MnO2 NPs Research Articles

An Integrated Therapeutic Nanoparticles and Quorum Quenching‐Based Microneedle Patch for Bacterial‐Infected Wound Healing

AbstractSkin injuries leading to drug‐resistant bacterial infections remain a significant challenge, posing a threat to human health. There is an urgent necessity to develop wound dressings for the treatment of such injuries. The proceeding study presents the design of a multifunctional microneedle (MNs) patch containing quorum‐quenching enzyme and manganese dioxide (MnO2) nanoparticles for treating Pseudomonas aeruginosa‐infected wounds. In co‐culture experiments with P. aeruginosa, the quorum‐quenching enzyme significantly reduced the production of virulence factors and inhibited biofilm formation. MnO2 NPs exhibited excellent scavenging ability against a wide range of free radicals when assayed in in vitro antioxidant assays. Subsequently, soluble hyaluronic acid is chosen as the substrate in order to prepare the MNs patches loaded with quorum quenching enzyme and MnO2 NPs for wound healing assessment in a P. aeruginosa‐infected mouse wound model. Evaluation of wound size and closure rate demonstrated that the patch significantly accelerated wound healing, resulting in shorter healing durations and improved wound closure. Additionally, inflammation‐related cytokine levels are reduced, indicating a lower level of inflammation. Tissue section staining shows that treatment with MNs promoted wound epithelialization, collagen deposition, and angiogenesis. The multifunctional MNs patch represents a promising treatment option for drug‐resistant bacterial infections in wound management.

NK cell membrane/MnO2 hybrid nanoparticle-adjuvanted intranasal vaccines synergistically boost protective immunity against H1N1 influenza infection

Intranasal vaccines hold a huge promise for preventing influenza infection, however, their development is compromised due to mucosal barriers and limited systemic and mucosal immunity. Herein, a novel biomimetic nano-adjuvant based on NK cell membrane (MNK)/MnO2 hybrid nanoparticles (NLipoMn) was developed for intranasal administration of H1N1 inactivated influenza vaccine (IIV). NK cell membrane, served as TLR4 agonist was fused with cationic liposomes encapsulating STING agonist MnO2 NPs (LipoMn) to yield NLipoMn, which inherited versatile characteristics to prolong the nasal retention of IIV. Encouragingly, CCL20 secretion was enhanced by NLipoMn-activated the TLR4/NF-κB pathway in mucosal endothelial cells, thereby promoting submucosal dendritic cells (DCs) recruitment for IIV uptake. Moreover, NLipoMn-IIV synergistically harnessed TLR4 and STING signaling pathway to augment STING activation though NLipoMn-activated the TLR4/NF-κB pathway, which demonstrated a superiority to elicit strong DCs maturation, CD8+ T cells activation, and high levels of antigen-specific IgG, antigen-specific IgA, cytokines secretion, resulting in a robust systemic and mucosal immune responses. Notably, intranasal immunization with NLipoMn-IIV elicited an effective immune protection against homologous and heterologous H1N1 influenza virus infection. This study provides a promising adjuvant candidate to develop needle-free intranasal vaccines that are active against influenza and other respiratory viral infection.

Natural Synthesis, Characterisation, and Photocatalytic Performance of Nanoparticles made of Manganese Dioxide using Manganese Acetate Tetrahydrate as Precursor

Abstract: This study describes a straightforward, effective, and environmentally benign method for producing manganese dioxide nanoparticles (MnO2 NPs) using Nyctanthes arbor-tristis leaf extract. It was discovered by Fourier-transform infrared spectra that the plant extract contributed to the creation of MnO2 NPs. The band gap of the synthesised MnO2 NPs was identified as the source of the absorption peaks observed in the UV–visible absorption spectra at 412 nm. X-ray diffraction analysis was used to identify the crystal phase of the MnO2 NPs and validate the development of crystalline MnO2 NPs. According to the X-ray diffraction pattern, MnO2 NPs have crystalline nature. Furthermore, the synthesised MnO2 NPs' was revealed by field emission scanning electron microscopy investigation with EDS which gives Information about Compositional elements. MnO2 NPs have the ability to degrade MB dyes in the UV-Visible light spectrum by photocatalysis. Using Methylene Blue as an organic pollutant, the photocatalytic activities for the dye degradation of MnO2 NPs were assessed

Ultrasensitive detection platform for Staphylococcus aureus based on DNAzyme tandem blocking CRISPR/Cas12a system

Detection methods based on CRISPR/Cas12a have been widely developed in the application of pathogenic microorganisms to guarantee food safety and public health. For sensitive detection, the CRISPR-based strategies are often in tandem with amplification methods. However, that may increase the detection time and the process may introduce nucleic acid contamination resulting in non-specific amplification. Herein, we established a sensitive S. aureus detection strategy based on the CRISPR/Cas12a system combined with DNAzyme. The activity of Cas12a is blocked by extending the spacer of crRNA (bcrRNA) and can be reactivated by Mn2+. NH2-modified S. aureus-specific aptamer was loaded on the surface of Fe3O4 MNPs (apt-Fe3O4 MNPs) and MnO2 NPs (apt-MnO2 NPs) by EDC/NHS chemistry. The S. aureus was captured to form apt-Fe3O4 MNPs/S. aureus/apt-MnO2 NPs complex and then MnO2 NPs were etched to release Mn2+ to activate DNAzyme. The active DNAzyme can cleave the hairpin structure in bcrRNA to recover the activity of the CRISPR/Cas system. By initiating the whole detection process by generating Mn2+ through nanoparticle etching, we established a rapid detection assay without nucleic acid extraction and amplification process. The proposed strategy has been applied in the ultrasensitive quantitative detection of S. aureus and has shown good performance with an LOD of 5 CFU/mL in 29 min. Besides, the proposed method can potentially be applied to other targets by simply changing the recognition element and has the prospect of developing a universal detection strategy.

Brain-targeting biomimetic disguised manganese dioxide nanoparticles via hybridization of tumor cell membrane and bacteria vesicles for synergistic chemotherapy/chemodynamic therapy of glioma

Glioma is a prevalent brain malignancy associated with poor prognosis. Although chemotherapy serves as the primary treatment for brain tumors, its effectiveness is hindered by the limited ability of drugs to traverse the blood–brain barrier (BBB) and the development of drug resistance linked to tumor hypoxia. Herein, we report the creation of hybrid camouflaged multifunctional nanovesicles comprising membranes of tumor C6 cells (mT) and bacterial outer membrane vesicles (OMVs) and co-loaded with manganese dioxide nanoparticles (MnO2 NPs) and doxorubicin (DOX) to synergistically enhance the chemotherapy/chemodynamic therapy (CDT) of glioma. Owing to OMV-mediated BBB penetration and mT-inherited tumor-homing properties, MnO2-DOX@mT/OMVs can penetrate the BBB and enhance the tumor cell-specific uptake of DOX via “proton sponge effect”-mediated lysosomal escape. This enhances the apoptotic effect induced by DOX and minimizing DOX-associated cardiotoxicity by facilitating the accumulation of DOX at the tumor site. Furthermore, the MnO2 NPs in MnO2-DOX@mT/OMVs can generate potent CDT by accelerating the Fenton-like reaction with DOX-generated H2O2 and achieving glutathione (GSH)-depletion-induced glutathione peroxidase 4 (GPX4) inactivation. These results showed that MnO2-DOX@mT/OMVs, designed for brain tumor targeting, significantly inhibited tumor growth and exhibited favorable biological safety. This innovative approach offers the augmentation of anticancer treatment efficacy via a potential combination of chemotherapy and CDT.

Antibacterial Activity of Piper betle Leaf Extract Mediated MnO2 Nanoparticles

The biogenesis of manganese dioxide nanoparticles using Piper betle leaf extract is explained in this work as a simple, environment friendly and effective process. Using Piper betle leaf extract as a reducing agent, potassium permanganate was reduced to synthesize the MnO2 NPs. The contribution of the biomolecules in the Piper betle leaf extract to the production of MnO2 NPs was revealed by Fourier-transform infrared spectra. The biosynthesized MnO2 NPs' UV–visible spectra showed absorption peaks around 271 nm, which is the MnO2 NPs' absorption maxima. According to the scanning electron microscopy study, the 70–80 nm-sized biosynthesized MnO2 NPs exhibit an irregular form. The presence of Mn and O in the MnO2 NPs was verified by EDAX. MnO2 NPs were tested for their antibacterial properties against Bacillus subtilis, Bacillus cereus, and Bacillus amyloliquefaciens. The antibacterial activity of the biosynthesized MnO2 NPs is mild.

A facile green synthesis of manganese oxide nanoparticles using gum karaya polymer as a bioreductant for efficient photocatalytic degradation of organic dyes and antibacterial activity

The release of organic dyes into water systems, mainly textile industries, poses a significant threat to human and animal health. This approach shows great potential for effectively removing harmful dyes and microorganisms from wastewater treatment for environmental remediation. This study utilized gum karaya polymer bio-reductant to synthesize manganese oxide (MnO2) nanoparticles through a green approach. The synthesized MnO2 nanoparticles were characterized and confirmed by various analytical techniques. These results revealed their nanoscale dimensions, morphology, chemical purity, crystal nature, decolorized intermediate, and band gap. The photocatalytic degradation of hazardous Congo red and methyl orange dyes using KRG-MnO2 nanoparticles under visible light irradiation. Furthermore, the results demonstrated that Congo red dye degradation efficiency of 93.34 % was achieved. The dye concentration (8 to 16 mg/L), pH concentration, and radical trapping were studied. This suggests that holes and hydroxyl radicals play a crucial role in degrading the Congo red dye and demonstrate superior recyclability after three successive cycles and good stability. The possible intermediates from the Congo red dye degradation were identified through LC-MS analysis. The polymer composite MnO2 NPs have displayed notable antibacterial activity against pathogenic bacteria such as Staphylococcus aureus and Escherichia coli. The research indicates that MnO2 nanoparticles functionalized with polymers can efficiently remove pathogens and organic dyes from diverse industrial water treatment processes.

Glycogen-assisted biosynthesis of MnO2 for adsorptive elimination of methylene blue from water

A novel biosynthesis of manganese dioxide (MnO2) NPs was achieved by oxidizing glycogen with KMnO4 in an alkaline medium. X-ray powder diffraction, Fourier-transform infrared spectroscopy, N2 sorption, and transmission electron microscope (TEM) techniques were utilized to assess the physicochemical characteristics of the prepared MnO2. The impacts of different adsorption parameters, including contact time, pH, concentration, temperature, and adsorbent dose, on methylene blue (MB) elimination utilizing the prepared MnO2 NPs, were investigated. It was found that the Langmuir model well describes how the dye molecules arrange themselves on the MnO2 surface compared to other models. This proposes a single layer of dye forms, with each molecule attaching to a specific site on the MnO2. Additionally, the results were well-matched with a pseudo-2nd-order model, demonstrating that chemical reactions had a significant role in the adsorption experiment. Under specific conditions (RT, natural pH of the dye solution, and 30-minute contact time), the MnO2 could hold up to 40.85 mg of dye per gram of MnO2 (mg/g). Further analysis reflected that the adsorption procedure was spontaneous, which means it happened favorably without needing extra energy input. This suggests that biosynthesized MnO2 has great potential as an eco-friendly material for cleaning up MB dye contamination in water.

Potential in-vitro antioxidant and anti-inflammatory activity of Martynia annua extract mediated Phytosynthesis of MnO2 nanoparticles

The present research work describes the phyto-synthesis of Manganese dioxide nanoparticles (MnO2NPs) from the reduction of potassium permanganate using Martynia annua (M.annua) plant extract. From the literature review, we clearly understood the M.annua plant has anti-inflammatory activity. Manganese dioxides are important materials due to their wide range of applications. Their increased surface area gives them distinct capabilities, as it increases their mechanical, magnetic, optical, and catalytic qualities, allowing them to be used in more pharmaceutical applications. A detailed review of literature highlighting the issues related to this present work and its knowledge gap that none of the inflammatory activities had been done by MnO2 NPs synthesized from M.annua plant extract. So we selected this study. The product MnO2 NPs showed the wavelength centre at 370 nm and was monitored by UV–Vis spectra. The wave number around 600 cm−1 has to the occurrence of O–Mn–O bonds of pure MnO2 confirmed by FTIR spectroscopy. Transmission electron microscopy images showed the morphology of MnO2 NPs as spherical-shaped particles with average sizes at 7.5 nm. The selected area electron diffraction analysis exhibits the crystalline nature of MnO2 NPs. The obtained MnO2 NPs showed potential antioxidant and anti-inflammatory activity was compared to the plant extract. The synthesized MnO2 NPs have a large number of potential applications in the field of pharmaceutical industries. In the future, we isolate the phytocompounds present in the M.annua plant extract and conduct a study against corona virus. MnO2 produces manganese (III) oxide and oxygen, which increases fire hazard. But further research is required to understand their environmental behaviour and safety.

Reactive Oxygen Species Scavenging Injectable Hydrogel Potentiates the Therapeutic Potential of Mesenchymal Stem Cells in Skin Flap Regeneration.

Cell-based therapies offer tremendous potential for skin flap regeneration. However, the hostile microenvironment of the injured tissue adversely affects the longevity and paracrine effects of the implanted cells, severely reducing their therapeutic effectiveness. Here, an injectable hydrogel (nGk) with reactive oxygen species (ROS) scavenging capability, which can amplify the cell viability and functions of encapsulated mesenchymal stem cells (MSCs), is employed to promote skin flap repair. nGk is formulated by dispersing manganese dioxide nanoparticles (MnO2 NPs) in a gelatin/κ-carrageenan hydrogel, which exhibits satisfactory injectable properties and undergoes a sol-gel phase transition at around 40 °C, leading to the formation of a solid gel at physiological temperature. MnO2 NPs enhance the mechanical properties of the hydrogel and give it the ability to scavenge ROS, thus providing a cell-protective system for MSCs. Cell culture studies show that nGk can mitigate the oxidative stress, improve cell viability, and boost stem cell paracrine function to promote angiogenesis. Furthermore, MSC-loaded nGk (nGk@MSCs) can improve the survival of skin flaps by promoting angiogenesis, reducing inflammatory reactions, and attenuating necrosis, providing an effective approach for tissue regeneration. Collectively, injectable nGk has substantial potential to enhance the therapeutic benefits of MSCs, making it a valuable delivery system for cell-based therapies.

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.

Green synthesis of MnO2 NPs using Arabic gum: assessing its potential antiviral activity against influenza A/H1N1

BackgroundThe antiviral properties of metal nanoparticles against various viruses, including those resistant to drugs, are currently a subject of intensive research. Recently, the green synthesis of nanoparticles and their anti-viral function have attracted a lot of attention. Previous studies have shown promising results in the use of Arabic gum for the green synthesis of nanoparticles with strong antiviral properties. In this study we aimed to investigate the antiviral effects of MnO2 nanoparticles (MnO2-NPs) synthesized using Arabic gum, particularly against the influenza virus.MethodsArabic gum was used as a natural polymer to extract and synthesize MnO2-NPs using a green chemistry approach. The synthesized MnO2-NPs were characterized using SEM and TEM. To evaluate virus titration, cytotoxicity, and antiviral activity, TCID50, MTT, and Hemagglutination assay (HA) were performed, respectively. Molecular docking studies were also performed to investigate the potential antiviral activity of the synthesized MnO2-NPs against the influenza virus. The molecular docking was carried out using AutoDock Vina software followed by an analysis with VMD software to investigate the interaction between Arabic gum and the hemagglutinin protein.ResultsSimultaneous combination treatment with the green-synthesized MnO2-NPs resulted in a 3.5 log HA decrement and 69.7% cellular protection, which demonstrated the most significant difference in cellular protection compared to the virus control group (p-value < 0.01). The docking results showed that binding affinities were between − 3.3 and − 5.8 kcal/mole relating with the interaction between target with MnO2 and beta-D-galactopyranuronic acid, respectively.ConclusionThe results of the study indicated that the MnO2-NPs synthesized with Arabic gum had significant antiviral effects against the influenza virus, highlighting their potential as a natural and effective treatment for inhibition of respiratory infections.

Tailored spherical-sea urchin-like MnO2-AC/PTA nanocomposites for superior photocatalytic degradation of BPA and Orange II dye, along with bacteria Inactivation: Mechanistic insights

In this study, we present a pioneering approach introducing a novel spherical-sea urchin-like MnO2-KAFC/PTA (Manganese dioxide/KOH activated foam derived carbon/Phosphotugstic acid) nanocomposite photocatalyst for photocatalytic degradation of organic pollutants and bacteria inactivation. It is well-established that the reactivity in photocatalytic applications heavily relies on the shape and crystallographic orientation of the photocatalysts. Thus, we synthesized controllable MnO2-KAFC/PTA NCs with spherical-sea urchin-like morphologies using the in-situ precipitation method. Subsequently, the synthesized KAFC, MnO2 NPs, and spherical-sea urchin-like MnO2-KAFC/PTA NCs were systematically characterized in detail. Following characterization, they were employed as photocatalysts for photocatalytic degradation of Bisphenol A (BPA) and Orange II dye pollutants, as well as for the inactivation of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The spherical-sea urchin-like MnO2-KAFC/PTA NCs photocatalyst demonstrated outstanding photocatalytic degradation efficiency, achieving rates of 99.8% and 99.9% for BPA and Orange II dye, respectively, under sunlight irradiation. Notable, the spherical-sea urchin-like MnO2-KAFC/PTA NCs exhibited excellent degradation efficiency (99.8 and 99.9%) compared to MnO2 NPs (40 and 51%), and KAFC (26 and 21%), respectively. Furthermore, the optimized spherical-sea urchin-like MnO2-KAFC/PTA NCs photocatalysts were subjected to bactericidal testing against E.coli and S. aureus pathogens. The results revealed that the optimal antibacterial efficacy against E.coli and S. aureus microbes was zone inhibition up to 18 mm and 20 mm, respectively. Overall, the present study underscores the efficacy of spherical-sea urchin-like MnO2-KAFC/PTA NCs as potent antibacterial and degrading agents.

Optimizing Oxygen-Production Kinetics of Manganese Dioxide Nanoparticles Improves Hypoxia Reversal and Survival in Mice with Bone Metastases.

Persistent hypoxia in bone metastases induces an immunosuppressive environment, limiting the effectiveness of immunotherapies. To address chronic hypoxia, we have developed manganese dioxide (MnO2) nanoparticles with tunable oxygen production kinetics for sustained oxygenation in bone metastases lesions. Using polyethylene glycol (PEG)-stabilized MnO2 or poly(lactic[50]-co-glycolic[50] acid) (50:50 PLGA), poly(lactic[75]-co-glycolic[25] acid) (75:25 PLGA), and polylactic acid (PLA)-encapsulated MnO2 NPs, we demonstrate that polymer hydrophobicity attenuates burst oxygen production and enables tunable oxygen production kinetics. The PEG-MnO2 NPs resulted in rapid hypoxia reduction in spheroids, which was rapidly attenuated, while the PLA-MnO2 NPs exhibited delayed hypoxia control in cancer spheroids. The 50:50 PLGA-MnO2 NPs exhibited the best short- and long-term control of hypoxia in cancer spheroids, resulting in sustained regulation of the expression of HIF-1α and immunosuppressive genes. The sustained control of hypoxia by the 50:50 PLGA-MnO2 NPs enhanced the cytotoxicity of natural killer cells against cancer spheroids. In vivo, 50:50 PLGA-MnO2 showed greater accumulation in the long bones and pelvis, common sites for bone metastases. The NPs decreased hypoxia in bone metastases and decreased regulatory T cell levels, resulting in enhanced survival of mice with established bone metastases.

Facile synthesis of MnO2 nanoparticles for the removal of cationic dye

Abstract MnO2 NPs were synthesized from Delonix elata leaves extract act as a capping and reducing agent by green synthesis process. The synthesized MnO2 NPs were characterized by different spectroscopic techniques such as IR, UV-Vis, SEM and XRD analyses. The UV spectrum of synthesized MnO2 NPs revealed optical properties at 340 nm. The XRD pattern of MnO2 NPs exhibited the crystallite size to be in the range of 20 nm and shows the amorphous structure. The morphological geographies of MnO2 NPs are spherical and faintly agglomerated. The FT-IR spectrum of MnO2 NPs spectacles stretching vibration of Mn–O at 510 cm−1 confirmed the formation of MnO2 NPs. MnO2 is superior photo degradation for methylene blue which is extant in the textile industries and it has an unlimited potential application in wastewater treatment.

Synergistic chemoradiotherapy of cervical cancer cells using a pH- and radiation-sensitive doxorubicin-loaded β-cyclodextrin-based nanocomposite hydrogel containing MnO2 nanoparticles

It is an undoubted fact that remarkable clinical outcomes have demonstrated by synergistic chemoradiotherapy (CRT) approach, in comparison to solitary radiation therapy (RT) or chemotherapy (CT). Therefore, a novel pH- and radiation-sensitive nanocomposite hydrogel, β-cyclodextrin-graft-poly(succinic ethyl methacrylate)/MnO2 nanoparticles (β-CD-g-PSEMA/MnO2 NPs), was designed and developed through grafting 2-hydroxyethyl methacrylate (HEMA) onto functionalized β-CD through atom transfer radical polymerization (ATRP) followed by crosslinking β-CD-g-PHEMA-Br and bromine end-capped MnO2 NPs with Na2Se moiety to incorporate radiation-sensitive bonds into the hydrogel. The hydroxyl groups of PHEMA segments were converted to monomethyl succinate groups to induce pH sensitivity. Subsequently, the system was physically loaded with doxorubicin (Dox). In vitro drug release study revealed pH-dependent drug release behavior and the highest drug release value was obtained as 64.7% at pH 5. Oxygen generation from the developed drug delivery system (DDS) was confirmed, which the DDS could improve the efficiency of radiation therapy by oxygen generating in the cancer hypoxia environment. Intracellular uptake of the DDS was confirmed via FITC dye conjugation strategy. In contrast to free Dox, the developed DDS exhibited higher anticancer activity after 48 hours as validated by MTT and DAPI staining methods by synergistic CRT approach in moderate radiation dose.

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.

Three-dimensional Au-MnO2 nanostructure as an agent of synergistic cancer therapy: chemo-/photodynamic and photothermal approaches.

The design of multimodal cancer therapy was focused on reaching an efficient process and minimizing harmful effects on patients. In the present study, the Au-MnO2 nanostructures have been successfully constructed and produced as novel multipurpose photosensitive agents simultaneously for photodynamic therapy (PDT), photothermal therapy (PTT), and chemodynamic therapy (CDT). The prepared AuNPs were conjugated with MnO2 NPs by its participation in the thermal decomposition process of KMnO4 confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy (FT-IR). The 16.5 nm Au-MnO2 nanostructure exhibited an absorbance at 438 nm, which is beneficial for application in light induction therapy due to the NIR band, as well as its properties of generating reactive oxygen species (ROS) associated with the 808 nm laser light for PDT. The photothermal transduction efficiency was calculated and compared with that of the non-irradiated nanostructure, in which it was found that the 808 nm laser induced a high efficiency of 83%, 41.5%, and 37.5% for PDT, PTT, and CDT, respectively. The results of DPBF and TMB assays showed that the efficiency of PDT and PTT was higher than that of CDT. The nanostructure also confirmed the time-dependent peroxidase properties at different H2O2, TMB, and H2TMB concentrations, promising good potency in applying nanomedicine in clinical cancer therapy.

Green Synthesis of MnO2 Nanoparticles with Aqueous Extract of Star Apple Leaves (Chrysophyllum cainito L.)

Nanomaterials are materials with a size of ≤100 nm and are important for technology in today’s digital era. MnO2 is one of the most studied metal oxides nowadays because of its abundance, low toxicity, and environmentally friendly. This material can be synthesized via redox reactions. The reagents commonly used in this reaction are typically toxic and environmentally unfriendly, such as H2SO4, HCl and HNO3. Therefore, through this research, the synthesis of MnO2 was carried out using an aqueous extract of star apple leaves. Because the aqueous extract of star apple leaves is known to contain secondary metabolites which have -OH, -C=O, and -C-N groups. These groups act as reducing and capping agents for the synthesis of MnO2 NPs. In addition, this study investigated the effect of the various synthesis methods on the formation of MnO2 NPs. Based on the results of LC-MS characterization, the aqueous extract of star apple leaves contains myricetin. Myricetin has -C=O and -OH groups which are reactive to MnO4- ions in aqueous solution, so that MnO4- is reduced to MnO4. This fact is supported by the results of the P-XRD characterization, which proves the presence of R-MnO2 and γ- MnO2 were obtained.

Eco-friendly synthesized manganese dioxide nanoparticles using Tridax procumbens as potent antimicrobial and dye degrading agent

Manganese dioxide nanoparticles (MnO2 NPs) were synthesized via a typical green synthesis method involving Tridax procumbens (TP) leaf extract extraction and utilization. The as-prepared material was further characterized using various physio-chemical methods to comprehend its structural, morphological, and optical properties. Powder X-ray diffraction (PXRD) reveals a tetragonal system with a space group of I 41/a m d, clearly indicating the presence of phytochemicals (impurity peaks at 25.46° and 54.92° diffraction angles). The calculated crystalline size of the sample was found to be 43 nm. Field Emission Scanning Electron Microscope (FESEM) results confirm the precursors of the as-prepared sample, also revealing the agglomerated structure. Furthermore, deeper morphology and crystallinity of the as-prepared MnO2 NPs have been studied through High-Resolution Transmission Electron Microscope (HR-TEM) images, which affirms the information about calculated d-spacing value (0.328 nm) and confirming crystallinity through Selected Area Electron Diffraction (SAED) image. Absorption studies were conducted on as-prepared samples, which show a characteristic band at 257 nm, affirming the formation of MnO2 NPs. The same was utilized to evaluate the band gap energy (4.46 eV) through the Kubelka-Munk function. To further confirm the calculated particle size and stability of the as-prepared MnO2 NPs, Dynamic Light Scattering (DLS) analysis was conducted, and the results revealed that the particles’ size was 58.72 nm. The prepared samples were subjected to study antimicrobial studies against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacterial species. The inhibition zone of the antibacterial disc soaked with as-prepared MnO2 NPs showed a significant increase compared to the TP leaf extract and commercially available MnO2 NPs. Also, the degradation of the Titan Yellow dye solution was conducted employing UV irradiation, and it was found that the maximum degradation percentage was attained after 120 min of irradiation. Furthermore, the pH effect on %degradation and reusability test were also conducted. The obtained results showed a pinnacle pH point of 4 where the degradation was maximum and found a decent decrement in %degradation after 4th usage. All the acquired results were utilized to study the degradation reaction kinetics, which was found that the present degradation holds good for both 0th and 1st order kinetic equations. Henceforth, the acquired results suggest that the green synthesized MnO2 NPs are potent candidates for antimicrobial and degrading activities.