MnO2 Nanoparticles Research Articles

G–C3N4–assisted synthesis of ultrafine Mn2O3 nanoparticles embedded into N–doped carbon for advanced lithium–ion battery anode

The construction of advanced transition metal oxide (TMO)/carbon anodes to substitute graphite is always being an enormous challenge for the evolution of lithium–ion batteries (LIBs). Herein, a g–C3N4–assisted pyrolysis strategy is exploited to produce Mn2O3 nanoparticles embedded into N–doped carbon (Mn2O3@NC) hybrids. The results confirm that g–C3N4 plays three critical roles (dispersing agent, pore–forming agent and doping agent) in producing Mn2O3@NC hybrids. In the meantime, it is verified that the feed of Mn source greatly affects the synthesis of Mn2O3@NC hybrids. As a consequence, the resultant Mn2O3@NC–M (M means medium loading of Mn source) reaches a balanced proportion of Mn2O3 and NC, and contemporaneously displays a series of intriguing features, including ultrafine Mn2O3 nanoparticles, large specific surface area, rich mesopores and much high N doping amount. Benefitting from these advantages, the obtained Mn2O3@NC–M shows much enhanced cycling stability and rate performance when engaged as an battery anode.

Controllable synthesis of MnO nanoparticles supported on porous carbon as a highly active oxidase mimic for dopamine detection

Mn(II) ion has emerged as a cofactor in heme-copper oxidase to confer O2 reduction to H2O, which shares the similar mechanism with oxidase mimicking reaction, so it is fascinating and interesting to explore the oxidase mimetic activity of Mn(II) compound. Here, MnO nanoparticles supported on porous carbon (MnO NPs/PC) was controllably prepared via in-situ conversion of MnO2 nanobelts supported on porous carbon (MnO2 NBs/PC). The oxidase mimetic activity of MnO NPs/PC was investigated using 3,3′,5,5′-tetramethyl-benzidine (TMB) as chromogenic substrate. MnO NPs/PC shows excellent oxidase mimetic activity with a low kinetic parameter Km of 0.0214 mM and a high Vmax of 7.21 × 10−7 M/s. Due to the inhibition effect on TMB color reaction, dopamine (DA) can be detected using MnO NPs/PC-TMB chromogenic system, even in human serum samples. This work not only provides a controllable synthetic method for small-sized MnO NPs, but also throws the light on MnO oxidase mimetic activity for the first time.

Investigation of the Defect and Intensity-Dependent Optical Limiting Performance of MnO2 Nanoparticle-Filled Polyvinylpyrrolidone Composite Nanofibers.

To enhance the optical limiting behavior triggered by nonlinear absorption (NA), wide-band gap MnO2 nanoparticles were incorporated into polyvinylpyrrolidone (PVP) polymer nanofibers at various concentrations. SEM images of the composite nanofibers showed that MnO2 nanoparticles are well entrapped in the nanofibers. With an increase in MnO2 nanofiller concentration, a widened optical band gap energy and an increased Urbach energy were observed. As the concentration of MnO2 nanofiller in PVP increased, the NA behavior became more pronounced but weakened with higher input intensity. This behavior was attributed to the filling of the localized defect states by one photon absorption (OPA). The NA mechanisms of the composite nanofibers were examined, considering their band gap energies and localized defect states. Although all of the composite nanofibers had OPA, sequential/simultaneous two photon absorption (TPA), and excited state absorption mechanisms, the higher concentration of the MnO2 nanofiller led to stronger NA behavior due to its more defective structure. The highest optical limiting behavior was observed for composite nanofibers with the highest concentration of MnO2 nanofiller. The results obtained show that these composite nanofibers with a high linear transmittance and an extended band gap energy can be used in optoelectronic applications that can operate in a wide spectral range. Furthermore, their robust NA behavior, coupled with their promising optical limiting characteristics, positions them as strong contenders for effective optical limiting applications.

A high performance selectively grown nano-octahedral Mn3O4 on lignin derived laser scribed graphene for microsupercapacitor applications

Porous graphene infused with mixed valency metal oxide as a supercapacitor material has received much attention. However, the existing approach to directly infusing mixed valency metal oxide such as Mn3O4 on graphene electrodes results in poor electrochemical performance. We report the facile fabrication of oil palm lignin derived laser scribed graphene with sol-gel hydrothermal grown nano-octahedral shaped Mn3O4 nanoparticles to boost the electrochemical performance of the flexible hybrid microsupercapacitor. The newly formed Mn3O4 nanoparticles (Mn3O4 NPs) were octahedral shaped and 15 to 30 nm in size, without any agglomeration and detrimental effect on the porosity of the laser scribed lignin-graphene. Further, the addition of Mn3O4 NPs grown for 3 h increased the specific surface area of the lignin-graphene by 66 %, which improved the microsupercapacitor's areal capacitance by five times to 136.19 mFcm−2 at 0.08 mAcm−2 measured in PAAS/K2SO4 gel electrolyte. The resulting highly stable and pliable microsupercapacitor retained 93.4 of its initial capacitances over 5000 charge-discharge cycles at 0.5 mAcm−2 and 97 % over 400 bending cycles at 50 mVs−1, respectively. The direct synthesis of Mn3O4 on IDE-patterned lignin-derived LSG electrodes presents new possibilities in energy storage applications.

Sensitive and Selective Dual-Mode Responses to Reactive Oxygen Species by Chiral Manganese Dioxide Nanoparticles for Antiaging Skin.

Excessive accumulation of reactive oxygen species (ROS) can lead to oxidative stress and oxidative damage, which is one of the important factors for aging and age-related diseases. Therefore, real-time monitoring and the moderate elimination of ROS is extremely important. In this study, a ROS-responsive circular dichroic (CD) at 553nm and magnetic resonance imaging (MRI) dual-signals chiral manganese oxide (MnO2 ) nanoparticles (NPs) are designed and synthesized. Both the CD and MRI signals show excellent linear ranges for intracellular hydrogen peroxide (H2 O2 ) concentrations, with limits of detection (LOD) of 0.0027nmol/106 cells and 0.016nmol/106 cells, respectively. The lower LOD achieved with CD detection may be attributable to its higher anti-interference capability from the intracellular matrix. Importantly, ROS-induced cell aging is intervened by chiral MnO2 NPs via redox reactions with excessive intracellular ROS. In vivo experiments confirm that chiral MnO2 NPs effectively eliminate ROS in skin tissue, reduce oxidative stress levels, and alleviate skin aging. This approach provides a new strategy for the diagnosis and treatment of age-related diseases.

Experimental evaluation of kinetics and biochemical characteristics of MnO2 nanoparticles as high throughput peroxidase-mimetic nanomaterials

Despite the well-known concepts on the intrinsic peroxidase-like activity of MnO2 nanoparticles, up to date, their biochemical and kinetics characteristics were not investigated, especially, the current information about their performances toward n-electron oxidation of 3, 3′-diaminobezedine for producing indamine polymers is on limitation. Therefore, herein, the MnO2 nanoparticles were synthesized by a simple low-cost co-precipitation method and then characterized by XRD, SEM, and DLS analysis. Besides, their peroxidase-like activity was evaluated upon standard peroxidase enzyme assay, revealing high intrinsic peroxidase-like activity for the as-mentioned MnO2 nanozymes. Considering their high intrinsic peroxidase-like activity, their optimal biochemical characteristics were quantified by probing the progress of -electron irreversible oxidation of 3, 3′-diaminobezedine in the presence of MnO2 nanozymes as peroxidase mimics. The maximal activity of the as-mentioned MnO2 nanoparticles with high intrinsic peroxidase-like activity was observed when the pH and temperature of the reaction media were fixed over 3.0–6.0 and 23℃–25℃, in order, revealing very high pH and thermal stability of the as-prepared nanoparticles. The salt stability of these nanoparticles was also checked using NaCl as model salt, revealing that the nanozymatic activity was stable over a salt concentration as high as 3–7 M. In addition, the affinity constant (Km) and maximum velocity of the nanozyme-catalyzed oxidation of 3, 3′-diaminobezedine were found to be 1.6 mM and 47 nM sec−1, in turn.

Effect of reducing agents on structural, morphological, optical and electrochemical properties of Mn2O3 nanoparticles by co-precipitation method

Abstract In this work, two different reducing agents namely sodium hydroxide and potassium hydroxide (NaOH and KMnO4) were used to synthesis of manganese oxide (Mn2O3) nanoparticles by the co-precipitation method and examined for the electrochemical applications. The as-prepared Mn2O3 nanoparticles using NaOH precursor, dried in a hot oven at 80 °C for 6 h (MN-1) and then annealed for 7 h at 600 °C (MN-2). Similarly, Mn2O3 nanoparticles were prepared using KMnO4 precursor, dried in a hot oven at 80 °C for 6 h (MK-1) and then annealed for 7 h at 450 °C (MK-2), respectively. The influences of reducing agents on structural, morphological and optical properties were investigated. The structural analysis revealed the prepared samples had tetragonal crystal structures with better crystallinity. FT-IR spectral analysis revealed the characteristic bonds of Mn–O–Mn were observed in the region of 486–573 cm−1. The FE-SEM and HR-TEM images showed coral-like and nanorod structures for samples MN-2 and MK-2, with exhibited lattice value of 0.27 nm related to the (222) plane. The presence of the elements manganese (Mn) and oxygen (O) was confirmed by EDAX mapping. The XPS study confirmed that the oxidation state of the prepared samples was +2. The UV-Vis spectra suggested that the adsorption edge was blue-shifted compared to the sample MN-2. Cyclic voltammetry (CV) and galvanostatic charge–discharge experiments demonstrated that charge storage in Mn2O3 exhibited faradic-dominated capacitive behavior. MN-2 nanorod structures were obtained at excellent specific capacitance value of 196 F g−1 compared to MK-2 nanoparticles. Based on this study, Mn2O3 nanoparticles was recommended as exceptional electrode materials for efficient supercapacitor applications due to its superior electrical conductivity, large surface area and redox properties.

Pyridinic and Pyrrolic-N induced carbon nanotubes support bimetallic oxide nanoparticles as high-performance electrocatalysts for oxygen reduction reaction

In-expensive MnO2-based nanostructure has been considered the ideal electrode material for oxygen reduction reaction (ORR) in fuel cell technology. Regardless of their highly active ORR performance, the fuel cross-over capacity and stability of MnO2-based catalysts are still far from satisfying. Herein, we report the highly active SnO2 nanoparticles (NPs) integrated on N-induced carbon nanotube (SnO2@NC) are combined with MnO2 nanoparticles through the electrodeposition to form effective nanostructured in which the MnO2 NPs and SnO2@NC in situ grown on a glassy carbon electrode (MnO2/SnO2@NC) with well-controlled reaction parameters, that exhibits superior ORR activity for the first time. We assessed the marginal role of pyridinic-N and pyrrolic-N in the electrocatalytic ORR activity, synthesis of MnO2/SnO2 bimetallic oxide electrocatalysts, and distribution behavior of NPs. Bimetallic MnO2/SnO2@NC electrode has unique synergistic interactions between MnO2/SnO2 NPs and NC support, which increases electro-active sites, and fast charge transfers towards ORR as compared to other as-prepared electrodes on account of the rational design of the electrode-electrolyte interface plays a significant role in expediting the ORR kinetics. Additionally, the surface nanostructure features, crystalline structure, as well as electronic chemical states of the MnO2/SnO2 NPs embedded in N-induced CNTs, were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Furthermore, bimetallic MnO2/SnO2@NC nanostructure leads an outstanding ORR performance in the 0.1 M KOH electrolyte, delivering a halfwave potential (-0.878 V) and remarkable limiting current density (-4.14 mA cm−2) and much better tolerance to the ethanol cross-over effect with high stability. Thus, the present strategy opens a new path to the design of a pyridinic-N and pyrrolic-N-oriented bimetallic oxide nanostructure as a high-active electrocatalyst for ORR application.

Influence of Mg doping on the structural and optical properties of manganese oxide (Mn2O3) nanoparticles

The work presents here the synthesis of pristine manganese oxide (Mn2O3) nanoparticles and magnesium (Mg) doped Mn2O3nanoparticles with the help of the chemical co-precipitation method. We have investigated the influence of Mg doping (9 wt%, 12 wt%, and 15 wt%) on the optical and structural properties of Mn2O3. The structural properties of undoped and doped Mn2O3 nanoparticles have been studied using X-ray Diffraction Spectroscopy (XRD). The numerous physiochemical bondings present within the prepared nanoparticles have been examined using Fourier Transform Infrared Spectroscopy (FTIR). Both photoluminescence (PL) and UV-Visible (UV-Vis) spectroscopy have been used to investigate the optical characteristics. All the measurements are done at room temperature. All of the samples’ absorption spectra have been investigated within the wavelength range of 200 to 800 nm. The UV-Vis absorption spectrum for pristine Mn2O3 nanoparticles shows a sharp peak at 289 nm. We have further determined the band gap of the prepared samples using Tauc’s equation. The pristine Mn2O3 exhibits a direct bandgap of 4.04eV. At an excitation wavelength of 320 nm, the prepared samples’ emission spectra have also been recorded.

A two-step strategy for the preparation of ultra-small Mn3O4 @C anode for lithium-ion batteries

Nano-engineering and hybrid with carbon are effective methods for improving the electrochemical performance of Mn3O4 anodes. However, there are many difficulties in further reducing the size of Mn3O4. To solve these challenges, a novel hollow microsphere structure constituted of ultra-small Mn3O4 nanoparticles (less than 5 nm) embedded within ultrathin carbon nanosheets is designed as anode materials by a simple two-step heating treatment method. The ultra-small Mn3O4 nanoparticles will accelerate the kinetic reaction process and relieve volume variation. Meanwhile, In-situ fabrication of conductive carbon nanosheets play an important role in the electronic/ion transfer and the structure stability. Due to the synergistic effect of ultra-small Mn3O4 nanoparticles and carbon nanosheets, the material shows a topmost reversible capacity of 804 mAh g−1 at the current density of 1 C and maintains a high specific capacity of 603 mAh g−1 after 700 cycles. The strategy can be extended to prepare of other functional nanoparticles and apply in energy storage and catalysis.

Unveiling the potential of PANI@MnO2@rGO ternary nanocomposite in energy storage and gas sensing

The development of advanced materials for energy storage and gas sensing applications has gained significant attention in recent years. In this study, we synthesized and characterized PANI@MnO2@rGO ternary nanocomposites (NCs) to explore their potential in supercapacitors and gas sensing devices. The ternary NCs were synthesized through a multi-step process involving the hydrothermal synthesis of MnO2 nanoparticles, preparation of PANI@rGO composites and the assembly to the ternary PANI@MnO2@rGO ternary NCs. The structural, morphological, and compositional characteristics of the materials were thoroughly analyzed using techniques such as XRD, FESEM, TEM, FTIR, and Raman spectroscopy. In the realm of gas sensing, the ternary NCs exhibited excellent performance as NH3 gas sensors. The optimized operating temperature of 100 °C yielded a peak response of 15.56 towards 50 ppm NH3. The nanocomposites demonstrated fast response and recovery times of 6 s and 10 s, respectively, and displayed remarkable selectivity for NH3 gas over other tested gases. For supercapacitor applications, the electrochemical performance of the ternary NCs was evaluated using cyclic voltammetry and galvanostatic charge-discharge techniques. The composites exhibited pseudocapacitive behavior, with the capacitance reaching up to 185 F/g at 1 A/g and excellent capacitance retention of approximately 88.54% over 4000 charge-discharge cycles. The unique combination of rGO, PANI, and MnO2 nanoparticles in these ternary NCs offer synergistic advantages, showcasing their potential to address challenges in energy storage and gas sensing technologies.

Targeting ferroptosis by poly(acrylic) acid coated Mn3O4 nanoparticles alleviates acute liver injury

Ferroptosis, a newly characterized form of regulated cell death, is induced by excessive accumulation of lipid peroxidation catalyzed by intracellular bioactive iron. Increasing evidence has suggested that ferroptosis is involved in the pathogenesis of several human diseases, including acute liver injury. Targeted inhibition of ferroptosis holds great promise for the clinical treatment of these diseases. Herein, we report a simple and one-pot synthesis of ultrasmall poly(acrylic) acid coated Mn3O4 nanoparticles (PAA@Mn3O4-NPs, PMO), which perform multiple antioxidant enzyme-mimicking activities and can scavenge broad-spectrum reactive oxygen species. PMO could potently suppress ferroptosis. Mechanistically, after being absorbed mainly through macropinocytosis, PMO are largely enriched in lysosomes, where PMO detoxify ROS, inhibit ferritinophagy-mediated iron mobilization and preserve mTOR activation, which collectively confer the prominent inhibition of ferroptosis. Additionally, PMO injection potently counteracts lipid peroxidation and alleviates acetaminophen- and ischaemia/reperfusion-induced acute liver injury in mice. Collectively, our results reveal that biocompatible PMO act as potent ferroptosis inhibitors through multifaceted mechanisms, which ensures that PMO have great translational potential for the clinical treatment of ferroptosis-related acute liver injury.

Green Synthesis of Nanoparticles and Their Energy Storage, Environmental, and Biomedical Applications

Green synthesis offers a superior alternative to traditional methods for producing metal and metal oxide nanoparticles. This approach is not only benign and safe but also cost-effective, scalable, and straightforward, operating under ambient conditions. Notable metals and metal oxide nanoparticles, such as manganese oxides, iron oxides, silver, and gold, have been produced using various bio-reductants derived from plant extracts. These biological agents not only expedite the reduction process but also stabilize the nanoparticles, serving dual roles as reducing and capping agents. This review presents the green synthesis of nanoparticles (NPs) obtained from biogenic wastes and plant extracts. The green-synthesized nanostructured MnO2 nanoparticles are evaluated as a potential photocatalyst for water treatment and as an electrode material in lithium-ion batteries and supercapacitors. The green-derived iron oxide nanoparticles are examined as promising antioxidant, anti-inflammatory, and anti-diabetic agents. Additionally, this review discusses the green synthesis of precious metal nanoparticles, specifically silver (Ag NPs) and gold (Au NPs), highlighting their potential medical applications in areas like antiviral treatments and cancer therapy.

Intratumoral Lactate Depletion Based on Injectable Nanoparticles-Hydrogel Composite System Synergizes with Immunotherapy against Postablative Hepatocellular Carcinoma Recurrence.

Thermal ablation is a crucial therapeutic modality for hepatocellular carcinoma (HCC), but its efficacy is often hindered by the high recurrence rate attributed to insufficient ablation. Furthermore, the residual tumors following insufficient ablation exhibit a more pronounced immunosuppressive state, which accelerates the disease progression and leads to immune checkpoint blockade (ICB) resistance. Herein, evidence is presented that heightened intratumoral lactate accumulation, stemming from the augmented glycolytic activity of postablative residual HCC cells, may serve as a crucial driving force in exacerbating the immunosuppressive state of the tumor microenvironment (TME). To address this, an injectable nanoparticles-hydrogel composite system (LOX-MnO2 @Gel) is designed that gradually releases lactate oxidase (LOX)-loaded hollow mesoporous MnO2 nanoparticles at the tumor site to continuously deplete intratumoral lactate via a cascade catalytic reaction. Using subcutaneous and orthotopic HCC tumor-bearing mouse models, it is confirmed that LOX-MnO2 @Gel-mediated local lactate depletion can transform the immunosuppressive postablative TME into an immunocompetent one and synergizes with ICB therapy to significantly inhibit residual HCC growth and lung metastasis, thereby prolonging the survival of mice postablation. The work proposes an appealing strategy for synergistically combining antitumor metabolic therapy with immunotherapy to combat postablative HCC recurrence.

Photoreduction of Aqueous Protons Coupling with Alcohol Oxidation on a S-Scheme Heterojunction Photocatalyst MnO/Carbon Nitride.

Crystalline carbon nitride (CCN), derived from amorphous polymeric CN, is considered as a new generation of metal-free photocatalyst because of its high crystallinity. In order to further promote the photocatalytic performance of CCN, p-type MnO nanoparticles are in situ synthesized and merged with n-type CCN through a one-pot process to form p-n heterojunction. The formed interfacial electric field between the semiconductors with different work functions efficiently breaks the coulomb interaction between MnO and CCN. The prepared catalysts exhibit drastically increased photocatalytic hydrogen evolution (PHE) activity integrated with oxidation of alkyl and aryl alcohols under irradiation of visible light. In the aqueous solution of benzyl alcohol (BzOH), the hydrogen generation rate over MnO/CCN (39.58 µmol h-1) is nearly 7 times and 37 times that of pure CCN (5.76 µmol h-1) and CN (1.06 µmol h-1), respectively, combining with oxidation of BzOH to benzaldehyde. This work proposes an avenue for in situ construction of a novel 2D material-based S-scheme heterojunction and extends its application in solar energy conservation and utilization.

Investigating the wear performance of AZ91D magnesium composites with ZnO, MnO, and TiO2 nanoparticles

In recent decades, there has been a notable advancement in the field of bioactive, biodegradable, and biocompatible metallic materials, particularly for applications in general surgery. Among these materials, magnesium alloy-based composites have gained popularity due to their excellent biological properties and adequate strength. However, their resistance to wear is still an area that requires further investigation. Therefore, this study examines the wear properties of stir-ultrasonic-squeeze-casted magnesium (AZ91D) composites, incorporating distinct nanoparticles such as ZnO, MnO, and TiO2. The Evaluation-based Distance from Average Solution (EDAS) approach is used to determine the optimal parameters. Additionally, an Analysis of Variance (ANOVA) is conducted to identify the crucial factors influencing the responses. The effect of process factors on the wear rate and Coefficient of Friction (COF) is then investigated using response surface plots. The confirmation assessments reveal that the optimal parameter conditions for the tribo process comprise a 50.0018 N applied load, a 1.4998 m/s sliding velocity, and the AZ91D + 1% TiO2 (ATO) composite utilization. The ANOVA findings demonstrate that the applied load significantly contributes to 67.3% of the wear performance. Subsequently, after determining the optimal condition, it is observed that the ATO composite, when exposed to temperatures above 150 °C, exhibits an abrupt increase in wear rate and COF due to the degradation of grain strength and the dissolution of the β-phase within the composite.

Deciphering MnOx nanoparticles: A comprehensive analysis reveals Mn2O3 as the most cytotoxic variant in cellular systems

Manganese oxides (MnOx) nanoparticles have gained significant attention in various applications, including catalysis, energy storage, and biomedicine. However, concerns regarding their potential cytotoxicity have raised questions about their safe use in biological systems. In this study, we present a comparative investigation of the cytotoxic effect of three different MnOx nanoparticles, namely Mn3O4, Mn5O8, and Mn2O3, to evaluate their potential impact on cellular health. The structure and morphology of the synthesized nanoparticles were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) techniques. The cytotoxicity potential was assessed using PC12 cell as a model system in terms of cell viability assay, lactose dehydrogenase (LDH) release assay, and glutathione (GSH) release assay. Significant variations in cytotoxicity were observed among the different MnOx nanoparticles. Mn2O3 nanoparticles exhibited the highest cytotoxicity, followed by Mn3O4 and Mn5O8 nanoparticles, respectively. These results underscore the importance of considering nanoparticle composition in assessing their safety for potential biological applications.

Two-pronged microenvironmental modulation of metal-oxidase cascade catalysis and metabolic intervention for synergistic tumor immunotherapy

Immunotherapy is an emerging treatment modality for tumors after surgery, radiotherapy, and chemotherapy. Despite the potential for eliminating primary tumor cells and depressing cancer metastasis, immunotherapy has huge challenges including low tumor immunogenicity and undesirable immunosuppressive tumor microenvironment (TME). Herein, the two-pronged microenvironmental modulation nanoplatform is developed to overcome these limitations. Specifically, hollow mesoporous MnO2 (HM) nanoparticles with pH responsive property are prepared and modified with glucose oxidase (GOX) by amide bond, which are further loaded with a potent glutaminase inhibitor CB839 to obtain HM-GOX/CB839. Under the low pH values in TME, HM was disintegrated, thereby releasing Mn2+, GOX and CB839. On the one hand, Mn2+ can convert H2O2 that increased by GOX catalysis in tumors into highly toxic hydroxyl radicals (•OH) and further induce immunogenic cell death (ICD) through the metal-oxidase cascade catalytic reaction, enhancing immunogenicity. On the other hand, GOX and CB839 can block glycolytic and glutamine metabolism pathways, respectively, which effectively reduce the number of immunosuppressive cells and reshape TME, improving anti-tumor immune efficacy. It is demonstrated that HM-GOX/CB839 can effectively activate the body's immunity and inhibit tumor growth and metastasis, providing a potential strategy for comprehensive tumor therapy. Statement of significanceIntegrated microenvironmental modulation of metal-oxidase cascade catalysis and metabolic intervention offers a potential avenue for tumor immunotherapy. Under this premise, we constructed a two-pronged microenvironmental modulation nanoplatform (HM-GOX/CB839). On the one hand, the metal oxidase cascade could catalyze the generation of hydroxyl radicals (•OH) and induce immunogenic cell death (ICD), enhancing immunogenicity; on the other hand, metabolic intervention reprogrammed tumor microenvironment to relieve immunosuppression and thereby enhancing anti-tumor immune response. The resulting data demonstrated that HM-GOX/CB839 effectively inhibited tumor growth and metastasis, providing therapeutic potential for cancer immunotherapy.

Effects of dietary supplementation with manganese dioxide nanoparticles on growth, Mn metabolism and kidney health of yellow catfish Pelteobagrus fulvidraco

The present study was performed to investigate yellow catfish manganese (Mn) requirement with Mn dioxide nanoparticles (MnO2NPs) as Mn source, and to evaluate effects of dietary Mn on growth performance, Mn metabolism and kidney health. Using MnO2NPs as the Mn sources, six experimental diets were formulated with dietary Mn levels at 1.67, 4.35, 7.37, 13.63, 26.06 and 50.37 mg Mn/kg diet, respectively, and fed to yellow catfish for 8 weeks. Yellow catfish growth performance and feed intake were the highest in the group of 13.63 mg Mn/kg diet, and the lowest in the group of 1.67 mg Mn/kg diet; and the feed conversion rate showed opposite trend with growth performance. Dietary Mn addition increased Mn content in the whole body, kidney and serum. The mRNA abundances of dmt1, zip8 and znt10 increased with the increase of dietary Mn level. Yellow catfish fed high dietary MnO2NPs level had higher mRNA abundances of dynamin1, dynamin2, cav1, cltc and eps15. Dietary Mn excess damaged the kidney histology. Yellow catfish fed the 13.63 mg Mn/kg diet had higher T-AOC, T-SOD, Mn-SOD, CAT activities, and mRNA levels of sod1, sod2 and cat (antioxidant response), but lower mRNA abundances of grp78, ire1, perk and atf4 (endoplasmic reticulum stress), tnfα, il1β and il6 (inflammatory response). The broken-line analysis of WG and the linear regression of whole-body Mn retention against dietary Mn levels showed that optimal Mn requirement was 12.57 mg Mn/kg diet and 8.33 mg Mn/kg diet, respectively, with MnO2NPs as Mn source. For the first time, we explored the effects of dietary MnO2 nanoparticles on growth performance, Mn uptake and metabolism, antioxidant responses, endoplasmic reticulum stress and inflammatory responses of the kidney, and determined the optimal dietary Mn requirement of yellow catfish fed MnO2 nanoparticles-added diet.

High performance flexible lithium-ion battery anodes: Carbon nanotubes bridging bamboo-shaped carbon-coated manganese oxide nanowires via carbon welding

Free-standing electrodes will significantly improve the specific capabilities of LIBs and reduce manufacturing costs; importantly, the introduction of the carbon protective layer can solve the problem of capacity attenuation. Herein, a novel closely crosslinked three-dimensional carbon nanotubes (CNTs) network bridge bamboo-shaped carbon-coated MnO (CCMC) flexible film anode is designed. For this design, the carbon layer can provide high electrical conductivity while buffering the volume changes of the MnO nanoparticles during repeated cycling. Meanwhile, the CNTs are also highly conductive and bridged between bamboo-shaped carbon-coated MnO (MC) to support the entire structure, effectively improving the tensile strength and structural stability of CCMC. In addition, the CCMC flexible film electrode as the anode material of flexible LIBs, does not use conductive agent, binder and collector, shows excellent electrochemical properties, including a high-rate capability of 909 mAh g−1 at 0.1 A g−1 and 406 mAh g−1 at 5.0 A g−1, and a long cycling stability (411 mAh g−1 at 0.5 A g−1 after 1000 cycles).