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Ting-Ting Zhang, Cong-Hui Xu, Wei Zhao, Yu Gu, Xiang-Ling Li, Jing-Juan Xu, Hong-Yuan Chen
Development of tumor microenvironment responsive and modulating theranostic nano-systems is of great importance for specific and efficient cancer therapy. Herein, we report a redox-sensitive nanoagent combining manganese dioxide (MnO2 ) and gold nanoshell coated silicon nanoparticles for synergistic chemo-photothermal therapy of hypoxia solid tumors. In highly reducing tumor tissues, the outer MnO2 nanosheet with the loaded drug would be dissociated by intracellular glutathione (GSH), resulting in on-demand drug release, as well as generating Mn2+ ions which provided high contrast magnetic resonance imaging (MRI), and fluorescence imaging (FI) in vitro and in vivo ...
September 7, 2018: Chemical Science
Lei Wang, Mengya Niu, Cuixia Zheng, Hongjuan Zhao, Xiuxiu Niu, Li Li, Yujie Hu, Yingjie Zhang, Jinjin Shi, Zhenzhong Zhang
Sonodynamic therapy (SDT) always causes tumor hypoxia aggravation which can induce malignant cell proliferation and drug resistance. To overcome these disadvantages, a cascaded drug delivery system (Lipo/HMME/ACF@MnO2 -AS1411) is constructed for synergistic enhanced sonodynamic therapy. First, hematoporphyrin monomethyl ether (HMME) and acriflavine (ACF) are encapsulated in the lipid layers and the inner aqueous cores of the liposomes, respectively. Then the ultrathin manganese dioxide (MnO2 ) nanosheets are coated on the surface of the liposomes by using KMnO4 and polyethylene glycol through "one step reduction and modification" method...
October 10, 2018: Advanced Healthcare Materials
Davide Barreca, Filippo Gri, Alberto Gasparotto, Giorgio Carraro, Lorenzo Bigiani, Thomas Altantzis, Boštjan Žener, Urška Lavrenčič Štangar, Bruno Alessi, Dilli Babu Padmanaban, Davide Mariotti, Chiara Maccato
Supported MnO2-based nanomaterials were fabricated on fluorine-doped tin oxide substrates using plasma enhanced-chemical vapor deposition (PE-CVD) between 100 °C and 400 °C, starting from a fluorinated Mn(ii) diamine diketonate precursor. Growth experiments yielded β-MnO2 with a hierarchical morphology tuneable from dendritic structures to quasi-1D nanosystems as a function of growth temperature, whose variation also enabled a concomitant tailoring of the system fluorine content, and of the optical absorption and band gap...
October 10, 2018: Nanoscale
Qijun Zong, Qichong Zhang, Xue Mei, Qiulong Li, Zhenyu Zhou, Dong Li, Mingyuan Chen, Feiyang Shi, Juan Sun, Yagang Yao, Zengxing Zhang
Flexible fiber-shaped supercapacitors hold promising potential in the area of portable and wearable electronics. Unfortunately, their general application is hindered by the restricted energy densities due to low operating voltage and small specific. Herein, an all-solid-state fiber-shaped asymmetric supercapacitor (FASC) possessing ultrahigh energy density is reported, in which the positive electrode was designed as Na-doped MnO2 nanosheets on carbon nanotube fibers (CNTFs) and the negative electrode as MoS2 nanosheets coated CNTFs...
October 9, 2018: ACS Applied Materials & Interfaces
Lei Fu, Katsumi Shozugawa, Motoyuki Matsuo
The oxidation of antimony (III) in soils was studied using X-ray absorption fine structure (XAFS) spectra. An andosol soil sample and artificial soil samples (SiO2 blended with iron (III) hydroxide and manganese (IV) oxide) were used herein. After adding antimony (III) oxide to all soil samples, the oxidation process was observed by recording the XAFS spectra of Sb K-edge, Fe K-edge, and Mn K-edge. The results indicated that manganese (IV) oxide played an important role in the oxidation of Sb(III); however iron (III) hydroxide was not directly related to the reaction...
November 2018: Journal of Environmental Sciences (China)
Dheeraj Mondal, Biplab Kumar Paul, Santanu Das, Debopriya Bhattacharya, Debopriyo Ghoshal, Papiya Nandy, Kaustuv Das, Sukhen Das
Because of the superior optical and electrical properties, copper impregnated size tuneable high-temperature stable manganese dioxide semiconductor quantum dots (SQDs) have been successfully synthesized by a modified chemical synthesis technique. Their size-dependent dielectric properties, semiconducting properties, and current-voltage (I-V) characteristics have been investigated. X-ray diffraction pattern and Raman spectra (RS) confirmed that the required phase is present. Due to the different sintering temperature tuneable size of SQDs has been found and confirmed by high resolution transmission electron microscopy (HRTEM)...
October 5, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Seok Bok Hong, Jae-Min Jeong, Heon Gyu Kang, Donghyuk Seo, Younghyun Cha, Hyeonyeol Jeon, Geun Young Lee, Mobina Irshad, Do Hyun Kim, Sung Yeon Hwang, Jung Won Kim, Bong Gill Choi
The integration of metal oxides and carbon materials provides a great potential for enhancing the high energy and power densities of supercapacitors, but the rational design and scalable fabrication of such composite materials still remain a challenge. Herein, we report a fast, scalable, and one-pot hydrodynamic synthesis for preparing ion conductive and defect-free graphene from graphite and MnO2 /graphene nanocomposites. The use of this hydrodynamic method using Taylor-Couette flow allows us to efficiently fast shear-exfoliate graphite into large quantities of high-quality graphene sheets...
October 5, 2018: ACS Applied Materials & Interfaces
V Sabna, Santosh G Thampi, S Chandrakaran
This is an investigation on oxidative degradation of rhodamine B (RhB) by manganese dioxide (MnO2 ) nanorods synthesized by redox co-precipitation method. Field emission scanning electron microscopy of MnO2 nanorods at an electron voltage of 10 kV revealed a rod-like morphology for the synthesized nanoparticles. Fourier transform infrared spectra exhibited characteristic peaks of MnO2 . Surface area of MnO2 nanorods was 277 m2 /g. Effect of various parameters like initial concentration and pH of RhB solution, time of contact between MnO2 nanorods and RhB, dosage of MnO2 , and stirring speed on decolouration of RhB was evaluated in batch experiments...
October 2018: Journal of Water and Health
Zhenqing Shi, Shimeng Peng, Pei Wang, Qian Sun, Yujun Wang, Guining Lu, Zhi Dang
Understanding the kinetic reactions of antimony (Sb) at the MnO2-water interface is essential for predicting the dynamic behavior of Sb in soil environments. In this study, we developed a quantitative model for assessing the coupling between Sb(iii) oxidation and Sb(iii)/Sb(v) adsorption/desorption kinetics and the role of each individual reaction process in controlling the overall reaction rates. Based on our modeling results, Sb(iii) oxidation rates were very fast at the early stages of the reactions and may significantly slow down with time, and Sb(iii) and Sb(v) showed different adsorption behavior on δ-MnO2...
October 4, 2018: Environmental Science. Processes & Impacts
Fatma A M Abdel-Aal, Azza H Rageh, Mohamed I Said, Gamal A Saleh
A novel, simple and sensitive electrochemical method for the determination of ledipasvir (LED), the newly FDA approved Hepatitis C antiviral drug was developed and validated using ε-MnO2 -modified graphite electrode. Two different MnO2 polymorphs (γ- and ε-MnO2 nanoparticles) were synthesized and characterized using X-ray powder diffraction (XRD), Fourier transform infrared (FTIR), energy dispersive X-ray (EDX) and thermogravimetric analysis (TGA). Surface area measurements show that ε-MnO2 NPs have large surface area of 345 m2 /g, which is extremely high if compared to that of γ-MnO2 NPs (38 m2 /g)...
December 14, 2018: Analytica Chimica Acta
Zhi-Ling Song, Xin Dai, Mengru Li, He Teng, Zhen Song, Dexun Xie, Xiliang Luo
Near infrared (NIR) emitting semiconductor quantum dots can be excellent fluorescent nanoprobes, but the poor biodegradability and potential toxicity limits their application. The authors describe a fluorescent system composed of graphene quantum dots (GQDs) as NIR emitters, and novel MnO2 nanoflowers as the fluorescence quenchers. The system is shown to be an activatable and biodegradable fluorescent nanoprobe for the "turn-on" detection of intracellular glutathione (GSH). The MnO2 -GQDs nanoprobe is obtained by adsorbing GQDs onto the surface of MnO2 nanoflowers through electrostatic interaction...
October 1, 2018: Mikrochimica Acta
Marius Gheju, Ionel Balcu
This study aims to provide new knowledge regarding the effect of MnO2 co-presence on efficiency of Cr(VI) removal with Fe(0). Non-disturbed batch experiments (≤40 days) were conducted using two types of Fe(0) (milli- and micro-sized), two Cr(VI) concentrations (5 and 100 mg/L), in three different systems ("Fe(0) only", "MnO2 only", and "Fe(0) + MnO2 "), at an initial pH value of 6.9. Compared to "Fe(0) only" system, the efficiency and rate of Cr(VI) removal were highly promoted in "Fe(0) + MnO2 " system; moreover, while for the "Fe(0) only" system removal of Cr(VI) was severely hindered by increasing Cr(VI) concentration, in "Fe(0) + MnO2 " system comparable high efficacies were noticed both at low and high concentration...
September 21, 2018: Chemosphere
En Shi, Zhenlan Xu, Xiaoxia Zhang, Xuezhi Yang, Qian Liu, Hangjun Zhang, Andreas Wimmer, Lingxiangyu Li
Stability of silver sulfide nanoparticle (Ag2 S-NP) in the environment has recently drawn considerable attention since it is associated with environmental risk. Although the overestimated stability of Ag2 S-NP in aqueous solution has already been recognized, studies on transformation of Ag2 S-NP in environmental water are still very scarce. Here we reported that Ag2 S-NP could undergo dissolution by manganese(IV) oxide (MnO2 ), an important naturally occurring oxidant in the environment, even in environmental water, although the dissolved silver would probably be adsorbed onto the particles (>0...
September 22, 2018: Environmental Pollution
Maoqiang Chi, Yun Zhu, Liwei Jing, Ce Wang, Xiaofeng Lu
Recently, nanomaterials-based oxidase-like artificial enzymes have attracted much attention due to their unique catalytic efficiency, high environmental stability and low-cost. In this study, we for the first time show the application of polyaniline (PANi)-MnO2 hybrid nanowires for oxidase mimicking. The PANi-MnO2 hybrid nanowires are prepared via a redox reaction between PANi nanowires and KMnO4 . The as-prepared PANi-MnO2 hybrid nanowires exhibit an enhanced oxidase-like catalytic activity compared with individual PANi nanowires and MnO2 alone due to the synergistic catalytic effect between the two components...
January 1, 2019: Talanta
Mir Reza Majidi, Fatemeh Shahbazi Farahani, Mirghasem Hosseini, Iraj Ahadzadeh
In this work, low cost α-MnO2 nanowires and α-MnO2 nanowires supported on carbon Vulcan (α-MnO2 /C) have been synthesized via a simple and facile hydrothermal method for application in microbial fuel cells. The prepared samples have been characterized by X-ray diffraction (XRD), Raman spectroscopy and field emission scanning electron microscopy (FE-SEM). Electrocatalytic activities of the samples have been evaluated by means of cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) in a neutral phosphate buffer solution...
September 15, 2018: Bioelectrochemistry
Peng Huang, Ming Zhao, Bo Jin, Huan Li, Zhi Zhu, Lixue Jiang, Qing Jiang
With the depletion of fossil energy and rapid development of electronic equipment, the commercial lithium-ion batteries (LIBs) do not meet the current energy demand. There is an urgent need to develop novel LIBs with high capacity, long life, and low cost. In this work, we design and synthesize a MnCo2O4@NC@MnO2 three-layered core-shell octahedron with good electrochemical performance using binary transition metal oxide (MnCo2O4), N-doped carbon (NC), and high-capacity manganese oxide (MnO2). The three-layered structure is effective in relieving the volume expansion, improving the electronic conductivity, and strengthening the structural stability...
September 25, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Aparajita Das, Sathish Deshagani, Raj Kumar, Melepurath Deepa
Photo-supercapacitors (PSCs) combine functions of energy harvesting and storage in a single device, and in this study, a new architecture for a PSC is designed and implemented. Cadmium sulfide (CdS) quantum dots (QDs)/hibiscus (hb) dye co-sensitized TiO2 is used as the solar cell. Poly(3,4-ethylenedioxypyrrole) (PEDOP)@manganese dioxide (MnO2) is employed as the counter electrode (CE) for the solar cell, and also as the electrodes for the symmetric supercapacitor. The two ends of a long flat current collector support two spatially separated PEDOP@MnO2 coatings, which serve as the CEs for the TiO2/hb/CdS photoanode and yet another PEDOP@MnO2 electrode in sandwich configurations...
September 25, 2018: ACS Applied Materials & Interfaces
Zhi Song, Yu-Long Ma, Cong-Er Li
The object of this study was to remove the tetracycline (TC) residue in pharmaceutical wastewater after flocculation treatment. MnO2 /graphene nanocomposite was synthesized by an in situ hydrothermal method and its TC removal rate was up to 99.4%. This nanocomposite had excellent water solubility. More importantly, the introduction of MnO2 nanorods allowed the avoidance of excessive stacking of treated graphene sheets during the adsorption process, which made the TC molecules to have more opportunities to make contact with the adsorbents...
September 19, 2018: Science of the Total Environment
Ya Cheng, Tinglin Huang, Lijie Cheng, Yuankui Sun, Laisheng Zhu, Ye Li
Two types of filter media in groundwater treatment were conducted for a comparative study of surface structure and catalytic performance. Natural filter media was adopted from a conventional aeration-filtration groundwater treatment plant, and active filter media as a novel and promising filter media was also adopted. The physicochemical properties of these two kinds of filter media were characterized using numerous analytical techniques, such as X-Ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS) and Zeta potential...
October 2018: Journal of Environmental Sciences (China)
Dianping Tang, Youxiu Lin, Qian Zhou
An enzyme-linked immunoassay is described for the fluorometric determination of aflatoxin B1 (AFB1 ). It is based on the use of carbon dots (CDs) synthesized by using Litchi chinensis as the carbon source via a hydrothermal method. The CDs were modified with MnO2 nanosheets upon which their blue fluorescence (with excitation/emission peaks at 340/425 nm) is quenched. In the presence of AFB1 , a competitive immunoreaction takes place between (1) AFB1 conjugated to bovine serum albumin and deposited in the wells of a microplate, and (2) antibody against AFB1 and labeled with alkaline phosphatase (ALP)...
September 21, 2018: Mikrochimica Acta
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