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Angew Chem Int Ed Engl ; 59(10): 4043-4050, 2020 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-31919948


Ni,N-doped carbon catalysts have shown promising catalytic performance for CO2 electroreduction (CO2 R) to CO; this activity has often been attributed to the presence of nitrogen-coordinated, single Ni atom active sites. However, experimentally confirming Ni-N bonding and correlating CO2 reduction (CO2 R) activity to these species has remained a fundamental challenge. We synthesized polyacrylonitrile-derived Ni,N-doped carbon electrocatalysts (Ni-PACN) with a range of pyrolysis temperatures and Ni loadings and correlated their electrochemical activity with extensive physiochemical characterization to rigorously address the origin of activity in these materials. We found that the CO2 R to CO partial current density increased with increased Ni content before plateauing at 2 wt % which suggests a dispersed Ni active site. These dispersed active sites were investigated by hard and soft X-ray spectroscopy, which revealed that pyrrolic nitrogen ligands selectively bind Ni atoms in a distorted square-planar geometry that strongly resembles the active sites of molecular metal-porphyrin catalysts.

Egypt J Immunol ; 26(1): 55-67, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31332996


Diabetes Mellitus (D.M.) is a disease with a high and increasing prevalence. The Insulin- producing Cells (IPCs) derived from the Wharton's jelly of human umbilical cord transplantation was thought to be the most promising strategy for treating Diabetes. This study aimed to evaluate IPCs immune modulatory changes occurred after transplanted through two different routes and the effect of these changes on their therapeutic efficiency in relation to transplantation microenvironment. Insulin Producing Cells was induced to differentiate from human Umbilical Cord-Mesenchymal Stem Cells and characterized by morphology under phase contrast inverted microscope and staining of secretory granules by DTZ (diphenylthiocarbonazone) stain, then therapeutic effect was evaluated both in vitro and in vivo through glucose challenge test and hyperglycemia correction in STZ (streptozotocin)- induced diabetic rats. Immune-modulatory changes evaluated by cell- mediated lysis assay and Syber green quantification of immune inflammatory cytokines (IFN- , TGF- ß and IL-10) gene expression by real-time PCR. We observed that in spite of the weak immunogenicity of induced IPCs derived from HUC-MSCs in vitro, but when transplanted in vivo especially through the intra portal vein they could induce an immune response when interact with the disease microenvironment resulting in different degree of inflammatory response. Therefore, the relationship between disease microenvironment and immune alteration should be examined before transplantation therapy.

Diabetes Mellitus Experimental/imunologia , Insulinas , Transplante de Células-Tronco Mesenquimais , Geleia de Wharton/citologia , Animais , Diferenciação Celular , Citocinas/imunologia , Diabetes Mellitus Experimental/terapia , Humanos , Células-Tronco Mesenquimais/citologia , Ratos , Cordão Umbilical/citologia
Future Med Chem ; 10(22): 2577-2588, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30526035


AIM: There is an urgent need to develop alternative antimicrobial agents and, one of which is via the use of nanotechnology. Green synthetic routes are recently being replaced for nanoparticles preparation. Methods results: Silver-curcumin nanoconjugates (Ag-CurNCs) were prepared in an eco-friendly method. The prepared nanomaterials were characterized and the photostability was studied under the influence of UV irradiation. Results showed that, the conjugation between curcumin and silver in the nanoform improve the photostability of curcumin. Cytotoxicity was studied on different skin cell lines, and antibacterial activity was investigated against Escherichia coli. Results revealed the antibacterial activity of the prepared nanoconjugates (Ag-CurNCs) with minimal toxicity to skin cells. CONCLUSION: Silver nanoparticles improve the photostability and antibacterial activity of curcumin, while curcumin helps in preparing biocompatible silver nanoparticles.

Antibacterianos/química , Antibacterianos/farmacologia , Antineoplásicos/química , Antineoplásicos/farmacologia , Curcumina/análogos & derivados , Curcumina/farmacologia , Prata/química , Prata/farmacologia , Antibacterianos/síntese química , Antineoplásicos/síntese química , Linhagem Celular , Linhagem Celular Tumoral , Curcumina/síntese química , Escherichia coli/efeitos dos fármacos , Infecções por Escherichia coli/tratamento farmacológico , Química Verde/métodos , Humanos , Nanopartículas Metálicas/química , Nanoconjugados/química , Neoplasias Cutâneas/tratamento farmacológico
Talanta ; 185: 344-351, 2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-29759210


A strategy for trace-level carbon-based electrochemical sensors is investigated via exploring the interesting properties of BaNb2O6 nanofibers (NFs). Utilizing adsorptive stripping square wave voltammetry (ASSWV), an electrochemical sensing platform was developed based on BaNb2O6 nanofibers-modified carbon paste electrode (CPE) for the sensitive detection of lornoxicam (LOR). Different techniques were used to characterize the fabricated BaNb2O6 perovskite NFs. The obtained data show the feasibility to electro-oxidize LOR and paracetamol (PAR) on the surface of the fabricated sensor. The amount of nanofiber and testing conditions were optimized using response surface methodology and ASSWV technique. The optimized BaNb2O6/CPE sensor exhibits low detection limit of 6.39 × 10-10 mol L-1, even in the presence of the co-formulated drug paracetamol (PAR). The sensor was successfully applied for biological applications.

Anti-Inflamatórios não Esteroides/análise , Compostos de Cálcio/química , Técnicas Eletroquímicas , Nanofibras/química , Óxidos/química , Piroxicam/análogos & derivados , Titânio/química , Carbono/química , Eletrodos , Estrutura Molecular , Tamanho da Partícula , Piroxicam/análise
Sci Rep ; 8(1): 7988, 2018 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-29789633


Rational design of binder-free materials with high cyclic stability and high conductivity is a great need for high performance supercapacitors. We demonstrate a facile one-step synthesis method of binder-free MnO@C nanofibers as electrodes for supercapacitor applications. The topology of the fabricated nanofibers was investigated using FESEM and HRTEM. The X-ray photoelectron spectroscopy (XPS) and the X-ray diffraction (XRD) analyses confirm the formation of the MnO structure. The electrospun MnO@C electrodes achieve high specific capacitance of 578 F/g at 1 A/g with an outstanding cycling performance. The electrodes also show 127% capacity increasing after 3000 cycles. An asymmetric supercapacitor composed of activated carbon as the negative electrode and MnO@C as the positive electrode shows an ultrahigh energy density of 35.5 Wh/kg with a power density of 1000 W/kg. The device shows a superior columbic efficiency, cycle life, and capacity retention.

Asian Pac J Cancer Prev ; 16(14): 6039-46, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26320493


AIMS: To investigate effect of metallic nanoparticles, silver (AgNPs) and gold nanoparticles (AuNPs) as antitumor treatment in vitro against human breast cancer cells (MCF-7) and their associated mechanisms. This could provide new class of engineered nanoparticles with desired physicochemical properties and may present newer approaches for therapeutic modalities to breast cancer in women. MATERIALS AND METHODS: A human breast cancer cell line (MCF-7) was used as a model of cells. Metallic nanoparticles were characterized using UV-visible spectra and transmission electron microscopy (TEM). Cytotoxic effects of metallic nanoparticles on MCF-7 cells were followed by colorimetric SRB cell viability assays, microscopy, and cellular uptake. Nature of cell death was further investigated by DNA analysis and flow cytometry. RESULTS: Treatment of MCF-7 with different concentrations of 5-10nm diameter of AgNPs inhibited cell viability in a dose-dependent manner, with IC50 value of 6.28µM, whereas treatment of MCF-7 with different concentrations of 13-15nm diameter of AuNPs inhibited cell viability in a dose-dependent manner, with IC50 value of 14.48µM. Treatment of cells with a IC50 concentration of AgNPs generated progressive accumulation of cells in the S phase of the cell cycle and prevented entry into the M phase. The treatment of cells with IC50 concentrations of AuNPs similarly generated progressive accumulation of cells in sub-G1 and S phase, and inhibited the entrance of cells into the M phase of the cell cycle. DNA fragmentation, as demonstrated by electrophoresis, indicated induction of apoptosis. CONCLUSIONS: Our engineered silver nanoparticles effectively inhibit the proliferation of human breast carcinoma cell line MCF-7 in vitro at high concentration (1000 µM) through apoptotic mechanisms, and may be a beneficial agent against human carcinoma but further detailed study is still needed.

Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Proliferação de Células/efeitos dos fármacos , Ouro/química , Nanopartículas Metálicas/administração & dosagem , Nanopartículas Metálicas/química , Prata/química , Apoptose/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Feminino , Citometria de Fluxo , Humanos , Técnicas In Vitro , Microscopia Eletrônica de Transmissão , Células Tumorais Cultivadas