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1.
Anal Bioanal Chem ; 411(17): 3979-3988, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31089787

RESUMO

Herein, a universal and multifunctional fluorescence sensor platform is designed by the interaction of aggregation/dispersion gold nanoparticles (AuNPs) with Tb-metal-organic frameworks (Tb-MOFs). It is found that the dispersed AuNPs rather than the aggregated ones can quench effectively the fluorescence of Tb-MOFs, and the quenching process presumably involves the mechanism of inner filter effect (IFE), dynamic quenching effect (DQE), and fluorescence resonance energy transfer (FRET). The different affinities of aptamer and aptamer-target complex toward AuNPs are employed to modulate the fluorescence signal change of Tb-MOFs. As the proof of concept, prostate-specific antigen (PSA), an efficient tumor indicator for prostate cancer, is selected as the target. At first, the PSA aptamer can protect AuNPs against salt-induced aggregation, leading to the fluorescence of Tb-MOFs quenching. Subsequently, upon PSA introduction, the rigid aptamer-PSA complex is formed and cannot stabilize AuNPs in high salt conditions, so the AuNPs aggregate significantly and the fluorescence of Tb-MOFs is restored. The linear range of PSA is achieved from 1 to 100 ng/mL with a detection limit of 0.36 ng/mL. Finally, this method has been validated to be sensitive and specific for PSA in human urine samples. Graphical abstract.


Assuntos
Técnicas Biossensoriais , Ouro/química , Imunoensaio/métodos , Nanopartículas Metálicas/química , Estruturas Metalorgânicas/química , Antígeno Prostático Específico/análise , Térbio/química , Fluorescência , Humanos , Limite de Detecção , Masculino , Microscopia Eletrônica de Transmissão , Antígeno Prostático Específico/urina , Espectroscopia de Infravermelho com Transformada de Fourier , Ressonância de Plasmônio de Superfície
2.
ACS Appl Mater Interfaces ; 11(17): 15998-16005, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30951283

RESUMO

Lanthanide coordination polymers have been recently regarded as attractive sensing materials because of their selectivity, high sensitivity, and rapid response ability. In this research, the multiporous terbium phosphonate coordination polymer microspheres (TbP-CPs) were prepared as a novel fluorescent probe, which showed a fluorescence turn-on response capability for the detection of the trace anthrax biomarker dipicolinate acid (DPA). The morphology and chemical composition of as-prepared TbP-CPs were characterized in detail. The TbP-CPs have the vegetable-flower-like structure and microporous surface. In addition, the as-prepared TbP-CPs not only possess the merits of convenience and simple preparation with high yield but also have the excellent characters as fluorescent probes, such as high stability, good selectivity, and rapid detection ability within 30 s. This proposed sensor could detect DPA with a linear relationship in concentrations ranging from 0 to 8.0 µM and a high detection sensitivity of 5.0 nM. Furthermore, the successful applications of DPA detection in urine and bovine serum were demonstrated. As a result, the recovery ranged from 93.93-101.6%, and the relative standard deviations (RSD) were less than 5%.


Assuntos
Antraz/diagnóstico , Biomarcadores/análise , Corantes Fluorescentes/química , Microesferas , Polímeros/química , Térbio/química , Animais , Antraz/microbiologia , Bacillus anthracis/metabolismo , Biomarcadores/sangue , Biomarcadores/urina , Técnicas Biossensoriais/métodos , Humanos , Organofosfonatos/química , Ácidos Picolínicos/análise , Ácidos Picolínicos/sangue , Ácidos Picolínicos/urina , Porosidade , Espectrometria de Fluorescência
3.
J Nanobiotechnology ; 17(1): 54, 2019 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-30992018

RESUMO

BACKGROUND: Nanomaterials that exhibit intrinsic enzyme-like characteristics have shown great promise as potential antibacterial agents. However, many of them exhibit inefficient antibacterial activity and biosafety problems that limit their usefulness. The development of new nanomaterials with good biocompatibility and rapid bactericidal effects is therefore highly desirable. Here, we show a new type of terbium oxide nanoparticles (Tb4O7 NPs) with intrinsic oxidase-like activity for in vitro and in vivo antibacterial application. RESULTS: We find that Tb4O7 NPs can quickly oxidize a series of organic substrates in the absence of hydrogen peroxide. The oxidase-like capacity of Tb4O7 NPs allows these NPs to consume antioxidant biomolecules and generate reactive oxygen species to disable bacteria in vitro. Moreover, the in vivo experiments showed that Tb4O7 NPs are efficacious in wound-healing and are protective of normal tissues. CONCLUSIONS: Our results reveal that Tb4O7 NPs have intrinsic oxidase-like activity and show effective antibacterial ability both in vitro and in vivo. These findings demonstrate that Tb4O7 NPs are effective antibacterial agents and may have a potential application in wound healing.


Assuntos
Antibacterianos/química , Escherichia coli , Nanopartículas Metálicas/química , Óxidos/química , Oxirredutases/química , Staphylococcus aureus , Térbio/química , Cicatrização , Animais , Antibacterianos/farmacologia , Materiais Biocompatíveis/química , Sobrevivência Celular , Escherichia coli/efeitos dos fármacos , Hemólise , Células Endoteliais da Veia Umbilical Humana , Humanos , Camundongos Endogâmicos BALB C , Óxidos/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Staphylococcus aureus/efeitos dos fármacos , Térbio/farmacologia
4.
Spectrochim Acta A Mol Biomol Spectrosc ; 214: 261-268, 2019 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-30785046

RESUMO

Highly crystalline polyethylene glycol (PEG) coated Tb3+ doped ZnS nanoparticles have been synthesized and successfully used for norfloxacin sensing. The crystallographic and morphological analyses of PEG coated Tb3+ doped ZnS nanoparticles were performed by X-ray diffraction and Transmission electron microscopy, respectively. The confirmation of Tb3+ doping in ZnS host matrix was done by emission spectroscopy and energy dispersive X-ray spectroscopy. Further, the interaction of norfloxacin with PEG coated Tb3+ doped ZnS nanomaterials was confirmed by optical analysis: spectrophotometrically and spectrofluorimetrically. Norfloxacin sensing was measured by luminescence intensity which increased with increase in concentration of norfloxacin in range from 2.0 × 10-9-8.0 × 10-7 mol L-1, with its correlation coefficient 0.9991. The detection limit of proposed method was 0.05 × 10-9 mol L-1. The developed luminescence method was successfully applied for the determination of norfloxacin using PEG coated Tb3+ doped ZnS nanoparticles in urine and pharmaceutical samples.


Assuntos
Materiais Revestidos Biocompatíveis/química , Nanoestruturas/química , Norfloxacino , Polietilenoglicóis/química , Sulfetos/química , Térbio/química , Compostos de Zinco/química , Animais , Humanos , Norfloxacino/análise , Norfloxacino/farmacocinética , Norfloxacino/urina , Espectrometria de Fluorescência/métodos
5.
Spectrochim Acta A Mol Biomol Spectrosc ; 214: 459-468, 2019 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-30807944

RESUMO

A new, simple, rapid, highly sensitive and selective and non-enzymatic fluorometric method for direct determination of glucose in real samples was developed. The method was based on the inhibition of fluorescence resonance energy transfer (FRET) process between terbium (III)-1, 10-phenanthroline (Tb-phen) complex and silver nanoparticles (AgNPs). Upon the addition of glucose, the quenched FRET-based fluorescence of Tb-phen complex was gradually recovered by glucose via its strong adsorption on the surface of AgNPs and removal of Tb-phen complex from AgNPs surface. Therefore the fluorescence of Tb-phen complex switched to "turn-on" state. Under the optimum conditions, a linear relationship was obtained between the enhanced fluorescence intensity and glucose concentration in the range of (5-900) × 10-8 M with the detection limit of 1.94 × 10-8 M. The proposed sensing system was successfully applied to determine glucose in the spiked normal and diabetic patient serum samples after deproteinization with acetonitrile. Analytical recoveries from treated serum samples were in the range of 99.97-104.80% and 92.14-105.43%, respectively. The common interfering species, such as ascorbic acid, fructose and galactose did not cause interior interference due to unique emission properties of Tb-phen complex probe. Also the interaction of the Tb-phen complex with AgNPs, which led to the fluorescence intensity quenching of the complex, was further examined by FTIR technique. In short, as compared to most of the existing methods, the newly proposed method, provides some advantages and makes it promising for the direct rapid screening of glucose residues of real samples in clinical diagnosis of diabetes, as an alternative approach to the other exiting optical and electrochemical methods.


Assuntos
Glicemia/análise , Técnicas Eletroquímicas/métodos , Transferência Ressonante de Energia de Fluorescência/métodos , Nanopartículas Metálicas/química , Prata/química , Glicemia/metabolismo , Humanos , Fenantrolinas/química , Sensibilidade e Especificidade , Térbio/química
6.
Luminescence ; 34(3): 382-386, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30784183

RESUMO

An energy transfer process from Ce3+ to Tb3+ ions was successfully achieved in a Li2 SO4 -Al2 (SO4 )3 mixed-sulphate system. A wet-chemical synthesis was employed to prepare the Li2 SO4 -Al2 (SO4 )3 system by doping Ce3+ and Tb3+ ions individually as well as collectively. The phases were identified using X-ray diffraction studies. The as-prepared samples were characterized by FT-IR and photoluminescence measurements. Green-light emission was exhibited by Ce3+ , Tb3+ co-doped Li2 SO4 -Al2 (SO4 )3 system, thus, indicating its potential as a material for display devices or in the lamp industry.


Assuntos
Compostos de Alúmen/química , Cério/química , Compostos de Lítio/química , Sulfatos/química , Térbio/química , Transferência de Energia , Luz , Luminescência , Espectroscopia de Infravermelho com Transformada de Fourier
7.
Molecules ; 24(4)2019 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-30791537

RESUMO

(Gd0.93-xTb0.07Eux)2O3 (x = 0⁻0.10) phosphors shows great potential for applications in the lighting and display areas. (Gd0.93-xTb0.07Eux)2O3 phosphors with controlled morphology were prepared by a hydrothermal method, followed by calcination at 1100 °C. XRD, FE-SEM, PL/PLE, luminescent decay analysis and thermal stability have been performed to investigate the Eu3+ content and the effects of hydrothermal conditions on the phase variation, microstructure, luminescent properties and energy transfer. Optimum excitation wavelength at ~308 nm nanometer ascribed to the 4f8-4f75d¹ transition of Tb3+, the (Gd0.93-xTb0.07Eux)2O3 phosphors display both Tb3+and Eu3+ emission with the strongest emission band at ~611 nm. For increasing Eu3+ content, the Eu3+ emission intensity increased as well while the Tb3+ emission intensity decreased owing to Tb3+→Eu3+ energy transfer. The energy transfer efficiencies were calculated and the energy transfer mechanism was discussed in detail. The lifetime for both the Eu3+ and Tb3+ emission decreases with the Eu3+ addition, the former is due to the formation of resonant energy transfer net, and the latter is because of contribution by Tb3+→Eu3+ energy transfer. The phosphor morphology can be controlled by adjusting the hydrothermal condition (reaction pH), and the morphological influence to the luminescent properties (PL/PLE, decay lifetime, etc.) has been studied in detail.


Assuntos
Európio/química , Metais Terras Raras/química , Óxidos/química , Fósforo/química , Térbio/química
8.
Molecules ; 24(4)2019 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-30769859

RESUMO

Assembling Ln3+(HPBAn) (Ln = Eu or Tb, HPBA = N-(2-pyridinyl)benzoylacetamide) in the cavities of zeolite Y (ZY) via the "ship-in-a-bottle" strategy leads to the formation of novel luminescent composite, Ln(HPBAn)@ZY, whose luminescence can be easily modulated by ammonia on the basis of the energy level variation of HPBA after deprotonation process. Additionally the bimetallic complex doping sample, Eu0.5Tb0.5(HPBAn)@ZY, show great potential as self-referencing luminescent sensor for detecting low ammonia concentration of 10-12⁻0.25 wt%.


Assuntos
Amônia/química , Medições Luminescentes , Zeolitas/química , Európio/química , Luminescência , Térbio/química , Difração de Raios X , Ítrio/química
9.
Anal Chim Acta ; 1049: 152-160, 2019 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-30612646

RESUMO

Time-gated luminescence (TGL) bioassay technique using luminescent lanthanide complexes as probes has exhibited excellent practicability in detection of various analytes in autofluorescence-rich biosamples. Herein, a novel copper(II)-coupled lanthanide complex-based luminescence probe has been developed for the ratiometric TGL detection of hydrogen sulfide (H2S) in vitro and in vivo. The probe is constructed based on a dual-functional ligand that was synthesized by conjugating di(2-picolyl)amine with terpyridine polyacid (DATP) using the "click chemistry" method. The as-prepared ligand can coordinate to Eu3+ and Tb3+ ions with its terpyridine polyacid moiety to display long-lived emissions of Eu3+ and Tb3+ ions, while the further coordination of its di(2-picolyl)amino moiety to Cu2+ induces to the luminescence quenching of the Eu3+ complexes, which allows the probe consisting of the heterometallic Cu2+-DATP-Eu3+/Tb3+ complexes to be constructed. After the probe was reacted with H2S to lead to the release of Cu2+ from the complexes, the emission of Eu3+ at 610 nm was remarkably enhanced, while that of Tb3+ at 540 nm was changed slightly. This luminescence response feature allowed the probe to be conveniently applied for the ratiometric TGL determination of H2S with I610/I540 as the signal. The applicability of the probe for quantitative detection of H2S in human sera as well as for imaging of H2S in living cells and zebrafish were evaluated. All of the results proved the potential of the probe for in vitro and in vivo applications.


Assuntos
Complexos de Coordenação/química , Cobre/química , Sulfeto de Hidrogênio/sangue , Substâncias Luminescentes/química , Medições Luminescentes/métodos , Animais , Química Click , Complexos de Coordenação/síntese química , Európio/química , Células HeLa , Humanos , Ligantes , Limite de Detecção , Luminescência , Substâncias Luminescentes/síntese química , Térbio/química , Peixe-Zebra
10.
Mikrochim Acta ; 186(1): 45, 2019 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-30610384

RESUMO

A ratiometric fluorometric method is described for the determination of arsenate via its inhibitory effect on the activity of the enzyme acid phosphatase. A nanoprobe was designed that consists of CdSe/ZnS quantum dots (QDs) coated with the terbium(III) complex of guanosine monophosphate (Tb-GMP). The nanoprobe was synthesized from carboxylated QDs, Tb(III) and GMP via binding of Tb(III) by both the carboxy and the phosphate groups. The nanoprobe, under single-wavelength excitation (at 280 nm), displays dual (red and green) emission, with peaks at around 652 nm from the QDs, and at 547 nm from the Tb-GMP coordination polymers. It is shown to be a viable nanoprobe for fluorometric determination of As(V) detection through it inhibitory action on the activity of acid phosphatase (ACP). The enzyme destroys the Tb-GMP structure via hydrolysis of GMP, and hence the fluorescence of the Tb-GMP complex is quenched. In contrast, the fluorescence of the CdSe/ZnS QDs remains inert to ACP. It therefore can serve as an internal reference signal. In the presence of arsenate (an analog of phosphate), the activity of ACP is inhibited due to competitive binding. Thus, hydrolysis of GMP is prevented. These findings were used to design a ratiometric fluorometric method for the quantification of As(V). The ratio of fluorescences at 547 and 652 nm increases linearly in the 0.5 to 200 ppb As(V) concentation range, and the limit of detection is 0.39 ppb. Under a UV lamp, the probe shows distinguishable color from green to red on increasing the concentration of As(V). Graphical abstract Schematic illustration of CdSe/ZnS quantum dot coated with carboxy-PEG and modified with the terbium(III)-GMP complex as a fluorescent nanoprobe for ratiometric determination of arsenate via its inhibition of ACP activity.


Assuntos
Arseniatos/análise , Fluorescência , Guanosina Monofosfato/química , Sondas Moleculares/química , Pontos Quânticos/química , Térbio/química , Fosfatase Ácida/antagonistas & inibidores , Compostos de Cádmio/química , Fluorometria/métodos , Sulfetos/química , Compostos de Zinco/química
11.
Anal Bioanal Chem ; 411(7): 1375-1381, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30645663

RESUMO

A sensitive fluorescent analytical method for the detection of dopamine (DA) was developed based on surface-enhanced Tb(III)/La(III) co-luminescence using silver nanoflowers (AgNFs). Anisotropic AgNFs show strong surface-enhanced fluorescence effect owing to the abundant sharp tips. Tb(III)/La(III)-DA complexes mainly bind to the sharp tips of AgNFs and thus shorten the distance between the complexes. The shortened distance gives rise to obvious surface-enhanced Tb(III)/La(III) co-luminescence effect. In this work, AgNFs offer many superior properties, such as enhanced intrinsic green fluorescence of Tb(III) (λex/λem = 310/546 nm), increased fluorescence lifetime, and improved energy transfer efficiency. Under the optimum conditions, the fluorescence intensity is linearly correlated with the concentration of DA in the range of 0.80-10 nM (R2 = 0.9970), and the detection limit is 0.34 nM (S/N = 3). The fluorescent nanoprobe was successfully applied to the determination of DA in human serum samples with recoveries ranging from 99.1 to 102.6%. Graphical abstract.


Assuntos
Dopamina/sangue , Corantes Fluorescentes/química , Lantânio/química , Nanoestruturas/química , Prata/química , Térbio/química , Humanos , Limite de Detecção , Luminescência , Nanoestruturas/ultraestrutura , Espectrometria de Fluorescência/métodos
12.
Inorg Chem ; 58(1): 524-534, 2019 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-30547593

RESUMO

A novel three-dimensional microporous framework, [Tb(pddb)phen(ox)0.5] n (Tb-MOF), was synthesized hydrothermally with V-shaped 4,4'-(pyridine-2,6-diyl)dibenzoic acid (H2pddb), oxalate (ox), and 1,10-phenanthroline (phen). The framework of Tb-MOF features one-dimensional channels functionalized with pyridine-N Lewis base groups and the absence of coordinated and lattice water molecules in the structure. The Tb-MOF exhibits high thermostability (up to 385 °C) and chemical stability in a wide pH range (4-11) and common organic solvents as well as boiling water. The luminescence investigations of the Tb-MOF in common solvents, water with different pH values, and inorganic ions were performed. Results show that the Tb-MOF has high luminescence stability and the ability to probe Fe3+ ions. Significantly, the Tb-MOF with particularly high water stability can be first developed as a highly selective and sensitive luminescent sensor for the biomarker 2-thiazolidinethione-4-carboxylic acid (TTCA) via fluorescence quenching. The low detection limit (1 ppm), reusability, and high antidisturbance together make the Tb-MOF become a promising sensor for the practical detection of TTCA in urine systems, and for the first time realize the detection of urinary TTCA through fluorescence spectrometry based on an Ln-MOF sensor.


Assuntos
Biomarcadores/urina , Estruturas Metalorgânicas/química , Térbio/química , Tiazolidinas/urina , Dissulfeto de Carbono/toxicidade , Fluorescência , Limite de Detecção , Estruturas Metalorgânicas/síntese química , Estruturas Metalorgânicas/efeitos da radiação , Síndromes Neurotóxicas/diagnóstico , Exposição Ocupacional , Piridinas/síntese química , Piridinas/química , Piridinas/efeitos da radiação , Espectrometria de Fluorescência/métodos , Raios Ultravioleta
13.
Spectrochim Acta A Mol Biomol Spectrosc ; 211: 348-355, 2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30583166

RESUMO

Tb-doped Y2O3 microspheres (MSs) were prepared via a homogeneous thermal degradation process at a low temperature and then coated with a nanosilica shell (Y2O3:Tb@SiO2) using a sol-gel process. The core MSs were highly crystalline and spherical with a porous surface, single cubic phase, and particle size of 100-250 nm. Transmission electron microscopy (TEM) images clearly showed the spherical shape of the as-prepared core MSs, which were fully covered with a thick and mesoporous nanosilica shell. Fourier transform infrared (FTIR) spectra displayed the well-resolved infrared absorption peaks of silica (SiO, SiOSi, etc.), confirming the presence of the silica surface coating. The core MSs retained their spherical shape even after heat treatment and subsequent silica surface coating. It was observed that the core/shell MSs are easily dispersible in aqueous media and form a semi-transparent colloidal solution. Ultraviolet/visible and zeta potential studies were tested to prove the changes in the surface chemistry of the as-designed core/shell MSs and compare with their core counterpart. The growth of the amorphous silica shell not only increased the particle size but also enhanced remarkably the solubility and colloidal stability of the MSs in aqueous media. The strongest emission lines originating from the characteristic intra-shell 4f-4f electronic transitions of Tb ions were quenched after silica layer deposition, but the MSs still showed strong green (5D4 → 7F5 at 530-560 nm as most dominant) emission efficiency, which indicates great potential in fluorescent bio-probes. The emission intensity is discussed in relation to the quenching mechanism induced by surface silanol (Si-OH) groups, particle size, and surface charge.


Assuntos
Substâncias Luminescentes/química , Dióxido de Silício/química , Térbio/química , Ítrio/química , Difusão Dinâmica da Luz , Microscopia Eletrônica de Transmissão , Microesferas , Nanoconchas/química , Tamanho da Partícula , Silanos/química , Solubilidade , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Termogravimetria , Difração de Raios X
14.
Luminescence ; 34(1): 90-97, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30575272

RESUMO

Four novel salicyloylhydrazone derivatives and their terbium(III) complexes were synthesized and characterized. The thermal analysis results showed that the terbium(III) complexes possessed good thermal stability. The fluorescence research results showed that the terbium(III) complex substituted by phenyl possessed the best fluorescence intensity among them, and its fluorescence quantum yield was also the highest. The exploration of the electrochemical properties indicated that the introduction of electron-donating groups to the ligand can increase the highest occupied molecular orbital (HOMO) energy levels and decrease the oxidation potential of the corresponding terbium(III) complexes. The introduction of electron-withdrawing groups to the ligand can reduce their HOMO energy levels and increase their oxidation potential. The results showed that the terbium(III) complexes are good candidates for luminescent material.


Assuntos
Hidrazonas/química , Substâncias Luminescentes/química , Térbio/química , Eletroquímica/métodos , Hidrazonas/síntese química , Ligantes , Substâncias Luminescentes/síntese química , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Estrutura Molecular , Espectrometria de Fluorescência , Espectrofotometria Infravermelho , Espectrofotometria Ultravioleta
15.
Inorg Chem ; 58(1): 495-505, 2019 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-30561998

RESUMO

An in-depth study of the interaction of a trinuclear terbium(III)-dizinc(II) complex with an array of nucleotides differing in the type of nucleobase and number of phosphate groups, as well as cyclic versus acyclic variants, is presented. The study examined the nature of the interaction and the efficiency at which guanine was able to sensitize terbium(III) luminescence. Competitive binding and titration studies were performed to help establish the nature/mode of the interactions. These established that (1) interaction occurs by the coordination of phosphate groups to zinc(II) (in addition to uridine in the case of uridine monophosphate), (2) acyclic nucleotides bind more strongly than cyclic counterparts because of their higher negative charge, (3) guanine-containing nucleotides are able to sensitize terbium(III) luminescence with the efficiency of sensitization following the order guanosine monophosphate (GMP) > guanosine diphosphate > guanosine triphosphate because of the mode of binding, and (4) nucleoside monophosphates bind to a single zinc(II) ion, whereas di- and triphosphates appear to bind in a bridging mode between two host molecules. Furthermore, it has been shown that guanine is a sensitizer of terbium(III) luminescence. On the basis of the ability of GMP to effectively sensitize terbium(III)-based luminescence while cyclic GMP (cGMP) does not, the complex has been utilized to monitor the catalytic conversion of cGMP to GMP by a phosphodiesterase enzyme in real time using time-gated luminescence on a benchtop fluorimeter. The complex has the potential to find broad application in monitoring the activity of enzymes that process nucleotides (co)substrates, including high-throughput drug-screening programs.


Assuntos
Complexos de Coordenação/química , Guanosina Monofosfato/química , Diester Fosfórico Hidrolases/análise , Térbio/química , Zinco/química , Complexos de Coordenação/síntese química , Complexos de Coordenação/efeitos da radiação , GMP Cíclico/química , Ensaios Enzimáticos , Luz , Luminescência , Espectrofotometria , Água/química
16.
J Phys Chem Lett ; 9(15): 4379-4384, 2018 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-30016106

RESUMO

Photoluminescence (PL) multiplexing usually relies on spectral or temporal separation. A combination into higher-order multiplexing for biosensing is extremely challenging because the PL intensity is required for target quantification at very low concentrations and the interplay of color, lifetime, and intensity must be carefully adapted. Here, we demonstrate time-gated Förster resonance energy transfer (TG-FRET) from a long-lifetime Tb complex to Cy3.5 and Cy5.5 dyes for spectrotemporal multiplexing of four different DNA targets in the same sample by single-color excitation and two-color detection. We used rolling circle amplification (RCA) for high specificity and sensitivity and for placing Tb donors and dye acceptors at controlled distances within the amplified DNA concatemers. This precise distance tuning led to target-specific PL decays of the FRET pairs and simple, separation-free, and higher-order multiplexed quantification of DNA. The RCA-FRET DNA assay could distinguish very homologous target sequences and provided limits of detection down to 40 zeptomoles (300 aM).


Assuntos
DNA de Cadeia Simples/análise , Transferência Ressonante de Energia de Fluorescência/métodos , Técnicas de Amplificação de Ácido Nucleico/métodos , Carbocianinas/química , Complexos de Coordenação/química , Limite de Detecção , Sensibilidade e Especificidade , Térbio/química
17.
Chemistry ; 24(46): 11885-11889, 2018 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-29939467

RESUMO

Lanthanide(III) ions bind to the glycocalyx of Chinese Hamster Ovary (CHO) cells and give rise to a unique luminescent fingerprint. Following direct excitation of terbium(III) and europium(III) ions in the visible part of the spectrum, we are able to collect emission spectra pixel-by-pixel in images of CHO cells. Following data analysis that removes the background signal, the fine structure of the europium(III) luminescence indicate that the lanthanide(III) ions are bound to a single structure of the CHO cell glycocalyx. This was deduced from the fact that the structure-sensitive emission spectrum of europium is unchanged throughout the investigated samples.


Assuntos
Európio/química , Elementos da Série dos Lantanídeos/química , Luminescência , Térbio/química , Animais , Células CHO , Cricetinae , Cricetulus , Íons
18.
Spectrochim Acta A Mol Biomol Spectrosc ; 203: 461-471, 2018 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-29894961

RESUMO

In this study, a novel fluorescent probe, TbIII-dtpa-bis(2,6-diaminopurine) (Tb-dtpa-bdap), is designed based on the principle of complementary base pairing and synthesized for uric acid detection. The synthesized fluorescent probe is characterized by 1H NMR, 13C NMR, infra-red (IR) spectrum and ultraviolet-visible (UV-vis) spectra. It is found that the fluorescence of Tb-dtpa-bdap solution can be quenched obviously in the presence of uric acid. The affecting factors, including solution acidity, uric acid concentration and interfering substances, on the detection of uric acid using this probe are examined. Under optimized conditions, the fluorescence intensities of Tb-dtpa-bdap solution towards different uric acid concentrations show a linear response in the range from 1.00 × 10-5 mol·L-1 to 5.00 × 10-5 mol·L-1 with a linear correlation coefficient (R2) of 0.9877. And the obtained limit of detection (LOD) is about 5.80 × 10-6 mol·L-1, which is lower than the level of uric acid in actual urine. The mechanism on the detection of uric acid by using Tb-dtpa-bdap is inferred from the experimental results. The facts demonstrate that the proposed fluorescent probe can be successfully applied for the determination of uric acid in human urine samples.


Assuntos
2-Aminopurina/análogos & derivados , Corantes Fluorescentes/química , Corantes Fluorescentes/síntese química , Ácido Pentético/química , Térbio/química , Ácido Úrico/urina , 2-Aminopurina/química , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Humanos , Concentração de Íons de Hidrogênio , Espectroscopia de Prótons por Ressonância Magnética , Soluções , Espectrometria de Fluorescência , Espectroscopia de Infravermelho com Transformada de Fourier
19.
Talanta ; 186: 97-103, 2018 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-29784425

RESUMO

Zearalenone (ZEN) is a non-steroidal estrogenic mycotoxin produced by fungi on stored grains. The earlier detection methods used for ZEN rely on expensive equipment, time-consuming sample preparation and temperature sensitive antibodies. The current work, proposed a novel strategy based on ZEN aptamer labeled with amine-functionalized magnetic nanoparticle (MNPs) as a capture probe and time-resolved fluorescence (TRFL) nanoparticles labeled with complementary DNA (cDNA) as a signal probe. Under the optimized conditions, TRFL intensity at 544 nm was used to measure ZEN (R2 = 0.9920) in the range of 0.001-10 ng mL-1 and limits of detection (LOD) for proposed method was 0.21 pg mL-1. The specificity of bioassay was also determined by using other mycotoxins (OTA, AFB2, DON and Patulin) and results showed that the aptamer are specific to recognize only ZEN. The analytical applications of the present bioassay in maize and wheat samples were also examined and results were compared with existing methods. Based on these findings, it is suggested to use current rapid and simple bioassay for the determination of ZEN in food and agricultural products.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais , Corantes Fluorescentes/química , Contaminação de Alimentos/análise , Nanopartículas de Magnetita/química , Zearalenona/análise , Cério/química , Fluorescência , Corantes Fluorescentes/síntese química , Fluoretos/química , Nanopartículas/química , Tamanho da Partícula , Propriedades de Superfície , Térbio/química , Fatores de Tempo , Triticum/química , Ítrio/química , Zea mays/química
20.
Chemistry ; 24(39): 9739-9746, 2018 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-29806881

RESUMO

Crystallophores are lanthanide complexes that act as powerful auxiliary for protein crystallography due to their strong nucleating and phasing effects. To get first insights on the mechanisms behind nucleation induced by Crystallophore, we systematically identified various elaborated networks of supramolecular interactions between Tb-Xo4 and subset of 6 protein structures determined by X-ray diffraction in complex with terbium-Crystallophore (Tb-Xo4). Such interaction mapping analyses demonstrate the versatile binding behavior of the Crystallophore and pave the way to a better understanding of its unique properties.


Assuntos
Elementos da Série dos Lantanídeos/química , Proteínas/química , Térbio/química , Cristalografia por Raios X
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