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1.
J Sep Sci ; 46(13): e2200836, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37052362

RESUMEN

Metal-organic framework materials are a class of novel crystalline porous materials with regular pore structures formed by covalent bonding between metal centers and organic functional groups. Metal-organic framework materials have attracted great interest in analytical chemistry due to their unique properties such as good stability and permanent porosity. In this work, D-histidine was used to carry out chiral modification of zeolitic imidazolate framework-90 under mild conditions, and the D-histidine modified zeolitic imidazolate framework-90 coated capillary column was prepared. This chiral capillary column was used to separate epinephrine, norepinephrine, terbutaline, and tryptophan enantiomers. Under optimum conditions, baseline separations were achieved. The intra-day, inter-day, and inter-column relative standard deviations (n = 3) of the four pairs of enantiomeric migration times were 0.15%-0.56%, 0.74%-2.40%, and 1.93%-3.18%, respectively. Moreover, the D-histidine modified zeolitic imidazolate framework-90 coated capillary could be reused for at least 150 runs without significant changes in the separation efficiency and migration time.

2.
Inorg Chem ; 61(45): 18162-18169, 2022 Nov 14.
Artículo en Inglés | MEDLINE | ID: mdl-36318752

RESUMEN

A series of lanthanide-containing water-resistant nitrates, namely RE(OH)2NO3 (RE = Tb(1), Dy(2), Ho(3), and Er(4)), was obtained through the hydrothermal process. As possible nonlinear optical materials, they feature a layered isomorph composed of an [REO3(OH)6] polyhedron and an [NO3] triangle, and the synergistic arrangement of the [REO3(OH)6] and [NO3] groups in their structures leads to their obvious second-order nonlinear optical effect. Nevertheless, the unique optical absorption caused by the electronic transitions on 4f-4f orbitals of lanthanides results in their second harmonic generation responses of different strengths, with 1 exhibiting 5.07 times that of KDP, but 2-4 showing less than half of KDP. In addition, 1 possesses an outstanding water-resistant capacity and a transparent cut-off edge around 300 nm, foreshadowing its potential value as a nonlinear optical crystal. Moreover, 1 is found to emit characteristic green fluorescence due to the typical 5D4 → 7F5 transitions of the excited Tb3+ ions.

3.
Anal Bioanal Chem ; 414(23): 6989-7000, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35982252

RESUMEN

Uracil DNA glycosylase (UDG) and human alkyladenine DNA glycosylase (hAAG) are the important DNA glycosylases for initiating the repair of DNA damage, and the aberrant expression of DNA glycosylases is closely associated with various diseases, such as Parkinson's disease, several cancers, and human immunodeficiency. The simultaneous detection of UDG and hAAG is helpful for the study of early clinical diagnosis. However, the reported methods for multiple DNA glycosylase assay suffer from the application of an expensive single-molecule instrument, labor-tedious magnetic separation, and complicated design. Herein, we develop a simple fluorescence method with only three necessary DNA strands for the selective and sensitive detection of multiple DNA glycosylase activity based on the generation of 3'-OH terminal-triggered encoding of multicolor fluorescence. The method can achieve the detection limits of 5.5 × 10-5 U/mL for UDG and 3.3 × 10-3 U/mL for hAAG, which are lower than those of the reported fluorescence methods. Moreover, it can be further used to detect multiple DNA glycosylases in the human cervical carcinoma cell line (HeLa cells), normal human renal epithelial cells (293 T cells), and biological fluid and measure the enzyme kinetic parameters of UDG and hAAG.


Asunto(s)
ADN , Uracil-ADN Glicosidasa , Fluorescencia , Células HeLa , Humanos
4.
Macromol Rapid Commun ; 43(22): e2100810, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-35080281

RESUMEN

Molecular structural modifications are utilized to improve the short-circuit current (JSC ) of high-voltage organic photovoltaics (OPVs). Herein, the classic non-fullerene acceptor (NFA), BTA3, is chosen as a benchmark, with BTA3b containing the linear alkyl chains on the middle core and JC14 fusing thiophene on the benzotriazole (BTA) unit as a contrast. The photovoltaic devices based on J52-F: BTA3b and J52-F: JC14 achieve wider external quantum efficiency responses with band edges of 730 and 800 nm, respectively than that of the device based on J52-F: BTA3 (715 nm). The corresponding  JSC increases to 14.08 and 15.78 mA cm-2 , respectively, compared to BTA3 (11.56 mA cm-2 ). The smaller Urbach energy and higher electroluminescence efficiency guarantee J52-F: JC14 a decreased energy loss (0.528 eV) and a high open-circuit voltage (VOC ) of 1.07 V. Finally, J52-F: JC14 combination achieves an increased power conversion efficiency (PCE) of 10.33% than that of J52-F: BTA3b (PCE = 9.81%) and J52-F: BTA3 (PCE = 9.04%). Overall, the research results indicate that subtle structure modification of NFAs, especially introducing fused rings, is a simple and effective strategy to extend the photoelectric response, boosting the  JSC and ensuring a high VOC beyond 1.0 V.

5.
Anal Chem ; 93(12): 5185-5193, 2021 03 30.
Artículo en Inglés | MEDLINE | ID: mdl-33729748

RESUMEN

In order to understand related pathogenesis of some diseases and design new intracellular drug delivery systems, investigation of pH change in living cells in real time is important. In this paper, a new style of fluorescent silicon nanoparticles (SiNPs) as a pH-sensitive probe and for the visualization of the pH changes in cells was designed and prepared using 4-aminophenol as a reducing agent and N-aminoethyl-γ-aminopropyltrimethyl as a silicon source by a one-pot hydrothermal method. It was particularly noteworthy that the fluorescence intensity emitted from the SiNPs positively correlated with the pH value of solutions, making the SiNPs a viable probe used for sensitive sensing of pH. At the same time, a response of the probe to the pH was found in 5.0-10.0, and the SiNPs have an excellent biocompatibility (e.g., ∼74% of cell viability was remained after treatment for 24 h at 500 µg/mL of the SiNPs). The proposed method that could display the change in pH of live cells provided an effective means for visually diagnosing diseases related to intracellular pH.


Asunto(s)
Nanopartículas , Silicio , Supervivencia Celular , Fluorescencia , Concentración de Iones de Hidrógeno , Dióxido de Silicio
6.
Mikrochim Acta ; 187(4): 233, 2020 03 16.
Artículo en Inglés | MEDLINE | ID: mdl-32180017

RESUMEN

Two-dimensional (2D) COFs have been successfully applied for various applications, such as capillary electrochromatography (CEC). Compared with 2D COFs, three-dimensional (3D) COFs have higher surface area and lower density, which should have superior potential as the separation medium in CEC. However, the 3D COFs on the inner wall of capillary is hard to fabricate in situ. Up to date, the application of 3D COFs in open-tubular capillary electrochromatography (OT-CEC) is still considered a challenge. For the first time the COF-300-coated capillary was prepared by in situ growth (COF-300 was made from terephthalaldehyde and tetra-(4-anilyl)-methane) on OT-CEC. Benzene, methylbenzene, styrene, ethylbenzene, naphthalene, 1-methylnaphthalene, and propylbenzene were used to evaluate the performance of the COF-300-coated capillary by OT-CEC. For three consecutive runs, the intraday relative standard deviations (RSDs) of migration time and peak areas were 0.1-0.4% and 2.5-8.3%, respectively. The interday RSDs of migration time and peak areas were 0.2-0.5% and 1.0-10.8%, respectively. Five groups of aromatic co mpounds were used to further study the separation mechanism, which indicated that hydrophobic interaction and size selection interaction are the main factors. It should be noted that the COF-300-coated capillary can be used for more than 140 runs with no observable changes of the separation efficiency. Graphical abstract The 3D COF-300-coated capillary was prepared by in situ growth for OT-CEC. Six groups of aromatic compounds were separated by 3D COF-300-coated capillary. Size selection and hydrophobic interaction affect the migration time of analytes.


Asunto(s)
Aldehídos/química , Hidrocarburos Aromáticos/aislamiento & purificación , Metano/química , Electrocromatografía Capilar , Hidrocarburos Aromáticos/química , Metano/análogos & derivados
7.
Anal Chem ; 91(24): 15477-15483, 2019 12 17.
Artículo en Inglés | MEDLINE | ID: mdl-31756070

RESUMEN

Hypochlorite (ClO-) and ascorbic acid (AA) are reported to have a high correlation with oxidative stress and related diseases, so it is necessary and critical to develop sensitive and fast response sensors to investigate the dynamical variation of these redox substances, especially those sensors which can detect ClO- and AA in real time in two manners. However, it is still an unmet challenge for now. Herein, novel carbon dots (RD-CDs) which can respond to ClO- and AA rapidly, reversibly, and dynamically by fluorescence and colorimetry were synthesized. In the fluorescence manner, the constructed nanosensor possessed high selectivity toward ClO- in the range of 0.1-100 µM with a detection limit of 83 nM, and can be selectively recovered by AA. It endows this sensor with good capacity as a fluorescent probe for dynamic detection of ClO- and AA in living cells, which can be monitored by a fluorescence microscope. In the colorimetric manner, ClO- and AA can be detected by UV-vis in the range of 5-200 µM and 1-30 µM, respectively. The concentrations of ClO- and AA in humor can be measured by RD-CDs in both fluorescence and colorimetric mode. The results above-mentioned demonstrate its great potential in biosensing.


Asunto(s)
Carbono/química , Colorimetría/métodos , Ácido Hipocloroso/química , Espectrometría de Fluorescencia/métodos , Animales , Ácido Ascórbico , Bovinos , Colorantes Fluorescentes , Células HeLa , Humanos , Límite de Detección , Ratones , Puntos Cuánticos , Células RAW 264.7 , Ratas
8.
Hepatology ; 67(5): 1943-1955, 2018 05.
Artículo en Inglés | MEDLINE | ID: mdl-29220536

RESUMEN

The scavenger receptor CD36 recognizes a diverse set of ligands and has been implicated in a wide variety of normal and pathological processes, including lipid metabolism, angiogenesis, atherosclerosis, and phagocytosis. In particular, recent findings have demonstrated its crucial functions in sterile inflammation and tumor metastasis. However, the role of CD36 in immune-mediated hepatitis remains unclear. Concanavalin A (ConA)-induced liver injury is a well-established experimental T cell-mediated hepatitis. To understand the role of CD36 in hepatitis, we tested the susceptibility of CD36-deficient (CD36-/- ) mice to this model, evaluated by a liver enzyme test, terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay, histological analysis, mononuclear cell (MNC) infiltration, and hepatic proinflammatory factor production. CD36-/- mice were less sensitive to ConA-induced hepatitis and had a significantly lower number of liver MNCs (LMNCs), including CD4+ cells, CD8+ T cells, natural killer cells, natural killer T cells, infiltrating macrophages, and neutrophils, as well as reduced expression of inflammatory mediators (tumor necrosis factor α, CXC chemokine ligand (CXCL) 10, interleukin (IL)-1α, monocyte chemotactic protein 1, and IL-6) compared with controls. Notably, we used bone marrow chimeric mice to demonstrate that CD36 expression on nonhematopoietic cells was required to drive ConA-induced liver injury. Furthermore, our data show that the CD36 receptor was essential for CXCL10-induced hepatocyte apoptosis and activation of IκB kinase, Akt, and Jun N-terminal kinase. Moreover, treatment of wild-type mice with genistein, a tyrosine kinase inhibitor that blocks CD36-Lyn signaling, attenuated ConA-induced liver injury and reduced the number of MNCs. CONCLUSIONS: Our findings suggest that CD36 plays an important proinflammatory role in ConA-induced liver injury by promoting hepatic inflammation and mediating the proapoptotic effect of chemokine CXCL10, and therefore, may be a potential therapeutic target for immune-mediated hepatitis. (Hepatology 2018;67:1943-1955).


Asunto(s)
Trastornos de las Plaquetas Sanguíneas/patología , Antígenos CD36/metabolismo , Enfermedad Hepática Inducida por Sustancias y Drogas/metabolismo , Quimiocina CXCL10/metabolismo , Enfermedades Genéticas Congénitas/patología , Hepatitis/metabolismo , Animales , Apoptosis/efectos de los fármacos , Trastornos de las Plaquetas Sanguíneas/inmunología , Enfermedad Hepática Inducida por Sustancias y Drogas/patología , Concanavalina A/farmacología , Citocinas/metabolismo , Modelos Animales de Enfermedad , Citometría de Flujo , Enfermedades Genéticas Congénitas/inmunología , Genisteína/farmacología , Hepatitis/inmunología , Hepatitis/patología , Hepatocitos/metabolismo , Hígado/patología , Ratones , Ratones Endogámicos C57BL , Transducción de Señal
9.
Langmuir ; 35(14): 4806-4812, 2019 04 09.
Artículo en Inglés | MEDLINE | ID: mdl-30865827

RESUMEN

The continuous development of semiconductor quantum dots (QDs) in biochemical research has attracted special attention, and surface functionalizing becomes more important to optimize their performance. Ligand exchange reactions are commonly used to modify the surface of QDs for their biomedical applications. However, the kinetics of ligand exchange for semiconductor QDs remain fully unexplored. Here, we describe a simple and rapid method to characterize the ligand exchange reactions on CdSe/ZnS QDs by capillary electrophoresis (CE). The results of ultraviolet-visible absorption spectra, fluorescence spectra, and Fourier transform infrared spectroscopy indicated the successful implementation of the ligand exchange process. The dynamics of ligand exchange of OA-coated CdSe/ZnS QDs with 4-mercaptobenzoic acid was monitored by CE, and the observed ligand exchange trends were fitted with logistic functions. When the ligand exchange reactions reached equilibrium, the ligand density of QDs can be quantified by CE. It is anticipated that CE will be a new powerful technique for quantitative analysis of the ligand exchange reactions on the surface of QDs.

10.
Analyst ; 144(9): 3064-3071, 2019 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-30916676

RESUMEN

DNA glycosylase (DG) plays a significant role in repairing DNA lesions, and the dysregulation of DG activity is associated with a variety of human pathologies. Thus, the detection of DG activity is essential for biomedical research and clinical diagnosis. Herein, we develop a facile fluorometric method based on the base excision repair (BER) mediated cascading triple-signal amplification for the sensitive detection of DG. The presence of human alkyladenine DNA glycosylase (hAAG) can initiate the cleavage of the substrate at the mismatched deoxyinosine site by endonuclease IV (Endo IV), resulting in the breaking of the DNA substrate. The cleaved DNA substrate functions as both a primer and a template to initiate strand displacement amplification (SDA) to release primers. The released primers can further bind to a circular template to induce an exponential primer generation rolling circle amplification (PG-RCA) reaction, producing a large number of primers. The primers that resulted from the SDA and PG-RCA reaction can induce the subsequent recycling cleavage of signal probes, leading to the generation of a fluorescence signal. Taking advantage of the high amplification efficiency of triple-signal amplification and the low background signal resulting from single uracil repair-mediated inhibition of nonspecific amplification, this method exhibits a low detection limit of 0.026 U mL-1 and a large dynamic range of 4 orders of magnitude for hAAG. Moreover, this method has distinct advantages of simplicity and low cost, and it can further quantify the hAAG activity from HeLa cell extracts, holding great potential in clinical diagnosis and biomedical research.


Asunto(s)
ADN Glicosilasas/sangre , Reparación del ADN , ADN/química , Pruebas de Enzimas/métodos , Fluorometría/métodos , Secuencia de Bases , ADN Polimerasa Dirigida por ADN/química , Desoxirribonucleasa IV (Fago T4-Inducido)/química , Fluorescencia , Colorantes Fluorescentes/química , Geobacillus stearothermophilus/enzimología , Células HeLa , Humanos , Límite de Detección , Técnicas de Amplificación de Ácido Nucleico/métodos , Uracil-ADN Glicosidasa/química
11.
Mikrochim Acta ; 186(3): 163, 2019 02 06.
Artículo en Inglés | MEDLINE | ID: mdl-30725229

RESUMEN

The authors describe a one-step method for the preparation of yellow fluorescent carbon dots (CDs) starting from 4-aminoacetanilide hydrochloride and 4-acetamidobenzaldehyde. The CDs have excitation/emission peaks at 470/550 nm, good water solubility, salt-tolerance and photostability. Their fluorescence is quenched by hexavalent chromium [Cr(VI)] via static quenching. Fluorescence intensity drops linearly in the 1 to 400 µM Cr(VI) concentration range, and the limit of detection is 0.13 µM. This method is selective for Cr(VI) over potential metal ion interferences and was successfully applied to the detection of Cr(VI) in spiked water and biological tissue samples. Recoveries from spiked samples ranged from 97.7% to 103.8%. Graphical abstract Schematic presentation of (a) the preparation of the CD fluorescent probe and (b), the principle of Cr(VI) determination.

12.
Mikrochim Acta ; 186(2): 58, 2019 01 07.
Artículo en Inglés | MEDLINE | ID: mdl-30617543

RESUMEN

The authors describe a fluorometric strategy for the determination of dopamine (DA). It is based on the use of aptamer-functionalized MoS2 quantum dots (QDs) and MoS2 nanosheets (NSs). The QDs and NSs were extensively characterized with regard to their physical and chemical properties using methods such as TEM, XRD, FT-IR, EDX and molecular spectroscopies. The aptamer against dopamine was labeled with QDs acting as the energy donor in an energy transfer system, while the NSs serve as the energy acceptor. Under the optimal conditions, the fluorescence (FL) intensity (best measured at excitation/emission peaks of 315/412 nm) increases with increasing DA concentration in the range from 0.1 nM to 1000 nM, with a lower detection limit of 45 pM. The method was successfully applied to the determination of DA in complex matrices. In our perception, the method has a wide scope in that it may be extended to other biomolecules for which respective aptamer are available. The QDs show excellent optical properties, good stability, low cytotoxicity, and may also be applied to fluorometric imaging of live cells. Graphical abstract A "turn-on" fluorometric aptasensor for the determination of dopamine (DA) was established based on aptamer-functionalized molybdenum disulfide quantum dots (MoS2 QDs) and MoS2 nanosheets. This assay exhibits high selectivity and sensitivity with a detection limit as low as 45 pM.


Asunto(s)
Aptámeros de Nucleótidos/química , ADN/química , Disulfuros/química , Dopamina/análisis , Transferencia Resonante de Energía de Fluorescencia/métodos , Molibdeno/química , Puntos Cuánticos/química , Secuencia de Bases , Técnicas Biosensibles/métodos , Disulfuros/toxicidad , Células HeLa , Humanos , Límite de Detección , Molibdeno/toxicidad , Puntos Cuánticos/toxicidad
14.
Analyst ; 143(19): 4585-4591, 2018 Sep 24.
Artículo en Inglés | MEDLINE | ID: mdl-30156585

RESUMEN

ß-Secretase (BACE1) is an important drug target in the treatment of Alzheimer's disease (AD). Therefore, sensitive detection of BACE1 is essential for AD treatment and drug discovery. In this work, a facile and sensitive fluorescence biosensing platform was developed for BACE1 detection. This sensing platform was constituted based on the interaction between a WS2 nanosheet and a peptide sequence. In the absence of BACE1, a FAM-labeled peptide substrate could be adsorbed on the surface of the WS2 nanosheet, thereby quenching its fluorescence. However, in the presence of BACE1, the hydrolysis of the peptide substrate by BACE1 triggers could occur with the subsequent release of short FAM-linked peptide fragments which could not be adsorbed on the surface of the WS2 nanosheet. This resulted in weak fluorescence quenching, thus restoring the fluorescence signal. By measuring the change in the fluorescence of the FAM-labeled peptide substrate, the fluorescence sensing platform based on the WS2 nanosheet could monitor BACE1. The proposed WS2 nanosheet-based platform exhibited excellent specificity and high sensitivity with a detection limit of 66 pM for BACE1. Importantly, we also demonstrated that this platform was suitable for the screening of BACE1 inhibitors. The proposed sensing platform not only provides a novel strategy for the BACE1 assay but also offers a potential tool for screening drugs.


Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/análisis , Ácido Aspártico Endopeptidasas/análisis , Técnicas Biosensibles , Nanoestructuras , Péptidos/química , Enfermedad de Alzheimer , Animales , Límite de Detección , Ratas , Espectrometría de Fluorescencia
15.
J Immunol ; 196(11): 4477-86, 2016 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-27183592

RESUMEN

Ab maturation as well as memory B and plasma cell differentiation occur primarily in the germinal centers (GCs). Systemic lupus erythematosus (SLE) may develop as a result of enhanced GC activity. Previous studies have shown that the dysregulated STAT3 pathway is linked to lupus pathogenesis. However, the exact role of STAT3 in regulating SLE disease progression has not been fully understood. In this study, we demonstrated that STAT3 signaling in B cells is essential for GC formation and maintenance as well as Ab response. Increased cell apoptosis and downregulated Bcl-xL and Mcl-1 antiapoptotic gene expression were found in STAT3-deficient GC B cells. The follicular helper T cell response positively correlated with GC B cells and was significantly decreased in immunized B cell STAT3-deficient mice. STAT3 deficiency also led to the defect of plasma cell differentiation. Furthermore, STAT3 deficiency in autoreactive B cells resulted in decreased autoantibody production. Results obtained from B cell STAT3-deficient B6.MRL/lpr mice suggest that STAT3 signaling significantly contributes to SLE pathogenesis by regulation of GC reactivity, autoantibody production, and kidney pathology. Our findings provide new insights into the role of STAT3 signaling in the maintenance of GC formation and GC B cell differentiation and identify STAT3 as a novel target for treatment of SLE.


Asunto(s)
Linfocitos B/inmunología , Linfocitos B/metabolismo , Centro Germinal/citología , Centro Germinal/inmunología , Lupus Eritematoso Sistémico/inmunología , Factor de Transcripción STAT3/metabolismo , Transducción de Señal , Animales , Modelos Animales de Enfermedad , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Factor de Transcripción STAT3/deficiencia
16.
Mikrochim Acta ; 185(11): 518, 2018 10 25.
Artículo en Inglés | MEDLINE | ID: mdl-30361830

RESUMEN

The authors describe a method for the preparation of orange-red emissive carbon dots (CDs) with excitation/emission peaks at 520/582 nm. The CDs were hydrothermally prepared by a one-pot strategy from trimesic acid and 4-aminoacetanilide. The fluorescence of the CDs is strongly quenched by hydrogen peroxide. The oxidation of glucose by glucose oxidase (GOx) produces H2O2 that quenches the fluorescence via static quenching. Based on this phenomenon, a fluorometric method was established for the determination of glucose. Under the optimum conditions, response is linear in the 0.5 to 100 µM glucose concentration range, with a 0.33 µM limit of detection. The method is selective for glucose over its analogues and was successfully applied to the determination of glucose in diluted human serum and in urine from diabetics and healthy individuals. Recoveries from spiked samples range from 98.7 to 102.5%. Graphical abstract (a) One-step synthetic strategy of the CDs; (b) Schematic illustration of the CDs for glucose detection.


Asunto(s)
Técnicas Biosensibles/métodos , Carbono/química , Fluorometría/métodos , Glucosa Oxidasa/metabolismo , Glucosa/análisis , Puntos Cuánticos/química , Glucemia/análisis , Técnicas de Química Sintética , Color , Humanos , Peróxido de Hidrógeno/química , Nanotecnología
17.
Anal Chem ; 89(5): 3001-3008, 2017 03 07.
Artículo en Inglés | MEDLINE | ID: mdl-28192949

RESUMEN

Because 2,4,6-trinitrophenol (TNP) and its analogues such as 2,4,6-trinitrotoluene (TNT) possess similar chemical structures and properties, the reliable and accurate detection of TNP from its analogues still remains a challenging task. In the present work, a selective and sensitive method based on the water-soluble silicon nanoparticles (SiNPs) for the determination of TNP was established. The SiNPs with good thermostability and excellent antiphotobleaching capability were prepared via a simple one-pot method. Compared with the synthesized time of other nanomaterials with respect to the detection of TNP, this method avoided a multistep and time-consuming synthesis procedure. Significantly, the fluorescence of the SiNPs could be remarkably quenched by TNP via an inner filter effect. A wide linear range was obtained from 0.02 to 120 µg/mL with a limit of detection of 6.7 ng/mL. The method displayed excellent selectivity toward TNP over other nitroaromatic explosives. The proposed fluorescent method was successfully applied to the analysis of TNP. Moreover, a straightforward and convenient fluorescent filter paper sensor was developed for the detection of TNP, providing a valuable platform for TNP sensing in public safety and security.

18.
Anal Chem ; 89(24): 13626-13633, 2017 12 19.
Artículo en Inglés | MEDLINE | ID: mdl-29144732

RESUMEN

Recently, the development of new fluorescent probes for the ratiometric detection of target objects inside living cells has received great attention. Normally, the preparation, modification as well as conjugation procedures of these probes are complicated. On this basis, great efforts have been paid to establish convenient method for the preparation of dual emissive nanosensor. In this work, a functional dual emissive carbon dots (dCDs) was prepared by a one-pot hydrothermal carbonization method. The dCDs exhibits two distinctive fluorescence emission peaks at 440 and 624 nm with the excitation at 380 nm. Different from the commonly reported dCDs, this probe exhibited an interesting wavelength dependent dual responsive functionality toward lysine (440 nm) and pH (624 nm), enabling the ratiometric detection of these two targets. The quantitative analysis displayed that a linear range of 0.5-260 µM with a detection limit of 94 nM toward lysine and the differentiation of pH variation from 1.5 to 5.0 could be readily realized in a ratiometric strategy, which was not reported before with other carbon dots (CDs) as the probe. Furthermore, because of the low cytotoxicity, good optical and colloidal stability, and excellent wavelength dependent sensitivity and selectivity toward lysine and pH, this probe was successfully applied to monitor the dynamic variation of lysine and pH in cellular systems, demonstrating the promising applicability for biosensing in the future.


Asunto(s)
Carbono/química , Lisina/análisis , Puntos Cuánticos/química , Fluorescencia , Células HeLa , Humanos , Concentración de Iones de Hidrógeno , Estructura Molecular , Imagen Óptica , Tamaño de la Partícula , Propiedades de Superficie
19.
Analyst ; 142(13): 2419-2425, 2017 Jul 07.
Artículo en Inglés | MEDLINE | ID: mdl-28561084

RESUMEN

Sensitive detection of a low abundant protein is essential for biomedical research and clinical diagnostics. Herein, we develop a label-free colorimetric biosensor for the sensitive detection of recombinant human vascular endothelial growth factor-165 (VEGF165). This biosensor consists of an aptamer-based hairpin probe, an assistant DNA-trigger duplex and a linear template. In the presence of VEGF165, the specific binding of VEGF165 with the aptamer-based hairpin probe results in the opening of a hairpin probe and the opened hairpin probe subsequently hybridizes with the single-stranded region of the assistant DNA-trigger duplex to initiate the strand displacement amplification (SDA) to yield abundant triggers. The released triggers can further function as the primers to anneal with the hairpin probe and lead to the opening of the hairpin structure, which subsequently hybridizes with the assistant DNA-trigger duplex to initiate the next round of SDA reaction and generates more triggers. Large amounts of triggers could be generated by the synergistic operation of dual SDA reaction, and the obtained triggers can initiate a new round of SDA reaction to yield numerous G-quadruplex DNAzymes, which subsequently catalyze the conversion of ABTS2- to ABTS˙- by H2O2 to yield a color change with the assistance of a cofactor hemin. In contrast, in the absence of target VEGF165, the hairpin probe, the assistant DNA-trigger duplex and the linear template can stably coexist in solution, and thus no color change is observed because no trigger can initiate SDA to generate the G-quadruplex DNAzyme. This biosensor has a low detection limit of 1.70 pM and a dynamic range over 3 orders of magnitude from 24.00 pM to 11.25 nM. Moreover, the biosensor shows excellent specificity toward the target VEGF165 and the entire reaction can be carried out in an isothermal manner without the involvement of a high precision thermal cycler, making the current assay extremely cost effective.


Asunto(s)
Técnicas Biosensibles , Colorimetría , Factor A de Crecimiento Endotelial Vascular/análisis , Aptámeros de Nucleótidos , ADN Catalítico , Humanos , Peróxido de Hidrógeno , Técnicas de Amplificación de Ácido Nucleico
20.
J Sep Sci ; 40(12): 2645-2653, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28471055

RESUMEN

Inspired by the chiral recognition ability of ß-cyclodextrin and the natural adhesive properties of polydopamine under alkaline conditions, in this study, a rapid and in situ modification strategy was developed to fabricate ß-cyclodextrin/polydopamine composite material coated-capillary columns for open tubular capillary electrochromatography. The results of scanning electron microscopy, FTIR spectroscopy, streaming potential, and electro-osmotic flow studies indicated that ß-cyclodextrin/polydopamine was successfully fixed on the inner wall of the capillary column. This coating can be achieved within 1 h affording a greatly reduced capillary preparation time. The performance of the ß-cyclodextrin/polydopamine-coated capillary was validated by the analysis of seven pairs of chiral analytes, namely epinephrine, norepinephrine, isoprenaline, terbutaline, verapamil, tryptophane, carvedilol. Good enantioseparation efficiencies were achieved for all. For three consecutive runs, the relative standard deviations for the migration times of the analytes for intraday, interday, and column-to-column repeatability were in the range of 0.41-1.74, 1.03-4.18, and 1.66-8.24%, respectively. Moreover, the separation efficiency of the ß-cyclodextrin/polydopamine-coated capillary column did not decrease obviously over 90 runs. The strategy should also be feasible to introduce and immobilize other chiral selectors on the inner walls surface of capillary columns.


Asunto(s)
Electrocromatografía Capilar , Indoles , Polímeros , beta-Ciclodextrinas , Carbazoles , Carvedilol , Epinefrina , Isoproterenol , Norepinefrina , Propanolaminas , Estereoisomerismo , Terbutalina , Triptófano , Verapamilo
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