MnO2 NPs Research Articles

Smart Tumor Microenvironment‐Responsive Nanotheranostic Agent for Effective Cancer Therapy

AbstractThe tumor microenvironment (TME), which includes acidic and hypoxic conditions, severely impedes the therapeutic efficacy of antitumor agents. Herein, MnO2‐loaded, bovine serum albumin, and PEG co‐modified mesoporous CaSiO3 nanoparticles (CaM‐PB NPs) are developed as a nanoplatform with sequential theranostic functions for the engineering of TME. The MnO2 NPs generate O2 in situ by reacting with endogenous H2O2, relieving the hypoxic state of the TME that further modulates the cancer cell cycle status to S phase, which improves the potency of co‐loaded S phase‐sensitive chemotherapeutic drugs. After the hypoxia relief, CaM‐PB can sustainably release drugs due to the enlarged pores of mesoporous CaSiO3 in the acidic TME, preventing the drug pre‐leakage into the blood circulation and insufficient drug accumulation at tumor sites. Moreover, the Mn2+ released from the MnO2 NPs at tumor sites can potentially serve as a diagnostic agent, enabling the identification of tumor regions by T1‐weighted magnetic resonance imaging during therapy. In vivo pharmacodynamics results demonstrate that these synergetic effects caused by CaM‐PB NPs significantly contribute to the inhibition of tumor progression. Therefore, the CaM‐PB NPs with sequential theranostic functions are a promising system for effective cancer therapy.

Euphorbia heterophylla L. Leaf Extract-Mediated Synthesis of MnO2 Nanoparticles and Its Characterization

Abstract Manganese oxide nanoparticles (MnO2 NPs) prepared by green synthesis method using Euphorbia heterophylla L. leaves extract (ELE) had been reported. Functional groups, particle size distribution, crystallinity structure, bandgap energy and morphology of MnO2 NPs were also investigated. Chemical bonding of Mn-O was confirmed by Fourier- Transform Infrared (FTIR) at 559 cm-1 wave number. The particle size of MnO2 NPs measured by Particle Size Analyzer (PSA) instrument was about 56.68 nm. Characterization using X- Ray Diffraction (XRD) indicated diffraction peaks of MnO2 NPs at 28.75o; 37.41; 42.80o; 56.74o; 59.97o; 64.95o; 72.42o and 72.63o, these peaks corresponded to the miller indices of 110; 101; 111; 211; 220; 002; 301 and 112, respectively. Bandgap energy of MnO2 NPs was 2.85 eV confirmed by UV-Vis DRS spectrophotometer. The morphology of MnO2 NPs was confirmed by Scanning Electron Microscope-Energy Dispersive X-Ray indicated the ratio of composition Mn and O atom was 34,60 and 65,40 % and Transmission Electron Microscope showed that MnO2 NPs had irregular shape

Construction of effective electrochemical sensor for the determination of quinoline yellow based on different morphologies of manganese dioxide functionalized graphene

Developing simple and accurate QY detection methods is of great significant importance in ensuring food safety including drinks. Manganese dioxide nanoparticles (MnO2 NPs) with different morphologies were synthesized by hydrothermal method. Manganese dioxide/graphene (MnO2/GR) nanocomposites were directly prepared on the surface of glassy carbon electrode (GCE) by electrochemical reduction. The materials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The effects of nano-MnO2 with different morphologies on the performance of quinoline yellow (QY) detection was investigated. The experimental findings revealed that MnO2 nanorods (MnO2 NRs) had better properties than both MnO2 nanowires (MnO2 NWs) and MnO2 nanotubes (MnO2 NTs). Under optimal experimental conditions, a good linear relationship between peak current of QY on GR/MnO2 NRs/GCE and concentrations ranging between 0.1 μM˜6.0 μM and 6.0 μM˜60 μM were observed, and 0.04 μM was the detection limit. The fabricated sensor was successfully tested to detect QY in soft drinks.

Cascade catalytic nanoplatform for enhanced starvation and sonodynamic therapy

Background: Sonodynamic therapy (SDT) has emerged as an alternative to the traditional treatments of cancer. However, the oxygen consumption induced by SDT and glucose oxidase (GOx) mediated starvation therapy would worsen the hypoxic tumor environment, which further impeded therapeutic efficacy. Purpose: To develop a nanoplatform and investigate its anti-cancer mechanism for enhanced starvation and SDT.Methods: We constructed a cascade catalytic nanoplatform based on GOx modified the mesoporous MnO2 NPs loaded with hematoporphyrin monomethyl ether (HMME), which were designated as GOx-MnO2/HMME. We characterized them for their catalytic activity, and investigate the magnetic resonance imaging and anti-tumor efficiency in vitro and in vivo.Results: MnO2 NPs with catalase-like activity could oxidize H2O2 under acid condition to produce O2, which not only in turn was supplied to the glucose-depletion reaction for an efficient starvation therapy, but also enhanced the 1O2 generation for HMME mediated SDT effect. In addition, the released Mn2+ ions in the system were able to enhance the MRI signal. Both in vitro and in vivo experiments suggested the cascade catalytic-therapeutic effect between GOx, MnO2 NPs and HMME, demonstrating the enhanced starvation and SDT.

Cornstalk-based manganese dioxide nanoparticles for methylene blue decontamination

Cornstalk-based MnO2 nanoparticles (MnO2 NPs) were synthesized from KMnO4 through an in situ redox reaction. The synthesis was performed under an open system and did not need complicated apparatus, giving its advantages of easy operation, low cost and green synthesis. Combining the adsorption capacity with oxidation activity, the as-prepared cornstalk-based MnO2 NPs were applied to methylene blue (MB) decontamination. It was demonstrated that the removal efficiency was 79.88% in 60[Formula: see text]min by adsorption in water and reached up to 95.16% in pH [Formula: see text] 3 buffer with the help of oxidation. Most importantly, the decontamination materials could be separated simply by taking them out from MB solutions during the monitoring process or after treatment, avoiding the fussy centrifugation or filtration. This advantage endows the cornstalk-based MnO2 NPs superiority and would raise concerns in water decontamination.

Direct electro-synthesis of MnO2 nanoparticles over nickel foam from spent alkaline battery cathode and its supercapacitor performance

Abstract This work reports the recovery of manganese ions from spent primary alkaline battery (PAB) cathode, subsequent anodic electro-synthesis of MnO2 nanoparticles on Ni foam (MnO2 NPs/Ni foam) for supercapacitors. The as-fabricated MnO2 NPs/Ni foam is characterized by common optical and surface analytical techniques. The X-ray diffraction (XRD) of MnO2 NPs/Ni foam matches well with γ-MnO2 NPs pattern and hence the synthesized MnO2 NPs mainly exist in γ-phase. The synthesized MnO2 NPs are mostly in spherical cluster shape with an average size of 15 nm, inferred from the scanning electron microscopic (SEM) images. The X-ray photoelectron spectroscopy (XPS) result reveals that, synthesized MnO2 NPs embraces with two different oxidation states such as 4+ (MnO2) and 3+ (MnOOH). The MnO2 NPs/Ni foam delivers a maximum specific capacity of 549 F/g at the scan rate of 5 mV/s in three electrodes aqueous K2SO4 system. Further, the two electrode asymmetric supercapacitor device is constructed with MnO2 NPs/Ni foam as a positive and commercial graphene nanoplatelets coated Ni foam (GNP/Ni foam) as a negative electrode. The assembled supercapacitor device yields a maximum specific capacitance of 105 F/g at 5 mV/s, which achieves a maximum energy density of 14.7 Wh/kg at the power density of 748.9 W/kg between 0 and 1.5 V of working potential. This effort may pave the way for recovery and utilization of spent PAB cathode materials for energy storage devices.

Manganese dioxide nanoparticles/activated carbon composite as efficient UV and visible-light photocatalyst.

Manganese dioxide nanoparticles/activated carbon (MnO2/AC) composites and manganese dioxide nanoparticles (MnO2 NPs) are prepared through chemical reduction method. Morphological study shows that MnO2 NPs had cylindrical and spherical shape. The morphological study also revealed that MnO2 NPs were well dispersed on AC while neat Mn NPs present both in dispersed and in agglomerated form. The FT-IR study confirms the synthesis of MnO2 NPs. Zetasizer study presented that the Mn NPs had uniform size and below 100nm in size and had zeta potential of - 20mV, which represent its stability in the suspension form. The synthesized Mn/AC composite and Mn NPs were utilized as photocatalysts for the photodegradation of Congo red (CR) dye. The degradation study shows that MnO2/AC composite degraded CR dye more efficiently than MnO2 NPs under UV and normal light irradiation. The efficient degradation of dye by Mn/AC composite is due to the synergistic effect between dye adsorption on AC and rapid photodegradation by supported MnO2 NPs. The results revealed that Mn/AC composite degraded about 98.53% of CR dye within 5min while MnO2 NPs degraded 66.57% of dye within the same irradiation time. The recycled catalyst also significantly degraded dye which verifies its sustainability. The effect of catalyst dosage and initial dye concentration was conducted. The degradation rate of dye was found drastically faster in tap water (in presence of catalyst), which might be due to the presence of various mineral ions in the tap water.

Dual role of BSA for synthesis of MnO2 nanoparticles and their mediated fluorescent turn-on probe for glutathione determination and cancer cell recognition.

A MnO2 nanoparticle (MnO2 NP)-mediated fluorescent turn-on probe for sensitively and selectively detecting glutathione (GSH) and recognizing cancer cells was established in this work. MnO2 NPs were synthesized simply and quickly through an in situ redox reaction by mixing bovine serum albumin (BSA) and KMnO4, in which BSA served the dual roles of template and reductant. It was found that the MnO2 NPs served as an effective energy acceptor and quenched the fluorescence intensity of carbon dots (CDs), owing to the fluorescence resonance energy transfer (FRET) process. Further, the addition of GSH triggered the decomposition of MnO2, breaking the FRET between MnO2 NPs and CDs and thus restoring the fluorescence intensity of CDs. Based on this mechanism, quantitative determination of GSH was performed. Under optimal conditions, a satisfactory linear range of 0.05-90 μM and limit of detection of 39 nM were obtained, and GSH content in human serum samples was detected. Moreover, taking advantage of the higher levels of GSH in cancer cells than in normal cells, the MnO2 NP-CD probe was applied to distinguish SMMC-7721 cancer cells from L02 normal cells. The FRET was interrupted by GSH in cancer cells, and strong fluorescence was observed. This work provides a facile approach for synthesizing MnO2 NPs, and this rapid, low-cost method with no need for reductants makes synthesis green and convenient. The MnO2 NP-mediated fluorescent turn-on response to GSH could improve the MnO2 nanomaterial-based biochemical analysis applications.

Different cytotoxic and apoptotic responses of MCF-7 and HT1080 cells to MnO2 nanoparticles are based on similar mode of action

Manganese (IV) oxide nanoparticles (MnO2 NPs) are increasingly used in numerous applications. Multiple applications of MnO2 NPs, however, increase the human exposure and thus potential risk related to their toxicity. There is little information regarding the toxicity mechanisms of MnO2 NPs in human cells. In this study, we explored the toxic potential of MnO2 NPs in human breast cancer epithelial (MCF-7) and human fibrosarcoma epithelial (HT1080) cells in order to examine whether epithelial cells of different origins showed similar responses. Results demonstrated that MnO2 NPs induced cell viability reduction and membrane damage in both MCF-7 and HT1080 cells in a dose-dependent manner. MnO2 NPs were also found to induce pro-oxidants generation and antioxidants depletion in both cells. We further observed that MnO2 NPs induce apoptosis in both MCF-7 and HT1080 cells evident by altered regulation of apoptotic genes (p53, bax & bcl-2), cell cycle arrest and low mitochondrial membrane potential. Interestingly, we noticed that HT1080 cells were more susceptible to MnO2 NPs exposure than those of MCF-7 cells. This could be due to higher level of MnO2 NPs uptake into HT1080 cells as compared to MCF-7 cells. However, the mechanism of toxicity induced by MnO2 NPs in both MCF-7 and HT1080 cells was highly similar. This study warrants further research to delineate the underlying mechanisms of MnO2 NPs toxicity at in vivo level.

Green synthesis, characterisation, and photocatalytic activity of manganese dioxide nanoparticles

In this work, a simple, efficient and eco-friendly procedure for the green synthesis of manganese dioxide nanoparticles (MnO2 NPs) by Yucca gloriosa leaf extract is described. The MnO2 NPs were synthesised using Y. gloriosa leaf extract and curcumin as reducing and stabilising agents, respectively. Fourier-transform infrared spectra revealed the involvement of the plant extract in the formation of MnO2 NPs. The ultraviolet–visible absorption spectra of the synthesised MnO2 NPs exhibited absorption peaks at 410 nm, which were attributed to the band gap of the MnO2 NPs. Crystal phase identification of the MnO2 NPs was characterised by X-ray diffraction analysis and the formation of crystalline MnO2 NPs has been confirmed. Also, the X-ray diffraction pattern displayed that the average size of MnO2 NPs was about 80 nm. Furthermore, field emission scanning electron microscopy analysis showed that the synthesised MnO2 NPs have a spherical shape. MnO2 NPs have photocatalytic activities for the dye degradation in the visible light region. The photocatalytic activities for the dye degradation of MnO2 NPs were evaluated using Acid Orange as an organic contaminant.

ε-MnO2-modified graphite electrode as a novel electrochemical sensor for the ultrasensitive detection of the newly FDA approved Hepatitis C antiviral drug ledipasvir

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). In addition, a comprehensive study of the difference in the electrochemical behavior of LED while using pencil graphite electrode (PGE) modified with either γ- or ε-MnO2 NPs is carried out. It was found that surface area and percentage of surface hydroxyls of MnO2 NPs are the key factors governing the sensitivity of the fabricated electrode toward the oxidation of the positively charged LED. Scanning electron microscopy (SEM) was employed to investigate the morphological shape of MnO2 NPs and the surface of the bare and modified electrodes. Moreover, cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were used for the surface analysis of the modified electrodes. Based on the obtained results, ε-MnO2/PGE was applied as a selective and sensitive electrode for determination of LED. Under the optimized experimental conditions, ε-MnO2/PGE provides a linear response over the concentration range of 0.025–3.60 μmol L−1 LED with a low limit of detection, which was found to be 5.10 nmol L−1 (4.50 ng mL−1) for the 1st peak and 9.20 nmol L−1 (8.10 ng mL−1) for the 2nd one. In addition, the oxidation behavior of LED is discussed with a full investigation of the oxidized product using FT-IR and LC/MS. The fabricated sensor exhibits a good precision, selectivity and stability and was applied successfully for the determination of LED in its tablets and real rat plasma samples with a good recovery using a simple extraction technique.

MnO2 Nanoparticles and Carbon Nanofibers Nanocomposites with High Sensing Performance Toward Glucose

By combining the advantages of manganese dioxide nanoparticles (MnO2 NPs) and carbon nanofibers (CNFs), a biosensing electrode surface as a high-performance enzyme biosensor is designed in this work. MnO2 NPs and CNFs nanocomposites (MnO2–CNFs) were prepared by using a simple hydrothermal method and then were characterized by scanning electron microscopy, powder X-ray diffraction, fourier transform infrared spectroscopy, energy dispersive spectrometry and electrochemisty. The results showed that MnO2 NPs are uniformly attached to the surface of CNFs. Meanwhile, the MnO2–CNFs nanocomposites as a supporting matrix can provide an efficient and advantageous platform for electrochemical sensing applications. On the basis of the improved sensitivity of MnO2–CNFs modified electrode toward H2O2 at low overpotential, a MnO2–CNFs based glucose biosensor was fabricated by monitoring H2O2 produced by an enzymatic reaction between glucose oxidase and glucose. The constructed biosensor exhibited a linear calibration graph for glucose in a concentration range of 0.08–4.6 mM and a low detection limit of 0.015 mM. In addition, the biosensor showed other excellent characteristics, such as high sensitivity and selectivity, short response time, and the relative low apparent Michaelis–Menten constant. Analysis of human urine spiked with glucose at different concentration levels yielded recoveries between 101.0 and 104.8%.

Fabrication of novel electrochemical sensors based on modification with different polymorphs of MnO2 nanoparticles. Application to furosemide analysis in pharmaceutical and urine samples.

A novel MnO2 nanoparticles/chitosan-modified pencil graphite electrode (MnO2 NPs/CS/PGE) was constructed using two different MnO2 polymorphs (γ-MnO2 and ε-MnO2 nanoparticles). X-ray single phases of these two polymorphs were obtained by the comproportionation reaction between MnCl2 and KMnO4 (molar ratio of 5 : 1). The temperature of this reaction is the key factor governing the formation of the two polymorphs. Their structures were confirmed by powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) and energy dispersive X-ray (EDX) analysis. Scanning electron microscopy (SEM) was employed to investigate the morphological shape of MnO2 NPs and the surface of the bare and modified electrodes. Moreover, cyclic voltammetry and electrochemical impedance spectroscopy (EIS) were used for surface analysis of the modified electrodes. Compared to bare PGE, MnO2 NPs/CS/PGE shows higher effective surface area and excellent electrocatalytic activity towards the oxidation of the standard K3[Fe(CN)6]. The influence of different suspending solvents on the electrocatalytic activity of MnO2 was studied in detail. It was found that tetrahydrofuran (THF) is the optimum suspending solvent regarding the peak current signal and electrode kinetics. The results reveal that the modified γ-MnO2/CS/PGE is the most sensitive one compared to the other modified electrodes under investigation. The modified γ-MnO2/CS/PGE was applied for selective and sensitive determination of FUR. Under the optimized experimental conditions, γ-MnO2/CS/PGE provides a linear response over the concentration range of 0.05 to 4.20 μmol L−1 FUR with a low limit of detection, which was found to be 4.44 nmol L−1 (1.47 ng mL−1) for the 1st peak and 3.88 nmol L−1 (1.28 ng mL−1) for the 2nd one. The fabricated sensor exhibits a good reproducibility and selectivity and was applied successfully for the determination of FUR in its dosage forms and in spiked urine samples with good accuracy and precision.

Redox-Responsive Manganese Dioxide Nanoparticles for Enhanced MR Imaging and Radiotherapy of Lung Cancer.

In this study, we synthesized manganese dioxide nanoparticles (MnO2 NPs) stabilized with biocompatible polymers (polyvinylpyrrolidone and polyacrylic acid) and analyzed their effect on non-small cell lung cancer (NSCLC) cells with or without gefitinib resistance in vitro. MnO2 NPs showed glutathione (GSH)-responsive dissolution and subsequent enhancement in magnetic resonance (MR) imaging. Of note, treatment with MnO2 NPs induced significant cytotoxic effects on NSCLC cells, and additional dose-dependent therapeutic effects were obtained upon X-ray irradiation. Normal cells treated with MnO2 NPs were viable at the tested concentrations. In addition, increased therapeutic efficacy could be achieved when the cells were treated with MnO2 NPs in hypoxic conditions. Therefore, we conclude that the use of MnO2 NPs in MR imaging and combination radiotherapy may be an efficient strategy for the imaging and therapy of NSCLC.

Manganese dioxide nanoparticle-based colorimetric immunoassay for the detection of alpha-fetoprotein

An immunoassay has been developed for the determination of alpha-fetoprotein (AFP). It is based (a) on the use of a detection reaction mediated by manganese dioxide nanoparticles (MnO2 NPs) because their good stability at room temperature, and (b) on tyramine signal amplification (TSA). The MnO2 NPs acts as an artificial peroxidase that causes the conversion of TMB to give a colored product, and the tyramine-triggered reaction is used for signal amplification to improve the detection limit. Combined with immuno-magnetic separation and enrichment, the response of this AFP immunoassay is linear from 6.25–400 ng mL−1, with a detection limit of 22 pg mL−1 (S/N = 3). This immunoassay was successfully applied to the quantification of AFP in serum samples, and gave excellent accuracy compared with the clinical results from a local hospital. The LOD and stability of this assay are better than those of the standard horseradish peroxidase-based ELISA. The strategy presented here is conceived to have a wider scope in that it may be extended to various other immunoassays.

Polythiophene supported MnO2 nanoparticles as nano-stabilizer for simultaneously electrostatically immobilization of d-amino acid oxidase and hemoglobin as efficient bio-nanocomposite in fabrication of dopamine bi-enzyme biosensor

A novel, highly selective and sensitive voltammetric bi-enzyme biosensor for sensing dopamine (DA), in presence of H2O2 which resulted as d-alanine enzymatic oxidation, was fabricated on the basis of simultaneously electrostatically immobilization of d-amino acid oxidase (DAAO) and hemoglobin (Hb) on MnO2 nanoparticles (MnO2 NPs) enriched poly thiophene (PTh). Cyclic voltammetry (CV), technique was applied for electropolymerization of thiophene on glassy carbon electrode (GCE) surface and MnO2 NPs dispersed on PTh network by soaking PTh/GCE in potassium permanganate (KMnO4) solution. Excellent catalytic properties and large surface area of MnO2 NPs/PTh composite caused it was used as an enzymes immobilization host in this developed bi-enzyme biosensor. The developed biosensor was characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and CV. The performance of the modified bi-enzyme biosensor was investigated in terms of its response time, detection limit, sensitivity, stability and selectivity in a lab environment. The composite of DAAO-Hb/MnO2 NPs/PTh to construct a bi-enzyme biosensor in this study showed a linear response with DA in the concentration range of 0.04–9.0μM with R-squared value of 0.994 (for S/N=3) and its sensitivity and detection limite were about 12.801μA/μM and 41nM respectively. Also this bi-enzyme biosensors exhibited high selectivity, rapid response (5s) and long-term stability (42days). At the end, the proposed biosensor was applied successfully in human serum as real sample.

Abstract 745: Hybrid bioactive nanoparticles for modulating prostate tumor microenvironment and enhancing radiation therapy

Abstract Introduction Tumor hypoxia is a poor prognostic factor in a number of malignancies such as prostate cancer (PCa). Clinically relevant hypoxic levels are detected in 30-90% PCa with oxygen concentrations below that required for half-maximal radiosensitivity, thus making radiotherapy (RT) ineffective alone [10]. Recently our lab has created pharmaceutically acceptable bioreactive hybrid manganese dioxide nanoparticles (MDNPs) and demonstrated their ability to modulate tumor microenvironment (TME) by reacting with H2O2 and protons and producing O2 in hypoxic tumors, as well as to enhance radiation response of tumor. Methods Lipid encapsulated and polymer stabilizedMDNPs (LMD NPs) were prepared by dispersing MnO2 precursor particles in melted lipid and polymer and then characterized for the particle size and zeta potential. In-vitro oxygen generation of LMD NPs was examined by measuring oxygen saturation level (sO2) in the blood using photoacoustic (PA) imaging method with addition of LMD NPs and H2O2. Biodistribution of LMD NPs in PCa tumor-bearing mice was evaluated by using a Xenogen IVIS Spectrum Imaging System following IV injection of ICG labeled NPs through the tail vein. Mice were monitored non-invasively for up to 24 hours. To investigate the effect of combination of MDNPs and radiation therapy on tumor growth delay and survival, PCa tumor-bearing mice were treated intravenously with LMD NPs with saline as a control. Four hour post injection, 10 Gy radiation dose was given at the site of the tumor. Mice were monitored every 2 days by measuring tumor size using a caliper. Mice were sacrificed when the tumor size reached 500 mm3. Results PA imaging demonstrated a controlled and prolonged generation of O2 in the blood with maximum oxygen saturation (90-95%) being reached within 60 min after incubation with LMD NPs and H2O2. The biodistribution and ex-vivo images of the resected organs showed that LMD NPs accumulated in the prostate tumor sites within 1 h post i.v. injection and remained in the tumor for at least 24 h. The ex vivo optical data of excised tissue showed a significant uptake of LMD nanoparticles by prostate tumor 24 hpost particle administration. The combination of LMD NPs treatment with single dose 10 Gy RT inhibited tumor growth by 24% at 5 days post treatment, whereas the tumor size increased about 47% in mice treated with RT alone. LMD NPs plus RT also improved survival rate of the cancerous mice for up to 53 days, which was about 3.3-fold enhancement in the mean survival rate compared to saline plus RT treatment (30 days). Conclusion The new bioreactive MnO2 NPs exhibited desirable oxygen- generating profile and high tumor accumulation and retention after systemic administration. This work has demonstrated, in a preclinical prostate tumor model, that the combination of LMD NPs with radiation therapy is a promising treatment approach for solid tumor.. Citation Format: Mohammad Ali Amini, Azhar Z. Abbasi, Claudia R. Gordijo1, Ping Cai, Andrew M. Rauth, Robert G. Bristow, Xiao Yu Wu. Hybrid bioactive nanoparticles for modulating prostate tumor microenvironment and enhancing radiation therapy. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 745.

H2O/air plasma-functionalized carbon nanotubes decorated with MnO2 for glucose sensing

MnO2 NPs were decorated on the DBD plasma-functionalized MWCNTs in H2O vapor-saturated air for glucose detection.

Bioconjugated Manganese Dioxide Nanoparticles Enhance Chemotherapy Response by Priming Tumor-Associated Macrophages toward M1-like Phenotype and Attenuating Tumor Hypoxia.

Hypoxia promotes not only the invasiveness of tumor cells, but also chemoresistance in cancer. Tumor associated macrophages (TAMs) residing at the site of hypoxic region of tumors have been known to cooperate with tumor cells, and promote proliferation and chemoresistance. Therefore, there is an urgent need for new strategies to alleviate tumor hypoxia and enhance chemotherapy response in solid tumors. Herein, we have taken advantage of high accumulation of TAMs in hypoxic regions of tumor and high reactivity of manganese dioxide nanoparticles (MnO2 NPs) toward hydrogen peroxide (H2O2) for the simultaneous production of O2 and regulation of pH to effectively alleviate tumor hypoxia by targeted delivery of MnO2 NPs to the hypoxic area. Furthermore, we also utilized the ability of hyaluronic acid (HA) modification in reprogramming anti-inflammatory, pro-tumoral M2 TAMs to pro-inflammatory, antitumor M1 macrophages to further enhance the ability of MnO2 NPs to lessen tumor hypoxia and modulate chemoresistance. The HA-coated, mannan-conjugated MnO2 particle (Man-HA-MnO2) treatment significantly increased tumor oxygenation and down-regulated hypoxia-inducible factor-1 α (HIF-1α) and vascular endothelial growth factor (VEGF) in the tumor. Combination treatment of the tumors with Man-HA-MnO2 NPs and doxorubicin significantly increased apparent diffusion coefficient (ADC) values of breast tumor, inhibited tumor growth and tumor cell proliferation as compared with chemotherapy alone. In addition, the reaction of Man-HA-MnO2 NPs toward endogenous H2O2 highly enhanced T1- and T2-MRI performance for tumor imaging and detection.

Manganese Dioxide/Reduced Graphene Oxide with Poly(3,4-ethylenedioxythiophene) for Improved Electrocatalytic Oxygen Reduction Reaction.

Poly(3,4-ethylenedioxythiophene)-(PEDOT)-functionalized reduced graphene oxide (rGO) with MnO2 nanoparticles (MnO2/PEDOT/rGO) was prepared using electrochemical methods. The MnO2/ PEDOT/rGO was obtained through the electrochemical reduction of PEDOT/GO and under electrochemical treatment in KMnO4. The PEDOT/rGO and MnO2/PEDOT/rGO were characterized by several instrumental and electrochemical methods. The electrocatalytic 02 reduction for both electrodes was investigated via cyclic and hydrodynamic voltammetry in 0.1 M KOH aqueous solutions. The kinetic analysis in comparison to PEDOT/rGO a significant enhancement was found for the MnO2/PEDOT/rGO. The proposed main path in the oxygen reduction reaction (ORR) mechanism on the MnO2/PEDOT/rGO was the direct four-electron transfer process with faster transfer kinetic rate. The better ORR kinetics were obtained due to the excellent composite formation and well attachment of MnO2 NPs within oxide form. The PEDOT/rGO was less stable for long term use than MnO2/PEDOT/rGO.