Manganese Oxide Nanoparticles Research Articles

Preparation and Effects of Manganese Oxide Nanoparticles Against Quinolone-Resistant Bacteria Isolated from Hospital Wastewater

Background: The widespread administration of quinolones may have led to an increase in bacterial resistance development. Objective: To synthesize and characterize manganese oxide nanoparticles (MnO2NPs) and evaluate their effects on the viability and biofilm formation of quinolone-resistant gram-positive and negative pathogenic bacteria. Methods: We prepared MnO2NPs using the photo-irradiation method and recorded their characteristics using XRD, TEM, and SEM. Staphylococcus aureus, Streptococcus pneumonia, Escherichia coli, Klebsiella pneumonia, and Pseudomonas aeruginosa were collected from the wastewater of Baghdad hospitals during the period from July 3rd to July 14th, 2023. We used the VITEK2 system to confirm and identify all of the isolates. We conducted biofilm formation and antibiotic susceptibility tests using nalidixic acid, ciprofloxacin, norfloxacin, aztreonam, levofloxacin, and ofloxacin, and also detected the qnrA and qnrB genes. Finally, we evaluated the effects of the prepared nanoparticles on the viability and biofilm formation of bacterial isolates. Results: MnO2NPs characterizations showed a diffraction peak at 2θ values with 21 nm average sizes; qnrA and qnrB genes were found in three and four isolates, respectively; and significant effects of MnO2NPs against viability and biofilm formation were recorded. Conclusions: The synthesized nanoparticles have antibacterial and anti-biofilm activities against a variety of bacteria possessing qnr genes. Even multi-resistant bacterial isolates have the potential to be strong antimicrobial agents against these pathogens.

Plant-mediated synthesis of Mn3O4 nanoparticles: challenges and applications.

This review focuses on the green synthesis methods, challenges, and applications of manganese oxide (Mn3O4) nanoparticles investigated in the past five years. Mn3O4 nanoparticles offer some unique properties that are attributed in part to the presence of mixed oxidation states of manganese (i.e., +2 and +3) in the particle, which can be utilized in a wide range of redox-sensitive applications, such as in developing supercapacitive energy storage materials. In addition, the green synthesis of Mn3O4 nanoparticles through plant extracts has potential uses in sustainable nanotechnology. Various plant extract-mediated synthesis techniques for Mn3O4 nanoparticles have been investigated and presented. By comparing the size and structure of the synthesized Mn3O4 nanoparticles, we have observed a consistent pattern of obtaining spherical particles with a size ranging from 16 to 50 nm. The morphology of the generated Mn3O4 nanoparticles can be influenced by the annealing temperature and the composition of the plant extract used during the nanoparticle synthesis. Additionally, numerous applications for the greenly produced Mn3O4 nanoparticles have been demonstrated. Mn3O4 nanoparticles derived from plant extracts have been found to possess antimicrobial properties, supercapacitive and electrochemical capabilities, and excellent pollutant degradation efficiency. However, the magnetic properties of these nanoparticles synthesized by plant extracts are yet to be explored for potential biomedical applications. Finally, challenges to existing synthetic methods and future perspectives on the potential applications of these green synthesized Mn3O4 nanoparticles are highlighted.

Microstructural Characterization, Mechanical Performance, and Anti-Corrosive Response of Zinc Multifaceted Coating on Mild Steel

Zinc has attracted significant attention in research due to its cost-effective use as an electrodeposited material, effectively protecting various types of steel from corrosion and wear. However, despite its advantages, zinc has limitations in fully guarding steel against corrosion. Recent studies propose that blending zinc with other metals during the coating process can proficiently shield mild steel from deterioration. The motivation for this study stems from recognizing the restrictions of zinc electrodeposition and the limited exploration of zinc multi-facet composite coatings for mild steel. In this study, the electrodeposition technique was employed to apply a coating to mild steel using zinc and nanoparticles of calcium oxide (CaO) and manganese oxide (MnO2). The coating bath's chemical composition included mass variations of 0-12 g/L for CaO and MnO2, along with 10 g/L each of boric acid, thiourea, and Na2SO4, and 15 g/L of K2SO4 and ZnSO4. The coating process occurred over a twenty-minute period, with a pH of 4.8, voltage set at 3.2V, current density at 1 A/cm2, temperature at 47°C, and stirring rate at 200 rpm. Results obtained from the coated mild steel demonstrated that Zn-6CaO-6MnO2 exhibited the greatest coating thickness at 0.2308 mm, and it showcased impressive corrosion resistance at 2.0618 mm/year. The Zn-CaO-MnO2 coating displayed a substantial deposit of crystallites in its microstructure, assisted by the presence of manganese, contributing to a smoother surface texture.

A novel potentiometric screen-printed electrode based on crown ethers/nano manganese oxide/Nafion composite for trace level determination of copper ion in biological fluids.

Copper levels in biological fluids are associated with Wilson's, Alzheimer's, Menke's, and Parkinson's diseases, making them good biochemical markers for these diseases. This study introduces a miniaturized screen-printed electrode (SPE) for the potentiometric determination of copper(II) in some biological fluids. Manganese(III) oxide nanoparticles (Mn2O3-NPs), dispersed in Nafion, are drop-casted onto a graphite/PET substrate, serving as the ion-to-electron transducer material. The solid-contact material is then covered by a selective polyvinyl chloride (PVC) membrane incorporated with 18-crown-6 as a neutral ion carrier for the selective determination of copper(II) ions. The proposed electrode exhibits a Nernstian response with a slope of 30.2 ± 0.3mV/decade (R2 = 0.999) over the linear concentration range 5.2 × 10-9 - 6.2 × 10-3mol/l and a detection limit of 1.1 × 10-9mol/l (69.9ng/l). Short-term potential stability is evaluated using constant current chronopotentiometry (CP) and electrochemical impedance spectroscopy (EIS). A significant improvement in the electrode capacitance (91.5 μF) is displayed due to the use of Mn2O3-NPs as a solid contact. The presence of Nafion, with its high hydrophobicity properties, eliminates the formation of the thin water layer, facilitating the ion-to-electron transduction between the sensing membrane and the conducting substrate. Additionally, it enhances the adhesion of the polymeric sensing membrane to the solid-contact material, preventing membrane delamination and increasingthe electrode's lifespan. The high selectivity, sensitivity, and potential stability of the proposed miniaturized electrode suggests its use for the determination of copper(II) ions in human blood serum and milk samples. The results obtained agree fairly well with data obtained by flameless atomic absorption spectrometry.

Rutin-coated ultrasmall manganese oxide nanoparticles for targeted magnetic resonance imaging and photothermal therapy of malignant tumors

Manganese oxide nanoparticles (MONs)-based contrast agents have attracted increasing attention for magnetic resonance imaging (MRI), attributed to their good biocompatibility and advantageous paramagnetism. However, conventional MONs have poor imaging performance due to low T1 relaxivity. Additionally, their lack of tumor-targeting theranostics capabilities and complex synthesis pathways have impeded clinical applications. Rutin (Ru) is an ideal tumor-targeted ligand that targets glucose transporters (GLUTs) overexpressed in various malignant tumors, and exhibits photothermal effects upon chelation with metal ions. Herein, a series of Ru-coated MONs (Ru/MnO2) were synthesized using a straightforward, rapid one-step process. Specifically, Ru/MnO2-5, with the smallest crystal size of approximately 4 nm, exhibits the highest T1 relaxivity (33.3 mM-1s−1 at 1.5 T, surpassing prior MONs) along with notable stability, photothermal efficacy, and tumor-targeting ability. Furthermore, Ru/MnO2-5 shows promise in MRI and photothermal therapy of H22 tumors owing to its superior GLUTs-mediated tumor-targeting capability.

Magnetic Field-Optimized Paramagnetic Nanoprobe for T2/T1 Switchable Histopathological-Level MRI.

Traditional magnetic resonance imaging (MRI) contrast agents (CAs) are a type of "always on" system that accelerates proton relaxation regardless of their enrichment region. This "always on" feature leads to a decrease in signal differences between lesions and normal tissues, hampering their applications in accurate and early diagnosis. Herein, we report a strategy to fabricate glutathione (GSH)-responsive one-dimensional (1-D) manganese oxide nanoparticles (MONPs) with improved T2 relaxivities and achieve effective T2/T1 switchable MRI imaging of tumors. Compared to traditional contrast agents with high saturation magnetization to enhance T2 relaxivities, 1-D MONPs with weak Ms effectively increase the inhomogeneity of the local magnetic field and exhibit obvious T2 contrast. The inhomogeneity of the local magnetic field of 1-D MONPs is highly dependent on their number of primary particles and surface roughness according to Landau-Lifshitz-Gilbert simulations and thus eventually determines their T2 relaxivities. Furthermore, the GSH responsiveness ensures 1-D MONPs with sensitive switching from the T2 to T1 mode in vitro and subcutaneous tumors to clearly delineate the boundary of glioma and metastasis margins, achieving precise histopathological-level MRI. This study provides a strategy to improve T2 relaxivity of magnetic nanoparticles and construct switchable MRI CAs, offering high tumor-to-normal tissue contrast signal for early and accurate diagnosis.

Optical and electrochemical properties of manganese oxide (Mn3O4) nanoparticles: Investigating the influence of calcination temperature on supercapacitor performance

In this study, we investigate the influence of calcination temperature on the structural, optical, and electrochemical properties of Mn3O4 nanoparticles synthesized through a chemical co-precipitation route. Field-Emission Scanning Electron Microscopy (FESEM) images depict the formation of highly agglomerated, spherical-shaped particles. At calcination temperatures of 700 °C and 900 °C, the observation reveals the emergence of flat pellets and rod-like structures. The X-ray Diffraction (XRD) patterns confirm the presence of the Mn3O4 phase in M0 and M1 samples. However, the sample calcined at 500 °C (M3) showed a mixed phase of Mn3O4 and Mn2O3. Upon further calcination at 700 and 900 °C, this mixed phase undergoes complete transformation into the Mn2O3 phase. The change in absorption onset and photoluminescence intensity of samples is found with an increase in calcination temperature due to the crystal growth and phase modification. Furthermore, the synthesized samples are employed as electrode materials for supercapacitor applications. The sample calcined at 300 °C (M1) in three-electrode system demonstrated the specific capacitance (Csp) of 273.3 F/g at 0.5 A/g in an alkaline medium. The asymmetric cell assembled by using M1 and Hibiscus cannabinus stem-derived carbon material (HBC-900) delivered higher Csp of 205.7 F/g at 0.5 A/g. In addition, asymmetric supercapacitor device exhibited a high energy and power density of 43.1 Wh/kg and 476.2 W/kg with 82.07 % of initial Csp retention over 10,000 cycles at 10 A/g, which makes the sample M1 as the potential electrode material for supercapacitor application.

Self-Signal-Triggered Drug Delivery System for Tumor Therapy Using Cancer Cell Membrane-Coated Biocompatible Mn3O4 Nanocomposites.

In anti-cancer metastasis treatment, precise drug delivery to cancer cells remains a challenge. Innovative nanocomposites are developed to tackle these issues effectively. The approach involves the creation of manganese oxide (Mn3O4) nanoparticles (NPs) and their functionalization using trisodium citrate to yield functionalized Mn3O4 NPs (F-Mn3O4 NPs), with enhanced water solubility, stability, and biocompatibility. Subsequently, the chemotherapeutic drug doxorubicin (DOX) is encapsulated with Mn3O4 NPs, resulting in DOX/Mn3O4 NPs. To achieve cell-specific targeting, These NPs are coated with HeLa cell membranes (HCM), forming HCM/DOX/Mn3O4. For further refinement, a transferrin (Tf) receptor is integrated with cracked HCM to create Tf-HCM/DOX/Mn3O4 nanocomposites (NC) with specific cell membrane targeting capabilities. The resulting Tf-HCM/DOX/Mn3O4 NC exhibits excellent drug encapsulation efficiency (97.5%) and displays triggered drug release when exposed to NIR laser irradiation in the tumor's environment (pH 5.0 and 6.5). Furthermore, these nanocomposites show resistance to macrophage uptake and demonstrate homotypic cancer cell targeting specificity, even in the presence of other tumor cells. In vitro toxicity tests show that Tf-HCM/DOX/Mn3O4 NC achieves significant anticancer activity against HeLa and BT20 cancer cells, with percentages of 76.46% and 71.36%, respectively. These results indicate the potential of Tf-HCM/DOX/Mn3O4 NC as an effective nanoplatform for chemo-photothermal therapy.

Sulfate-functionalized ternary metal oxide/Polypyrrole nanocomposites: Synergistic enhancement in Photocatalytic, Corrosion inhibition, Magnetic, and Electrical properties

The effect of functionalization of conducting polymer/metal nanocomposites with sulfate functional groups on their physical, chemical, mechanical, optical, and electrical properties was investigated. Vanadium, Manganese, and Zinc oxide nanoparticles were prepared by the modified Sol-gel method. Conducting polymer, Polypyrrole was synthesized by the chemical oxidation method. Polypyrrole + ternary metal oxide nanocomposites were synthesized by in situ technique. The characterization of functionalized nanocomposites was carried by Raman spectroscopy, FTIR, UV–visible, magnetic, SEM, and XRD techniques. The photocatalytic, anticorrosive, magnetic, optical, and electrical properties of functionalized nanocomposites were investigated. The functionalized nanocomposites show 85 % corrosion inhibition efficiency. The functionalized nanocomposites degrade 87 % of the methyl blue dye in 120 min under UV light. The magnetic study shows the paramagnetic character of functionalized nanocomposites. The optical band gap of functionalized nanocomposites decreases to 0.5 eV, showing a high order of conductivity. The sulfate-functionalized ternary metal oxide/polypyrrole nanocomposites show synergistic enhancement in their photocatalytic, electrical, magnetic, and anticorrosive properties.

A Facile NMR Method for Pre-MRI Evaluation of Trigger-Responsive T1 Contrast Enhancement.

There is a growing interest in developing paramagnetic nanoparticles as responsive magnetic resonance imaging (MRI) contrast agents, which feature switchable T1 image contrast of water protons upon biochemical cues for better discerning diseases. However, performing an MRI is pragmatically limited by its cost and availability. Hence, a facile, routine method for measuring the T1 contrast is highly desired in early-stage development. This work presents a single-point inversion recovery (IR) nuclear magnetic resonance (NMR) method that can rapidly evaluate T1 contrast change by employing a single, optimized IR pulse sequence that minimizes water signal for "off-state" nanoparticles and allows for sensitively measuring the signal change with "switch-on" T1 contrast. Using peptide-induced liposomal gadopentetic acid (Gd3+ -DTPA) release and redox-sensitive manganese oxide (MnO2 ) nanoparticles as a demonstration of generality, this method successfully evaluates the T1 shortening of water protons caused by liposomal Gd3+ -DTPA release and Mn2+ formation from MnO2 reduction. Furthermore, the NMR measurement is highly correlated to T1 -weighted MRI scans, suggesting its feasibility to predict the MRI results at the same field strength. This NMR method can be a low-cost, time-saving alternative for pre-MRI evaluation for a diversity of responsive T1 contrast systems.

Synthesis and phase transformation study of nanostructured manganese oxide polymorphs

This paper presents the green synthesis of manganese oxide nanoparticles using olive leaf extract (OLE). The extract functions as both a reducing agent, responsible for converting manganese ions into nanoparticles, and a capping agent, aiding in stabilizing the formed nanoparticles. Our focus lies on investigating the thermal stability, phase transformation, and decomposition temperatures of different manganese oxide phases in powder form as a function of the calcination temperature. Since phase transformation depends on temperatures change at the nanoscale both thermogravimetric and differential scanning calorimetry (TGA, DSC) are used to determine the new phase transformation temperatures of the synthesized nanoparticles. Moreover, the phase structure and the exact stoichiometry are studied using ex-situ X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning/transmission electron microscopy (SEM/TEM). XRD and XPS analyses reveal the formation of amorphous MnOx at room temperature (prior to calcination), transitioning to crystalline phases (Mn2O3 and Mn3O4) post-calcination. High-resolution TEM and SEM depict the formation of nanoparticles around 15 nm in size, exhibiting different shapes. BET technique calculations give a very high specific surface area, rending these nanoparticles excellent candidates for several applications.

Biogenic synthesis of Mn3O4 NPs using Phyllanthus emblica leaf extract for electrochemical sensing of urea

Green synthesis integrates green chemistry, environmental remediation, and nanotechnology, focusing on biogenic manganese oxide nanoparticles. This method promotes advanced techniques for human health and safety by minimizing the use of chemical reagents. Herein Phyllanthus emblica leaf extract was used for producing biogenic manganese oxide nanoparticles (B-Mn3O4 NPs), which serve as a reducing, capping, and stabilizing agent in the reaction. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), FTIR, UV–visible, and energy-dispersive X-ray spectroscopy (EDS) analysis were used to investigate the structural, morphological, and spectroscopic studies of Mn3O4 NPs. These analyses confirmed the formation of a single-phase Mn3O4 tetragonal structure. The characterization results indicated that biogenic materials are heterogeneous, making them suitable candidates for electrochemical sensing of urea. This study utilizes urease enzyme to enhance the selectivity, sensitivity, and specificity of B-Mn3O4 NPs-modified electrode towards urea sensing, considering its impact on human health. The selection of the urea analyte arises from the urgent requirement to monitor environmental contamination with urea, which directly affects human health at higher concentrations. To monitor contaminated environments, this study developed ultrasensitive urea biosensors that achieved high sensitivity (2.33 µA µM−1cm−2) and selectivity with a low detection limit (0.0276 µM).

التحضير الحيوي والتشخيص ودراسات الامتزاز ومضاد الميكروبات لجسيمات اوكسيدالمنغنيز النانوية باستخدام مستخلص قشور الرمان

تضمن العمل في هذا البحث تحضير اوكسيد المنغنيز النانوي من مستخلص النباتي لقشور الرمان و كبريتات المنغنيز في وسط قاعدي وشخص بطرق مختلفة مثل ؛ FT-IR ، الأشعة فوق البنفسجية المرئية ، الفحص المجهري للقوة الذرية وحيود الأشعة السينية ، المجهر الإلكتروني النافذ ، مجهر المسح الإلكتروني ، مطيافية الأشعة السينية المشتتة للطاقة. في حيود الأشعة السينية ، تم تحديد حجم البلورة باستخدام معادلة ديباي شيرر ، والتي وُجد أنها 30.94 نانومتر. تم امتصاص أيونات المعادن التالية (II)M= Co و Ni و Cu بنجاح باستخدام MnO2 NPs ، وأظهرت النتائج أنه يمكن إزالة أيونات المعادن الثلاثة من الماء في وقت واحد, Ni (II) لديه أعلى معدل امتصاص خلال الفترة الزمنية. كانت كفاءة إزالة أيونات Co ، و Ni ، و Cu أيونات 32.79٪ ، 75.00٪ ، 30.20 ٪. تم اختبار جسيمات MnO2 النانوية ضد نوعين من البكتيريا ونوع واحد من الفطريات بثلاثة تراكيز مختلفة, تمت مقارنة النتائج مع تلك التي تم استخدام المضادات الحيوية مثل أموكسيسيلين وميترونيدازول للمقارنة النتائج.

Synthesis of Mn2O3 Nanoparticles and Determination of Its Inhibition Effect On Sera of Iraqi Patients with Diabetes Mellitus Type-2 and Diabetes Nephropathy

Manganese is essential for the synthesis of antioxidant enzymes and metabolic issues in Diabetes type 2 (DMT2), which is a worldwide disease, Chronic metabolic disorders cause insulin resistance, hyperglycemia, and complications like diabetic nephropathy. Arginase converts arginine to ornithine and urea. Increased arginase activity in DMT2 and diabetes nephropathy (DN)which has been linked to kidney damage, and arginase inhibitors can increase NO which is essential to vascular function. However, the molecular mechanisms of arginased is regulationare in DMT2 and DN are still unclear. This study examined the effect of manganese oxide nanoparticles (Mn2O3NPs) on arginase activity inhibition inserum samples from DMT2 and DN patients. We hypothesized that Mn2O3NPs alter cell redox status and signaling pathways, affecting DMT2 and DN arginase activity. We used a colorimetric assay to measure arginase activity in 80 serum samples from DMT2 and DN patients treated with different MnO2 NP concentrations to test our hypothesis. The current study characterized nanoparticles using various techniques such as IR, SEM, AFM, XRD, and EDX, which found it within nanoscale nature. Our findings are that Mn2O3NPs modulate arginase activity specificity in DM2 samples. SuggestionsMn2O3NPs could be used to develop new treatments for these conditions.

Impacts of Biosynthesized Manganese Dioxide Nanoparticles on Antioxidant Capacity, Hematological Parameters, and Antioxidant Protein Docking in Broilers.

Using green tomato extract, a green approach was used to synthesize manganese oxide nanoparticles (MnO2NPs). The synthesis of MnO2NPs was (20.93-36.85 nm) confirmed by energy-dispersive X-ray (EDX), scanning and transmission electron microscopy (SEM and TEM), Fourier transform infrared spectroscopy (FTIR), and UV-visible spectroscopy (UV-vis) analyses. One hundred fifty-day-old Arbor Acres broiler chicks were randomly divided into five groups. The control group received a diet containing 60 mg Mn/kg (100% NRC broiler recommendation). The other four groups received different levels of Mn from both bulk MnO2 and green synthesized MnO2NPs, ranging from 66 to 72 mg/kg (110% and 120% of the standard level). Each group comprised 30 birds, in three replicates of 10 birds each. Generally, the study's results indicate that incorporating MnO2NPs as a feed additive had no negative effects on broiler chick growth, antioxidant status, and overall physiological responses. The addition of MnO2NPs, whether at 66 or 72 mg/kg, led to enhanced superoxide dismutase (SOD) activity in both serum and liver tissues of the broiler chicks. Notably, the 72 mg MnO2NPs group displayed significantly higher SOD activity compared to the other groups. The study was further justified through docking. High throughput targeted docking was performed for proteins GHS, GST, and SOD with MnO2. SOD showed an effective binding affinity of -2.3 kcal/mol. This research sheds light on the potential of MnO2NPs as a safe and effective feed additive for broiler chicks. Further studies are required to explore the underlying mechanisms and long-term effects of incorporating MnO2NPs into broiler feed, to optimize broiler production and promote its welfare.

Manganese and copper-coated nickel oxide nanoparticles synthesized from Carica papaya leaf extract induce antimicrobial activity and breast cancer cell death by triggering mitochondrial caspases and p53

Abstract In the present work, manganese–copper co-infused nickel oxide nanoparticles (MnCu co-doped NiO NPs) were formulated via a green process using Carica papaya extract. The MnCu co-doped NiO NPs were characterized by X-ray diffraction (XRD), UV–Vis, Fourier transform infrared, field emission scanning electron microscope, energy dispersive X-ray analysis, and photoluminescence (PL) spectrum. The XRD pattern demonstrated that synthesized MnCu co-doped NiO NPs exhibit cubic structure. On the PL spectrum, various surface defects were identified. MnCu co-doped NiO NPs exhibited ferromagnetic properties at 37°C. The antimicrobial activity of green synthesis MnCu co-doped NiO NPs against human pathogens (Escherichia coli, Streptococcus pneumoniae, Bacillus megaterium, Bacillus subtilis, Shigella dysenteriae, Pseudomonas aeruginosa) and Candida albicans as fungal strains were demonstrated. The MnCu co-doped NiO NPs treatment considerably reduced MDA-MB-231 cell viability while not disturbing HBL-100 cell viability. Different fluorescent staining analyses revealed that MnCu co-doped NiO NPs induced nuclear and mitochondrial damage to improve free radical production, altering mitochondrial membrane protein potential, which led to apoptotic cell death in MDA-MB-231 cells. The MnCu co-doped NiO NP treatment enhanced pro-apoptotic protein expression and inhibited the cell cycle at the S phase in MDA-MB-231 cells. This makes it easy, cheap, and environmentally friendly to make MnCu co-doped NiO NPs using C. papaya extract, which has excellent antimicrobial properties.

Synthesis, Characterization, and Toxicity Assessment of Zinc Oxide-Doped Manganese Oxide Nanoparticles in a Macrophage Model.

The doping of engineered nanomaterials (ENMs) is a key tool for manipulating the properties of ENMs (e.g., electromagnetic, optical, etc.) for different therapeutic applications. However, adverse health outcomes and the cellular biointeraction of doped ENMs, compared to undoped counterparts, are not fully understood. Previously, we have shown that doping manganese oxide nanoparticles with ZnO (ZnO-MnO2 NPs) improved their catalytic properties. In this study, we assessed the toxicity of ZnO-MnO2 NPs in Raw 264.7 cells. NPs were prepared via an eco-friendly, co-precipitation method and characterized by several techniques, including transmission and scanning electron microscopy, X-ray diffraction, and Fourier transform infrared. The physicochemical properties of ZnO-MnO2 NPs, including size, morphology, and crystalline structure, were almost identical to MnO2 NPs. However, ZnO-MnO2 NPs showed slightly larger particle aggregates and negative charge in cell culture media. Exposure to ZnO-MnO2 NPs resulted in lower toxicity based on the cell viability and functional assay (phagocytosis) data. Exposure to both NPs resulted in the activation of the cell inflammatory response and the generation of reactive oxygen species (ROS). Despite this, exposure to ZnO-MnO2 NPs was associated with a lower toxicity profile, and it resulted in a higher ROS burst and the activation of the cell antioxidant system, hence indicating that MnO2 NP-induced toxicity is potentially mediated via other ROS-independent pathways. Furthermore, the cellular internalization of ZnO-MnO2 NPs was lower compared to MnO2 NPs, and this could explain the lower extent of toxicity of ZnO-MnO2 NPs and suggests Zn-driven ROS generation. Together, the findings of this report suggest that ZnO (1%) doping impacts cellular biointeraction and the consequent toxicological outcomes of MnO2 NPs in Raw 264.7 cells.

Characterization and Cellular Toxicity Studies of Commercial Manganese Oxide Nanoparticles.

Manganese oxide nanoparticles (MnOx NPs) are finding applications in several environmentally important areas such as farming and energy storage. MnOx NPs span a range of metal oxidation states that open up a wide range of applications in catalysis as well. As a result, it is important to understand how such materials can impact human health through incidental exposure. In this study, we examined a range of commercially available Mn2O3 NPs and compared our characterization data to those supplied by manufacturers. Discrepancies were noted and then measured values were used to assess the biological impact of these materials on three mammalian cell lines-A549, HepG2 and J774A.1 cells. Cell toxicity assays showed that all Mn2O3 particles exhibited cytotoxic effects that may be correlated, at least in part, to the production of reactive oxygen species. All eight nanoforms also activated caspase 3 but not caspase 1, although the magnitude of these changes varied greatly between materials.

Use of manganese oxide nanoparticle (MnO2 NPs) and Pseudomonas putida for the management of wilt disease complex of carrot

Wilt disease complex of carrot is caused by Ralstonia solancearum and Meloidogyne incognita and is responsible for considerable yield loss. Manganese oxide nanoparticle (MnO2 NPs) and Pseudomonas putida were used alone and in combination for the management of wilt disease complex. In vitro, MnO2 NPs 0.10 g.L-l caused 49.36% reduction in hatching and 14.23% mortality of second stage juveniles (J2) of M. incognita while paper disc dipped in MnO2 NPs suspension caused 0.51 mm inhibition zone around R. solanacearum in nutrient agar medium. Inoculation of P. putida to plants with pathogens caused a similar increase in plant growth, chlorophyll and carotenoid contents as caused by foliar spray with 0.10 g.L−1 MnO2 NPs. Use of P. putida with NPs foliar spray to plants with pathogens caused a greater increase in plant growth, chlorophyll and carotenoid contents than with P. putida or NPs foliar spray. Inoculation of M. incognita/R. solanacearum/M. incognita plus R. solanacearum/P. putida/MnO2 NPs and MnO2 NPs plus P. putida caused increase in proline contents. Root colonization by P. putida was reduced in plants with test pathogens. Foliar application of MnO2 NPs and P. putida reduce wilt disease indices. Galling and populations of M. incognita was also reduced in plants co-inoculated with R. solanacearum. The greatest reduction in nematode populations and galling was observed in plants with NPs spray together with P. putida. Principal component analysis demonstrated a clear influence of NPS and P. putida and their combination on various studied parameters in diseased plants.

Antimicrobial activities of copper and manganese oxide nanoparticles against pathogens of tomato plants

Antimicrobial activities of copper and manganese oxide nanoparticles against pathogens of tomato plants