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1.
Molecules ; 26(12)2021 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-34204215

RESUMO

Recently, the development of nanocatalysts based on naturally occurring polysaccharides has received a lot of attention. Chitosan (CS), as a biodegradable and biocompatible polysaccharide, is considered to be an excellent template for the design of a hybrid biopolymer-based metal oxide nanocomposite. In this case, lanthanum oxide nanoparticles doped with chitosan at different weight percentages (5, 10, 15, and 20 wt% CS/La2O3) were prepared via a simple solution casting method. The prepared CS/La2O3 nanocomposite solutions were cast in a Petri dish in order to produce the developed catalyst, which was shaped as a thin film. The structural features of the hybrid nanocomposite film were studied by FTIR, SEM, and XRD analytical tools. FTIR spectra confirmed the presence of the major characteristic peaks of chitosan, which were modified by interaction with La2O3 nanoparticles. Additionally, SEM graphs showed dramatic morphological changes on the surface of chitosan, which is attributed to surface adsorption with La2O3 molecules. The prepared CS/La2O3 nanocomposite film (15% by weight) was investigated as an effective, recyclable, and heterogeneous base catalyst in the synthesis of pyridines and pyrazoles. The nanocomposite used was sufficiently stable and was collected and reused more than three times without loss of catalytic activity.


Assuntos
Quitosana/química , Pirazóis/química , Piridinas/química , Antibacterianos/química , Catálise , Lantânio/química , Nanocompostos/química , Nanopartículas/química , Óxidos/química
2.
Int J Mol Sci ; 22(11)2021 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-34199667

RESUMO

Nanoparticles (NPs) with a high atomic number (Z) are promising radiosensitizers for cancer therapy. However, the dependence of their efficacy on irradiation conditions is still unclear. In the present work, 11 different metal and metal oxide NPs (from Cu (ZCu = 29) to Bi2O3 (ZBi = 83)) were studied in terms of their ability to enhance the absorbed dose in combination with 237 X-ray spectra generated at a 30-300 kVp voltage using various filtration systems and anode materials. Among the studied high-Z NP materials, gold was the absolute leader by a dose enhancement factor (DEF; up to 2.51), while HfO2 and Ta2O5 were the most versatile because of the largest high-DEF region in coordinates U (voltage) and Eeff (effective energy). Several impacts of the X-ray spectral composition have been noted, as follows: (1) there are radiation sources that correspond to extremely low DEFs for all of the studied NPs, (2) NPs with a lower Z in some cases can equal or overcome by the DEF value the high-Z NPs, and (3) the change in the X-ray spectrum caused by a beam passing through the matter can significantly affect the DEF. All of these findings indicate the important role of carefully planning radiation exposure in the presence of high-Z NPs.


Assuntos
Cobre/uso terapêutico , Nanopartículas Metálicas/uso terapêutico , Neoplasias/radioterapia , Radiossensibilizantes/uso terapêutico , Bismuto/química , Bismuto/uso terapêutico , Cobre/química , Relação Dose-Resposta a Droga , Humanos , Nanopartículas Metálicas/química , Método de Monte Carlo , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Óxidos/química , Óxidos/uso terapêutico , Radiossensibilizantes/química , Dosagem Radioterapêutica
3.
Ecotoxicol Environ Saf ; 221: 112451, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34174737

RESUMO

Manganese oxides and iron oxides have been widely introduced in constructed wetlands (CWs) for sewage treatment due to their extensiveness in nature and their ability to participate in various reactions, but their effects on greenhouse gas (GHG) emissions remain unclear. Here, a set of vertical subsurface-flow CWs (Control, Fe-VSSCWs, and Mn-VSSCWs) was established to comprehensively evaluate which are the better metal substrate materials for CWs, iron oxides or manganese oxides, through water quality and the global warming potential (GWP) of nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2). The results revealed that the removal efficiencies of chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) in Mn-VSSCWs were all higher than that in Fe-VSSCWs, and manganese oxides could almost completely suppress the CH4 production and reduce GWP (from 8.15 CO2-eq/m2/h to 7.17 mg CO2-eq/m2/h), however, iron oxides promoted GWP (from 8.15 CO2-eq/m2/h to 10.84 mg CO2-eq/m2/h), so manganese oxides are the better CW substrate materials to achieve effective sewage treatment while reducing the greenhouse gas effect.


Assuntos
Poluentes Atmosféricos/química , Compostos Férricos/química , Efeito Estufa/prevenção & controle , Compostos de Manganês/química , Óxidos/química , Purificação da Água/métodos , Áreas Alagadas , Análise da Demanda Biológica de Oxigênio , Dióxido de Carbono/química , Metano/química , Nitrogênio/química , Óxido Nitroso/química , Fósforo/química , Poluentes da Água/química , Qualidade da Água
4.
Int J Mol Sci ; 22(11)2021 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-34073002

RESUMO

For the development of next-generation protein-based biosensor surfaces, it is important to understand how functional proteins, such as fibrinogen (FBG), interact with polar substrate surfaces in order to prepare highly sensitive points of medical care diagnostics. FBG, which is a fibrous protein with an extracellular matrix, has both positively and negatively charged regions on its 3-dimensional surface, which makes interpreting how it effectively binds to polarized surfaces challenging. In this study, single-crystal LiNbO3 (LNO) substrates that have surface charges were used to investigate the adsorption of FBG protruding polar fragments on the positively and negatively charged LNO surfaces. We performed a combination of experiments and multi-scale molecular modeling to understand the binding of FBG in vacuum and water-solvated surfaces of LNO. XPS measurements showed that the FBG adsorption on LNO increased with increment in solution concentration on surfaces independent of charges. Multi-scale molecular modeling employing Quantum Mechanics, Monte Carlo, and Molecular Mechanics addressed the phenomenon of FBG fragment bonding on LNO surfaces. The binding simulation validated the experimental observation using zeta potential measurements which showed presence of solvated medium influenced the adsorption phenomenon due to the negative surface potential.


Assuntos
Fibrinogênio , Nióbio , Óxidos , Adsorção , Fibrinogênio/química , Fibrinogênio/metabolismo , Modelos Moleculares , Nióbio/química , Nióbio/metabolismo , Óxidos/química , Óxidos/metabolismo , Ligação Proteica , Propriedades de Superfície , Água/química
5.
Ecotoxicol Environ Saf ; 220: 112373, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34058675

RESUMO

The electronic conductivity of the metal oxides is generally increased by hybridization of highly conductive carbon supportive materials. In this present work, we have demonstrated a novel one-pot preparation of cerium niobate (CeNbO4) nanoparticles embedded with graphene oxide (GO/CeNbO4) composite, for ultrasensitive detection of the photographic developing agent, metol (MTL). The as-prepared GO/CeNbO4 was analyzed by various characterization techniques. The intensive characterization techniques were used to affirm the detailed structural moiety, size, morphology, and surface area of GO/CeNbO4. The GO/CeNbO4 modified glassy carbon electrode (GCE) affords a superior electrocatalytic activity toward MTL. The obtained amperometric response on the GO/CeNbO4/GCE holding an extremely low level detection of 10 nM and superior sensitivity of 10.97 µA µM-1 cm-2 toward MTL detection. Besides, the GO/CeNbO4/GCE also gives excellent selectivity, stability, repeatability, and reproducibility. We achieved excellent recovery results in real photographic solution and river water samples analysis with great accuracy. This work offers a novel insight into the growth of the carbon-based niobate family with electrochemical sensor applications.


Assuntos
Aminofenóis/análise , Técnicas Eletroquímicas/métodos , Monitoramento Ambiental/métodos , Poluentes Ambientais/análise , Nanocompostos/química , Rios/química , Sulfatos/análise , Carbono/química , Catálise , Cério/química , Eletricidade , Eletrodos , Grafite/química , Indústrias , Nanopartículas/química , Nióbio/química , Óxidos/química , Compostos de Oxigênio/química , Fotografação , Reprodutibilidade dos Testes , Soluções , Água/química
6.
Artigo em Inglês | MEDLINE | ID: mdl-33979267

RESUMO

The popularity of nanotechnology results from the possibility of obtaining materials that have better chemical, electrical, thermal, mechanical, or optical properties. Nano-sized materials are characterized by an increased surface area, which improves their chemical reactivity and mobility. Due to their enhanced reactivity and appropriately small size, some nanoparticles are used as antimicrobial and antifungal agents. Nanoparticles exhibit antimicrobial potential through multifaceted mechanisms. The adhesion of nanoparticles to microbial cells, and reactive oxygen species, and their penetration inside the cells, have been recognized as the most prominent modes of antimicrobial action. This review presents the mechanism of action of nanometals and oxide nanoparticles used as antimicrobials and the mechanisms of bacterial resistance to the toxic effects of nanoparticles. The article presents methods of forming microorganism resistance to the toxic effects of nanoparticles and the negative impact of nanoparticles on human health.


Assuntos
Anti-Infecciosos/farmacologia , Nanopartículas/química , Nanopartículas/toxicidade , Anti-Infecciosos/química , Anti-Infecciosos/toxicidade , Humanos , Óxidos/química
7.
Nat Commun ; 12(1): 3037, 2021 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-34031392

RESUMO

Microbialites accrete where environmental conditions and microbial metabolisms promote lithification, commonly through carbonate cementation. On Little Ambergris Cay, Turks and Caicos Islands, microbial mats occur widely in peritidal environments above ooid sand but do not become lithified or preserved. Sediment cores and porewater geochemistry indicated that aerobic respiration and sulfide oxidation inhibit lithification and dissolve calcium carbonate sand despite widespread aragonite precipitation from platform surface waters. Here, we report that in tidally pumped environments, microbial metabolisms can negate the effects of taphonomically-favorable seawater chemistry on carbonate mineral saturation and microbialite development.


Assuntos
Compostos de Cálcio/química , Ecossistema , Óxidos/química , Areia/química , Areia/microbiologia , Carbonato de Cálcio/metabolismo , Carbonatos , Sedimentos Geológicos/química , Sedimentos Geológicos/microbiologia , Microbiota , Minerais , Água do Mar/química , Água do Mar/microbiologia , Índias Ocidentais
8.
Chem Pharm Bull (Tokyo) ; 69(4): 303-313, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33790076

RESUMO

Non-canonical amino acid derivatives are an attractive scaffold for novel drug candidates. Among the methods used to prepare this motif, the asymmetric Mannich-type reaction of α-imino carboxylic acid derivatives is a preeminent strategy because a wide variety of non-canonical amino acids can be accessed by changing only the nucleophile. Preparing the common substrate is difficult, however, which makes this method problematic. We developed a convenient method for synthesizing common substrates using MnO2-mediated oxidation of stable precursors. Peptides bearing non-canonical amino acids are another attractive synthetic target. We propose a new approach for synthesizing non-canonical amino acid-containing peptides by directly applying various organic reactions to peptidic substrates. Using hydrophobic anchor-supported peptides, we directly applied ring-closing metathesis and asymmetric Friedel-Crafts reactions to peptidic substrates. We also developed a novel recyclable organocatalyst according to the nature of the hydrophobic anchor tagged compound.


Assuntos
Aminoácidos/síntese química , Técnicas de Química Sintética/métodos , Peptídeos/síntese química , Preparações Farmacêuticas/síntese química , Aminoácidos/química , Catálise , Descoberta de Drogas/métodos , Compostos de Manganês/química , Oxirredução , Óxidos/química , Peptídeos/química , Preparações Farmacêuticas/química
9.
Int J Biol Macromol ; 182: 722-729, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33862074

RESUMO

Designing of eco-friendly, low cost, and thermally stable stabilizing/supporting agents are always desired for production of catalyst systems which provide good catalytic performance in organic reactions. In this study, a novel, green, and efficient stabilizer containing chitosan/Co3O4 microspheres (CS/Co3O4) was developed. Palladium nanoparticles (Pd NPs) were then successfully immobilized on CS/Co3O4 as a heterogeneous nanocatalyst (Pd NPs/CS/Co3O4). Characterization of the designed materials were performed by FT-IR, TEM, FE-SEM, XRD, and EDS and it was determined that Pd NPs formed as approximately 20 nm. Catalytic behavior of Pd NPs/CS/Co3O4 was investigated in the production of different substituted benzonitriles via aryl halide cyanation. Catalytic studies indicate that electron-rich or poor aromatic halides were smoothly cyanated with good reaction yields by Pd NPs/CS/Co3O4 nanocatalyst by using K4[Fe(CN)6] as the cyanating agent. Moreover, it was found that Pd NPs/CS/Co3O4 nanocatalyst provided not only good reaction yields and but also good recovery/reusability for six times in the aryl halide cyanations. This paper displays that Pd NPs/CS/Co3O4 nanocatalyst has a great catalytic and recycling potential for aryl halide cyanations.


Assuntos
Quitosana/análogos & derivados , Cobalto/química , Nanopartículas/química , Nitrilas/síntese química , Óxidos/química , Paládio/química , Catálise , Microesferas
10.
Int J Mol Sci ; 22(7)2021 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-33804997

RESUMO

Over the last years, different nanomaterials have been investigated to design highly selective and sensitive sensors, reaching nano/picomolar concentrations of biomolecules, which is crucial for medical sciences and the healthcare industry in order to assess physiological and metabolic parameters. The discovery of graphene (G) has unexpectedly impulsed research on developing cost-effective electrode materials owed to its unique physical and chemical properties, including high specific surface area, elevated carrier mobility, exceptional electrical and thermal conductivity, strong stiffness and strength combined with flexibility and optical transparency. G and its derivatives, including graphene oxide (GO) and reduced graphene oxide (rGO), are becoming an important class of nanomaterials in the area of optical and electrochemical sensors. The presence of oxygenated functional groups makes GO nanosheets amphiphilic, facilitating chemical functionalization. G-based nanomaterials can be easily combined with different types of inorganic nanoparticles, including metals and metal oxides, quantum dots, organic polymers, and biomolecules, to yield a wide range of nanocomposites with enhanced sensitivity for sensor applications. This review provides an overview of recent research on G-based nanocomposites for the detection of bioactive compounds, providing insights on the unique advantages offered by G and its derivatives. Their synthesis process, functionalization routes, and main properties are summarized, and the main challenges are also discussed. The antioxidants selected for this review are melatonin, gallic acid, tannic acid, resveratrol, oleuropein, hydroxytyrosol, tocopherol, ascorbic acid, and curcumin. They were chosen owed to their beneficial properties for human health, including antibiotic, antiviral, cardiovascular protector, anticancer, anti-inflammatory, cytoprotective, neuroprotective, antiageing, antidegenerative, and antiallergic capacity. The sensitivity and selectivity of G-based electrochemical and fluorescent sensors are also examined. Finally, the future outlook for the development of G-based sensors for this type of biocompounds is outlined.


Assuntos
Técnicas Biossensoriais , Condutividade Elétrica , Grafite/química , Antioxidantes/química , Ácido Ascórbico/química , Curcumina/química , Eletrodos , Radicais Livres , Ácido Gálico/química , Humanos , Glucosídeos Iridoides/química , Melatonina/química , Metais/química , Nanocompostos/química , Nanoestruturas/química , Óxidos/química , Álcool Feniletílico/análogos & derivados , Álcool Feniletílico/química , Pontos Quânticos , Resveratrol/química , Taninos/química , Tocoferóis/química
11.
Molecules ; 26(5)2021 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-33801328

RESUMO

This study investigates the dissolution behavior of oxide layers containing radionuclides using perfluorocarbon (PFC) emulsion as a reusable medium. Chemicals such as PFC, anionic surfactant, and H2SO4 are used for preparing the PFC emulsion, and emulsified using an ultrasonication process. The FTIR results show O-H stretching that is formed by the interaction of the carboxyl group of the anionic surfactant with the hydroxyl group of water containing H2SO4, and find that the H2SO4 can be homogeneously dispersed in the PFC-anionic surfactant-H2SO4 emulsion. The dissolution test of the simulated Cr2O3 specimen is conducted using PFC emulsion containing KMnO4. Through the weight losses of specimens and Scanning Electron Microscope-Energy Dispersive X-ray Spectrometer (SEM-EDS) analysis, it is confirmed that the Cr2O3 layer on the SUS304 specimen is easily dissolved using PFC emulsion. During the dissolution of the Cr2O3, it is observed that the dispersed H2SO4-KMnO4 became unstable and separated from PFC emulsion. Based on these results, the behavior of the PFC emulsion during the dissolution of the oxide layer is explained.


Assuntos
Emulsões , Fluorcarbonetos/química , Óxidos/química , Tensoativos/química , Água/química
12.
Molecules ; 26(5)2021 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-33801417

RESUMO

Trimethylamine N-oxide (TMAO), as a gut-derived metabolite, has been found to be associated with enhanced risk for atherosclerosis and cardiovascular disease. We presented a method for targeted profiling of TMAO and betaine in serum and food samples based on a combination of one-step sample pretreatment and proton nuclear magnetic resonance spectroscopy. The key step included a processing of sample preparation using a selective solid-phase extraction column for retention of basic metabolites. Proton signals at δ 3.29 and δ 3.28 were employed to quantify TMAO and betaine, respectively. The developed method was examined with acceptable linear relationship, precision, stability, repeatability, and accuracy. It was successfully applied to detect serum levels of TMAO and betaine in TMAO-fed mice and high-fructose-fed rats and also used to determine the contents of TMAO and betaine in several kinds of food, such as fish, pork, milk, and egg yolk.


Assuntos
Betaína/análise , Análise de Alimentos/métodos , Metabolômica/métodos , Metilaminas/análise , Óxidos/química , Animais , Betaína/sangue , Betaína/metabolismo , Feminino , Masculino , Metilaminas/sangue , Metilaminas/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Ratos , Ratos Wistar
13.
Biomed Res Int ; 2021: 6631533, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33816622

RESUMO

Endometrial cancer (EC) is a common gynecological malignancy worldwide whose therapy mainly depends on chemotherapy. In past years, an increasing number of studies indicate that hollow MnO2 could serve as a nanoplatform in the drug delivery system. The Brucea javanica oil emulsion (BJOE) has been illustrated to play a vital role in cancers. However, knowledge about the combined effect of H-MnO2-PEG/BJOE in endometrial cancer remains ambiguous up to now. In the present work, we prepared a drug-delivery vector H-MnO2-PEG by chemical synthesis and found that H-MnO2-PEG significantly inhibited cell proliferation in endometrial cancer cells. Moreover, the combination of H-MnO2-PEG/BJOE could repress cell proliferation more efficiently and promote cell apoptosis. Mechanistically, we found that BJOE exerted its role as a promoter of endometrial apoptosis by regulating relative protein expressions. In general, the present study demonstrates that H-MnO2-PEG functions as a critical vector in the tumor microenvironment of endometrial cancer and the significant effect of H-MnO2-PEG/BJOE on cancer cells, suggesting a new paradigm for the treatment of endometrial cancer.


Assuntos
Apoptose/efeitos dos fármacos , Brucea/química , Proliferação de Células/efeitos dos fármacos , Neoplasias do Endométrio , Compostos de Manganês , Óxidos , Óleos Vegetais , Linhagem Celular Tumoral , Emulsões , Neoplasias do Endométrio/tratamento farmacológico , Neoplasias do Endométrio/metabolismo , Neoplasias do Endométrio/patologia , Feminino , Humanos , Compostos de Manganês/química , Compostos de Manganês/farmacologia , Óxidos/química , Óxidos/farmacologia , Óleos Vegetais/química , Óleos Vegetais/farmacologia
14.
Molecules ; 26(8)2021 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-33920258

RESUMO

Nowadays, the impact of engineered nanoparticles (NPs) on human health and environment has aroused widespread attention. It is essential to assess and predict the biological activity, toxicity, and physicochemical properties of NPs. Computation-based methods have been developed to be efficient alternatives for understanding the negative effects of nanoparticles on the environment and human health. Here, a classification-based structure-activity relationship model for nanoparticles (nano-SAR) was developed to predict the cellular uptake of 109 functionalized magneto-fluorescent nanoparticles to pancreatic cancer cells (PaCa2). The norm index descriptors were employed for describing the structure characteristics of the involved nanoparticles. The Random forest algorithm (RF), combining with the Recursive Feature Elimination (RFE) was employed to develop the nano-SAR model. The resulted model showed satisfactory statistical performance, with the accuracy (ACC) of the test set and the training set of 0.950 and 0.966, respectively, demonstrating that the model had satisfactory classification effect. The model was rigorously verified and further extensively compared with models in the literature. The proposed model could be reasonably expected to predict the cellular uptakes of nanoparticles and provide some guidance for the design and manufacture of safer nanomaterials.


Assuntos
Nanopartículas Metálicas/química , Nanoestruturas/química , Óxidos/química , Relação Quantitativa Estrutura-Atividade , Algoritmos , Simulação por Computador , Humanos , Nanopartículas Metálicas/efeitos adversos , Nanopartículas Metálicas/classificação , Nanoestruturas/efeitos adversos , Nanoestruturas/classificação , Óxidos/classificação
15.
Int J Nanomedicine ; 16: 2761-2773, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33880022

RESUMO

Purpose: The side effects of radiotherapy induced on healthy tissue limit its use. To overcome this issue and fully exploit the potential of radiotherapy to treat cancers, the first-in-class radioenhancer NBTXR3 (functionalized hafnium oxide nanoparticles) has been designed to amplify the effects of radiotherapy. Patients and Methods: Thanks to its physical mode of action, NBTXR3 has the potential to be used to treat any type of solid tumor. Here we demonstrate that NBTXR3 can be used to treat a wide variety of solid cancers. For this, we evaluated different parameters on a large panel of human cancer models, such as nanoparticle endocytosis, in vitro cell death induction, dispersion, and retention of NBTXR3 in the tumor tissue and tumor growth control. Results: Whatever the model considered, we show that NBTXR3 was internalized by cancer cells and persisted within the tumors throughout radiotherapy treatment. NBTXR3 activated by radiotherapy was also more effective in destroying cancer cells and in controlling tumor growth than radiotherapy alone. Beyond the effects of NBTXR3 as single agent, we show that the antitumor efficacy of cisplatin-based chemoradiotherapy treatment was improved when combined with NBTXR3. Conclusion: These data support that NBTXR3 could be universally used to treat solid cancers when radiotherapy is indicated, opening promising new therapeutic perspectives of treatment for the benefit of many patients.


Assuntos
Antineoplásicos/uso terapêutico , Háfnio/química , Nanopartículas/química , Neoplasias/radioterapia , Óxidos/química , Animais , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Cisplatino/farmacologia , Cisplatino/uso terapêutico , Terapia Combinada , Endocitose/efeitos dos fármacos , Humanos , Camundongos Nus , Nanopartículas/administração & dosagem , Nanopartículas/ultraestrutura , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Distribuição Tecidual/efeitos dos fármacos , Resultado do Tratamento
16.
Photochem Photobiol Sci ; 20(1): 153-160, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33721245

RESUMO

A flower-like nanostructured MnO2 with near-infrared (NIR) light-triggered high photothermal conversion capability of 30% and reactive oxygen species (ROS) generation ability was successfully developed. Different from the reported MnO2 nanomaterials those were used in the nanomedicine field for only relieving tumor hypoxia and/or imaging, the flower-like MnO2 inherently acts as a competent agent for simultaneously enhanced photothermal and photodynamic therapy. A flower-like nanostructured MnO2 with near-infrared (NIR) light triggered high photothermal conversion capability of 30% and reactive oxygen species (ROS) generation ability was successfully developed.


Assuntos
Compostos de Manganês/química , Nanoestruturas/química , Óxidos/química , Sobrevivência Celular/efeitos dos fármacos , Glutationa/química , Células HeLa , Humanos , Peróxido de Hidrogênio/química , Raios Infravermelhos , Compostos de Manganês/metabolismo , Compostos de Manganês/farmacologia , Óxidos/metabolismo , Óxidos/farmacologia , Fototerapia , Espécies Reativas de Oxigênio/metabolismo
17.
ACS Appl Mater Interfaces ; 13(13): 14928-14937, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33759491

RESUMO

In order to achieve safe and high-efficient photodynamic therapy (PDT), it was a powerful strategy of constructing O2-generated nanozyme with intelligent "off/on" modulation and enhancement. Herein, a kind of H2O2-responsive nanozyme was developed for off/on modulation and enhancement of magnetic resonance (MR) imaging and PDT, in which great amounts of gold nanoclusters (AuNCs) were loaded into mesoporous silica to form nanoassembly, and manganese dioxide (MnO2) nanosheets were wrapped as switching shield shell (AuNCs@mSiO2@MnO2). In a neutral physiological environment, stable MnO2 shells eliminated singlet oxygen (1O2) generation to switch off PDT and MR imaging. However, in an acidic tumor microenvironment, the MnO2 shell reacted with H2O2, in which MnO2 degradation switched on MR imaging and PDT, and the generated O2 further enhanced PDT. H2O2-responsive MnO2 degradation brought about excellent MR imaging with a longitudinal relaxation rate of 25.31 mM-1 s-1, and simultaneously sufficient O2 generation guaranteed a 74% high 1O2 yield. Under the irradiation of a 635 nm laser, the viability of MDA-MB-435 cells was reduced to 4%, and the tumors completely disappeared, demonstrating strong PDT performance. Therefore, H2O2-responsive AuNCs@mSiO2@MnO2 nanozyme showed excellent off/on modulation and enhancement of MR imaging and PDT and was a promising intelligent nanoprobe for safe and high-efficiency theranostics.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/tratamento farmacológico , Ouro/uso terapêutico , Compostos de Manganês/uso terapêutico , Nanopartículas/uso terapêutico , Óxidos/uso terapêutico , Fármacos Fotossensibilizantes/uso terapêutico , Animais , Linhagem Celular Tumoral , Feminino , Ouro/química , Humanos , Peróxido de Hidrogênio/metabolismo , Imageamento por Ressonância Magnética , Compostos de Manganês/química , Camundongos , Camundongos Nus , Nanopartículas/química , Óxidos/química , Fotoquimioterapia , Fármacos Fotossensibilizantes/química
18.
ACS Appl Mater Interfaces ; 13(13): 15881-15889, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33779139

RESUMO

Dye sensitization achieving photoelectrochemical (PEC) signal amplification for ultrasensitive bioanalysis has undergone a major breakthrough. In this proposal, an innovative PEC sensing platform is developed by combining Z-scheme WO3@SnS2 photoactive materials and a G-wire superstructure as well as a dye sensitization enhancement strategy. The newly synthesized WO3@SnS2 heterojunction with outstanding PEC performance is employed as a photoelectrode matrix. Due to the formation of the Z-scheme heterojunction between WO3 and SnS2, the migration dynamics of the photogenerated carrier is evidently augmented. To improve sensitivity, the target excision-driven dual-cycle signal amplification strategy is introduced to output exponential c-myc fragments. Crystal violet is then conjugated into the G-quadruplex to amplify the PEC signal, where crystal violet generates excited electrons by capturing visible light and rapidly injects electrons into the conduction band of SnS2, suppressing the recombination of the photo-induced carrier. Moreover, the G-wire superstructure acts as a universal amplification pathway, ensuring adequate crystal violet loads. Specifically, the biosensor for uracil-DNA glycosylase quantification displays a wide detection range (0.0005-1.0 U/mL) and a lower detection limit (0.00025 U/mL). Furthermore, the Z-scheme electron migration mechanism and the crystal violet sensitization effect are discussed in detail. The construction of the PEC sensor provides a new consideration for signal amplification and material design.


Assuntos
Corantes/química , Violeta Genciana/química , Nanoestruturas/química , Óxidos/química , Sulfetos/química , Compostos de Estanho/química , Tungstênio/química , Uracila-DNA Glicosidase/análise , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Ensaios Enzimáticos/métodos , Células HeLa , Humanos
19.
Food Chem ; 352: 129368, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-33667921

RESUMO

A high-performance voltammetric methodology was developed to achieve ultra-sensitive detection of riboflavin, employing an electrode modified by graphene oxide-covered hollow MnO2 spheres nanocomposite with high catalytic activity, large surface area, and hierarchical layered structure. Under the optimal conditions, the current responses of the oxidation peak located at -0.39 V showed a good linear relationship versus the concentration of riboflavin in the range of 1.0 nM-4.0 µM in acetate buffer (pH 5.4). The limit of detection was determined as 0.26 nM. Moreover, the proposed electrode exhibited high reproducibility (relative standard deviation of 1.7%, n = 10) and excellent stability (97.6% sensitivity within two months), which has been successfully applied to the quantification of riboflavin in complicated food matrices, with results in good accordance with those obtained by chromatography as a reference method, indicating it is an effective sensing platform for ultra-sensitive determination of riboflavin in practical applications.


Assuntos
Eletroquímica/instrumentação , Grafite/química , Compostos de Manganês/química , Óxidos/química , Riboflavina/análise , Catálise , Eletrodos , Análise de Alimentos , Limite de Detecção , Oxirredução , Reprodutibilidade dos Testes
20.
Molecules ; 26(4)2021 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-33670175

RESUMO

A range of solution-processed organic and hybrid organic-inorganic solar cells, such as dye-sensitized and bulk heterojunction organic solar cells have been intensely developed recently. TiO2 is widely employed as electron transporting material in nanostructured TiO2 perovskite-sensitized solar cells and semiconductor in dye-sensitized solar cells. Understanding the optical and electronic mechanisms that govern charge separation, transport and recombination in these devices will enhance their current conversion efficiencies under illumination to sunlight. In this work, density functional theory with Perdew-Burke Ernzerhof (PBE) functional approach was used to explore the optical and electronic properties of three modeled TiO2 brookite clusters, (TiO2)n=5,8,68. The simulated optical absorption spectra for (TiO2)5 and (TiO2)8 clusters show excitation around 200-400 nm, with (TiO2)8 cluster showing higher absorbance than the corresponding (TiO2)5 cluster. The density of states and the projected density of states of the clusters were computed using Grid-base Projector Augmented Wave (GPAW) and PBE exchange correlation functional in a bid to further understand their electronic structure. The density of states spectra reveal surface valence and conduction bands separated by a band gap of 1.10, 2.31, and 1.37 eV for (TiO2)5, (TiO2)8, and (TiO2)68 clusters, respectively. Adsorption of croconate dyes onto the cluster shifted the absorption peaks to higher wavelengths.


Assuntos
Teoria da Densidade Funcional , Nanoestruturas/química , Energia Solar , Titânio/química , Adsorção , Compostos de Cálcio/química , Fontes de Energia Elétrica , Eletrônica , Elétrons , Óptica e Fotônica/tendências , Óxidos/química , Luz Solar
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