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One of the few elements that can have negative health impacts in both conditions, when consumed in excess or insufficiency is fluoride. In current study, aluminium magnetite alginate composite (AMA) was fabricated and applied using batch adsorption of fluoride as well as by using statistical modelling. Heterogeneous surface as revealed from scanning electron micrograph, thermal stability shown by thermal studies, high surface area of 29.77 m 2  g -1 , pore volume 0.1987 cm 3  g -1 with mesoporous structure having average pore radius of 133 Å shown by BET analysis, fare degree of magnetization from VSM analysis were the important features of this material. Screening experiments and batch trials were carried out to obtain optimum working conditions. pH of 3.0, dosage of 50 mg, interaction period of 60 min and concentration of 50 mg L -1 depicted maximum defluoridation efficacy of about 94%. The adsorption capacity was found to be 60.08 mg g -1 in accordance with Langmuir adsorption isotherm, while pseudo second order kinetics was followed. Overall effects of various factors on sorption process were optimized using response surface methodology (RSM). Regeneration potential of AMA has been demonstrated for 10 adsorption-desorption cycles, showing more than 60% efficiency in tenth cycle. The AMA composite shows E-factor value 0.004 depicting it is sustainable in environment. In short, this novel composite showed excellent morphological, magnetic, functional properties that led to enhanced adsorption efficiency in short span of time that can be regenerated and reused in multiple cycles., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Humic substances are organic substances prevalent in various natural environments, such as wetlands, which are globally important sources of methane (CH 4 ) emissions. Extracellular electron transfer (EET)-mediated anaerobic oxidation of methane (AOM)-coupled with humic substances reduction plays an important role in the reduction of methane emissions from wetlands, where magnetite is prevalent. However, little is known about the magnetite-mediated EET mechanisms in AOM-coupled humic substances reduction. This study shows that magnetite promotes the reduction of the AOM-coupled humic substances model compound, anthraquinone-2,6-disulfonate (AQDS). 13 CH 4 labeling experiments further indicated that AOM-coupled AQDS reduction occurred, and acetate was an intermediate product of AOM. Moreover, 13 CH 3 13 COONa labeling experiments showed that AOM-generated acetate can be continuously reduced to methane in a state of dynamic equilibrium. In the presence of magnetite, the EET capacity of the microbial community increased, and Methanosarcina played a key role in the AOM-coupled AQDS reduction. Pure culture experiments showed that Methanosarcina barkeri can independently perform AOM-coupled AQDS reduction and that magnetite increased its surface protein redox activity. The metatranscriptomic results indicated that magnetite increased the expression of membrane-bound proteins involved in energy metabolism and electron transfer in M. barkeri , thereby increasing the EET capacity. This phenomenon potentially elucidates the rationale as to why magnetite promoted AOM-coupled AQDS reduction.

In recent years, stimuli-responsive drug delivery systems based on pH, particularly those developed using bio-derived nanocomposite systems, have gained significant attention. In this work, a novel magnetic carrier was designed based on biopolymeric chitosan and metal-organic framework (MOF) for pH-controlling the release of anticancer drugs. To end this, an in-situ green method was performed to form Cu-based MOF in the presence of a magnetic polysaccharide synthesized by precipitation method toward the construction of CS/Fe 3 O 4 /Cu-MOF nanocomposite. The nanocomposite was immersed in an aqueous solution of a model anticancer drug, doxorubicin (DOX), and a higher loading capacity (90.1 ± 0.5 %) was achieved. The in-vitro drug release study showed low release rates in simulated physiological environments (pH 7.4, 37 °C, lower than about 20 %), but higher release rates in tumor tissue conditions (pH 4.5, 41 °C, higher than about 60 %) over 96 h, allowing for sustained and extended delivery of DOX. Additionally, the MTT assay demonstrated that the blank and DOX-loaded CS/Fe 3 O 4 /Cu-MOF had good cytocompatibility (over 80 % cell viability) and considerable cytotoxicity (lower than 40 % at 16 μg/mL) toward breast cancer (MCF-7) cell line, respectively. These results indicated that the synthesized nanocomposite with suitable pH-sensitivity has potential as a targeted anticancer agent., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Magnetite (Fe 3 O 4 ) is extensively applied to enhance efficacy of anaerobic biological treatment systems designed for refractory wastewater. However, the interaction between magnetite, organic pollutants and microorganisms in digestion solution is constrained by magnetic attraction. To overcome this limitation and prevent magnetite aggregation, the core-shell composite materials with carbon outer layer enveloping magnetite core particles (Fe 3 O 4 @C) were developed. The impact of Fe 3 O 4 @C with varying Fe 3 O 4 mass ratios on the anaerobic methanogenesis capability in the treatment of chloramphenicol (CAP) wastewater was investigated. Experimental results demonstrated that Fe 3 O 4 @C not only enhanced chemical oxygen demand (COD) removal efficiency and biogas production by 2.42-13.18% and by 7.53%-23.25%, respectively, but also reduced the inhibition of microbial activity caused by toxic substances and the secretion of extracellular polymeric substances (EPS) by microorganisms responding to adverse environments. The reinforcing capability of Fe 3 O 4 @C increased with the rise in Fe 3 O 4 content. Furthermore, High-throughput pyrosequencing illustrated that Fe 3 O 4 @C enhanced the relative abundance of Methanobacterium, a hydrogen-utilizing methanogen capable of participating in direct interspecies electron transfer (DIET), by 5%. Metagenomic analysis indicated that Fe 3 O 4 @C improved the decomposition of complex organics into simpler compounds by elevating functional genes encoding key enzymes associated with organic matter metabolism, acetogenesis, and hydrogenophilic methanogenesis pathways. These findings suggest that Fe 3 O 4 @C have the potential to strengthen both the hydrogenophilic methanogenesis and DIET processes. This insight offers a novel perspective on the anaerobic bioaugmentation of high-concentration refractory organic wastewater., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Trace levels of biologically precipitated magnetite (Fe 3 O 4 ) nanocrystals are present in the tissues of many living organisms, including those of plants. Recent work has also shown that magnetite nanoparticles are powerful ice nucleation particles (INPs) that can initiate heterogeneous freezing in supercooled water just below the normal melting temperature. Hence there is a strong possibility that magnetite in plant tissues might be an agent responsible for triggering frost damage, even though the biological role of magnetite in plants is not understood. To test this hypothesis, we investigated supercooling and freezing mortality in cloves of garlic (Allium sativum), a species which is known to have moderate frost resistance. Using superconducting magnetometry, we detected large numbers of magnetite INPs within individual cloves. Oscillating magnetic fields designed to torque magnetite crystals in situ and disturb the ice nucleating process produced significant effects on the temperature distribution of supercooling, thereby confirming magnetite's role as an INP in vivo. However, weak oscillating fields increased the probability of freezing, whereas stronger fields decreased it, a result that predicts the presence of magnetite binding agents that are loosely attached to the ice nucleating sites on the magnetite crystals., (© 2024. The Author(s).)

Despite the growing prevalence of nanoplastics in drinking water distribution systems, the collective influence of nanoplastics and background nanoparticles on biofilm formation and microbial risks remains largely unexplored. Here, we demonstrate that nano-sized polystyrene modified with carboxyl groups (nPS) and background magnetite (nFe 3 O 4 ) nanoparticles at environmentally relevant concentrations can collectively stimulate biofilm formation and prompt antibiotic resistance. Combined exposure of nPS and nFe 3 O 4 by P. aeruginosa biofilm cells stimulated intracellular reactive oxidative species (ROS) production more significantly compared with individual exposure. The resultant upregulation of quorum sensing (QS) and c-di-GMP signaling pathways enhanced the biosynthesis of polysaccharides by 50 %- 66 % and increased biofilm biomass by 36 %- 40 % relative to unexposed control. Consistently, biofilm mechanical stability (measured as Young's modulus) increased by 7.2-9.1 folds, and chemical stress resistance (measured with chlorine disinfection) increased by 1.4-2.0 folds. For P. aeruginosa, the minimal inhibitory concentration of different antibiotics also increased by 1.1-2.5 folds after combined exposure. Moreover, at a microbial community-wide level, metagenomic analysis revealed that the combined exposure enhanced the multi-species biofilm's resistance to chlorine, enriched the opportunistic pathogenic bacteria, and promoted their virulence and antibiotic resistance. Overall, the enhanced formation of biofilms (that may harbor opportunistic pathogens) by nanoplastics and background nanoparticles is an overlooked phenomenon, which may jeopardize the microbial safety of drinking water distribution systems., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Magnetic nanoparticles offer many exciting possibilities in biomedicine, from cell imaging to cancer treatment. One of the currently researched nanoparticles are magnetosomes, magnetite nanoparticles of high chemical purity synthesized by magnetotactic bacteria. Despite their therapeutic potential, very little is known about their degradation in human cells, and even less so of their degradation within tumours. In an effort to explore the potential of magnetosomes for cancer treatment, we have explored their degradation process in a 3D human lung carcinoma model at the subcellular level and with nanometre scale resolution. We have used state of the art hard X-ray probes (nano-XANES and nano-XRF), which allow for identification of distinct iron phases in each region of the cell. Our results reveal the progression of magnetite oxidation to maghemite within magnetosomes, and the biosynthesis of magnetite and ferrihydrite by ferritin., (© 2024. The Author(s).)

Metal hexacyanoferrates (MHCF) are a class of inorganic adsorbents used for wastewater management due to the presence of interstitial sites for capturing heavy metal ions. In present work, we are reporting the synthesis of magnetic nanocomposite of Fe 3 O 4 /graphene oxide/potassium copper hexacyanoferrate via wet chemical and coprecipitation approach. Potassium copper hexacyanoferrate (KCuHCF) and Graphene oxide (GO) both are marvelous adsorbents but their nano-size becomes a major obstacle in their separation process after the adsorption of the radionuclides. Thus, our synthesized nanocomposite Fe 3 O 4 /GO/KCuHCF enhances the recovery of KCuHCF even after radioactive Cs + adsorption with adsorption capacity of 18 mg g -1 coinciding well with the Langmuir adsorption isotherm mechanism. The synthesized adsorbent is characterized thoroughly using UV-Visible spectroscopy, FT-IR, TGA, XPS, Raman spectroscopy, TEM-EDAX and XRD. This synthesized nanocomposite is used for the batch extraction of radioactive Cs + from low level radioactive waste (LLW). The extraction kinetics followed pseudo-second-order kinetics mechanism., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

In this study, a static mixer was used as an alternative to the existing flash mixing method for ballasted flocculation to assess the turbidity removal and ballasted floc formation characteristics. Synthetic magnetite exhibits excellent properties, such as high specific gravity, hydrophobicity, and wear resistance, making it a suitable ballast agent (BA). The experimental design was optimized using the response surface methodology. To evaluate turbidity removal, a model based on polyaluminum chloride dosage, BA surface charge, and pH was developed. To assess the ballasted floc characteristics, the BA dosage, BA size, and G value of the static mixer were used. During ballasted flocculation, the impact of the zeta potential of the BA was minimal. Consequently, bonding primarily resulted from the viscosity of the floc caused by physical collisions rather than electrostatic forces stemming from the BA charge. The findings of this study demonstrated promising outcomes, including potential energy savings and process streamlining, by identifying crucial design elements for implementing a static mixer in the ballasted flocculation process., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Magnetic solid-phase extraction (MSPE) technology for tetracycline (TCC) was developed by employing the novel and pre-designed Fe 3 O 4 -COOH@hydrogen-bonded organic frameworks (HOFs) adsorbents in complex food samples. The HOF shell was grown onto the Fe 3 O 4 -COOH core by in-situ self-assembled method. The excellent MSPE performances with less solvent, less adsorbent and time consumption were derived from the hydrogen bonding, π-π and hydrophobic interactions between HOF shell and TCC. Combined with HPLC analysis, Fe 3 O 4 @ HOFs adsorbent reduced matrix effects and the established MSPE-HPLC method for TCC gave the linearity of 0.001-6 μg mL -1 with the limit of detection 0.0003 μg mL -1 . The recoveries in pure milk, canned yellow peach and carrot were 82.4-103.7 %. The method provided a simple, efficient and dependable alternative to monitor trace TCC antibiotics in food or environmental samples., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Wearable sensors for sweat trace metal monitoring have the challenges of effective sweat collection and the real-time recording of detection signals. The existing detection technologies are implemented by generating enough sweat through exercise, which makes detecting trace metals in sweat cumbersome. Generally, it takes around 20 min to obtain enough sweat, resulting in dallied and prolonged detection signals that cannot reflect the endogenous fluctuations of the body. To solve these problems, we prepared a multifunctional hydrogel as an electrolyte and combined it with a flexible patch electrode to realize real-time monitoring of sweat Zn 2+ . Such hydrogel has magnetic and porous properties, and the porous structure of hydrogel enables a fast absorption of sweat, and the magnetic property of the addition of fabricated Fe 3 O 4 NPs not only improves the conductivity but also ensures the adjustable internal structures of the hydrogel. Such a sensing platform for sweat Zn 2+ monitoring shows a satisfied linear relationship in the concentration range of 0.16-16 µg/mL via differential pulsed anodic striping voltammetry (DPASV) and successfully detects the sweat Zn 2+ of four volunteers during exercise and resting, displaying a promising path for commercial application.

Significant efforts have been dedicated to creating recyclable and efficient methods for treating waste dyes, including rhodamine B (RhB). Nevertheless, challenges such as complex operational techniques, high costs, energy consumption, and inefficacy in dye removal persist. Here, the synthesis and application of TiO 2 /Fe 3 O 4 /SiO 2 for photocatalytic degradation of RhB dye pollutants have been explored. This research was initiated with magnetite (Fe 3 O 4 ) synthesis using the coprecipitation method, followed by silica (SiO 2 ) extraction from rice husk waste using the sol-gel process, and a hydrothermal method for synthesizing titanium dioxide (TiO 2 ) and TiO 2 /Fe 3 O 4 /SiO 2 nanocomposite. The crystalline structure of TiO 2 /Fe 3 O 4 /SiO 2 was obtained with Fe 3 O 4 as the core, while TiO 2 and SiO 2 as the shell. The particle size analysis showed the nanosize of TiO 2 /Fe 3 O 4 /SiO 2 (1.04 ± 0.46 nm). TiO 2 /Fe 3 O 4 /SiO 2 nanocomposite boasts a high surface area of 48.025 m 2 /g, 2.2 times higher than unmodified TiO 2 . This nanocomposite also displayed paramagnetic properties with a saturation magnetization of 9.117 emu/g, facilitating easy separation in photocatalytic applications. The photocatalytic activity of TiO 2 /Fe 3 O 4 /SiO 2 exhibited effectively degraded RhB, achieving a degradation rate of 53.58% and an excellent rate constant of 0.7303 min -1 . The RhB photodegradation in this study requires a moderate irradiation time (60 min), uses only a tiny amount of photocatalyst (100 mg), and does not need additional chemicals. Moreover, this study has another advantage of utilizing rice husk as a silica source, offering an eco-friendly and sustainable approach., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

The contamination of water sources by pharmaceutical pollutants presents significant environmental and health hazards, making the development of effective photocatalytic materials crucial for their removal. This research focuses on the synthesis of a novel Ag/CuS/Fe₃O₄ nanocomposite and its photocatalytic efficiency against tetracycline (TC) and diclofenac contaminants. The nanocomposite was created through a straightforward and scalable precipitation method, integrating silver nanoparticles (AgNPs) and copper sulfide (CuS) into a magnetite framework. Various analytical techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR),ultraviolet-visible spectrophotometry (UV-Vis) and energy-dispersive X-ray spectroscopy (EDS), were employed to characterize the structural and morphological properties of the synthesized material. The photocatalytic activity was tested by degrading tetracycline and diclofenac under visible light. Results indicated a marked improvement in the photocatalytic performance of the Ag/CuS/Fe₃O₄ nanocomposite (98%photodegradation of TC 60 ppm in 30 min) compared to both pure magnetite and CuS/Fe₃O₄. The enhanced photocatalytic efficiency is attributed to the synergistic interaction between AgNPs, CuS, and Fe 3 O 4 , which improves light absorption and charge separation, thereby increasing the generation of reactive oxygen species (ROS) and promoting the degradation of the pollutants. The rate constant k of photodegradation was about 0.1 min -1 for catalyst dosages 0.02 g. Also the effect of photocatalyst dose and concentration of TC and pH of solution was tested. The modified photocatalyst was also used for simultaneous photodegradation of TC and diclofenac successfully. This study highlights the potential of the Ag/CuS/Fe₃O₄ nanocomposite as an efficient and reusable photocatalyst for eliminating pharmaceutical pollutants from water., (© 2024. The Author(s).)

N-nitrosamines (NAs) are highly carcinogenic compounds commonly found in food, beverages, and consumer products. Due to their wide polarity range, it is challenging to find a suitable carbon adsorbent that can simultaneously adsorb and enrich both polar and nonpolar NAs with good recovery. In this study, nitrogen-doped magnetic mesoporous carbon nanospheres (M-MCN) were prepared and employed as an adsorbent for magnetic solid-phase extraction (MSPE) to extract and concentrate four NAs. The introduction of nitrogen functional groups enhanced the hydrophilicity of the carbon material, allowing M-MCN to achieve a balance between hydrophilicity and hydrophobicity, resulting in good recovery for both polar and nonpolar NAs. A method combining MSPE with gas chromatography-mass spectrometry (GC-MS) was developed for the determination of NAs in processed meat and alcoholic beverages. The method exhibited a good linear range (1-100 ng g -1 , r 2  > 0.9967) and trace-level detection (0.53-6.6 ng g -1 ). The recovery rates for the four NAs ranged between 85.7 and 110.7 %, with intra-day precision expressed as relative standard deviation (RSD) between 4.1 and 10.7 %, and inter-day precision between 4.8 and 12.9 %. The results demonstrated not only good accuracy and precision but also provided a new adsorbent for the enrichment of trace-level NAs in processed meat and alcoholic beverage samples., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Colorectal cancer represents a worldwide spread type of cancer and it is regarded as one of the leading death causes, along with lung, breast, and prostate cancers. Since conventional surgical resection and chemotherapy proved limited efficiency, the use of alternative drug delivery systems that ensure the controlled release of cytostatic agents possess immense potential for treatment. In this regard, the present study aimed to develop and evaluate the efficiency of a series of irinotecan-loaded magnetite-silica core-shell systems. The magnetite particles were obtained through a solvothermal treatment, while the silica shell was obtained through the Stöber method directly onto the surface of magnetite particles. Subsequently, the core-shell systems were physico-chemically and morpho-structurally evaluated trough X-ray diffraction (XRD) and (high-resolution) transmission electron microscopy ((HR-)TEM) equipped with a High Annular Angular Dark Field Detector (HAADF) for elemental mapping. After the irinotecan loading, the drug delivery systems were evaluated through Fourier-transform infrared spectroscopy (FT-IR), thermogravimetry and differential scanning calorimetry (TG-DSC), and UV-Vis spectrophotometry. Additionally, the Brunauer-Emmett-Teller (BET) method was employed for determining the surface area and pore volume of the systems. The biological functionality of the core-shells was investigated through the MTT assay performed on both normal and cancer cells. The results of the study confirmed the formation of highly crystalline magnetite particles comprising the core and mesoporous silica layers of sizes varying between 2 and 7 nm as the shell. Additionally, the drug loading and release was dependent on the type of the silica synthesis procedure, since the lack of hexadecyltrimethylammonium bromide (CTAB) resulted in higher drug loading but lower cumulative release. Moreover, the nanostructured systems demonstrated a targeted efficiency towards HT-29 colorectal adenocarcinoma cells, as in the case of normal L929 fibroblast cells, the cell viability was higher than for the pristine drug. In this manner, this study provides the means and procedures for developing drug delivery systems with applicability in the treatment of cancer., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: [Adrian Ionut Nicoara reports financial support and equipment, drugs, or supplies were provided by National Center for Micro and Nanomaterials. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper]., (Copyright © 2024. Published by Elsevier B.V.)

This study examined the combination of activated carbon and magnetite with calcium peroxide in enhancing the anaerobic digestion (AD) performance of food waste (FW). The individual mechanisms of these two approaches were also clarified. The results indicated that AC/CaO 2 achieved the highest specific methane yield of 434.4 mL/g VS, followed by Fe 3 O 4 /CaO 2 (416.9 mL/g VS). Both were significantly higher than other groups (control, AC, Fe 3 O 4 , and CaO 2 were 330.1, 341.4, 342.8, and 373.2 mL/g VS, respectively). Additionally, compared to Fe 3 O 4 /CaO 2 , AC/CaO 2 further increased reactive oxygen species (ROS), thereby enhancing the hydrolytic acidification process. Simultaneously, the higher ROS levels of Fe 3 O 4 /CaO 2 and AC/CaO 2 promoted the formation of microbial aggregates and established a more robust enzymatic defense system and unique damage repair strategy. The research comparatively analyzed the synergistic mechanism of iron-based and carbon-based conductive materials with CaO 2 , providing new perspectives for optimizing the AD of FW., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Rapid on-site detection of infectious diseases is considerably essential for preventing and controlling major epidemics and maintaining social and public safety. However, the complexity of the natural environment in which infectious disease pathogens exist severely disrupts the performance of on-site detection, and rapid detection can become meaningless because of the cumbersome sample pretreatment process., Result: Herein, a new detection platform based on a carbon sphere@Fe 3 O 4 micromotor (CS@Fe 3 O 4 ) in combination with a graphene field-effect transistor (GFET) was designed and used for the on-site detection of SARS-CoV-2 coronavirus pathogens. The CS@Fe 3 O 4 micromotor, surface-modified with anti-SARS-CoV-2 coronavirus antibody, could move at a velocity of 79.4 μm/s in a solution containing hydrogen peroxide (H 2 O 2 ) and exhibited capture rates of 67.9% and 36.2% for the SARS-CoV-2 pathogen in phosphate buffered saline (PBS) and soil solutions, respectively. After magnetic field separation, the captured micromotor was used for GFET detection, with detection limits of 4.6 and 15.6 ag/mL in PBS and soil solutions, respectively., Significance and Novelty: This detection platform can be employed to avoid complex sample pretreatment procedures and achieve rapid on-site detection of SARS-CoV-2 coronavirus pathogens in complex environments. This study introduces a novel approach for the on-site detection of infectious diseases., Competing Interests: Declaration of competing interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and company that could be construed as influencing the position presented in, or the review of, the manuscript entitled., (Copyright © 2024 Elsevier B.V. All rights reserved.)

V-Ti magnetite tailings (VTMTs) contain various heavy metals, such as Fe, Mn, V, Co, and Ni. The groundwater pollution caused by the tailing metal release has become a local environmental concern. Although studies have demonstrated the influence of alternate flooding and drying cycles (FDCs) on metal form and mobility in minerals, little was known about whether FDCs affect the metal release of VTMTs and the transformation of released metals. This study investigated the metal release kinetics of VTMTs and the metal transformation under FDCs in the absence and presence of acid rain (sulfuric and nitric acids) and bio-secreted organic acids (acetic, oxalic, and citric acids). The results showed that FDCs promoted metal release whether or not acids were present. The maximum released concentrations of V, Mn, Fe, Co, and Ni were as high as 78.63 mg L -1 ,1.47 mg L -1 , 67.96 μg L -1 , 1.34 mg L -1 , and 0.80 mg L -1 , respectively, under FDCs and citric acids. FDCs enhanced the tailing metal release by increasing the metal labile fraction proportion. However, the concentrations of released Fe, Mn, V, Co, and Ni all gradually decreased due to their (co-)precipitation. These precipitates conversely inhibited the subsequent mineral dissolution by covering the tailing surface. FDCs also enhanced the tailings' porosities by 2.94%-9.94%. The mineral dissolution, expansion and shrinkage, and changes in tension destroyed the tailing microstructure during FDCs. This study demonstrated the low metal pollution risk of VTMTs under FDCs, either in acid rain or bio-secreted organic acids. However, the increase in tailing porosity should be seriously considered as it would affect the tailing pond safety., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Although the promotive effect of direct interspecies electron transfer (DIET) on methane production has been well-documented, the practical applicability of DIET in different scenarios have not yet been systematically studied. This study compared the effects of magnetite-mediated DIET with conventional biogas mixing-driven interspecies hydrogen transfer (IHT) on anaerobic digestion (AD) of swine manure (SM). Compared with control, magnetite supplementation, biogas circulation, and their integration enhanced the CH 4 yield by 19.3%, 25.9%, and 26.2%, respectively. Magnetite mainly enriched DIET-related syntrophic bacteria (Anaerolineae and Synergistia) and methanogens (Methanosarcina) to accelerate acidification and establish DIET, while biogas circulation mainly enriched hydrolytic bacteria (Clostridia) and hydrogenotrophic methanogens (Methanolinea and Methanobacterium) to promote hydrolysis and accelerate IHT. Coupling magnetite addition with biogas circulation led to the enrichment of the above six microorganisms to different extents. The effectiveness of the strategies for lowering the H 2 pressure followed: magnetite + biogas circulation ≈ biogas circulation > magnetite. Under stress-free environment, the enhancement effect of magnetite-induced DIET was not even as pronounced as biogas circulation-a simple and common mixing strategy in commercial AD plants, and the promotion effect of magnetite was insignificant in the well-mixed digesters. In short, the magnetite-mediated DIET is not always effective in improving AD of SM., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Despite the increased research efforts aimed at understanding iron-based conductive materials (CMs) for facilitating chain elongation (CE) to produce medium chain fatty acids (MCFAs), the impact of these materials on microbial community functions and the adaptation mechanisms to their biotoxicity remain unclear. This study found that the supply of zero-valent iron (ZVI) and magnetite enhanced the MCFAs carbon-flow distribution by 26 % and 52 %, respectively. Metagenomic analysis revealed the upregulation of fatty acid metabolism, pyruvate metabolism and ABC transporters with ZVI and magnetite. The predominant functional microorganisms were Massilibacterium and Tidjanibacter with ZVI, and were Petrimonas and Candidatus_Microthrix with magnetite. Furthermore, it was demonstrated that CE microorganisms respond and adapt to the biotoxicity of iron-based CMs by adjusting Two-component system and Quorum sensing for the first time. In summary, this study provided a new deep-insight on the feedback mechanisms of CE microorganisms on iron-based CMs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

A novel immobilized chitosanase was developed and utilized to produce chitosan oligosaccharides (COSs) via chitosan hydrolysis. Magnetite-agar gel particles (average particle diameter: 338 μm) were prepared by emulsifying an aqueous agar solution dispersing 200-nm magnetite particles with isooctane containing an emulsifier at 80 °C, followed by cooling the emulsified mixture. The chitosanase from Bacillus pumilus was immobilized on the magnetite-agar gel particles chemically activated by introducing glyoxyl groups with high immobilization yields (>80%), and the observed specific activity of the immobilized chitosanase was 16% of that of the free enzyme. This immobilized chitosanase could be rapidly recovered from aqueous solutions by applying magnetic force. The thermal stability of the immobilized chitosanase improved remarkably compared with that of free chitosanase: the deactivation rate constants at 35 °C of the free and immobilized enzymes were 8.1 × 10 -5 and 3.9 × 10 -8 s -1 , respectively. This immobilized chitosanase could be reused for chitosan hydrolysis at 75 °C and pH 5.6, and 80% of its initial activity was maintained even after 10 cycles of use. COSs with a degree of polymerization (DP) of 2-7 were obtained using this immobilized chitosanase, and the product content of physiologically active COSs (DP ≥ 5) reached approximately 50%., Competing Interests: Declaration of interest This research did not receive any specific grants from funding agencies in the public, commercial, or not-for-profit sectors., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Magnetomicelles were produced by the self-assembly of magnetite iron oxide nanoflowers and the amphiphilic poly(styrene)- b -poly(acrylic acid) block copolymer to deliver a multifunctional theranostic agent. Their bioprocessing by cancer cells was investigated in a three-dimensional spheroid model over a 13-day period and compared with nonencapsulated magnetic nanoflowers. A degradation process was identified and monitored at various scales, exploiting different physicochemical fingerprints. At a collective level, measurements were conducted using magnetic, photothermal, and magnetic resonance imaging techniques. At the nanoscale, transmission electron microscopy was employed to identify the morphological integrity of the structures, and X-ray absorption spectroscopy was used to analyze the degradation at the crystalline phase and chemical levels. All of these measurements converge to demonstrate that the encapsulation of magnetic nanoparticles in micelles effectively mitigates their degradation compared to individual nonencapsulated magnetic nanoflowers. This protective effect consequently resulted in better maintenance of their therapeutic photothermal potential. The structural degradation of magnetomicelles occurred through the formation of an oxidized iron phase in ferritin from the magnetic nanoparticles, leaving behind empty spherical polymeric ghost shells. These results underscore the significance of encapsulation of iron oxides in micelles in preserving nanomaterial integrity and regulating degradation, even under challenging physicochemical conditions within cancer cells.

Myeloid leukemia is a chronic cancer, which associated with abnormal BCR-ABL tyrosine kinase activity. Imatinib (IMB) acts as a tyrosine kinase inhibitor and averts tumor growth in cancer cells by controlling cell division, so it is urgent to develop an effective assay to detect and monitor its IMB concentration. Therefore, an innovative fluorescent biomimetic sensor is a promising sensing material that constructed for the efficient recognition of IMB and displays excellent selectivity and sensitivity stemming from molecularly imprinted polymer@Fe 3 O 4 (MIP@Fe 3 O 4 ). The detection strategy depends on the recognition of IMB molecules at the imprinted sites in the presence of coexisting molecules, which are then transferred to the fluorescence signal. The synthesized MIP@Fe 3 O 4 was characterized using Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Furthermore, computational studies of the band gap (E HOMO -E LUMO ) of the monomers, IMB, and their complexes were performed. These results confirmed that the copolymer is the most appropriate and has high stability (Binding energy; 0.004 x 10 -19 KJ) and low reactivity. A comprehensive linear response over IMB concentrations from 5 × 10 -6 mol/L to 8 × 10 -4 mol/L with a low detection limit of 9.3 × 10 -7 mol/L was achieved. Furthermore, the proposed technique displayed long-term stability (over 2 months), high intermediate precision (RSD<2.1 %), good reproducibility (RSD <1.9 %), and outstanding selectivity toward IMB over analogous molecules with similar chemical and spatial structure (no interference by 100 to 150-fold of the competitors). Owing to these merits, the proposed fluorescence sensor was utilized to detect IMB in drug tablets and human plasma, and satisfactory results (99.3-100.4 %) were obtained. Thus, the synthesized fluorescence sensor is a promising platform for IMB sensing in various applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The OH production by adding magnetite (MGT) alone has been reported in composting. However, the potential of nitrilotriacetic acid (NTA) addition for magnetite-amended sludge composting remained unclear. Three treatments with different addition [control check (CK); T1: 5 % MGT; T2: 5 % MGT + 5 % NTA] were investigated to characterize hydroxyl radical, humification and bacterial community response. The NTA addition manifested the best performance, with the peak OH content increase by 52 % through facilitating the cycle of Fe(Ⅱ)/Fe(Ⅲ). It led to the highest organic matters degradation (22.3 %) and humic acids content (36.1 g/kg). Furthermore, NTA addition altered bacterial community response, promoting relative abundances of iron-redox related genera, and amino acid metabolism but decreasing carbohydrate metabolism. Structural equation model indicated that temperature and Streptomyces were the primary factors affecting OH content. The study suggests that utilizing chelators is a promising strategy to strengthen humification in sewage sludge composting with adding iron-containing minerals., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Cancer, the leading cause of death worldwide, has witnessed significant advancements in treatment through targeted therapies. Among the proto-oncogenes prevalent in human cancers, KRAS stands out, and recent research has focused on long noncoding RNAs (lncRNAs) as regulators of miRNAs targeting the KRAS oncogene. This study specifically explores lncRNAs involved in the KRAS pathway in colorectal cancer (CRC). To investigate this, researchers employed iron oxide nanoparticles coated with glucose and conjugated with Oleuropein (Fe 3 O 4 @Glu-Oleuropein NPs) to evaluate their impact on candidate lncRNAs associated with KRAS pathway deregulation. The study utilized TCGA data to identify genes affected by KRAS mutation and lncRNAs linked to KRAS in CRC. Enrichr and MsigDB databases helped identify relevant pathways. Genes with a correlation coefficient above 0.5 and a P-value less than 0.01 with candidate lncRNAs were selected. MTT and flow cytometry assays determined the anti-proliferative and apoptotic effects of Fe 3 O 4 @Glu-Oleuropein NPs on CRC cells (SW480) and normal cells (HEK293). The findings showed that increased expression of FEZF1-AS1, GAS6-AS1, and LINC00920 correlated with mutated KRAS, and co-expressed genes were significantly involved in hypoxia, KRAS signaling, DNA repair, and IL-2/STAT5 signaling pathways. Fe 3 O 4 @Glu-Oleuropein NPs exhibited higher toxicity toward cancer cells, with IC50 values of 92 μg/ml for SW480 and 281 μg/ml for HEK293. Flow cytometry analysis revealed a substantial increase in necrotic and apoptotic cells when treated with Fe 3 O 4 @Glu-Oleuropein, along with down-regulation of GAS6-AS1, LINC00920, and FEZF1-AS1 lncRNAs in treated cells. In conclusion, this study highlights the therapeutic potential of Fe 3 O 4 @Glu-Oleuropein on colon cancer cells in vitro. The identification of lncRNAs involved in the KRAS pathway provides insights into the underlying mechanisms and offers avenues for further research in targeted cancer therapies., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Despite benefits such as lower water and working volume requirements, thermophilic high solids anaerobic digestion (THSAD) often fails due to the rapid build-up of volatile fatty acids (VFAs) and the associated drop in pH. Use of conductive materials (CM) can promote THSAD through stimulation of direct interspecies electron transfer (DIET), while the need for their constant dosing due to poor separation from effluent impairs economic feasibility. This study used an approach of spatially separating magnetite and granular activated carbon (GAC) from the organic fraction of municipal solid waste (OFMSW) in a single reactor for THSAD. GAC and magnetite addition could both mitigate the severe inhibition of methanogenesis after VFAs build-up to ∼28-30 g/L, while negligible methane production was observed in the control group. The highest methane yield (286 mL CH 4 /g volatile solids (VS)) was achieved in magnetite-added reactors, while the highest maximum CH 4 production rates (26.38 mL CH 4 /g VS/d) and lowest lag-phase (2.83 days) were obtained in GAC-added reactors. The enrichment of GAC and magnetite biofilms with various syntrophic and potentially electroactive microbial groups (Ruminiclostridium 1, Clostridia MBA03, Defluviitoga, Lentimicrobiaceae) in different relative abundances indicates the existence of specific preferences of these groups for the nature of CM. According to predicted basic metabolic functions, CM can enhance cellular processes and signals, lipid transport and metabolism, and methane metabolism, resulting in improved methane production. Rearrangement of metabolic pathways, formation of pili-like structures, enrichment of biofilms with electroactive groups and a significant improvement in THSAD performance was attributed to the enhancement of the DIET pathway. Promising results obtained in this work due to the spatial separation of the bulk OFMSW and CM can be useful for modeling larger-scale THSAD systems with better recovery of CM and cost-effectiveness., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The enumeration of circulating tumor cells (CTCs) in peripheral blood plays a crucial role in the early diagnosis, recurrence monitoring, and prognosis assessment of cancer patients. There is a compelling need to develop an efficient technique for the capture and identification of these rare CTCs. However, the exclusive reliance on a single criterion, such as the epithelial cell adhesion molecule (EpCAM) antibody or aptamer, for the specific recognition of epithelial CTCs is not universally suitable for clinical applications, as it usually falls short in identifying EpCAM-negative CTCs. To address this limitation, we propose a straightforward and cost-effective method involving triplex fluorescently labelled aptamers (FAM-EpCAM, Cy5-PTK7, and Texas Red-CSV) to modify Fe 3 O 4 -loaded dendritic SiO 2 nanocomposite (dmSiO 2 @Fe 3 O 4 /Apt). This multi-recognition-based strategy not only enhanced the efficiency in capturing heterogeneous CTCs, but also facilitated the rapid and accurate identification of CTCs. The capture efficiency of heterogenous CTCs reached up to 93.33%, with a detection limit as low as 5 cells/mL. Notably, the developed dmSiO 2 @Fe 3 O 4 /Apt nanoprobe enabled the swift identification of captured cells in just 30 min, relying solely on the fluorescently modified aptamers, which reduced the identification time by approximately 90% compared with the conventional immunocytochemistry (ICC) technique. Finally, these nanoprobe characteristics were validated using blood samples from patients with various types of cancers., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Background: Nanozymes, a new class of nanomaterials, have emerged as promising substitutes for enzymes in biosensor design due to their exceptional stability, affordability, and ready availability. While nanozymes address many limitations of natural enzymes, they still face challenges, particularly in achieving the catalytic activity levels of their natural counterparts. This indicates the need for enhancing the sensitivity of biosensors based on nanozymes. The catalytic activity of nanozyme can be significantly improved by regulating its size, morphology, and surface composition of nanomaterial., Results: In this work, a kind of hollow core-shell structure was designed to enhance the catalytic activity of nanozymes. The hollow core-shell structure material consists of a nanozymes core layer, a hollow layer, and a MOF shell layer. Taking the classic peroxidase like Fe 3 O 4 as an example, the development of a novel nanozyme@MOF, specifically p-Fe 3 O 4 @PDA@ZIF-67, is detailed, showcasing its application in enhancing the sensitivity of sensors based on Fe 3 O 4 nanozymes. This innovative nanocomposite, featuring that MOF layer was designed to adsorb the signal molecules of the sensor to improve the utilization rate of reactive oxygen species generated by the nanozymes catalyzed reactions and the hollow layer was designed to prevent the active sites of nanozymes from being cover by the MOF layer. The manuscript emphasizes the nanocomposite's remarkable sensitivity in detecting hydrogen peroxide (H 2 O 2 ), coupled with high specificity and reproducibility, even in complex environments like milk samples., Significance and Novelty: This work firstly proposed and proved that Fe 3 O 4 nanozyme@MOF with hollow layer structure was designed to improve the catalytic activity of the Fe 3 O 4 nanozyme and the sensitivity of the sensors based on Fe 3 O 4 nanozyme. This research marks a significant advancement in nanozyme technology, demonstrating the potential of structural innovation in creating high-performance, sensitive, and stable biosensors for various applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Herein, we constructed the branch-shaped SiO 2 /nano GO (nGO)/Fe 3 O 4 /selenium quantum dots (QDs) (SeQDs) nanoparticles (SGF/SeQDs) embodying magnetism, fluorescence, and microwave stimulus response properties to enhance the performance of releasing drugs. The SGF/SeQDs composite was characterized by technologies including powder X-ray diffraction, transmission electron microscopy, infrared spectroscopy, etc. In the nanoparticles, the branch-shaped SiO 2 provides a large specific surface area, nGO as the dielectric loss-style material promotes microwave-absorbing performance, and the Fe 3 O 4 serves as a magnetic targeting agent and microwave absorber. Integrating nGO and Fe 3 O 4 could further strengthen the microwave absorption of the entire composite; selenium features both fluorescence and anticancer effects. The synthesized nanoparticles as carriers exhibited a branch-like mesoporous sphere of ∼260 nm, a specific surface area of 258.57 m 2 g -1 , a saturation magnetization of 24.59 emu g -1 , and good microwave thermal conversion performance that the temperature was elevated from 25 to 70 °C under microwave irradiation. These physical characteristics, including large pore volume (5.30 nm), high specific surface area, and fibrous morphology, are in favor of loading drugs. Meanwhile, the cumulative etoposide (VP16) loading rate of the nanoparticles reached to 21 wt % after 360 min. The noncovalent interaction between the VP16 and SGF/SeQDs was mainly the hydrogen-bonding effect during the loading process. Furthermore, the drug release rates at 180 min were up to 81.46, 61.92, and 56.84 wt % at pH 4, 5, and 7, respectively. At 25, 37, and 50 °C, the rates of drug release reach 25.40, 56.84, and 65.32 wt %, respectively. After microwave stimulation at pH 7, the rate of releasing drug increased distinctly from 56.84 to 71.74 wt % compared to that of nonmicrowave irradiation. Cytotoxicity tests manifested that the carrier had good biocompatibility. Therefore, the nanoparticles are looking forward to paving one platform for further applications in biomedicine and drug delivery systems.

Magnetite mining is a significant contributor to land deterioration as well as HM-based soil contamination. The characteristics of magnetite mine tailing were examined in the present study, in addition to the positive and sustainable restoration strategy with Bougainvillaea glabra under the influence of Thiobacillus ferroxidance. The traits of test soil analysis findings demonstrated that the majority of the parameters exceeded the allowable limits (For instance: HMs such as Cr, Cu, Zn, Pb, Fe, and Co were found to be 208 ± 2.3, 131.43 ± 1.6, 185.41 ± 3.3, 312 ± 5.11, 956 ± 5.3, and 26.89 ± 2.43 mg kg -1 respectively). T. ferroxidance exhibited impressive HMs tolerance for as much as 800 g mL -1 concentrations of Cr, Cu, Zn, Pb, Fe, and Co. To prevent HMs toxic effects, the HMs contents in test soil were decreased by diluting with normal soil in the ratios of Ex-3 and Ex-2. A typical greenhouse study was carried out to assess the phytoremediation ability of B. glabra across six setups for experiments (Ex-1 to Ex-6). According to the findings of this research, the HMs tolerant T. ferroxidance from Ex-3 and Ex-2 had an outstanding impact on the growth, biomolecules level (such as chlorophylls: 65.84 & 41.1 mg g -1 , proteins: 165.1 & 151.1 mg g -1 , as well as carbohydrates: 227.4 & 159.3 mg g -1 ) as well as phytoremediation potential of B. glabra on magnetite mine soil. These findings indicated that a mixture of B. glabra as well as T. ferroxidance might serve as a valuable sustainable agent for removing HMs from contaminated soil., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Magnetotactic bacteria produce chains of nanoscopic iron minerals used for navigation, which can be preserved over geological timescales in the form of magnetofossils. Micrometer-sized magnetite crystals with unusual shapes suggesting a biologically controlled mineralization have been found in the geological record and termed giant magnetofossils. The biological origin and function of giant magnetofossils remains unclear, due to the lack of modern analogues to giant magnetofossils. Using distinctive Ptychographic nanotomography data of Precambrian (1.88 Ga) rocks, we recovered the morphology of micrometric cuboid grains of iron oxides embedded in an organic filamentous fossil to construct synthetic magnetosomes. Their morphology is different from that of previously found giant magnetofossils, but their occurrence in filamentous microfossils and micromagnetic simulations support the hypothesis that they could have functioned as a navigation aid, akin to modern magnetosomes., Competing Interests: Competing interests statement:The authors declare no competing interest.

1,2,3-Trichloropropane (TCP) is an emerging groundwater pollutant, but there is a lack of reported studies on the abiotic natural attenuation of TCP by iron minerals. Furthermore, perturbation by O 2 is common in the shallow subsurface by both natural and artificial processes. In this study, natural magnetite was selected as the reactive iron mineral to investigate its role in the degradation of TCP under O 2 perturbation. The results indicated that the mineral structural Fe(II) on magnetite reacted with dissolved oxygen to generate O 2 - · and HO·. Both O 2 - · and HO· contributed to TCP degradation, with O 2 - · playing a more important role. After 56 days of reaction, 66.7% of TCP was completely dechlorinated. This study revealed that higher magnetite concentrations, smaller magnetite particle sizes, and lower initial TCP concentrations favored TCP degradation. The presence of <10 mg/L natural organic matter (NOM) did not affect TCP degradation. These findings significantly advance our understanding of the abiotic natural attenuation mechanisms facilitated by iron minerals under O 2 perturbation, providing crucial insights for the study of natural attenuation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Discovery of nitrate/nitrite-dependent anaerobic methane oxidation (DAMO) challenges the conventional biological treatment processes, since it provides a possibility of simultaneously mitigating dissolved methane emissions from anaerobic effluents and reducing additional carbon sources for denitrification. Due to the slow growth of specialized DAMO microbes, this possibility has been just practiced with biofilms in membrane biofilm reactors or granular sludge in membrane bioreactors. In this study, simultaneous elimination of dissolved methane from anaerobic effluents and nitrate/nitrite reduction was achieved in a conventional anoxic reactor with magnetite. Calculations of electron flow balance showed that, with magnetite the eliminated dissolved methane was almost entirely used for nitrate/nitrite reduction, while without magnetite approximately 52 % of eliminated dissolved methane was converted to unknown organics. Metagenomic sequencing showed that, when dissolved methane served as an electron donor, the abundance of genes for reverse methanogenesis and denitrification dramatically increased, indicating that anaerobic oxidation of methane (AOM) coupled to nitrate/nitrite reduction occurred. Magnetite increased the abundance of genes encoding the key enzymes involved in whole reverse methanogenesis and Nir and Nor involved in denitrification, compared to that without magnetite. Analysis of microbial communities showed that, AOM coupled to nitrate/nitrite reduction was proceeded by syntrophic consortia comprised of methane oxidizers, Methanolinea and Methanobacterium, and nitrate/nitrite reducers, Armatimonadetes&#95;gp5 and Thauera. With magnetite syntrophic consortia exchanged electrons more effectively than that without magnetite, further supporting the microbial growth., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

The efficiency of the Fenton reaction is markedly contingent upon the operational pH related to iron solubility. Therefore, a heterogeneous Fenton reaction has been developed to function at neutral pH. In the present study, the Bio-Fenton reaction was carried out using magnetite (Fe(II)Fe(III) 2 O 4 ) and H 2 O 2 generated by a newly isolated H 2 O 2 -producing bacterium, Desemzia sp. strain C1 at pH 6.8 to degrade chloroacetanilide herbicides. The optimal conditions for an efficient Bio-Fenton reaction were 10 mM of lactate, 0.5% (w/v) of magnetite, and resting-cells (O.D. 600  = 1) of strain C1. During the Bio-Fenton reaction, 1.8-2.0 mM of H 2 O 2 was generated by strain C1 and promptly consumed by the Fenton reaction with magnetite, maintaining stable pH conditions. Approximately, 40-50% of the herbicides underwent oxidation through non-specific reactions of •OH, leading to dealkylation, dechlorination, and hydroxylation via hydrogen atom abstraction. These findings will contribute to advancing the Bio-Fenton system for non-specific oxidative degradation of diverse organic pollutants under in-situ environmental conditions with bacteria producing high amount of H 2 O 2 and magnetite under a neutral pH condition., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The detection of magnetic fields by animals is known as magnetoreception. The ferromagnetic hypothesis explains magnetoreception assuming that magnetic nanoparticles are used as magnetic field transducers. Magnetite nanoparticles in the abdomen of Apis mellifera honeybees have been proposed in the literature as the magnetic field transducer. However, studies with ants and stingless bees have shown that the whole body of the insect contain magnetic material, and that the largest magnetization is in the antennae. The aim of the present study is to investigate the magnetization of all the body parts of honeybees as has been done with ants and stingless bees. To do that, the head without antennae, antennae, thorax, and abdomen obtained from Apis mellifera honeybees were analyzed using magnetometry and Ferromagnetic Resonance (FMR) techniques. The magnetometry and FMR measurements show the presence of magnetic material in all honeybee body parts. Our results present evidence of the presence of biomineralized magnetite nanoparticles in the honeybee abdomen and, for the first time, magnetite in the antennae. FMR measurements permit to identify the magnetite in the abdomen as biomineralized. As behavioral experiments reported in the literature have shown that the abdomen is involved in magnetoreception, new experimental approaches must be done to confirm or discard the involvement of the antennae in magnetoreception., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Micro/nanomotors (MNMs) are miniature devices that can generate energy through chemical reactions or physical processes, utilizing this energy for movement. By virtue of their small size, self-propulsion, precise positioning within a small range, and ability to access microenvironments, MNMs have been applied in various fields including sensing, biomedical applications, and pollutant adsorption. However, the development of food-grade MNMs and their application in food delivery systems have been scarcely reported. Currently, there are various issues with the decomposition, oxidation, or inability to maintain the activity of some nutrients or bioactive substances, such as the limited application of curcumin (Cur) in food. Compared to traditional delivery systems, MNMs can adjust the transport speed and direction as needed, effectively protecting bioactive substances during delivery and achieving efficient transportation. Therefore, this study utilizes polysaccharides as the substrate, employing a simple, rapid, and pollution-free template method to prepare polysaccharide-based microtubes (PMTs) and polysaccharide-based micro/nanomotors (PMNMs). PMNMs can achieve multifunctional propulsion by modifying ferrosoferric oxide (Fe 3 O 4 ), platinum (Pt), and glucose oxidase (GOx). Fe-PMNMs and Pt-PMNMs exhibit excellent photothermal conversion performance, showing promise for applications in photothermal therapy. Moreover, PMNMs can effectively deliver curcumin, achieving the effective delivery of nutrients and exerting the anti-inflammatory performance of the system.

Cancer stands as one of the most impactful illnesses in the modern world, primarily owing to its lethal consequences. The fundamental concern in this context likely stems from delayed diagnoses in patients. Hence, detecting various forms of cancer is imperative. A formidable challenge in cancer research has been the diagnosis and treatment of this disease. Early cancer diagnosis is crucial, as it significantly influences subsequent therapeutic steps. Despite substantial scientific efforts, accurately and swiftly diagnosing cancer remains a formidable challenge. It is well known that the field of cancer diagnosis has effectively included electrochemical approaches. Combining the remarkable selectivity of biosensing components-such as aptamers, antibodies, or nucleic acids-with electrochemical sensor systems has shown positive outcomes. In this study, we adapt a novel electrochemical biosensor for cancer detection. This biosensor, based on a glassy carbon electrode, incorporates a nanocomposite of reduced graphene oxide/Fe 3 O 4 /Nafion/polyaniline. We elucidated the modification process using SEM, TEM, FTIR, RAMAN, VSM, and electrochemical methods. To optimize the experimental conditions and monitor the immobilization processes, electrochemical techniques such as CV, EIS, and SWV were employed. The calibration graph has a linear range of 10 2 -10 6  cells mL -1 , with a detection limit of 5 cells mL -1 ., (© 2024. The Author(s).)

The misuse and overuse of chloramphenicol poses severe threats to food safety and human health. In this work, we developed a magnetic solid-phase extraction (MSPE) pretreatment material coated with a multilayered metal-organic framework (MOF), Fe 3 O 4 @ (ZIF-8) 3 , for the separation and enrichment of chloramphenicol from fish. Furthermore, we designed an artificial-intelligence-enhanced single microsphere immunosensor. The inherent ultra-high porosity of the MOF and the multilayer assembly strategy allowed for efficient chloramphenicol enrichment (4.51 mg/g within 20 min). Notably, Fe 3 O 4 @ (ZIF-8) 3 exhibits a 39.20% increase in adsorption capacity compared to Fe 3 O 4 @ZIF-8. Leveraging the remarkable decoding abilities of artificial intelligence, we achieved the highly sensitive detection of chloramphenicol using a straightforward procedure without the need for specialized equipment, obtaining a notably low detection limit of 46.42 pM. Furthermore, the assay was successfully employed to detect chloramphenicol in fish samples with high accuracy. The developed immunosensor offers a robust point-of-care testing tool for safeguarding food safety and public health., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Nowadays, NOR-containing wastewater has placed huge pressure on global ecology. In this study, a chemically-modified chitosan-based polymer was cross-linked with magnetite to prepare a novel magnetic composite adsorbent named Fe 3 O 4 /CS-P(AM-SSS) for norfloxacin (NOR) removal. The preparation conditions were optimized by single factor experiments and response surface methodology. A series of characterization analyses were carried out on the morphology, structure, and properties of Fe 3 O 4 /CS-P(AM-SSS), verifying that Fe 3 O 4 /CS-P(AM-SSS) was successfully prepared. Batch adsorption experiments showed that NOR was efficiently removed by Fe 3 O 4 /CS-P(AM-SSS), with a broad pH applicability of 3-10, short adsorption equilibrium time of 60 min, maximum adsorption capacity of 268.79 mg/g, and high regeneration rate of 86% after eight adsorption-desorption cycles. Due to the three-dimensional network structure and abundant functional groups provided by modified chitosan polymer, the superior adsorption capability of Fe 3 O 4 /CS-P(AM-SSS) was achieved through electrostatic interaction, π-π stacking, hydrophobic interaction, and hydrogen bonding. Adsorption process was exothermic and well fitted by the pseudo-second-order kinetic model and the Langmuir isothermal model. The presence of cations had a slight inhibitory effect on NOR adsorption, while humic acid nearly had no effect. In model swine wastewater, 90.3% NOR was removed by Fe 3 O 4 /CS-P(AM-SSS). Therefore, with these superior characteristics, Fe 3 O 4 /CS-P(AM-SSS) was expected to be an ideal material for treating NOR-containing wastewater in the future., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

This study aims to evaluate the feasibility of an innovative reusable adsorbent through adsorption-degradation sequence for antibiotic removal from water. The magnetite/mesoporous carbon adsorbent was prepared using a two-step method of (i) in situ impregnation of magnetite precursor during resorcinol formaldehyde polymerization and (ii) pyrolysis at elevated temperature (800 °C). XRD spectra confirmed that magnetite (Fe 3 O 4 ) was the only iron oxide species present in the adsorbent, and thermogravimetric analysis revealed that its content was 10 wt%. Nitrogen sorption analysis showed that Fe 3 O 4 /carbon features a high fraction of mesopores (> 80 vol.%) and a remarkable specific surface area value (246 m 2  g -1 ), outstanding properties for water treatment. The performance of the adsorbent was examined in the uptake of three relevant antibiotics. The maximum adsorption uptakes were ca. 76 mg g -1 , ca. 70 mg g -1 , and ca. 44 mg g -1 for metronidazole, sulfamethoxazole, and ciprofloxacin, respectively. All adsorption curves were successfully fitted with Langmuir equilibrium model. The regeneration of adsorbent was carried out using Fenton oxidation under ambient conditions. After three consecutive runs of adsorption-regeneration, Fe 3 O 4 /carbon maintained its performance almost unchanged (up to 95% of its adsorption capacity), which highlights the high reusability of the adsorbent., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Biogeochemical processing of metals including the fabrication of novel nanomaterials from metal contaminated waste streams by microbial cells is an area of intense interest in the environmental sciences., Results: Here we focus on the fate of Ce during the microbial reduction of a suite of Ce-bearing ferrihydrites with between 0.2 and 4.2 mol% Ce. Cerium K-edge X-ray absorption near edge structure (XANES) analyses showed that trivalent and tetravalent cerium co-existed, with a higher proportion of tetravalent cerium observed with increasing Ce-bearing of the ferrihydrite. The subsurface metal-reducing bacterium Geobacter sulfurreducens was used to bioreduce Ce-bearing ferrihydrite, and with 0.2 mol% and 0.5 mol% Ce, an Fe(II)-bearing mineral, magnetite (Fe(II)(III) 2 O 4 ), formed alongside a small amount of goethite (FeOOH). At higher Ce-doping (1.4 mol% and 4.2 mol%) Fe(III) bioreduction was inhibited and goethite dominated the final products. During microbial Fe(III) reduction Ce was not released to solution, suggesting Ce remained associated with the Fe minerals during redox cycling, even at high Ce loadings. In addition, Fe L 2,3 X-ray magnetic circular dichroism (XMCD) analyses suggested that Ce partially incorporated into the Fe(III) crystallographic sites in the magnetite. The use of Ce-bearing biomagnetite prepared in this study was tested for hydrogen fuel cell catalyst applications. Platinum/carbon black electrodes were fabricated, containing 10% biomagnetite with 0.2 mol% Ce in the catalyst. The addition of bioreduced Ce-magnetite improved the electrode durability when compared to a normal Pt/CB catalyst., Conclusion: Different concentrations of Ce can inhibit the bioreduction of Fe(III) minerals, resulting in the formation of different bioreduction products. Bioprocessing of Fe-minerals to form Ce-containing magnetite (potentially from waste sources) offers a sustainable route to the production of fuel cell catalysts with improved performance., (© 2024. The Author(s).)

The qualitative composition and zeta potential of magnetite nanoparticles (size 4.2±1.2 nm) obtained by co-precipitation method were determined by X-ray and diffraction dynamic light scattering. The zeta potential of Fe 3 O 4 particles was -15.1±4.5 mV. The possibility of interaction of magnetite nanoparticles with human blood plasma proteins and hemoglobin as well as with erythrocyte membranes was demonstrated by spectrophotometry, electrophoresis, and fluorescence methods. No changes in the sizes of hemoglobin molecules and plasma proteins after their modification by Fe 3 O 4 particles were detected. The possibility of modifying the structural state of erythrocyte membranes in the presence of magnetite nanoparticles was demonstrated by means of fluorescent probe 1-anilinonaphthalene-8-sulfonate., (© 2024. Springer Science+Business Media, LLC, part of Springer Nature.)

The global occurrence of micropollutants in water bodies has raised concerns about potential negative effects on aquatic ecosystems and human health. EU regulations to mitigate such widespread pollution have already been implemented and are expected to become increasingly stringent in the next few years. Catalytic wet peroxide oxidation (CWPO) has proved to be a promising alternative for micropollutant removal from water, but most studies were performed in batch mode, often involving complex, expensive, and hardly recoverable catalysts, that are prone to deactivation. This work aims to demonstrate the feasibility of a fixed-bed reactor (FBR) packed with natural magnetite powder for the removal of a representative mixture of azole pesticides, recently listed in the EU Watch Lists. The performance of the system was evaluated by analyzing the impact of H 2 O 2 dose (3.6-13.4 mg L -1 ), magnetite load (2-8 g), inlet flow rate (0.25-1 mL min -1 ), and initial micropollutant concentration (100-1000 µg L -1 ) over 300 h of continuous operation. Azole pesticide conversion values above 80% were achieved under selected operating conditions (W Fe3O4  = 8 g, [H 2 O 2 ] 0  = 6.7 mg L -1 , flow rate = 0.5 mL min -1 , pH 0  = 5, T = 25 °C). Notably, the catalytic system showed a high stability upon 500 h in operation, with limited iron leaching (< 0.1 mg L -1 ). As a proof of concept, the feasibility of the system was confirmed using a real wastewater treatment plant (WWTP) effluent spiked with the mixture of azole pesticides. These results represent a clear advance for the application of CWPO as a tertiary treatment in WWTPs and open the door for the scale-up of FBR packed with natural magnetite., (© 2024. The Author(s).)

Magnetite is a reductive Fe(II)-bearing mineral, and its reduction property is considered important for degradation of contaminants in groundwater and anaerobic subsurface environments. However, the redox condition of subsurface environments frequently changes from anaerobic to aerobic owing to natural and anthropogenic disturbances, generating reactive oxygen species (ROS) from the interaction between Fe(II)-bearing minerals and O 2 . Despite this, the mechanism of ROS generation induced by magnetite under aerobic conditions is poorly understood, which may play a crucial role in As(III) oxidation. Herein, we found that magnetite could activate O 2 and induce the oxidative transformation of As(III) under aerobic conditions. As(III) oxidation was attributed to the ROS generated via structural Fe(II) within the magnetite octahedra oxygenation. The electron paramagnetic resonance and quenching tests confirmed that O 2 •- , H 2 O 2 , and •OH were produced by magnetite. Moreover, density function theory calculations combined with experiments demonstrated that O 2 •- was initially formed via single electron transfer from the structural Fe(II) to the adsorbed O 2 ; O 2 •- was then converted to •OH and H 2 O 2 via a series of free radical reactions. Among them, O 2 •- and H 2 O 2 were the primary ROS responsible for As(III) oxidation, accounting for approximately 52 % and 19 % of As(III) oxidation. Notably, As(III) oxidation mainly occurred on the magnetite surface, and As was immobilized further within the magnetite structure. This study provides solid evidence regarding the role of magnetite in determining the fate and transformation of As in redox-fluctuating subsurface environments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Although nanozymes exhibit properties superior to those of natural enzymes and conventional engineered enzymes, the development of highly specific nanozymes remains a challenge. New yolk-shell Fe 3 O 4 molecularly imprinted (MIP@void@Fe 3 O 4 ) nanozymes with peroxidase-like activity were developed by modelling the substrate channels of natural enzymes through molecular imprinting techniques and interfacial affinity modifications in this study. To establish a platform technology for the adsorption and determination of inorganic and organic contaminants, lead ion (Pb 2+ ) and diazinon (DIZ), respectively, were selected as imprinting templates, and a hollow mesoporous shell was synthesized. The as-prepared MIP@void@Fe 3 O 4 nanozymes, characterized using TEM, HRTEM, SEM, FT-IR, TGA, VSM and XPS, not only affirmed the successful fabrication of a magnetic nanoparticle with a unique hollow core-shell structure but also facilitated an exploration of the interfacial bonding mechanisms between Fe 3 O 4 and other shell layers. The enrichment of the MIP@void@Fe 3 O 4 nanozymes due to imprinting was approximately 5 times higher than the local substrate concentration and contributed to the increased activity. Based on selective and competitive recognition experiments, the synthesized nanozymes could selectively recognize organic and inorganic targets with the lowest detection limits (LOD) of 6.6 × 10 -9 ppm for Pb 2+ and 5.13 × 10 -11 M for DIZ. Therefore, the proposed biosensor is expected to be a potent tool for trace pollutant detection, which provides a rational design for more advanced and subtle methods to bridge the activity gap between natural enzymes and nanozymes.

Magnetite is a common mixed Fe(II,III) iron oxide in mineral deposits and the product of (anaerobic) iron corrosion. In various Earth systems, magnetite surfaces participate in surface-mediated redox reactions. The reactivity and redox properties of the magnetite surface depend on the surface speciation, which varies with environmental conditions. In this study, Kohn-Sham density functional theory (DFT + U method) was used to examine the stability and speciation of the prevalent magnetite crystal face {111} in a wide range of pH and E h conditions. The simulations reveal that the oxidation state and speciation of the surface depend strongly on imposed redox conditions and, in general, may differ from those of the bulk state. Corresponding predominant phase diagrams for the surface speciation and structure were calculated from first principles. Furthermore, classical molecular dynamics simulations were conducted investigating the mobility of water near the magnetite surface. The obtained knowledge of the surface structure and oxidation state of iron is essential for modeling retention of redox-sensitive nuclides.

This study investigated the role of ξ Potential on Monometallic (MM) and Bimetallic (BM) Calcium Oxide/Magnetite Iron Oxides nanoparticles to stimulate the immune response. Metallic nanoparticles (MNPs) were biosynthesis using Pseudomonas fluorescens S48. MNPs characterization was carried out by UV-Vis spectra, XRD analysis, Zeta potential and Particles size, SEM-EDS, and TEM, and the concentrations were calculated by ICP-AES. The immune system activity was measured by estimation of lymphocytes transformation, phagocytic activity. The end point was in evaluating the toxicity of Metallic NPs by comet assay. SEM-EDS and TEM micrographs showed that MM CaO and Fe 3 O 4 represent a perfect example of zero-dimensional (0-D) NPs with cubic and spherical particles in shape, while BM CaO/Fe 3 O 4 NPs appeared in the form of Core-shell structure. The variations effect of novelty MM, BM CaO/Fe 3 O 4 NPs in enhancing immune activity were based on the ξ Potential whereas negatively and positively charged. These findings demonstrate that the cationic CaO/Fe 3 O 4 NPs are inefficient in stimulating the immune system which causes a high cytotoxic effect. But the anionic CaO/Fe 3 O 4 NPs have advantages in targeting the immune system because of enhanced delivery to the cells through adsorptive endocytosis as well as the half-life clearance from the blood.

"Core/shell" nanocomposites based on magnetic magnetite (Fe 3 O 4 ) and redox-active cerium dioxide (CeO 2 ) nanoparticles (NPs) are promising in the field of biomedical interests because they can combine the ability of magnetic NPs to heat up in an alternating magnetic field (AMF) with the pronounced antioxidant activity of CeO 2 NPs. Thus, this report is devoted to Fe 3 O 4 /CeO 2 nanocomposites (NCPs) synthesized by precipitation of the computed amount of "CeO 2 -shell" on the surface of prefabricated Fe 3 O 4 NPs. The X-ray diffraction, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy data validated the formation of Fe 3 O 4 /CeO 2 "core/shell"-like NCPs, in which ultrafine CeO 2 NPs with an average size of approximately 3-3.5 nm neatly surround Fe 3 O 4 NPs. The presence of a CeO 2 "shell" significantly increased the stability of Fe 3 O 4 /CeO 2 NCPs in aqueous suspensions: Fe 3 O 4 /CeO 2 NCPs with "shell thicknesses" of 5 and 7 nm formed highly stable magnetic fluids with ζ-potential values of >+30 mV. The magnetization values of Fe 3 O 4 /CeO 2 NCPs decreased with a growing CeO 2 "shell" around the magnetic NPs; however, the resulting composites retained the ability to heat efficiently in an AMF. The presence of a CeO 2 "shell" generates a possibility to precisely regulate tuning of the maximum heating temperature of magnetic NCPs in the 42-50 °C range and stabilize it after a certain time of exposure to an AMF by changing the thickness of the "CeO 2 -shell". A great improvement was observed in both antioxidant and antiamyloidogenic activities. It was found that inhibition of insulin amyloid formation, expressed in IC 50 concentration, using NCPs with a "shell thickness" of 7 nm was approximately 10 times lower compared to that of pure CeO 2 . For these NCPs, more than 2 times higher superoxide dismutase-like activity was observed. The coupling of both Fe 3 O 4 and CeO 2 results in higher bioactivity than either of them individually, probably due to a synergistic catalytic mechanism.

Magnetotactic bacteria (MTB), which precisely bio-synthesize magnetosomes of magnetite or greigite nanoparticles, have attracted broad interdisciplinary interests in microbiology, magnetic materials, biotechnology and geobiology. Previous experimental and numerical investigations demonstrate a close link among MTB species, magnetosome crystal habits, and magnetic characteristics, but quantitative constraints are currently lacking. In this study, we build three-dimensional finite-element micromagnetic models of intact magnetosome chains in common MTB species and corresponding collapsed chains. Realistic numerical microstructures were constructed for the three typical biogenic magnetite crystal forms-cuboctahedron, prism and bullet. Our calculations reveal characteristic magnetic properties associated with specific magnetite crystal forms and MTB species. Cuboctahedron and bullet crystals show distinct low coercivity (less than 30 mT) and high coercivity (greater than 50 mT) clusters, respectively. Prismatic crystals have a broad range of hysteresis parameters that are strongly controlled by chain structure. This magnetic property clustering, combined with magnetic unmixing methods and electron microscopy observations, can fingerprint biogenic magnetite components in geological and environmental samples. The passive magnetic orientation efficiency of various magnetosome chains was calculated. Some bullet-shaped magnetosome chains have higher magnetic moments than those with cuboctahedron and prism magnetosomes, which may enable larger MTB cells to overcome viscous resistance for efficient magnetic navigation.

Bacterial magnetosomes synthesized by the magnetotactic bacterium Magnetospirillum magneticum are suitable for biomedical and biotechnological applications because of their high level of chemical purity of mineral with well-defined morphological features and a biocompatible lipid bilayer coating. However, utilizations of native magnetosomes are not sufficient for maximum effectiveness in many applications as the appropriate particle size differs. In this study, a method to control magnetosome particle size is developed for integration into targeted technological applications. The size and morphology of magnetosome crystals are highly regulated by the complex interactions of magnetosome synthesis-related genes; however, these interactions have not been fully elucidated. In contrast, previous studies have shown a positive correlation between vesicle and crystal sizes. Therefore, control of the magnetosome vesicle size is tuned by modifying the membrane lipid composition. Exogenous phospholipid synthesis pathways have been genetically introduced into M. magneticum. The experimental results show that these phospholipids altered the properties of the magnetosome membrane vesicles, which yielded larger magnetite crystal sizes. The genetic engineering approach presented in this study is shown to be useful for controlling magnetite crystal size without involving complex interactions of magnetosome synthesis-related genes., (Copyright © 2023 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)