O4 Nanoparticles Research Articles

Comparison analysis on biohydrogen production of mesophilic and thermophilic dark fermentation using nickel doped lanthanum-iron oxide nanoparticles as supplementation

In this work, perovskite-structured LaNi0.5Fe0.5O3 nanoparticles (NPs) are successfully synthesized to explore influence of addition amounts on biohydrogen yield. The great potential advantages to improve the biohydrogen production under mesophilic and thermophilic dark fermentation are systematically investigated by a series of experiments. The characterization of physicochemical properties of LaNi0.5Fe0.5O3 NPs are summarized and analyzed. The highest biohydrogen yield 262.55 mL/g of mesophilic dark fermentation is obtained at 100 mg/L LaNi0.5Fe0.5O3 NPs group while under thermophilic condition, the maximum of biohydrogen production is only 182.13 mL/g with 200 mg/L LaNi0.5Fe0.5O3 supplementation, which are higher 50.7% and 91.0% than that of corresponding control groups, respectively. The analysis of soluble microbial products (SMPs) suggests that LaNi0.5Fe0.5O3 NPs can observably enhance the butyrate-type metabolic pathway, being consistent with the raising abundance of Clostridium butyricum in mesophilic fermentation. The extracellular polymer content is significantly increased with appropriate addition of LaNi0.5Fe0.5O3 NPs. The results reveal that the moderate amount of LaNi0.5Fe0.5O3 NPs can even optimize the microbial community structure by increasing the abundance of Clostridium sensu stricto 1 under mesophilic fermentation and Clostridium sensu stricto 7 as well as Longonea under thermophilic fermentation. Eventually, it can be affirmatively concluded that the application of LaNi0.5Fe0.5O3 NPs to dark fermentation contributes to more biohydrogen yield with moderate amounts under both mesophilic and thermophilic conditions. The innovative work of nickel doped lanthanum-iron oxide nanoparticles provides an effective strategy to take the fully advantage of Fe and Ni element for biohydrogen yield.

Ru-Doped Co3O4 Nanoparticles as Efficient and Stable Electrocatalysts for the Chlorine Evolution Reaction.

The electrochemical chlorine evolution reaction (CER) is one of the most important electrochemical reactions. Typically, iridium (Ir)- or ruthenium (Ru)-based mixed metal oxides have been used as electrocatalysts for the CER due to their high activities and durabilities. However, the scarcity of Ir and Ru has indicated the need to develop alternative earth-abundant transition-metal-based CER catalysts. In this study, we report a Co3O4 nanoparticle (NP) catalyst synthesized by a hydrothermal method. Furthermore, Ru was successfully incorporated into the Co3O4 NPs (RuxCo3-xO4 NPs) for further improvement of catalytic performance in chlorine generation. Electrokinetic analyses combined with in situ X-ray absorption near-edge structure (XANES) results suggested an identical CER mechanism for the Co3O4 NPs and RuxCo3-xO4 NPs. Various characterization techniques demonstrated that the homogeneous substitution of Ru4+ ions into the Co3+ octahedral sites enhanced the structural disorder and changed the electronic state of Co3O4, resulting in additional exposed active sites. Remarkably, the Ru0.09Co2.91O4 NP electrode exhibited outstanding stability for more than 150 h even at a high current density of 500 mA/cm2, which shows its commercial viability for active chlorine generation.

Screening of Cu4 O3 NPs efficacy and its anticancer potential against cervical cancer.

Cu4 O3 is the least explored copper oxide, and its nanoformulation is anticipated to have important therapeutic potential especially against cancer. The current study aimed to biosynthesize Cu4 O3 nanoparticles(NPs) using an aqueous extract of pumpkin seeds and evaluate its antiproliferative efficacy against cervical cells after screening on different cancer cell lines.The obtained NPs were characterized by different spectroscopic analyses, such as UV-vis, thermogravimetric,energy dispersive X-ray,and Fourier-transform infrared spectroscopy (FTIR). In addition, high-resolution transmission electron microscopes (HR-TEM) were used to observe the morphology of the biosynthesized NPs. The UV-vis spectra showed a peak at around 332 nm, confirming the formation of Cu4 O3 NPs. Moreover, FTIR and TAG analyses identified the presence of various bioactive phytoconstituents that might have worked as capping and stabilization agents and comparative stable NPs at very high temperatures, respectively. The HR-TEM data showed the spherical shape of Cu4 O3 NPs in the range of 100 nm. The Cu4 O3 NPs was screened on three different cancer cell lines viz., Hela, MDA-MB-231, and HCT-116 using cytotoxicity(MTT) reduction assay. In addition, Vero was taken as a normal epithelial (control) cell. The high responsive cell line in terms of least IC50 was further assessed for its anticancer potential using a battery of biological tests, including morphological alterations, induction of apoptosis/ROS generation, regulation of mitochondrial membrane potential (MMP), and suppression of cell adhesion/migration. Vero cells (control) showed a slight decline in % cell viability even at the highest tested Cu4 O3 NPs concentration. However, all the studied cancer cells viz., MDA-MB-231, HCT 116, and HeLa cells showed a dose-dependent decline in cell viability after the treatment with Cu4 O3 NPs with a calculated IC50 value of 10, 11, and 7.2 µg/mL, respectively. Based on the above data, Hela cells were chosen for further studies, that showed induction of apoptosis from 3.5 to 9-folds by three different staining techniques acridine orange/ethidium bromide (AO/EB), 4',6-diamidino-2-phenylindole (DAPI), and propidium iodide (PI). The enhanced production of reactive oxygen species(>3.5-fold), modulation in MMP, and suppression of cell adhesion/migration were observed in the cells treated with Cu4 O3 NPs.The current study obtained the significant antiproliferative potential of Cu4 O3 NPs against the cervical cancer cell line, which needs to be confirmed further in a suitable in vivo model. Based on our results, we also recommend the green-based, eco-friendly, and cost-effective alternative method for synthesizing novel nanoformulation.

Coupling high entropy oxide with hollow carbon spheres by rapid microwave solvothermal strategy for boosting oxygen evolution reaction

High entropy oxides (HEOs) are promising oxygen evolution electrocatalysts due to the unique structure, inherent tunability, as well as excellent catalytic activity and stability. Herein, (FeCoNiCrMn)3O4 nanoparticles coupling with the hollow-mesoporous carbon spheres (HCS) has been designed and fabricated by a rapid and efficient microwave solvothermal followed by annealing. The prepared (FeCoNiCrMn)3O4 nanoparticles are highly dispersed on the HCS surface with an average particle size of approximately 3.3 nm. The composite with large surface areas can facilitate mass transfer and gas release, and it allows more active sites to be exposed. The obtained (FeCoNiCrMn)3O4/hollow-mesoporous carbon sphere composite catalyst with the optimal HEO load (HEO/HCS-3) exhibits outstanding oxygen evolution reaction (OER) electrocatalytic performance with a low overpotential of 263 mV at 10 mA cm−2, and a small Tafel slope of 41.24 mV dec−1, better than the pure (FeCoNiCrMn)3O4 and commercial RuO2 catalyst. The long-term durability of HEO/HCS-3 is also achieved by continuous electrolysis in 1 M KOH solution for more than 100 h. The outstanding catalytic performance of the composite can be ascribed to the clever structural design and the well-matched synthetic method. This research can guide the construction of high-efficient OER catalysts.

Iron oxide polyaniline-coated nanoparticles modulate tumor microenvironment in breast cancer: an in vitro study on the reprogramming of tumor-associated macrophages

BackgroundBreast cancer is the neoplastic disease with the highest incidence and mortality in the female population worldwide. Treatment remains challenging due to various factors. Therefore, it is of great importance to develop new therapeutic strategies that promote the safe destruction of neoplastic cells without compromising patients' quality of life. Among advances in the treatment of breast cancer, immunotherapy stands out as a promising trend. Recent studies have demonstrated the potential of iron oxide nanoparticles in promoting the reprogramming of M2 macrophages (pro-tumor phenotype) into M1 macrophages (anti-tumor phenotype) within the tumor microenvironment, resulting in potent antitumor effects. In this study, the effect of polyaniline-coated iron oxide nanoparticles (Pani/y-Fe2O3) on macrophage polarization and breast cancer cell death was investigated.MethodsThe non-cytotoxic concentration of nanoparticles was determined using the MTT assay. For in vitro co-culture experiments, breast cancer cell lines MCF -7 and MDA-MB -231 and macrophages THP-1 were co-cultured in a Transwell system and then the effects of Pani/y-Fe2O3 on cell viability, gene expression, cytokine profile, and oxidative stress markers were investigated.ResultsThe results showed that Pani/y-Fe2O3 nanoparticles induced M2-to-M1 macrophage polarization in both cell lines through different pathways. In MCF -7 and THP-1 macrophage co-culture, the study showed a decrease in cytokine levels IL -1β, upregulation of M1-associated genes (IL-12, TNF-α) in macrophages, resulting in increased MCF -7 cell death by apoptosis (caspase 3/7+). In MDA-MB -231 co-cultures, increases in cytokines IL -6, IL -1β, and oxidative stress markers were observed, as well as upregulation of the inducible nitric oxide synthase (iNOS) gene in macrophages, leading to tumor cell death via apoptosis-independent pathways (Sytox+).ConclusionsThese findings highlight the potential of Pani/y-Fe2O3 as a promising therapeutic approach in the context of breast cancer treatment by effectively reprogramming M2 macrophages into an anti-tumor M1 phenotype, Pani/y-Fe2O3 nanoparticles demonstrated the ability to elicit antitumor effects in both MCF-7 and MDA-MB-231 breast cancer cell lines.

Oxygen vacancy enhanced magnetic heating efficiency of ferrite nanoparticles for self-regulating temperature hyperthermia

Precise and controllable temperature is required for using magnetic hyperthermia in cancer therapy. Magnetic nanoparticles typically need to have a Curie temperature of 42–50 °C to self-regulate hyperthermia temperature via magnetic phase transition. For now, the most studied iron oxide nanoparticles are not suitable for self-regulating hyperthermia applications due to their high Curie temperature of several hundred Celsius degrees. Doping nonmagnetic metal ions into iron oxide nanoparticles is an effective way to decrease Curie temperature, but often leads to low saturation magnetization and poor magnetic heating efficiency, limiting its usage in hyperthermia applications. Magnetic nanoparticles with excellent magnetic heating efficiency and suitable Curie temperature are highly desirable. This paper proposes an approach for enhancing magnetic heating efficiency by regulating oxygen vacancy concentration. Mn0.46Zn0.54Al0.25Fe1.75O4 nanoparticles with Curie temperature at 44.5 °C are prepared by co-precipitation method. Effective regulation of oxygen vacancy concentrations is achieved through hydrogen peroxide oxidation and carbothermal reduction treatments. Research results suggest that increasing oxygen vacancies significantly enhance the magnetism due to the transformation of magnetic couplings on nanoparticles, while barely affecting the Curie temperature. These nanoparticles exhibit high magnetic heating efficiency under an alternating magnetic field, almost 1.5 times of clinical-grade iron oxide nanoparticles, and can self-regulate hyperthermia temperature at 48–49 °C. This work may provide some references for further research on self-regulating temperature magnetic hyperthermia.

Ultralight reduced graphene oxide/SiO2–C nanofibers composite aerogel decorated with Li0.35Zn0.3Fe2.35O4 nanoparticles with a three-dimensional bridging network for efficient electromagnetic wave absorption

Developing flexible, lightweight, and highly efficient electromagnetic wave (EMW) absorption materials was an effective strategy for mitigating the adverse health effects of microwaves. However, synthesizing flexible wave-absorbing aerogels via a novel method is challenging. In this study, a 3D porous reduced graphene oxide (RGO)/SiO2–C nanofibers (NFs)/Li0.35Zn0.3Fe2.35O4 (LZFO) flexible composite aerogel with a crosslinked structure was synthesized via electrospinning, freeze-drying, and in situ curing. To achieve this, electrospun SiO2 and polyacrylonitrile NFs, graphene oxide (GO), and LZFO nanoparticles were uniformly dispersed in an aqueous solution containing (Al(H3PO4)3) as a crosslinking agent and a crosslinked aerogel was formed by freeze-drying, pre-oxidation and carbonization. The obtained aerogels exhibited a good 3D porous structure. By introducing (Al(H3PO4)3) the cell binding force between the 0D, 1D and 2D materials was improved. Further, the introduction of SiO2 NFs reduced the brittleness of the C NFs and improved the flexibility of the aerogel. Under 60% strain, the stress reached 132 kPa, and a complete closed loop was formed. The RGO and C NFs conductive network coupled with the LZFO nanoparticles magnetic network form an ideal impedance matching. The minimum reflection loss (RLmin) of the RGO/SiO2–C NFs/LZFO-2 aerogel reached −55.2 dB (2.5 mm), and effective absorption bandwidth (EAB) was 5.5 GHz (2 mm) to cover the entire X-band. Moreover, by adjusting the matching thickness (2–4 mm), the RLmin was below −20 dB, and more than 99% of the EMW was absorbed. This study provides a new way to develop flexible absorbent materials for human protection.

Coeffect of Co-Mn in bimetallic oxide catalyst for ultrafast electrochemical reduction of nitrate: Insight into ion interaction

Co3O4 has been considered as promising catalysts for electroreduction of nitrate (ERN), which is an emerging tactic to close the nitrogen cycle on earth. However, the nitrate reduction efficiency of Co3O4 is less than satisfactory, which could be enhanced by assistance of Mn element. Herein, we synthesized Co3O4, Mn2O3 and Mn1.5Co1.5O4 nanoparticles for electrodes via a simple sol–gel method using metal nitrates. Moreover, a special electrode 3-Mn/Co was fabricated by physical mixed Co3O4 and Mn2O3. Mn1.5Co1.5O4 and 3-Mn/Co electrodes presented 78.6 % and 64.09 % nitrate removal efficiency after 3 h, 115.46 % and 75.68 % higher than that of Co3O4, proving the existence of Co-Mn coeffect. The optimum Mn1.5Co1.5O4 endures operating parameters experiments of applied potential, level of NO3– concentration, pH value and Cl- concentration and maintains solid stability through ten batches of reaction. Eventually, the ion valence changes of electrodes before and after electrocatalysis verifies that both Co and Mn function in the reaction. The ERN performance variation between electrodes, doped and physically mixed with Mn, and Co3O4 further elucidates that Mn3+ takes major effect in ERN process, while Mn4+ would blocks the electrons transferred to NO3–. In general, a novel process of Co3+/Mn3+- Co2+/Mn4+ reaction cycle in Co and Mn bimetallic and monometallic oxides for ERN performance is proposed as a clue for electrode fabrication.

Combustion and secondary atomization behavior of nanofuel droplets laden with hematite, magnetite and lanthanum orthoferrites nanoparticles**

AbstractCurrent research concerns the droplet combustion behavior of gasoline‐based nanofuel droplets containing hematite (Fe2O3), magnetite (Fe3O4) and lanthanum orthoferrites (LaFeO3, La0.5Fe1.5O3 and La0.75Fe1.25O3) perovskite type nanoparticles (NPs) at 2.5 % wt. particle loadings. The results showed that the size distribution of hematite and magnetite NPs is on the 90–100 nm scale, while the lanthanum orthoferrites NPs have a particle size distribution of 25–40 nm. The particles with the largest surface area (78,5098 m2/g) and enhanced oxygen adsorbing ability were La0.5Fe1.5O3 NPs. Droplet combustion experiments were recorded with a high speed camera and a 7.5–14 μm spectral area thermal camera. Fe3O4 and LaFeO3 NPs high agglomerate tendency allowed only a single microexplosion event in nanofuel droplets towards the end of the experiment. Only the G/La0.5Fe1.5O3 fuel droplets trended to obey the D2‐law. Nanofuel droplets containing La0.5Fe1.5O3 NPs exhibited the highest maximum flame temperature of 264 °C. The catalytic activity of lanthanum orthoferrite perovskite‐type NPs during combustion was improved due to the decrease in the La ratio in the A‐site and the increase in the Fe ratio in the B‐site.

Enhanced Structural and Electrochemical Properties of Zn-Doped NiCo2O4 Synthesized by Low-Temperature Microwave Hydrothermal Process

The specific capacitance (Cp) is an important parameter influencing the energy storage capacity of materials. In this study, a series of NiZn x Co2-x O4 (x = 0.0–0.10) nanoparticles were prepared using the microwave-hydrothermal (M-H) method. The samples were characterized by using X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier transform Infrared (FTIR), X-ray photoelectron spectroscopy (XPS) and electrochemical studies. It is observed from X-ray diffraction that all the samples are cubic in nature with space group Fd-3m. The average lattice constant is varied in between 7.63 (x = 0.0) to 8.34 (x = 0.10). The linear increase in lattice constant is due to the difference in the ionic radii. The average grain size is in the range of 80 (x = 0.0) − 124 nm (x = 0.10) for all the samples, and grains are found to be spherical in nature. The characteristic metal oxygen vibration bands were observed at 578 cm−1 and 661 cm−1. The valence states of Ni2+/Ni3+, Co2+/Co3+ and Zn2+ were confirmed by X-ray photoelectron spectroscopy. The electrochemical studies were performed on all the samples. The high value of specific capacitance (Cp) 871.91 Fg−1 is observed for sample x = 0.06. Therefore, Zn doped NiCo2O4 shows good impedance and electrochemical properties which is promising material for supercapacitor applications.

Structural, Optical, Magnetic and Dielectric Properties of Ce-Doped MgFe2O4 Prepared by Microwave Hydrothermal Method

The microwave hydrothermal method has been used to synthesize MgFe2-x Ce x O4 (x = 0.0 – 0.10) nanoparticles, which have been characterized using X-ray diffraction (XRD), fourier transform Infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), UV–vis spectrometer, vibrating sample magnetometer (VSM) and dielectric properties. XRD investigation confirms the cubic spinel structure, and the Debye–Scherrer formula was used to determine the crystallite size, showing values of 19 – 108 nm. FTIR confirms the presence of all functional groups and FE-SEM displays particle-like morphology. The UV-visible analysis was used to explain the variation of the optical bandgap as Ce3+ doping increased. VSM analysis of MgFe2-x Ce x O4 showed ferromagnetic behaviour. The samples exhibit low magnetization values ranging from 8.83 emu g−1 to 18.91 emu g−1. The values of the dielectric constant (ε′) and the dielectric loss (tanδ) decreased with frequency due to the influence of space-charge polarization and showed a dispersive behaviour at higher frequencies.

In Situ Transmission Electron Microscopy to Study the Location and Distribution Effect of Pt on the Reduction of Co3 O4 -SiO2.

The addition of Pt generally promotes the reduction of Co3 O4 in supported catalysts, which further improves their activity and selectivity. However, due to the limited spatial resolution, how Pt and its location and distribution affect the reduction of Co3 O4 remains unclear. Using ex situ and in situ ambient pressure scanning transmission electron microscopy, combined with temperature-programmed reduction, the reduction of silica-supported Co3 O4 without Pt and with different location and distribution of Pt is studied. Shrinkage of Co3 O4 nanoparticles is directly observed during their reduction, and Pt greatly lowers the reduction temperature. For the first time, the initial reduction of Co3 O4 with and without Pt is studied at the nanoscale. The initial reduction of Co3 O4 changes from surface to interface between Co3 O4 and SiO2 . Small Pt nanoparticles located at the interface between Co3 O4 and SiO2 promote the reduction of Co3 O4 by the detachment of Co3 O4 /CoO from SiO2 . After reduction, the Pt and part of the Co form an alloy with Pt well dispersed. This study for the first time unravels the effects of Pt location and distribution on the reduction of Co3 O4 nanoparticles, and helps to design cobalt-based catalysts with efficient use of Pt as a reduction promoter.

Natural Convection in Trapezoidal Cavity containing Hybrid Nanofluid

In this paper, a numerical study of natural convection in a trapezoidal cavity with left heated wall, right cold wall and filled with Cu – Al2 O3 and water hybrid nanofluid. The remaining walls of the cavity are kept at adiabatic. An enhancement in heat transfer is observed with the increase of three different parameters. Based upon the numerical predictions, the effect of Rayleigh number, inclination of the slopping wall, solid volume fraction of nanoparticles on flow and patterns as well tested. We found that acute slopping wall, high Rayleigh number and Cu – Al2 O3 nanoparticles with high concentration are effective to enhance the rate of heat transfer. We also developed a new correlation for the average Nusselt number as a function of the angle, effective thermal conductivity and viscosity as well as Rayleigh number.

A Flexible Tough Hydrovoltaic Coating for Wearable Sensing Electronics.

The lack of a strong binding mechanism between nanomaterials severely restricts the advantages of the evaporation-driven hydrovoltaic effect in wearable sensing electronics. It is a challenging task to observably improve the mechanical toughness and flexibility of hydrovoltaic devices to match the wearable demand without abandoning the nanostructures and surface function. Here, a flexible tough polyacrylonitrile/alumina (PAN/Al2 O3 ) hydrovoltaic coating with both good electricity generation (open-circuit voltage, Voc ≈3.18V) and sensitive ion sensing (2285VM-1 for NaCl solutions in 10-4 to 10-3 m) capabilities is developed. The porous nanostructure composed of Al2 O3 nanoparticles is firmly locked by the strong binding effect of PAN, giving a critical binding force 4 times that of Al2 O3 film to easily deal with 9.92ms-1 strong water-flow impact. Finally, skin-tight and non-contact device structures are proposed to achieve wearable multifunctional self-powered sensing directly using sweat. The flexible tough PAN/Al2 O3 hydrovoltaic coating breaks through the mechanical brittleness limitation and broadens the applications of the evaporation-induced hydrovoltaic effect in self-powered wearable sensing electronics.

A novel high activity MnXFe3−XO4 spinel catalyst for selective catalytic reduction of NO using NH3 prepared by a short process from natural minerals for low-temperature sintering flue gas: Effect of X value on catalytic mechanism

The process of smelting and purifying the catalyst precursor salt from minerals is extremely complex, which directly leads to high catalyst costs and serious secondary pollution. In order to achieve energy saving and emission reduction in the catalyst preparation process, in-situ synthesis of catalyst materials from natural minerals is a new research direction. In this study, we firstly explored the optimal X value of MnXFe3-XO4 for the NH3 selective catalytic reduction of NO (NH3-SCR) reaction, i.e., the Mn, Fe ratio, and then prepared a novel highly active mineral-based pure phase MnXFe3-XO4 spinel NH3-SCR catalyst by natural ferromanganese ore fines with iron-red fines (Fe2O3) allotment through in situ solid-phase synthesis and magnetic separation methods according to this ratio. The results show that the X value of 1.5 (Mn1.5Fe1.5O4) is the best for NH3-SCR reaction. Mn1.5Fe1.5O4 nano-particles (201 nm) has nearly 100 % NO conversion (with 5 % H2O(g)) at 125–300 °C. The combination of characterizations and density functional theory (DFT) calculation shows that the catalytic process of Eley-Rideal (E-R) dehydrogenation is enhanced at both the active site Mn site and Fe site, which is a key factor in the acceleration of the NH3-SCR reaction with increasing X value at the MnXFe3-XO4 surface.

Co3 O4 Supported on β-Mo2 C with Different Interfaces for Electrocatalytic Oxygen Evolution Reaction.

Interface engineering is an effective strategy for improving the activity of catalysts in electrocatalytic oxygen evolution reaction (OER). Herein, Co3 O4 supported on β-Mo2 C with different interfaces were investigated for electrocatalytic OER. The morphological diversity of β-Mo2 C supports allowed different Co3 O4 -Mo2 C interactions. Various techniques characterized the composition and microstructure of the interface in the composites. Due to the strong interaction between Co3 O4 nanoparticles and β-Mo2 C nanobelts with opposing surface potentials, compact interface was observed between Co3 O4 active species and β-Mo2 C nanobelt support. The compact interface enhanced the conductivity of the material and also regulated the interfacial electron redistribution of Mo and Co atoms, promoting the charge transfer process during OER. In addition, the surface loading of Co3 O4 can effectively improve the hydrophilicity of the surface. β-Mo2 C has the capability in dissociating H2 O molecules. Thus, an example has been carefully demonstrated for interface engineering in electrocatalytic OER.

Superoxide Dismutase-Like Regulated Fe/Ppa@PDA/B for Synergistically Targeting Ferroptosis/Apoptosis to Enhance Anti-Tumor Efficacy.

The cell apoptosis pathway of sonodynamic therapy (SDT) is usually blocked, resulting in limited therapeutic efficacy, therefore, the development of new methods for sensitizing targeted ferroptosis and promoting apoptosis is of great significance to improve the anti-tumor efficacy of SDT. Herein, mesoporous Fe3 O4 nanoparticles (NPs) are synthesized for loading pyropheophorbide-a (ppa), surface-coated by polydopamine (PDA) and further anchored with tumor-targeting moieties of biotin to obtain Fe/ppa@PDA/B NPs. Fe/ppa@PDA/B displayes pH/ultrasound (US) responsive release properties, and magnetic resonance imaging (MRI) functions. Moreover, Fe3 O4 NPs of Fe/ppa@PDA/B as the Fe source for ferroptosis, enhances ferroptosis sensitivity by consuming glutathione (GSH) and producing hydroxyl radical (OH). The quinone groups of PDA layer on Fe/ppa@PDA/B own free electrons, which led to effective superoxide dismutase (SOD) action through superoxide anion (O2 - ) disproportionation to hydrogen peroxide (H2 O2 ) and oxygen (O2 ), thus, overcame hypoxia of SDT and promoted ·OH generation by Fe ions under US trigger, synergistically improves ferroptosis and apoptosis to enhance the anti-tumor efficacy of SDT both in vitro and in vivo. The anti-tumor strategy of synergistic apoptosis and ferroptosis induce by GSH depletion and self-sufficient O2 regulated by SOD provides a new idea for enhancing SDT efficacy.

B2 O3 nanoparticles alleviate salt stress in maize leaf growth zones by enhancing photosynthesis and maintaining mineral and redox status.

Salt stress induces significant loss in crop yield worldwide. Although the growth-stimulating effects of micronutrient nanoparticles (NPs) application under salinity have been studied, the molecular and biochemical mechanisms underlying these effects are poorly understood. The large size of maize leaf growth zones provides an ideal model system to sample and investigate the molecular and physiological bases of growth at subzonal resolution. Using kinematic analysis, our study indicated that salinity at 150 mM inhibited maize leaf growth by decreasing cell division and expansion in the meristem and elongation zones. Consistently, salinity downregulated cell cycle gene expression (wee1, mcm4, and cyclin-B2-4). B2 O3 NP (BNP) mitigated the stress-induced growth inhibition by reducing the decrease in cell division and expansion. BNP also enhanced the photosynthesis-related parameters. Simultaneously, chlorophyll, phosphoenolpyruvate carboxylase and ribulose-1,5-bisphosphate carboxylase/oxygenase were stimulated in the mature zone. Concomitant with growth stimulation by BNP, mineral homeostasis, particularly for B and Ca, was monitored. BNP reduced oxidative stress (e.g., lessened H2 O2 generation along the leaf zones and reduced lipid peroxidation in the mature zone) induced by salinity. This resulted from better maintenance of the redox status, that is, increased the glutathione-ascorbate cycle in the meristem and elongation zones, and flavonoids and tocopherol levels in the mature zone. Our study has important implications for assessing the salinity stress impact mitigated by BNP on maize growth, providing a basis to improve the resilience of crop species under salinity stress conditions.

Effect of manganese ion doping on magnetic properties and magnetic induction heating of Zn-Al ferrite nanoparticles

Magnetic induction hyperthermia (MIH) is a new kind of cancer treatment that preferentially targets tumor cells due to their poor heat resistance. In recent years, ferrite magnetic nanoparticles with spinel structures that can self-regulate the temperature of hyperthermia have been widely used in MIH. Importantly, substituting ions with different magnetic moments in magnetic nanoparticles can effectively regulate their Curie temperature and heating efficiency. Here we investigate the influence of Mn2+ doping on the magnetic properties, Curie temperature, and the heating efficiency of hydrothermally synthesized MnxZn1-xAl0.4Fe1.6O4 (0.4 ≤ x ≤ 0.8) nanoparticles. With increasing substitution of Zn2+ content by Mn2+, the mass magnetization increases from 30.2 to 54.2 emu g−1, the Curie temperature increases from 47.5 to 257.8 ℃, and the heating efficiency (specific loss power, SLP) increases from 6.3 to 54.5 W g−1, respectively. Of note, aqueous suspensions of Mn0.5Zn0.5Al0.4Fe1.6O4 nanoparticles demonstrate self-regulated temperature hyperthermia at 45.4 ℃ in vitro with the SLP of 11.1 W g−1 under clinically safe alternating magnetic field, manifesting a combination of high heating efficiency and clinically desirable therapeutic temperature. This study provides a new class of magnetic nanoparticles potentially useful for fast and safe MIH for cancer treatment.

Facile Synthesis of Chromium-Doped Fe1.1Mn1.9O4 Nanoparticles and the Effect of Cr Content on Their Magnetic and Structural Properties.

In the present study, Fe1.1(CrxMn1-x)1.9O4 nanoparticles (0 ≤ x ≤ 0.5) were successfully synthesized by a combustion method, and the influence of Cr substitution on the structural and magnetic properties of the obtained nanoparticles was studied by various methods. The structural analysis revealed that the sample with x = 0 has a tetragonal structure, while all Cr-doped samples crystallize into a cubic structure. Additionally, the results of TEM show that doping with chromium leads to an increase in particle size. The magnetic hysteresis loops demonstrate the behavior typical for soft magnetic materials with low coercivity and remanence magnetization. The magnetic measurements revealed that the saturation magnetization of the obtained nanoparticles demonstrates a decreasing trend with increasing Cr content. The influence of chromium doping on the observation change in saturation magnetization is discussed. Based on the results of temperature-dependent magnetization measurements, it was found that the temperature of a magnetic transition in synthesized nanoparticles depends on Cr content.