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1.
Chemosphere ; 239: 124745, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31521939

RESUMO

A novel three dimensional MnO2 modified biochar-based porous hydrogel (MBCG) was fabricated to overcome the low sorption capacity and difficulty in solid-liquid separation of biochar (BC) for Cd(II) and Pb(II) removal. BC was initially modified by a rapid redox reaction between KMnO4 and Mn(II) acetate, and then incorporated into a polyacrylamide gel network via a rapid and facile free-radical polymerization. A foaming method was deliberately introduced during the fabrication to establish interpenetrated porous structure inside the network. Various characterizations were employed to examine the morphology, porous structures, chemical compositions, and mechanical properties of the samples. Adsorption performance of MBCG on Cd(II) and Pb(II) (isotherms and kinetics) as well as its desorption and reusability were also investigated. The results indicated that MnO2 modified biochars (MBC) were successfully introduced and homogeneously distributed in the porous bulk hydrogel, endowing MBCG with more uniform pore structure, excellent thermostability, remarkable mechanic strength, and superior adsorption performance. The maximum Langmuir adsorption capacity on Cd(II) and Pb(II) is 84.76 and 70.90 mg g-1, respectively, which is comparable or even larger than that of MBC. More importantly, MBCG can be rapidly separated and easily regenerated with an excellent reusability, which could retain 92.1% and 80.5% of the initial adsorption capacities of Cd(II) and Pb(II) after five cycles. These new insights make MBCG an ideal candidate in practical applications in water treatment and soil remediation contaminated with various heavy metals.


Assuntos
Cádmio/isolamento & purificação , Carvão Vegetal/química , Hidrogéis/química , Chumbo/isolamento & purificação , Compostos de Manganês/química , Óxidos/química , Resinas Acrílicas/química , Adsorção , Cádmio/química , Poluentes Ambientais/química , Poluentes Ambientais/isolamento & purificação , Chumbo/química , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Polimerização , Porosidade , Impressão Tridimensional , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria
2.
Chem Commun (Camb) ; 56(6): 976-979, 2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-31859315

RESUMO

By using multivalent manganese oxides microflowers (MnOx MFs) as prominent a coreaction accelerator in luminol/dissolved oxygen system, and by combining these with DNA nanostructures for efficient immobilization of the electrochemiluminescence (ECL) quencher doxorubicin-ferrocenecarboxylic acid (Dox-FcCOOH), an ultrasensitive biosensing platform was constructed to conduct a microRNA assay in tumour cells.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Medições Luminescentes , Compostos de Manganês/química , MicroRNAs/análise , Óxidos/química , DNA/química , Doxorrubicina/química , Compostos Ferrosos/química , Metalocenos/química , Nanoestruturas/química
3.
Talanta ; 206: 120199, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514856

RESUMO

A new class of intracellular signal amplification approach, integrating biodegradable manganese dioxide (MnO2) nanosheet with target-triggered DNAzyme recycling amplification in one nanosystem, was developed for highly specific and sensitive monitoring of microRNAs (miRNAs) in living cells. Briefly, the MnO2 nanosheets were employed as carrier and quencher for the hairpin-locked-DNAzyme strands (H1). Upon entering cells, the surface-adsorbed strands (H1) can be released due to the degradation of the MnO2 nanosheets by cellular glutathione. Subsequently, the hybridization reaction between target miRNAs and H1 probe induced the conformation alteration of the hairpin probes H1, formed an "active" DNAzyme. With the assistor of Mg2+, the DNAzyme was activated and induced the release of the fluorophores labeled DNA fragment, which achieved the restoration of fluorescence signal. Meanwhile, the target molecules was released and hybridized with the other H1 strand to initiate another cycle of activation, cleavage, and turnovers, which producing enhanced fluorescence signal for sensitive analysis of intracellular miRNAs. Furthermore, fluorescence imaging experiments demonstrated that the MnO2-DNAzyme nanosystem could visually detect microRNA-21 in cancer cells. The proposed strategy provides a good platform for highly sensitive detection and imaging analysis of various intracellular miRNAs in situ.


Assuntos
DNA Catalítico/química , Compostos de Manganês/química , MicroRNAs/análise , Nanoestruturas/química , Óxidos/química , Sequência de Bases , Linhagem Celular Tumoral , DNA Catalítico/genética , Corantes Fluorescentes/química , Humanos , Sequências Repetidas Invertidas , MicroRNAs/genética , Microscopia Confocal/métodos , Microscopia de Fluorescência/métodos , Conformação de Ácido Nucleico , Hibridização de Ácido Nucleico
4.
Chemosphere ; 239: 124763, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31526989

RESUMO

Nonredox metal ions have been widely recognized to be important in a wide range of biological and chemical oxidations as Lewis acids (LA). However, the role of LA in peroxymonosulfate (PMS) activation for wastewater treatment has not been considered until now. This study shows that oxidizing power of PMS can be promoted after binding nonredox metal ions such as Ca2+ as LA, leading to the easier reduction of the oxidant to radicals and substantial enhancement of dye degradation by employing manganese oxides OMS-2 as model catalysts. Increased with Lewis acidity of the metal ion, the rate of PMS decomposition enhanced linearly, while the dye degradation rate first increased and then declined due to the formation of a larger amount of dioxygen. The interactions between Ca2+ and PMS were further investigated by Raman, cyclic voltammetry and XPS; and the detailed mechanism of PMS activation was proposed. The performance of Ca2++OMS-2/PMS system under different conditions was also studied. The findings indicate the importance of LA in PMS activation reaction and their role must be considered in other transition metal oxides/PMS systems. It will be also helpful to design new and highly active catalysts for the reactions.


Assuntos
Ácidos de Lewis/química , Compostos de Manganês/química , Óxidos/química , Peróxidos/química , Poluentes Químicos da Água/química , Cálcio/química , Catálise , Corantes/química , Oxidantes/química , Oxirredução , Soluções , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química
5.
Analyst ; 144(24): 7398-7405, 2019 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-31670357

RESUMO

α-Glucosidase and its inhibitors play a key role in diagnosis and treatment of diabetes. In the present work, we established a facile, sensitive and selective fluorescence method based on silicon quantum dots (SiQDs) and MnO2 nanosheets for the determination of α-glucosidase and one of its inhibitors acarbose. The fluorescence of SiQDs was greatly quenched by MnO2 nanosheets due to the inner filter effect. α-Glucosidase could easily catalyze the hydrolysis of l-ascorbic acid-2-O-α-d-glucopyranosyl (AAG) to produce ascorbic acid (AA), which could reduce MnO2 nanosheets to Mn2+, resulting in dramatic recovery of the fluorescence of SiQDs. The proposed sensing platform could provide a good linear relationship between the fluorescence intensity of SiQDs and the concentration of α-glucosidase in the range of 0.02-2.5 U mL-1 with a detection limit of 0.007 U mL-1. In addition, the sensing platform could be used for α-glucosidase inhibition. Acarbose was one of the most common and typical inhibitors, and this sensing platform can be utilized to detect acarbose in the range of 1-1000 µM. The developed fluorescence method was successfully validated for the determination of α-glucosidase in human serum samples.


Assuntos
Corantes Fluorescentes/química , Inibidores de Glicosídeo Hidrolases/análise , Nanocompostos/química , Pontos Quânticos/química , alfa-Glucosidases/sangue , Humanos , Compostos de Manganês/química , Óxidos/química , Silício/química , Espectrometria de Fluorescência
6.
Int J Nanomedicine ; 14: 8499-8507, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31695377

RESUMO

Background: Beyond magnetic resonance imaging (MRI), which has been widely used clinically, molecular MRI (mMRI) can further provide qualitative and quantitative information at the cellular and molecular levels. However, the diagnostic accuracy may not be satisfactory via single-contrast mMRI due to some interferences in vivo. T1/T2 dual-contrast MRI using the same contrast agent (CA) could significantly improve the detection accuracy. Therefore, in this study, we fabricated poly(ethylene glycol) (PEG)-coated, manganese-doped iron oxide nanocomposites (Mn-IONPs@PEG) as T1/T2 dual-contrast CA, and evaluated its feasibility of T1/T2 dual-contrast MRI in vitro and in vivo. Methods: Mn-IONPs were prepared by the thermal decomposition of iron-eruciate and manganese-oleate complexes and were coated with 1,2-Distearoyl-sn-glycero-3-phosphoethanolamine-N-(methoxy[polyethylene glycol]-2000) (DSPE-PEG 2000). The physicochemical properties and cytotoxicity of the Mn-IONPs were fully characterized, followed by MRI in vitro and in vivo. Results: Ultrasmall 3 nm-sized nanoparticles were successfully prepared and were identified using transmission electron microscopy (TEM), high-resolution TEM, and X-ray diffraction. After coating with DSPE-PEG, the Mn-IONPs@PEG displayed excellent hydrophilicity and good biocompatibility. Due to the manganese-doping and PEG coating, the Mn-IONPs@PEG showed good relaxivity in vitro. Especially, the Mn-IONPs@PEG coated with DSPE-PEG following a mass ratio to Mn-IONPs of 1:20 showed harmonious longitudinal relaxivity (r 1 = 7.1 mM-1s-1) and transversal relaxivity (r 2 = 120.9 mM-1s-1), making it a better candidate for T1/T2 dual-contrast mMRI. After administrated via a caudal vein, the Mn-IONPs@PEG can induce significant enhancement in both T1-weighted and T2-weighted MR images and the time at 10 mins after injection was regarded as a suitable time for imaging because both the T1 and T2 enhancement were optimum at that time. Conclusion: The obtained Mn-IONPs@PEG exhibited good r 1 and r 2 and was a reasonable candidate for T1/T2 dual-contrast mMRI.


Assuntos
Compostos Férricos/química , Imagem por Ressonância Magnética , Compostos de Manganês/química , Nanopartículas/química , Óxidos/química , Tamanho da Partícula , Polietilenoglicóis/química , Animais , Sobrevivência Celular , Meios de Contraste/química , Células Hep G2 , Humanos , Fígado/patologia , Camundongos Endogâmicos C57BL , Nanopartículas/ultraestrutura
7.
Int J Nanomedicine ; 14: 8321-8344, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31695370

RESUMO

Contrast agents (CAs) play a crucial role in high-quality magnetic resonance imaging (MRI) applications. At present, as a result of the Gd-based CAs which are associated with renal fibrosis as well as the inherent dark imaging characteristics of superparamagnetic iron oxide nanoparticles, Mn-based CAs which have a good biocompatibility and bright images are considered ideal for MRI. In addition, manganese oxide nanoparticles (MONs, such as MnO, MnO2, Mn3O4, and MnOx) have attracted attention as T1-weighted magnetic resonance CAs due to the short circulation time of Mn(II) ion chelate and the size-controlled circulation time of colloidal nanoparticles. In this review, recent advances in the use of MONs as MRI contrast agents for tumor detection and diagnosis are reported, as are the advances in in vivo toxicity, distribution and tumor microenvironment-responsive enhanced tumor chemotherapy and radiotherapy as well as photothermal and photodynamic therapies.


Assuntos
Meios de Contraste/química , Imagem por Ressonância Magnética/métodos , Compostos de Manganês/química , Imagem Multimodal/métodos , Nanopartículas/química , Neoplasias/diagnóstico por imagem , Neoplasias/terapia , Óxidos/química , Humanos , Neoplasias/diagnóstico
8.
Bull Environ Contam Toxicol ; 103(6): 763-765, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31628499

RESUMO

Quantifying the coupled kinetic reactions of metals/metalloids on iron and manganese oxides is essential for predicting the fate of contaminants in the environment. In this perspective, a few key issues related to developing the quantitative models for the coupled kinetic reactions of metal and metalloids are discussed, including adsorption/desorption processes, redox reactions, and mineral dissolution/transformation. Future research areas are also briefly discussed.


Assuntos
Poluentes Ambientais/química , Ferro/química , Compostos de Manganês/química , Metaloides/química , Metais/química , Óxidos/química , Adsorção , Cinética , Minerais/química , Modelos Químicos , Oxirredução
9.
Chem Commun (Camb) ; 55(89): 13366-13369, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31631205

RESUMO

A target-triggered, self-powered strategy for in situ monitoring of intracellular microRNAs was fabricated via a versatile DNAzyme-MnO2 nanosystem, which integrates delivery, quenching, target recognition, self-supply of cofactors and signal amplification all in one.


Assuntos
Sobrevivência Celular , DNA Catalítico/química , Compostos de Manganês/química , MicroRNAs/análise , Nanopartículas/química , Imagem Óptica , Óxidos/química , Linhagem Celular Tumoral , DNA Catalítico/metabolismo , Células HeLa , Humanos , Células MCF-7 , Compostos de Manganês/metabolismo , Nanopartículas/metabolismo , Óxidos/metabolismo
10.
Environ Pollut ; 255(Pt 1): 113192, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31541813

RESUMO

Adsorption and fractionation of Pt, Pd and Rh (defined here as platinum group elements, PGEs) onto the representative inorganic microparticles, including Fe2O3, MnO2, CaCO3, SiO2, Al2O3 and kaolinite in seawater were investigated. The effects of macromolecular organic compounds (MOCs) as the representatives of organic matter, including humic acids (HA), bovine serum albumin (BSA) and carrageenan, on the adsorption were also studied considering that organic matter is ubiquitous in seawater and indispensable to marine biogeochemical cycles. In the absence of MOCs, the representative mineral particles Fe2O3 and MnO2 had the strongest interaction with PGEs. The adsorption of PGEs onto the representative biogenic particles SiO2 and CaCO3 and lithogenic particles Al2O3 and kaolinite was similar or weaker than onto the mineral particles. MOCs inhibited the interaction between PGEs and the particles except for Pt and Pd onto the biogenic particles in artificial seawater. This impediment may be closely related to the interaction between particles, MOCs and elements. The partition coefficient (log Kd) of Pt was similar (∼4.0) in the presence of MOCs, indicating that the complexation between Pt and MOCs was less important than hydrolysis or adsorption onto the acid oxide particle surface. Rh tended to fractionate onto the mineral and lithogenic particles in the presence of HA and carrageenan, while Pd was more likely to fractionate onto the biogenic particles. However, BSA enhanced the fractionation tendency of Pd onto the mineral particles. The results indicate that the adsorption behavior of Pd onto inorganic particles was significantly affected by the composition or the type of MOCs. Hence, the interaction between PGEs and inorganic particles may be greatly affected by the macromolecular organic matter in the ocean.


Assuntos
Compostos Inorgânicos/química , Nanopartículas Metálicas/análise , Paládio/análise , Platina/análise , Ródio/análise , Água do Mar/química , Adsorção , Compostos Férricos/química , Substâncias Húmicas/análise , Caulim/química , Compostos de Manganês/química , Minerais/química , Compostos Orgânicos/química , Óxidos/química , Dióxido de Silício/química
11.
Molecules ; 24(18)2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31505808

RESUMO

A rapid and accurate determination method for total phenolic content is of great importance for controlling the quality of wine samples. A promising potentiometric detection approach, based on permanganate ion fluxes across ion-selective electrode membranes, is fabricated for measuring the total phenolic content of wine. The results show that the presence of phenols, such as gallic acid, leads to a potential increase for the potentiometric sensor. Additionally, the present sensor exhibits a linear potential response with the concentration range from 0.05 to 3.0 g/L with a detection limit of 6.6 mg/L calculated using gallic acid. These sensors also exhibit a fast response time, an acceptable reproducibility and long-term stability. These results indicate that the proposed potentiometric sensor can be a promising and reliable tool for the rapid determination of total phenolic content in wine samples.


Assuntos
Compostos de Manganês/química , Óxidos/química , Fenóis/isolamento & purificação , Potenciometria , Vinho/análise , Humanos , Íons/química , Fenóis/química
13.
Mater Sci Eng C Mater Biol Appl ; 104: 109979, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31500001

RESUMO

The efficacy of photodynamic therapy (PDT) is reduced in the context of hypoxic environments. This is problematic, considering that hypoxia is exhibited in the vast majority of malignant tumors. Thus, increasing the concentration of oxygen in malignant tumors improves PDT treatment outcomes. Studies show that MnO2 nanoparticles can produce oxygen when it reacts with endogenous H2O2. Herein, we encapsulated Protoporphyrin IX (PPIX) in the liposome bilayer (PPIX-Lipo), which was then coated with MnO2 nanoparticles to construct PPIX-Lipo-MnO2 (PPIX-Lipo-M) in order to enhance PDT efficacy under tumor hypoxia. The PDT results show that PPIX-Lipo-M was more cytotoxic to breast cancer cells than PPIX-Lipo while under hypoxic conditions, indicating that the production of oxygen gas in hypoxic conditions improved treatment outcomes. Upon encapsulating PPIX into the liposome, the aqueous solubility of PPIX significantly improved. Consequently, the cellular uptake of both PPIX-Lipo and PPIX-Lipo-M also increased significantly compared to that of bare PPIX. Overall, PPIX-Lipo-M has the capacity to act as a therapeutic agent that relieves hypoxia and hence improve PDT efficacy.


Assuntos
Neoplasias da Mama/tratamento farmacológico , Lipossomos/química , Compostos de Manganês/química , Óxidos/química , Protoporfirinas/química , Protoporfirinas/farmacologia , Hipóxia Tumoral/efeitos dos fármacos , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Feminino , Humanos , Peróxido de Hidrogênio/farmacologia , Células MCF-7 , Nanopartículas/química , Oxigênio/química , Fotoquimioterapia/métodos
14.
Ecotoxicol Environ Saf ; 184: 109671, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31539809

RESUMO

Abiotic stress has become one of the most challenging problems for agriculture as the world population keeps increasing dramatically. Crop stress management using manganese (Mn) compounds has been recently employed to reduce the negative effects caused by drought, harsh temperature, and salinity. In response to abiotic stress, an adequate supply of Mn has shown to remediate plant manganese deficiency, induce Mn superoxide dismutase at the transcriptional level to face reactive oxygen species production, and stimulate manganese-dependent proteins to maintain cell integrity. Lately, nanoparticles (NPs) have been explored in agriculture applications. Recent studies have implied that Mn NPs may help plants to overcome abiotic stresses at higher efficiency and lower toxicity, compared to their bulk or ionic counterparts. Although studies have shown that Mn compounds promote crop growth and alleviate abiotic stress, many questions related to Mn-plant networking, their mode of signaling, and the Mn-dependent regulation processes need to be answered.


Assuntos
Produtos Agrícolas/efeitos dos fármacos , Compostos de Manganês/farmacologia , Manganês/farmacologia , Nanopartículas/química , Estresse Fisiológico/efeitos dos fármacos , Produtos Agrícolas/metabolismo , Secas , Manganês/química , Compostos de Manganês/química , Espécies Reativas de Oxigênio/metabolismo , Salinidade , Superóxido Dismutase/metabolismo
15.
Biosens Bioelectron ; 143: 111634, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31473379

RESUMO

In this work, Ni(OH)2 nanocages@MnO2 nanosheets core-shell architecture (Ni(OH)2 NCs@MnO2 NSs CSA) was successfully prepared through coordinated etching and precipitation (CEP) route followed by hydrothermal reaction, and then tested as sensitive electrode material for detection of dopamine (DA). The three dimensional (3D) hollow Ni(OH)2 core effectively prevented the aggregation of MnO2 NSs, leading to high utilization rate of MnO2 NSs. Meanwhile, the two dimensional (2D) MnO2 shell endowed Ni(OH)2 NCs with larger specific area and abundant diffusion channels, facilitating mass transport. Ni(OH)2 NCs@MnO2 NSs CSA modified glassy carbon electrode (GCE) exhibited two satisfying sensitivities of 467.1 and 1249.9 µA mM-1 cm-2 within the two linear ranges of 0.02-16.30 µM and 18.30-118.58 µM, respectively. Furthermore, Ni(OH)2 NCs@MnO2 NSs CSA/GCE presented low detection limit of 1.75 nM and short response time of 1.14 s. Overall, Ni(OH)2 NCs@MnO2 NSs/GCE looks promising for analytical sensing of DA thanks to its prominent electrocatalytic dynamic issued from the 3D hollow structure@2D nanosheets core-shell architecture.


Assuntos
Técnicas Biossensoriais , Dopamina/isolamento & purificação , Técnicas Eletroquímicas , Nanoestruturas/química , Dopamina/química , Hidróxidos/química , Compostos de Manganês/química , Níquel/química
16.
J Photochem Photobiol B ; 198: 111579, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31401316

RESUMO

The sol-gel/ultrasonically rout produced the novel MnS2-SiO2 nano-hetero-photocatalysts with the various ratio of MnS2. Prepared nano-catalyst were investigated in the photo-degradation of methylene blue under UV light illumination. Structural and optical attributes of as-prepared nano-catalysts were evaluated by X-ray diffraction and photoelectron spectroscopy. The morphological were studied by scanning electron microscopy-EDS, and dynamic light scattering. The diffuse reflectance spectroscopy was applied to examine the band gap energy. The Eg values of SiO2, MnS2-SiO2-0, MnS2-SiO2-1, and MnS2-SiO2-2 nanocomposites are 6.51, 3.85, 3.17, and 2.67 eV, respectively. The particle size of the SiO2 and MnS2-SiO2-1 nanocomposites were 100.0, and 65.0 nm, respectively. The crystallite size values of MnS2-SiO2-1 were 52.21 nm, and 2.9 eV, respectively. MnS2-SiO2 nano-photocatalyst was recognized as the optimum sample by degrading 96.1% of methylene blue from water. Moreover, the influence of pH of the solution, and contact time as decisive factors on the photo-degradation activity were investigated in this project. The optimum data for pH and time were found 9 and 60 min, respectively. The photo-degradation capacity of MnS2-SiO2-2 is improved (96.1%) due to the low band gap was found from UV-vis DRS. The antimicrobial data of MnS2-SiO2 were studied and demonstrated that the MnS2-SiO2 has fungicidal and bactericidal attributes.


Assuntos
Anti-Infecciosos/química , Antioxidantes/química , Compostos de Manganês/química , Nanocompostos/química , Óxidos/química , Dióxido de Silício/química , Raios Ultravioleta , Anti-Infecciosos/síntese química , Anti-Infecciosos/farmacologia , Antioxidantes/síntese química , Catálise , Escherichia coli/efeitos dos fármacos , Fungos/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Azul de Metileno/química , Tamanho da Partícula , Streptococcus pyogenes/efeitos dos fármacos
17.
J Appl Oral Sci ; 27: e20180453, 2019 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-31411261

RESUMO

OBJECTIVE: This study was designed for the chemical activation of a 35% hydrogen peroxide (H2O2) bleaching gel to increase its whitening effectiveness and reduce its toxicity. METHODOLOGY: First, the bleaching gel - associated or not with ferrous sulfate (FS), manganese chloride (MC), peroxidase (PR), or catalase (CT) - was applied (3x 15 min) to enamel/dentin discs adapted to artificial pulp chambers. Then, odontoblast-like MDPC-23 cells were exposed for 1 h to the extracts (culture medium + components released from the product), for the assessment of viability (MTT assay) and oxidative stress (H2DCFDA). Residual H2O2 and bleaching effectiveness (DE) were also evaluated. Data were analyzed with one-way ANOVA complemented with Tukey's test (n=8. p<0.05). RESULTS: All chemically activated groups minimized MDPC-23 oxidative stress generation; however, significantly higher cell viability was detected for MC, PR, and CT than for plain 35% H2O2 gel. Nevertheless, FS, MC, PR, and CT reduced the amount of residual H2O2 and increased bleaching effectiveness. CONCLUSION: Chemical activation of 35% H2O2 gel with MC, PR, and CT minimized residual H2O2 and pulp cell toxicity; but PR duplicated the whitening potential of the bleaching gel after a single 45-minute session.


Assuntos
Peróxido de Hidrogênio/química , Peróxido de Hidrogênio/toxicidade , Clareadores Dentários/química , Clareadores Dentários/toxicidade , Clareamento Dental/métodos , Análise de Variância , Catalase/química , Sobrevivência Celular , Células Cultivadas , Cloretos/química , Cor , Polpa Dentária/química , Polpa Dentária/diagnóstico por imagem , Dentina/química , Dentina/efeitos dos fármacos , Compostos Ferrosos/química , Compostos de Manganês/química , Odontoblastos/efeitos dos fármacos , Peroxidase/química , Valores de Referência , Reprodutibilidade dos Testes , Estatísticas não Paramétricas , Fatores de Tempo
18.
Nanoscale ; 11(33): 15508-15518, 2019 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-31393496

RESUMO

Although the collaborative therapy of chemotherapy (CT) and photodynamic therapy (PDT) is much more efficient for tumor treatment than monotherapies, premature leakage of drugs from nanocarriers and hypoxia in the tumor microenvironment (TME) result in systemic toxicity and suboptimal therapy efficiency. To overcome these limitations, we developed an intelligent nanoflower composite (termed FHCPC@MnO2) by coating functionalized polyphosphazene on superparamagnetic Fe3O4 nanoclusters and then growing MnO2 nanosheets as an outer shell. The FHCPC@MnO2 nanoflowers with multistage H2O2/pH/GSH-responsive properties could fully exploit TME characteristics, including supernormal glutathione (GSH) levels, low pH and high H2O2, to realize the specific release of drugs in tumors and maximum synergetic therapeutic effects. The MnO2 nanosheets can elevate O2 concentration by catalytic decomposition of H2O2 and can be simultaneously reduced to Mn2+ by overexpressed GSH in the acidic TME. Meanwhile, the inner polyphosphazene containing (bis-(4-hydroxyphenyl)-disulfide) is GSH- and pH-sensitively biodegradable to release the anticancer drug curcumin (CUR) and photosensitizer chlorin e6 (Ce6) in the TME. Therefore, the "triple-responsive" and synergetic strategy simultaneously endows the nanoflowers with specific drug release, relieving hypoxia and the antioxidant capability of the tumor and achieving significant optimization of CT and PDT. In addition, the resulting Mn2+ ions and Fe3O4 core enable in vivo T1/T2 magnetic resonance imaging (MRI), while the released Ce6 can simultaneously provide a fluorescence imaging (FL) function. Unsurprisingly, the intelligent nanoflowers exhibited remarkable multimodal theranostic performance both in vitro and in vivo, suggesting their great potential for precision medicine.


Assuntos
Nanoestruturas/química , Nanomedicina Teranóstica , Animais , Antineoplásicos/química , Antineoplásicos/metabolismo , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Sobrevivência Celular/efeitos dos fármacos , Óxido Ferroso-Férrico/química , Glutationa/química , Células HeLa , Humanos , Peróxido de Hidrogênio/química , Concentração de Íons de Hidrogênio , Imagem por Ressonância Magnética , Nanopartículas de Magnetita/química , Compostos de Manganês/química , Camundongos , Camundongos Nus , Neoplasias/tratamento farmacológico , Óxidos/química , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/metabolismo , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/uso terapêutico , Oxigênio Singlete/química , Oxigênio Singlete/metabolismo , Microambiente Tumoral
19.
Molecules ; 24(16)2019 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-31426454

RESUMO

The electrical characterization of catalysts composed of layered manganese oxide in the form of birnessite supported on γ-Al2O3, which have been successfully used in the combustion of soot, is presented. The results indicate that the electrical conduction and ion conduction processes are influenced by the amount of the active phase. There was also evidence of Grotthuss-type proton conductivity favored by the presence of surface water on the exposed alumina surface. The above is supported by the porous nature of the catalyst in which the surface area varied between 125.2 ± 1.2 and 159.0 ± 1.1 m2/g, evidencing changes in the alumina surface. The conductivity, determined from measurements of impedance spectroscopy, at low frequency showed changes associated with the amount of the active phase. The values ranged from 2.61 × 10-8 ± 2.1 × 10-9 Ω-1·cm-1 (pure alumina) to 7.33 × 10-8 ± 5.9 × 10-9 Ω-1·cm-1, 7.21 × 10-8 ± 5.8 × 10-9 Ω-1·cm-1 and 4.51 × 10-7 ± 3.6 × 10-8 Ω-1·cm-1 at room temperature for catalysts with nominal active phase contents of 5.0, 10.0 and 20.0%, respectively. Such results indicate that it is possible to modulate the electrical properties with variations in the synthesis parameters.


Assuntos
Óxido de Alumínio/química , Compostos de Manganês/química , Óxidos/química , Catálise , Condutividade Elétrica , Estrutura Molecular , Porosidade , Prótons , Água/química
20.
Bioelectrochemistry ; 130: 107347, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31437809

RESUMO

A multifunctional nanocomposite theranostic system is constructed of manganese oxide (Mn3O4) nanoparticles (NPs), as a tumor diagnostic agent, in conjunction with polyacrylic acid (PAA), as a pH-sensitive drug delivery agent, and methotrexate (MTX), as a model of targeting agent and anticancer drug. Physicochemical characteristics of the Mn3O4@PAA/MTX system is studied in detail by several techniques, including X-ray and Auger photoelectron spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and electrochemical methods. The system performance is studied based on (i) in-vitro MRI measurements to support efficiency of the Mn3O4@PAA NPs as a diagnostic agent, (ii) drug release performance of the Mn3O4@PAA/MTX NPs at pHs of 5.4 and 7.4 through in-vitro method to evaluate application of the NPs as pH-sensitive nanocarriers for MTX, and (iii) impedance spectroscopy measurements to show Mn3O4@PAA/MTX NPs affinity for capturing of cancer cells. The results show that (i) Mn3O4@PAA NPs can be used as a contrast agent in MRI measurements (r1 ≅ 6.5 mM-1 s-1), (ii) the MTX, loaded on Mn3O4@PAA NPs, is released faster and more efficient at pH 5.4 than 7.4, and (iii) the GC-Mn3O4@PAA/MTX electrode system captures the 4T1 cells 3.32 times larger than L929 cells.


Assuntos
Resinas Acrílicas/química , Antineoplásicos/administração & dosagem , Preparações de Ação Retardada/química , Compostos de Manganês/química , Metotrexato/administração & dosagem , Nanopartículas/química , Óxidos/química , Animais , Antineoplásicos/farmacocinética , Antineoplásicos/farmacologia , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/tratamento farmacológico , Linhagem Celular Tumoral , Meios de Contraste/química , Liberação Controlada de Fármacos , Feminino , Concentração de Íons de Hidrogênio , Imagem por Ressonância Magnética , Metotrexato/farmacocinética , Metotrexato/farmacologia , Camundongos , Nanomedicina Teranóstica
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