Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 28
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Adv Mater ; 31(41): e1904243, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31456250

RESUMO

Ruddlesden-Popper perovskites (RPPs), consisting of alternating organic spacer layers and inorganic layers, have emerged as a promising alternative to 3D perovskites for both photovoltaic and light-emitting applications. The organic spacer layers provide a wide range of new possibilities to tune the properties and even provide new functionalities for RPPs. However, the preparation of state-of-the-art RPPs requires organic ammonium halides as the starting materials, which need to be ex situ synthesized. A novel approach to prepare high-quality RPP films through in situ formation of organic spacer cations from amines is presented. Compared with control devices fabricated from organic ammonium halides, this new approach results in similar (and even better) device performance for both solar cells and light-emitting diodes. High-quality RPP films are fabricated based on different types of amines, demonstrating the universality of the approach. This approach not only represents a new pathway to fabricate efficient devices based on RPPs, but also provides an effective method to screen new organic spacers with further improved performance.

2.
Acta Crystallogr C Struct Chem ; 75(Pt 7): 969-978, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31271386

RESUMO

Metal oxides have a large storage capacity when employed as anode materials for lithium-ion batteries (LIBs). However, they often suffer from poor capacity retention due to their low electrical conductivity and huge volume variation during the charge-discharge process. To overcome these limitations, fabrication of metal oxides/carbon hybrids with hollow structures can be expected to further improve their electrochemical properties. Herein, ZnO-Co3O4 nanocomposites embedded in N-doped carbon (ZnO-Co3O4@N-C) nanocages with hollow dodecahedral shapes have been prepared successfully by the simple carbonizing and oxidizing of metal-organic frameworks (MOFs). Benefiting from the advantages of the structural features, i.e. the conductive N-doped carbon coating, the porous structure of the nanocages and the synergistic effects of different components, the as-prepared ZnO-Co3O4@N-C not only avoids particle aggregation and nanostructure cracking but also facilitates the transport of ions and electrons. As a result, the resultant ZnO-Co3O4@N-C shows a discharge capacity of 2373 mAh g-1 at the first cycle and exhibits a retention capacity of 1305 mAh g-1 even after 300 cycles at 0.1 A g-1. In addition, a reversible capacity of 948 mAh g-1 is obtained at a current density of 2 A g-1, which delivers an excellent high-rate cycle ability.

3.
Nat Commun ; 10(1): 2818, 2019 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-31249295

RESUMO

Metal halide perovskites are emerging as promising semiconductors for cost-effective and high-performance light-emitting diodes (LEDs). Previous investigations have focused on the optimisation of the emissive perovskite layer, for example, through quantum confinement to enhance the radiative recombination or through defect passivation to decrease non-radiative recombination. However, an in-depth understanding of how the buried charge transport layers affect the perovskite crystallisation, though of critical importance, is currently missing for perovskite LEDs. Here, we reveal synergistic effect of precursor stoichiometry and interfacial reactions for perovskite LEDs, and establish useful guidelines for rational device optimization. We reveal that efficient deprotonation of the undesirable organic cations by a metal oxide interlayer with a high isoelectric point is critical to promote the transition of intermediate phases to highly emissive perovskite films. Combining our findings with effective defect passivation of the active layer, we achieve high-efficiency perovskite LEDs with a maximum external quantum efficiency of 19.6%.

4.
Acta Crystallogr C Struct Chem ; 75(Pt 6): 812-821, 2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-31166936

RESUMO

Heterostructures formed by the growth of one kind of nanomaterial in/on another have attracted increasing attention due to their microstructural characteristics and potential applications. In this work, SnS2-SnO2 heterostructures were successfully prepared by a facile hydrothermal method. Due to the enhanced visible-light absorption and efficient separation of photo-generated holes and electrons, the SnS2-SnO2 heterostructures display excellent photocatalytic performance for the degradation of rhodamine (RhB) under visible-light irradiation. Additionally, it is found that the introduction of graphene into the heterostructures further improved photocatalytic activity and stability. In particular, the optimized SnS2-SnO2/graphene photocatalyst can degrade 97.1% of RhB within 60 min, which is about 1.38 times greater than that of SnS2-SnO2 heterostructures. This enhanced photocatalytic activity could be attributed to the high surface area and the excellent electron accepting and transporting properties of graphene, which served as an acceptor of the generated electrons to suppress charge recombination. These results provide a new insight for the design and development of hybrid photocatalysts.

5.
Spectrochim Acta A Mol Biomol Spectrosc ; 219: 232-239, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31048252

RESUMO

Hypochlorous acid (HClO) is one of the most important ROS (reactive oxygen species) and common pollutant in tap-water. However, the determination of HClO with fast response and high sensitivity/selectivity is still an urgent demanding. Here we fabricated a ratiometric fluorescent probe RC based on TBET (through-bond energy transfer) on the platform of coumarin and rhodamine with the thiosemicarbazide group as the linker. This probe could display the characteristic fluorescence emission of coumarin. Upon addition of HClO, the linker was reacted into an oxadiazole, resulting in the opening of spiro-ring of rhodamine. The resultant then gives ratiometric fluorogenic changes. The probe exhibits fast response and high selectivity and sensitivity towards HClO with a low limit of detection (~140 nM). Eventually, RC is successfully applicated for determining spiked HClO in water samples and imaging endogenous HClO in living cells.

6.
Angew Chem Int Ed Engl ; 58(40): 14026-14043, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-30843646

RESUMO

Fluorophores and probes are invaluable for the visualization of the location and dynamics of gene expression, protein expression, and molecular interactions in complex living systems. Rhodamine dyes are often used as scaffolds in biological labeling and turn-on fluorescence imaging. To date, their absorption and emission spectra have been expanded to cover the entire near-infrared region (650-950 nm), which provides a more suitable optical window for monitoring biomolecular production, trafficking, and localization in real time. This review summarizes the development of rhodamine fluorophores since their discovery and provides strategies for modulating their absorption and emission spectra to generate specific bathochromic-shifts. We also explain how larger Stokes shifts and dual-emissions can be obtained from hybrid rhodamine dyes. These hybrid fluorophores can be classified into various categories based on structural features including the alkylation of amidogens, the substitution of the O atom of xanthene, and hybridization with other fluorophores.

7.
J Colloid Interface Sci ; 542: 460-468, 2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-30772508

RESUMO

One-dimensional (1D) heterostructured photocatalysts with controllable texture properties and compositions have attracted increasing interest owing to their unique optical, structural, and electronic advantages. Herein, 1D Co3O4-SnO2 heteronanorods were rationally designed and synthesized through a facile solution-based approach. Benefiting from both of their heterostructural and compositional characteristics, the resulting Co3O4-SnO2 heteronanorods exhibit high photocatalytic performance for the degradation of Rhodamine B (RhB) under visible-light irridation. In particular, the photocatalyst with a Co3O4/SnO2 mass ratio of 1:1 provides the best photocatalytic performance, which can degrade 90% RhB within 120 min. Besides, several reaction parameters affecting RhB degradation, such as churning time, calcination temperature and pH value, are investigated in detail. The enhanced photocatalytic activity can be attributed to the broadening of absorption spectrum to visible-light regions and the efficient charge separation of photogenerated electron-hole pairs due to the formed p-n heterojunctions. The strategy reported here can be able to expand to fabricate other heterostructured photocatalysts for practical applications in the fields of photocatalysis, water splitting, and solar cells.

8.
J Hazard Mater ; 368: 204-213, 2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-30677652

RESUMO

Construction of heterostructures with proper band alignment and effective transport and separation of photogenerated charges is highly expected for photocatalysis. In this work, Ni-doped SnO2-SnS2 heterostructures (NiSnSO) are simply prepared by thermal oxidation of Ni-doped hierarchical SnS2 microspheres in the air. When applied for the photodegradation of organic contaminants, these NiSnSO exhibit excellent catalytic performance and stability due to the following advantages: (1) Ni doping leads to the enhancement of light harvesting of SnS2 in the visible light regions; (2) the formed heterojunctions promote the transport and separation of photogenerated electrons from SnS2 to SnO2; (3) Ni-SnO2 quantum dots facilitate the enrichment of reactants, provide more reactive centers and accelerate product diffusion in the reactive centers; (4) the SnS2 hierarchical microspheres constituted by nanoplates provide abundant active sites, high structural void porosity and accessible inner surface to faciliate the catalytic reactions. As a result, the optimized NiSnSO can photodegrade 92.7% methyl orange within 80 min under the irradiation of simulated sunlight, greatly higher than those of pure SnS2 (29.8%) and Ni-doped SnS2 (52.1%). These results reveal that the combination of heteroatom doping and heterostructure fabrication is a very promising strategy to deliver nanomaterials for effectively photocatalytic applications.

9.
Angew Chem Int Ed Engl ; 58(8): 2261-2265, 2019 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-30589211

RESUMO

Enzyme activity in live cells is dynamically regulated by small-molecule transmitters for maintaining normal physiological functions. A few probes have been devised to measure intracellular enzyme activities by fluorescent imaging, but the study of the regulation of enzyme activity via gasotransmitters in situ remains a long-standing challenge. Herein, we report a three-channel imaging correlation by a single dual-reactive fluorescent probe to measure the dependence of phosphatase activity on the H2 S level in cells. The two sites of the probe reactive to H2 S and phosphatase individually produce blue and green fluorescent responses, respectively, and resonance energy transfer can be triggered by their coexistence. Fluorescent analysis based on the three-channel imaging correlation shows that cells have an ideal level of H2 S to promote phosphatase activity up to its maximum. Significantly, a slight deviation from this H2 S level leads to a sharp decrease of phosphatase activity. The discovery further strengthens our understanding of the importance of H2 S in cellular signaling and in various human diseases.

10.
Spectrochim Acta A Mol Biomol Spectrosc ; 203: 127-131, 2018 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-29864636

RESUMO

Rational design of water-soluble probes for mitochondrial viscosity in practical biological applications remains a challenge. Herein, we described a novel hydro soluble benzothiazole salt derivative MitoSN, which exhibits specifically response and singular sensitivity to the mitochondria viscosity in living Hela cells. MitoSN displays an excellent fluorescence enhancement (ca. 35-fold) with the increase of the viscosity in the water-glycerol system. Moreover, confocal microscopy indicates that MitoSN is sensitive to the local viscosity and selectively stains mitochondria, the body of zebrafish as well. Importantly, MitoSN is capable to identify the viscosity difference of mitochondria in normal and nystatin treated Hela cells. The work provides a useful tool to monitor the changes of viscosity in the mitochondrial microenvironment.


Assuntos
Corantes Fluorescentes/química , Imagem Tridimensional , Mitocôndrias/metabolismo , Água/química , Animais , Sobrevivência Celular , Corantes Fluorescentes/síntese química , Células HeLa , Humanos , Solubilidade , Soluções , Espectrometria de Fluorescência , Viscosidade , Peixe-Zebra
11.
Sci Rep ; 8(1): 6999, 2018 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-29725117

RESUMO

The chelating gadolinium-complex is routinely used as magnetic resonance imaging (MRI) -contrast enhancer. However, several safety issues have recently been reported by FDA and PRAC. There is an urgent need for the next generation of safer MRI-contrast enhancers, with improved local contrast and targeting capabilities. Cerium oxide nanoparticles (CeNPs) are designed with fractions of up to 50% gadolinium to utilize the superior MRI-contrast properties of gadolinium. CeNPs are well-tolerated in vivo and have redox properties making them suitable for biomedical applications, for example scavenging purposes on the tissue- and cellular level and during tumor treatment to reduce in vivo inflammatory processes. Our near edge X-ray absorption fine structure (NEXAFS) studies show that implementation of gadolinium changes the initial co-existence of oxidation states Ce3+ and Ce4+ of cerium, thereby affecting the scavenging properties of the nanoparticles. Based on ab initio electronic structure calculations, we describe the most prominent spectral features for the respective oxidation states. The as-prepared gadolinium-implemented CeNPs are 3-5 nm in size, have r1-relaxivities between 7-13 mM-1 s-1 and show clear antioxidative properties, all of which means they are promising theranostic agents for use in future biomedical applications.

12.
Dalton Trans ; 47(15): 5236-5244, 2018 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-29541711

RESUMO

Designing low-cost electrocatalysts combining the features of outstanding catalytic activity, excellent electrical conductivity, and high chemical stability remains a critical challenge for the large-scale fabrication of dye-sensitized solar cells (DSSCs). Here we report the controlled synthesis of CoS2-CoSe2 heterostructured nanocrystals encapsulated in N-doped carbon hollow nanocubes (CoS2-CoSe2@NC) through simultaneous sulfurization and selenization of polydopamine coated Prussian blue analogs. Benefiting from both structural and compositional characteristics, namely, the synergistic effect of CoS2-CoSe2 heterojunctions, the conductive N-doped carbon coating and the porous structure of the nanocubes, the resultant CoS2-CoSe2@NC nanocubes exhibit excellent electrocatalytic activity and cycling stability toward the generation of I3- ions in DSSCs. A typical device achieves a high power conversion efficiency (PCE) of 8.45% under AM1.5G illumination (100 mW cm-2), superior to that of a standard Pt-based device (8.07%). These results demonstrate that the as-synthesized CoS2-CoSe2@NC nanocubes are promising alternatives to Pt in DSSCs. The work represented here not only provides a promising strategy to design efficient and robust CE catalysts, but also can be extended for synthesizing other novel metal sulfide/selenide hybrid materials for applications in the fields of energy conversion and storage.

13.
Spectrochim Acta A Mol Biomol Spectrosc ; 198: 304-308, 2018 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-29558730

RESUMO

A novel donor-π-acceptor-π-donor type (D-π-A-π-D') Schiff base derivative (L) has been designed and synthesized. The structure of L is confirmed by single-crystal X-ray diffraction analysis as well. The photophysical properties of compound L were comprehensively investigated by using both experimental and theoretical methods. The results indicate that L exhibits large Stokes shift and moderate two-photon action (2PA) cross-section in the near infrared (NIR) region. Furthermore, the confocal microscopy imaging study demonstrates that compound L could penetrate into cells and target the cellular mitochondria compartment. Due to its low cytotoxicity, compound L provides a promising tool for directly lighting up the mitochondria compartment in living HepG2 cells.


Assuntos
Corantes Fluorescentes/química , Imagem Molecular/métodos , Bases de Schiff/química , Cristalografia por Raios X , Corantes Fluorescentes/farmacocinética , Células Hep G2 , Humanos , Microscopia Confocal , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Estrutura Molecular , Fótons , Espectrometria de Fluorescência/métodos , Espectrofotometria Ultravioleta
14.
Org Biomol Chem ; 16(13): 2264-2268, 2018 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-29532844

RESUMO

A two-photon active probe for physiological copper (Cu2+) detection is expected to play an important role in monitoring biological metabolism. Herein, a novel Schiff base derivative (E)-2,2'-((4-((4-(diethylamino)-2-hydroxybenzylidene)amino)phenyl)azanediyl)bis(ethan-1-ol) (L) with remarkable two-photon activity was developed and synthetically investigated. L presents high selectivity and sensitivity for Cu2+ sensing in ethanol/HEPES buffer (v/v, 1 : 1), which is accompanied by the fluorescence switching "off" and subsequently "on" with the addition of EDTA. The mechanism for the detection of Cu2+ is further analyzed using 1H NMR titration, mass spectra and theoretical calculations. Furthermore, since the probe L possesses good photophysical properties, excellent biocompatibility and low cytotoxicity, it is successfully applied to track Cu2+ in the cellular endoplasmic reticulum by two-photon fluorescence imaging, showing its potential value for practical applications in biological systems.

15.
ACS Appl Mater Interfaces ; 9(33): 27607-27617, 2017 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-28767213

RESUMO

Platinum (Pt)-based alloys are considerably promising electrocatalysts for the reduction of I-/I3- and Co2+/Co3+ redox couples in dye-sensitized solar cells (DSSCs). However, it is still challenging to minimize the dosage of Pt to achieve comparable or even higher catalytic efficiency. Here, by taking full advantages of the Mott-Schottky (M-S) effect at the metal-semiconductor interface, we successfully strategize a low-Pt-based M-S catalyst with enhanced electrocatalytic performance and stability for the large-scale application of DSSCs. The optimized M-S electrocatalyst of Ni3S4-Pt2X1 (X = Fe, Ni) heteronanorods is constructed by rationally controlling the ratio of Pt to transition metal in the hybrids. It was found that the electrons transferred from Ni3S4 to Pt2X1 at their interface under the Mott-Schottky effect result in the concentration of electrons onto Pt2X1 domains, which subsequently accelerates the regeneration of both I-/I3- and Co2+/Co3+ redox shuttles in DSSCs. As a result, the DSSC with Ni3S4-Pt2Fe1 manifests an impressive power conversion efficiency (PCE) of 8.79% and 5.56% for iodine and cobalt-based electrolyte under AM1.5G illumination, respectively. These PCEs are obviously superior over those with Ni3S4-Pt, PtFe, Ni3S4, and pristine Pt electrodes. The strategy reported here is able to be further expanded to fabricate other low-Pt-alloyed M-S catalysts for wider applications in the fields of photocatalysis, water splitting, and heterojunction solar cells.

16.
Anal Chim Acta ; 933: 189-95, 2016 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-27497012

RESUMO

We strategize to utilize the precursors of (imino)coumarin fluorophores to deliver novel reactive Cu(+) probes, where tris[(2-pyridyl)-methyl] amine (TPA) works as a reactive receptor towards Cu(+). To verify this strategy, CP1, a representative probe and relevant sensing behaviors towards Cu(+) are presented here. CP1 features good solubility and fast response for monitoring labile copper in aqueous solution and live cells. The sensing mechanism of CP1 is determined by HPLC titration and mass spectrometric analysis. The probe CP1 exhibits a 60-fold fluorescence enhancement and a detection limitation of 10.8 nM upon the detection of Cu(+). CP1 is further applied for imaging labile copper in live cells. This work provides a starting point for future development of Cu(+) probes, based on in situ formation of (imino)coumarin scaffolds, as well as their further investigations of copper signaling and biological events.


Assuntos
Cobre/análise , Cumarínicos/química , Corantes Fluorescentes/química , Iminas/química , Piridinas/química , Estrutura Molecular
17.
Anal Chim Acta ; 919: 85-93, 2016 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-27086103

RESUMO

A new colorimetric and fluorogenic probe (RN3) based on rhodamine-B has been successfully designed and synthesized. It displays a selective response to Hg(2+) in the aqueous buffer solution over the other competing metals. Upon addition of Hg(2+), the solution of RN3 exhibits a 'naked eye' observable color change from colorless to red and an intensive fluorescence with about 105-fold enhancement. The changes in the color and fluorescence are ascribed to the ring-opening of spirolactam in rhodamine fluorophore, which is induced by a binding of the constructed receptor to Hg(2+) with the association and dissociation constants of 0.22 × 10(5) M(-1) and 25.2 µM, respectively. The Job's plot experiment determines a 1:1 binding stoichiometry between RN3 and Hg(2+). The resultant "turn-on" fluorescence in buffer solution, allows the application of a method to determine Hg(2+) levels in the range of 4.0-15.0 µM, with the limit of detection (LOD) calculated at 60.7 nM (3σ/slope). In addition, the fluorescence 'turn-off' and color 'fading-out' happen to the mixture of RN3-Hg(2+) by further addition of I(-) or S(2-). The reversible switching cycles of fluorescence intensity upon alternate additions of Hg(2+) and S(2-) demonstrate that RN3 can perform as an INHIBIT logic gate. Furthermore, the potential of RN3 as a fluorescent probe has been demonstrated for cellular imaging.


Assuntos
Corantes Fluorescentes/química , Lógica , Mercúrio/análise , Imagem Molecular/métodos , Rodaminas/química , Sobrevivência Celular/efeitos dos fármacos , Colorimetria , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/farmacologia , Células HeLa , Humanos , Estrutura Molecular , Rodaminas/síntese química , Rodaminas/farmacologia , Espectrometria de Fluorescência
18.
Environ Toxicol Pharmacol ; 42: 183-9, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26871964

RESUMO

Zebrafish embryos were used to investigate the developmental effects of sulfide. Mortality, teratogenic effects, and developmental parameters of early developmental embryos were recorded. The biodistribution of sulfide in developing zebrafish embryos and larvae were measured through fluorescence imaging. The influences of sulfide on the cardiac function and development velocity of zebrafish embryos were dependent on sulfide concentration. Heart rate and development velocity increased with exposure to lower sulfide concentrations, which may be attributed to the cardioprotective properties of H2S. Meanwhile, heart rate and development velocity decreased, whereas pericardial edema, yolk sac edema, and trunk abnormalities occurred with exposure to higher sulfide concentrations. Sulfide accumulated in the blastoderm of early developmental embryos and was then transported to the yolk sac and yolk extension with the embryonic development. Finally, sulfide was transferred from the yolk to the eyes of zebrafish larvae. The details of mechanism of sulfide toxicity require further research.


Assuntos
Embrião não Mamífero/efeitos dos fármacos , Sulfetos/toxicidade , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/embriologia , Animais , Desenvolvimento Embrionário/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos
19.
Nanoscale ; 6(5): 2953-63, 2014 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-24480995

RESUMO

Uniform, highly water-dispersible and ultra-small Fe3O4 nanoparticles were synthesized via a modified one-step coprecipitation approach. The prepared Fe3O4 nanoparticles not only show good magnetic properties, long-term stability in a biological environment, but also exhibit good biocompatibility in cell viability and hemolysis assay. Due to the ultra-small sized and highly water-dispersibility, they exhibit excellent relaxivity properties, the 1.7 nm sized Fe3O4 nanoparticles reveal a low r2/r1 ratio of 2.03 (r1 = 8.20 mM(-1) s(-1), r2 = 16.67 mM(-1) s(-1)); and the 2.2 nm sized Fe3O4 nanoparticles also appear to have a low r2/r1 ratio of 4.65 (r1 = 6.15 mM(-1) s(-1), r2 = 28.62 mM(-1) s(-1)). This demonstrates that the proposed ultra-small Fe3O4 nanoparticles have great potential as a new type of T1 magnetic resonance imaging contrast agents. Especially, the 2.2 nm sized Fe3O4 nanoparticles, have a competitive r1 value and r2 value compared to commercial contrasting agents such as Gd-DTPA (r1 = 4.8 mM(-1) s (-1)), and SHU-555C (r2 = 69 mM(-1) s(-1)). In vitro and in vivo imaging experiments, show that the 2.2 nm sized Fe3O4 nanoparticles exhibit great contrast enhancement, long-term circulation, and low toxicity, which enable these ultra-small sized Fe3O4 nanoparticles to be promising as T1 and T2 dual contrast agents in clinical settings.


Assuntos
Meios de Contraste/síntese química , Óxido Ferroso-Férrico/química , Imagem por Ressonância Magnética , Nanopartículas de Magnetita/química , Água/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Meios de Contraste/química , Meios de Contraste/toxicidade , Eritrócitos/efeitos dos fármacos , Eritrócitos/metabolismo , Gadolínio DTPA/química , Hemólise/efeitos dos fármacos , Humanos , Nanopartículas de Magnetita/toxicidade , Tamanho da Partícula
20.
Chemistry ; 19(38): 12658-67, 2013 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-24175343

RESUMO

Water-dispersible and luminescent gadolinium oxide (GO) nanoparticles (NPs) were designed and synthesized for potential dual-modal biological imaging. They were obtained by capping gadolinium oxide nanoparticles with a fluorescent glycol-based conjugated carboxylate (HL). The obtained nanoparticles (GO-L) show long-term colloidal stability and intense blue fluorescence. In addition, L can sensitize the luminescence of europium(III) through the so-called antenna effect. Thus, to extend the spectral ranges of emission, europium was introduced into L-modified gadolinium oxide nanoparticles. The obtained EuIII-doped particles (Eu:GO-L) can provide visible red emission, which is more intensive than that without L capping. The average diameter of the monodisperse modified oxide cores is about 4 nm. The average hydrodynamic diameter of the L-modified nanoparticles was estimated to be about 13 nm. The nanoparticles show effective longitudinal water proton relaxivity. The relaxivity values obtained for GO-L and Eu:GO-L were r1=6.4 and 6.3 s−1 mM−1 with r2/r1 ratios close to unity at 1.4 T. Longitudinal proton relaxivities of these nanoparticles are higher than those of positive contrast agents based on gadolinium complexes such as Gd-DOTA, which are commonly used for clinical magnetic resonance imaging. Moreover, these particles are suitable for cellular imaging and show good biocompatibility.


Assuntos
Meios de Contraste/química , Gadolínio/química , Nanopartículas Metálicas/química , Sobrevivência Celular/efeitos dos fármacos , Meios de Contraste/síntese química , Meios de Contraste/toxicidade , Európio/química , Células HeLa , Compostos Heterocíclicos com 1 Anel/química , Humanos , Imagem por Ressonância Magnética , Nanopartículas Metálicas/toxicidade , Nanopartículas Metálicas/ultraestrutura , Microscopia Confocal , Propriedades de Superfície , Água/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA