Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 5.438
Filtrar
1.
Biomed Eng Online ; 23(1): 53, 2024 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-38858706

RESUMO

BACKGROUND: Metastasis is one of the main factors leading to the high mortality rate of gastric cancer. The current monitoring methods are not able to accurately monitor gastric cancer metastasis. METHODS: In this paper, we constructed a new type of hollow Mn 3 O 4 nanocomposites, Mn 3 O 4 @HMSN-Cy7.5-FA, which had a size distribution of approximately 100 nm and showed good stability in different liquid environments. The in vitro magnetic resonance imaging (MRI) results show that the nanocomposite has good response effects to the acidic microenvironment of tumors. The acidic environment can significantly enhance the contrast of T 1 -weighted MRI. The cellular uptake and endocytosis results show that the nanocomposite has good targeting capabilities and exhibits good biosafety, both in vivo and in vitro. In a gastric cancer nude mouse orthotopic metastatic tumor model, with bioluminescence imaging's tumor location information, we realized in vivo MRI/fluorescence imaging (FLI) guided precise monitoring of the gastric cancer orthotopic and metastatic tumors with this nanocomposite. RESULTS: This report demonstrates that Mn 3 O 4 @HMSN-Cy7.5-FA nanocomposites is a promising nano-diagnostic platform for the precision diagnosis and therapy of gastric cancer metastasis in the future. CONCLUSIONS: In vivo MRI/FLI imaging results show that the nanocomposites can achieve accurate monitoring of gastric cancer tumors in situ and metastases. BLI's tumor location information further supports the good accuracy of MRI/FLI dual-modality imaging. The above results show that the MHCF NPs can serve as a good nano-diagnostic platform for precise in vivo monitoring of tumor metastasis. This nanocomposite provides more possibilities for the diagnosis and therapy of gastric cancer metastases.


Assuntos
Ácido Fólico , Imageamento por Ressonância Magnética , Nanocompostos , Metástase Neoplásica , Neoplasias Gástricas , Neoplasias Gástricas/diagnóstico por imagem , Neoplasias Gástricas/patologia , Animais , Nanocompostos/química , Camundongos , Linhagem Celular Tumoral , Humanos , Ácido Fólico/química , Compostos de Manganês/química , Imagem Óptica , Camundongos Nus , Óxidos
2.
J Environ Sci (China) ; 145: 180-192, 2024 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38844318

RESUMO

A pilot-scale filtration system was adopted to prepare filter media with catalytic activity to remove manganese (Mn2+) and ammonium (NH4+-N). Three different combinations of oxidants (KMnO4 and K2FeO4) and reductants (MnSO4 and FeCl2) were used during the start-up period. Filter R3 started up by KMnO4 and FeCl2 (Mn7+→MnOx) exhibited excellent catalytic property, and the NH4+-N and Mn2+ removal efficiency reached over 80% on the 10th and 35th days, respectively. Filter R1 started up by K2FeO4 and MnSO4 (MnOx←Mn2+) exhibited the worst catalytic property. Filter R2 started up by KMnO4 and MnSO4 (Mn7+→MnOx←Mn2+) were in between. According to Zeta potential results, the Mn-based oxides (MnOx) formed by Mn7+→MnOx performed the highest pHIEP and pHPZC. The higher the pHIEP and pHPZC, the more unfavorable the cation adsorption. However, it was inconsistent with its excellent Mn2+ and NH4+-N removal abilities, implying that catalytic oxidation played a key role. Combined with XRD and XPS analysis, the results showed that the MnOx produced by the reduction of KMnO4 showed early formation of buserite crystals, high degree of amorphous, high content of Mn3+ and lattice oxygen with the higher activity to form defects. The above results showed that MnOx produced by the reduction of KMnO4 was more conducive to the formation of active species for catalytic oxidation of NH4+-N and Mn2+ removal. This study provides new insights on the formation mechanisms of the active MnOx that could catalytic oxidation of NH4+-N and Mn2+.


Assuntos
Compostos de Amônio , Filtração , Manganês , Óxidos , Manganês/química , Óxidos/química , Compostos de Amônio/química , Filtração/métodos , Poluentes Químicos da Água/química , Permanganato de Potássio/química , Compostos de Manganês/química , Oxirredução , Eliminação de Resíduos Líquidos/métodos , Compostos de Potássio/química , Adsorção , Compostos Férricos/química , Compostos de Ferro
3.
J Nanobiotechnology ; 22(1): 310, 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38831378

RESUMO

Radiotherapy (RT), including external beam radiation therapy (EBRT) and radionuclide therapy (RNT), realizes physical killing of local tumors and activates systemic anti-tumor immunity. However, these effects need to be further strengthened and the difference between EBRT and RNT should be discovered. Herein, bacterial outer membrane (OM) was biomineralized with manganese oxide (MnO2) to obtain OM@MnO2-PEG nanoparticles for enhanced radio-immunotherapy via amplifying EBRT/RNT-induced immunogenic cell death (ICD) and cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) activation. OM@MnO2-PEG can react with H2O2 and then gradually produce O2, Mn2+ and OM fragments in the tumor microenvironment. The relieved tumor hypoxia improves the radio-sensitivity of tumor cells, resulting in enhanced ICD and DNA damage. Mn2+ together with the DNA fragments in the cytoplasm activate the cGAS-STING pathway, further exhibiting a positive role in various aspects of innate immunity and adaptive immunity. Besides, OM fragments promote tumor antigen presentation and anti-tumor macrophages polarization. More importantly, our study reveals that OM@MnO2-PEG-mediated RNT triggers much stronger cGAS-STING pathway-involved immunotherapy than that of EBRT, owing to the duration difference of RT. Therefore, this study develops a powerful sensitizer of radio-immunotherapy and uncovers some differences between EBRT and RNT in the activation of cGAS-STING pathway-related anti-tumor immunity.


Assuntos
Membrana Externa Bacteriana , Imunoterapia , Compostos de Manganês , Proteínas de Membrana , Nucleotidiltransferases , Óxidos , Nucleotidiltransferases/metabolismo , Compostos de Manganês/química , Proteínas de Membrana/metabolismo , Camundongos , Imunoterapia/métodos , Óxidos/química , Animais , Membrana Externa Bacteriana/metabolismo , Microambiente Tumoral , Linhagem Celular Tumoral , Transdução de Sinais , Humanos , Radioterapia/métodos , Nanopartículas/química , Biomineralização , Morte Celular Imunogênica/efeitos dos fármacos , Neoplasias/terapia , Peróxido de Hidrogênio/metabolismo , Imunidade Inata
4.
Spectrochim Acta A Mol Biomol Spectrosc ; 319: 124559, 2024 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-38830331

RESUMO

In this work, we present a novel colorimetric sensing platform for the sensitive detection of ethamsylate (ETM) usingultrathin MnO2 nanosheets with enhancedoxidase-mimicking activity. A facile template-free hydrothermal process was applied to synthesize the MnO2 nanosheets under mild conditions. The nanosheets exhibited oxidase-mimicking activity, facilitating the conversion of TMB into the blue-colored oxTMB in the absence of H2O2. However, the presence of ETM inhibited this activity, resulting in the conversion of oxTMB back to colorless TMB and a substantial decrease in the blue color intensity. The colorimetric response exhibited a linear relationship with ETM concentration over the range of 0.5 to 10.0 µg/mL and a detection limit of 0.156 µg/mL. To further elucidate the underlying mechanism, we performed extensive characterization and kinetic experiments. The findings demonstrated that this unique property is attributed to the remarkable capacity of the MnO2 nanosheets to absorb oxygen, producing superoxide radicals (O2-). The oxidase-mimicking activity of the nanosheets was further confirmed by the reaction kinetics, following Michaelis-Menten's behavior. Moreover, the applicability of the sensing platform was assessed by determining ETM concentrations in various real samples (different pharmaceuticals, human plasma, and environmental water). The well-established platform demonstrates the prospective role that nanomaterials-based sensing platforms may play in clinical diagnostics, pharmaceutical analysis, and other relevant fields.


Assuntos
Colorimetria , Limite de Detecção , Compostos de Manganês , Nanoestruturas , Óxidos , Oxirredutases , Colorimetria/métodos , Compostos de Manganês/química , Óxidos/química , Nanoestruturas/química , Oxirredutases/metabolismo , Oxirredutases/química , Cinética , Peróxido de Hidrogênio/análise , Peróxido de Hidrogênio/química , Peróxido de Hidrogênio/metabolismo , Materiais Biomiméticos/química , Benzidinas/química
5.
PLoS One ; 19(6): e0304333, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38875253

RESUMO

Magnetic MnFe2O4 nanoparticles were successfully prepared by the rapid combustion method at 500 °C for 2 h with 30 mL absolute ethanol, and were characterized by SEM, TEM, XRD, VSM, and XPS techniques, their average particle size and the saturation magnetization were about 25.3 nm and 79.53 A·m2/kg, respectively. The magnetic MnFe2O4 nanoparticles were employed in a fixed bed experimental system to investigate the adsorption capacity of Hg0 from air. The MnFe2O4 nanoparticles exhibited the large adsorption performance on Hg0 with the adsorption capacity of 16.27 µg/g at the adsorption temperature of 50 °C with the space velocity of 4.8×104 h-1. The VSM and EDS results illustrated that the prepared MnFe2O4 nanoparticles were stable before and after adsorption and successfully adsorbed Hg0. The TG curves demonstrated that the mercury compound formed after adsorption was HgO, and both physical and chemical adsorption processes were observed. Magnetic MnFe2O4 nanoparticles revealed excellent adsorbance of Hg0 in air, which suggested that MnFe2O4 nanoparticles be promising for the removal of Hg0.


Assuntos
Compostos Férricos , Gases , Compostos de Manganês , Mercúrio , Adsorção , Mercúrio/química , Compostos de Manganês/química , Compostos Férricos/química , Gases/química , Tamanho da Partícula , Temperatura
6.
Yakugaku Zasshi ; 144(6): 651-657, 2024.
Artigo em Japonês | MEDLINE | ID: mdl-38825474

RESUMO

Microbial exudates including siderophore, which changes chemical species of actinides and lanthanides. We have investigated effects of desferrioxamine B (DFOB; one of the siderophores) and siderophore-like organic molecules (SLOM) on the adsorption of lanthanides by microbial cells, aluminium oxide (Al2O3), and manganese (Mn) oxides. When DFOB was present, the distribution coefficients of cerium (Ce) were measured to be lower than those of neighboring elements of lanthanum (La) and praseodymium (Pr) (Negative anomaly of Ce adsorption). Even though initial oxidation state of Ce in the solution was III, that was changed to IV after the addition of DFOB, indicating that Ce(III) was oxidized by forming complex with DFOB. When lanthanides were adsorbed by biogenic Mn(IV) oxides, negative anomaly of Ce adsorption was observed in the sorption in alkaline solution. Ce(III) was oxidized to forme the complexes of Ce(IV) with SLOM in the solution. These results show that siderophore possesses high performance of oxidation of Ce(III) to Ce(IV) during association, affectiong the adsorption behavior of Ce. After Fukushima accident, radioactive Cs accumulation by Eleutherococcus sciadophylloides (Koshiabura) caused by the dissolution of Fe from soil around the roots, that was dominated by siderophore releasing microorganisms (SB). These SBs may enhance dissolution of iron (Fe) and uranium (U) phases in the nuclear fuel debris formed in the nuclear reactors in Fukushima Daiichi nuclear power plant. Thus, in the interaction between microorganisms and radionuclides, SLOMs discharged by microorganisms are deeply involved in the chemical state change of radionuclides.


Assuntos
Oxirredução , Sideróforos , Adsorção , Desferroxamina/metabolismo , Óxido de Alumínio/química , Elementos da Série dos Lantanídeos/química , Compostos de Manganês/química , Óxidos , Cério , Radioisótopos
7.
Int J Nanomedicine ; 19: 5837-5858, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38887692

RESUMO

Purpose: Phototherapy, known for its high selectivity, few side effects, strong controllability, and synergistic enhancement of combined treatments, is widely used in treating diseases like cervical cancer. Methods: In this study, hollow mesoporous manganese dioxide was used as a carrier to construct positively charged, poly(allylamine hydrochloride)-modified nanoparticles (NPs). The NP was efficiently loaded with the photosensitizer indocyanine green (ICG) via the addition of hydrogen phosphate ions to produce a counterion aggregation effect. HeLa cell membrane encapsulation was performed to achieve the final M-HMnO2@ICG NP. In this structure, the HMnO2 carrier responsively degrades to release ICG in the tumor microenvironment, self-generates O2 for sensitization to ICG-mediated photodynamic therapy (PDT), and consumes GSH to expand the oxidative stress therapeutic effect [chemodynamic therapy (CDT) + PDT]. The ICG accumulated in tumor tissues exerts a synergistic PDT/photothermal therapy (PTT) effect through single laser irradiation, improving efficiency and reducing side effects. The cell membrane encapsulation increases nanomedicine accumulation in tumor tissues and confers an immune evasion ability. In addition, high local temperatures induced by PTT can enhance CDT. These properties of the NP enable full achievement of PTT/PDT/CDT and targeted effects. Results: Mn2+ can serve as a magnetic resonance imaging agent to guide therapy, and ICG can be used for photothermal and fluorescence imaging. After its intravenous injection, M-HMnO2@ICG accumulated effectively at mouse tumor sites; the optimal timing of in-vivo laser treatment could be verified by near-infrared fluorescence, magnetic resonance, and photothermal imaging. The M-HMnO2@ICG NPs had the best antitumor effects among treatment groups under near-infrared light conditions, and showed good biocompatibility. Conclusion: In this study, we designed a nano-biomimetic delivery system that improves hypoxia, responds to the tumor microenvironment, and efficiently loads ICG. It provides a new economical and convenient strategy for synergistic phototherapy and CDT for cervical cancer.


Assuntos
Verde de Indocianina , Compostos de Manganês , Imagem Multimodal , Nanopartículas , Fotoquimioterapia , Fármacos Fotossensibilizantes , Microambiente Tumoral , Neoplasias do Colo do Útero , Neoplasias do Colo do Útero/terapia , Neoplasias do Colo do Útero/diagnóstico por imagem , Neoplasias do Colo do Útero/tratamento farmacológico , Feminino , Microambiente Tumoral/efeitos dos fármacos , Humanos , Verde de Indocianina/química , Verde de Indocianina/farmacologia , Fotoquimioterapia/métodos , Animais , Células HeLa , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/química , Nanopartículas/química , Compostos de Manganês/química , Compostos de Manganês/farmacologia , Camundongos , Imagem Multimodal/métodos , Terapia Fototérmica/métodos , Óxidos/química , Óxidos/farmacologia , Camundongos Endogâmicos BALB C , Poliaminas/química , Poliaminas/farmacologia , Imageamento por Ressonância Magnética/métodos
8.
PLoS One ; 19(6): e0305611, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38885268

RESUMO

In this study, a simple calcination route was adopted to prepare hausmannite Mn3O4 nanoparticles using rice powder as soft bio-template. Prepared Mn3O4 was characterized by Fourier Transform Infra-Red Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray microanalysis (EDX), Powder X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Brunauer-Emmett-Teller (BET) and Solid state UV-Vis spectroscopic techniques. Mn-O stretching in tetrahedral site was confirmed by FTIR and Raman spectra. % of Mn and O content supported Mn3O4 formation. The crystallinity and grain size was found to be 68.76% and 16.43 nm, respectively; tetragonal crystal system was also cleared by XRD. TEM clarified the planes of crystal formed which supported the XRD results and BET demonstrated mesoporous nature of prepared Mn3O4 having low pore volume. Low optical band gap of 3.24 eV of prepared Mn3O4 nanoparticles indicated semiconductor property and was used as cathode material to fabricate CR-2032 coin cell of Aqueous Rechargeable Zinc Ion Battery (ARZIB). A reversible cyclic voltammogram (CV) showed good zinc ion storage performance. Low cell resistance was confirmed by Electrochemical Impedance Spectroscopy (EIS). The coin cell delivered high specific discharge capacity of 240.75 mAhg-1 at 0.1 Ag-1 current density. The coulombic efficiency was found to be 99.98%. It also delivered excellent capacity retention 94.45% and 64.81% after 300 and 1000 charge-discharge cycles, respectively. This work offers a facile and cost effective approach for preparing cathode material of ARZIBs.


Assuntos
Fontes de Energia Elétrica , Compostos de Manganês , Nanopartículas , Oryza , Óxidos , Pós , Zinco , Oryza/química , Compostos de Manganês/química , Zinco/química , Óxidos/química , Nanopartículas/química , Difração de Raios X , Espectroscopia de Infravermelho com Transformada de Fourier
9.
ACS Appl Mater Interfaces ; 16(24): 31807-31816, 2024 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-38847366

RESUMO

Wearable smart textile sensors for monitoring vital signs are fast, noninvasive, and highly desirable for personalized health management to diagnose health anomalies such as cardiovascular diseases and respiratory dysfunction. Traditional biosignal sensors, with power consumption issues, constrain the use of wearable medical devices. This study introduces an autonomous triboelectric smart textile sensor (AUTS) made of reduced graphene oxide/manganese dioxide/polydimethylsiloxane (RGO-M-PDMS) and polytetrafluoroethylene (TEFLON)-knitted silver electrode, offering promise for vital sign monitoring with self-powering, flexibility, and wearability. The sensor exhibits impressive output performance, with a sensitivity of 7.8 nA/kPa, response time of ≈40 ms, good stability of >15,000 cycles, stretchability of up to 40%, and machine washability of >20 washes. The AUTS has been integrated to the TriBreath respiratory belt for monitoring respiratory signals and pulse strap for pulse signals concurrently at different body pulse points. These sensors wirelessly transmitted the acquired biosignals to a smartphone, demonstrating the potential of a self-powered and real-time vital sign monitoring system.


Assuntos
Grafite , Óxidos , Têxteis , Sinais Vitais , Dispositivos Eletrônicos Vestíveis , Grafite/química , Humanos , Monitorização Fisiológica/instrumentação , Monitorização Fisiológica/métodos , Óxidos/química , Compostos de Manganês/química , Dimetilpolisiloxanos/química , Politetrafluoretileno/química , Eletrodos , Prata/química
10.
J Nanobiotechnology ; 22(1): 346, 2024 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-38898493

RESUMO

Chemoresistance remains a significant challenge for effective breast cancer treatment which leads to cancer recurrence. CRISPR-directed gene editing becomes a powerful tool to reduce chemoresistance by reprogramming the tumor microenvironment. Previous research has revealed that Chinese herbal extracts have significant potential to overcome tumor chemoresistance. However, the therapeutic efficacy is often limited due to their poor tumor targeting and in vivo durability. Here we have developed a tumor microenvironment responsive nanoplatform (H-MnO2(ISL + DOX)-PTPN2@HA, M(I + D)PH) for nano-herb and CRISPR codelivery to reduce chemoresistance. Synergistic tumor inhibitory effects were achieved by the treatment of isoliquiritigenin (ISL) with doxorubicin (DOX), which were enhanced by CRISPR-based gene editing to target protein tyrosine phosphatase non-receptor type 2 (PTPN2) to initiate long-term immunotherapy. Efficient PTPN2 depletion was observed after treatment with M(I + D)PH nanoparticles, which resulted in the recruitment of intratumoral infiltrating lymphocytes and an increase of proinflammatory cytokines in the tumor tissue. Overall, our nanoparticle platform provides a diverse technique for accomplishing synergistic chemotherapy and immunotherapy, which offers an effective treatment alternative for malignant neoplasms.


Assuntos
Doxorrubicina , Imunoterapia , Microambiente Tumoral , Microambiente Tumoral/efeitos dos fármacos , Animais , Imunoterapia/métodos , Doxorrubicina/farmacologia , Humanos , Camundongos , Linhagem Celular Tumoral , Feminino , Camundongos Endogâmicos BALB C , Nanopartículas/química , Neoplasias da Mama/terapia , Neoplasias da Mama/tratamento farmacológico , Edição de Genes/métodos , Sistemas CRISPR-Cas , Compostos de Manganês/química , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Sistemas de Liberação de Medicamentos , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Antineoplásicos/farmacologia , Antineoplásicos/química , Óxidos
11.
Microbes Environ ; 39(2)2024.
Artigo em Inglês | MEDLINE | ID: mdl-38866480

RESUMO

Mn(II)-oxidizing microorganisms are considered to play significant roles in the natural geochemical cycles of Mn and other heavy metals because the insoluble biogenic Mn oxides (BMOs) that are produced by these microorganisms adsorb other dissolved heavy metals and immobilize them as precipitates. In the present study, a new Mn(II)-oxidizing fungal strain belonging to the ascomycete genus Periconia, a well-studied plant-associating fungal genus with Mn(II)-oxidizing activity that has not yet been exami-ned in detail, was isolated from natural groundwater outflow sediment. This isolate, named strain TS-2, was confirmed to oxidize dissolved Mn(II) and produce insoluble BMOs that formed characteristic, separately-located nodules on their hyphae while leaving major areas of the hyphae free from encrustation. These BMO nodules also adsorbed and immobilized dissolved Cu(II), a model analyte of heavy metals, as evidenced by elemental mapping ana-lyses of fungal hyphae-BMO assemblages using a scanning electron microscope with energy-dispersive X-ray spectroscopy (SEM-EDX). Analyses of functional genes within the whole genome of strain TS-2 further revealed the presence of multiple genes predicted to encode laccases/multicopper oxidases that were potentially responsible for Mn(II) oxidation by this strain. The formation of BMO nodules may have functioned to prevent the complete encrustation of fungal hyphae, thereby enabling the control of heavy metal concentrations in their local microenvironments while maintaining hyphal functionality. The present results will expand our knowledge of the physiological and morphological traits of Mn(II)-oxidizing Periconia, which may affect the natural cycle of heavy metals through their immobilization.


Assuntos
Cobre , Hifas , Compostos de Manganês , Óxidos , Hifas/metabolismo , Hifas/crescimento & desenvolvimento , Cobre/metabolismo , Compostos de Manganês/metabolismo , Óxidos/metabolismo , Óxidos/química , Ascomicetos/genética , Ascomicetos/metabolismo , Ascomicetos/química , Oxirredução , Água Subterrânea/microbiologia , Água Subterrânea/química , Filogenia , Sedimentos Geológicos/microbiologia , Microscopia Eletrônica de Varredura , Manganês/metabolismo
12.
Environ Sci Technol ; 58(23): 10398-10408, 2024 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-38803193

RESUMO

It is a great challenge to remove VOCs and NOx simultaneously from flue gas in nonelectric industries. This study focuses on the construction of Fe-MnO2 catalysts that perform well in the simultaneous removal of toluene and NOx at low temperatures. Utilizing the Fe-induced phase transition of MnO2, Fe-MnO2-F&R catalysts with a composite morphology of nanoflowers and nanorods were successfully prepared that provided an abundant microporous structure to facilitate the diffusion of molecules of different sizes. Through in-depth investigation of the active sites and reaction mechanism, we discovered that Fe-induced phase transition could modulate the surface acidity of Fe-MnO2-F&R. The higher concentration of surface Mn4+ provided numerous Brønsted acid sites, which effectively promoted the activation of toluene to reactive intermediates, such as benzyl alcohol/benzoate/maleic acid. Simultaneously, Fe provided a large number of Lewis acid sites that anchor and activate NH3 species, thereby inhibiting NH3 nonselective oxidation. Furthermore, additional Brønsted acid sites were generated during the simultaneous reaction process, enhancing toluene activation. Consequently, the simultaneous removal of toluene and NOx was achieved through regulation of the physical structure and the concentration of acidic sites. The present work provides new insights into the rational design of bifunctional catalysts for the synergistic control of VOCs and NOx emissions.


Assuntos
Tolueno , Tolueno/química , Compostos de Manganês/química , Catálise , Óxidos/química , Transição de Fase , Óxidos de Nitrogênio/química , Temperatura Baixa
13.
Chemosphere ; 360: 142392, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38777195

RESUMO

Significant challenges remain for the remediation of chlorinated-solvent plumes in groundwater, such as trichloroethene (TCE) and tetrachloroethene (PCE). A novel slow-release permanganate gel (SRP-G) technique may show promise for the in-situ treatment (remediation) of chlorinated contaminant plumes in groundwater. A series of laboratory experiments were conducted to characterize the primary physical factors that influence SRP-G gelation processes to optimize SRP-G performance for plume treatment. Specifically, experiments were conducted to quantify gel zeta potential, particle size distribution, and viscosity to determine SRP-G gelation characteristics and processes. These experiments tested various concentrations of two SRP-G amendment solutions (NaMnO4 and KMnO4) prepared with 30-wt.% and 50-wt.% colloidal silica to determine such influences on zeta potential, particle size distribution, and viscosity. The results of this study show that SRP-G solutions with low zeta potential and relatively high pH favor more rapid SRP-G gelation. The concomitant interaction of the predominantly negatively charged colloidal silica particles and the positively charged dissociated cations (Na+ and K+) in the SRP-G solution had the effect of stabilizing charge imbalance via attraction of particles and thereby inducing a greater influence on the gelation process. Gel particle size distribution and changes in viscosity had a significant influence on SRP-G solution gelation. The addition of permanganate (NaMnO4 or KMnO4) increased the average particle size distribution and the viscosity of the SRP-G solution and decreased the overall gelation time. SRP-G amendments (NaMnO4 or KMnO4) prepared with 50-wt.% colloidal silica showed more effective gelation (and reduced gelation time) compared to SRP-G amendments prepared with 30-wt.% colloidal silica. Under the conditions of these experiments, it was determined that both the 7-wt.% NaMnO4 solution and 90 mg/L KMnO4 solution using 50-wt.% colloidal silica would be the optimal injection SRP-G solution concentrations for this in-situ treatment technique.


Assuntos
Géis , Água Subterrânea , Compostos de Manganês , Óxidos , Solventes , Poluentes Químicos da Água , Poluentes Químicos da Água/química , Poluentes Químicos da Água/análise , Água Subterrânea/química , Géis/química , Solventes/química , Compostos de Manganês/química , Óxidos/química , Recuperação e Remediação Ambiental/métodos , Tricloroetileno/química , Halogenação , Viscosidade , Tamanho da Partícula , Tetracloroetileno/química , Tetracloroetileno/análise
14.
Spectrochim Acta A Mol Biomol Spectrosc ; 318: 124493, 2024 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-38796891

RESUMO

6-mercaptopurine (6-MP) is widely used in the treatment of many diseases, but exhibits some serious side effects due to its toxicity. Therefore, it is important and imperative to effectively control and monitoring concentration of 6-MP. Herein, we designed a smartphone-assisted colorimetric sensing platform for 6-MP detection, based on an excellent ß-cyclodextrin modified MnO2 nanosheets (ß-CD@MnO2 NNS) mediated oxidase-like activity. ß-CD@MnO2 NNS can directly oxidizes 3,3',5,5'-tetramethylbenzidine (TMB) into oxidized TMB with color changes, yielding more than 3-fold higher oxidase-like catalytic activity compared with individual MnO2 NNS. After adding 6-MP, ß-CD@MnO2 NNS can be reduced to Mn2+ and lose their oxidase-like properties, resulting in a color and absorbance change for sensitive and selectivity detection of 6-MP. Meanwhile, the smartphone-based color recognition application can intuitively and simply measure the concentration of 6-MP. The limits of detection UV-vis instrument and smartphone were 0.35 µM and 0.86 µM, respectively. This method has also been successfully applied to the detection of real samples. Finally, this study provides a new promising platform for detection of 6-MP and is expected to be used in application of pharmaceutical analysis and biomedicine.


Assuntos
Colorimetria , Compostos de Manganês , Mercaptopurina , Nanoestruturas , Óxidos , Smartphone , beta-Ciclodextrinas , Colorimetria/métodos , Compostos de Manganês/química , beta-Ciclodextrinas/química , Óxidos/química , Mercaptopurina/análise , Nanoestruturas/química , Oxirredutases/metabolismo , Oxirredutases/química , Limite de Detecção , Humanos , Benzidinas/química
15.
Inorg Chem ; 63(23): 10542-10556, 2024 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-38805686

RESUMO

Over decades, nanozyme has served as a better replacement of bioenzymes and fulfills most of the shortcomings and intrinsic disadvantages of bioenzymes. Recently, manganese-based nanomaterials have been highly noticed for redox-modulated multienzyme mimicking activity and wide applications in biosensing and biomedical science. The redox-modulated multienzyme mimicking activity was highly in tune with their size, surface functionalization, and charge on the surface and phases. On the subject of calcination temperature to Mn3O4 nanoparticles (NPs), its phase has been transformed to Mn2O3 NPs and Mn5O8 NPs upon different calcination temperatures. Assigning precise structure-property connections is made easier by preparing the various manganese oxides in a single step. The present study has focused on the variation of multienzyme mimicking activity with different phases of Mn3O4 NPs, so that they can be equipped for multifunctional activity with greater potential. Herein, spherical Mn3O4 NPs have been synthesized via a one-step coprecipitation method, and other phases are obtained by direct calcination. The calcination temperature varies to 100, 200, 400, and 600 °C and the corresponding manganese oxide NPs are named M-100, M-200, M-400, and M-600, respectively. The phase transformation and crystalline structure are evaluated by powder X-ray diffraction and selected-area electron diffraction analysis. The different surface morphologies are easily navigated by Fourier transform infrared, field-emission scanning electron microscopy, and high-resolution transmission electron microscopy analysis. Fortunately, for the mixed valence state of Mn3O4 NPs, all phases of manganese oxide NPs showed multienzyme mimicking activity including superoxide dismutase (SOD), catalase, oxidase (OD), and peroxidase; therefore, it offers a synergistic antioxidant ability to overexpose reactive oxygen species. Mn3O4 NPs exhibited good SOD-like enzyme activity, which allowed it to effectively remove the active oxygen (O2•-) from cigarette smoke. A sensitive colorimetric sensor with a low detection limit and a promising linear range has been designed to detect two isomeric phenolic pollutants, hydroquinone (H2Q) and catechol (CA), by utilizing optimized OD activity. The current probe has outstanding sensitivity and selectivity as well as the ability to visually detect two isomers with the unaided eye.


Assuntos
Colorimetria , Compostos de Manganês , Óxidos , Temperatura , Óxidos/química , Compostos de Manganês/química , Catálise , Colorimetria/métodos , Espécies Reativas de Oxigênio/metabolismo , Espécies Reativas de Oxigênio/análise , Propriedades de Superfície
16.
J Chromatogr A ; 1728: 464987, 2024 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-38821034

RESUMO

In this work, we proposed an indirect phase-conversion strategy to construct a new approach for accurately and efficiently determining the permanganate index in water samples via headspace GC measurement. After the reducible substances in water reacted with excess potassium permanganate, the remaining potassium permanganate underwent a reaction with sodium oxalate under acidic conditions. The carbon dioxide generated from the gas-evolving reaction was then analyzed by headspace GC. Our findings showed that this new approach boasts high precision (relative standard deviation ≤ 2.18%) and accuracy for permanganate index analysis, thus validating the effectiveness of this new method in analyzing permanganate index. The introduction of the indirect phase-conversion strategy in this study is expected to set a precedent for further advancements in methodologies designed to indirectly evaluate substances capable of undergoing gas-producing reactions.


Assuntos
Óxidos , Poluentes Químicos da Água , Óxidos/química , Poluentes Químicos da Água/análise , Cromatografia Gasosa/métodos , Permanganato de Potássio/química , Compostos de Manganês/química , Dióxido de Carbono/análise , Dióxido de Carbono/química , Água/química
17.
ACS Appl Bio Mater ; 7(6): 4116-4132, 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38772009

RESUMO

The management of multibacterial infections remains clinically challenging in the care and treatment of chronic diabetic wounds. Photodynamic therapy (PDT) offers a promising approach to addressing bacterial infections. However, the limited target specificity and internalization properties of traditional photosensitizers (PSs) toward Gram-negative bacteria pose significant challenges to their antibacterial efficacy. In this study, we designed an iron heme-mimetic PS (MnO2@Fe-TCPP(Zn)) based on the iron dependence of bacteria that can be assimilated by bacteria and retained in different bacteria strains (Escherichia coli, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus) and which shows high PDT antibacterial efficacy. For accelerated wound healing after antibacterial treatment, MnO2@Fe-TCPP(Zn) was loaded into a zwitterionic hydrogel with biocompatibility and antifouling properties to form a nanocomposite antibacterial hydrogel (PSB-MnO2@Fe-TCPP(Zn)). In the multibacterial infectious diabetic mouse wound model, the PSB-MnO2@Fe-TCPP(Zn) hydrogel dressing rapidly promoted skin regeneration by effectively inhibiting bacterial infections, eliminating inflammation, and promoting angiogenesis. This study provides an avenue for developing broad-spectrum antibacterial nanomaterials for combating the antibiotic resistance crisis and promoting the healing of complex bacterially infected wounds.


Assuntos
Antibacterianos , Materiais Biocompatíveis , Testes de Sensibilidade Microbiana , Fotoquimioterapia , Fármacos Fotossensibilizantes , Cicatrização , Cicatrização/efeitos dos fármacos , Animais , Camundongos , Antibacterianos/farmacologia , Antibacterianos/química , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/farmacologia , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Heme/química , Teste de Materiais , Ferro/química , Escherichia coli/efeitos dos fármacos , Tamanho da Partícula , Diabetes Mellitus Experimental/tratamento farmacológico , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Compostos de Manganês/química , Compostos de Manganês/farmacologia
18.
Anal Biochem ; 692: 115572, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38777290

RESUMO

Deoxynivalenol (DON) is a common mycotoxin in food that mainly pollutes grain crops and feeds, such as barley, wheat and corn. DON has caused widespread concern in the field of food and feed safety. In this study, a colorimetric immunoassay was proposed based on the aggregation of gold nanoparticles (AuNPs) due to the decomposition of Mn2+ from gold-coated manganese dioxide (AuNP@MnO2) nanosheets. In this study, 2-(dihydrogen phosphate)-l-ascorbic acid (AAP) was hydrolyzed by alkaline phosphatase (ALP) and converted to ascorbic acid (AA). Then, AuNP@MnO2 was reduced to Mn2+ and AuNPs aggregation occurred. Using the unique optical characteristics of AuNPs and AuNP@MnO2, visible color changes realized simple detection of DON with high sensitivity and portability. With increasing DON content, the color changed more obviously. To quantitatively detect DON, pictures can be taken and the blue value can be read by a smartphone. The detection limit (Ic10) of this method was 0.098 ng mL-1, which was 326 times higher than that of traditional competitive ELISA, and the detection range was 0.177-6.073 ng mL-1. This method exhibited high specificity with no cross-reaction in other structural analogs. The average recovery rate of DON in corn flour samples was 89.1 %-110.2 %, demonstrating the high accuracy and stability of this assay in actual sample detection. Therefore, the colorimetric immunoassay can be used for DON-related food safety monitoring.


Assuntos
Colorimetria , Ouro , Manganês , Nanopartículas Metálicas , Smartphone , Tricotecenos , Colorimetria/métodos , Ouro/química , Tricotecenos/análise , Tricotecenos/química , Nanopartículas Metálicas/química , Imunoensaio/métodos , Manganês/química , Compostos de Manganês/química , Contaminação de Alimentos/análise , Óxidos/química , Limite de Detecção
19.
Talanta ; 276: 126290, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-38805755

RESUMO

A very sensitive electrochemical biosensor, with haemoglobin (Hb) as its basis, has been created to quantify hydrogen peroxide (H2O2), an essential marker in environmental monitoring, food safety, and medical diagnosis. The sensor uses a simple, eco-friendly preparation method. Hb was immobilised on manganese dioxide nanostructure/gold nanoparticles/poly-diallydimethylammonium chloride-functionalised multiwalled carbon nanotubes (PDDA-MWCNT/AuNP/MnO2), characterised using various techniques: amperometry, voltammetry, X-ray diffraction (XRD), and transmission electron microscopy (TEM). Nafion was used as a binder membrane to preserve the biological and electrochemical properties of the protein on the modified electrode. In comparison to earlier research, the novel biosensor had a lower detection limit (1.83 µM) and a limit of quantification (6.11 µM) (S/N = 3) for H2O2. It also exhibited notable reproducibility, long-term stability, and repeatability. It was effectively used to measure the amount of H2O2 in cow milk and orange juice, yielding recoveries in the order of 98.90-99.53 % with RSDs less than 5.0 %, which makes it a promising biosensor for food control.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Ouro , Hemoglobinas , Peróxido de Hidrogênio , Compostos de Manganês , Nanopartículas Metálicas , Leite , Nanotubos de Carbono , Óxidos , Compostos de Amônio Quaternário , Peróxido de Hidrogênio/química , Peróxido de Hidrogênio/análise , Ouro/química , Hemoglobinas/análise , Hemoglobinas/química , Técnicas Biossensoriais/métodos , Compostos de Manganês/química , Nanopartículas Metálicas/química , Compostos de Amônio Quaternário/química , Nanotubos de Carbono/química , Óxidos/química , Técnicas Eletroquímicas/métodos , Leite/química , Animais , Polietilenos/química , Bovinos , Sucos de Frutas e Vegetais/análise , Limite de Detecção , Eletrodos
20.
Bioresour Technol ; 403: 130874, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38782191

RESUMO

Despite the great potential of sulfur-based autotrophic denitrification, an improvement in nitrate removal rate is still needed. This study used the desulfurized products of Mn ore to develop the MnS-S0-limestone autotrophic denitrification system (MSLAD). The feasibility of MSLAD for denitrification was explored and the possible mechanism was proposed. The nitrate (100 mg/L) was almost removed within 24 h in batch experiment in MSLAD. Also, an average TN removal of 98 % (472.0 mg/L/d) at hydraulic retention time of 1.5 h in column experiment (30 mg/L) was achieved. MnS and S0 could act as coupled electron donors and show synergistic effects for nitrate removal. γ-MnS with smaller particle size and lower crystallinity was more readily utilized by the bacterium and had higher nitrate removal efficiency than that of α-MnS. Thiobacillus and Sulfurimonas were the core functional bacterium in denitrification. Therefore, MnS-S0-limestone bio-denitrification provides an efficient alternative method for nitrate removal in wastewater.


Assuntos
Processos Autotróficos , Carbonato de Cálcio , Desnitrificação , Nitratos , Enxofre , Nitratos/metabolismo , Carbonato de Cálcio/química , Enxofre/metabolismo , Sulfetos/química , Sulfetos/metabolismo , Estudos de Viabilidade , Thiobacillus/metabolismo , Compostos de Manganês/química , Purificação da Água/métodos , Manganês
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...