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1.
Inorg Chem ; 58(19): 12700-12706, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31556291

RESUMO

The highly porous luminescent metal-organic frameworks (MOFs) can act as fluorescent probes for the detection of nitro compounds and can also serve as containers and energy transfer platforms to construct the host-guest systems. Herein, two new three-dimensional MOFs with high porosity were prepared successfully by the electron-rich tetrakis(4-pyridylphenyl)ethylene (tppe) as ligands. Compound 1 shows the high sensitivity and selectivity toward nitro-antibiotics in an aqueous media, particularly showing the best detection efficiency for furazolidone (FZD) among the reported luminescent sensors. The highly efficient fluorescence quenching toward FZD may be attributed to the electron and energy transfer. Compound 2 has naphthalene-2,7-dicarboxylic acid (2,7-npd) and tppe as dual linkers, and the energy transfer between 2,7-npd and tppe leads to the emission band in a large scale. It is worth noting that the single-phased white-light materials can be obtained by the in situ encapsulation of different concentration of sulforhodamine 101 (SR101) into compound 2 matrix.


Assuntos
Antibacterianos/análise , Substâncias Luminescentes/química , Estruturas Metalorgânicas/química , Nitrocompostos/análise , Estilbenos/química , Cristalografia por Raios X , Luminescência , Medições Luminescentes , Modelos Moleculares , Rodaminas/química
2.
J Agric Food Chem ; 67(38): 10726-10733, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31469953

RESUMO

A turn-on fluorescent probe, HOCD-RB, for monitoring singlet oxygen (1O2) was developed by linking rhodamine B as fluorophore with dimethylhomoocoerdianthrone (HOCD) as 1O2 reaction site and fluorescence quencher due to the intramolecular energy transfer (ET) between rhodamine B and HOCD moieties. Upon exposure to 1O2 it rapidly forms endoperoxide with HOCD and turns on the fluorescence of rhodamine B by 18-fold. Taking advantage of the HOCD-RB probe that shows fast response, high sensitivity, and selectivity for 1O2, it is applied for imaging of endogenous 1O2 in living cells and the fluorometric assay for evaluating 1O2 quenching activity of selected common flavonoids found in our daily diets. The results show that the 1O2 scavenging activity of flavonoids depends on not only the structure of individual flavonoid but also the competitive interactions between mixed flavonoids. The best antioxidant capacity for individual and mixed flavonoids is epigallocatechin gallate and the mixture of catechin gallate with kaempferol, respectively. Overall, this work provided a new tool for detection and imaging of singlet oxygen activity in a biological system as well as an efficient fluorometric assay of 1O2 scavenging activity.


Assuntos
Flavonoides/química , Corantes Fluorescentes/química , Fluorometria/métodos , Depuradores de Radicais Livres/química , Rodaminas/química , Oxigênio Singlete/química , Fluorescência , Estrutura Molecular
3.
Chem Commun (Camb) ; 55(73): 10916-10919, 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31441466
4.
Water Sci Technol ; 80(1): 109-116, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31461427

RESUMO

Due to the high Brunauer-Emmett-Teller (BET) surface area of zeolitic imidazolate framework (ZIF)-8, a secondary crystallization method was used to prepare a particle electrode of γ-Al2O3@ZIF-8. According to the results from a field emission scanning electron microscope (SEM) and X-ray diffractometer (XRD), the particle electrode of γ-Al2O3 was successfully loaded with ZIF-8, and the BET surface area (1,433 m2/g) of ZIF-8 was over ten times that of γ-Al2O3. The key operation parameters of cell voltage, pH, initial RhB concentration and electrolyte concentration were all optimized. The observed rate constant (kobs) of the pseudo-first-order kinetic model for the electrocatalytic oxidation (ECO) system with the particle electrode of γ-Al2O3@ZIF-8 (15.2 × 10-2 min-1) was over five times higher than that of the system with the traditional particle electrode of γ-Al2O3 (2.6 × 10-2 min-1). The loading of ZIF-8 on the surface of γ-Al2O3 played an important role in improving electrocatalytic activity for the degradation of Rhodamine B (RhB), and the RhB removal efficiency of the three-dimensional (3D) electrocatalytic system with the particle electrode of γ-Al2O3@ZIF-8 was 93.5% in 15 min, compared with 27.5% in 15 min for the particle electrode of γ-Al2O3. The RhB removal efficiency was kept over 85% after five cycles of reuse for the 3D electrocatalytic system with the particle electrode of γ-Al2O3@ZIF-8.


Assuntos
Eletrodos , Rodaminas/química , Zeolitas , Oxirredução , Rodaminas/análise , Eliminação de Resíduos Líquidos
5.
Fish Shellfish Immunol ; 92: 871-880, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31299464

RESUMO

The neutrophil oxidative respiratory burst response is a key component of the innate immune system responsible for killing microbial pathogens. Since fish rely on the innate immune system for health, monitoring the respiratory burst activity may be an effective means of gauging fish health status. Here we report that the respiratory burst of Asian seabass neutrophils can be measured in whole blood by the dihydrorhodamine (DHR)-123 reduction assay and flow cytometry. Neutrophils responded to phorbol myristate acetate (PMA) in a concentration dependent manner with significant respiratory burst activity at 100-1000 nM. Other known neutrophil agonists, such as bacterial lipopolysaccharide, tumor necrosis factor, the tripeptide f-met-leu-phe and zymosan, did not induce a significant DHR reduction. Thus, the findings enable us to propose that the DHR-123 flow cytometry whole blood assay, incorporating PMA as a stimulator, would not only facilitate future studies into fish blood neutrophil research but provides a simple, rapid and reliable assay for gauging fish natural immunity status and health.


Assuntos
Bass/fisiologia , Citometria de Fluxo/veterinária , Imunidade Inata , Neutrófilos/fisiologia , Explosão Respiratória/fisiologia , Animais , Citometria de Fluxo/métodos , Oxirredução , Rodaminas/química
6.
Environ Sci Pollut Res Int ; 26(25): 26389-26396, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31292864

RESUMO

Silver nanoparticles in carbon nanotubes (AgNPs-in-CNTs) were prepared through a simple thermal decomposition method. Synthesized AgNPs-in-CNTs were characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy, high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS). In the presence of hydrogen peroxide (H2O2), AgNPs-in-CNTs exhibited perfect photocatalytic activity in rhodamine B (RhB) degradation under visible light irradiation. Hydrogen peroxide (H2O2) concentration and initial pH values were comprehensively scrutinized. When the concentration of H2O2 was 20 mM, about 99.8% RhB (20 mg L-1) could be degraded within 50 min while the initial pH (3-10) values had a negligible effect on the degradation. From the investigations of Raman spectroscopy, transient photocurrent responses, photoluminescence, and radical quenching experiments, the findings suggest that under light irradiation, AgNPs-in-CNTs can absorb photons and generate photogenerated electrons through localized surface plasmon resonance (LSPR) effect, the photogenerated electrons react with H2O2 to produce ·OH radicals for decomposing RhB.


Assuntos
Peróxido de Hidrogênio/química , Nanopartículas Metálicas/química , Nanotubos de Carbono/química , Prata/química , Catálise , Elétrons , Corantes Fluorescentes/química , Luz , Microscopia Eletrônica de Transmissão , Processos Fotoquímicos , Espectroscopia Fotoeletrônica , Rodaminas/química , Análise Espectral Raman , Ressonância de Plasmônio de Superfície , Difração de Raios X
7.
Eur J Pharm Biopharm ; 142: 480-487, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31336183

RESUMO

Novel fluorescently labeled poly(ethylene glycol)-poly(hydroxyoctanoic acid) (MPEG-PHOA) block-copolymers were synthesized for the improved visualization of the deriving polymeric micelle drug delivery system. Albeit commonly used, one has to be aware that by simple incorporation of Nile Red (hydrophobic) or Rhodamine B (hydrophilic) as fluorescent compounds in nanocarriers (e.g., nanoparticles, liposomes or micelles) for imaging applications, these fluorescent probes can diffuse out of the carrier system and lead to artefacts due to the concomitant fluorescence loss or areal distribution. In order to inhibit such an uncontrolled diffusion, the Nile Red derivative 2-((9-(diethylamino)-5-oxo-5H-benzo[a]phenoxazin-2-yl)oxy)acetic acid was synthesized and covalently attached to the MPEG-PHOA block-copolymer via a mild Mitsunobu reaction to yield the desired MPEG-PHOA-Nile Red polymer for micelle preparations. Rhodamine B was coupled via its native carboxylic acid group with the copolymer MPEG-PHOA under mild conditions using DMAP, EDC, and NHS. For the proof of concept, aqueous solutions of composite micelles made of 0.5% (w/w fluorescence dye) MPEG-PHOA-dye and MPEG-PHOA copolymers were prepared ("spiking" of the non-labeled base MPEG-PHOA micelles) and characterized by transmission electron microscopy (TEM), dialysis and fluorescence spectrometry. The fluorescence intensity of the Nile Red in the solutions was followed up at physiological temperatures and pH values (37 °C, pH = 7.4 PBS buffer 0.01 M) over a period of 8 weeks. The labeled and non-labeled micelle formulations were tested in vitro in cells (Rhodamine-micelle formulations), then in vivo in a case study of an ophthalmic application (Nile Red micelle formulations). Both in vitro and in vivo experiments revealed a significant improvement of fluorescence stability of the MPEG-PHOA-dye formulations, facilitating the investigations on tracing the micelles and their stability. The results clearly demonstrate the value of the novel Nile Red and Rhodamine derivatives, whose simple synthesis and covalent attachment may easily be transferred to other nanosized polymeric drug delivery systems, e.g., MPEGylated or non-MPEGylated PLA/PLGA nanoparticles and be envisioned for novel theranostic systems.


Assuntos
Corantes Fluorescentes/química , Oxazinas/química , Polímeros/química , Rodaminas/química , Portadores de Fármacos/química , Composição de Medicamentos/métodos , Sistemas de Liberação de Medicamentos/métodos , Interações Hidrofóbicas e Hidrofílicas , Micelas , Polietilenoglicóis/química , Água/química
8.
Environ Sci Pollut Res Int ; 26(26): 27063-27072, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31313234

RESUMO

In this study, a sensitive and low-cost multi-wavelength spectrophotometric method for the determination of hydrogen peroxide (H2O2) in water was established. The method was based on the oxidative coloration of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) via Fenton reaction, which resulted in the formation of green radical (ABTS•+) with absorbance at four different wavelengths (i.e., 415 nm, 650 nm, 732 nm, and 820 nm). Under the optimized conditions (CABTS = 2.0 mM, CFe2+ = 1.0 mM, pH = 2.60 ± 0.02, and reaction time (t) = 1 min), the absorbance of the generated ABTS•+ at 415 nm, 650 nm, 732 nm, and 820 nm were well linear with H2O2 concentrations in the range of 0-40 µM (R2 > 0.999) and the sensitivities of the proposed Fenton-ABTS method were calculated as 4.19 × 104 M-1 cm-1,1.73 × 104 M-1 cm-1, 2.18 × 104 M-1 cm-1, and 1.96 × 104 M-1 cm-1, respectively. Meanwhile, the detection limits of the Fenton-ABTS method at 415 nm, 650 nm, 732 nm, and 820 nm were respectively calculated to be 0.18 µM, 0.12 µM, 0.10 µM, and 0.11 µM. The absorbance of the generated ABTS•+ in ultrapure water, underground water, and reservoir water was quite stable within 30 min. Moreover, the proposed Fenton-ABTS method could be used for monitoring the variations of H2O2 concentration during the oxidative decolorization of RhB in alkali-activated H2O2 system.


Assuntos
Benzotiazóis/química , Peróxido de Hidrogênio/análise , Espectrofotometria/métodos , Ácidos Sulfônicos/química , Água/análise , Cor , Corantes Fluorescentes/química , Água Doce/análise , Peróxido de Hidrogênio/química , Concentração de Íons de Hidrogênio , Ferro/química , Limite de Detecção , Oxirredução , Rodaminas/química , Água/química
9.
Anal Chim Acta ; 1077: 243-248, 2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31307715

RESUMO

A novel imidazo[1,2-a]pyridine-rhodamine ratiometric fluorescent probe IP-Hg for Hg2+ based on a fluorescence resonance energy transfer mechanism has been developed. The probe has been proved to show high sensitivity and high selectivity toward Hg2+. Furthermore, it could be used for imaging Hg2+ in cells and in polluted water.


Assuntos
Corantes Fluorescentes/química , Imidazóis/química , Mercúrio/análise , Piridinas/química , Rodaminas/química , Poluentes Químicos da Água/análise , Transferência Ressonante de Energia de Fluorescência/métodos , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/toxicidade , Imidazóis/síntese química , Imidazóis/toxicidade , Lagos/análise , Limite de Detecção , Piridinas/síntese química , Piridinas/toxicidade , Rodaminas/síntese química , Rodaminas/toxicidade , Células Tumorais Cultivadas
10.
Phys Chem Chem Phys ; 21(31): 17163-17169, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31342023

RESUMO

Two-dimensional (2D) heteromaterials with large interface contact and intimate interfacial charge transition have been considered to be an ideal model for constructing highly efficient photocatalysts. However, few studies have reported on these 2D heterojunctions. Herein, we report a series of new 2D heterojunctions comprising polyimide (PI) and perylene-3,4,9,10-tetracarboxylic dianhydride (TD). These heterojunctions, denoted as PI-TDx (where x represents the amount of TD added, i.e., x = 0.13, 0.18, 0.27, 0.54, and 1.08 g), were prepared by the solid thermal copolymerization of melamine (MA), pyromellitic dianhydride (PD), and different amounts of TD. FT-IR spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy analyses were used to verify the 2D heterojunction structure. Photocatalytic experiments reveal that PI-TDx exhibit excellent and stable photocatalytic performance for the degradation of the organic dyes rhodamine B (RhB) and methyl violet (MV), as well as for the photoreduction of Cr(vi), under visible-light irradiation. Among the samples, PI-TD0.18 exhibits the best photocatalytic performance. Its activity is about 2.7 times and 7.5 times higher than that of individual PIMP (formed by MA and PD) and PIMT (formed by MA and TD) for RhB degradation, respectively. Notably, PI-TD0.18 retains a certain photocatalytic activity under light irradiation at 600 nm. The photocatalytic-mechanism study demonstrates that PI-TD0.18 has a classic type-II heterojunction. Its 2D heterojunction greatly enhances the visible-light absorption of the composites and effectively suppresses the radiation recombination of photogenerated carriers, thereby improving its charge transfer and separation abilities and providing excellent photocatalytic performance. This work may serve as an important reference for the design and construction of new highly efficient 2D organic conjugated-polymer photocatalysts.


Assuntos
Poluentes Ambientais/química , Perileno/análogos & derivados , Perileno/química , Resinas Sintéticas/química , Catálise , Cromo/química , Corantes/química , Violeta Genciana/química , Luz , Oxirredução , Processos Fotoquímicos , Rodaminas/química , Propriedades de Superfície
11.
AAPS PharmSciTech ; 20(6): 245, 2019 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-31286294

RESUMO

Highly water-soluble prodrug micelle (50-fold compared with free MTX) of methotrexate-polyethyleneglycol-rhodamine (MTX-PEG-rhodamine) and MTX-mPEG was synthesized by the esterification reaction. The stability of the prodrug micelles was evaluated in phosphate buffer saline (PBS) with 10% fetal bovine serum (FBS). The tumor volume of the saline, MTX, and MTX-PEG-rhodamine groups was increased 3.7-fold, 2.8-fold, and 1.8-fold, respectively, compared with the initial tumor volume. TUNEL and drug distribution results further confirmed that the micelle of MTX-PEG-rhodamine possessed fewer side effects on the normal tissue compared with MTX. The prodrug micelle showed four advantages: retention of the drug activity site, higher water solubility of methotrexate (MTX), ease of preparation and application, and preferential accumulation in tumor tissues. These advantages of MTX-mPEG make it a promising drug delivery system (DDS) for clinical use.


Assuntos
Antimetabólitos Antineoplásicos/farmacologia , Metotrexato/farmacologia , Micelas , Polietilenoglicóis/química , Pró-Fármacos/farmacologia , Rodaminas/química , Água/química , Animais , Antimetabólitos Antineoplásicos/química , Sistemas de Liberação de Medicamentos , Feminino , Metotrexato/química , Camundongos , Camundongos Nus , Neoplasias/tratamento farmacológico , Pró-Fármacos/química , Solubilidade , Ensaios Antitumorais Modelo de Xenoenxerto
12.
J Nanobiotechnology ; 17(1): 81, 2019 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-31286976

RESUMO

BACKGROUND: Magnetic nanoparticles (MNPs) are characterized by unique physicochemical and biological properties that allow their employment as highly biocompatible drug carriers. Gelsolin (GSN) is a multifunctional actin-binding protein involved in cytoskeleton remodeling and free circulating actin sequestering. It was reported that a gelsolin derived phosphoinositide binding domain GSN 160-169, (PBP10 peptide) coupled with rhodamine B, exerts strong bactericidal activity. RESULTS: In this study, we synthesized a new antibacterial and antifungal nanosystem composed of MNPs and a PBP10 peptide attached to the surface. The physicochemical properties of these nanosystems were analyzed by spectroscopy, calorimetry, electron microscopy, and X-ray studies. Using luminescence based techniques and a standard killing assay against representative strains of Gram-positive (Staphylococcus aureus MRSA Xen 30) and Gram-negative (Pseudomonas aeruginosa Xen 5) bacteria and against fungal cells (Candida spp.) we demonstrated that magnetic nanoparticles significantly enhance the effect of PBP10 peptides through a membrane-based mode of action, involving attachment and interaction with cell wall components, disruption of microbial membrane and increased uptake of peptide. Our results also indicate that treatment of both planktonic and biofilm forms of pathogens by PBP10-based nanosystems is more effective than therapy with either of these agents alone. CONCLUSIONS: The results show that magnetic nanoparticles enhance the antimicrobial activity of the phosphoinositide-binding domain of gelsolin, modulate its mode of action and strengthen the idea of its employment for developing the new treatment methods of infections.


Assuntos
Antibacterianos/química , Antifúngicos/química , Gelsolina/química , Nanopartículas de Magnetita/química , Fragmentos de Peptídeos/química , Biofilmes , Candida/efeitos dos fármacos , Membrana Celular/metabolismo , Ouro/química , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Nanoconchas/química , Plâncton , Pseudomonas aeruginosa/efeitos dos fármacos , Rodaminas/química
14.
Opt Express ; 27(11): 15996-16011, 2019 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-31163787

RESUMO

In this paper, the dynamics of the spontaneous emission rate of Rhodamine 6G dye molecules, coupled into disorder-induced optical cavities in a scattering medium, is investigated by a time-resolved spectroscopic technique. The system is a wedge-type wave-guiding system formed by a polymer with randomly positioned air inclusions. The scattering of light in the medium induces transverse Anderson localization, which gives rise to quasi-optical modes or Anderson-localized cavities. The presence of these modes strongly enhances the decay emission of the emitters. The waveguide is fabricated by a conventional fiber drawing technique inside a fused silica micro-rod. Localized optical modes are observed to appear in the form of sharp spectral resonance peaks at various frequencies throughout the photoluminescence spectrum of the dye molecules. The spontaneous emission rate of the molecules on resonance with the localized modes is measured to enhance by a factor of up to 6.8, which elucidates that the transverse Anderson localization enables an efficient way to alter the spontaneous emission rate of quantum emitters in an optically asymmetric simple wedge-type photonic waveguide, offering a moderate alternative to highly engineered sophisticated light-wave devices.


Assuntos
Corantes Fluorescentes/química , Aumento da Imagem/métodos , Rodaminas/química , Espalhamento de Radiação , Ressonância de Plasmônio de Superfície/instrumentação
15.
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
16.
Int J Mol Sci ; 20(11)2019 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-31163601

RESUMO

The illegal adulteration of sildenafil in herbal food supplements and alcoholic drinks immensely threatens human health due to its harmful side-effects. Therefore, it is important to accurately detect and identify the presence of sildenafil in alcoholic drinks. In this study, Opto Trace Raman 202 (OTR 202) was used as surface enhanced Raman spectroscopy (SERS) active colloids to detect sildenafil. The results demonstrated that the Raman enhancement factor (EF) of OTR 202 colloids reached 1.84 × 107 and the limits of detection (LODs) of sildenafil in health wine and liquor were found to be as low as 0.1 mg/L. Moreover, the SERS peaks of 645, 814, 1235, 1401, 1530 and 1584 cm-1 could be qualitatively determined as sildenafil characteristic peaks and the relationship between Raman peak intensity and sildenafil concentration in health wine and liquor were different. There was a good linear correlation between Raman peak intensity, and sildenafil concentration in health wine ranged 0.1-1 mg/L (0.9687< R2 < 0.9891) and 1-10 mg/L (0.9701 < R2 < 0.9840), and in liquor ranged 0.1-1 mg/L (0.9662 < R2 < 0.9944) and 1-20 mg/L (0.9625 < R2 < 0.9922). The relative standard deviations (RSD) were less than 5.90% (sildenafil in health wine) and 9.16% (sildenafil in liquor). The recovery ranged 88.92-104.42% (sildenafil in health wine) and 90.09-104.55% (sildenafil in liquor). In general, the sildenafil in health wine and liquor could be rapidly and quantitatively determined using SERS technique, which offered a simple and accurate alternative for the determination of sildenafil in alcoholic drinks.


Assuntos
Bebidas Alcoólicas/análise , Citrato de Sildenafila/análise , Análise Espectral Raman , Vinho/análise , Limite de Detecção , Modelos Moleculares , Conformação Molecular , Nanopartículas/química , Reprodutibilidade dos Testes , Rodaminas/química , Citrato de Sildenafila/química , Análise Espectral Raman/métodos
17.
Analyst ; 144(14): 4362-4370, 2019 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-31197297

RESUMO

Optical spectroscopic imaging of biological systems has important applications in medical diagnosis, biochemistry, and image-guided surgery. Vibrational spectroscopy, such as Raman scattering, provides high chemical selectivity but is limited by weak signals and a large fluorescence background. Fluorescence imaging is often used by introducing specific dyes in biological systems to label different system parts and to increase the image contrast. However, the extrinsic fluorescence of the staining molecules often masks the intrinsic vibrational signals of biomolecules, which could also be simultaneously detected using the same excitation laser source. Therefore, fluorescence staining is often accompanied by the loss of other important complimentary information. For example, the high laser power often used for the rapid, high-quality imaging could lead to photo-induced suppression or bleaching of the fluorescence and Raman signals resulting in sample photodamage. Therefore, simultaneous imaging and photodamage analysis need to be performed in a controlled bioimaging experiment. Here we perform simultaneous spectroscopic bioimaging and photostability analysis of rhodamine 6G (R6G) stained red blood cells (RBCs) using both fluorescence and resonance Raman imaging in a single 532 nm laser excitation experiment. We develop a corresponding data processing algorithm which allows separation of the two spectroscopic signals. We control the relative intensity of the R6G and RBC signals by varying the excitation laser power and simultaneously monitor the photostability of RBCs. We observe no significant photodamage of RBCs through the absence of changes in the relative Raman peak intensities. Conversely, the R6G molecules show bleaching with the suppression of both the fluorescence and resonance Raman signals. Our approach may be generalized to other types of stained cells with the appropriate selection of fluorescent dyes and excitation sources.


Assuntos
Eritrócitos/citologia , Corantes Fluorescentes/química , Rodaminas/química , Animais , Bovinos , Luz , Rodaminas/efeitos da radiação , Espectrometria de Fluorescência , Análise Espectral Raman
18.
Analyst ; 144(14): 4258-4265, 2019 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-31215916

RESUMO

Biothiols such as cysteine (Cys), homocysteine (Hcy), glutathione (GSH) and hydrogen sulfide (H2S) are widely found in mammalian cells. They are closely related to the production and metabolic pathways and play very important roles in physiological and pathological activities. Therefore, the quantitative detection of these biothiols is of great significance. Although many fluorescent probes have been successfully used to track biothiols in biological samples, the fluorescence method for simultaneously detecting these biothiols using separated fluorescence emission channels under single wavelength excitation is still immature. In this work, we prepared the conjugate of seminaphthorhodafluor (SNARF) dye and 7-nitro-1,2,3-benzoxadiazole (NBD) using as a simple long-wavelength fluorescent probe SNARF-NBD for specific detection of biothiols. Cys/Hcy and GSH/H2S were identified by two separated fluorescence emission channels under single wavelength excitation, which showed good selectivity and sensitivity. In addition, SNARF-NBD has low cytotoxicity and shows good imaging ability in living cells and zebrafish.


Assuntos
Cisteína/análise , Corantes Fluorescentes/química , Glutationa/análise , Homocisteína/análise , Sulfeto de Hidrogênio/análise , Animais , Corantes Fluorescentes/toxicidade , Camundongos , Imagem Óptica/métodos , Oxidiazóis/química , Oxidiazóis/toxicidade , Células RAW 264.7 , Rodaminas/química , Rodaminas/toxicidade , Espectrometria de Fluorescência/métodos , Peixe-Zebra
19.
Anal Bioanal Chem ; 411(23): 5985-5992, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31236651

RESUMO

In this study, a novel near-infrared fluorescent off-on probe for H2S based on seminaphthorhodafluor fluorophore is designed and constructed, which could be used in detection with 121-fold (23-fold) fluorescent (absorbance) enhancement at 630 nm (572 nm), fast responsiveness (completed within 5 min), high sensitivity, and lower cellular autofluorescence interference. Based on these excellent optical properties, the probe was employed to monitor H2S in red wine samples with satisfactory results. Moreover, the probe was successfully applied for monitoring and imaging H2S quantitatively in Hela cells and live athymic nude mice, indicating its potential application in biological science.


Assuntos
Benzopiranos/química , Corantes Fluorescentes/química , Sulfeto de Hidrogênio/análise , Naftóis/química , Imagem Óptica/métodos , Rodaminas/química , Animais , Células HeLa , Humanos , Raios Infravermelhos , Camundongos Nus , Microscopia de Fluorescência/métodos
20.
Anal Bioanal Chem ; 411(21): 5563-5576, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31209547

RESUMO

The Surface-enhanced Raman spectroscopy (SERS) method based on gold nanoparticles as SERS substrate was investigated for the label-free detection and quantification of probiotic bacteria that are widely used in various pharmaceutical formulations. Indeed, the development of a simple and fast SERS method dedicated to the quantification of bacteria should be very useful for the characterization of such formulations in a more convenient way than the usually performed tedious and time-consuming conventional counting method. For this purpose, uncoated near-spherical gold nanoparticles were developed at room temperature by acidic treatment of star-like gold nanoparticle precursors. In this study, we first investigated the influence of acidic treatment conditions on both the nanoparticle physicochemical properties and SERS efficiency using Rhodamine 6G (R6G) as "model" analyte. Results highlighted that an effective R6G Raman signal enhancement was obtained by promoting chemical effect through R6G-anion interactions and by obtaining a suitable aggregation state of the nanoparticles. Depending on the nanoparticle synthesis conditions, R6G SERS signals were up to 102-103-fold greater than those obtained with star-like gold nanoparticles. The synthesized spherical gold nanoparticles were then successfully applied for the detection and quantification of Lactobacillus rhamnosus GG (LGG). In that case, the signal enhancement was especially due to the combination of anion-induced chemical enhancement and nanoparticle aggregation on LGG cell wall consecutive to non-specific interactions. Both the simplicity and speed of the procedure, achieved under 30 min, including nanoparticle synthesis, sample preparation, and acquisition of SERS spectra, appeared as very relevant for the characterization of pharmaceutical formulations incorporating probiotics. Graphical abstract.


Assuntos
Ouro/química , Lactobacillus rhamnosus/isolamento & purificação , Nanopartículas Metálicas/química , Análise Espectral Raman/métodos , Probióticos , Rodaminas/química , Espectrofotometria Ultravioleta
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