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1.
J Photochem Photobiol B ; 197: 111545, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31326847

RESUMO

Proper waste utilization in order to promote value added product is a promising scientific practice in recent era. Inspiring from the recurring trend, we propose a single step oxidative pyrolysis derived fluorescent carbon dots (C-dots) from Allium sativum peel, which is a natural, nontoxic, and waste raw material. Because of its excellent optical properties, and photostability this C-dots have been used in versatile area of applications. Due to its immediate water dispersing character, C-dots reinforced Poly(acrylic acid) (PAA) films revealed improvement in uniaxial stretching behavior and can be used as transparent sunlight conversion film. The nanocomposite film has been tested against rigorous simulated sunlight which proved almost identical sunlight conversion behavior with no photo-bleachable character which is definitely added an extra quality of transparent polymer films. Moreover, the C-dots dispersion has been used as in vitro biomarker for living cells owing to its ease in solubility, biocompatibility, non-cytotoxicity and bright fluorescence even in subcutaneous environment. For this case, adipose derived mesenchymal stem cells (ADMSCs) have been chosen and injected to rabbit ear skin to perform two-photon imaging experiment. The present work opens a new avenue towards the large-scale synthesis of bio-waste based fluorescent C-dots, paving the way for their versatile applications.


Assuntos
Allium/química , Nitrogênio/química , Fotodegradação/efeitos da radiação , Pontos Quânticos/química , Enxofre/química , Luz Solar , Resinas Acrílicas/química , Tecido Adiposo/citologia , Allium/metabolismo , Animais , Materiais Biocompatíveis/química , Carbono/química , Sobrevivência Celular/efeitos dos fármacos , Frutas/química , Frutas/metabolismo , Química Verde , Masculino , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Microscopia de Fluorescência , Pontos Quânticos/toxicidade , Coelhos , Pele/efeitos dos fármacos , Pele/patologia , Solubilidade
2.
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
3.
Ecotoxicol Environ Saf ; 181: 336-344, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31202934

RESUMO

The present study focused on the bioaccumulation and cytotoxicities of Cd2+, CdSe quantum dots (QDs) and CdSe/ZnS QDs in Escherichia coli (E. coli, represents prokaryotic system) and Phanerochaete chrysosporium (P. chrysosporium, represents eukaryotic system), respectively. Two types of QDs were characterized by transmission electron microscopy (TEM) and dynamic light scattering. The inductively coupled plasma optical emission spectrometer results showed that the bioaccumulation amounts of CdSe QDs by E. coli and P. chrysosporium were larger than those of CdSe/ZnS QDs due to the smaller particle size and less negative surface charges of CdSe QDs. Confocal microscopy and TEM results showed that there was an interaction between QDs and cells, and QDs have entered into the cells eventually, leading to the change of cell morphology. Plasma membrane fluidities and membrane H+-ATPase activities of E. coli and P. chrysosporium decreased gradually with the increasing concentrations of Cd2+, CdSe and CdSe/ZnS QDs. Results of the cell viabilities and intracellular reactive oxygen species levels indicated that the induced cytotoxicities were decreased as follows: CdSe QDs > CdSe/ZnS QDs > Cd2+. These findings suggested that the cytotoxicity of QDs was not only attributed to their heavy metal components, but also related to their nanosize effects which could induce particle-specific toxicity. The above results offer valuable information for exploring the cytotoxicity mechanism of QDs in prokaryote and eukaryote.


Assuntos
Compostos de Cádmio/toxicidade , Cádmio/toxicidade , Pontos Quânticos/toxicidade , Compostos de Selênio/toxicidade , Sulfetos/toxicidade , Compostos de Zinco/toxicidade , Citotoxinas/metabolismo , Citotoxinas/toxicidade , Escherichia coli/efeitos dos fármacos , Escherichia coli/metabolismo , Escherichia coli/ultraestrutura , Íons , Fluidez de Membrana/efeitos dos fármacos , Viabilidade Microbiana/efeitos dos fármacos , Phanerochaete/efeitos dos fármacos , Phanerochaete/ultraestrutura , Pontos Quânticos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Sulfetos/metabolismo , Compostos de Zinco/metabolismo
4.
Ecotoxicol Environ Saf ; 181: 388-394, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31212187

RESUMO

With the wider application of cadmium-containing quantum dots (Cd-QDs) in biomedical fields, it is easier for people to be exposed. Studies have suggested that Cd-QDs could release cadmium ion and induce oxidative effects due to the disruption of redox equilibrium. Antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD), play an important role in organisms to resist the negative impact of exogenous substances. Molecular mechanisms of antioxidant enzymes with Cd-QDs remain unclear, however. In this study, structural and functional changes of CAT and SOD have been investigated under low dose Cd-QDs exposure. Cell viability, malondialdehyde (MDA) level, CAT and SOD activities were influenced by Cd-QDs in hepatocytes of mice. To further investigate the responses of CAT and SOD to Cd-QDs, multiple spectroscopic, calorimetric and activity measurements were carried out. Similar interaction patterns were observed that result in interaction force, structural and functional changes: Cd-QDs combine with CAT and SOD through hydrophobic forces; Intrinsic fluorescence of proteins was statically quenched by Cd-QDs and new complexes were formed; Also, the skeleton and secondary structure (with α-helix decrease) of CAT and SOD was influenced. Taken together, we suggest that Cd-QDs chosen in this study induce oxidative stress effects to hepatocytes but have not caused serious oxidative stress damage at concentrations below 10 µg/mL. MPA-CdSe/ZnS QDs caused the lowest level of oxidative stress which is associated with the induction of antioxidant proteins. This paper presents responses of CAT and SOD to low-dose Cd-QDs, and provides a reference for evaluating health damages caused by Cd-QDs.


Assuntos
Cádmio/toxicidade , Catalase/metabolismo , Estresse Oxidativo , Pontos Quânticos/toxicidade , Superóxido Dismutase/metabolismo , Animais , Antioxidantes/metabolismo , Hepatócitos/efeitos dos fármacos , Hepatócitos/enzimologia , Malondialdeído/metabolismo , Camundongos
5.
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
6.
Talanta ; 201: 309-316, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31122428

RESUMO

Two different colors of water-soluble core-shell quantum dots CdTe/CdS (green and orange red) have been synthesized and characterized in this paper. The formation of core-shell quantum dots not only improves the fluorescence quantum yield, but also reduces the biological toxicity of quantum dots, and improves the fluorescence lifetime. Two novel fluorescent bioprobes, CdTe/CdS (λem = 545 nm)-5-Fu and Bio-CdTe/CdS (λem = 600 nm)-TAM, have been synthesized via the interaction of these two core-shell quantum dots with anticancer drugs (5-Fu) and P-gp inhibitors (TAM), respectively. These two fluorescent probes have been simultaneously used in fluorescence imaging of human breast cancer cells MDA-MB-231/MDR. It can be observed that under the action of P-gp inhibitors distributed on the cell membrane, anticancer drugs can be retained in cancer cells. According to the color of quantum dots on the probe, the visualization results of the action of anticancer drugs and P-gp inhibitors can be obtained. This study shows that to prepare functional bioprobes using core-shell quantum dots CdTe/CdS has great potential in the field of biomedical research such as anticancer drugs.


Assuntos
Antineoplásicos/farmacologia , Resistência a Múltiplos Medicamentos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Corantes Fluorescentes/química , Pontos Quânticos/química , Subfamília B de Transportador de Cassetes de Ligação de ATP/antagonistas & inibidores , Cádmio/química , Cádmio/toxicidade , Compostos de Cádmio/química , Compostos de Cádmio/toxicidade , Linhagem Celular Tumoral , Fluorescência , Corantes Fluorescentes/toxicidade , Fluoruracila/farmacologia , Humanos , Pontos Quânticos/toxicidade , Solubilidade , Espectrometria de Fluorescência/métodos , Sulfetos/química , Sulfetos/toxicidade , Tamoxifeno/farmacologia , Telúrio/química , Telúrio/toxicidade , Água/química
7.
Talanta ; 201: 388-396, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31122439

RESUMO

Ascorbic acid (AA) is an essential vitamin and plays an irreplaceable role in humans' daily life. Therefore, it is of profound significance to develop effective strategies for AA sensing. Herein, a novel bi-functional sensing strategy was developed by using carbon dots (CDs) and MnO2 nanosheet as the fluorometric/magnetic signal source. When AA was absence, the fluorescence of CDs was quenched by MnO2 nanosheet due to the inner filter effect. Neither the fluorescence nor magnetic signal of the nanoprobe can be detected. In the presence of AA, a redox reaction occurred between MnO2 nanosheet and AA resulting in the generation of magnetic resonance imaging (MRI) response Mn2+ and decomposing of MnO2 nanosheet structure, thus leading to the recovery of CDs fluorescence. The detection limit of the AA was determined to be 2.89 µM with a linear range of 0-80 µM in fluorescence mode, and detection limit of 0.776 µM with a linear range of 0-80 µM in MRI mode when used transverse relaxation rate as signal. Furthermore, the developed fluorometric/magnetic bi-functional nanoprobe showed good biocompatibility, high response rate, high selectivity towards AA and could be used to analyses AA in real samples. Moreover, in vivo imaging of AA in mice was achieved in magnetic mode. The fluorometric/magnetic bi-function sensor for AA detection was introduced, which provided a novel strategy for sensor design based on CDs.


Assuntos
Ácido Ascórbico/análise , Corantes Fluorescentes/química , Imagem por Ressonância Magnética/métodos , Compostos de Manganês/química , Óxidos/química , Pontos Quânticos/química , Espectrometria de Fluorescência/métodos , Animais , Ácido Ascórbico/química , Ácido Ascórbico/metabolismo , Fluorescência , Corantes Fluorescentes/toxicidade , Limite de Detecção , Fenômenos Magnéticos , Masculino , Camundongos Endogâmicos BALB C , Oxirredução , Óxidos/toxicidade , Pontos Quânticos/toxicidade
8.
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
10.
J Photochem Photobiol B ; 195: 1-11, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31029912

RESUMO

Coal is one of the most abundant natural carbonaceous materials. This paper reports a novel oxidative chemical method for the synthesis of high-value carbon dots (CDs) from cheap and abundant low-quality high­sulfur coals for use in high-end applications. These CDs were synthesized by using wet-chemical ultrasonic stimulation-induced process which is environmentally facile and less drastic compared to other chemical methods of production of CDs. The sizes of the synthesized CDs from different types of coal samples were estimated to be in the range of 1-4 nm, 1-6 nm, 2-5 nm, and 10-30 nm. The quantum yield (QY) of the CDs was determined and it was found to be around 3-14%. For high-end field application, the CDs were further tested for toxicity and were reported to be safe for environmental and biological applications. The cell image analysis under the fluorescence microscope further indicated that the synthesized CDs could be used as a promising bio-compatible material for optical-imaging as well as bio-imaging. The CDs showed promising fluorescent sensing property and can be utilized as a good probe for silver ion detection/sensing. The CDs is also found to be a promising reagent for silver nanoparticles synthesis. The results provide a new avenue for large-scale synthesis of CDs.


Assuntos
Materiais Biocompatíveis/química , Carbono/química , Carvão Mineral/análise , Pontos Quânticos/química , Anti-Infecciosos/síntese química , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Materiais Biocompatíveis/síntese química , Materiais Biocompatíveis/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Humanos , Nanopartículas Metálicas/química , Pontos Quânticos/toxicidade , Prata/química , Espectrometria de Fluorescência , Raios Ultravioleta
11.
J Colloid Interface Sci ; 549: 150-161, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31029843

RESUMO

Carbon quantum dots (CQDs) are a novel family of fluorescent materials that could be employed as non-toxic alternatives to molecular fluorescent dyes in biological research and also in medicine. Four different preparation approaches, including microwave assisted heating and solvent refluxing, were explored. In addition to the widely used microwave assisted methods, a simple convenient new procedure is presented here for the particle synthesis. A detailed X-ray photoelectron spectroscopic (XPS) analysis was employed to characterize the composition, and more importantly, the chemical structure of the CQD samples and the interrelation of the characteristic surface chemical groups with the fluorescence properties and with surface polarity was unambiguously established. In vitro cellular internalization experiments documented their applicability as fluorescence labels while non-toxic properties were also approved. It was demonstrated that the adequate water-dispersibility of the particles plays a crucial role in their biological application. The synthetized CQD samples turned to be promising for cellular imaging applications both in laser illuminated flow cytometric measurements and in fluorescence microscopy.


Assuntos
Carbono/química , Corantes Fluorescentes/química , Micro-Ondas , Pontos Quânticos/química , Solventes/química , Linhagem Celular , Corantes Fluorescentes/toxicidade , Humanos , Tamanho da Partícula , Pontos Quânticos/toxicidade , Propriedades de Superfície
12.
Nanoscale ; 11(13): 6192-6205, 2019 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-30874284

RESUMO

Most of the dual nano drug delivery systems fail to enter malignant brain tumors due to a lack of proper targeting systems and the size increase of the nanoparticles after drug conjugation. Therefore, a triple conjugated system was developed with carbon dots (C-dots), which have an average particle size of 1.5-1.7 nm. C-dots were conjugated with transferrin (the targeted ligand) and two anti-cancer drugs, epirubicin and temozolomide, to build the triple conjugated system in which the average particle size was increased only up to 3.5 nm. In vitro studies were performed with glioblastoma brain tumor cell lines SJGBM2, CHLA266, CHLA200 (pediatric) and U87 (adult). The efficacy of the triple conjugated system (dual drug conjugation along with transferrin) was compared to those of dual conjugated systems (single drug conjugation along with transferrin), non-transferrin C-dots-drugs, and free drug combinations. Transferrin conjugated samples displayed the lowest cell viability even at a lower concentration. Among the transferrin conjugated samples, the triple conjugated system (C-dots-trans-temo-epi (C-DT)) was more strongly cytotoxic to brain tumor cell lines than dual conjugated systems (C-dots-trans-temo (C-TT) and C-dots-trans-epi (C-ET)). C-DT increased the cytotoxicity to 86% in SJGBM2 at 0.01 µM while C-ET and C-TT reduced it only to 33 and 8%, respectively. Not only did triple conjugated C-DT increase the cytotoxicity, but also the two-drug combination in C-DT displayed a synergistic effect.


Assuntos
Carbono/química , Portadores de Fármacos/química , Pontos Quânticos/química , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Sinergismo Farmacológico , Epirubicina/química , Epirubicina/farmacologia , Glioblastoma/metabolismo , Glioblastoma/patologia , Humanos , Modelos Biológicos , Pontos Quânticos/toxicidade , Espectrometria de Fluorescência , Temozolomida/química , Temozolomida/farmacologia , Transferrina/química
13.
Nanoscale ; 11(13): 6297-6306, 2019 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-30882825

RESUMO

The abnormal self-assembly of cerebral ß-amyloid (Aß) peptides into toxic aggregates is a hallmark of Alzheimer's disease (AD). Here, we report on multifunctional carbon dots that can chelate Cu(ii) ions, suppress Aß aggregation, and photooxygenate Aß peptides. Copper ions have high relevance to AD pathogenesis, causing Cu(ii)-mediated Aß aggregation and oxidative damage to neuronal cells. For effective conjugation with Cu(ii)-bound Aß complexes, we have designed carbon dots that possess nitrogen (N)-containing polyaromatic functionalities on their surface by employing o-phenylenediamine (OPD) as a polymerization precursor. We demonstrate that the polymerized OPD (pOPD)-derived carbon dots exhibit multiple capabilities against Cu(ii)-mediated Aß aggregation. Furthermore, the pOPD-derived carbon dots exhibited dramatically enhanced absorption and fluorescence upon coordination with Cu(ii) ions and effectively photooxygenated Aß peptides. The photodynamically modulated Aß residues lost the propensity to coordinate with Cu(ii) and to assemble into toxic aggregates. This work demonstrates the potential of carbon dots as a multifunctional ß-sheet breaker and provides a promising anti-amyloidogenic strategy for future Aß-targeted AD treatments.


Assuntos
Peptídeos beta-Amiloides/química , Carbono/química , Cobre/química , Pontos Quânticos/química , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/patologia , Animais , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Humanos , Luz , Células PC12 , Fenilenodiaminas/química , Polimerização , Agregados Proteicos , Pontos Quânticos/uso terapêutico , Pontos Quânticos/toxicidade , Ratos , Espécies Reativas de Oxigênio/metabolismo , Espectrometria de Fluorescência
14.
Ecotoxicol Environ Saf ; 174: 467-474, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-30852312

RESUMO

Cadmium (Cd)-based QDs are well studied owing to their excellent optical properties. The applications of Cd-based QDs in biomedical filed, however, is hindered by its inherent toxicity. In this study, to overcome the inherent toxicity of heavy metals, CdTe QDs were encapsulated with different shells (NAC, MPA and GSH) to reduce the leakage of Cd from the core. We studied the cytotoxicity of the three kinds of CdTe QDs on S. cerevisiae by spectroscopic, electrochemical, microscopic methods and microcalorimetric technique. Results showed that toxicity of CdTe QDs increased with the augment of QD concentration. According to the values of IC50 ((GSH-CdTe QDs (15.3 nmol/L) < MPA-CdTe QDs (56.2 nmol/L) < NAC-CdTe QDs (89.8 nmol/L)), the most toxic one is GSH-CdTe QDs, followed by MPA-CdTe QDs, then NAC-CdTe QDs. The coatings have contribution to their toxicity. The three kinds of QDs with the similar shape (sphere) can enter the cell by the clathrin-mediated endocytosis and lead to the different impairments. The mechanism of cytotoxicity is due to the release of Cd2+ leading elevation of intracellular reactive oxygen species (ROS), which damage mitochondria. The clathrin-mediated endocytosis is a significant factor in determining the toxicity of CdTe QDs.


Assuntos
Compostos de Cádmio/toxicidade , Monitoramento Ambiental/métodos , Pontos Quânticos/toxicidade , Espécies Reativas de Oxigênio/metabolismo , Saccharomyces cerevisiae/efeitos dos fármacos , Telúrio/toxicidade , Compostos de Cádmio/química , Calorimetria , Técnicas Eletroquímicas , Humanos , Microscopia Confocal , Microscopia de Fluorescência , Oxirredução , Pontos Quânticos/química , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Propriedades de Superfície , Telúrio/química
15.
Artigo em Inglês | MEDLINE | ID: mdl-30822735

RESUMO

A fluorescent sulfur and nitrogen dual-doped carbon dots (S,N-CDs) was prepared by a simple and one-step acid-base neutralization and exothermic carbonization method. Hexavalent chromium (Cr(VI)) could effectively quench the fluorescence of S,N-CDs based on inner filter effect (IFE) and dynamic quenching, whereas ascorbic acid (AA) could recover the fluorescence of S,N-CDs/Cr(VI) because of IFE weakening. So an "on-off-on" and label-free nano-probe consecutive determination of Cr(VI) and AA was constructed. This nano-probe system demonstrated excellent selectivity and sensitivity to Cr(VI) and AA with linear range of 0.065-198 µmol/L (3.38-10,296 µg/L) and 6.6-892 µmol/L (1.16-157 mg/L), respectively. Meanwhile, the as-prepared S,N-CDs possess low toxicity and could be used for multi-color cell imaging in SMMC 7721 cells. More importantly, this nano-probe was successfully employed for detection of Cr(VI) in tap water and AA in food samples. In view of its simple detection condition, rapid response, wide linear range, low detection limit and inexpensive instrument, the as-constructed nano-probe system could have a wide range of potential application, including water quality monitoring and evaluation, food inspection and testing and biomedical analysis.


Assuntos
Ácido Ascórbico/análise , Cromo/análise , Pontos Quânticos/química , Espectrometria de Fluorescência/métodos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Frutas/química , Humanos , Limite de Detecção , Modelos Lineares , Pontos Quânticos/toxicidade , Reprodutibilidade dos Testes
16.
Anal Chim Acta ; 1058: 146-154, 2019 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-30851848

RESUMO

A simple fluorescence turn on sensor for the detection of fluoride ion in totally aqueous medium has been developed by integrating boronic acid functionalized carbon quantum dot (BNSCQD) and dopamine. The intense emission of BNSCQD is quenched due to photoelectron transfer (PET) from BNSCQD to dopamine. A remarkable enhancement of emission intensity in presence of F- is achieved due to high reactivity of F- towards boron centre of the BNSCQD-dopamine complex and hence restricting PET between BNSCQD and dopamine. The LOD of our sensor is 0.7 pM. The sensor is not cytotoxic and could be utilised to trace fluoride level changes in human serum as well as in living cells.


Assuntos
Carbono/química , Dopamina/química , Fluoretos/sangue , Pontos Quânticos/química , Ácidos Borônicos/química , Ácidos Borônicos/toxicidade , Água Carbonatada/análise , Linhagem Celular Tumoral , Dentifrícios/análise , Dopamina/toxicidade , Fluorescência , Humanos , Limite de Detecção , Microscopia Confocal/métodos , Microscopia de Fluorescência/métodos , Nitrogênio/química , Pontos Quânticos/toxicidade , Enxofre/química
17.
Food Chem ; 286: 405-412, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-30827625

RESUMO

The formation and properties of nanostructures during food processing have attracted much attention in recent years. Herein, the formation and physicochemical properties of fluorescence carbon dots (CDs) from baked lamb at different baking temperatures (200, 300, and 350 °C) were investigated. The morphology, surface functional groups and fluorescent quantum yield of the CDs were found to be highly dependent on the heating temperature. Biocompatibility of CDs investigation indicated that they were able to disperse onto both the cell membrane and the cytoplasm of HepG2 cells, and alter the cell cycle progression slightly. Moreover, the CDs from baked lamb of 350 °C showed the maximum scavenging capability to free radicals and could protect the cell from oxidative damage in vitro. This contribution represents the first report regarding the properties and formation process of CDs in baked lamb, providing valuable insights into baking temperature influence on physicochemical properties of the CDs.


Assuntos
Culinária , Pontos Quânticos/química , Carne Vermelha , Animais , Carbono/química , Membrana Celular/efeitos dos fármacos , Citoplasma/efeitos dos fármacos , Espectroscopia de Ressonância de Spin Eletrônica , Fluorescência , Radicais Livres/farmacologia , Células Hep G2 , Humanos , Pontos Quânticos/análise , Pontos Quânticos/toxicidade , Carneiro Doméstico , Espectrometria de Fluorescência , Temperatura Ambiente
18.
Mater Sci Eng C Mater Biol Appl ; 98: 535-544, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30813055

RESUMO

In this work, a quick, facile and efficient approach was presented for green synthesis of cadmium telluride quantum dots (CdTe QDs) based on an aqueous extract of the Ficus johannis plant. Two extraction methods involving microwave assisted extraction (MWAE; 90 and 270 w; 15 min) and ultrasonic assisted extraction (USAE; 15 min; 45 °C) were performed as eco-friendly, effective, green and fast techniques for the extract preparation of the fruit's plant. The as-prepared plant extracts were used as natural stabilizing precursors in the synthesis of CdTe QDs. The synthesized QDs were characterized using various techniques. The average particle size of the QDs from the X-ray diffraction patterns was calculated to be 1.2 nm. UV-Vis absorption and fluorescence spectroscopic studies show a wide absorption band from 400 to 425 nm and a maximum emission peak around 470 nm, which confirmed the successful synthesis of CdTe QDs via the applied synthetic method. After synthesis and characterization of the samples, the antimicrobial properties, genotoxicity, toxicity and antifungal activities of the as-prepared CdTe QDs were investigated. In addition, antioxidant properties of the samples (QDs and extracts), were evaluated by different antioxidant assays. The results indicate the significant antimicrobial activity of the extract and CdTe QDs samples, with negligible toxicity and genotoxicity impacts.


Assuntos
Compostos de Cádmio/síntese química , Compostos de Cádmio/toxicidade , Ficus/química , Química Verde/métodos , Micro-Ondas , Pontos Quânticos/toxicidade , Telúrio/toxicidade , Ultrassom/métodos , Antibacterianos/farmacologia , Antifúngicos/farmacologia , Antioxidantes/análise , Bactérias/efeitos dos fármacos , Flavonoides/análise , Fungos/efeitos dos fármacos , Meristema/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Índice Mitótico , Mutagênicos/toxicidade , Cebolas/efeitos dos fármacos , Fenóis/análise , Compostos Fitoquímicos/análise , Pontos Quânticos/ultraestrutura , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier
19.
Sci Total Environ ; 666: 480-489, 2019 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-30802663

RESUMO

The use of quantum dots (QD) in various medical and industrial applications may cause these nanoparticles to leak into waterways and subsequently enter the food chain. Therefore, if we intend to use QD, we must first know their potential environmental implications. In this work, cadmium selenide/zinc sulfide core/shell QD were synthesized, and then, biocompatible, water-dispersed QD were coated with silica (Si-QD). The QD were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) combined with energy-dispersive X-ray spectroscopy (EDX), and UV-Vis absorption analysis, which revealed that these surface-engineered QD have a highly crystalline, homogeneous spherical shape measuring approximately 25 nm. The cytotoxicity of the nanoparticles in the green algae Chlamydomonas reinhardtii was studied by incubating the algae cells with Si-QD and determining the optical density of algal cell culture, cell counts, and cells sizes by microflow cytometry. These measurements indicated that Si-QD are biocompatible up to a concentration of 25 ng/ml. Finally, the cellular uptake of Si-QD into C. reinhardtii was monitored by confocal laser scanning microscopy (CLSM). In conclusion, our results reveal that surface-engineered Cd-QD can penetrate the cells of aquatic organisms, which ensures a serious impact on the food chain and consequently the environment. On the other hand, the results also highlight a new potential method for bioremediation of Cd-QD by green algae, especially C. reinhardtii.


Assuntos
Compostos de Cádmio/toxicidade , Chlamydomonas reinhardtii/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Pontos Quânticos/toxicidade , Compostos de Selênio/toxicidade , Sulfetos/toxicidade , Compostos de Zinco/toxicidade , Nanopartículas Metálicas/química , Pontos Quânticos/química
20.
Ecotoxicol Environ Saf ; 173: 54-62, 2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-30769203

RESUMO

Quantum dots (QDs), considered as a type of excellent semiconductor nanomaterial, are widely employed and have a number of important applications. However, QDs have the potential to produce adverse effects and toxicity with the underlying molecular mechanisms not well understood. Herein, Caenorhabditis elegans was used for in vivo toxicity assessment to detect the reproductive toxicity of CdTe QDs. We found that exposure to CdTe QDs particles (≥ 50 mg/L) resulted in a defect in reproductive capacity, dysfunctional proliferation and differentiation, as well as an imbalance in oogenesis by reducing the number of cells in pachytene and diakinesis. Further, we identified a SPO-11 and PCH-2 mediated toxic mechanism and a GLP-1/Notch mediated protective mechanism in response to CdTe QDs particles (≥ 50 mg/L). Taken together, these results demonstrate the potential adverse impact of CdTe QDs (≥ 50 mg/L) exposure on oogenesis and provide valuable data and guidelines for evaluation of QD biocompatibility.


Assuntos
Compostos de Cádmio/toxicidade , Caenorhabditis elegans/efeitos dos fármacos , Oogênese/efeitos dos fármacos , Pontos Quânticos/toxicidade , Telúrio/toxicidade , Animais , Caenorhabditis elegans/fisiologia , Proteínas de Caenorhabditis elegans/metabolismo , Ciclo Celular/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos
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