A Novel Electrochemical Biosensor Based On Fe3O4 Nanoparticles-Polyvinyl Alcohol Composite for Sensitive Detection of Glucose

In this research, a new electrochemical biosensor was constructed for the glucose detection. Iron oxide nanoparticles (Fe3O4) were synthesized through co-precipitation method. Polyvinyl alcohol-Fe3O4 nanocomposite was prepared by dispersing synthesized nanoparticles in the polyvinyl alcohol (PVA) solution. Glucose oxidase (GOx) was immobilized on the PVA-Fe3O4 nanocomposite via physical adsorption. The mixture of PVA, Fe3O4 nanoparticles and GOx was drop cast on a tin (Sn) electrode surface (GOx/PVA-Fe3O4/Sn). The Fe3O4 nanoparticles were characterized by X-ray diffraction (XRD). Also, Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscopy (FE-SEM) techniques were utilized to evaluate the PVA-Fe3O4 and GOx/PVA-Fe3O4 nanocomposites. The electrochemical performance of the modified biosensor was investigated using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Presence of Fe3O4nanoparticles in the PVA matrix enhanced the electron transfer between enzyme and electrode surface and the immobilized GOx showed excellent catalytic characteristic toward glucose. The GOx/PVA-Fe3O4/Sn bioelectrode could measure glucose in the range from 5 × 10−3 to 30 mM with a sensitivity of 9.36 μA mM−1 and exhibited a lower detection limit of 8 μM at a signal-to-noise ratio of 3. The value of Michaelis-Menten constant (KM) was calculated as 1.42 mM. The modified biosensor also has good anti-interfering ability during the glucose detection, fast response (10 s), good reproducibility and satisfactory stability. Finally, the results demonstrated that the GOx/PVA-Fe3O4/Sn bioelectrode is promising in biosensor construction

Improved Anticancer Effect of Magnetite Nanocomposite Formulation of GALLIC Acid (Fe₃O₄-PEG-GA) Against Lung, Breast and Colon Cancer Cells

Lung cancer, breast cancer and colorectal cancer are the most prevalent fatal types of cancers globally. Gallic acid (3,4,5-trihydroxybenzoic acid) is a bioactive compound found in plants and foods, such as white tea, witch hazel and it has been reported to possess anticancer, antioxidant and anti-inflammatory properties. In this study we have redesigned our previously reported anticancer nanocomposite formulation with improved drug loading based on iron oxide magnetite nanoparticles coated with polyethylene glycol and loaded with anticancer drug gallic acid (Fe₃O₄-PEG-GA). The in vitro release profile and percentage drug loading were found to be better than our previously reported formulation. The anticancer activity of pure gallic acid (GA), empty carrier (Fe₃O₄-PEG) nanocarrier and of anticancer nanocomposite (Fe₃O₄-PEG-GA) were screened against human lung cancer cells (A549), human breast cancer cells (MCF-7), human colon cancer cells (HT-29) and normal fibroblast cells (3T3) after incubation of 24, 48 and 72 h using (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) MTT assay. The designed formulation (Fe₃O₄-PEG-GA) showed better anticancer activity than free gallic acid (GA). The results of the in vitro studies are highly encouraging to conduct the in vivo studies

Iron Oxide Based Magnetic Nanocomposites: Removal of Inorganic and Organic Water Contaminants and Antimicrobial Properties

In the current scenario, most of the researcher try to prepared novel and cost-effective nanomaterials for wastewater treatment especially discharge from industrial and domestic water, drinking water and contaminated water. A worldwide growing population is one of the major sources of water pollution. The overall thesis demonstrates an extensive view of the use of nanomaterials in water purification using functionalized iron oxide nanomaterials by adsorption of inorganic and organic contaminants. In the present work, we have prepared iron oxide nanoparticles (Fe3O4) and iron oxide-based nanomaterials such as Fe3O4-TSPED-Tryptophan, Fe3O4-GG, Fe3O4-APTES-EDTA and GO-Fe3O4-APTES of various morphology using precipitation methods. The synthesized nanomaterials were analyzed using FT-IR, XRD, TEM, FE-SEM, VSM, BET surface area, TGA, Zeta potential, Raman and UV-Vis Spectroscopy techniques and were used as effective adsorbent towards heavy metal ions and organic dyes from aqueous solution. In the first project, we use amino acid (Tryptophan) functionalized iron oxide nanomaterial and TSPED act as a linking agent in between them. The results revealed that the Fe3O4-TSPED-Tryptophan shows greater affinity towards Congo Red (CR) dye adsorption and antibacterial properties. The adsorption efficacy of the dye is assessed by varying various parameters such as pH, dye concentration, adsorbent dose and time. The adsorption isotherm is found to follow Langmuir isotherm model and the rate of adsorption well fitted to pseudo-second-order kinetics. We further checked the antibacterial activity of the dye against gram-negative (Escherichia coli) and gram-positive (Bacillus subtilis) bacterial strain. FTT nanocomposite responds positively towards antibacterial activity. In the same direction, the second project, functionalized Guar-gum (GG) on the surface of iron oxide (Fe3O4) nanoparticles were synthesized via conventional co-precipitation method. The efficiency of the nanocomposite was investigated towards the adsorption of different dyes such Congo red (CR), Malachite green (MG), Methylene blue (MeB), Methyl orange (MO), Eriochrome Black T (EBT), Methyl blue (MB) and Rhodamine B (Rhb). Among which CR dye shows adsorption efficiency of 97% using the prepared nanocomposite. The presence of -NH2 in the CR dye is responsible for the efficient adsorption, as it easily forms hydrogen bonding with the surface hydroxyl group of Fe3O4-GG. The optimum condition for dye removal efficiency using Fe3O4-GG has been investigated by varying different factors such as the influence of pH, the initial concentration of dye, adsorbent dose and influence of contact time. Moreover, the adsorption procedure was studied with various adsorption isotherms (Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, and Elovich isotherm). Among all isotherm model, Langmuir isotherm model is best fit for CR adsorption. The CR dye adsorption limit was found to be, qm=60.24 mg/g. The dye adsorption rate follows the pseudo-second-order kinetic model. For the removal of inorganic contaminants, in the third project advancement of an efficient and cost-effective method for heavy metal removal from contaminated water utilizing Fe3O4-APTES-EDTA nanocomposite, a productive reusable adsorbent, is explained in this study. The novel Fe3O4-APTES-EDTA nanocomposite was prepared by three-step process such as (a) firstly Fe3O4 nanoparticle was prepared by chemical co-precipitation method, (b) secondly, the silane coating on the surface of magnetic Fe3O4 cores using linking agent APTES was done which provide amino group (–NH2) for linking with the EDTA molecule and (c) finally, EDTA molecules functions as inclusion sites and a selective containers for trapping different heavy metal ions. Fe3O4-APTES-EDTAis found to be a good adsorbent for Pb2+, Cd2+, Ni2+, Co2+ and Cu2+ removal with a higher adsorption capacity. The maximum adsorption capacity of Pb2+, Cd2+, Ni2+, Co2+, Cu2+ are found to be 11.31, 13.88, 7.64, 4.86 and 78.67 mg/g, respectively. The adsorption and desorption cycle was studied for five cycles with minimal loss of efficiency. In the fourth project, amino silane magnetic nanocomposite decorated on graphene oxide (GO-Fe3O4-APTES) was successfully prepared by organic transformation reaction followed by co-precipitation method. GO-Fe3O4-APTES material was highly selective for Chromium (VI) removal from aqueous solution. About 91 % of Chromium (VI) was removed at pH 3, 160 rpm of shaking speed, 0.3 g/L of adsorbent dose and 10 hours of contact time. The adsorption process of Chromium (VI) on GO-Fe3O4-APTES follows Pseudo-second-order kinetic and Langmuir isotherm model because of the high correlation coefficient value (R2=0.99). The maximum adsorption capacity (qm) of GO-Fe3O4-APTES was observed at 60.53 mg/g. The synthesized material was desorbed with 0.5 M NaOH and recycled up to five cycles. After five cycles, the removal efficiency of chromium (VI) possesses high efficacy towards-Fe3O4-APTES. Mechanistically, adsorption of Chromium (VI) follows strong electrostatic attraction between adsorbate and adsorbent. GO-Fe3O4-APTES has potential adsorbent for the adsorption of chromium (VI) in wastewater treatment. Furthermore, the Fe3O4-APTES were tested for antibacterial properties against gram-negative (Escherichia coli) and gram-positive (Bacillus subtilis) bacterial strain. The synthesized material responds positively towards antibacterial activity

Crumpled Graphene Oxide: Aerosol Synthesis and Environmental Applications

Environmental technologies, such as for water treatment, have advanced significantly due to the rapid expansion and application of nanoscale material science and engineering. In particular, two-dimensional graphene oxide (GO), has demonstrated considerable potential for advancing and even revolutionizing some of these technologies, such as engineered photocatalysts and membranes. To realize such potential, an industrially scalable process is needed to produce monomeric and aggregation-resistant GO nanostructures/composites, in addition to new knowledge of material properties, behavior, and performance within an environmental context. Research presented in this thesis addresses both scientific and engineering gaps through the development of a simple, yet robust aerosol-based synthesis approach and demonstrations of two applications, photocatalysts and membranes. The aerosol-based process was developed to engineer the 2D GO nanosheets into 3D crumpled balls (crumpled GO, CGO), which have excellent aggregation- and compression-resistant properties, while allowing for the incorporation (encapsulation) of other (multi)functional particles inside. The five focus areas of this dissertation are: 1) Crumpling and thermal reduction of GO nanosheets in aerosolized droplets, 2) (Multi)functional nanocomposite synthesis, 3) Colloidal behavior in water as a function of material properties and selected environmental constituents/conditions, 4) Photocatalytic applications, 5) Composite assemblies/nanoscale fillers for advanced water treatment membranes. Results reveal that the evaporation rate of water droplets plays a critical role in controlling the crumpling process, and thermal reduction leads to temperature-dependent removal of oxygen functional groups. (Multi)functional composites can be achieved through encapsulation of single or multiple types of nanoparticles, such as TiO2, magnetite, and silver. Morphological transformation by crumpling, increased degree(s) of oxidation, and presence of natural organic matters act to enhance the stability of GO in water. CGO-TiO2 composites are shown to possess superior aqueous-based photocatalytic properties, including efficient photo-reduction reaction pathways. Furthermore, assemblies of CGO nanoparticles show superior permeation, separation, and reactive (photo-reactive and antimicrobial) properties. In addition, in situ surface-based photocatalyzed synthesis of Ag nanoparticles at the surface of membrane assemblies, is demonstrated as an approach to (re)generate, thus maintain, enhanced antimicrobial activity. This work identifies and solves several key issues regarding the industrially attractive processing and applications of (crumpled) graphene-based materials for water treatment technologies. Knowledge obtained, as part of this thesis, will impact aerosol processing of materials, environmental nanotechnology, environmental catalysis, and water treatment membrane technology, among other fields

Synergistic interaction of clusters of iron oxide nanoparticles and reduced graphene oxide for high supercapacitor performance

Supercapacitors have been recognized as one of the more promising energy storage devices, with great potential use in portable electronics and hybrid vehicles. In this study, a composite made of clusters of iron oxide (Fe3O4-γFe2O3) nanoparticles and reduced graphene oxide (rGO) has been developed through a simple one-step solvothermal synthesis method for a high-performance supercapacitor electrode. Electrochemical assessment via cyclic voltammetry, galvanostatic charge–discharge experiments, and electrochemical impedance spectroscopy (EIS) revealed that the Fe3O4-γFe2O3/rGO nanocomposite showed much higher specific capacitance than either rGO or bare clusters of Fe3O4-γFe2O3 nanoparticles. In particular, specific capacitance values of 100 F g−1, 250 F g−1, and 528 F g−1 were obtained for the clusters of iron oxide nanoparticles, rGO, and the hybrid nanostructure, respectively. The enhancement of the electrochemical performance of the composite material may be attributed to the synergistic interaction between the layers of graphene oxide and the clusters of iron oxide nanoparticles. The intimate contact between the two phases eliminates the interface, thus enabling facile electron transport, which is key to attaining high specific capacitance and, consequently, enhanced charge–discharge time. Performance evaluation in consecutive cycles has demonstrated that the composite material retains 110% of its initial capacitance after 3000 cycles, making it a promising candidate for supercapacitors.Ministerio de Ciencia e Innovación | Ref. PID2020-119242RB-I00Xunta de Galicia | Ref. ED431B 2021/14Ministerio de Economía y Competitividad | Ref. PID2020-113704RB-I00Xunta de Galicia/FEDER | Ref. IN607A 2018/5Xunta de Galicia | Ref. ED431G 2019-06Interreg España-Portugal | Ref. 0712_ACUINANO_1_EInterreg España-Portugal | Ref. 0624_2IQBIONEURO_6_

Novel Graphene Oxide Based Nanocomposites: Synthesis and Application Towards Adsorptive Removal of Toxic Inorganic/Organic Pollutants from Aqueous Media

In this doctoral work, we have synthesized a series of GO based composite nanoadsorbents such as MgO-MgFe2O4 decorated GO (MgO-MgFe2O4/GO), amine functionalized GO mounted with ZnO-ZnFe2O4 (NH2-GO/ZnO-ZnFe2O4), AlOOH-FeOOH nanorods functionalized GO (GO/AlOOH-FeOOH) and GO/g-C3N4 decorated with Fe3O4 (GO/g-C3N4-Fe3O4) nanomaterials by using hydrothermal method. Then the prepared GO based metal oxide nanocomposites were used as novel adsorbent for adsorption study of inorganic pollutants such as fluoride ions (F-), hexavalent chromium (Cr(VI)), arsenate (As(V)) and organic pollutants like methylene blue (MB) dye, tetracycline (TC) antibiotic from water. The formation, composition, bonding, crystalline phase, surface morphology, size, and surface area of these prepared nanocomposites were analyzed by XRD, FTIR, Raman, XPS, FESEM, HRTEM, and BET analytical techniques. Batch adsorption experiments were carried out under various conditions including pH, time, concentration, adsorbent dose and temperature. The synthesized MgO-MgFe2O4/GO magnetic nanocomposite was used as adsorbent for removal of F- ions from water. The maximum adsorption capacity for F- ions removal is found to be 34 mg/g, which is higher as comparable to MgO-Fe2O3 nanocomposite. The amine functionalized GO decorated with ZnO-ZnFe2O4 (NH2-GO/ZnO-ZnFe2O4) nanocomposite material was used for remediation of Cr (VI) from water. It was observed that introduction of NH2 groups to GO/ZnO-ZnFe2O4 nanocomposite play a very important role for remediation of hexavalent chromium with a maximum uptake capacity of 109.89 mg/g. Apart from this we have also prepared GO/AlOOH-FeOOH composite nanomaterials by one step hydrothermal method and have used for decontamination of arsenate (As(V)) ions from water. Experimental finding reveals that the prepared GO based nanocomposite material is highly efficient for remediation of As(V) ions from water. Furthermore, we have also synthesized GO/g-C3N4 (graphitic carbon nitride) 2D layered composite materials decorated with Fe3O4 nanoparticles and have used for removal of methylene blue (MB) dye and tetracycline (TC) antibiotic from aqueous media. It was found that the adsorption of TC and MB was pH dependent and maximum adsorption capacities of 120 and 220 mg/g were achieved for TC and MB respectively. All the prepared GO based nanoadsorbents were regenerated and reused up to 5 successive cycles without major loss in their sorption capacity. From the obtained experimental results, plausible adsorption mechanism has been proposed for all adsorption process

Systematic review on applicability of magnetic iron-oxides integrated photocatalysts for degradation of organic pollutants in water

Owing to biocompatibility, abundance, and low cost, magnetic iron oxides are well suited for the design of efficient and magnetically separable photocatalysts for water treatment. This review presents a detailed survey of magnetic iron oxide–integrated photocatalysts (MIOIPs), in which we have discussed essential conditions needed for designing of efficient MIOIPs for water purification. The synthesis methods and detailed experimental setups for fabrication of MIOIPs were discussed, and the integration manners of iron oxides (Fe2O3, Fe3O4, FeO, and ferrites) with binary, ternary, and quaternary non-magnetic photocatalysts have been categorized. The mechanistic view of enhanced photocatalytic activity caused by different MIOIPs under various light sources was also elaborately argued. The role of various reactive species in photocatalytic oxidative degrading of organic pollutants was investigated. Altogether, this review article has compressively considered and discussed various signs of advancements made toward the synthesis of MIOIPs and their stability, recyclability, and catalytic efficacy for wastewater treatment

Review Article: Synthesis of Fe3O4 Nanoparticle and Its Application for Glassy Carbon Electrode Modification

Nanomaterials have various unique properties and characteristics so that they can apply in many sectors. One of the most popular nanoparticles today is magnetite nanoparticles. Magnetite particles have several properties such as being super magnetic, having a high saturation field, chemical stability, biocompatibility, and low production costs. The purpose of this article is to review the synthesis of magnetite nanoparticles and their application to Glassy Carbon Electrode (GCE) modification. This modified GCE can applied as an electrochemical sensor to detect various organic and inorganic substances. In this study, type synthesis methods of magnetite nanoparticles which taken from kind literature well investigation include coprecipitation, sol-gel, microemulsion, hydrothermal, and thermal decomposition. The five routes have their respective advantages and disadvantages. Then the nano magnetite made can applied to modify the GCE as an electrochemical sensor that can detect uric acid, bacteria, and even metals dissolved in water

Nanomaterials with Tailored Magnetic Properties as Adsorbents of Organic Pollutants from Wastewaters

Water quality has become one of the most critical issue of concern worldwide. The main challenge of the scientific community is to develop innovative and sustainable water treatment technologies with high efficiencies and low production costs. In recent years, the use of nanomaterials with magnetic properties used as adsorbents in the water decontamination process has received considerable attention since they can be easily separated and reused. This review focuses on the state-of-art of magnetic core-shell nanoparticles and nanocomposites developed for the adsorption of organic pollutants from water. Special attention is paid to magnetic nanoadsorbents based on silica, clay composites, carbonaceous materials, polymers and wastes. Furthermore, we compare different synthesis approaches and adsorption performance of every nanomaterials. The data gathered in this review will provide information for the further development of new efficient water treatment technologies.Fil: Peralta, Marcos Emanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas. Universidad Nacional del Comahue. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas; ArgentinaFil: Ocampo, Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas. Universidad Nacional del Comahue. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas; ArgentinaFil: Funes, Israel German Aristoteles. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigaciones en Toxicología Ambiental y Agrobiotecnología del Comahue. Universidad Nacional del Comahue. Facultad de Ciencias Agrarias. Centro de Investigaciones en Toxicología Ambiental y Agrobiotecnología del Comahue; ArgentinaFil: Onaga Medina, Florencia Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigaciones en Toxicología Ambiental y Agrobiotecnología del Comahue. Universidad Nacional del Comahue. Facultad de Ciencias Agrarias. Centro de Investigaciones en Toxicología Ambiental y Agrobiotecnología del Comahue; ArgentinaFil: Parolo, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigaciones en Toxicología Ambiental y Agrobiotecnología del Comahue. Universidad Nacional del Comahue. Facultad de Ciencias Agrarias. Centro de Investigaciones en Toxicología Ambiental y Agrobiotecnología del Comahue; ArgentinaFil: Carlos, Luciano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas. Universidad Nacional del Comahue. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas; Argentin