Non-photocatalytic electricity generation and thermoluminescence in natural hematite: Application in hydroelectric cell and dosimeter

Environmentally friendly hydroelectric power cells (HEC) and thermoluminescence dosimeters (TL) were manufactured using natural hematite. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) studies confirmed multimodal particle size range of 30-90 nm for natural hematite. Brunauer-Emmett-Teller (BET) analysis confirmed mesoporous and nanoporous structure with average pore size of 30 nm. X-ray Photoelectron Spectroscopy, photoluminescence, ultraviolet-visible spectral analyses confirmed the presence of oxygen vacancies on the surface of hematite. Surface area of natural hematite was considerable (33.48 m2/g), band gap was small (1.7 eV), and porosity was high (31%). A square hematite hydroelectric power cell with an area of 4.84 cm2 generated electricity by redox reaction and produced an open circuit voltage of 0.98 V, a stable short circuit current of 7.0 mA, and open circuit power of 6.86 mW. The TL annealing curve is recorded using a hematite sample annealed at different temperatures (100 °C-700 °C) and irradiated with a60Co gamma source with different radiation doses (100 Gy, 15 kGy). Deconvolution analysis of the TL glow curve reveals a prominent single emission band at 178 °C and high linearity in the dose range from 2 kGy to 9 kGy for sample annealed at 400 °C. Oxygen vacancies, which function as luminous traps, are thought to be the cause of the cause of the observed behaviour. Chen's peak method and initial rise method are used to calculate trapping factors such as activation energy, frequency factor and order of kinetics.

A novel water-soluble polymer nanocomposite containing ultra-small Fe3O4 nanoparticles with strong antibacterial and antibiofilm activity

A novel water-soluble polymer nanocomposite containing ultra-small iron oxide nanoparticles, intercalated into a biocompatible matrix of 1-vinyl-1,2,4-triazole and N-vinylpyrrolidone copolymer has been synthesized for the first time. The use of an original polymer matrix ensured effective stabilization of the crystalline phase of iron oxides at an early stage of its formation in an ultra-small (2-8 nm, average diameter is 4.8 nm) nanosized state due to its effective interaction with the functional groups of copolymer macromolecules. At the same time, the copolymer ensures the long-term stability of iron oxide nanoparticles in a nanosized dispersion. The structure and physicochemical properties of the copolymer and nanocomposite were studied by elemental analysis, 1H and 13C NMR spectroscopy, gel permeation chromatography, Fourier-transform infrared spectroscopy, transmission and scanning electron microscopy, dynamic light scattering, thermogravimetric analysis and differential scanning calorimetry. The nanocomposite exhibits high antibacterial and antibiofilm activity against both Gram-negative and Gram-positive bacteria. The nanocomposite at a concentration of 500 and 1000 μg mL-1 leads to complete death of Escherichia coli cells after 24 and 3 hours of incubation, respectively. The nanocomposite at a concentration of 100 μg mL-1 leads to complete death of Staphylococcus aureus cells after 24 hours of incubation. Which indicates the potential of using the nanocomposite for the treatment of superficial wounds and purulent-inflammatory complications.

Effect of low temperature calcination on micro structure of hematite nanoparticles synthesized from waste iron source

Hematite (α-Fe2O3) nanoparticles have been synthesized from waste source of iron which contains a prominent amount of iron (93.2 %) and investigated the effect of low temperature calcination. The two-step synthesis method involved preparing ferrous sulfate through acid leaching process followed by oxidation and calcination at temperatures ranging from 200 to 400 °C to produce the desired α-Fe2O3 in nano form. The structure, size and morphology of the hematite nanoparticles were characterized using various instrumental techniques including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Fourier transformed infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-visible diffuse reflectance spectroscopy (DRS), and a nanoparticle size analyzer. Hematite single phase was confirmed by XRD and the phase occurred at 200 °C might indicate the stability range of hematite under certain condition. The average crystal sizes were determined using Debye Scherer formula, modified Scherer formula, size strain plot equation and Halder-Wagner-Langford's method and the results show that crystallite sizes decreased with increasing calcination temperature. XPS analysis confirmed the chemical state (Fe3+) and surface chemistry of the hematite nanoparticles calcined at 300 °C. Raman spectrum also supported that the nanoparticles were complete hematite phase and the intensity of all the features decreased with increasing calcination temperature which are consistence with the result obtained from XRD pattern. FTIR spectra of the samples also confirms the XRD results. Morphological analysis obtained from SEM and TEM images suggested the agglomerated irregular spherical nanoparticles with grain size 13.49 nm calcined at 300 °C. Band gap energy of the samples were calculated from DRS data and the values ranging from 2.30 to 2.42 eV which are slightly higher than the bulk (∼2.1eV). Particles size analysis have been carried out using DLS and Z-average particle size and poly dispersity index (PDI) were measured which indicate the particles are nearly same size (220-226 nm).

Green-synthesized α-Fe2O3-nanoparticles as potent antibacterial, anti-biofilm and anti-virulence agent against pathogenic bacteria

BACKGROUND

Antimicrobial resistance (AMR) presents a serious threat to health, highlighting the urgent need for more effective antimicrobial agents with innovative mechanisms of action. Nanotechnology offers promising solutions by enabling the creation of nanoparticles (NPs) with antibacterial properties. This study aimed to explore the antibacterial, anti-biofilm, and anti-virulence effects of eco-friendly synthesized α-Fe₂O₃ nanoparticles (α-Fe₂O₃-NPs) against pathogenic bacteria.

METHODS

The α-Fe2O3-NPs were synthesized using a green synthesis method that involved Bacillus sp. GMS10, with iron sulfate as a precursor. The NPs were characterized through ultraviolet-visible (UV-Vis) spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray Spectroscopy (EDX), Dynamic Light Scattering (DLS), Zeta Potential Analysis, X-ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FT-IR). Their antimicrobial activity was assessed against Gram-positive and Gram-negative bacteria. The study also evaluated the effect of the α-Fe2O3-NPs on bacterial cell membrane disruption, biofilm formation, efflux pump inhibition, and swarming motility.

RESULTS

The UV-Visible spectrum showed a peak at 228 nm, indicating plasmon absorbance of the α-Fe2O3-NPs. FESEM revealed spherical NPs (~ 30 nm), and DLS confirmed a hydrodynamic size of 36.3 nm with a zeta potential of -25.1 mV, indicating good stability. XRD identified the rhombohedral α-Fe2O3 phase, and FTIR detected O-H, C-H, C = O, and Fe-O functional groups, suggesting organic capping for stability. Antibacterial assays demonstrated that the α-Fe2O3-NPs had MIC values ranging from 0.625 to 5 µg/mL and MBC values between 5 and 20 µg/mL, with a strong effect against Gram-positive bacteria. The NPs significantly increased membrane permeability, inhibited biofilm formation in S. aureus and E. coli, and disrupted efflux pumps in S. aureus SA-1199B (a fluoroquinolone-resistant strain overexpressing norA). Additionally, the α-Fe2O3-NPs inhibited P. aeruginosa swarming motility.

CONCLUSION

The bacteria-synthesized α-Fe2O3-NPs demonstrated significant antimicrobial activity, particularly against Gram-positive bacteria, and exhibited strong potential for inhibiting biofilm formation and efflux pump activity, offering a promising strategy to address AMR. Focus on further evaluating their therapeutic potential in clinical settings and conducting comprehensive assessments of their safety profiles to ensure their applicability in medical treatments.

CLINICAL TRIAL NUMBER

Not applicable.

Reviewing arsenic biomineralization: An upcoming strategy for mining wastewater treatment

Human activities are the main cause of arsenic contamination in the environment and water resources, being the mining industry an important source of arsenic contamination because this element is released into the environment in solid, liquid, and gaseous wastes. Currently, several physical and chemical processes could be used for the removal of arsenic in water, but these alternatives depend on the concentration of arsenic. At low concentrations (nanograms or micrograms per liter) arsenic can be removed by membrane technologies. When arsenic is at high concentrations (milligrams or grams per liter), treatment options are reduced to inefficient processes of high economic cost and poor chemical stability of the precipitate, returning consequently arsenic into the environment. Biomineralization is a biological process where microorganisms induce the formation of minerals. This bioprocess has gained interest in recent years for the removal of contaminants from liquid effluents. This review details the harmful effects of arsenic on the health and exposes the relevance of arsenic contamination related to mining activity, whose effluents contain high concentration of arsenic. It also describes and analyzes advances in arsenic treatment strategies through biomineralization using microorganisms, such as sulfate-reducing bacteria, iron- and manganese-oxidizing microorganisms, and ureolytic microorganisms, detailing aspects of effectiveness, applicability, chemical stability of biominerals and future perspectives in their industrial application. To our knowledge, there are no previous reports compiling, analyzing, and explaining in detail the biomineralization of arsenic as a single element. The importance of this review is to deliver in a summarized and systematized way the main aspects and perspectives on the application of microorganisms to remove toxic elements, such as arsenic, from effluents.

Investigation of Far Infrared Emission and UV Protection Properties of Polypropylene Composites Embedded with Candlenut-Derived Biochar for Health Textiles

Far infrared radiation (FIR) within the wavelength range of 4-14 μm can offer human health benefits, such as improving blood flow. Therefore, additives that emit far infrared radiation have the potential to be incorporated into polymer/fabric matrices to develop textiles that could promote health. In this study, biochar derived from candlenuts and pyrolyzed with activated carbon (AC) was incorporated into polypropylene (PP) films and investigated for its potential as a health-promoting textile additive. The properties of biochar were compared with other far infrared (FIR) emitting additives such as hematite, Indian red ochre, and graphene. The addition of biochar increased FIR emissivity to 0.90, which is 9% higher than that of pristine PP. Additionally, biochar enhanced UV and near-infrared (NIR) blocking capabilities, achieving an ultra-protection factor (UPF) of 91.41 and NIR shielding of 95.85%. Incorporating 2 wt% biochar resulted in a 3.3-fold higher temperature increase compared to pristine PP after 30 s of exposure to an FIR source, demonstrating improved heat retention. Furthermore, the ability to achieve the lowest thermal effusivity among other additives supports the potential use of biochar-incorporated fabric as a warming material in cold climates. The tensile properties of PP films with biochar were superior to those with other additives, potentially contributing to a longer product lifespan. Additionally, samples with red ochre exhibited the highest FIR emissivity, while samples with hematite showed the highest capacity for UV shielding.

Anticancer efficacy of magnetite nanoparticles synthesized using aqueous extract of brown seaweed Rosenvingea intricata, South Andaman, India

Cancer is a global issue and hence various efforts are being made. Iron oxide is considered a significant biochemical agent in the biomedical arena for cancer treatment. Marine macroalgae-mediated iron oxides especially, magnetite (Fe3O4) nanoparticles (NPs) are a prospective alternative to diagnose and treat cancer owing to their fluorescent and magnetic properties. We intend to appraise the usability of the aqueous extract of Rosenvingea intricata (R. intricata) in Fe3O4 NPs synthesis and to study their cytotoxic effects against human hepatocarcinoma (Hep3B) and pancreatic (PANC1) cancer cells. In the present study, R. intricata were collected from the coastal region of South Andaman, India. Aqueous extracts of R. intricata were utilized to synthesize Fe3O4 NPs via the co-precipitation method. Phycosynthesized Fe3O4 NPs exhibited wide peak at 400-600 nm from ultraviolet-visible diffused reflectance spectroscopic analysis which validated the formation of NPs. Band edge emission peak at 660 nm in fluorescent spectra confirmed the quantum confinement in Fe3O4 NPs. Fourier transform infrared spectroscopy confirmed the role of R. intricata as a capping and reducing agent with functional groups such as O-H, C-H, C=O, N=O, C=C, C-O, C-N, and C-S arising from amino acids, polysaccharides, aliphatic hydrocarbons, esters, amides, lignins, alkanes, aliphatic amines, and sulfates. Physicochemical properties such as crystallite size (14.36 nm), hydrodynamic size (84.6 nm), irregular morphology, elemental composition, particle size (125 nm), crystallinity, and saturation magnetization (0.90007 emu/g) were obtained from x-ray diffractometer, dynamic light scattering, scanning electron microscopy, energy dispersive x-ray spectrometer, high-resolution transmission electron microscopy, selected area electron diffraction and vibrating sample magnetometer techniques, respectively. The cell viability showed dose-dependent cytotoxic effects and enhanced the apoptosis against Hep3B and PANC1 cancer cells. R. intricata extract capped Fe3O4 NPs could be the most appropriate and effective nanomaterial for cancer treatment and management.

Influence of Physicochemical Properties of Iron Oxide Nanoparticles on Their Antibacterial Activity

The increasing occurrence of infectious diseases caused by antimicrobial resistance organisms urged the necessity to develop more potent, selective, and safe antimicrobial agents. The unique magnetic and tunable properties of iron oxide nanoparticles (IONPs) make them a promising candidate for different theragnostic applications, including antimicrobial agents. Though IONPs act as a nonspecific antimicrobial agent, their antimicrobial activities are directly or indirectly linked with their synthesis methods, synthesizing precursors, size, shapes, concentration, and surface modifications. Alteration of these parameters could accelerate or decelerate the production of reactive oxygen species (ROS). An increase in ROS role production disrupts bacterial cell walls, cell membranes, alters major biomolecules (e.g., lipids, proteins, nucleic acids), and affects metabolic processes (e.g., Krebs cycle, fatty acid synthesis, ATP synthesis, glycolysis, and mitophagy). In this review, we will investigate the antibacterial activity of bare and surface-modified IONPs and the influence of physiochemical parameters on their antibacterial activity. Additionally, we will report the potential mechanism of IONPs' action in driving this antimicrobial activity.

Visible-light-driven TiO2@Fe2O3/Chitosan nanocomposite with promoted photodegradation of meropenem and imipenem antibiotics by peroxymonosulfate

This study assessed wastewater treatment by visible-light/Peroxymonosulfate process using its linking with TiO2@Fe3O4 nanoparticles coated on chitosan. Meropenem and Imipenem photodegradation was evaluated as a model-resistant contaminant by TiO2@Fe2O3/chitosan nanocomposite. The synthesised TiO2@Fe2O3/chitosan was characterised using various techniques. Fe2O3 and TiO2 nanoparticles on the chitosan surface were affirmed via XRD, EDX, and FTIR findings. The FESEM and TEM results verified the deposition of TiO2@Fe2O3 on the chitosan surface. Under optimum circumstances (pH = 4, catalyst dosage = 0.5 g/L, antibiotics concentration = 25 mg/L reaction time = 30 min, and PMS = 2 mM), maximum degradation efficiency was obtained at about 95.64 and 93.9% for Meropenem and Imipenem, respectively. Also, the experiments demonstrated that TiO2@Fe2O3/chitosan had a better performance than photolysis and adsorption by catalyst without visible light irradiation in degrading antibiotics. The scavenger tests confirmed that O 2 ⋅ - , SO 4 ⋅ - , HO ⋅ , and h+ are present simultaneously during the pollutant photodegradation process. After five recovery cycles, the system eliminated over 80 percent of antibiotics. It suggested that the catalyst's capacity to be reused may be cost-effective.

Reaction Atmosphere-Controlled Thermal Conversion of Ferrocene to Hematite and Cementite Nanomaterials-Structural and Spectroscopic Investigations

Recently, we have reported the influence of various reaction atmospheres on the solid-state reaction kinetics of ferrocene, where oxalic acid dihydrate was used as a coprecursor. In this light, present study discusses on the nature of decomposed materials of the solid-state reactions of ferrocene in O2, air, and N2 atmospheres. The ambient and oxidative atmospheres caused the decomposition to yield pure hematite nanomaterials, whereas cementite nanomaterials along with α-Fe were obtained in N2 atmosphere. The obtained materials were mostly agglomerated. Elemental composition of each material was estimated. Using the absorbance data, the energy band gap values were estimated and the related electronic transitions from the observed absorption spectra were explored. Urbach energy was calculated for hematite, which described the role of defects in the decomposed materials. The nanostructures exhibited photoluminescence due to self-trapped states linked to their optical characteristics. Raman spectroscopy of hematite detected seven Raman modes, confirming the rhombohedral structure, whereas the D and G bands were visible in the Raman spectra for cementite. Thus, the reaction atmosphere significantly influenced the thermal decomposition of ferrocene and controls the type of nanomaterials obtained. Plausible reactions of the undergoing solid-state decomposition have been proposed.

Transformative Dynamics: Self-Assembly of Iron Oxide Hydroxide Nanorods into Iron Oxide Microcubes for Enhanced Perfluoroalkyl Substance Remediation

We report the controlled synthesis of iron oxide microcubes (IOMCs) through the self-assembly arrays of ferric oxide hydroxide nanorods (NRs). The formation of IOMCs involves a complex interplay of nucleation, self-assembly, and growth mechanisms influenced by time, thermal treatment, and surfactant dynamics. The self-assembly of vertically aligned NRs into IOMCs is controlled by dynamic magnetism properties and capping agents like cetyltrimethylammonium bromide (CTAB), whose concentration and temperature modulation dictate growth kinetics and structural uniformity. These controlled structural growths were obtained via a hydrothermal process at 120 °C at various intervals of 8, 16, 24, and 32 h in the presence of CTAB as the capping agent. In this hydrothermal method, the formation of vertically oriented NR arrays was observed without the presence of ligands, binders, harsh drying techniques, and solvent evaporation. The formation of the self-assembly of NRs to IOMCs is obtained with an increase in saturated magnetization to attain the most stable state. The synthesized IOMCs have a uniform size, quasi-shape, and excellent dispersion. Due to its excellent magnetic and catalytic properties, IOMCs were employed to remove the various emerging pollutants known as per- and polyfluorinated substances (PFAS). Various microscopic and spectroscopic techniques were employed for the characterization and interaction studies of IOMCs with various PFAS. The interaction between IOMCs and perfluoroalkyl substances (PFAS) was investigated, revealing strong adsorption tendencies facilitated by electrostatic interactions, as evidenced by UV-vis and FT-IR spectroscopic studies. Furthermore, the higher magnetic and positive surface charge of IOMCs is responsible for an effective remediation eliminating any secondary pollution with ease of recovery after the sorption interaction studies, thereby making it practically worthwhile.

Valorization and Repurposing of Citrus limetta Fruit Waste for Fabrication of Multifunctional AgNPs and Their Diverse Nanomedicinal Applications

Herein we propose an ecofriendly process for the biofabrication of AgNPs by applying fruit waste of Citrus limetta. The aqueous extracts from the peels of the fruit were used as green chelating and stabilizing agents. Structural, optical, vibrational, morphological, and magnetic properties were established using UV-Vis (ultraviolet visible spectroscopy), XRD (X-rays diffraction), FTIR (Fourier transformed infrared spectroscopy), EDS (energy dispersive spectroscopy), SEM (scanning electron microscopy), ESR (electron spin resonance), and PPMS (physical property management system), while the thermal properties were established using TGA/DTG (thermal gravimetric analysis/derivative thermogravimetry). XRD pattern revealed intense peaks with single-phase purity, while the Debye-Scherrer approximation revealed an average crystallite size of 33.18 nm. The W-H plot revealed the size of 55.2 nm and strain 2.68 × 10-4. FTIR spectra revealed the involvement of different functional groups and major IR vibrations were observed at 2329 cm-1, 2092 cm-1, 1794 cm-1, 1268 cm-1, and 754 cm-1. TGA/DTG revealed major weight loss events at 240 °C and 360 °C. SEM revealed spherical or quasi-spherical morphology, while EDS confirmed the presence of elemental silver. The M-H behavior for all measurement temperature shows diamagnetic behavior. Electron spin resonance (ESR) revealed a high proportion of free electrons. Furthermore, the pharmacognostic and nanomedicinal potential CL-AgNPs was established using multiple in vitro and in vivo bioassays. The in vivo wound healing assays in mice revealed excellent healing potential which were similar to positive control. The percent wound healing is reported to be 93% on the 14th day of incision after application of CL-AgNPs. Bioassays were performed to assess enzyme inhibition potential of the CL-AgNPs for Alzheimer disease and antidiabetic applications. The AChE and BChE potential of the CL-AgNPs was highest at 1000 µg mL-1, i.e., 92% and 56%, respectively. The α-glucosidase inhibition potential for the CL-AgNPs was higher as compared to the α-glucosidase, while the DPPH free radical scavenging was reported to be 70% to 11% at varying concentrations between 1000 and 62.5 µg mL-1. Overall, our results indicate that the waste fruit peels can be a sustainable and eco-friendly resource of synthesis of the multifunctional nanoparticles.

Progress of disinfection catalysts in advanced oxidation processes, mechanisms and synergistic antibiotic degradation

Human diseases caused by pathogenic microorganisms make people pay more attention to disinfection. Meanwhile, antibiotics can cause microbial resistance and increase the difficulty of disease treatment, resulting in risk of triggering a vicious circle. Advanced oxidation process (AOPs) has been widely studied in the field of synergistic treatment of the two contaminates. This paper reviews the application of catalytic materials and their modification strategies in the context of AOPs for disinfection and antibiotic degradation. It also delves into the mechanisms of disinfection such as the pathways for microbial inactivation and the related influencing factors, which are essential for understanding the pivotal role of catalytic materials in disinfection principles by AOPs. More importantly, the exploratory research on the combined use of AOPs for disinfection and antibiotic degradation is discussed, and the potential and prospects in this field is highlighted. Finally, the limitations and challenges associated with the application of AOPs in disinfection and antibiotic degradation are summarized. It aims to provide a starting point for future research efforts to facilitate the widespread use of advanced oxidation processes in the field of public health.

Polymethylmethacrylate-hydroxyapatite antibacterial and antifungal activity against oral bacteria: An in vitro study

Objective

Reconstruction of alveolar bone defects resulting from aging, trauma, ablative surgery or pathology, remains a significant clinical challenge. The objective of this study was to investigate the antibacterial and antifungal activities of mixed polymethylmethacrylate-hydroxyapatite (PMMA-HA) against oral microorganisms. Our findings could provide valuable insights into the prospective application of PMMA-HA as a synthetic bone graft material to manage alveolar bone defects via tissue engineering.

Methods

HA powder was obtained from the Center for Ceramics in Indonesia and PMMA granules were obtained from HiMedia Laboratories; these were prepared in 20:80, 30:70, and 40:60 ratios. The antibacterial diffusion method was then performed against Staphylococcusaureus, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Fusobacterium nucleatum, while the antifungal diffusion method was used to test against Candida albicans. Standardized protocols were used for microbial culturing and inhibition zones were measured with digital calipers. Statistical analyses included one-way ANOVA and Kruskal-Wallis tests, supplemented by post-hoc Tukey HSD tests.

Results

A PMMA-HA scaffold with a 20:80 ratio demonstrated the highest antibacterial activity against S. aureus, A. actinomycetemcomitans, P. gingivalis, and F. nucleatum. This was followed by the 30:70 and 40:60 ratios in terms of antibacterial activity. Statistical significance was achieved with p < 0.05 in comparison to controls. However, none of the PMMA-HA ratios showed antifungal activity against C. albicans.

Conclusion

PMMA-HA scaffolds have significant activity against bacteria, but not against fungi.

Nanocomposites of iron oxide, sodium alginate, and eugenol induce apoptosis via PI3K/Akt/mTOR signaling in Hep3 cells and in vivo hepatotoxicity in the zebrafish model

Hepatic cancer is among the most recurrently detected malignancies worldwide and one of the main contributors to cancer-associated mortality. With few available therapeutic choices, there is an instant necessity to explore suitable options. In this aspect, Nanotechnology has been employed to explore prospective chemotherapeutic approaches, especially for cancer treatment. Nanotechnology is concerned with the biological and physical properties of nanoparticles in the therapeutic use of drugs. In the current work, formulation, and characterization of α-Fe2O3-Sodium Alginate-Eugenol nanocomposites (FSE NCs) using several approaches like SEM and TEM, UV-visible, FTIR, and PL spectroscopy, XRD, EDAX, and DLS studies have been performed. With an average size of 50 nm, the rhombohedral structure of NCs was identified. Further, their anticancer activity against Hep3B liver cancer cell lines has been performed by cell viability, dual staining, DCFH-DA, Annexin-V/-FITC/PI, cell cycle analysis methods, and PI3K/Akt/mTOR signaling proteins were studied to assess the anticancer effects of the NCs in Hep3B cells. Also, anti-cancer activity on animal modeling in-vivo using zebra fishes to hematological parameters, liver enzymes, and histopathology study effectiveness was noticed. Moreover, the NCs reduced the viability, elevated the ROS accumulation, diminished the membrane integrity, reduced the antioxidants, blocked the cell cycle, and triggered the PI3K/Akt/mTOR signaling axis that eventually resulted in cell death. As a result, FSE NCs possess huge potential for use as a possible anticancer candidate.

Green synthesis of iron nanoparticles: Sources and multifarious biotechnological applications

Green synthesis of iron nanoparticles is a highly fascinating research area and has gained importance due to reliable, sustainable and ecofriendly protocol for synthesizing nanoparticles, along with the easy availability of plant materials and their pharmacological significance. As an alternate to physical and chemical synthesis, the biological materials, like microorganisms and plants are considered to be less costly and environment-friendly. Iron nanoparticles with diverse morphology and size have been synthesized using biological extracts. Microbial (bacteria, fungi, algae etc.) and plant extracts have been employed in green synthesis of iron nanoparticles due to the presence of various metabolites and biomolecules. Physical and biochemical properties of biologically synthesized iron nanoparticles are superior to that are synthesized using physical and chemical agents. Iron nanoparticles have magnetic property with thermal and electrical conductivity. Iron nanoparticles below a certain size (generally 10-20 nm), can exhibit a unique form of magnetism called superparamagnetism. They are non-toxic and highly dispersible with targeted delivery, which are suitable for efficient drug delivery to the target. Green synthesized iron nanoparticles have been explored for multifarious biotechnological applications. These iron nanoparticles exhibited antimicrobial and anticancerous properties. Iron nanoparticles adversely affect the cell viability, division and metabolic activity. Iron nanoparticles have been used in the purification and immobilization of various enzymes/proteins. Iron nanoparticles have shown potential in bioremediation of various organic and inorganic pollutants. This review describes various biological sources used in the green synthesis of iron nanoparticles and their potential applications in biotechnology, diagnostics and mitigation of environmental pollutants.

In situ anchoring of iron and zinc oxides nanoparticles onto rice husk cellulose for efficient wastewater remediation

The development of effective and economical technologies for the treatment of contaminated wastewater has been of great significance to researchers. Therefore, an equal molar ratio of iron and zinc oxides nanoparticles was hydrothermally immobilized on the cellulose fibers of rice husk. Using XRD, SEM, FTIR, EDX, TEM, VSM, BET, and TGA/DTG, the structure, and characteristics of Cel/α-Fe₂O₃-ZnO, a ternary nanocomposite, were affirmed. The nanocomposite displayed a mesoporous structure with a substantial surface area. The efficiency of nanocomposite as a new adsorbent has been studied for the extraction of reactive black 5 (RB5), which is a diazo-anionic dye from simulated wastewater. The medium's pH was the dominant factor of RB5 adsorption, and the optimal removal effectiveness was acquired at pH 2. The adsorption values of RB5 correspond to second-order kinetics. They also matched Langmuir with a maximum capacity of 99.30 mg g^-1. For real industrial wastewater, Cel/α-Fe₂O₃-ZnO has successfully reduced a number of major pollutants, including ammonia (92.73 %), color (92.88 %), COD (91.53 %), BOD₅ (84.97 %), TSS (96.27 %), TP (52.17 %) and TN (47.23 %). These results illustrate the effective application of the ternary nanocomposite in wastewater treatment.

Photo-Oxidation of Organic Dye by Fe2O3 Nanoparticles: Catalyst, Electron Acceptor, and Polyurethane Membrane (PU-Fe2O3) Effects

The textile industry’s discharges have long been regarded as severe water pollution. The photocatalytic degradation of dyes using semiconductors is one of the crucial methods. The present study efficiently used the mechanical method to synthesize Iron oxide Nanoparticles. XRD, FT-IR, UV-Vis DRS, and Raman analyses were performed to analyze the structural and optical. From the data provided by XRD and Raman data, we believed that the as-synthesized Iron oxide was pure hematite (α-Fe2O3) with a hexagonal structure. Additionally, the EDS results show that the synthesized material is pure. By adjusting specific parameters, including the dye concentration, the catalyst dosage, the pH, and the oxidizing agent such as H2O2 and K2S2O8, the degradation of eosin yellowish using Fe2O3 as a photocatalyst has been discussed. Additionally, the kinetics of eosin yellowish degradation has been studied. A study was also conducted using Fe2O3 nanoparticles attached to polyurethane polymer (PU) to investigate its photocatalytic activity on methylene blue, methyl orange, and indigo carmine. In 30 minutes, nearly 90% of the dyes had degraded. The total organic carbon (TOC) analysis confirmed this result.

Photodegradation of Amido Black 10b Dye Under Visible Light Using Ni and Zn Ferrite Catalysts Prepared by a Simple Modified Sol–Gel Method

The pure α-Fe2O3, NiFe2O4, and ZnFe2O4 were prepared by a simple modified sol–gel method. The prepared catalysts were characterized by X-ray diffraction, transmission electron microscope, surface area, Zeta potential and optical techniques. The ferrite structure of samples is confirmed. The photocatalytic activity was evaluated toward Amido black 10b dye degradation under visible light at different pHs of 4, 8, and 10 for 90 min irradiation time. The photodegradation toward Amido black b10 dye reached maximum value at pH 8, and it reaches 92%, 89%, and 85% over ZnFe2O4, Fe2O3, and NiFe2O4 photocatalysts; respectively. The increased photoactivity of the ZnFe2O4 sample can also be attributed to its lower bandgap of 2 eV, the formation of the −OH-surface group. Since –OH can interact with the photoexcited holes that were originally formed on the catalyst surface, hydroxyl radicals are produced that have strong oxidizing properties. Whereas; the dye photodegradation is negligible in the case of Fe2O3, and NiFe2O4 catalysts at pH 10, due to the electrostatic repulsion between negatively charged catalyst surface and dye ions at high basic medium. While, in case of ZnFe2O4, the photodegradation reached only 40%.

Structural characterization of cuboidal α-Fe2O3 nanoparticles synthesized by a facile approach

α-Fe2O3 nanoparticles were synthesized using Tabebuia aurea leaf extract by a facile approach. The signature peaks for Fe and O in the EDX spectrum verified the formation of Fe2O3 nanoparticles. Cuboidal-shaped nanoparticles were observed in the FE-SEM image. In the XRD pattern, it was observed that the peaks belong to α-Fe2O3 nanoparticles. These particles were pure and crystalline with an average particle size of 25.69 nm. The signals at 538 and 494 cm−1 in the FTIR image confirmed the formation of hematite nanoparticles. BET analysis showed a comparatively greater surface area (31.03 m2/g) than the commercial α-Fe2O3 nanoparticles, and the pores were mesoporous. XPS analysis confirmed the existence of α-Fe2O3 by showing the specific oxidation states for iron and oxygen at 710.34 and 529.67 eV, respectively. The saturation magnetization value of 13.97 emu/g confirmed the superparamagnetic nature. The TGA, which determined the thermal stability of the nanoparticles, reported a total weight loss of 12.75%. Hence, the highly crystalline, pure, mesoporous, superparamagnetic α-Fe2O3 nanoparticles with high surface area synthesized using T. aurea leaf extract can be potentially applied in diverse fields.

Towards enhancement of fungal hydrolytic enzyme cocktail using waste algal biomass of Oscillatoria obscura and enzyme stability investigation under the influence of iron oxide nanoparticles

Development of low-cost and economic cellulase production is among the key challenges due to its broad industrial applications. One of the main topics of research pertaining to sustainable biomass waste based biorefinaries is the development of economic cellulase production strategies. The main cause of the increase in cellulase production costs is the use of commercial substrates; as a result, the cost of any cellulase-based bioprocess can be decreased by employing a productive, low-cost substrate. The goal of the current study is to develop low-cost cellulase using the carbohydrate-rich, renewable, and widely accessible cyanobacteria algae Oscillatoria obscura as the production substrate. Maximum cellulase was produced utilising the fungus Rhizopus oryzae at substrate concentration of 7.0 g among various tested concentrations of algal biomass. Maximum production rates of 22 IU/gds FP, 105 IU/gds BGL, and 116 IU/gds EG in 72 h were possible under optimal conditions and substrate concentration. Further investigations on the crude enzyme's stability in the presence of iron oxide nanoparticles (IONPs) revealed that it was thermally stable at 60 °C for up to 8 h. Additionally, the crude enzyme demonstrated pH stability by maintaining its complete activity at pH 6.0 for 8 h in the presence of the optimal dose of 15 mg IONPs. The outcomes of this research may be used to investigate the possibility of producing such enzymes in large quantities at low cost for industrial use.

Saussurea costus extract as bio mediator in synthesis iron oxide nanoparticles (IONPs) and their antimicrobial ability

Saussurea costus is from medicinal plants and have therapeutic properties that were recorded in a variety of medical functions. The usage of biomaterials in the synthesis of nanoparticles is an essential strategy in green nanotechnology. Iron oxide nanoparticles (IONPs) were composed in the stage of (2:1, FeCl2: FeCl3) solution by using the aqueous extract of Saussurea costus peel in an eco-friendly method to evaluate their antimicrobial property. The properties of the obtained IONPs were evaluated using a scanning (SEM) and transmission (TEM) electron microscope. The mean size of IONPs discovered by Zetasizer varies between 100 and 300 nm, with a mean particle size of 295 nm. The morphology of IONPs (γ-Fe2O3) was determined to be nearly spherical and prismatic-curved. Moreover, the antimicrobial property of IONPs was assessed with nine pathogenic microbes, revealing that the nanoparticles have antimicrobial activities with Pseudomonas aeruginosa, Escherichia coli, Shigella sp., Staphylococcus sp. and Aspergillus niger, with possible applications in the therapeutic and biomedical fields.

Waste toner-derived porous iron oxide pigments with enhanced catalytic degradation property

'Wealth from Waste' is an emerging concept, since it leads an effective waste treatment and waste recyclability. On the other hand, cost effective production iron oxide (IO) nanomaterials is still needed to develop, owing to their wide applications. Herein, we proposed a simple direct calcination method to prepare porous IO (Fe₃O₄ and Fe₂O₃) nanomaterials from waste toner powder. Characterization techniques reveal that a structural change happened from Fe₃O₄ to γ-Fe₂O₃ and γ-Fe₂O₃ to α-Fe₂O₃ at the calcination temperature of 500 °C and 700 °C respectively. Consequently, optical (band gap) and magnetic parameters of IO samples were significantly varied. The pigment characteristics of the IO samples were evaluated using Commission Internationale de l'Eclairage (CIE) analysis. IO900 sample has shown good brown-red coloration (L* = 43.11, a* = 13.26 and b* = 5.69) and it also exhibited good stability in acidic and basic conditions. Practical applicability of IO pigments were also tested by mixing with plaster of paris (PP) powder. Further, porous IO samples were also used as catalysts in the reductive degradation of methyl orange (MO) dye in presence of excess sodium borohydride (NaBH₄). IO, prepared at 900 °C exhibited ∼99.9% reduction efficiency within 40 min. Recycling experiments indicated that IO900 possess good stability up to seven cycles. The present porous IO samples will become potential in pigment and environmental remediation.

Nanocomposite Based on HA/PVTMS/Cl2FeH8O4 as a Gas and Temperature Sensor

In this paper, a novel nanocrystalline composite material of hydroxyapatite (HA)/polyvinyltrimethoxysilane (PVTMS)/iron(II)chloride tetrahydrate (Cl₂FeH₈-O₄) with hexagonal structure is proposed for the fabrication of a gas/temperature sensor. Taking into account the sensitivity of HA to high temperatures, to prevent the collapse and breakdown of bonds and the leakage of volatiles without damaging the composite structure, a freeze-drying machine is designed and fabricated. X-ray diffraction, FTIR, SEM, EDAX, TEM, absorption and photoluminescence analyses of composite are studied. XRD is used to confirm the material structure and the crystallite size of the composite is calculated by the Monshi-Scherrer method, and a value of 81.60 ± 0.06 nm is obtained. The influence of the oxygen environment on the absorption and photoluminescence measurements of the composite and the influence of vaporized ethanol, N₂ and CO on the SiO₂/composite/Ag sensor device are investigated. The sensor with a 30 nm-thick layer of composite shows the highest response to vaporized ethanol, N₂ and ambient CO. Overall, the composite and sensor exhibit a good selectivity to oxygen, vaporized ethanol, N₂ and CO environments.

Synthesis of Biogenic Hematite Nanocubes as Recyclable Dark Fenton-like Catalysts at Neutral pH and Plant Growth Applications of Degraded Waste Water

The goal of this study is to fabricate bioinspired metal oxide nanocubes from lemon peel extract in an environmentally friendly manner and evaluate its impact on environmental remediation. In neutral pH, the degradation kinetics of methylene blue dye (MB) in the aqueous phase was investigated using iron oxide nanoparticles as a catalyst. The obtained results revealed that under optimum conditions, synthesized Fe2O3 nanoparticles (IONPs) offered ultrafast dark Fenton-like reaction to degrade MB. The size, morphological structures, and stability were confirmed through dynamic light scattering, field emission scanning electron microscopy, X-ray diffraction, and ζ potential analysis. The overall environmental impact of the process was assessed by growing wheat plants with treated wastewater and evaluating their biochemical attributes. Antibacterial activity was investigated against Gram-positive (Bacillus megaterium, Bacillus subtilis) and Gram-negative (Escherichia coli, Salmonella typhimurium) aerobics and Gram-positive cocci (Staphylococcus aureus). The antifungal activity was measured against Fusarium solani by spore germination inhibition and zone inhibition of fungal pathogens for different nanocube concentrations.

Metal Oxide Nanoparticles: Review of Synthesis, Characterization and Biological Effects

In the last few years, the progress made in the field of nanotechnology has allowed researchers to develop and synthesize nanosized materials with unique physicochemical characteristics, suitable for various biomedical applications. Amongst these nanomaterials, metal oxide nanoparticles (MONPs) have gained increasing interest due to their excellent properties, which to a great extent differ from their bulk counterpart. However, despite such positive advantages, a substantial body of literature reports on their cytotoxic effects, which are directly correlated to the nanoparticles' physicochemical properties, therefore, better control over the synthetic parameters will not only lead to favorable surface characteristics but may also increase biocompatibility and consequently lower cytotoxicity. Taking into consideration the enormous biomedical potential of MONPs, the present review will discuss the most recent developments in this field referring mainly to synthesis methods, physical and chemical characterization and biological effects, including the pro-regenerative and antitumor potentials as well as antibacterial activity. Moreover, the last section of the review will tackle the pressing issue of the toxic effects of MONPs on various tissues/organs and cell lines.

MHD flow of time-fractional Casson nanofluid using generalized Fourier and Fick's laws over an inclined channel with applications of gold nanoparticles

Gold nanoparticles are commonly used as a tracer in laboratories. They are biocompatible and can transport heat energy to tumor cells via a variety of clinical techniques. As cancer cells are tiny, properly sized nanoparticles were introduced into the circulation for invasion. As a result, gold nanoparticles are highly effective. Therefore, the current research investigates the magnetohydrodynamic free convection flow of Casson nanofluid in an inclined channel. The blood is considered as a base fluid, and gold nanoparticles are assumed to be uniformly dispersed in it. The above flow regime is formulated in terms of partial differential equations. The system of derived equations with imposed boundary conditions is non-dimensionalized using appropriate dimensionless variables. Fourier's and Fick's laws are used to fractionalize the classical dimensionless model. The Laplace and Fourier sine transformations with a new transformation are used for the closed-form solutions of the considered problem. Finally, the results are expressed in terms of a specific function known as the Mittag-Leffler function. Various figures and tables present the effect of various physical parameters on the achieved results. Graphical results conclude that the fractional Casson fluid model described a more realistic aspect of the fluid velocity profile, temperature, and concentration profile than the classical Casson fluid model. The heat transfer rate and Sherwood number are calculated and presented in tabular form. It is worth noting that increasing the volume percentage of gold nanoparticles from 0 to 0.04 percent resulted in an increase of up to 3.825% in the heat transfer rate.

Evaluation of the Antibacterial Properties of Iron Oxide, Polyethylene Glycol, and Gentamicin Conjugated Nanoparticles against Some Multidrug-Resistant Bacteria

Antibacterial resistance is observed as a public health issue around the world. Every day, new resistance mechanisms appear and spread over the world. For that reason, it is imperative to improve the treatment schemes that have been developed to treat infections caused by wound infections, for instance, Staphylococcus epidermidis (S. epidermidis), Proteus mirabilis (P. mirabilis), and Acinetobacter baumannii (A. baumannii). In this case, we proposed a method that involves mixing the Gentamicin (Gen) with iron oxide nanoparticles (Fe3O4 NPs) and a polymer (polyethylene glycol (PEG)) with Fe3O4 NPs. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), energy dispersive X-ray (EDX), scanning electron microscope (SEM), and transmission electron microscope (TEM) were used to characterize Fe3O4 NPs. Zeta potential and dynamic light scattering (DLS) were also assessed. The antibacterial activity of Fe3O4 NPs, Fe3O4 NPs+PEG, Fe3O4 NPs+Gen, and Fe3O4 NPs+PEG+Gen composites was investigated. The results showed a significant improvement in the antibacterial activity of nanoparticles against bacterial isolates, especially for the Fe3O4 NPs+PEG+Gen as the diameter of the inhibition zone reached 26.33 ± 0.57 mm for A. baumannii, 25.66 ± 0.57 mm for P. mirabilis, and 23.66 ± 0.57 mm for S. epidermidis. The Fe3O4 NPs, Fe3O4 NPs+PEG, Fe3O4+Gen, and Fe3O4+PEG+Gen also showed effectiveness against the biofilm produced by these isolated bacteria. The minimum inhibitory concentration (MIC) of Fe3O4 NPs for S. epidermidis was 25 µg mL−1 and for P. mirabilis and A. baumannii was 50 µg mL−1. The findings suggest that the prepared nanoparticles could be potential therapeutic options for treating wound infections caused by S. epidermidis, P. mirabilis, and A. baumannii.

Biogenic Synthesis, Characterization, and Photocatalytic Evaluation of Pristine and Graphene-Loaded Zn50Mg50O Nanocomposites for Organic Dyes Removal

Algal biomass synthesised nanocomposites have a higher surface area and reusability advantages. This study aimed to synthesise and characterise ZnMgO and silica-supported graphene with ZnMgO (G-ZnMgO) nanocomposites from Kappaphycusalvarezii and evaluate their potential in the application of photocatalysis to remove Rhodamine-B (RhB) and methylene blue (MB) dyes from their aqueous medium by maximising the percentage removal using response surface methodology (RSM) modelling. Nanocomposites were synthesised and characterised by biogenic and instrumental (Powder X-ray diffraction (P-XRD), electron microscopic analysis (SEM and TEM), Fourier transform infrared spectroscopy (FTIR), Energy dispersive analysis of X-rays (EDAX). and UV-visible diffuse reflectance spectroscopy (UV-DRS)) methods, respectively; modelling predicted the optimal conditions to be photocatalyst dosage and contact time of 1 g/L and 90 min, respectively, to obtain maximum MB dye removal of 80% using G-ZnMgO. The results showed the best fit between experimental and RSM predicted values. Thus, the obtained results conclude that the algal biomass synthesised nanocomposites were found to be one of the potential photocatalysts for the removal of RhB and MB dyes from their aqueous solution.

Hepatotoxic and Neurotoxic Potential of Iron Oxide Nanoparticles in Wistar Rats: a Biochemical and Ultrastructural Study

Iron oxide nanoparticles (IONPs) are increasingly being employed for in vivo biomedical nanotheranostic applications. The development of novel IONPs should be accompanied by careful scrutiny of their biocompatibility. Herein, we studied the effect of administration of three formulations of IONPs, based on their starting materials along with synthesizing methods, IONPs-chloride, IONPs-lactate, and IONPs-nitrate, on biochemical and ultrastructural aspects. Different techniques were utilized to assess the effect of different starting materials on the physical, morphological, chemical, surface area, magnetic, and particle size distribution accompanied with their surface charge properties. Their nanoscale sizes were below 40 nm and demonstrated surface up to 69m²/g, and increased magnetization of 71.273 emu/g. Moreover, we investigated the effects of an oral IONP administration (100 mg/kg/day) in rat for 14 days. The liver enzymatic functions were investigated. Liver and brain tissues were analyzed for oxidative stress. Finally, a transmission electron microscope (TEM) and inductively coupled plasma optical emission spectrometer (ICP-OES) were employed to investigate the ultrastructural alterations and to estimate content of iron in the selected tissues of IONP-exposed rats. This study showed that magnetite IONPs-chloride exhibited the safest toxicological profile and thus could be regarded as a promising nanotherapeutic candidate for brain or liver disorders.

Photocatalytic Dye Degradation and Bio-Insights of Honey-Produced α-Fe2O3 Nanoparticles

Iron oxide nanoparticles are produced using simple auto combustion methods with honey as a metal-stabilizing and -reducing agent. Herein, α-Fe2O3 nanoparticles are produced using an iron nitrate precursor. These prepared samples are analyzed by an X-ray diffractometer (XRD), FTIR spectroscopy, UV-DRS, and a field-emission scanning electron microscope (FESEM) combined with energy-dispersive spectroscopy and a vibrating sample magnetometer (VSM). The XRD results confirm a rhombohedral structure with an R3c¯ space group single-phase formation of α-Fe2O3 in all samples. FESEM images reveal the different morphologies for the entire three samples. TEM analysis exhibits spherical shapes and their distribution on the surfaces. XPS spectroscopy confirms the Fe-2p and O-1s state and their valency. The VSM study shows strong ferromagnetic behavior. The prepared α-Fe2O3 nanoparticles exhibit exceptional charge carriers and radical production. The prepared sample retains excellent photocatalytic, antifungal and antibacterial activity.

Biosynthesis of Iron Oxide Nanoparticles: Physico-Chemical Characterization and Their In Vitro Cytotoxicity on Healthy and Tumorigenic Cell Lines

Iron oxide nanoparticles were synthesized starting from two aqueous extracts based on Artemisia absinthium L. leaf and stems, employing a simplest, eco-friendliness and low toxicity method—green synthesis. The nanoparticles were characterized by powder X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR), X-ray fluorescence analysis (XRF), thermal analysis (TG/DSC), and scanning electron microscopy (SEM). Lack of magnetic properties and the reddish-brown color of all the samples confirms the presence of hematite as majority phase. The FTIR bands located at 435 cm⁻¹ and 590 cm⁻¹, are assigned to Fe-O stretching vibration from hematite, confirming the formation of α-Fe₂O₃ nanoparticles (NPs). The in vitro screening of the samples revealed that the healthy cell line (HaCaT) presents a good viability (above 80%) after exposure to iron oxide NPs and lack of apoptotic features, while the tumorigenic cell lines manifested a higher sensitivity, especially the melanoma cells (A375) when exposed to concentration of 500 µg/mL iron oxide NPs for 72 h. Moreover, A375 cells elicited significant apoptotic markers under these parameters (concentration of 500 µg/mL iron oxide NPs for a contact time of 72 h).

Nanoparticle classification, physicochemical properties, characterization, and applications: a comprehensive review for biologists

Interest in nanomaterials and especially nanoparticles has exploded in the past decades primarily due to their novel or enhanced physical and chemical properties compared to bulk material. These extraordinary properties have created a multitude of innovative applications in the fields of medicine and pharma, electronics, agriculture, chemical catalysis, food industry, and many others. More recently, nanoparticles are also being synthesized ‘biologically’ through the use of plant- or microorganism-mediated processes, as an environmentally friendly alternative to the expensive, energy-intensive, and potentially toxic physical and chemical synthesis methods. This transdisciplinary approach to nanoparticle synthesis requires that biologists and biotechnologists understand and learn to use the complex methodology needed to properly characterize these processes. This review targets a bio-oriented audience and summarizes the physico–chemical properties of nanoparticles, and methods used for their characterization. It highlights why nanomaterials are different compared to micro- or bulk materials. We try to provide a comprehensive overview of the different classes of nanoparticles and their novel or enhanced physicochemical properties including mechanical, thermal, magnetic, electronic, optical, and catalytic properties. A comprehensive list of the common methods and techniques used for the characterization and analysis of these properties is presented together with a large list of examples for biogenic nanoparticles that have been previously synthesized and characterized, including their application in the fields of medicine, electronics, agriculture, and food production. We hope that this makes the many different methods more accessible to the readers, and to help with identifying the proper methodology for any given nanoscience problem.

Composite Materials Based on Gelatin and Iron Oxide Nanoparticles for MRI Accuracy

The majority of recent studies have focused on obtaining MRI materials for internal use. However, this study focuses on a straightforward method for preparing gelatin-based materials with iron oxide nanoparticles (G-Fe2O3 and G-Fe3O4) for external use. The newly obtained materials must be precisely tuned to match the requirements and usage situation because they will be in close touch with human/animal skin. The biocompatible structures formed by gelatin, tannic acid, and iron oxide nanoparticles were investigated by using FTIR spectroscopy, SEM-EDAX analysis, and contact angle methods. The physico-chemical properties were obtained by using mechanical investigations, dynamic vapor sorption analysis, and bulk magnetic determination. The size and shape of iron oxide nanoparticles dictates the magnetic behavior of the gelatin-based samples. The magnetization curves revealed a typical S-shaped superparamagnetic behavior which is evidence of improved MRI image accuracy. In addition, the MTT assay was used to demonstrate the non-toxicity of the samples, and the antibacterial test confirmed satisfactory findings for all G-based materials.

Systematic Investigation of Structural, Morphological, Thermal, Optoelectronic, and Magnetic Properties of High-Purity Hematite/Magnetite Nanoparticles for Optoelectronics

Iron oxide nanoparticles, especially hematite (α-Fe2O3) and magnetite (Fe3O4) have attained substantial research interest in various applications of green and sustainable energy harnessing owing to their exceptional opto-magneto-electrical characteristics and non-toxicity. In this study, we synthesized high-purity hematite and magnetite nanoparticles from a facile top-down approach by employing a high-energy ball mill followed by ultrasonication. A systematic investigation was then carried out to explore the structural, morphological, thermal, optoelectrical, and magnetic properties of the synthesized samples. The experimental results from scanning electron microscopy and X-ray diffraction corroborated the formation of highly crystalline hematite and magnetite nanoparticles with average sizes of ~80 nm and ~50 nm, respectively. Thermogravimetric analysis revealed remarkable results on the thermal stability of the newly synthesized samples. The optical studies confirmed the formation of a single-phase compound with the bandgaps dependent on the size of the nanoparticles. The electrochemical studies that utilized cyclic voltammetry and electrochemical impedance spectroscopy techniques verified these iron oxide nanoparticles as electroactive species which can enhance the charge transfer process with high mobility. The hysteresis curves of the samples revealed the paramagnetic behavior of the samples with high values of coercivity. Thus, these optimized materials can be recommended for use in future optoelectronic devices and can prove to be potential candidates in the advanced research of new optoelectronic materials for improved energy devices.

Superparamagnetic hematite spheroids synthesis, characterization, and catalytic activity

The leaf extract of Muntingia calabura is being first reported to be used for the synthesis superparamagnetic hematite nanoparticles by following the green-chemistry approach. Field Emission - Scanning Electron Microscopic image revealed the formation of irregular nano spheroids averaging at 48.57 nm in size and characteristic of Fe and O atoms, as revealed by Energy Dispersive X-Ray spectrum. X-ray diffraction analysis results proved the crystallinity of hematite diffraction planes with crystallite sizes averaging at 30.68 nm. The lattice parameter values stayed concordant with the literature. The superparamagnetic nature was attested by the high value of saturation magnetism (2.20 emu/g) with negligible coercivity and retentivity. Fourier Transform Infrared Spectroscopy results affirmed numerous moieties involved in the synthesis of hematite nanoparticles and the existence of signature Fe-O bands. Thermogravimetric analysis studies portrayed the thermal behavior nanoparticles with 28% weight loss and thermal stability was attained after 700 °C. X-ray photoelectron spectroscopy analysis confirmed the valence states of Fe and O in the hematite nanoparticles and ascertained the purity. The mesoscopic structure was revealed by Brunauer-Emmett-Teller studies with considerable surface area (112.50 m²/g). The Fenton-like catalysis mediated by the nanoparticle sample was demonstrated by degrading methylene blue dye. The remarkable degradation efficiency of 93.44% was obtained and the kinetics was conformed to a second-order model with a high R² value. Therefore, the highly crystalline and mesoporous superparamagnetic hematite spheroids prepared using the leaf extract of M. calabura would find promising applications in various catalysis processes.

Preparation, Characterization, and Electrochemical Performance of the Hematite/Oxidized Multi-Walled Carbon Nanotubes Nanocomposite

In this research work, a hematite (α-Fe₂O₃) nanoparticle was prepared and then mixed with oxidized multi-walled carbon nanotubes (O-MWCNT) to form a stable suspension of an α-Fe₂O₃/O-MWCNTs nanocomposite. Different characterization techniques were used to explore the chemical and physical properties of the α-Fe₂O₃/O-MWCNTs nanocomposite, including XRD, FT-IR, UV-Vis, and SEM. The results revealed the successful formation of the α-Fe₂O₃ nanoparticles, and the oxidation of the MWCNT, as well as the formation of stable α-Fe₂O₃/O-MWCNTs nanocomposite. The electrochemical behaviour of the α-Fe₂O₃/O-MWCNTs nanocomposite was investigated using cyclic voltammetry (CV) and linear sweep voltammetry (LSV), and the results revealed that modification of α-Fe₂O₃ nanoparticles with O-MWCNTs greatly enhanced electrochemical performance and capacitive behaviour, as well as cycling stability.

The Antioxidant Effect of the Metal and Metal-Oxide Nanoparticles

Inorganic nanoparticles, such as CeO₃, TiO₂ and Fe₃O₄ could be served as a platform for their excellent performance in antioxidant effect. They may offer the feasibility to be further developed for their smaller and controllable sizes, flexibility to be modified, relative low toxicity as well as ease of preparation. In this work, the recent progress of these nanoparticles were illustrated, and the antioxidant mechanism of the inorganic nanoparticles were introduced, which mainly included antioxidant enzyme-mimetic activity and antioxidant ROS/RNS scavenging activity. The antioxidant effects and the applications of several nanoparticles, such as CeO₃, Fe₃O₄, TiO₂ and Se, are summarized in this paper. The potential toxicity of these nanoparticles both in vitro and in vivo was well studied for the further applications. Future directions of how to utilize these inorganic nanoparticles to be further applied in some fields, such as medicine, cosmetic and functional food additives were also investigated in this paper.

α-Fe2O3 Nanoparticles Aided-Dual Conversion for Self-Powered Bio-Based Photodetector

Eco-friendly energy harvesting from the surrounding environment has been triggered extensive researching enthusiasm due to the threat of global energy crisis and environmental pollutions. By the conversion of mechanical energy that is omnipresent in our environment into electrical energy, triboelectric nanogenerator (TENG) can potentially power up small electronic devices, serves as a self-powered detectors and predominantly, it can minimize the energy crisis by credibly saving the traditional non-renewable energy. In this study, we present a novel bio-based TENG comprising PDMS/α-Fe2O3 nanocomposite film and a processed human hair-based film, that harvests the vibrating energy and solar energy simultaneously by the integration of triboelectric technology and photoelectric conversion techniques. Upon illumination, the output voltage and current signals rapidly increased by 1.4 times approximately, compared to the dark state. Experimental results reveal that the photo-induced enhancement appears due to the effective charge separation depending on the photosensitivity of the hematite nanoparticles (α-Fe2O3 nanoparticles) over the near ultraviolet (UV), visible and near infrared (IR) regions. Our work provides a new approach towards the self-powered photo-detection, while developing a propitious green energy resource for the circular bio-economy.

Multivariate metal-organic framework MTV-MIL-101 via post-synthetic cation exchange: is it truly achievable?

The post-synthetic exchange (PSE) method is a well-proven route to replace, modify, and add different functionalities to metal-organic frameworks (MOFs). Particularly, the solvent-assisted cation substitution (SACS) technique has been reported to prepare mixed-metal multivariate metal-organic frameworks (MTV-MOFs). However, such a technique does not apply to all types of MOFs. In 2013, Szilágyi et al. reported the achievement of the mixed-metal MTV-MIL-101 framework via PSE. Since then, a debate has been taking place about the validity of these findings. On the other hand, the attainment of the mixed-metal MIL-101 was reported to be obtainable through the direct synthesis, which is, to some, the only way to achieve it. Here, we settle this dispute by investigating Szilágyi's method not only as described, but also at extended conditions of time and different metal precursors: all attempts were vain. However, by reconsidering the refluxing solvent (dimethylformamide "DMF" instead of water) and the applied reaction conditions (110 °C-20 h), mixed-metal MIL-101(Cr/Fe) was achieved via a simple PSE method.

Hematite nanoparticles decorated nitrogen-doped reduced graphene oxide/graphitic carbon nitride multifunctional heterostructure photocatalyst towards environmental applications

The carcinogenic heavy metals and aromatic organic compounds linger as wastewater pollutants implying great menace to the ecological balance. To solve these environmental pollution problems, the photocatalytic process is an...