Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 4.085
Filtrar
Filtros adicionais











Intervalo de ano
1.
Chem Commun (Camb) ; 55(72): 10713-10716, 2019 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-31429427

RESUMO

A red light-triggered reaction based on cyclic oligonucleotide substrates that is accelerated over 30-fold by specific nucleic acid templates and generates a bright fluorescent probe was developed. We confirmed that this reaction is compatible with fluorescence correlation spectroscopy (FCS) thereby allowing detection of nucleic acids down to 1 nM.


Assuntos
Luz , Ácidos Nucleicos/análise , Oligonucleotídeos/química , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/química , Estrutura Molecular , Espectrometria de Fluorescência
2.
Chem Commun (Camb) ; 55(68): 10128-10131, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31386708

RESUMO

Fueled by the therapeutic potential of the epigenetic machinery, BET bromodomains have seen high interest as drug targets. Herein, we introduce different linkers to a BET bromodomain benzodiazepine ligand (I-BET762) to gauge its implications in the development of hybrid drugs, imaging probes and small molecule drug conjugates. Biophysical studies confirmed minimal disruption to binding of the BRD4 cavity by the synthesized entities, which includes imaging probes. Target engagement was confirmed in a cellular context, but poor membrane diffusion was found despite efficient localization in the nuclei after membrane disruption. Our study highlights challenges and opportunities for the successful design of benzodiazepine-derived drug-delivery systems.


Assuntos
Benzodiazepinas/farmacologia , Fluoresceínas/farmacologia , Corantes Fluorescentes/farmacologia , Proteínas Nucleares/antagonistas & inibidores , Benzodiazepinas/síntese química , Benzodiazepinas/química , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Desenho de Drogas , Fluoresceínas/síntese química , Fluoresceínas/química , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/química , Humanos , Ligantes , Estrutura Molecular , Proteínas Nucleares/química , Domínios Proteicos
4.
Chem Commun (Camb) ; 55(71): 10627-10630, 2019 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-31429450

RESUMO

We report the synthesis of a novel hydroxyl-functionalised heteroleptic bis-NHC gold(i) complex that permits conjugation to various amines via carbamate bond formation. The resulting derivatives were studied in vitro using cell proliferation assays and fluorescent microscopic imaging of human cancer cell lines.


Assuntos
Aminas/química , Antineoplásicos/síntese química , Carbamatos/química , Complexos de Coordenação/síntese química , Corantes Fluorescentes/síntese química , Ouro/química , Células A549 , Antineoplásicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Complexos de Coordenação/farmacologia , Doxorrubicina/química , Humanos , Imagem Óptica , Tiorredoxina Dissulfeto Redutase/antagonistas & inibidores , Triazóis/química
5.
Anal Chim Acta ; 1078: 135-141, 2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31358211

RESUMO

Hypochlorous acid (HOCl)/hypochlorite (OCl-), important reactive oxygen species, play essential roles in many physiological and pathological progresses. Accordingly, we developed a novel dicyanomethylene-4H-pyran (DCM)-based probe DCM-OCl for colorimetric and near-infrared fluorescent turn-on detection of OCl-. The probe exhibited excellent selectivity and sensitivity for OCl- over other bio-related analytes with a detection limit of 80 nM. The excellent selectivity of DCM-OCl for OCl- was ascribed to specific oxidative cleavage of the dimethylthiocarbamate (DMTC) recognition unit by OCl-. Moreover, DCM-OCl exhibited an ultrafast turn-on response (<3 s) to OCl-, potentially allowing real-time detection of OCl-. Furthermore, DCM-OCl was successfully used to image endogenous/exogenous OCl- in living cells.


Assuntos
Benzopiranos/química , Corantes Fluorescentes/química , Ácido Hipocloroso/análise , Tiocarbamatos/química , Benzopiranos/síntese química , Benzopiranos/toxicidade , Colorimetria/métodos , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/toxicidade , Células HeLa , Humanos , Limite de Detecção , Tiocarbamatos/síntese química , Tiocarbamatos/toxicidade
6.
Photochem Photobiol Sci ; 18(8): 1972-1981, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31259994

RESUMO

Betalains are natural plant pigments found in certain plants belonging to the order Caryophyllales. This work presents theoretical calculations on the excited state properties of three betalains: betanin, an almost non-fluorescent natural betacyanin; indicaxanthin, a weakly fluorescent natural betaxanthin; and cBeet120, a synthetic betaxanthin fluorescence probe that is also weakly fluorescent. Calculations at the algebraic diagrammatic construction (ADC (2)) level of theory, combined with the conductor-like screening model (COSMO) to simulate solvent effects, predict absorption spectra in good agreement with experiment for all three of these betalains. Several distinct theoretical approaches identify torsions of the molecular geometry that can lead to conical intersections between the excited singlet (S1) and ground state (S0) potential surfaces and identify probable geometries at the minimum on the crossing seam (MXS). The present results thus emphasize the central role played by torsional modes in determining the fluorescence properties of natural betalains and of most synthetic betalain analogs as well. A direct implication of the results is that the fluorescence quantum yields of natural or synthetic betalains can potentially be enhanced by introducing structural modifications that permit the molecule to avoid these MXS geometries and/or by incorporation into a more rigid environment that hinders the specific bond rotations involved in the non-radiative relaxation of the excited state.


Assuntos
Betalaínas/química , Fluorescência , Corantes Fluorescentes/química , Betalaínas/síntese química , Caryophyllales/química , Teoria da Densidade Funcional , Corantes Fluorescentes/síntese química , Conformação Molecular
8.
Chem Commun (Camb) ; 55(65): 9629-9632, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31353368

RESUMO

Excessive accumulation of reducing agents in the ER leads to a constitutively high UPR. And the co-function of GSH, Cys and HOCl in biological processes is not well understood. To address this, a TP probe, NPCC, was developed for monitoring reductive stress in the ER. It can also distinguish cancer cells from normal cells.


Assuntos
Cumarínicos/química , Estresse do Retículo Endoplasmático/fisiologia , Retículo Endoplasmático/metabolismo , Corantes Fluorescentes/química , Pirazóis/química , Animais , Cumarínicos/síntese química , Cisteína/química , Cisteína/metabolismo , Corantes Fluorescentes/síntese química , Glutationa/química , Glutationa/metabolismo , Cabras , Células HeLa , Humanos , Ácido Hipocloroso/química , Ácido Hipocloroso/metabolismo , Camundongos , Microscopia Confocal/métodos , Microscopia de Fluorescência/métodos , Oxirredução , Pirazóis/síntese química , Peixe-Zebra
9.
Inorg Chem ; 58(15): 9956-9963, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31290308

RESUMO

The research on luminescent lanthanide-functionalized covalent organic framework (COF)-based hybrid materials has not been reported so far. When a straightforward functionalized modification strategy is employed, a chemical stable Eu3+-modified COF hybrid material, Eu@TpPa-1, is first developed. The functional process does not affect the size and shape of TpPa-1, but after the introduction of Eu3+, Eu@TpPa-1 as a fluorescence sensor exhibits a turn-on response toward levofloxacin. Eu3+ plays a bridge role in the whole detection system, and TpPa-1 serves as a host matrix to provide protection for the introduced Eu3+. This reusable sensor shows strong pink-white and yellow emissions toward the high and low concentration ranges of levofloxacin, respectively. It displays excellent sensitivity and fast response to levofloxacin within 1 min, while refraining from the interference of other coexisting species in serum and urine. The good selectivity and high antidisturbance lead Eu@TpPa-1 to be successfully applied in serum and urine systems for sensing levofloxacin.


Assuntos
Európio/química , Fluorescência , Levofloxacino/sangue , Levofloxacino/urina , Estruturas Metalorgânicas/química , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/química , Humanos , Medições Luminescentes , Estruturas Metalorgânicas/síntese química
10.
Chem Commun (Camb) ; 55(67): 9919-9922, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31328197

RESUMO

Reported herein is a relebactam-derived fluorogenic reagent for covalent labeling of serine ß-lactamases (SBLs), which are the major causes of bacterial resistance to ß-lactam antibiotics. This highly selective imaging reagent generates over 300-fold stronger near-infrared fluorescence signals upon covalently bonding to SBLs, allowing wash-free visualization of live antimicrobial-resistant bacteria.


Assuntos
Marcadores de Afinidade/farmacologia , Compostos Azabicíclicos/farmacologia , Enterobacter cloacae/isolamento & purificação , Corantes Fluorescentes/farmacologia , Inibidores de beta-Lactamases/farmacologia , beta-Lactamases/química , Marcadores de Afinidade/síntese química , Marcadores de Afinidade/química , Compostos Azabicíclicos/síntese química , Compostos Azabicíclicos/química , Enterobacter cloacae/enzimologia , Fluoresceínas/síntese química , Fluoresceínas/química , Fluoresceínas/farmacologia , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/química , Indóis/síntese química , Indóis/química , Indóis/farmacologia , Inibidores de beta-Lactamases/síntese química , Inibidores de beta-Lactamases/química
11.
Chem Commun (Camb) ; 55(59): 8564-8566, 2019 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-31271158

RESUMO

Diphenylalanine (FF), as the smallest unit and core recognition motif of ß-amyloid (Aß), could self-assemble into nanofibers, which induces an early onset of Alzheimer's disease (AD). Green/near-infrared fluorescent BODIPY probes were designed and synthesized to detect FF-assembly, providing unique insights into the chemical and molecular mechanism of Aß aggregation and drug development for AD.


Assuntos
Compostos de Boro/química , Corantes Fluorescentes/química , Fenilalanina/análogos & derivados , Técnicas Biossensoriais/métodos , Compostos de Boro/síntese química , Corantes Fluorescentes/síntese química , Nanofibras/química , Fenilalanina/análise , Fenilalanina/química , Multimerização Proteica
12.
Chem Commun (Camb) ; 55(58): 8494-8497, 2019 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-31268095

RESUMO

A rational strategy was reported to construct boranil complexes (DPFB derivatives) with unique aggregation-induced emission effects by installing phenyl rings in the anil ligand as the intramolecular rotors. In view of the good biocompatibility and suitable lipophilicity, DPFB derivatives can serve as excellent fluorescent probes for specific imaging of lipid droplets in living cells and yolk lipids in zebrafish.


Assuntos
Compostos de Anilina/química , Compostos de Boro/química , Complexos de Coordenação/química , Corantes Fluorescentes/química , Gotículas Lipídicas/metabolismo , Compostos de Anilina/síntese química , Animais , Compostos de Boro/síntese química , Complexos de Coordenação/síntese química , Fluorescência , Corantes Fluorescentes/síntese química , Células HeLa , Humanos , Ligantes , Microscopia Confocal/métodos , Estrutura Molecular , Peixe-Zebra
13.
Chem Commun (Camb) ; 55(65): 9649-9652, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31339160

RESUMO

Intracellular delivery of bioactive polyphenols is currently evaluated as a protective strategy for cells under pharmaceutical stress. To this end, the 20mer R5 peptide from the marine diatom C. fusiformis was N-terminally modified with a quercetin derivative. This polyphenol-peptide conjugate was used to generate homogeneous silica particles under biomimetic conditions that are efficiently taken up by eukaryotic cells without being cytotoxic. However, not only was accumulation in the cytoplasm of living cells observed via electron and fluorescence microscopy but also translocation into the nucleus. The latter was only seen when the quercetin-peptide conjugate was present within the silica particles and provides a novel targeting option for silica particles to nuclei.


Assuntos
Núcleo Celular/metabolismo , Corantes Fluorescentes/farmacocinética , Fragmentos de Peptídeos/farmacocinética , Quercetina/análogos & derivados , Quercetina/farmacocinética , Dióxido de Silício/farmacocinética , Transporte Ativo do Núcleo Celular , Biomimética , Diatomáceas/química , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/química , Corantes Fluorescentes/toxicidade , Células HT29 , Humanos , Fragmentos de Peptídeos/síntese química , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/toxicidade , Quercetina/síntese química , Quercetina/toxicidade , Dióxido de Silício/química , Dióxido de Silício/toxicidade
14.
Analyst ; 144(16): 4908-4916, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31312834

RESUMO

A new benzothiazole azo dye [(E)-1-((6-methoxybenzo[d]thiazole-2-yl)diazenyl)naphthalene-2,6-diol] (also known as "BAN"), has been synthesised and used as a chemosensor for the rapid and selective detection of mercury(ii) ions in water. The pink coloured chemosensor turns blue when reacted with mercury(ii) ions due to the formation of a 2 : 1 coordination complex. The complex formation causes a bathochromic shift of the chemosensor's UV absorption peak from 540 to 585 nm and turns on a highly selective fluorescence emission at 425 nm. The change in the optical property of BAN upon complexation with mercury(ii) was confirmed by ab initio calculations. The new chemosensor was used to quantify mercury(ii) ions in water by fluorescence spectroscopy down to 5 × 10-8 M (10 ppb). The limit of detection (LOD) of Hg2+ was 9.45 nM (1.8 ppb) which satisfies the maximum allowable Hg2+ concentration in drinking water that is set by the WHO. The BAN-Hg(ii) complex was used for the determination of cysteine (Cys) in aqueous solution by UV-Vis spectroscopy down to 1 × 10-7 M. The thiol-containing amino acid preferentially coordinates the mercury ions of the BAN-Hg(ii) complex. This causes dissociation of the blue-coloured complex and the liberation of the pink-coloured BAN dye. The colour change of the BAN-Hg(ii) complex from blue to pink was selective to the Cys biothiol while other non-thiol containing amino acids did not cause a colour change. For the in-field application, filter paper strips were loaded with the BAN-Hg(ii) complex and used as a disposable sensor for the detection of cysteine (Cys) by the naked eye. Therefore, the BAN chemosensor offers a sensitive, and rapid tool for the detection of mercury(ii) in water. In addition, the BAN-Hg(ii) complex can be used as a simple and selective chemosensor of the screening of purified biothiols, such cysetine, homocysteine and glutathione in biology research and pharmaceutical/food industries.


Assuntos
Benzotiazóis/síntese química , Corantes Fluorescentes/síntese química , Mercúrio/análise , Compostos de Sulfidrila/análise , Poluentes Químicos da Água/análise , Cátions Bivalentes , Cor , Simulação por Computador , Complexos de Coordenação/química , Cisteína/análise , Teoria da Densidade Funcional , Glutationa/análise , Concentração de Íons de Hidrogênio , Ligantes , Limite de Detecção , Espectrometria de Fluorescência
15.
Eur J Med Chem ; 178: 458-467, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31202993

RESUMO

The liver X receptors (LXRs) of the nuclear receptor family are promising therapeutic targets of multiple diseases like lipid disorders, chronic inflammation, as well as different human cancers. To date, no LXR agonists or antagonists can be used in clinics, emphasizing the importance for discovering new LXR modulators. Fragment-based lead discovery (FBLD) is powerful for designing new scaffolds and new mechanistic drugs, but fragment screening has not been applied to LXRs yet, which might be due to the lack of a specific fragment screening method against the dynamic and hydrophobic ligand binding domain (LBD) of LXRs. Herein, a series of fluorescent tracers were designed, synthesized and tested. The tracer based on hyodeoxycholic acid exhibited a good capability for competitively detecting the ligand binding of LXRß using a fluorescence polarization approach. Then, 1074 fragments were screened against the LBD of LXRß (LXRß-LBD), resulting in 27 binding hits. These fragment hits were further tested using the co-activator recruitment assay and reporter gene assay, and efforts in X-ray crystallography fortunately solved a co-crystal structure of LXRß-LBD with the fragment F3 (tert-butyl-7-amino-3,4-dihydroisoquinoline-2(1H)-carboxylate). The fluorescence-based fragment screening tool and the newly identified LXRß binding fragments provide the basis for developing novel LXRß modulators.


Assuntos
Ácido Desoxicólico/farmacologia , Polarização de Fluorescência , Corantes Fluorescentes/farmacologia , Receptores X do Fígado/antagonistas & inibidores , Cristalografia por Raios X , Ácido Desoxicólico/síntese química , Ácido Desoxicólico/química , Relação Dose-Resposta a Droga , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/química , Humanos , Receptores X do Fígado/metabolismo , Modelos Moleculares , Estrutura Molecular , Relação Estrutura-Atividade
16.
Chem Commun (Camb) ; 55(54): 7776-7779, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31210218

RESUMO

An unusual class, compact in size, of fluorescent probes based on pyridazino-1,3a,6a-triazapentalene scaffolds exhibits promising fluorescent properties (quantum yield values up to 73%, large Stokes shifts, emission wavelengths located in the green-yellow range, excellent solubility) with good photostability suitable for optical imaging applications.


Assuntos
Corantes Fluorescentes/química , Compostos Heterocíclicos com 3 Anéis/química , Fluorescência , Corantes Fluorescentes/síntese química , Células HeLa , Compostos Heterocíclicos com 3 Anéis/síntese química , Humanos , Microscopia de Fluorescência/métodos , Imagem Óptica/métodos , Fotodegradação
17.
Chem Commun (Camb) ; 55(54): 7852-7855, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31215553
18.
Inorg Chem ; 58(13): 8369-8378, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31247863

RESUMO

This article reports the effect of Gd(III) doping on the structure, microstructure, and optical properties of boehmite nanoparticles. The bright-blue fluorescence along with a long lifetime makes our material an efficient candidate for optical applications. Our material particularly targets and eliminates hexavalent chromium ions (Cr(VI)) from aqueous media, which turns it into a multifunctional fluorescent nanosensor (MFNS). The development of an efficient hexavalent chromium ion (Cr(VI)) sensor to detect and quantify Cr(VI) ions is still a serious issue worldwide. Thus, this work will be very beneficial for various environmental applications. No such work has been reported so far which includes cost-effective and biocompatible boehmite nanoparticles in this field. Detailed synthesis and characterization procedures for the MFNS have been incorporated here. The biocompatibility of the MFNS has also been studied rigorously by performing cell survivability assay (MTT) and cellular morphology assessments. Our extensive research confirmed that the "turn-off" sensing mechanism of this sensor material is based on a collisional quenching model which initiates the photoinduced electron transfer (PET) process. High selectivity and sensitivity (∼1.05 × 10-5 M) of the MFNS toward hexavalent chromium ions even in real life wastewater samples have been confirmed, which makes this fluorescent probe a potential candidate for new age imaging and sensing technologies.


Assuntos
Hidróxido de Alumínio/química , Óxido de Alumínio/química , Cromo/análise , Corantes Fluorescentes/química , Nanopartículas/química , Águas Residuárias/análise , Adsorção , Hidróxido de Alumínio/síntese química , Óxido de Alumínio/síntese química , Linhagem Celular Tumoral , Fluorescência , Corantes Fluorescentes/síntese química , Gadolínio/química , Humanos , Limite de Detecção , Microscopia de Fluorescência/métodos , Porosidade , Espectrometria de Fluorescência/métodos
19.
Chem Commun (Camb) ; 55(53): 7691-7694, 2019 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-31204742

RESUMO

We reported two simple rhodamine-based colourimetric sensors for the first time which can selectively and sensitively detect salicylic acid (SA) under naked-eye detection. We proposed two distinctly different modes to elucidate the possible mechanism for monitoring SA. The rationally designed probes can be well exploited in signalling SA in living cell lines.


Assuntos
Corantes Fluorescentes/química , Imagem Óptica , Rodaminas/química , Ácido Salicílico/análise , Corantes Fluorescentes/síntese química , Estrutura Molecular , Rodaminas/síntese química
20.
Chem Commun (Camb) ; 55(60): 8860-8863, 2019 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-31219109

RESUMO

We report the first dual-responsive 19F MRI and fluorescence imaging probe for cellular hypoxia. The Cu2+-based probe exhibits no 19F MR signal and reduced fluorescence signal due to paramagnetic quenching; however, the probe turns-on in both modes following reduction to Cu+. This bimodal agent can differentiate hypoxic and normoxic cells in both modalities.


Assuntos
Hipóxia Celular/fisiologia , Complexos de Coordenação/química , Fluoresceínas/química , Corantes Fluorescentes/química , Complexos de Coordenação/síntese química , Complexos de Coordenação/toxicidade , Cobre/química , Fluoresceínas/síntese química , Fluoresceínas/toxicidade , Fluorescência , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/toxicidade , Flúor , Imagem por Ressonância Magnética de Flúor-19/métodos , Células HeLa , Humanos , Concentração de Íons de Hidrogênio , Microscopia de Fluorescência/métodos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA