Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 298
Filtrar
1.
Anal Chem ; 2019 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-31692335

RESUMO

Electrochemiluminescence immunoassays are usually carried out through "on-electrode" strategy i.e., sandwich-type immunoassay format, the sensitivity of which is restricted by two key bottlenecks: (1) the number of signal labels is limited, and (2) only a part of signal labels could participate in the electrode reaction. In this perspective article, we discuss the development of "in-electrode" Faraday cage-type concept based immunocomplex immobilization strategy. The biggest difference from the traditional sandwich-type one is that, the designed "in-electrode" Faraday cage-type immunoassay uses a conductive two-dimensional (2-D) nanomaterial simultaneously coated with signal labels and recognition component as the detection unit, which could directly overlap on the electrode surface. In such a case, electrons could flow freely from the electrode to the detection unit, the outer Helmholtz plane (OHP) of the electrode is extended, and thousands of signal labels coated on the 2-D nanomaterial are all electrochemically "effective". Thus then, bottlenecks above-mentioned obstructing the improvement of the sensitivity in sandwich-type immunoassay are eliminated, and resulting much higher sensitivity of Faraday cage-type immunoassay can be obtained. And, the applications of the proposed versatile "in-electrode" Faraday cage-type immunoassay have been explored in the detection of target polypeptide, protein, pathogen and microRNA, with the detection sensitivity improved tens to hundreds of times. Finally, outlook and challenges in the field are summaried. The rise of Faraday cage-type electrochemiluminescence immunoassay (FCT-ECLIA) based biosensing strategies opens new horizons for wide range of early clinical identification and diagnostic applications.

2.
Biosci Rep ; 2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31670380

RESUMO

Fasudil is a derivative of 5-isoquinoline sulfonamide, which is a Rho kinase inhibitor, a wide range of pharmacological effects. Fasudil has been shown to attenuate kidney injury caused by certain substances. In the present study, metabolomic analysis of mouse kidney tissues ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry was used to determine the metabolomic changes in cisplatin-induced kidney injury and the fasudil-induced attenuation of cisplatin-induced kidney injury. Metabolomic profiling of kidney tissues revealed significant differences in metabolites between the control group and the cisplatin group and between the cisplatin group and the fasudil-intervention group. With metabolomic approach, 68 endogenous differential metabolites were found, and multivariate statistical analysis, accurate molecular weights, isotope tracers, mass-spectrometry secondary-fragment information, and standard-reference comparisons were used to identify these substances. Based on these differential metabolites, a metabolic-pathway network was constructed and revealed that fasudil primarily attenuated cisplatin-induced renal injury by modulating lipid and amino-acid metabolism. These results further demonstrate that kidney injury can be induced by cisplatin and, moreover, suggest that fasudil can be used to reduce kidney injury at early stages in patients treated with cisplatin.

3.
J Cell Mol Med ; 2019 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-31680444

RESUMO

Long noncoding RNA (lncRNA) has been suggested to play an important role in a variety of diseases over the past decade. In a previous study, we identified a novel lncRNA, termed HOXA11-AS, which was significantly up-regulated in calcium oxalate (CaOx) nephrolithiasis. However, the biological function of HOXA11-AS in CaOx nephrolithiasis remains poorly defined. Here, we demonstrated that HOXA11-AS was significantly up-regulated in CaOx nephrolithiasis both in vivo and in vitro. Gain-/loss-of-function studies revealed that HOXA11-AS inhibited proliferation, promoted apoptosis and aggravated cellular damage in HK-2 cells exposed to calcium oxalate monohydrate (COM). Further investigations showed that HOXA11-AS regulated monocyte chemotactic protein 1 (MCP-1) expression in HK-2 cell model of CaOx nephrolithiasis. In addition, online bioinformatics analysis and dual-luciferase reporter assay results showed that miR-124-3p directly bound to HOXA11-AS and the 3'UTR of MCP-1. Furthermore, rescue experiment results revealed that HOXA11-AS functioned as a competing endogenous RNA to regulate MCP-1 expression through sponging miR-124-3p and that overexpression of miR-124-3p restored the inhibitory effect of proliferation, promotion effects of apoptosis and cell damage induced by HOXA11-AS overexpression. Taken together, HOXA11-AS mediated CaOx crystal-induced renal inflammation via the miR-124-3p/MCP-1 axis, and this outcome may provide a good potential therapeutic target for nephrolithiasis.

4.
Gynecol Obstet Invest ; : 1-19, 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31505492

RESUMO

OBJECT: The purpose of this review is to assess the diagnostic performance of different imaging techniques for the detection of para-aortic lymph node (PALN) metastasis from gynecological malignancies. METHODS: Six databases, from the earliest available date of indexing through July 22, 2018, were systematically searched. In addition, the reference lists of relevant articles were searched by hand. Study allocation, data extraction, and quality assessment were independently performed by 2 reviewers. The size effect, sensitivity (SEN), specificity (SPE), positive likelihood ratio, negative likelihood ratio, diagnostic OR, and 95% CIs were used in the meta-analysis. The area under the curve (AUC) and Q* were calculated to reflect the synthesized diagnostic accuracy. Statistical calculations of this meta-analysis were conducted using STATA version 14.0 software. RESULTS: Across 41 eligible studies (1,615 participants), pooled SEN, SPE, and AUC of magnetic resonance imaging (MRI), computed tomography (CT), positron emission tomography (PET), PET-CT, and lymphangiography analyses were 25%, 93%, 0.7675; 60%, 94%, 0.9050; 83%, 96%, 0.9422; 66%, 97%, 0.9501; 77%, 75%, 0.8332, respectively. Analysis of combined summary receiver operating characteristic curves indicated that PET and PET-CT were superior to other imaging modalities. CONCLUSION: The present meta-analysis demonstrated that PET and PET-CT should be the first choice for detecting PALN metastasis in gynecological malignancies. CT was also suitable for confirmation. MRI was not recommended. Further studies are needed for PALN assessment.

5.
Biosens Bioelectron ; 143: 111616, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31472412

RESUMO

MicroRNAs are widely used as tumor markers for cancer diagnosis and prognosis. Herein, a multiple signal amplification sandwich-type SERS biosensor for femtomolar detection of miRNA is reported. The signal unit consisted of giant Au vesicles, DNA sequences and deposited silver nanoparticles. The giant Au vesicles provided large-volume hot spots because of sharp tips and abundant hotspot gaps, thus enhancing the electromagnetic intensity for the SERS performance. Further silver stain would easily lead to second-stage amplification of Raman signal. In addition, more SERS signal molecules R6G adsorbed on the signal unit with the aid of HCR and the controlled nanogaps between adjacent AgNPs, brought about the third-stage amplification. The capture unit, prepared by immobilizing the capture probe (CP) on the Fe3O4@AuNPs, could easily capture target miRNA and greatly simplify the separation step to improve reproducibility. The higher concentration of target miRNA definitely formed more sandwich-type structures with combination of capture unit and signal unit, resulting in multiple amplification of SERS signals. The proposed multiple signal amplification sandwich-type SERS biosensor could detect miRNA-141 at the femtomolar level with a low detection limit of 0.03 fM. Meanwhile, it exhibited high selectivity and accuracy, even for practical analysis in human serum. Therefore, the designed multiple signal amplification sandwich-type SERS biosensor would be a very promising alternative tool for the detection of miRNA and analogs in the field of biomedical diagnosis.

6.
Fitoterapia ; 138: 104294, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31398449

RESUMO

Two new eremophilane-type sesquiterpenes, carperemophilanes A and B (1-2), three new maleimide-bearing compounds, carpesiumaleimides A-C (3-5), along with a known sesquiterpene, carabrol (6), were isolated from the ethanol extract of Carpesium abrotanoides L. Their structures were elucidated by analysis of their NMR and MS data as well as by comparison with the literature. The absolute configuration of carperemophilane A (1) was determined by single-crystal X-ray diffraction analysis. All isolated compounds (1-6) were evaluated in vitro for cytotoxicity against two human cancer cell lines MDA-MB-231 and HGC-27 using the MTT method. Compounds 1, 2 and 6 showed cytotoxic activities with IC50 values ranging from 7.45 to 37.35 µM.

7.
J Transl Med ; 17(1): 278, 2019 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-31438987

RESUMO

BACKGROUND: Calcium oxalate (CaOx), the major constituent of most kidney stones, induces inflammatory infiltration and injures renal tubular cells. However, the role of γδT cells in CaOx-mediated kidney injury remains unclear. Therefore, this study investigated the distribution of intrarenal γδT cells and T cell receptor δ (TCRδ) immune repertoires in response to interactions with CaOx crystals. METHODS: CaOx crystal mouse model was established by glyoxylate injection. Flow cytometer was used to analyze the expression of CD69 and IL-17 from intrarenal γδT cells. Furthermore, TCR immune repertoire sequencing (IR-Seq) was used to monitor the profile of the TCRδ immune repertoire. RESULTS: Our results indicated that CaOx crystals lead to obvious increases in the expression and activation of intrarenal γδT cells. In TCRδ immune repertoire, the majority of V/J gene and V-J/V-D-J combination segments, barring individual exceptions, were similar between kidneys with CaOx formation and control kidneys. Impressively, high complementarity determining region 3 (CDR3) diversity was observed in response to CaOx crystal formation along with distinct CDR3 distribution and abundance. CONCLUSION: Our work suggests the presence of aberrant γδT cell activation and reconstitution of the TCRδ immune repertoire in response to CaOx crystal deposition.

8.
Mikrochim Acta ; 186(8): 512, 2019 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-31280366

RESUMO

A method is described for combined magnetic solid phase microextraction and electrochemiluminescent (ECL) detection of the antibiotic tetracycline. A nanocomposite of type Fe3O4@SiO2@ZnO was used as the sorbent. Tetracycline has a strong affinity for Zn(II) ion and therefore is well extracted by this sorbent. The loaded sorbent can be magnetically removed. The extraction efficiency at a 1.0 µM tetracycline concentration is around 88%. Detection is based on the use of carbon nanodots that were prepared form urea and ethylenediaminetetraacetic acid as raw materials. The electrochemical probe Ru(bpy)32+ was added to generate double ECL when scanning the potential between -3.5 and + 2 V. The two ECL signals decreased with the increase of tetracycline concentration. Under optimized experimental conditions, the ratio of the two signals is linearly related to the logarithm of the tetracycline concentration in the range from 1.0 nM to 0.1 mM, with a 0.47 nM detection limit. The method was successfully applied to the determination of tetracycline in spiked milk. It exhibited good sensitivity, selectivity and accuracy due to ratiometric read-out and prior preconcentration of analyte. Graphical abstract Tetracycline (TC) has a strong affinity for Zn(II) ion and is well extracted by the Fe3O4@SiO2@ZnO nanocomposite. Ru(bpy)32+ can generate double electrochemiluminescence signals based on the use of carbon nanodots (C-dots) as coreactant. The two signals decrease with the increase of tetracycline concentration. [Ru(bpy)32+]* stands for excited state Ru(bpy)22+.

9.
J Med Internet Res ; 21(5): e13168, 2019 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-31344676

RESUMO

BACKGROUND: Renal anemia is one of the most important complications in patients on maintenance hemodialysis (MHD). Telehealth-based dialysis registration systems have the advantage of real-time monitoring and have gradually been applied to the management of chronic diseases. OBJECTIVE: The objective of our study was to evaluate the impact of a telehealth-based dialysis registration system on patients on MHD in terms of renal anemia control. METHODS: The Red China project aimed to develop a dialysis registration system based on the WeChat mobile platform. Demographic and baseline laboratory parameters such as age, gender, primary disease, dialysis age, and baseline creatinine levels were recorded using this system. In addition, the hemoglobin and hematocrit levels were recorded monthly. The platform then generated a hemoglobin and hematocrit statistics report for each hemodialysis center monthly, including the detection rate, target rate, and distribution of hemoglobin and released it to physicians via the WeChat mobile phone app. The physicians were then able to treat the individual's anemia appropriately by changing the doses of erythropoiesis-stimulating agents or iron use on the basis of this report. We analyzed the demographic and baseline laboratory parameters, detection rate, target rate, and average level and distribution of hemoglobin 28 months after the launch of the project. RESULTS: A total of 8392 patients on MHD from 28 hemodialysis centers in Shanghai were enrolled from June 2015 to October 2017. The detection rate of hemoglobin increased from 54.18% to 73.61% (P<.001), the target rate of hemoglobin increased from 47.55% to 56.07% (P<.001), and the mean level of hemoglobin increased from 10.83 (SD 1. 60) g/dL to 11.07 (SD 1.60) g/dL (P<.001). In addition, the proportion of patients with hemoglobin levels ≥11 g/dL but <13 g/dL increased from 40.40% to 47.48%. CONCLUSIONS: This telehealth-based dialysis registration system can provide timely reporting of the anemia status in patients on MHD, which may improve the awareness of anemia and the attention to and compliance with anemia monitoring.

10.
Sci Total Environ ; 685: 818-826, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31238285

RESUMO

Sorption to biofilms is thought to be a crucial process controlling the fate of trace organic contaminants in aquatic systems. The organic composition of biofilms is regarded as the determining factor in the sorption mechanism of biofilm organic carbon fractions; however, its role is not well known. Here, the sorption of phenanthrene and ofloxacin was modeled with classic and emerging organic contaminants, respectively, by comparatively investigating nine type of freshwater biofilms cultured in a river, lake, and reservoir in spring, summer, and autumn. The chemical features of the nine biofilms were analyzed using elemental analysis, infrared spectroscopy, X-ray photoelectron spectroscopy, and carbon-13 nuclear magnetic resonance. Results showed that the freshwater biofilms were aliphatic-rich natural amorphous solid substances with O-containing functional groups, and their surface polarity was significantly lower than their bulk polarity. All the isotherms of phenanthrene and ofloxacin sorption by the biofilms were linear. The organic carbon-normalized partition coefficient values for phenanthrene and ofloxacin on the nine biofilms ranged from 91.9 to 364.2 L g-1 and 3.2 to 43.2 L g-1, respectively. The van der Waals interaction between a majority of aliphatic carbon (73.4%-83.9%) in biofilms and the two sorbates was much stronger than π-π interactions between a minority of aromatic carbon (12.7%-21.7%) and sorbates. The surface polarity of the biofilms regulated polar interactions including the hydrogen bonding and electron donor-acceptor interactions. Both the aliphatic carbon and surface polarity in the biofilms enhanced the sorption of phenanthrene and ofloxacin. The sorption characteristics and mechanisms of polycyclic aromatic hydrocarbons and antibiotics on biofilms shown in our present and previous studies are different from those of other ubiquitous natural solid materials such as soils and sediments. This study provides insight into the importance of aliphatic carbon fractions of freshwater biofilms for the sorption of classic and emerging organic contaminants.


Assuntos
Biofilmes/efeitos dos fármacos , Carbono , Ofloxacino/metabolismo , Fenantrenos/metabolismo , Poluentes Químicos da Água/metabolismo , Adsorção , Biodegradação Ambiental , Água Doce , Espectroscopia de Ressonância Magnética , Ofloxacino/análise , Ofloxacino/toxicidade , Fenantrenos/análise , Fenantrenos/toxicidade , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
11.
Mikrochim Acta ; 186(7): 457, 2019 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-31218476

RESUMO

A novel ketone-functionalized carbazolic porous framework named PBPMCz is presented for fluorometric determination of p-nitroaniline (PNA). PBPMCz was prepared by FeCl3-promoted oxidative coupling polymerization of 1,3,5-tris((4-(9H-carbazol-9-yl)phenyl)methanone-1-yl)benzene. The polymer possesses a BET surface area of above 907 m2∙g-1 with a pore volume of 0.72 cm3∙g-1. Compared to the ketone-free framework, the green fluorescence of the probe PBPMCz is more strongly quenched by PNA. Figures of merit include (a) excitation/emission wavelengths of 366/540 nm; (b) a Stern-Volmer constant (Ksv) of 2.2 × 104 M-1, and (c) a detection limit of 1.1 µM. Furthermore, PBPMCz shows different quenching behaviors of PNA compared with o-nitroaniline and m-nitroaniline. The excellent performance of the fluorescent probe is ascribed to the abundant carbazole sites and ketone groups in PBPMCz. These facilitate the electron transfer and hydrogen-bonding interactions between PNA and the polymer. Graphical abstract Schematic presentation of a luminescent carbazolic porous organic framework (CzPOF) modified with keto groups. It shows ultra-sensitivity to quenching by PNA over other nitroaniline isomers.

12.
Fitoterapia ; 136: 104168, 2019 Jul.
Artigo em Francês | MEDLINE | ID: mdl-31075487

RESUMO

The Ascomycete fungus Aphanoascus fulvescens isolated from goose dung was investigated for its secondary metabolites, yielding five new indole alkaloids okaramines V-Z (1-5) and eleven known derivatives (6-16). Their structures were determined by 1D, 2D NMR spectra and HRMS data. Compounds 6, 8, 11 and 12 showed significant to moderate cytotoxicity against the mouse lymphoma cell line L5178Y with IC50 values ranging from 4.0 to 14.7 µM. Preliminary structure-activity relationships are discussed.


Assuntos
Ascomicetos/química , Alcaloides Indólicos/farmacologia , Animais , Linhagem Celular Tumoral , Alemanha , Alcaloides Indólicos/isolamento & purificação , Espectroscopia de Ressonância Magnética , Camundongos , Estrutura Molecular , Relação Estrutura-Atividade
13.
Mikrochim Acta ; 186(5): 325, 2019 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-31049723

RESUMO

Protein p300 is a transcriptional co-activator that participates in many physiological processes including cell cycle control, differentiation and apoptosis. It serves (a) as a protein bridge that links specific transcription factors to the fundamental transcription machinery, (b) as a scaffold to complete multiple transcription cofactors, and (c) as an enzyme for acetylating histone and non-histone proteins. An ultrasensitive electrochemiluminescence (ECL) immunosensor is described here that is based on the use of a magnetic glassy carbon electrode modified with tetrahedral DNA with hollow structure, graphene oxide (GO) and gold nanocrystals. The use of a GO monolayer allows for greater carrying capacity and warrants a wider outer Helmholtz plane. Strong and stable ECL signals were achieved due to antigen-antibody interaction by using the ECL probe Ru(phen)32+. This immunosensor has a response that covers the 0.005 to 80 nM p300 concentration range and has a 1 pM detection limit. It was exploited for the determination of p300 in HeLa cell lysate and (spiked) serum. Graphical abstract Schematic presentation of an ultrasensitive Faraday-cage electrochemiluminescence immunosensor toward the transcriptional co-activator p300 analysis is presented based on a graphene oxide monolayer and tetrahedral DNA-mediated signal amplification.

14.
Sci Rep ; 9(1): 7105, 2019 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-31053720

RESUMO

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

15.
Phytomedicine ; 61: 152861, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31029908

RESUMO

BACKGROUND: Nephrolithiasis is one of the most common and frequent urologic diseases worldwide. Several pathophysiological mechanisms are involved in stone formation, including oxidative stress, inflammation, apoptosis, fibrosis and autophagy. Curcumin, the predominant active component of turmeric, has been shown to have pleiotropic biological and pharmacological properties, such as antioxidant, anti-inflammatory and antifibrotic effects. PURPOSE: The current study proposed to systematically investigate the protective effects and the underlying mechanisms of curcumin in a calcium oxalate (CaOx) nephrolithiasis mouse model. METHODS: The animal model was established in male C57BL/6 mice by successive intraperitoneal injection of glyoxylate (100 mg/kg) for 1 week. Curcumin was orally given to mice 7 days before the injection of glyoxylate and for a total of 14 days at 50 mg/kg or 100 mg/kg. Bilateral renal tissue was harvested and processed for oxidative stress index detection, histopathological examinations and other analyses. RESULTS: Coadministration of curcumin could significantly reduce glyoxylate-induced CaOx deposition and simultaneous tissue injury in mouse kidneys. Meanwhile, curcumin alleviated the oxidative stress response via reducing MDA content and increasing SOD, CAT, GPx, GR and GSH levels in this animal model. Moreover, treatment with curcumin significantly inhibited apoptosis and autophagy induced by hyperoxaluria. Curcumin also attenuated the high expression of IL-6, MCP-1, OPN, CD44, α-SMA, Collagen I and collagen fibril deposition, which were elevated by hyperoxaluria. Furthermore, the results revealed that both the total expression and nuclear accumulation of Nrf2, as well as its main downstream products such as HO-1, NQO1 and UGT, were decreased in the kidneys of mice in the crystal group, while treatment with curcumin could rescue this deterioration. CONCLUSION: Curcumin could significantly alleviate CaOx crystal deposition in the mouse kidney and the concurrent renal tissue injury. The underlying mechanism involved the combination of antioxidant, anti-apoptotic, inhibiting autophagy, anti-inflammatory, and antifibrotic activity and the ability to decrease expression of OPN and CD44 through the Nrf2 signaling pathway. The pleiotropic antilithic properties, combined with the minimal side effects, make curcumin a good potential choice to prevent and treat new or recurrent nephrolithiasis.

16.
Environ Sci Pollut Res Int ; 26(17): 17351-17361, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31016586

RESUMO

As a result of the widespread use of antibiotics, a large amount of excretions from human and animals, containing antibiotic residues, is discharged into aquatic environments, leading to potential adverse effects on the ecosystems' health. These residues' impact on seasonally ice-covered rivers remains under investigated. To understand the environmental fate of antibiotics with high-detection frequencies and concentration levels, sulfamethoxazole, lincomycin, and florfenicol were used as models in the present study. A Level IV fugacity model was established and applied to a seasonally ice-covered river receiving municipal wastewater treatment plant (WWTP) effluents, the Songhua River in Northeast China. Model validation and sensitivity analysis suggested that the fugacity model could successfully simulate the monitoring concentration within an average difference of one logarithmic unit. The advection process played a major role in the transport and attenuation of the antibiotics in the ice-covered river receiving WWTP effluents. The scenario simulation indicated that increasing the targeted antibiotic concentrations in WWTP effluents to µg L-1 could keep the targeted antibiotic concentrations higher than 10 ng L-1 in the receiving river from the WWTP discharge source to 25 km downstream. This finding also demonstrates that the depth of water and ice, as well as flow velocity, play key roles in the fate of antibiotics in the ice-covered river receiving WWTP effluents. To our best knowledge, this is the first major study to combine experimental investigation with modeling to explore the environmental behaviors and fate of antibiotics in such a river.


Assuntos
Antibacterianos/análise , Monitoramento Ambiental/métodos , Eliminação de Resíduos Líquidos , Águas Residuárias/análise , Poluição da Água/estatística & dados numéricos , Animais , China , Ecossistema , Humanos , Camada de Gelo , Lincomicina/análise , Multimídia , Rios/química , Sulfametoxazol/análise , Tianfenicol/análogos & derivados , Tianfenicol/análise , Águas Residuárias/química , Poluentes Químicos da Água/análise
17.
Anal Chim Acta ; 1066: 28-35, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31027532

RESUMO

A novel mushroom-like electrochemical immunoassay for the ultrasensitive detection of histone acetyltransferase activity (HAT p300) has been established on account of the new composite graphene oxide (GO) nanolayer. The immunoassay involves immobilization of substrate peptide onto Au electrode, acetylation in lysine of substrate peptide, and the interaction between acetyl group of lysine and acetyl-antibody (AbAc) of the GO nanolayer. The GO nanolayer comprises large amounts of methylene blue molecules (MB), giving rise to large signal amplification. Only in the presence of HAT p300, an obvious electrochemical signal appears and the peak linear current is proportion to the HAT p300 concentrations ranging from 0.01 to 150 nM with a detection limit of 0.0036 nM. The great enhancement on sensitivity of the proposed mushroom-like immunosensor derives from both the constructed Faraday cage and the extended outer Helmholtz plane (OHP). Further, the immunosensor with excellent sensitivity and selectivity can be applied for the HAT p300 activity detection in Hela cell lysates, serum and urine, hinting an improved and splendid analytical performance. Briefly, this stable, simple and ultrasensitive electrochemical immunoassay has considerable promise for further applications in the HATs-interrelated epigenetic studies and drug development.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Histona Acetiltransferases/análise , Imunoensaio , Eletrodos , Ouro/química , Grafite/química , Células HeLa , Histona Acetiltransferases/metabolismo , Humanos
18.
Anal Chim Acta ; 1062: 124-130, 2019 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-30947988

RESUMO

Vibrio parahaemolyticus (VP), as a kind of harmful bacterium to human beings, its rapid and accurate detection is particularly important. Herein, we developed a simple and efficient dual-modal Faraday cage-type immunosensor for ultrasensitive detection of VP based on electrochemiluminescence (ECL) and anodic stripping voltammetry (ASV). After being captured by capture unit on magnetic glassy carbon electrodes, VP was recognized by detector unit, achieving ECL and ASV dual-modal detection. Compared with traditional sandwich-type immunosensors, this proposed immunosensor has the advantages of significant signal amplification effects, due to its distinctive Faraday cage-type structure. Benefited from it, all Ru(bpy)22+ and AgNPs labeled on the detector unit could participate in the electrode reaction and generate stronger ECL and electrochemical signals respectively. Under the optimized conditions, the linear range was from 102 to 107 CFU mL-1 with a limit of detection (LOD) of 33 CFU mL-1, and the selectivity, stability and reproducibility were satisfactory. In addition, the results of two detection methods can mutually validate each other to avoid false positive results. Moreover, this Faraday cage-type immunosensor with dual-modal detection can also be used for detection of VP in seawater samples with recoveries in the range of 96.1-107.9%, which would be a promising tool for pathogenic bacteria analysis.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Imunoensaio , Medições Luminescentes , Vibrio parahaemolyticus/isolamento & purificação , Eletrodos , Humanos
19.
Luminescence ; 34(4): 437-443, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31025821

RESUMO

Novel water-soluble green fluorescent carbon nanodots (CNs) using methacrylic acid and m-phenylenediamine as precursors were first synthesized using a one-pot hydrothermal method. Red fluorescent lanthanide complexes were prepared using lanthanide ion Eu3+ and pyridine-2,6-dicarboxylic acid. The optical properties of CNs were characterized using ultraviolet visible (UV) spectra and fluorescence spectra, microscopic morphology was characterized using transmission electron microscopy (TEM) and dynamic light scattering (DLS), and the elemental composition was characterized using Fourier transform-infrared spectroscopy (FT-IR) and X-ray photoelectron spectra (XPS). The fluorescence spectra of the lanthanide complexes were also measured. A simple strategy was developed to prepare UV light-tunable fluorescent inks and polymer hydrogels films based on CNs and lanthanide complexes. The fluorescent inks and polymer hydrogels films could be repeatedly switched between green and red fluorescence. The change of color depended on luminescence of the CNs and the lanthanide complexes under 254 and 365 nm UV light, respectively. The UV light-tunable fluorescent inks and polymer hydrogels films could enhance its anti-counterfeiting function for data and information.


Assuntos
Hidrogel de Polietilenoglicol-Dimetacrilato/química , Tinta , Elementos da Série dos Lantanídeos/química , Nanotubos de Carbono/química , Polímeros/química , Raios Ultravioleta , Fluorescência , Tamanho da Partícula , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta
20.
Artigo em Inglês | MEDLINE | ID: mdl-30818877

RESUMO

Antibiotic residues have been detected in aquatic environments worldwide. Biofilms are one of the most successful life forms, and as a result are ubiquitous in natural waters. However, the response mechanism of freshwater biofilms to the stress of various antibiotic residues is still unclear. Here, the stress of veterinary antibiotic florfenicol (FF) and fluoroquinolone antibiotic ofloxacin (OFL) on freshwater biofilms were investigated by determining the changes in the key physicochemical and biological properties of the biofilms. The results showed that the chlorophyll a content in biofilms firstly decreased to 46⁻71% and then recovered to original content under the stress of FF and OFL with high, mid, and low concentrations. Meanwhile, the activities of antioxidant enzymes, including superoxide dismutase and catalase, increased between 1.3⁻6.7 times their initial values. FF was more toxic to the biofilms than OFL. The distribution coefficients of FF and OFL binding in extracellular polymeric substances (EPS)-free biofilms were 3.2 and 6.5 times higher than those in intact biofilms, respectively. It indicated that EPS could inhibit the FF and OFL accumulation in biofilm cells. The present study shows that the EPS matrix, as the house of freshwater biofilms, is the primary barrier that resists the stress from antibiotic residues.


Assuntos
Antibacterianos/toxicidade , Biofilmes/efeitos dos fármacos , Resíduos de Drogas/toxicidade , Matriz Extracelular de Substâncias Poliméricas/química , Água Doce/química , Ofloxacino/toxicidade , Tianfenicol/análogos & derivados , China , Tianfenicol/toxicidade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA