Formation Of Iron Oxide Nanoparticles Research Articles

Green synthesis, characterization and drug-loaded iron oxide nanoparticles derived from Nerium oleander flower extract as a nanocarrier for in vitro antibacterial efficacy

Application of drug conjugated iron oxide hematite (α-Fe2O3) nanoparticles are of tremendous interest in biomedicine nowadays. Meanwhile, green production of iron oxide nanoparticles is gaining favour due to its sustainability, ease of usage, and biocompatibility. Therefore, this work reports on the use of hexahydrate ferric chloride and nerium oleander flower extract to synthesize nanoscaled hematite (α-Fe2O3) iron oxide particles conjugated with various drugs for antibacterial agents. Diverse morphological, physicochemical, structural, optical, and magnetic characteristics have been characterized using FESEM, EDX, XRD, UV–vis, FTIR, Raman and vibrating sample magnetometer. The synthesis of the polyshaped iron oxide nanoparticles, with average sizes ranging from 47.2 ± 20 nm, was accomplished. Furthermore, temperature-dependent variations in magnetic behavior were observed during calcination. The XRD and Raman spectra revealed hematite (α-Fe2O3) type formation of iron oxide nanoparticles. Only calcinated IO-NPs at high temperatures (700 °C) demonstrated low coercivity and residual magnetism, which revealed weak ferromagnetic ordering; other calcinated samples, including nascent ones, showed incredibly weak ferromagnetic ordering. Besides, the effectiveness of drug-encapsulated iron oxide nanoparticles against bacteria in vitro was examined. It was interesting to observe that gentamycin-coated IO-NPs tended to be more susceptible to S. aureus than E. coli bacteria, but streptomycin-conjugated IO-NPs showed the reverse trend. However, as compared to the nascent sample and the high temperature (700 °C) calcinated sample, both antibiotic-loaded IO-NPs displayed better inhibitory abilities.

Hybrid polyionic complexes as nanoreactors for the synthesis of iron oxide nanoparticles: From size control to modulation of magnetic and catalytic properties

Hybrid polyion complexes (HPICs) obtained from the complexation in aqueous solution of a double hydrophilic block copolymers and metal ions can act as efficient precursors for the controlled synthesis of hybrid nanoparticles. Hence, HPICs based on a mixture of ferrous and ferric ions with poly(ethylene oxide)-block-poly(acrylic acid) were used to initiate, after the addition at 70 °C of a solution of NH4OH, the formation of iron oxide nanoparticles. The careful choice of the molar ratio between polymer and metal ions within HPICs enables to tune the morphology and size of the obtained iron oxide nanoparticles while maintaining the same surface composition. This control of size and composition was further used to highlight the relationship between the size of these particles and their catalytic and magnetic properties.

Iron-Phthalocyanine Based Oxygen Reduction Reaction Electrocatalyst: Structure-Performance Relationship Evolution during Pyrolysis

Fuel cells efficiently convert hydrogen into green electricity however the key bottleneck in their deployment lies at the cathode where oxygen reduction reaction (ORR) exhibits sluggish kinetics and requires high loading of precious metals.In this view, Iron-Nitrogen-Carbons (Fe-Nx-Cs) are promising electrocatalysts to replace expensive and scarce noble metals currently used for the ORR. Fe-Nx-Cs are typically synthesized through pyrolysis using iron, nitrogen and/or carbon precursors of diverse nature. However, in general, pyrolysis is a process poorly understood despite recently a couple of manuscripts with in-situ investigations that have been presented [1-2]. The pyrolysis process defines the structural and chemical evolution of the electrocatalyst that ultimately governs its overall electroactivity. Therefore, in this study, the influence of pyrolysis conditions i.e. temperature (200-1000 °C) and atmosphere (Ar or Ar/H2) on the morphological and superficial development of electrocatalyst was elucidated that initially consisted of Iron (II) Phthalocyanine (FePc) mixed with Ketjen Black 600. The morphological and chemical features were then correlated with the electrochemical performance in alkaline and acidic media through a structure-to-property relationship. In-depth analysis showed that pyrolysis conditions significantly affect the nature and proportion of active Fe-based and nitrogen-based moieties that collaboratively determine the pathway and kinetics of the ORR in acid and alkaline media. X-ray diffraction (XRD) showed that reducing atmosphere (Ar/H2) inhibits the crystallographic growth of Fe-containing nanoparticles. In parallel, the neutral atmosphere (Ar) enhanced the aggregation of Fe into oxides as diffraction peaks corresponded to Fe3O4 after a pyrolysis temperature of 600°C. High-resolution-transmission electron microscopy (HR-TEM) showed the formation of nanoparticles and oxides at temperatures above 600°C. X-ray photoelectron spectroscopy (XPS) revealed multitudinous nitrogen-based moieties with varying proportions in the Fe-Nx-C electrocatalysts developed under different pyrolysis conditions. Interestingly, the samples pyrolyzed in Ar/H2 showed an increasing trend of Fe-Nx with respect to a pyrolysis temperature whereas, in Ar-pyrolysed samples, Fe-Nx started plummeting after 600°C. On the other hand, graphitic nitrogen increased prominently after 700°C in both pyrolytic conditions. Using a rotating ring disc electrode (RRDE), the dependence of performance parameters on the chemical and structural features that evolved during the pyrolysis was clarified. Particularly, in acidic media (0.5 M H2SO4), Fe-Nx-C synthesized at 600 ºC under both Ar and Ar/H2 conditions demonstrated higher electrocatalytic activity, with half-wave potentials (E1/2) of ≈ 0.70-0.72 V (vs RHE) while maintaining the direct tetra-electronic ORR (low peroxide production). A similar trend was witnessed in an alkaline media (0.1 M KOH) but with relatively higher performance than in acid media. The highest onset potentials and E1/2 observed in alkaline media were obtained by the Fe-Nx-Cs pyrolyzed at 600°C and 700 ºC in both atmospheres i.e. Ar (E1/2 ≈ 0. 89 V vs RHE) and Ar/H2 (E1/2 ≈ 0. 87 V vs RHE). A prompt reduction in the performance was highlighted at higher pyrolysis temperatures where an increase in peroxide yield might be related to the formation of iron oxide nanoparticles. This work presents a novel insight into the evolution of Fe-Nx-C electrocatalysts during pyrolysis with optimum performance.

Kinetic formation of iron oxide nanoparticles using un- and γ-irradiated singular molecular precursor of Tris(pentanedionato)iron(III) complex

Iron oxide nanoparticles were synthesized from tris(pentanedionato)iron(III) singular molecular precursor through pyrolysis in static air. FT-IR, XRD, TGA, BET and SEM/EDS techniques were used to follow the reactions and identify the products. Single crystalline iron oxide sizes were found to be 18.23 ± 0.23, 16.42 ± 0.21, and 13.964 ± 0.11 nm using Scherrer equation, and the BET surface area were measured to be 110.909, 121.352, and 153.9911 m2g−1 for the corresponding iron oxides obtained through pyrolysis of un-irradiated and γ irradiated tris(2,4 pentanedionato)iron(III) with 100 and 300 kGy, respectively. Nonisothermal kinetics formation of iron oxide nanoparticles over the thermal decomposition of un-irradiated and γ-irradiated tris(pentanedionato)iron(III) molecular precursor with 100 and 300 kGy total γ-ray doses were investigated under air flow with a heating rate of 5, 10, 15, 20, and 25 °C/min, from 25 °C to 500 °C. Kinetic parameters were attained through model-fitting and model-free approaches, and artificial isokinetic relationship (IKR) for multi-step processes. The decomposition for both un-irradiated and γ-irradiated tris(pentanedionato)iron(III) molecular precursor with 100 and 300 kGy total γ-ray doses proceed over one major step with two-dimensional diffusion (bi-dimensional particle shape) Valensi equation (D2).

Synthesis and Characterization of Core-Shell Mesoporous Iron oxide Magnetic Nanoparticles using Modified Co-Precipitation Method

In recent era, development of nanotechnology is an art of delivery of drug by improving its compatibility, effectiveness and efficacy. Among all nanoparticles, magnetic nanoparticles play a predominant role to shows their targeted drug delivery using a magnetic field, also helps to diagnose the diseases like cancer. The present study included preparation of four different mesoporous nanoparticles using the Pluronic block copolymer P123 as a surfactant template, then insert iron oxides using co-precipitation method. The resulted formed mesoporous magnetic nanoparticles are examined for structural characters by using FTIR, XRD, HRSEM and Elemental Mapping techniques. The results of X-ray diffraction (XRD) showed that the formed composites conserved ordered mesoporous structure after the formation of iron oxide nanoparticles in the pores. FTIR results indicated that the surface contains silanol group and Fe–O on the surface of the materials at 1060 cm-1 and 1020 cm-1 peaks respectively. Scanning electron microscopy (SEM) results showed that all mesoporous magnetic nanoparticles within the range of size from 50 to 100nm also possessed a regular spherical shape. These particles possessed high surface area, high pore volume and showed magnetic response sufficient for drug targeting in the presence of an external magnetic field. Elemental mapping data indicated about the percentage of all elements present in the mesoporous materials. We concluded that all four types of magnetic nanoparticles are structurally arranged in their structure with sufficient percentage of elements on their particle surface along with good size range. Further loading of drug into all types of magnetic nanoparticles decides the loading efficiency, stability and drug release nature.

Large eddy simulation of iron oxide formation in a laboratory spray flame

Iron oxide nanoparticles are very interesting for many applications in different industrial sectors. A promising process to manufacture these nanoparticles is flame spray pyrolysis (FSP). A lack of understanding of the individual sub-processes in FSP makes it challenging to tailor nanoparticle properties. This work provides insights into the formation of iron oxide nanoparticles in a turbulent spray flame using Large Eddy Simulations (LES), which are based on a comprehensive model, including customized submodels. Highlights are the adaption of a turbulent combustion model and a bivariate hybrid method of moments for modeling nanoparticle dynamics. The work focuses on the SpraySyn burner, which is a standardized laboratory burner and was operated with a precursor-solvent mixture of ethanol and iron(III) nitrate nonahydrate. For studying the relevance of precursor chemistry, LES using an evaporation-limited precursor chemistry model is compared with a model that includes detailed iron chemistry. A further novelty is the inclusion of adsorption in the simulation, which defines a third model for comparison. Sufficient validation is achieved for the undoped LES using experimental data from the literature. A strong impact of the detailed iron chemistry and adsorption is found on the precursor consumption and the aggregate and primary particle formation. Comparing the particle diameters with experimental measurements from the literature and data generated for this work is found unsuitable to asses the precursor chemistry model and revealed an urgent need for future experimental and numerical research. This work serves as a step forward in realizing a reliable model.

Large eddy simulation of iron(III) oxide nanoparticle synthesis in spray flames

The SpraySyn burner has been developed to investigate nanoparticle synthesis from spray flames by various diagnostic methods and simulations from research groups within the DFG (German Research Foundation) priority program SPP1980. We investigate the formation of iron oxide nanoparticles from iron nitrate dissolved in a mixture of ethanol and ethyl hexanoic acid. In the SpraySyn experiment, the nanoparticle precursor solution is injected and atomized via an air-blast nozzle, surrounded by a pilot flame. The solvent itself is combustible, such that the droplets evaporate at high heating rates in a highly reactive environment. We investigate the synthesis flame in large eddy simulations. The liquid droplets are described by Lagrangian particles, and gas-phase combustion is modeled by the flamelet-generated manifold approach with adaptations for particle inception. The nanoparticle dynamics are predicted by three models: a monodisperse model, a bimodal model, and a sectional model. The monodisperse and bimodal models account in terms of number-, surface-, and volume-concentration from inception, coagulation, and sintering processes, while the sectional model accounts for inception and coagulation and provides the particle size distribution. The comparison of nanoparticle sizes with the in-situ measurements shows that the bimodal model can be a suitable alternative approach to the computationally expensive sectional model.

The effect of processing design and the stabilizing effect of nanostructures on the swelling and adsorption properties of polyvinylpyrrolidone macroporous ferrogels obtained through a cryogenic route

AbstractThis paper reports the synthesis of macroporous polyvinylpyrrolidone (PVP) hydrogels modified with in‐situ generated magnetic nanoparticles (NPs). The hydrogels were formed by an optimized thermally induced crosslinking route, initiated by the presence of ammonium persulfate, whereas the macroporosity was created through a cryogenic technique. Crosslinking stabilizes the three dimensional (3D) gel structure, allowing the replacement of expensive and time‐consuming lyophilization steps in favor of simpler drying procedures at atmospheric pressure. The in‐situ formation of iron oxide NPs (IONPs) was achieved through oxide precursors impregnation followed by precipitation of the IONPs in the highly swellable hydrogels. This reaction was performed by addressing two strategies, namely, before or after cryogenic processing, to evaluate its effect on the final swelling and adsorption properties of the gel matrices. It is demonstrated that the inclusion of the magnetic NPs before cryo‐structuring allows the stabilization of the gel against collapse, favoring the conservation of a highly swellable environment. The synergy between the adsorption capacity of the IONPs and the high swelling of the macroporous structure allows obtaining materials with potential in adsorption processes. Preliminary analyses showed that macroporous samples obtained with 32 wt% IONPs led to methylene blue (MB) adsorption capacities as high as 400 mg dye/g ferrogel, for dye concentrations as low as 10 mg/L. These results show that the use of an adequate strategy for the processing of macroporous ferrogels can be of high importance in the design of new adsorbents and superabsorbent hydrogels.

Cubic Mesocrystal Magnetic Iron Oxide Nanoparticle Formation by Oriented Aggregation of Cubes in Organic Media: A Rational Design to Enhance the Magnetic Hyperthermia Efficiency

Cubic Mesocrystal Magnetic Iron Oxide Nanoparticle Formation by Oriented Aggregation of Cubes in Organic Media: A Rational Design to Enhance the Magnetic Hyperthermia Efficiency

Transfection of clMagR/clCry4 imparts MR-T2 imaging contrast properties to living organisms (E. coli) in the presence of Fe3+ by endogenous formation of iron oxide nanoparticles.

Rapid development of medical imaging, such as cellular tracking, has increased the demand for "live" contrast agents. This study provides the first experimental evidence demonstrating that transfection of the clMagR/clCry4 gene can impart magnetic resonance imaging (MRI) T2-contrast properties to living prokaryotic Escherichia coli (E. coli) in the presence of Fe3+ through the endogenous formation of iron oxide nanoparticles. The transfected clMagR/clCry4 gene markedly promoted uptake of exogenous iron by E. coli, achieving an intracellular co-precipitation condition and formation of iron oxide nanoparticles. This study will stimulate further exploration of the biological applications of clMagR/clCry4 in imaging studies.

Iron Oxide Nanoparticles Preparation by Using Homemade Hydrothermal Pyrolysis Technique with Different Reaction Times

In this research, iron oxide nanoparticles were prepared by a new hydrothermal pyrolysis technique at different reaction times. X-ray diffractometer (XRD) characterization showed that the nanoparticles have high crystallinity with a combination of two crystal phases maghemite and magnetite, as the reaction time increase the ratio of magnetite phase to maghemite phase increased. The morphological properties of the samples showed an increase in the particle size from 58 to 108 nm due to the single domain–multidomain transition as showed by scanning electron microscope (SEM). Electron Dispersive X-ray (EDX) spectra showed only peaks of oxygen and iron that verified the formation of iron oxide nanoparticles. The Fourier transform infrared spectroscopy (FT-IR) showed that the absorption peaks at about 578 cm-1 and 630 cm-1 correspond to the stretching modes of the Fe-O in magnetite, as the reaction time increased the peak around 630 cm-1 decreased due to the magnetite phase only. Finally, all the results showed the formation of iron oxide nanoparticles by this new technique that merges spray pyrolysis and hydrothermal techniques with many advantages such as spraying successive parameters in a short time, high-speed, good homogeneity, and pure material with small particle size.

Physico-Chemical Study on Heat Transfer Property of Iron Oxide Nanofluid

The analytical characterization of thermophysical properties of metal oxide nanofluid has got significant attention in thermal industries due to their high capability of reducing energy loss and enhancing the efficiency of machinery parts. The fascinating heat transfer characteristics of green modulated iron oxide nanoparticles (IONPs) attain significant importance due to their wide range of diverse applications in different industries. In the current study, IONPs were successfully synthesized using an aqueous extract of Aloe vera (Aloe barbadensis) leaves to evaluate its effective thermophysical properties in base fluid like water. The average particle size of 11nm IONPs with its nanofluid of various volume concentrations 0.01 to 0.05 with a different temperature range of 30°C to 50°C shows an enhancement in thermal conductivity of 34.08% compared to distilled water (base fluid). Different characterization technique like Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transforms infrared (FTIR) spectroscopy, UV-visible spectroscopy, and particle size analyzer has been employed to get characteristic modification and formation of iron oxide nanoparticles. The experimentally measured values of thermal conductivity were compared with existing theoretical models for effective enhancement in thermophysical properties and the same was analyzed with the importance of green technique.

Impact of differential quantity of iron oxide nanoparticles incorporated feed on growth, biochemical and haematological characteristics of Mrigal Cirrhinus mrigala

The present study deals with the impact of differential quantity of iron oxide nanoparticles incorporated feed on the growth, biochemical and haematological characteristics of Mrigal. Iron oxide nanoparticles were synthesised and characterized by using 5 UV-Vis spectroscopy(UV-Vis ) , Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDAX), X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR) andVibrating Sample Magnetometer (VSM). Six experimental feeds were prepared by using a fish meal, groundnut oil cake, wheat flour, tapioca flour and differential quantities of iron oxide nanoparticles such as 0, 10, 20, 30, 40, and 50 mg/100g. Feed utilization, biochemical and haematological characteristics of Mrigal were estimated after 21 days. UV-VIS Image spectra show that iron oxide nanoparticles were measured at a wavelength of “328 nm”. SEM image shows the morphological formation of iron oxide nanoparticles and was observed at the wavelength of 1μm.EDAX spectrum recorded on the iron oxide nanoparticles is shown as two peaks located between 0.2KeV and 6.4KeV. XRD results were obtained for the crystal nature of iron oxide nanoparticles and the average size is 20 nm. FT-IR spectrum of iron oxide nanoparticles was analyzed in the range from 4000-500 cm-1.VSM results revealed that saturation magnetization (MS) is 1.019 emu/gm present in iron oxide nanoparticles. The feed consumption, feed conversion efficiency, growth, and relative growth rate of Mrigal were higher in Ex. Feed III. The gross and net growth efficiency of Mrigal were higher in Ex. Feed I. All the blood parameters were gradually increased from Feed I to VI. The total protein, carbohydrate and lipids of Mrigal’s muscle, gill and liver of Mrigal is higher in Feed VI containing 50mg of iron oxide nanoparticles.

A versatile chemical vapor synthesis reactor for in situ x-ray scattering and spectroscopy.

We describe a versatile reactor system for chemical vapor synthesis of nanoparticles, which enables in situ investigations of high temperature gas phase particle formation and transformation processes by x-ray scattering and x-ray absorption spectroscopy. The system employs an inductively heated hot wall reactor as the energy source to start nanoparticle formation from a mixture of precursor vapor and oxygen. By use of a modular set of susceptor segments, it is especially possible to change solely the residence time of the gas mixture while keeping all other process parameters (temperature, gas flow, pressure) constant. Corresponding time-temperature profiles are supported by computational fluid dynamics simulations. The operation of the system is demonstrated for two example studies: tin oxide nanoparticle formation studied by small angle x-ray scattering and iron oxide nanoparticle formation by x-ray absorption spectroscopy.

Attempts to obtain BaTiO3/Fe2O3 core-shell type structures: The role of iron oxide nanoparticle formation and agglomeration

• Magnetometric studies of the BaTiO 3 /Fe 2 O 3 samples prepared using five different chemical routes were done. • Decoration of BaTiO 3 grains with hematite nanoparticles was observed instead.of a well defined core-shell structure. • Tendency of the iron-oxide nanoparticles to form agglomerates reduces the possibility of a continuous shell formation around the core. • Magnetic properties of these composites are dominated by the properties of fine iron-oxide nanopowder. The manuscript shows the studies of structural and magnetic properties of BaTiO 3 /Fe 2 O 3 samples prepared using five different chemical routes. We show that the undertaken processes leaded to the decoration of BaTiO 3 grains with hematite nanoparticles, but not to a creation of a well-defined core-shell structure. These studies revealed that a strong tendency of the iron-oxide nanoparticles to form agglomerates, significantly reduces the possibility of a continuous shell formation around the core, and at the same time it promotes inter-particle interactions between magnetic nanoparticles. A detailed analysis of the results obtained in the structural and magnetic studies, allowed to state that magnetic properties of these composites are dominated by the properties of fine iron-oxide nanopowder. The collected isothermal magnetization curves clearly indicate the canted antiferromagnetic properties characteristic for hematite, while the ac magnetization results exhibit the collective freezing process to the cluster glass like state (characteristic for interacting system of magnetic nanoparticles). This work provides detailed studies of systems prepared under different conditions and methods, which can serve as an important step towards obtaining well defined BaTiO 3 /Fe 2 O 3 core-shell structures.

Echinochloa frumentacea grains extract mediated synthesis and characterization of iron oxide nanoparticles: A greener nano drug for potential biomedical applications

Iron oxide nanoparticles have been used in diverse fields due to their significant applications. The synthesis of iron oxide nanoparticles using plant material extract is a simple, inexpensive and eco-friendly approach. The present study demonstrates the effective bio-synthesis of iron oxide nanoparticles using grains extract of Echinochloa frumentacea. GC-MS analysis report revealed the information about the phytochemicals in aqueous grains extract. The formation of iron oxide nanoparticles was confirmed using UV–visible, XRD, FTIR, HRTEM, EDX, and mapping analyses. The UV–visible spectrum of iron oxide nanoparticles showed the SPR band at 289 nm. The XRD studies confirmed the formation of high crystalline iron oxide nanoparticles. HRTEM analysis showed that the formed nanoparticles were rectangular and triangular in shape and the size ranged between 20 and 40 nm. The iron oxide nanoparticles revealed significant antibacterial activity against the microbes such as Staphylococcus aureus and Salmonella typhi at 150 μg/mL and morphological changes were observed. The high concentration of nanoparticles exhibited 24 and 27 mm zone of inhibition on S. typhi and S. aureus, respectively. We observed the role of biological activities such as antioxidant, anti-inflammatory, and anti-diabetic properties of nanoparticles, and they showed excellent bioactive properties even at a low IC50 value. The antioxidant, anti-inflammatory and anti-diabetic analyses showed high activity at 95.10, 92.10 and 91.68% for 80 μg/mL concentration, respectively. Moreover, the iron oxide nanoparticles exhibited high cytotoxicity (94.36%) against A549 cancer cells and no toxicity against HEK293 normal cells which showed the biocompatibility of nanoparticles. The larvicidal and insecticidal activities of nanoparticles showed the maximum mortality at 48 h in 100 ppm and 72 h in 75, 100 μg/kg, respectively. The morphological and structural changes in larvae and insects validated the effective biological activities of iron oxide nanoparticles. The plant growth study results recommended that the lower concentration of nanoparticles at 60 ppm was helpful for the germination of seeds and growth of root and stem in the Vigna unguiculata plant. Finally, the study results suggested that the synthesized iron oxide nanoparticles can potentially be useful in pharmaceutical, agricultural, targeted drug delivery and biomedical applications.

GREEN SYNTHESIS OF IRON-OXIDE NANOPARTICLES USING SCRAP IRON AS PRECURSOR FOR THE REMOVAL OF PB (II) FROM AQUEOUS MEDIUM

In the present study, low-cost, environmentally friendly, single-step, high productive novel Iron-oxide nanoparticles (NPs) were prepared from scrap iron using a green synthesis method to remove Pb (II) from aqueous solution. The characterization of synthesized nanoparticles was conducted by UV-vis spectroscopy. The crystalline structure and the phase change were clarified by XRD. FE-SEM was done to know the morphology of iron oxide nanoparticles, and the average surface area of 46.856 m2/g was found by the BET surface area analyzer. The XRD plot shows that the obtained magnetite Fe3O4 combines FeO and Fe2O3 as the synthesis was conducted in the open atmosphere. The SEM images confirm the formation of iron oxide nanoparticles with a size of 31 nm. The removal efficiency of the adsorbent was carried out by optimizing the different operational parameters like pH, time, adsorbent dosage, initial concentration of metal ion, contact time by batch studies. The obtained pHzpc (pH 5.7) value indicates that the adsorption process will be favorable at higher pH. The maximum removal efficiency and uptake capacity of lead were 98% and 68.07 mg/g, respectively. Adsorption data obtained were analyzed with Langmuir and Freundlich isotherm equations. The equilibrium data are fitted by Langmuir isotherm in a superior way than that of Freundlich isotherm. The results show that homogeneous adsorption of the metal ion favors heterogeneous adsorption. The maximum adsorption capacity of iron oxide NPs was calculated through Langmuir isotherm was Qmax (68.07) mg/g. Moreover, the adsorption of metal ions with time was also analyzed with the pseudo 1st and pseudo 2nd kinetic equations. The kinetic data are fitted more in the pseudo 2nd order reaction. Adsorption capacity calculated through pseudo 2nd order equation was qe (51.81) mg/g. This literature verifies that NPs synthesized from scrap iron as precursors prove to be an attractive option for removing heavy metals.

Formation of Iron Oxide Nanoparticles in the Internal Cavity of Ferritin-Like Dps Protein: Studies by Anomalous X-Ray Scattering

DNA-binding protein from starved cells (Dps) takes a special place among dodecamer mini-ferritins. Its most important function is protection of bacterial genome from various types of destructive external factors via in cellulo Dps–DNA co-crystallization. This protective response results in the emergence of bacterial resistance to antibiotics and other drugs. The protective properties of Dps have attracted a significant attention of researchers. However, Dps has another equally important functional role. Being a ferritin-like protein, Dps acts as an iron depot and protects bacterial cells from the oxidative damage initiated by the excess of iron. Here we investigated formation of iron oxide nanoparticles in the internal cavity of the Dps dodecamer. We used anomalous small-angle X-ray scattering as the main research technique, which allows to examine the structure of metal-containing biological macromolecules and to analyze the size distribution of metal nanoparticles formed in them. The contributions of protein and metal components to total scattering were distinguished by varying the energy of the incident X-ray radiation near the edge of the metal atom absorption band (the K-band for iron). We examined Dps specimens containing 50, 500, and 2000 iron atoms per protein dodecamer. Analysis of the particle size distribution showed that, depending on the iron content in the solution, the size of the nanoparticles formed inside the protein molecule was 2 to 4 nm and the growth of metal nanoparticles was limited by the size of the protein inner cavity. We also found some amount of iron ions in the Dps surface layer. This layer is very important for the protein to perform its protective functions, since the surface-located N-terminal domains determine the nature of interactions between Dps and DNA. In general, the results obtained in this work can be useful for the next step in studying the Dps phenomenon, as well as in creating biocompatible and solution-stabilized metal nanoparticles.

Investigation of antioxidant and antibacterial activity of iron oxide nanoparticles (IONPS) synthesized from the aqueous extract of Penicillium spp.

The biological synthesis of metal nanoparticles has arisen vastly with significant health and medical applications in recent years. The current study employs Penicillium spp. that was isolated from soils to synthesis iron oxide nanoparticles (IONPs). The antimicrobial and antioxidant activity of the IONPs were investigated. The IONPs were synthesized via the extracellular method using cell-free filtrate and challenged with FeCl3. The characterization of IONPs was performed using UV-spectrophotometer, FTIR, TEM, SEM, EDX, and Zeta Potential Analysis. The antibacterial and antioxidant activity was examined through the disk diffusion method and DPPH-scavenging activity, respectively. This study showed that the IONPs were successfully synthesized from the fungal filtrate of Penicillium spp. The UV-spectrophotometer displayed a peak at 350 ​nm, indicating the formation of IONPs. The spherical shape of IONPs was determined by TEM and SEM analysis, with the size ranging from 3.31 to 10.69 ​nm. The FTIR spectrum of IONPs showed bands at 3313 ​cm−1, and 1636 ​cm−1 revealed the protein's involvement in the formation and capping of nanoparticles. The EDX showed the presence of iron elements in the biosynthesized IONPs, and Zeta potential analysis indicated the high stability of IONPs (+33.9 ​mV). Biosynthesized IONPs exhibited good antibacterial activity against pathogenic bacteria as well as showed potent antioxidant activity. At the highest concentration (250 ​μg), the IONPs showed higher inhibition activity against S. aureus (12 ​± ​0.6 ​nm), E.coli (11.3 ​± ​1.2 ​nm), K.pneumonia (11.3 ​± ​0.6 ​nm), S.sonnie (11.3 ​± ​0.6 ​nm), and P.aeruginosa (11.3 ​± ​0.6 ​nm). IONPs also exhibited antioxidant potential against DPPH radical compared with ascorbic acid with IC50 values of 12.2 ​μg/mL. In conclusion, the biosynthesized IONPs from Penicillium spp. demonstrated the potential biomedical application such as antimicrobial and anticancer agents in the future.

In situ liquid transmission electron microscopy reveals self-assembly-driven nucleation in radiolytic synthesis of iron oxide nanoparticles in organic media.

We have investigated the early stages of the formation of iron oxide nanoparticles from iron stearate precursors in the presence of sodium stearate in an organic solvent by in situ liquid phase transmission electron microscopy (IL-TEM). Before nucleation, we have evidenced the spontaneous formation of vesicular assemblies made of iron polycation-based precursors sandwiched between stearate layers. Nucleation of iron oxide nanoparticles occurs within the walls of the vesicles, which subsequently collapse upon the consumption of the iron precursors and the growth of the nanoparticles. We then evidenced that fine control of the electron dose, and therefore of the local concentration of reactive iron species in the vicinity of the nuclei, enables controlling crystal growth and selecting the morphology of the resulting iron oxide nanoparticles. Such a direct observation of the nucleation process templated by vesicular assemblies in a hydrophobic organic solvent sheds new light on the formation process of metal oxide nanoparticles and therefore opens ways for the synthesis of inorganic colloidal systems with tunable shape and size.