the yolk-shell Fe3O4@MOF-5 nanocomposites were evaluated by using methylene blue dye as a model pollutant. It is demonstrated that the yolk-shell Fe3O4@MOF-5 nanocomposites as a heterogeneous Fenton-like catalyst exhibited excellent catalysis since the internal cavity provided a relatively stable micro-environment for the reaction of the active ·OH radicals and the pollutants on the basis of the confinement effect. Furthermore, the yolk-shell Fe3O4@MOF-5 nanocomposites could be lightly separated from the pollutant solution by an external magnetic field and maintained good catalytic activity after five recycles, indicating the good stability of the nanocomposites.
The goal of this investigation was to develop a new magnetic nanocomposite of walnut shell ash (WSA)/starch/Fe3O4 to remove Cu (II) present in groundwater samples. The desired nanocomposites were ...successfully synthesized by the chemical deposition method. The specific active surface area for pristine WSA and WSA/starch/Fe3O4 magnetic nanocomposites was determined to be 8.1 and 52.6 m2/g, respectively. A central composite design for the response surface method was utilized to study the influence of pH, adsorbent quantity, initial content of Cu (II), temperature, and contact time. This method showed the success of the model to design process variables and to estimate the appropriate response. The P- and F-value determined for the quadratic polynomial model showed the significance and accuracy of the proposed model in examining experimental and predicted data with R2 and Adj.R2 of 0.994 and 0.991, respectively. The Cu adsorption onto WSA and WSA/starch/Fe3O4 obeyed the Freundlich and Langmuir models, respectively. The highest Cu (II) sorption capacity of 29.0 and 45.4 mg/g was attained for WSA and WSA/starch/Fe3O4, respectively. The free energy of Gibbs had a negative value at 25–45 °C indicating that the adsorption process is spontaneous. Also, negative ΔH values for copper adsorption showed that the processes are exothermic. The kinetic adsorption data for WSA and WSA/starch/Fe3O4 followed the pseudo-second order (PSO) model. The ability of the composite adsorbent to remove copper from three groundwater samples showed that it could be reused at least 3 times with appropriate efficiency, depending on the water quality.
Cu ion removal using walnut ash/starch/Fe3O4. Display omitted
•The walnut shell ash (WSA) was composited with starch and Fe3O4.•The BET value for WSA and WSA/starch/Fe3O4 was 8.1 and 52.6 m2/g, respectively.•The Cu removal by WSA/starch/Fe3O4 followed pseudo-second order and Langmuir model.•The Cu sorption capacity of WSA/starch/Fe3O4 was obtained 45.4 mg/g.•Groundwater samples were efficiently treated by WSA/starch/Fe3O4.
Pretreatment is one of the most important steps in the production of bioethanol from renewable feedstocks like lignocellulosic biomass, however, existing pretreatment approaches have some ...limitations. In this context, two different acid-functionalized magnetic nanoparticles (MNPs) i.e. alkylsulfonic acid (Fe3O4-MNPs@Si@AS) and butylcarboxylic acid (Fe3O4-MNPs@Si@BCOOH) were synthesized and evaluated for their efficacy at different concentration in the pretreatment of sugarcane bagasse. It was observed that both of these acid-functionalized MNPs showed concentration-dependent promising catalytic activity as compared to conventional acid pretreatment. Both Fe3O4-MNPs@Si@AS and Fe3O4-MNPs@Si@BCOOH at 500 mg/g of bagasse showed the maximum amount of sugar (xylose) liberated i.e. 18.83 g/L and 18.67 g/L, respectively which are comparatively higher than the normal acid pretreatment (15.40 g/L) and untreated sample (0.28 g/L). Further, both the acid-functionalized MNPs used were recovered by applying magnetic field and reused for next two subsequent cycles of pretreatment. Therefore, such nanotechnology-based approaches can be used as a rapid and eco-friendly alternative method for the pretreatment of a variety of lignocellulosic materials. Moreover, the reuse of the same MNPs for more than one cycle of pretreatment can also help to reduce the cost involved in the process.
•Novel approach has been developed for synthesis of MNPs & acid-functionalized MNPs.•Acid-functionalized MNPs used for the first in pretreatment of sugarcane bagasse.•Same acid-functionalized MNPs can be used for multiple cycles of pretreatments.•Utilization of acid-functionalized MNPs as catalysts is cost effective approach.
The present research comprises the fabrication of magnetic Fe3O4 incorporated chitosan grafted acrylamide and N-vinylimidazole composite hydrogels (CANFe-1 to CANFe-7) via water mediated free radical ...polymerization technique using ammonium persulfate/tetramethyl ethylenediamine as initiator. The prepared magnetic composite hydrogel was characterized by FT-IR, TGA, SEM, XRD, and VSM analysis. A swelling study was performed to understand the swelling behavior and found CANFe-4 to be more efficient with maximum swelling hence entire removal studies were performed with CANFe-4. pHPZC analysis was performed to determine pH sensitive adsorptive removal of cationic dye (methylene blue). pH dependent adsorption of methylene blue was dominant at pH = 8 with a maximum adsorption capacity of 860 mg/g. After the adsorptive removal of methylene blue from aqueous media, a composite hydrogel can conveniently be separated from the solution with the use of an external magnet. Adsorption of methylene blue is well explained with the Langmuir adsorption isotherm and Pseudo-Second-Order kinetic model that validates chemisorption. Moreover, it was found that CANFe-4 could be frequently applied for the adsorptive removal of methylene blue for 5 consecutive adsorption-desorption cycles with 92.4 % removal efficiency. Hence, CANFe-4 offers a promising recyclable, sustainable, robust, and efficient adsorbent for wastewater treatment.
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•Fe3O4@CS/p(AAm/NVIm) MCHs (CANFe-4) was fabricated as an efficient adsorbent for methylene blue removal.•The CANFe-4 exhibits pH dependent adsorption that relies on electrostatic interaction and H-bonding.•The incorporation of Fe3O4 introduces magnetic separation in presence of external magnetic field.•Langmuir adsorption isotherm and Pseudo-Second-Order kinetics were in agreement with obtained experimental data.•The CANFe-4 continues to remove 92.4 % of methylene blue from aqueous media even after five adsorption cycles.
Selective and quantitative detection of different kinds of biocomponents plays an important role in biomedical applications, clinical diagnostics, environmental monitoring, toxicology, regenerative ...medicine and drug delivery. Therefore, multidisciplinary area of magnetic biosensing have been extensively developed in recent years, aiming to create compact analytical devices for non-expensive and low time consuming analysis provided at the point of care by non-skilled personnel. Biological samples exhibit very low magnetic background, and thus highly sensitive measurements of magnetic labels or magnetic nanoparticles enriched units can be performed without further processing. A magnetic biosensor is a compact analytical device in which magnetic transducer converts a magnetic field variation into a change of frequency, current, voltage, etc. Different types of magnetic effects are capable of creating magnetic biosensors with extra high sensitivity. This book describes interesting examples of magnetic materials based biosensors, including the synthesis of model materials for biosensor development, new engineering solutions and theoretical contributions on the magnetic biosensor sensitivity. Book contains 13 research works representing international multidisciplinary teams from Austria, China, Germany, Greece, Iran, Russia, Serbia, Spain, Taiwan and United States of America. It can be useful for PHD students and researches working in the field of magnetic nanomaterials and biomedical applications.
•A novel microfluidic paper-based colorimetric sensor for the detection of bisphenol A (BPA) is developed.•ZnFe2O4 and cellulose fibers in paper are wrapped by molecularly imprinted polymer (MIP) ...membranes successfully.•MIP membranes with high surface area can provide much more multidimensional spaces suitable for the absorption of BPA.•The color change can be observed by naked eyes and quantified by software.
A novel microfluidic paper-based colorimetric sensor for the detection of bisphenol A (BPA) was developed based on the intrinsic peroxidase activity of ZnFe2O4 magnetic nanoparticles (ZnFe2O4 MNPs) and the adsorption capacity of molecularly imprinted polymer (MIP) membranes. In the process, ZnFe2O4 MNPs and cellulose fibers in paper were wrapped by MIP membranes (ZnFe2O4@MIP membranes) successfully. Novel MIP membranes for the recognition of BPA were prepared in polar solvent using acrylamide as the functional monomer and BPA as the template by bulk polymerization, which resulted in a new type of BPA imprinted polymer membranes. Adsorption isotherms model of MIP membranes was employed to describe the isotherms, and maximum adsorption capacity was evaluated. In the presence of 3,3′,5,5′-tetramethylbenzidine (TMB), the as-prepared ZnFe2O4 MNPs peroxidase mimetics was used to catalyze chromogenic reactions and showed the color with respective intensity. Under optimized conditions, the grey intensity was found to be proportional to the BPA concentrations in the range of 10 nM–1000nM (R2=0.9945) with a detection limit of 6.18nM. With the advantages of highly reproducible response, good selectivity and excellent regeneration, the colorimetric sensor holds great potential for portable detection of targets in environmental monitoring, security inspection and complicated matrices.
Iron oxide magnetic nanoparticles (Fe3O4 MNPs) can effectively activate persulfate anions (S2O82−) to produce sulfate free radicals (SO4−), which are a powerful oxidant with promising applications to ...degrade organic contaminants. The kinetics of sulfamonomethoxine (SMM) degradation was studied in the system of Fe3O4 MNPs and S2O82−. A complete removal of the added SMM (0.06mmolL−1) was achieved within 15min with the addition of 1.20mmolL−1 S2O82− and 2.40mmolL−1 Fe3O4 MNPs. There is an optimum concentration of Fe3O4 MNPs because Fe3O4 MNPs may also act as a SO4− scavenger at higher concentrations. It was further observed that the addition of Fe3O4 MNPs in several batches for a given total amount of the activator is favorable to enhancing the degradation of SMM. A degradation mechanism was proposed on the basis of identification of the degradation intermediates of SMM with liquid chromatography combined with mass spectroscopy.
In this study, the intensification of a UVC-based PMS activation treatment is performed by a novel photocatalyst. Using ZnO nanoparticles coupled with activated carbon (AC), impregnated by ...ferroferric oxides (FO, magnetite), as an effective Z-scheme photocatalyst (ZACFO), the effective Bisphenol A (BP-A) removal was attained. Several techniques were applied for the characterization of the as-prepared catalyst and proved the successful preparation of ZACFO. The photocatalytic activity of pristine ZnO was significantly improved after its combination with ACFO. It was found that the fabrication of ZACFO heterostructures could inhibit the charge carriers recombination and also accelerate the charge separation of photo-induced e−/h+ pairs. Under this UVC-based photocatalysis-mediated PMS activation system, ZACFO showed an excellent potential as compared to the single constituent catalysts. The complete degradation of 20 mg/L concentration of BP-A was attained in just 20 min with excellent reaction rate constant of 27.3 × 10−2 min−1. Besides, over 60% of TOC was eliminated by the integrated ZACFO/PMS/UV system within 60 min of reaction. The minor inhibition by most matrix components, the high recycling capability with minor metals’ leaching and the effectiveness in complex matrices, constitute this composite method an efficient and promising process for treating real wastewater samples. Finally, based on the photo-produced reactive intermediates and by-products identified, the Z-scheme photocatalytic mechanism and the plausible pathway of BP-A degradation were proposed comprehensively. The presence and role of radical and non-radical pathways in the decontamination process of BP-A over ZACFO/PMS/UV system was confirmed.
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•A novel Z-scheme, ZnO-based photocatalyst (ZACFO) was prepared to activate PMS.•Excellent synergistic effect was found between PMS and the photocatalyst on BP-A degradation.•The ensuing Z-scheme heterojunction mechanism was explained in detail.•BP-A elimination over ZACFO/PMS/UV occurred by both radical and non-radical pathways.•The ZACFO/PMS/UV system showed high reuse potential in BP-A elimination.
In the present work, polythiophene-coated Fe3O4 nanoparticles (Fe3O4@PTh NPs) have been successfully synthesized. The synthesized Fe3O4@PTh NPs were applied as an efficient sorbent for extraction and ...pre-concentration of several typical plasticizer compounds from environmental water samples. Display omitted
► A novel polythiophene-coated Fe3O4 nanoparticles (Fe3O4@PTh NPs) was synthesized. ► The synthesized Fe3O4@PTh NPs were characterized by using different instruments. ► The Fe3O4@PTh NPs were applied as a sorbent for extraction of several plasticizers. ► After extraction, separation of NPs from solution was achieved by a magnetic field. ► The proposed procedure was applied to analysis of the analytes in real water samples.
In the present work, a novel type of superparamagnetic nanosorbent, polythiophene-coated Fe3O4 nanoparticles (Fe3O4@PTh NPs), have been successfully synthesized. The synthesized NPs were characterized by scanning electron microscopy (SEM), Fourier transform-infrared (FT-IR) spectroscopy, and thermal gravimetric analysis (TGA). The synthesized Fe3O4@PTh NPs were applied as an efficient sorbent for extraction and preconcentration of several typical plasticizer compounds (di-n-butyl phthalate (DBP), di-(2-ethylhexyl) phthalate (DEHP), and dioctyl adipate (DOA)) from environmental water samples. Separation of Fe3O4@PTh NPs from the aqueous solution was simply achieved by applying external magnetic field. Separation and determination of the extracted plasticizers was performed by gas chromatography–flame ionization detection (GC–FID). Several variables affecting the extraction efficiency of the analytes i.e., amount of NPs sorbent, salt concentration, extraction time, and desorption conditions were investigated and optimized. The best working conditions were as follows: amount of sorbent, 100mg; NaCl concentration, 30% (w/v); sample volume, 45mL; extraction time, 10min; and 100μL of ethyl acetate for desorption of the analytes within 2min. Under optimized conditions, preconcentration factors for DBP, DEHP, and DOA were obtained as 86, 194, and 213, respectively. The calibration curves were linear (R2>0.998) in the concentration range of 0.4–100μgL−1 for both DEHP and DOA and 0.7–100μgL−1 for DBP. The limits of detection (LODs) were obtained in the range of 0.2–0.4μgL−1. The intra-day relative standard deviations (RSDs%) based on four replicates were obtained in the range of 4.0–12.3%. The proposed procedure was applied to analysis of water samples including river water, bottled mineral water, and boiling water exposed to polyethylene container (after cooling) and recoveries between 85 and 99% and RSDs lower than 12.8% were obtained.
