Iron Oxide Research Articles

Iron Oxide Clusters as Electron Donors Under Light Enhance Oxygen Reduction Kinetics at Atomically Dispersed Fe for Photocatalytic CH4 Partial Oxidation

Iron Oxide Clusters as Electron Donors Under Light Enhance Oxygen Reduction Kinetics at Atomically Dispersed Fe for Photocatalytic CH4 Partial Oxidation

Green synthesized iron oxide nanoparticles as a potential regulator of callus growth, plant physiology, antioxidative and microbial contamination in Oryza sativa L.

In tissue culture, efficient nutrient availability and effective control of callus contamination are crucial for successful plantlet regeneration. This study was aimed to enhance callogenesis, callus regeneration, control callus contamination, and substitute iron (Fe) source with FeO-NPs in Murashige and Skoog (MS) media. Nanogreen iron oxide (FeO-NPs) were synthesized and well characterized with sizes ranging from 2 to 7.5 nm. FeO-NPs as a supplement in MS media at 15 ppm, significantly controlled callus contamination by (80%). Results indicated that FeCl3-based FeO-NPs induced fast callus induction (72%) and regeneration (43%), in contrast FeSO4-based FeO-NPs resulted in increased callus weight (516%), diameter (300%), number of shoots (200%), and roots (114%). Modified media with FeO-NPs as the Fe source induced fast callogenesis and regeneration compared to normal MS media. FeO-NPs, when applied foliar spray, increased Plant fresh biomass by 133% and spike weight by 350%. Plant height increased by 54% and 33%, the number of spikes by 50% and 265%, and Chlorophyll content by 51% and 34% in IRRI-6 and Kissan Basmati, respectively. Additionally, APX (Ascorbate peroxidase), SOD (Superoxide dismutase), POD (peroxidase), and CAT (catalase) increased in IRRI-6 by 27%, 29%, 283%, 62%, while in Kissan Basmati, APX increased by 70%, SOD decreased by 28%, and POD and CAT increased by 89% and 98%, respectively. Finally, FeO-NPs effectively substituted Fe source in MS media, shorten the plant life cycle, and increase chlorophyll content as well as APX, SOD, POD, and CAT activities. This protocol is applicable for tissue culture in other cereal crops as well.

Exploring Topochemical Oxidation Reactions for Reversible Tuning of Thermal Conductivity in Perovskite Fe Oxides.

We present a study on the reversibility of thermal conductivity in iron oxides through topochemical oxygen exchange between brownmillerite (BM) (Ca,Sr)FeO2.5 and perovskite (PV) (Ca,Sr)FeO3.0. By using different oxidation methods, including gas phase (O2/O3), liquid phase (NaOCl in H2O), and solid electrolyte (Y2O3:ZrO2), we demonstrate that the oxidation pathway has a critical influence on the reversibility of the ionic-exchange process. Cyclic oxidation and reduction using O2/O3 or NaOCl lead to an important accumulation of structural defects, undermining the reversibility of thermal conductivity. In the case of wet oxidation, we demonstrate an inherent tendency of negative charge-transfer oxides toward amorphization and elucidate the origin of this effect. Conversely, the electrochemical injection of the O2- ions via a Y2O3:ZrO2 solid electrolyte reduces structural damage significantly, enhancing both reversibility and durability. This study underscores the importance of selecting appropriate topochemical oxygen exchange methods to maintain structural integrity and optimize functional performance in oxide-based tunable devices.

Incorporating iron oxide nanoparticles in polyvinyl alcohol/starch hydrogel membrane with biochar for enhanced slow-release properties of compound fertilizers

Biochar-based fertilizers show promise in enhancing nutrient utilization and soil health, but their slow-release performance remains a challenge. Herein, hydrogel membranes incorporating iron oxide nanoparticles within a polyvinyl alcohol and starch matrix (Fe/PVA/ST) were synthesized. These membranes were utilized to coat compound fertilizer particles, with biochar powder applied to the outer layer to form what is known as Fe/PVA/ST-BSRFs. The results revealed that Fe/PVA/ST-BSRFs exhibit markedly improved slow-release performance compared to both PVA/ST-BSRFs lacking iron nanoparticles and commercial compound fertilizers. Within a 30-day period, the cumulative leaching ratios of N, P, and K from Fe/PVA/ST-BSRFs with 0.75 % iron content were significantly lower compared to other tested fertilizers, with values of 22.87 %, 34.93 %, and 84.08 %, respectively. Furthermore, the incorporation of iron oxide nanoparticles into the PVA/ST membrane enhanced its swelling and water-retention properties without compromising its biodegradability. Mechanistic investigations revealed that the exceptional slow-release properties of Fe/PVA/ST-BSRFs stem from a combination of nutrient diffusion control outside the membrane and the loose control mechanism of the membrane. Pot tests demonstrated that Fe/PVA/ST-BSRFs effectively promoted the growth of chili plants while ensuring high utilization of N-P-K and improving the nutritional indices of chili fruits. Economic analysis further underscored the promising application prospects of Fe/PVA/ST-BSRFs.

Biosynthesis of Iron Oxide Nanoparticles by Marine Streptomyces sp. SMGL39 with Antibiofilm Activity: In Vitro and In Silico Study

One of the major global health threats in the present era is antibiotic resistance. Biosynthesized iron oxide nanoparticles (FeNPs) can combat microbial infections and can be synthesized without harmful chemicals. In the present investigation, 16S rRNA gene sequencing was used to discover Streptomyces sp. SMGL39, an actinomycete isolate utilized to reduce ferrous sulfate heptahydrate (FeSO4.7H2O) to biosynthesize FeNPs, which were then characterized using UV–Vis, XRD, FTIR, and TEM analyses. Furthermore, in our current study, the biosynthesized FeNPs were tested for antimicrobial and antibiofilm characteristics against different Gram-negative, Gram-positive, and fungal strains. Additionally, our work examines the biosynthesized FeNPs’ molecular docking and binding affinity to key enzymes, which contributed to bacterial infection cooperation via quorum sensing (QS) processes. A bright yellow to dark brown color shift indicated the production of FeNPs, which have polydispersed forms with particle sizes ranging from 80 to 180 nm and UV absorbance ranging from 220 to 280 nm. Biosynthesized FeNPs from actinobacteria significantly reduced the microbial growth of Fusarium oxysporum and L. monocytogenes, while they showed weak antimicrobial activity against P. aeruginosa and no activity against E. coli, MRSA, or Aspergillus niger. On the other hand, biosynthesized FeNPs showed strong antibiofilm activity against P. aeruginosa while showing mild and weak activity against B. subtilis and E. coli, respectively. The collaboration of biosynthesized FeNPs and key enzymes for bacterial infection exhibits hydrophobic and/or hydrogen bonding, according to this research. These results show that actinobacteria-biosynthesized FeNPs prevent biofilm development in bacteria.

Facile synthesis and characterization of magnetic iron oxide (Fe3O4)-loaded cationic amino-modified passion fruit shell nanocomposite and their application in removal of anionic Alizarin Red S dye from aqueous medium

A newly synthesized magnetic nanocomposite, iron oxide-loaded cationic amino-modified passion fruit shell (Fe3O4@CMPFS), was utilized as a sorbent to eliminate anionic Alizarin Red S (ARS) dye from the wastewater. The Fe3O4@CMPFS was characterized to confirm the properties by physicochemical methods such as VSM, XRD, pHPZC, BET, FTIR, and FE-SEM with EDX. Batch tests were conducted to study the adsorption process, focusing on factors like the solution pH (from 2.0 to 11), amount of Fe3O4@CMPFS (from 10 to 80 mg/30 mL), contact duration (from 0 to 240 min), agitation speed (from 0 to 400 rpm) and temperature (from 298 to 328 K). The optimal conditions for attaining a 92.3 % removal efficiency were found to be a pH of 2.0, 60 mg of Fe3O4@CMPFS, a contact time of 60 min, agitation at 250 rpm, and a temperature of 298 K. The Fe3O4@CMPFS was determined to have a pHPZC value of approximately 6.2. The kinetic data indicated that the adsorption of ARS onto Fe3O4@CMPFS followed the pseudo-second-order model (high R2 = 0.9919; low SSE = 1.5) and was governed by film and intraparticle diffusion mechanisms. Furthermore, the isotherm data fit well with the Langmuir model (high R2 = 0.9983; low χ2 = 12.69), suggesting monolayer adsorption behaviour. The maximal sorption uptake of ARS on the Fe3O4@CMPFS was determined to be 233.4 ± 3.174 mg/g at 298 K through the Langmuir model. The estimated ΔH° (18.3 kJ/mol) and ΔS° (82 J/mol K) indicate the endothermic and enhanced randomness at the adsorbent/solute interface. The negative ΔG° values (−6.2298 to −8.7283 kJ/mol at 298–328 K) confirm spontaneous sorption dominated by physisorption. The Fe3O4@CMPFS composite had good recyclability and was easy to separate from water, which maintained excellent adsorption performance after eight regeneration cycles. The superb adsorption efficiency and recycling performance of Fe3O4@CMPFS provide a prospect way to remove ARS dye from industrial effluents.

Nanoremediation of tilapia fish culture using iron oxide nanoparticles biosynthesized by Bacillus subtilis and immobilized in a free-floating macroporous cryogel

Background and aimContamination from increased anthropogenic activities poses a threat to human health as well as the ecosystem. To develop a nanotechnological approach to improve aqua fisheries, we synthesized magnetic hematite nanoparticle-based gel and evaluated its efficacy in a cadmium-polluted closed system to decontaminate water and improve tilapia fish health.MethodsGreen iron oxide nanoparticles were biosynthesized by the metabolite of bacillus subtilis and incorporated into polyvinyl alcohol to construct a hydrogel by cryogelation.Key findingsThe cryogel had interconnected macropores with diameters widely ranging between 20 and 200 μm and could be free-floating in water. When applied in cadmium-polluted tilapia culture, this nanogel reduced turbidity and ammonia in the aquarium, adsorbed cadmium from the water with a larger quantity on the gel’s outer surface than in its center., and reduced cadmium concentration in tilapia’s liver, gills, and muscles. Application of this nano-based cryogel reduced the toxic effects of cadmium on tilapia fish. It maintained hepatic and renal cell nuclear integrity as determined by comet assay. This nano-treatment also reversed the cadmium-induced elevations of plasma lipids, glucose, stress marker cortisol, the hepatic enzymes AST and ALT, and the kidney function marker urea, and improved the lymphocytopenia and other hematological functions in tilapia fish intoxicated by cadmium.

Chiral Nematic Cellulose Nanocrystal Films for Enhanced Charge Separation and Quantum-Confined Stark Effect.

Efficient charge separation is essential in various optoelectronic systems, yet it continues to pose substantial challenges. Building upon the recent evidence that chiral biomolecules can function as electron spin filters, this study aims to extend the application of chirality-driven charge separation from the molecular level to the mesoscale and supramolecular scale. Utilizing cellulose nanocrystals (CNCs) derived from cellulose, the most abundant biomaterial on Earth, this research leverages their self-assembly into chiral nematic structures and their dielectric properties. A device is introduced featuring a chiral nematic hybrid film composed of CNCs and quantum dots (QDs), decorated with iron oxide nanoparticles. Using the quantum-confined Stark effect (QCSE) to probe charge separation, we reveal significant sensitivity to the circular polarization of light and the chiral nematic structure of the film. This approach achieves effective, long-lasting charge separation, both locally and across length scales exceeding 1 μm, enabling potential applications such as self-assembled devices that combine photovoltaic cells with electric capacitance as well as optical electric-field hybrid biosensors.

Effects of Ni Loadings on the Structure and Morphology of Carbon Nanotubes Using Nickel Doped Iron Oxide Catalysts

AbstractIron oxide and their different doped iron oxide catalyst have been used for decades and are considered as efficient catalysts in several synthesis schemes including synthesis of carbon nanotubes. The iron oxide of the catalyst is abundant in nature, high catalytic activity at low over potentials, stability in basic media and low cost, making it environmentally and economically attractive. Nickel doped iron oxide catalyst have not been reported in the literature. Doping of nickel over iron oxide catalyst, different percentage 1 %, 5 %, 10 % and 20 % were done by impregnation method. The samples were characterized by X‐Ray powder Diffraction (XRD), Fourier‐Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Energy Dispersive X‐ray (EDX) and Thermo Gravimetric Analysis (TGA). Nickel doped iron oxide was used as catalyst for the synthesis of carbon nanotubes (CNTs) and doping changed the morphology of carbon nanotube (CNTs). FTIR results confirmed the doping and presence of different functional groups. Chemical vapor deposition (CVD) was carried out for the synthesis of multiwall carbon nanotubes (MWCNTs) on nickel doped iron oxide catalyst for different percentage (1 %, 5 %, 10 % and 20 %) separately. CVD assembly was carried in tube furnace and the reaction was checked at two different temperature i.e 700 °C and 750 °C and using methane and compressed natural gas (CNG) as precursors. The catalyst was activated in the furnace at 800 °C for an hour. Methane and argon were used in proportion 2 : 1 inside the furnace. SEM showed formation of CNTs at 750 °C with CNG precursor. Formation of CNTs increased with increasing doping with this CNTs was confirmed by SEM.

Band Gap Engineering of Spin-Coated <i>α</i>-Fe<sub>2</sub>O<sub>3</sub> for Solar Water Splitting Utilizing a Facile Zinc Doping Route

Iron oxide (hematite, α-Fe2O3) is an earth-abundant material having a favorable band gap for solar energy harvesting by producing Hydrogen (H2) by photoelectrochemical (PEC) water splitting. Although Fe2O3 has a valence band maximum (VBM) more positive than the water oxidation potential in the normalized hydrogen energy scale (NHE), it can not be used as a photocathode because of the more positive conduction band minima (CBM) than the reduction potential of the electrons required for the hydrogen evolution reaction (HER). This paper reports the band gap engineering of Fe2O3 by doping it with Zinc (Zn) through a facile way to modify its CBM and VBM to enable it to work as an ideal and efficient photocatalyst. One-pot synthesis of α-Fe2O3 doped with Zn was achieved by spin-coating a precursor solution prepared with FeCl2 and Zinc acetate (Zn(CH3COO)2.2H2O) on fluorine-doped tin oxide (FTO) or glass substrates. The films were then annealed in air at around 450 °C. The surface morphology and the crystal structure of the Fe2O3 were studied using SEM (Scanning Electron Microscope) and XRD (X-ray diffractometer). The UV-VIS spectrophotometry and spectroelectrochemistry (SEC) determined the band energies of α-Fe2O3 and Zn-doped α-Fe2O3. The band gap and CBM of pristine α-Fe2O3 were found to be -2.09 eV and -5.31 eV vs. EVAC, whereas the band gap and CBM of Zn-doped α-Fe2O3 were -1.96 eV and -4.3 eV vs. EVAC respectively. The outcome of the photoelectrochemical study shows that α-Fe2O3 doped with Zn can have a reduced band gap with more negative CBM than the H+/H2 reduction potential that efficiently ensures both oxygen and hydrogen evolution reaction.

Environmentally friendly, high near-infrared reflection green pigments for thermal insulation

In this paper, TiO2 and MgAl-LDHs were coated on yellow pigment hydroxyl iron oxide (FeOOH) with sol-gel and hydrothermal synthesis method respectively to prepare loaded yellow pigment (FT8M0.25). Then, phthalocyanine blue (CuPc) was combined with FT8M0.25 to prepare composite green pigment (FT8M0.25Px). The results indicate the FT8M0.25Px has the structural characteristics of hydrotalcites and CuPc. The surface of FeOOH pigment has a clear TiO2 coating layer and MgAl-LDHs flake structure. KPFM analysis indicate that there is electron transfer between the interfaces of pigments. According to the analysis of color performance and near-infrared reflectance (NIR), the FT8M0.25P0.13 (a*=-12.98) is greener than that of Cr2O3 (a*=-6.65). The NIR of FT8M0.25P0.13 is as high as 73.54 %. The visible light absorption spectrum characteristics determine the color of the pigments, and there is electron transfer between the interfaces of each group. The formation of multi-level interfaces and the resulting multiple light reflections increase the reflectivity of the pigment. The developed coating achieved a considerable temperature difference of 20 °C before and after the coating surface with excellent photostability and reusability, which makes it possible for pigments to replace chromium containing pigments and be used as energy-saving cold pigments.

Interfacial Acid‐Like Microenvironment and Orbital Modulating Strategy toward Efficient Hydrogen Evolution in Neutral High‐Salinity Wastewater/Seawater

Electrochemical high‐salinity wastewater splitting is a promising technology for green hydrogen (H2) production. However, the kinetics of hydrogen evolution reaction (HER) in neutral media is slow, and the high theoretical potential of oxygen evolution reaction leads to large energy losses. Herein, an iron‐based electrocoagulation‐coupled hydrogen production integrated system (IEHPS) is constructed, which is realized by coupling low‐potential anodic iron oxidation reaction with cathodic HER. The non‐noble metal HxWO3‐Ni catalyst is synthesized by fabricating a proton sponge HxWO3 to achieve an interfacial acid‐like microenvironment and doping it with Ni heteroatom to modulate the 4d orbital of W, thereby weakening the adsorption strength of the W site toward hydrogen. Consequently, the HxWO3 Ni demonstrates remarkable performance characteristics, boasting a mere 131 mV overpotential at 10 mA cm−2 and Tafel slope of 44 mV dec− in neutral media. Operating at an applied voltage of 1.5 V, the IEHPS exhibits a high hydrogen production rate of 235 mL g−1 min−1 in seawater. It achieves nearly complete removal of contaminants like rhodamine B and heavy metal ions within a rapid 8–20 min, with an energy consumption of only 3.7 kWh Nm−3. This study provides a promising pathway for efficient and energy‐saving production of high‐purity hydrogen and effective treatment of high‐salinity wastewater.

Investigation of high-temperature oxide-metal melts during induction melting in a cold crucible

The object of the study is high-temperature oxide-metal melts obtained in furnaces of induction melting in a cold crucible (IMCC). The results of pilot tests in IMCC furnaces at melt temperatures of more than 2200 оC in air, conducted to study the distribution of components between the oxide and metal phases of a two-phase melt with limited miscibility of components, are presented. The results of physicochemical studies of materials obtained by quenching crystallization of a high-temperature melt are presented, confirming the reduction of silicon and the oxidation of iron with the redistribution of these components between the oxide and metal phases. This experimental result contradicts the well-known Ellingham diagrams and thermodynamic calculations, but a similar effect is observed experimentally in the U–O–Fe system. Thus, the IMCC method allows for the inversion of redox processes in a number of oxide-metal systems, which can be used to obtain new materials and create technologies for high-temperature extraction of target components.

Effect of Temperature and Oxygen Concentration on Corrosion of J55 Steel in an O2/CO2 Environment

ABSTRACTThe corrosion product competition and transformation process of J55 under an O2/CO2 environment in the temperature range of 50–350°C and 0–1 MPa oxygen partial pressure range, respectively, were studied using electrochemical and surface analysis techniques as well as thermodynamic calculations to determine its corrosion rate change law and pitting corrosion phenomenon. This study demonstrates that the uniform corrosion rate of J55 with increasing temperature shows a trend of first increasing, then decreasing, and finally increasing. The transformation of its corrosion products, from FeCO3 into Fe3O4, is consistent with the altering corrosion rate law with increasing temperatures. J55 corrodes faster at 350°C as the O2 partial pressure increases. When the O2 partial pressure is low, the predominant kind of corrosion product that is obtained is FeCO3; when the O2 partial pressure exceeds 0.2 MPa, all corrosion products are transformed into iron oxides. As the oxygen partial pressure increases, J55's corrosion product film becomes increasingly less protective of the substrate, making the substance more vulnerable to corrosion reactions.

Corrosion Evaluation and Mechanism Research of AISI 8630 Steel in Offshore Oil and Gas Environments.

In this study, we optimized the traditional composition of AISI 8630 steel and evaluated its corrosion resistance through a series of tests. We conducted corrosion tests in a 3.5% NaCl solution and performed a 720 h fixed-load tensile test in accordance with the NACE TM-0177-2016 standard to assess sulfide stress corrosion cracking (SSCC). To analyze the corrosion products and the structure of the corrosion film, we employed X-ray diffraction and transmission electron microscopy. The corrosion rate, characteristics of the corrosion products, structure of the corrosion film, and corrosion resistance mechanism of the material were investigated. The results indicate that the optimized AISI 8630 material demonstrates excellent corrosion resistance. After 720 h of exposure, the primary corrosion products were identified as chromium oxide, copper sulfide, iron oxide, and iron-nickel sulfide. The corrosion film exhibited a three-layer structure: the innermost layer with a thickness of 200-300 nm contained higher concentrations of alloying elements and formed a dense, cohesive rust layer that hindered the diffusion of oxygen and chloride ions, thus enhancing corrosion resistance. The middle layer was thicker and less rich in alloying elements, while the outer layer, approximately 300-400 nm thick, was relatively loose.

Geochemistry of Mafic Rocks From the Nagrota–Kathindi Section, Himachal Pradesh, Northwestern Himalaya: A Probable Example of Plume–Lithosphere Interaction

ABSTRACTThe Northwest Himalayan region has a record of several phases of mafic magmatic activity spanning from Precambrian to Cenozoic in a dynamic tectonic setting. Here, we studied detailed petrography and new whole‐rock geochemistry of mafic volcanic and dykes from the Nagrota–Kathindi Section (NKS), Himachal region of the NW Himalaya, to understand the petrogenesis and possible tectonic setting. Both rock types have comparable mineralogical compositions (clinopyroxene + plagioclase + actinolite‐tremolite + chlorite + iron oxides ± hornblende ± epidote ± quartz ± carbonates) overprinted by greenschist to lower amphibolite facies metamorphism. The mafic volcanic and dykes of NKS exhibit subalkaline basalts to basaltic andesites and a typical tholeiite compositional character. The chondrite‐normalized rare earth element pattern exhibits similar LREE‐enrichment and strong HREE‐fractionation, whereas primitive mantle‐normalized multi‐element patterns show pronounced LILE‐enrichment of Rb, Ba, Th, LREE, and HFSE depletion of Nb, K, P, and Ti. The Zr–Y–Nb–Th relationships indicate that both rock types were derived from the plume source, whereas low Nb/La (< 1), similar high large‐ion lithophile element concentrations, and pronounced negative Nb, Zr, P, and Ti anomalies suggest that components other than mantle plume must have been involved in the generation and evolution of both rock types, that is, most likely plume and subcontinental lithosphere mantle (SCLM) interaction. The genesis of parent magma for the NKS volcanic and dykes was derived by 4%–6% and 10%–20% partial melting from the spinel + garnet lherzolite stability field. The majority of the studied samples correspond to spinel + garnet peridotite melting on (Gd/Yb)N versus CaO/Al2O3 diagram, thereby corroborating residual garnet in the mantle restite. All the basalts and dykes from the NK section did erupt/intrude in an intracontinental rift setting based on geochemical discrimination. The key petro‐tectonic processes attributed to the formation of these rocks are as follows: (i) the melting of the ascending plume by adiabatic decompression; (ii) the partial melting of this plume–SCLM source in the melting regime, which produces basaltic magma with a tholeiitic composition; and (iii) the release of heat that provides the thermal condition for melting of SCLM and interaction between upwelling mantle plume and subduction metasomatized SCLM.

Unlocking High Capacity and Reversible Alkaline Iron Redox Using Silicate-Sodium Hydroxide Hybrid Electrolytes.

Alkaline iron (Fe) batteries are attractive due to the high abundance, low cost, and multiple valent states of Fe but show limited columbic efficiency and storage capacity when forming electrochemically inert Fe3O4 on discharging and parasitic H2 on charging. Herein, sodium silicate is found to promote Fe(OH)2/FeOOH against Fe(OH)2/Fe3O4 conversions. Electrochemical experiments, operando X-ray characterization, and atomistic simulations reveal that improved Fe(OH)2/FeOOH conversion originates from (i) strong interaction between sodium silicate and iron oxide and (ii) silicate-induced strengthening of hydrogen-bond networks in electrolytes that inhibits water transport. Furthermore, the silicate additive suppresses hydrogen evolution by impairing energetics of water dissociation and hydroxyl de-sorption on iron surfaces. This new silicate-assisted redox chemistry mitigates H2 and Fe3O4 formation, improving storage capacity (199 mAh g-1 in half-cells) and coulombic efficiency (94 % after 400 full-cell cycles), paving a path to realizing green battery systems built from earth-abundant materials.

A Novel Superparamagnetic-Responsive Hydrogel Facilitates Disc Regeneration by Orchestrating Cell Recruitment, Proliferation, and Differentiation within Hostile Inflammatory Niche.

In situ disc regeneration is a meticulously orchestrated process, which involves cell recruitment, proliferation and differentiation within a local inflammatory niche. Thus far, it remains a challenge to establish a multi-staged regulatory framework for coordinating these cellular events, therefore leading to unsatisfactory outcome. This study constructs a super paramagnetically-responsive cellular gel, incorporating superparamagnetic iron oxide nanoparticles (SPIONs) and aptamer-modified palladium-hydrogen nanozymes (PdH-Apt) into a double-network polyacrylamide/hyaluronic acid (PAAm/HA) hydrogel. The Aptamer DB67 within magnetic hydrogel (Mag-gel) showed a high affinity for disialoganglioside (GD2), a specific membrane ligand of nucleus pulposus stem cells (NPSCs), to precisely recruit them to the injury site. The Mag-gel exhibits remarkable sensitivity to a magnetic field (MF), which exerts tunable micro/nano-scale forces on recruited NPSCs and triggers cytoskeletal remodeling, consequently boosting cell expansion in the early stage. By altering the parameters of MF, the mechanical cues within the hydrogel facilitates differentiation of NPSCs into nucleus pulposus cells to restore disc structure in the later stage. Furthermore, the PdH nanozymes within the Mag-gel mitigate the harsh inflammatory microenvironment, favoring cell survival and disc regeneration. This study presents a remote and multi-staged strategy for chronologically regulating endogenous stem cell fate, supporting disc regeneration without invasive procedures.

Effect of different metallic doping elements on the physical properties of iron oxide thin films

This study investigates the physical properties of pure and Co, Cr, Mn, and Ni-doped Fe2O3 thin films fabricated using spray pyrolysis techniques on glass substrates. The primary aim is to understand how doping influences the structural, optical, and dielectric properties of Fe2O3 thin films. The deposition parameters were kept constant for all samples, with a fixed dopant concentration of 3 weight percent (wt%). X-ray diffraction (XRD) analysis revealed a single diffraction peak indexed as (104), decreasing in crystallite size from 17.27 nm for the pure film to approximately 11.5 nm for all doped films. Field emission scanning electron microscopy (FE-SEM) images displayed non-homogeneous grain formation, characterized by an average grain size larger than the crystallite size, indicating agglomeration. The optical band gap value shifted from 2.54 eV for the pure film to higher values upon doping with various elements, signifying direct allowed transitions. Changes in refractive index dispersion with wavelength were observed based on the dopant type. The application of the Spitzer-Fan model revealed an increase in high-frequency dielectric constant upon doping compared to the pure film, varying across different dopants. Photoluminescence (PL) spectra recorded under excitation at 340 nm exhibited multiple emission peaks within the spectral range of 399 to 600 nm.

A Review on Nanoparticles : The Building Blocks of Tomorrows Technology

Nanoparticles, defined as particles with dimensions in the nanometer range, exhibit unique properties that differ from their bulk counterparts, making them invaluable across various fields such as medicine, electronics, and environmental protection. Their small size and specific characteristics enable advanced applications, including targeted drug delivery, enhanced imaging, and improved sensors. Notable types of nanoparticles include silver, gold, magnetic, iron oxide, and platinum, each with distinct uses: silver for antimicrobial applications, gold for protein detection and drug delivery, magnetic for drug delivery and bio sensing, iron oxide for diagnostics and therapy, and platinum for catalysis. Nanoparticles are synthesized through top-down methods like milling and laser ablation, and bottom-up approaches such as sol-gel and hydrothermal processes. Their preparation involves techniques like emulsion-solvent evaporation and polymerization. Effective characterization, including analysis of size, shape, zeta potential, and drug entrapment efficiency, is essential for optimizing their performance in various applications. The review's current focus is on the synthesis, types, characterization, and most advanced applications of nanotechnology.