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1.
Braz Oral Res ; 33(suppl 1): e065, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31576949

RESUMO

Additive manufacturing (AM) is an emerging process for biomaterials and medical devices. Direct Laser Metal Sintering (DLMS) is an AM technique used to fabricate Ti-6Al-4V implant materials with enhanced surface-related properties compared with wrought samples; thus, this technique could influence microbial adsorption and colonization. Therefore, this in vitro study was conducted to evaluate the impact of different implant production processes on microbial adhesion of periodontal pathogens. Titanium discs produced using two different processes-conventional and AM-were divided into three groups: conventional titanium discs with machined surface (G1), AM titanium discs with chemical treatment (G2) and AM titanium discs without chemical treatment (G3). Subgingival biofilm composed of 32 species was formed on the titanium discs, and positioned vertically in 96-well plates, for 7 days. The proportions of microbial complexes and the microbial profiles were analyzed using a DNA-DNA hybridization technique, and data were evaluated using Kruskal-Wallis and Dunnett tests (p < 0.05). Lower proportions of the red complex species were observed in the biofilm formed in G2 compared with that in G1 (p < 0.05). Moreover, the proportions of the microbial complexes were similar between G2 and G3 (p > 0.05). Compared with G1, G2 showed reduced levels of Porphyromonas gingvalis , Actinomyces gerencseriae, and Streptococcus intermedius , and increased levels of Parvimonas micra , Actinomyces odontolyticus, and Eikenella corrodens (p < 0.05). The microbial profile of G3 did not differ from G1 and G2 (p > 0.05). The results of this in vitro study showed that titanium discs produced via AM could alter the microbial profile of the biofilm formed around them. Further clinical studies should be conducted to confirm these findings.


Assuntos
Biofilmes/crescimento & desenvolvimento , Titânio/química , Titânio/farmacologia , Análise de Variância , Bactérias/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Sondas de DNA , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Espectroscopia Fotoeletrônica , Valores de Referência , Reprodutibilidade dos Testes , Estatísticas não Paramétricas , Propriedades de Superfície , Fatores de Tempo
2.
Int J Nanomedicine ; 14: 5785-5797, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31440047

RESUMO

Introduction: The targeted delivery of anti-cancer drugs to tumor tissue has been recognized as a promising strategy to increase their therapeutic efficacy and reduce side effects. Mesoporous silica-coated superparamagnetic Fe3O4 nanoparticles (NH2-MSNs), a kind of nanocarrier, can passively enter tumor tissues to enhance the permeability and retention of drugs. However, NH2-MSNs do not specifically bind to cancer cells. This drawback encouraged us to develop a more efficient nanocarrier for cancer therapy. Methods: Herein, we describe the development of an effective nanocarrier based on NH2-MSNs, which were modified with hyaluronic acid on their surface (HA-MSNs) and loaded with doxorubicin (DOX). We have successfully fabricated uniform spherical HA-MSNs nanocarriers. The targeting ability of this delivery system was evaluated through specific uptake by cells and IVIS imaging. Results: DOX-HA-MSNs nanocarriers displayed more dramatic cytotoxic activity against 4T1 breast cancer cells compared to GES-1 gastric mucosa cells. In vivo results revealed that once DOX-HA-MSNs nanocarriers are exposed to an external magnetic field, they could be rapidly attracted to the magnet and effectively cross the cytoplasmic membrane via CD44 receptor-mediated transcytosis. This allows them to access the cancer cell cytoplasm and release DOX based on changes in the physiological environment. Both in vitro and in vivo results demonstrated that the HA-MSNs nanocarriers provided better therapeutic efficacy. Conclusion: The HA-MSNs nanocarriers represent an effective new paradigm to treat cancers due to active targeting to the tumor cells. Moreover, the specific uptake by the tumor effectively protects normal tissues to reduce off-target side effects. The reported findings support further investigation of HA-MSNs for cancer therapy.


Assuntos
Dextranos/química , Sistemas de Liberação de Medicamentos , Ácido Hialurônico/química , Nanopartículas de Magnetita/química , Dióxido de Silício/química , Animais , Linhagem Celular Tumoral , Doxorrubicina/administração & dosagem , Doxorrubicina/farmacologia , Humanos , Nanopartículas de Magnetita/ultraestrutura , Camundongos , Nanopartículas/administração & dosagem , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Espectroscopia Fotoeletrônica , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier , Ensaios Antitumorais Modelo de Xenoenxerto
3.
Chem Commun (Camb) ; 55(70): 10444-10447, 2019 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-31410430

RESUMO

A new series of 2D catalytic materials whose inorganic surfaces are fully covered with pre-designed "promoter" groups are reported. One of them showed excellent biomimetic catalytic activity and provided the lowest detection limit to glucose among the reported 2D materials and their composite materials.


Assuntos
Biomimética , Calcogênios/química , Metais/química , Catálise , Limite de Detecção , Microscopia de Força Atômica , Microscopia Eletrônica de Transmissão , Espectroscopia Fotoeletrônica , Difração de Pó
4.
Ecotoxicol Environ Saf ; 182: 109396, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31276888

RESUMO

We report herein the sonochemical synthesis of a lanthanum dioxide carbonate (La2O2CO3) and zinc ferrite (ZnFe2O4)-loaded reduced graphene oxide (LZF-rGO) nanoheterostructure for ultrasound (US)-assisted degradation of methyl orange (MO) from water. The MO was chosen as a model organic dye due to its toxicological and biodegradable-resistant properties. The LZF-rGO catalyst was characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The results of characterizations confirmed successful synthesis of sonocatalyst. Among different removal systems, US/LZF-rGO displayed outstanding sonodegradation performance for degradation of MO. The maximum removal efficiency of 75.9% was achieved using 0.2 g/L sonocatalyst, 20 mg/L MO, and 0.71 W/cm2 US power intensity for 65 min. MO can be partially adsorbed on LZF-rGO but mostly sonodegraded by reactive radical species. The reaction conditions were optimized by investigating the effect of key operating parameters, including the sonocatalyst dosage, initial MO concentration, US power intensity, presence of inorganic salts, and use of an enhancer, on the decolorization of MO. The degradation intermediates produced from MO during the sonocatalytic process were identified by UPLC®/MS-MS, and possible mechanism and pathway for the degradation of MO in the US/LZF-rGO system were also proposed. Reusability experiments with this sonocatalyst revealed a less than 10% drop in the degradation efficiency after four adsorption-desorption cycles.


Assuntos
Corantes/química , Grafite/química , Lantânio/química , Nanoestruturas/química , Poluentes Químicos da Água/química , Carbonatos , Catálise , Compostos Férricos , Magnetismo , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Modelos Químicos , Óxidos/química , Espectroscopia Fotoeletrônica , Água , Difração de Raios X , Zinco , Compostos de Zinco , Óxido de Zinco/química
5.
World J Microbiol Biotechnol ; 35(8): 121, 2019 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-31332590

RESUMO

The economics of bioflocculant production is coupled with the use of a low-cost substrate at appropriate culture conditions. The use of a waste substrate for this purpose offers an additional treatment measure to mitigate environmental pollution. We investigated the growth of Aspergillus flavus and its bioflocculant yield using chicken viscera hydrolysate as the sole media. The effects of culture conditions including time, pH, shaker speed, temperature and inoculum size on bioflocculant production were all investigated and optimised through response surface method based on the central component design (CCD) package of Design Expert. Next, the purified bioflocculant was physically and chemically characterised. Under optimised culture conditions (incubation time 72 h, pH 7, shaker speed 150 rpm, temperature 35 °C and inoculum 4%), 6.75 g/L yield of crude bioflocculant was recorded. The bioflocculant activity was mostly distributed in the cell-free supernatant with optimum efficiency of 91.8% at a dose of 4 mL/100 mL Kaolin suspension. The purified bioflocculant was a glycoprotein consisting of 23.46% protein and 74.5% sugar, including 46% neutral sugar and 2.01% uronic acid. The X-ray photoelectron spectroscopy fundamental analysis of the purified bioflocculant indicated that the mass proportion of C, O and N, were 63.46%, 27.87% and 8.86%, respectively. The bioflocculant is mainly composed of carbonyl, amino, hydroxyl, and amide functional groups. This study for the first time indicates a high potential of bioflocculant yield from chicken viscera at the appropriate culture conditions.


Assuntos
Aspergillus flavus/metabolismo , Meios de Cultura/química , Animais , Galinhas , Glicoproteínas/metabolismo , Concentração de Íons de Hidrogênio , Microscopia Eletrônica de Varredura , Espectroscopia Fotoeletrônica , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura Ambiente , Vísceras
6.
Int J Nanomedicine ; 14: 4833-4847, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31308661

RESUMO

Background: The use of functionalized graphene oxide (fGO) has led to a new trend in the sensor field, owing to its high sensitivity with regards to sensing characteristics and easy synthesis procedures. Methods: In this study, we developed an ultra-sensitive carboxyl-graphene oxide (carboxyl-GO)-based surface plasmon resonance (SPR) aptasensor using peptides to detect human chorionic gonadotropin (hCG) in clinical serum samples. The carboxyl-GO based SPR aptasensor provided high affinity and stronger binding of peptides, which are great importance to allow for a non-immunological label-free mechanism. Also, it allows the detection of low concentrations of hCG, which are in turn considered to be important clinical parameters to diagnose ectopic pregnancies and paraneoplastic syndromes. Results: The high selectivity of the carboxyl-GO-based SPR aptasensor for hCG recombinant protein was verified by the addition of the interfering proteins bovine serum albumin (BSA) and human serum albumin (HSA), which did not affect the sensitivity of the sensor. The carboxyl-GO-based chip can enhance the assay efficacy of interactions between peptides and had a high affinity binding for a ka of 17×106 M-1S-1. The limit of detection for hCG in clinical serum samples was 1.15 pg/mL. Conclusion: The results of this study demonstrated that the carboxyl-GO-based SPR aptasensor had excellent sensitivity, affinity and selectivity, and thus the potential to be used as disease-related biomarker assay to allow for an early diagnosis, and possibly a new area in the field of biochemical sensing technology.


Assuntos
Técnicas Biossensoriais/instrumentação , Gonadotropina Coriônica/sangue , Grafite/química , Ressonância de Plasmônio de Superfície/instrumentação , Animais , Bovinos , Eletroquímica , Humanos , Peptídeos/química , Espectroscopia Fotoeletrônica , Soroalbumina Bovina/química
7.
Int J Nanomedicine ; 14: 2693-2703, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31354260

RESUMO

Background: Silver, incorporation with natural or synthetic polymers, has been used as an effective antibacterial agent since decades. Silver has potential applications in healthcare especially in nanoparticles form but silver sulfadiazine (AgSD) is the most efficient antibacterial agent especially for burn wound dressings. Method: In this report, mechanical, structural, and antibacterial properties of PAN nanofibers incorporation with silver sulfadiazine are mainly focused. AgSD was loaded for the first time on electrospinning as well as self-synthesized AgSD on PAN nanofibers by solution immersion method and then compared the results of both. Results: Occurrence of chemical reaction among the functional groups of AgSD and PAN were analyzed using FTIR, for both types of specimen. Morphological and surface properties of prepared nanofiber mats were characterized by scanning electron microscope, and it resulted in uniform nanofibers without bead formation. Diameter of nanofibers was slightly increased with addition of AgSD by in situ and immersion methods respectively. Nanoparticles distribution was analyzed by transmission electron microscopy. Thermal properties were analyzed by thermo-gravimetric analyzer and it was observed that AgSD decreased thermal stability of PAN which is better from biomedical perspective. X-ray diffraction declared crystalline structure of nanofiber mats. Presence of Ag and S contents in nanofiber mats was analyzed by X-ray photo spectroscopy. Antibacterial properties of nanofiber mats were investigated by disc diffusion method was carried out. E. coli and Bacillus bacteria strain were used as gram-negative and gram-positive respectively. Zone inhibition of the bacteria was used as a tool to determine effectiveness of AgSD released from PAN nanofiber mats. The antibacterial properties of PAN nanofibers impregnated with AgSD were determined with both types of bacteria strains to compare with control one. Conclusion: On the basis of characterization results it is concluded that PAN/AgSD (immersion) nanofiber mats have better structural and antibacterial properties than that of PAN/AgSD (in situ) nanofiber mats. So, from our point of view, self-synthesized AgSD is recommended for further production of nanofiber mats for antibacterial applications.


Assuntos
Resinas Acrílicas/química , Antibacterianos/farmacologia , Nanofibras/química , Sulfadiazina de Prata/farmacologia , Bacillus/efeitos dos fármacos , Módulo de Elasticidade , Escherichia coli/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Nanofibras/ultraestrutura , Espectroscopia Fotoeletrônica , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Estresse Mecânico , Resistência à Tração , Termogravimetria , Difração de Raios X
8.
Environ Sci Pollut Res Int ; 26(23): 23981-23993, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31222649

RESUMO

In order to improve the adsorption efficiency of the adsorbent and solve the problem of separation difficulty, a novel superparamagnetic micro-nano-bio-adsorbent (PDA/Fe3O4/BC) was prepared by in situ self-assembly of polydopamine (PDA). The results of scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared spectrometer (FT-IR), X-ray photoelectron spectrometer (XPS), and vibrating sample magnetometer (VSM) characterization showed that the size of bio-adsorbent was about 200 nm. PDA and Fe3O4 modifications increased the specific surface area of adsorbent, changed the surface functional group of biochar (BC), and made the adsorbent have super-high magnetization (294.76 emu g-1). PDA/Fe3O4/BC was applied to treat Cr wastewater. The results show that the adsorption of Cr by PDA/Fe3O4/BC includes single-layer and multilayer adsorption. The adsorption follows the pseudo-second-order kinetic model. The adsorption is spontaneous and endothermic, and its maximum adsorption capacity and activation energy are 25.25 mg g-1 at 318 K and 23.108 kJ mol-1, respectively. After adsorption treatment, PDA/Fe3O4/BC still possesses high magnetization (233.04 emu g-1). PDA/Fe3O4/BC can treat actual electroplating wastewater with Cr(VI) concentration from 20 mg L-1 to less than 0.2 mg L-1, which met the PRC discharge standard (GB/21900-2008) of electroplating pollutants. Graphical abstract.


Assuntos
Galvanoplastia , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Poluentes Químicos da Água/química , Adsorção , Carvão Vegetal , Cromo , Concentração de Íons de Hidrogênio , Indóis , Íons , Cinética , Nanopartículas de Magnetita/química , Espectroscopia Fotoeletrônica , Polímeros , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/análise , Difração de Raios X
9.
Environ Pollut ; 251: 975-983, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31234265

RESUMO

Efficient containment and capture of uranium (U(VI)) from aqueous solution is an essential component to ensure socially and environmentally sustainable development. Herein, the three-dimensional graphene/titanium dioxide composite (3D GA/TiO2) was synthesized and applied as an effective adsorbent to remove U(VI) from wastewater as a function of contact time, temperature, pH and ion strength. The 3D GA/TiO2 material was characterized by X-ray diffraction, Raman spectroscopy, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The batch experiments results indicated that the adsorption of U(VI) on materials were fitted with the pseudo-second order kinetics and Langmuir models. More specifically, 3D GA/TiO2 (441.3 mg/g) was observed to outperform the GO (280.0 mg/g), rGO (140.9 mg/g) and TiO2 (98.5 mg/g) at pH 5.0, which was attributable to the excellent cooperative effects. Furthermore, XPS analyses and DFT calculations confirmed the formation of surface complexes between oxygen-containing group and U(VI) with the U-O bonds length of 2.348 Š(U-O1) and 2.638 Š(U-O2). Meanwhile, the adsorption energy was calculated to be 1.60 eV, which showed a very strong chemisorption during the interaction process. It is believed that the 3D GA/TiO2 revealed good removal performance for uranyl ions, which showed a great potential application to control the nuclear industrial pollution.


Assuntos
Recuperação e Remediação Ambiental/métodos , Grafite/química , Titânio/química , Urânio/análise , Águas Residuárias/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção , Teoria da Densidade Funcional , Concentração Osmolar , Espectroscopia Fotoeletrônica , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
10.
Anal Bioanal Chem ; 411(17): 3801-3810, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31172237

RESUMO

The convenience of colorimetric sensors is useful for practical applications. In this work, we constructed a novel colorimetric sensor with magnetic separation ability that can be operated in nearly neutral conditions and achieve one-step detection of metabolites. Magnetic Cu doped Fe3O4@FeOOH magnetic nanocomposite (Cu/Fe3O4@FeOOH) with an oxygen vacancy was prepared by a one-step self-assembly hydrothermal method, and fully characterized by different methods. The oxygen vacancy generated by the incorporation of Cu2+ cations into the Fe3O4@FeOOH structure was confirmed to be a vital reactive site for enhancing the catalytic activity, which opens up a new way of designing highly efficient enzyme mimics. Benefiting from its inherent horseradish-peroxidase-like activity, a simple and selective enzyme-based colorimetric sensor was developed for one-step detection of H2O2 and cholesterol, and 3,3',5,5'-tetramethylbenzidine was catalyzed by H2O2 to generate a colored product of oxidized 3,3',5,5'-tetramethylbenzidine for signaling. H2O2 and cholesterol can be linearly detected in the same range from 0.01 to 0.4 mmol L-1 with detection limits of 0.0075 mmol L-1 and 0.0082 mmol L-1, respectively. The proposed colorimetric sensor has satisfactory reusability, accuracy, and practicability in human serum samples, indicating its potential application for the detection of different metabolites in the fields of life science and analytical science. Graphical abstract.


Assuntos
Técnicas Biossensoriais/métodos , Colorimetria/métodos , Cobre/química , Óxido Ferroso-Férrico/química , Peroxidase do Rábano Silvestre/química , Concentração de Íons de Hidrogênio , Magnetismo , Nanopartículas Metálicas/química , Benzidinas/química , Colesterol/sangue , Espectroscopia de Ressonância de Spin Eletrônica , Peróxido de Hidrogênio/análise , Microscopia Eletrônica de Transmissão , Oxirredução , Espectroscopia Fotoeletrônica , Reprodutibilidade dos Testes , Análise Espectral Raman , Difração de Raios X
11.
Anal Bioanal Chem ; 411(20): 5149-5157, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31250067

RESUMO

A mandatory step in any sensor fabrication is the introduction of analyte-specific recognition elements to the transducer surface. In this study, the possibility to anchor ß-cyclodextrin-modified dopamine to a reduced graphene oxide based electrochemical transducer for the sensitive and selective sensing of folic acid is demonstrated. The sensor displays good electrocatalytic activity toward the oxidation of folic acid. The strong affinity of the surface-confined ß-cyclodextrin for folic acid, together with favorable electron transfer characteristics, resulted in a sensor with a detection limit of 1 nM for folic acid and a linear response up to 10 µM. Testing of the sensor on serum samples from healthy individuals and patients diagnosed with folic acid deficiency validated the sensing capability. Graphical abstract.


Assuntos
Ciclodextrinas/química , Dopamina/química , Eletrodos , Ácido Fólico/sangue , Grafite/química , Técnicas Eletroquímicas/métodos , Humanos , Limite de Detecção , Oxirredução , Espectroscopia Fotoeletrônica
12.
Int J Nanomedicine ; 14: 3517-3524, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31190808

RESUMO

Background: Liver plays a vital role in the elimination of xenobiotics that can induce hepatotoxicity in living organisms.Silver nanoparticles have evolved recently as an alternative in various industries and are used for their biomedical applications.Rhizophora apiculata is a least studied mangrove-based plant that has been used in the traditional medicine of Southeast Asia for its healing properties. It is a well-known fact that the generation of free radicals has been associated with oxidative stress.  Methods: Hence, in this study we used carbon tetrachloride as a hepatotoxin to induce liver damage. The protective effects of silver nanoparticles synthesized using Rhizophora apiculata on hepatotoxin-induced liver damage in experimental mice were assessed.  Results: The results of the assessment indicate that silver nanoparticles were effective in protecting the liver from damages induced by carbon tetrachloride.  Conclusion: Among existing literature, this is the first ever approach for hepatoprotective effect of nanoparticles derived using plant extract from mangrove ecosystem.


Assuntos
Nanopartículas Metálicas/química , Extratos Vegetais/farmacologia , Folhas de Planta/química , Substâncias Protetoras/farmacologia , Rhizophoraceae/química , Prata/farmacologia , Animais , Tetracloreto de Carbono , Fígado/efeitos dos fármacos , Fígado/patologia , Masculino , Nanopartículas Metálicas/ultraestrutura , Camundongos , Espectroscopia Fotoeletrônica , Espectrometria por Raios X
13.
J Environ Sci (China) ; 83: 183-194, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31221381

RESUMO

The photocatalytic activity of Fe-doped TiO2 nanoparticles is significantly increased by an acid-treatment process. The photocatalyst nanoparticles were prepared using sol-gel method with 0.5 mol% ratio of Fe:Ti in acidic pH of 3. The nanoparticles were structurally characterized by means of X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and diffuse reflectance spectroscopy (DRS). It was observed that the photocatalytic activity suffered from an iron oxide contaminating layer deposited on the surface of the nanoparticles. This contamination layer was removed using an HCl acid-treatment process. The photocatalytic activity using 500 mg/L of Fe0.5-TiO2 in a 10 mg/L of phenol solution increased significantly from 33% to 57% (about 73% increase in the performance), within 90 min of reaction time under visible light irradiation. This significant improvement was achieved by removing the iron oxide contamination layer from the surface of the nanoparticles and adjusting pH to mild acidic and basic pHs.


Assuntos
Modelos Químicos , Fenol/química , Processos Fotoquímicos , Catálise , Luz , Fenóis , Espectroscopia Fotoeletrônica , Espectrometria por Raios X , Titânio/química , Difração de Raios X
14.
Chemistry ; 25(43): 10188-10196, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31192495

RESUMO

The fabrication of carbon dots and their doped forms by top-down chemical cleavage has attracted considerable attention in the efforts to meet the increasing demands for optoelectronic applications ranging from biosensing to electro- and photocatalysis. However, due to strong quantum confinement effects, the size decrease often leads to an increase in the band gap, even in the emission of deep-ultraviolet (DUV) light, which greatly limits their applications. Here, we report a facile hot-tailoring strategy for fabricating carbon nitride nanodots (CNDs) with redshifted intrinsic photoluminescent (PL) emission, compared with the pristine bulk precursor. It has been found that the different leaving abilities of the C,N-containing groups during the pyrolysis stage and the chemical passivation during the liquid-collection stage played vital roles. Due to the redshifted photoluminescence and other attractive features, the as-obtained CNDs were successfully applied in visual double text encryption with higher security and also in bioimaging with photostability superior to traditional dyes. This work highlights the great potential of the hot-tailoring method in modulating carbon-based nanostructures and offsetting band-gap widening as the size decreases.


Assuntos
Nitrilos/química , Pontos Quânticos/química , Sobrevivência Celular/efeitos dos fármacos , Humanos , Células MCF-7 , Microscopia Confocal , Espectroscopia Fotoeletrônica , Pirólise , Pontos Quânticos/toxicidade , Espectrometria de Fluorescência , Raios Ultravioleta
15.
Food Chem ; 293: 387-395, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31151626

RESUMO

The endogenous carbon quantum dots (CQDs) produced during food processing have potential uncertainty to human health. The objective of this study was to investigate the formation, biodistribution and cytotoxicity of CQDs in roasted Atlantic salmon (Salmo salar Linnaeus). The X-ray photoelectron spectroscopy (XPS) analysis showed that the CQDs were mainly composed of carbon, oxygen and nitrogen. The morphology, functional groups and optical properties were highly dependent on the roasting time. In vivo experiments in mice demonstrated that the CQDs distributed in the digestive tract, kidney, liver, and even brain, which indicated that they could cross the blood-brain barrier. The cell imaging results indicated that the CQDs could readily gain access to the normal rat kidney (NRK) cells, and caused autophagosome formation. The proportion of live cells decreased to 34.62% at 6 mg mL-1 of CQDs, and the energy generation route was changed from aerobic to glycolytic metabolism.


Assuntos
Pontos Quânticos/química , Pontos Quânticos/toxicidade , Salmo salar , Animais , Apoptose/efeitos dos fármacos , Autofagossomos/efeitos dos fármacos , Autofagossomos/metabolismo , Barreira Hematoencefálica/efeitos dos fármacos , Carbono/análise , Ciclo Celular/efeitos dos fármacos , Linhagem Celular , Culinária , Masculino , Camundongos Endogâmicos BALB C , Nitrogênio/análise , Oxigênio/análise , Espectroscopia Fotoeletrônica , Pontos Quânticos/metabolismo , Ratos , Distribuição Tecidual
16.
Dent Mater J ; 38(3): 496-504, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31068553

RESUMO

To elucidate the mechanism of adhesion of soft and hard tissues to yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP), Y-TZP and titanium disks were immersed in ultrapure water and in Hanks' solution, and the changes in the surface compositions and chemical states were characterized using X-ray photoelectron spectroscopy. After immersion in ultrapure water for 60 days, the concentration of hydroxyl groups on the Y-TZP surface increased. In addition, only phosphate ions were incorporated into the surface during immersion in Hanks' solution, while other ions did not react. On the other hand, the surface of Ti was also hydrated in ultrapure water; however, calcium phosphate formed on it during immersion in Hanks' solution. Therefore, the reactivity of Y-TZP with electrolytes was lower than that of Ti. We conclude that the formation of the phosphate on the Y-TZP surface in physiological conditions possibly enhances the adhesion of soft and hard tissues to Y-TZP.


Assuntos
Água , Ítrio , Teste de Materiais , Espectroscopia Fotoeletrônica , Propriedades de Superfície , Zircônio
17.
Molecules ; 24(9)2019 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-31071946

RESUMO

This work incorporates a variety of conjugated donor-acceptor (DA) co-monomers such as 2,6-diaminopurine (DP) into the structure of a polymeric carbon nitride (PCN) backbone using a unique nanostructure co-polymerization strategy and examines its photocatalytic activity performance in the field of photocatalytic CO2 reduction to CO and H2 under visible light irradiation. The as-synthesized samples were successfully analyzed using different characterization methods to explain their electronic and optical properties, crystal phase, microstructure, and their morphology that influenced the performance due to the interactions between the PCN and the DPco-monomer. Based on the density functional theory (DFT) calculation result, pure PCN and CNU-DP15.0 trimers (interpreted as incorporation of the co-monomer at two different positions) were extensively evaluated and exhibited remarkable structural optimization without the inclusion of any symmetry constraints (the non-modified sample derived from urea, named as CNU), and their optical and electronic properties were also manipulated to control occupation of their respective highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). Also, co-polymerization of the donor-acceptor 2,6-diamino-purine co-monomer with PCN influenced the chemical affinities, polarities, and acid-base functions of the PCN, remarkably enhancing the photocatalytic activity for the production of CO and H2 from CO2 by 15.02-fold compared than that of the parental CNU, while also improving the selectivity.


Assuntos
Dióxido de Carbono/química , Elétrons , Luz , Nitrilos/química , Polímeros/química , Adsorção , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Catálise/efeitos da radiação , Eletroquímica , Nitrogênio/química , Oxirredução , Espectroscopia Fotoeletrônica , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
18.
Molecules ; 24(9)2019 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-31072045

RESUMO

A novel sensing system has been designed for the detection of cupric ions. It is based on the quenched fluorescence signal of carbon dots (CDs), which were carbonized from poly(vinylpyrrolidone) (PVP) and L-Cysteine (CYS). Cupric ions interact with the nitrogen and sulfur atoms on surface of the CDs to form an absorbed complex; this results in strong quenching of the fluorescence of the CDs via a fast metal-to-ligand binding affinity. The synthesized water-soluble CDs also exhibited a quantum yield of 7.6%, with favorable photoluminescent properties and good photostability. The fluorescence intensity of the CDs was very stable in high ionic strength (up to 1.0 M NaCl) and over a wide range of pH levels (2.0-12.0). This facile method can therefore develop a sensor that offers reliable, fast, and selective detection of cupric ions with a detection limit down to 0.15 µM and a linear range from 0.5 to 7.0 µM (R2 = 0.980). The CDs were used for cell imaging, observed that they were low toxicity to Tramp C1 cells and exhibited blue and green and red fluorescence under a fluorescence microscope. In summary, the CDs exhibited excellent fluorescence properties, and could be applied to the selective and sensitive detection of cupric ion and multicolor cell imaging.


Assuntos
Carbono/química , Cobre/análise , Imagem Tridimensional/métodos , Sondas Moleculares/síntese química , Pontos Quânticos/química , Animais , Carbono/toxicidade , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Fluorescência , Íons , Camundongos Transgênicos , Sondas Moleculares/química , Espectroscopia Fotoeletrônica , Pontos Quânticos/toxicidade , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/análise
19.
Ultrason Sonochem ; 57: 233-241, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31103278

RESUMO

4-Nitroquinoline N-oxide (4-NQO) is an important tumorigenic organic compound with high adverse effect in the human body. In this study, a novel Bismuth Tungstate nanospheres (Bi2WO6) decorated reduced graphene oxide (Bi2WO6/rGOS) nanocomposite have been designed through a sonochemical method. The as-synthesized Bi2WO6/rGOS was characterized through the HRTEM, FESEM, XPS, EIS and XRD. Furthermore, the nanocomposite modified glassy carbon electrode (GCE) was developed for the determination of 4-NQO. The results showed that the Bi2WO6/rGOS nanocomposite modified electrode exhibit valuable responses and excellent electrocatalytic activity. The fabricated sensor was facilitated the analysis of 4-NQO with a nanomolar detection limit (6.11 nM). Further, the as-synthesized Bi2WO6/rGOS modified electrode has been applied to sensing of 4-NQO in human blood and urine samples with satisfactory recovery.


Assuntos
Eletrodos , Grafite/química , Nanosferas/química , Estresse Oxidativo , Ondas Ultrassônicas , Biomarcadores/metabolismo , Concentração de Íons de Hidrogênio , Limite de Detecção , Espectroscopia Fotoeletrônica , Reprodutibilidade dos Testes , Difração de Raios X
20.
Environ Sci Technol ; 53(11): 6454-6461, 2019 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-31081617

RESUMO

The effect of Cr(VI) and bisphenol A (BPA) on U(VI) photoreduction by C3N4 photocatalyst was demonstrated by the batch experiments, electron spin resonance (ESR), X-ray photoelectron spectroscopy (XPS), X-ray absorption near edge structure (XANES), and extended X-ray absorption fine structure (EXAFS) techniques. The batch experiments manifested that Cr(VI) and BPA enhanced the photocatalytic activity of C3N4 for U(VI) photoreduction, whereas U(VI) photoreduction was significantly diminished with increased pH from 4.0 to 8.0. According to radical scavengers and ESR analysis, U(VI) was photoreduced to U(IV) by photogenerated electrons of conduction band edge, whereas Cr(VI) was reduced to Cr(III) by H2O2. BPA and its products such as organic acid and alcohols can capture photoinduced holes, which resulted in the enhancement of U(VI) photoreduction to U(IV). XPS and XANES analyses demonstrated that U(VI) was gradually photoreduced to U(IV) by C3N4 within irradiation 60 min, whereas U(IV) was reoxidized to U(VI) with increasing irradiation time. EXAFS analysis determined that the dominant interaction mechanisms of U(VI) on C3N4 after irradiation for 240 min were reductive precipitation and inner-sphere surface complexation. This work highlights the synergistic removal of radionuclides, heavy metals, and persistent organic pollutants by C3N4, which is crucial for the design and application of a high-performance photocatalyst in actual environmental cleanup.


Assuntos
Peróxido de Hidrogênio , Compostos Benzidrílicos , Cromo , Espectroscopia de Ressonância de Spin Eletrônica , Fenóis , Espectroscopia Fotoeletrônica
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