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1.
Food Chem ; 304: 125377, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31476547

RESUMO

We devise a novel colorimetric aptasensor for multiplex antibiotics based on an ss-DNA fragment coordinately controlling gold nanoparticles (AuNPs) aggregation. The multifunctional aptamer (Apt) was elaborately designed to be adsorbed on AuNPs surfaces acting as a binding element for antibiotics and a molecular switch. Chloramphenicol (CAP) and tetracycline (TET) were selected as the model antibiotics. When one kind of antibiotics was added, the specifically recognized fragment of Apt can bind to it and dissociated, and the non-specific one coordinately controls AuNPs aggregation under high-salt conditions. Hence, different color changes of AuNPs solution can be used as the signal readout. The aptasensor exhibited remarkable selectivity and sensitivity for separate detection of TET and CAP, and the detection limits are estimated to be 32.9 and 7.0 nM, respectively. The analysis with the absorption spectroscopy and the smartphone are applied to detect antibiotics in real samples with consistent results and desirable recoveries.

2.
Artigo em Inglês | MEDLINE | ID: mdl-31727517

RESUMO

In this work, a label-free, selective, and sensitive luminescent sensing platform was established for tyrosinase (TYR) activity monitoring and its inhibitor screening using one kind of lanthanide coordination polymer nanoparticles AMP-Tb/Ag+. By taking advantage of the specific binding and redox properties of Ag+ incorporated into the AMP-Tb network and dopamine (DA) as the product of the model substrate tyramine, the enzymatic reaction and the signal change of the sensing platform was effectively linked. The cooperative effect of a weakened energy transfer from AMP to Tb3+ by altering the electronic structure of Ag+ and an efficient photoinduced election transfer (PET) process caused by dopaquinone facilitated the luminescence quenching of Tb3+. Thus, this luminescent sensing platform could be employed for quantitative evaluation of TYR activity. There was a good linear range for TYR activity from 0.08 to 0.20 U mL-1 with a low detection limit of 0.004 U mL-1. Furthermore, this assay was successfully applied to accurate determination of TYR activity in human serum samples and efficient screening of TYR inhibitors. Considering unique spectral characteristics of lanthanides along with operation simplicity and superior analytical performance, this sensing platform is very promising in clinical diagnosis and drugs screening for TYR-associated diseases.

3.
Anal Bioanal Chem ; 2019 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-31641824

RESUMO

A label-free, rapid response colorimetric aptasensor for sensitive detection of chloramphenicol (CAP) was proposed, which was based on the strategy of ssDNA-modified gold nanoparticle (AuNP) aggregation assisted by lanthanum (La3+) ions. The AuNPs generated a color change that could be monitored in the red, green, and blue and analyzed by the smartphone imaging app. La3+, as a trigger agent, strongly combined with the phosphate groups of the surface of ssDNA-AuNPs probe, which helps create AuNP aggregation and the color change of AuNPs from red to blue. On the contrary, when mixing with CAP, the aptamer (Apt) bound to CAP to form a rigid structure of the Apt-CAP complex, and La3+ attached to the phosphate groups of the complex, which prevented the aptamer from binding to the surface of the AuNPs. As a result, the color of the AuNPs changed to violet-red. Finally, UV-vis absorption spectroscopy and the smartphone imaging app were employed to determine CAP with a lower detection limit of 7.65 nM and 5.88 nM, respectively. The proposed strategy featuring high selectivity and strong anti-interference ability for detection of CAP in practical samples was achieved. It is worth mentioning that the simple and portable colorimetric aptasensor will be used for facilitating on-site detection of food samples.

4.
Mutat Res ; 846: 403072, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31585629

RESUMO

A series of genotoxicity assessments were conducted on male Sprague Dawley rats treated with Auramine O (AO) to establish a multiple-endpoint assay. The rat liver micronucleus assay, in combination with the comet assay, peripheral blood micronucleus assay, and erythrocyte Pig-a assay in the same experiment, comprehensively assess the genotoxicity of AO. Rats were orally exposed to 0, 100, 200, or 400 mg/kg/day AO for 15 consecutive days. The blood was sampled on Days -1 and 15 for the erythrocyte Pig-a assay and peripheral blood micronucleus assay. Livers were sampled on Day 15 for the liver micronucleus assay and comet assay. Based on the liver micronucleus assay and liver comet assay, AO induced a significant dose-related increase of micronucleated hepatocyte frequencies, and tail DNA percentages, respectively in the middle- and high-dose groups. On the blood micronucleus test and Pig-a assay, no significant increases were observed for the micronucleated reticulocyte frequencies, mutant erythrocyte frequencies (RBCCD59-) or mutant reticulocyte frequencies (RETCD59-) at any of the time points studied. In conclusion, using a multiple-endpoint genotoxicity assay method can reduce the number of experimental animals, boost the efficiency of the experiment, and improve the accuracy of investigations of genotoxicity.

5.
Environ Mol Mutagen ; 2019 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-31443125

RESUMO

A newly developed in vivo Pig-a gene mutation assay displays great potential for integration into genotoxicity tests. To obtain more evidence for application of the Pig-a assay, we integrated this assay, micronucleus test in peripheral blood (MN-pb test) and bone marrow (MN-bm test), as well as a Comet assay into a transgenic RasH2 mice carcinogenicity study. Fourteen male RasH2 mice and five wild-type (WT) mice were treated with a strong mutagen aristolochic acid I at a dose of 5 mg/kg/day for 4 consecutive weeks. Mice recovered in 5 weeks. Peripheral bloods were collected for Pig-a assay, MN-pb test, and Comet assay at several time points, while bone marrow and target organs were harvested for the MN-bm test and pathological diagnosis after mice were euthanized. Finally, 13 of the 14 RasH2 mice developed squamous cell carcinomas in the forestomach, while there were no carcinomas in the WT mice. Pig-a mutant frequencies (MFs) consecutively increased throughout the study to a maximum value of approximately 63-fold more than background. These frequencies were relative to the incidence, size, and malignant degree of tumors. Micronucleated reticulocytes increased from Day 1 to Day 49, before returning to background levels. No positive responses were observed in either the MN-bm test or the Comet assay. Results suggested that, when compared with the other two tests, the Pig-a assay persistently contributed to sustaining MFs, enhanced detection sensitivity due to the accumulation of Pig-a mutations, and demonstrated better predictability for tumorigenicity. Environ. Mol. Mutagen. 2019. © 2019 Wiley Periodicals, Inc.

6.
Mikrochim Acta ; 186(7): 467, 2019 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-31240491

RESUMO

A colorimetric assay is described for determination of cytosine-rich ssDNA at physiological pH values. The working principle is based on (a) Ag(I) ion-induced formation of an i-motif structure, and (b) glucose oxidase-controlled growth of gold nanoparticles (AuNPs). The combination between Ag+ and cytosine-rich DNA can modulate the generation of H2O2 resulting from enzyme catalyzed glucose oxidation. Depending on the amount of H2O2 formed, the solution containing the AuNPs will turn red in the presence of cytosine-rich ssDNA but blue in the absence of such DNA if Ag+ is added before the formation of the red AuNPs. Upon addition of C-DNA at different concentrations, the peak shift (Δλ) of the AuNP solution relative to the SPR peak position (560 nm) in the absence of C-DNA is taken as the signal readout. The method shows a good linear response toward C-DNA over the range 10-200 nM with a detection limit of 2.7 nM. It may also be performed visually. The photometric assay is highly sensitive, specific, and rapid. The method is particularly attractive in terms of applications such as in human serum analysis, a colorimetric logic gate, and the calculation of binding constants for the interaction between Ag+ and glucose oxidase (GOx), and between Ag+ and cytosine-rich ssDNAs. Graphical abstract Schematic presentation of colorimetric detection of cytosine (C)-rich ssDNA (C-DNA) based on the modulation of the glucose oxidase (GOx)-catalyzed growth of gold nanoparticles (AuNPs) with Ag+ as the enzyme inhibitor.

7.
Spectrochim Acta A Mol Biomol Spectrosc ; 214: 233-238, 2019 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-30785042

RESUMO

We report a highly sensitive fluorescent probe based on p-dimethylaminobenzoyl derivatives (probe L) for the detection of Cu2+ and Zn2+. In this work, the probe L exhibited a fluorescent turn-on sensing model to Cu2+ and Zn2+ with a distinct fluorescent color change from colorless to green and yellow respectively. Probe L exhibited high selectivity as a fluorescent Cu2+/Zn2+ probe with a limit of detection (LOD) of 45 nM/17 nM. The results of 1H NMR titrations revealed that the response of L to Cu2+ and Zn2+ was triggered by the interaction of the thiophene unit and the metal ion. Furthermore, the fluorescence titrations and Job's plot curves displayed the binding ratio of 1:2 for Cu2+ and 1:1 for Zn2+ metal-L complex formation respectively. Density functional theory calculation also demonstrated the possibility of molecular luminescence and the process of metal-L complex formation. Additionally, fluorescent test strips have been prepared for convenient detection of Cu2+ and Zn2+, which means the convenient and rapid assay in real samples can be achieved.


Assuntos
Cobre/metabolismo , Corantes Fluorescentes , Zinco/metabolismo , Cobre/química , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/química , Corantes Fluorescentes/farmacologia , Células HeLa , Humanos , Limite de Detecção , Espectrometria de Fluorescência , Zinco/química
8.
Curr Biol ; 28(24): 3948-3959.e4, 2018 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-30528578

RESUMO

Orchestration of sleep and feeding behavior is essential for organismal health and survival. Although sleep deprivation promotes feeding and starvation suppresses sleep, the underlying neural mechanisms remain largely unknown. Here, we showed that starvation in mice potently promoted arousal and activated calretinin neurons (CR+) in the paraventricular thalamus (PVT). Direct activation of PVTCR+ neurons promoted arousal, and their activity was necessary for starvation-induced sleep suppression. Specifically, the PVTCR+-bed nucleus of the stria terminalis (BNST) circuit rapidly initiated arousal. Selective inhibition of BNST-projecting PVT neurons opposed arousal during starvation. Taken together, our results define a cell-type-specific neural circuitry modulating starvation-induced arousal and coordinating the conflict between sleeping and feeding.


Assuntos
Nível de Alerta/fisiologia , Privação de Alimentos , Neurônios/fisiologia , Núcleos Septais/fisiologia , Animais , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Vias Neurais/fisiologia , Inanição/fisiopatologia , Tálamo/fisiologia
9.
J Psychiatr Res ; 105: 86-94, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30212728

RESUMO

The pathophysiology of neuropsychiatric disorders is unclear. Increasing evidence has suggested maternal immune system dysregulation may be implicated in offspring's early brain development and related to an increased risk of neuropsychiatric disorders in offspring. The primary objective of this meta-analysis was to investigate the association of maternal CRP and cytokine levels with offspring's neuropsychiatric disorders. We identified relevant studies following a search of PubMed, Web of Science, EMbase database between January 1971 and February 2018. A meta-analysis was performed on studies which reported the association of prenatal maternal peripheral blood concentrations of CRP and cytokines with offspring's neuropsychiatric disorders. Results were reported according to PRISMA statement. Fifteen studies (six for maternal CRP, nine for maternal cytokines) were included in the meta-analysis, of which 80% were of high methodological quality. Random-effect meta-analysis showed that increasing maternal CRP (OR = 1.31, 95% CI 1.11-1.55, SMD = 0.15, 95% CI 0.06-0.24, P < 0.01), pro-inflammatory cytokine interleukin (IL)-8 (OR = 1.64, 95% CI 1.06-2.55, SMD = 0.27, 95% CI 0.03-0.52, P = 0.03) and anti-inflammatory cytokine IL-10 (OR = 2.16, 95% CI 1.30-3.59, SMD = 0.43, 95% CI 0.14-0.71, P < 0.01) were significantly associated with schizophrenia in offspring. The finding of our meta-analysis has identified significantly altered maternal CRP and cytokine concentrations in schizophrenia, strengthening evidence of maternal immune system dysregulation in neuropsychiatric disorders where inflammatory signals dominate.

10.
Anal Chim Acta ; 1034: 144-152, 2018 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-30193628

RESUMO

In our study, the carbon nanodots (CDs) were synthesized by one-step solvothermal method using resorcinol as the only presusor. The obtained CDs contained abundant unsaturated oxygen-containing groups resulting from the surface oxidation. A novel, simple, and real-time fluorescent assay for the detection of water in various organic solvents was thus established by reducing the surface oxidation states. Excellent reversibility can be readily achieved by the external stimulus water and N,N'-dicyclohexylcarbodiimide (DCC). The water-induced sensitive (limit of detection = 0.006%, v/v, in ethanol) and ultrafast (<1 s) response in emission properties was capable of water determination in spirit samples in both solution and solid-state paper test strips.

11.
Spectrochim Acta A Mol Biomol Spectrosc ; 204: 568-575, 2018 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-29975918

RESUMO

In this work, a simple and easily synthesized Schiff-based derivative colorimetric and fluorescent sensor (1), 4-dimethylamino-benzoic acid (2-imidazole formaldehyde)-hydrazide, was obtained for the detection of Cu2+ and S2-. The compound 1 exhibited dual spectral responses to Cu2+, that is, vivid color change and fluorescence enhancement in the presence of Cu2+. The detection limits were valued as 0.46 µM and 15 nM according to absorption and fluorescent response, respectively. Both of them are below the World Health Organization (WHO) guidelines for drinking water (31.5 µM). In addition, the ensemble (1-Cu2+) selectively and sensitively detected a low concentration of S2-. As the addition of S2- instantly removed Cu2+ from the ensemble (1-Cu2+) resulting in a color change from yellow to colorless and a "turn-off" fluorescent response. The detection limit for S2- was estimated as 0.12 µM (from fluorescent method) and 0.68 µM (from absorption method), respectively, each of which was also lower than the maximum allowable level of S2- (15 µM) in drinking water defined by the WHO. The binding process was confirmed via UV-vis absorption, fluorescence measurements, 1H NMR, mass spectroscopy and density functional theory calculation. What's more, successful practical application of test paper is used to inspect the S2- which means the convenient and rapid assay in real samples can be achieved.


Assuntos
Colorimetria/métodos , Cobre/análise , Corantes Fluorescentes/análise , Enxofre/análise , Poluentes Químicos da Água/análise , Água Potável/química , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos Testes
12.
Mikrochim Acta ; 185(6): 300, 2018 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-29766346

RESUMO

A polydopamine-based molecularly imprinted polymer was deposited on the surface of magnetite (ferroferric oxide) nanoparticles (Fe3O4@PDA MIPs) and is shown to be an efficient and fairly specific sorbent for the extraction of various ochratoxins. The MIPs were characterized by IR spectroscopy and transmission electron microscopy. The adsorption capacities, evaluated through the langmuir adsorption isotherm model, are 1.8, 0.23 and 0.17 mg·g-1 for ochratoxin A, ochratoxin B and ochratoxin C, respectively. Parameters such as the amount of magnetic MIPs, pH value, time for ultrasonication, elution solvent and volume were optimized. Following desorption from the MIP with acetonitrile, the ochratoxins were quantified by HPLC with fluorometric detection. Under optimal experimental conditions, the calibration plots are linear in the range of 0.01-1.0 ng·mL-1 of OTA, 0.02-2.0 ng·mL-1 of OTB, and 0.002-0.2 ng·mL-1 of OTC. The LODs are between 1.8 and 18 pg·mL-1, and the recoveries from spiked samples are 71.0% - 88.5%, with RSDs of 2.3-3.8% in case of rice and wine samples. The MIPs can be re-used for at least 7 times. Graphical abstract Schematic of the preparation of a magnetic molecularly imprinted polymer based on self-polymerization of dopamine in weakly alkaline solution. Ochratoxins are recognized owing to homologous cavities in the MIPs, and quantified by HPLC after desorption with acetonitrile.

13.
Anal Chem ; 90(11): 7004-7011, 2018 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-29701058

RESUMO

Lanthanide-based luminescent sensors have been widely used for the detection of the anthrax biomarker dipicolinic acid (DPA). However, mainly based on DPA sensitization to the lanthanide core, most of them failed to realize robust detection of DPA in bacterial spores. We proposed a new strategy for reliable detection of DPA by perturbing a tandem energy transfer in heterobinuclear lanthanide coordination polymer nanoparticles simply constructed by two kinds of lanthanide ions, Tb3+ and Eu3+, and guanosine 5'-monophosphate. This smart luminescent probe was demonstrated to exhibit highly sensitive and selective visual luminescence color change upon exposure to DPA, enabling accurate detection of DPA in complex biosystems such as bacterial spores. DPA release from bacterial spores on physiological germination was also successfully monitored in real time by confocal imaging. This probe is thus expected to be a powerful tool for efficient detection of bacterial spores in responding to anthrax threats.

14.
Spectrochim Acta A Mol Biomol Spectrosc ; 192: 174-180, 2018 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-29136582

RESUMO

In this study, we have developed a method for rapid, highly efficient and selective detection of melamine. The negatively charged citrate ions form an electrostatic layer on gold nanoparticles (AuNPs) and keep the NPs dispersed and stable. When citrate-capped AuNPs were further modified with Triton X-100, it stabilized the AuNPs against the conditions of high ionic strength and a broad pH range. However, the addition of melamine caused the destabilization and aggregation of NPs. This may be attributed to the interaction between melamine and the AuNPs through the ligand exchange with citrate ions on the surface of AuNPs leading Triton X-100 to be removed. As a result, the AuNPs were unstable, resulting in the aggregation. The aggregation induced a wine red-to-blue color change, and a new absorption peak around 630nm appeared. Triton X-100-AuNPs could selectively detect melamine at the concentration as low as 5.1nM. This probe was successfully applied to detect melamine in milk. Furthermore, paper-based quantitative detection system using this colorimetric probe was also demonstrated by integrating with a smartphone.


Assuntos
Colorimetria/métodos , Ouro/química , Nanopartículas Metálicas/química , Leite/química , Octoxinol/química , Papel , Triazinas/análise , Animais , Cor , Espectrofotometria Ultravioleta
15.
Analyst ; 142(21): 4106-4115, 2017 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-28980671

RESUMO

This work presents a novel and facile strategy for the fabrication of gold-platinum bimetallic nanoclusters (Au-PtNCs) with adjustable Au/Pt molar ratios by a one-pot synthetic route. It was unexpectedly found that the prepared Au-PtNCs with an optimal Au/Pt molar ratio (1 : 1) could exhibit greatly enhanced peroxidase-like catalytic activity and chemical stability toward harsh conditions due to the synergistic effect of the two atoms, in contrast with pure AuNCs. These prominent advantages render Au-PtNCs capable of sensitive and selective colorimetric detection of glucose by means of a NCs-glucose oxidase (GOx) cascade-catalyzed system using 3,3',5,5'-tetramethylbenzidine (TMB) as a chromogenic substrate. This assay can be used not only for visual detection of glucose by the naked eye but for reliable and convenient quantification in the range from 5 to 55 µM with a detection limit of 2.4 µM. Importantly, to widen the application of point-of-care testing (POCT) of glucose to biomedical diagnosis, an integrated agarose hydrogel-based sensing platform comprising NCs, GOx and TMB was rationally designed. It was demonstrated that this sensing platform could serve as a reagentless and instrument-free platform for direct visualization of glucose with different levels in human serum, as the results were in good accordance with those obtained from a free NC-involved detection system as well as from a commercial blood glucometer.

16.
Methods Appl Fluoresc ; 5(2): 024014, 2017 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-28475492

RESUMO

A new Al3+-specific fluorescent probe NQ was designed and synthesized from 2-hydroxy-1-naphthaldehyde and 2-aminoquinoline. Upon the addition of Al3+, the fluorescent intensity of NQ was significantly enhanced compared with other examined metal ions in aqueous solution. The result of a Job's plot indicated the formation of a 1:1 complex between the probe and Al3+, and the possible binding mode of the system between NQ and Al3+ was clarified by IR analysis and 1H NMR titration. Moreover, other metal ions examined had little effect on the detection of Al3+. The detection limit of NQ for Al3+ detection was 1.98 µM, which is lower than the level (7.4 µM) in drinking water defined by the World Health Organization. In addition, the fluorescent probe NQ could be recyclable simply through treatment with a proper reagent such as F-, and could also be used for the detection of Al3+ in real samples.

17.
J Sep Sci ; 40(11): 2431-2437, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28387467

RESUMO

A new method based on cetylpyridinium chloride coated ferroferric oxide/silica magnetic microspheres as an efficient solid-phase adsorbent was developed for the extraction and enrichment of ochratoxin A. The determination of ochratoxin A was obtained by high-performance liquid chromatography with fluorescence detection. In the presence of cetylpyridinium chloride, the adsorption capacity of ferroferric oxide/silica microspheres was 5.95 mg/g for ochratoxin A. The experimental parameters were optimized, including the amounts of ferroferric oxide/silica microspheres (20 mg) and cetylpyridinium chloride (0.18 mL, 0.5 mg/mL), pH value of media (9), ultrasonic time (5 min), elution solvent and volume [2(1 + 1) mL (washed twice, 1 mL each time) 1% acetic acid acetonitrile]. Under optimal experiment conditions, ochratoxin A had good linearity in the range of 2.5-250.0 ng/L in water samples with correlation coefficient of the calibration curve 0.9995. The limit of detection for ochratoxin A was 0.83 ng/L, and the recoveries were 89.8-96.8% with the relative standard deviation of 1.5-3.5% in environmental water samples. Furthermore, ferroferric oxide/silica microspheres show excellent reusability during extraction procedures for no less than six times.


Assuntos
Ocratoxinas/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Cetilpiridínio , Cromatografia Líquida de Alta Pressão , Óxido Ferroso-Férrico , Microesferas , Dióxido de Silício , Extração em Fase Sólida
18.
Anal Chim Acta ; 967: 64-69, 2017 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-28390487

RESUMO

Glutathione (GSH), the most abundant biothiol in cells, not only plays a pivotal role in protective and detoxifying functions of the cell, but also serves as a very important mediator in many cellular functions. Especially, the difference of GSH level between cancer cells and normal cells is regarded as one of most important physiological parameters for cancer diagnosis. It is thereby extremely necessary to develop a simple, sensitive, and reliable analytical method for detection of GSH in cells. On the basis of the inhibition effect of GSH on the peroxidase-like activity of GSH stabilized gold nanoclusters, here a novel and facile strategy for colorimetric detection of cellular GSH level was well established. In this sensing system, GSH can effectively inhibit the oxidation of peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) to produce a blue colored product. Under the optimized conditions, the absorbance at 652 nm against GSH concentration shows a linear relationship within a range from 2 to 25 µM with detection limit of 420 nM. This excellent property allows our approach to be used to accurately evaluate the cellular GSH levels, and it is revealed that the overall GSH level in cancer cells was much higher than that in normal cells. The presented assay will enable a powerful tool for identifying cancer cells in a simple manner for biomedical diagnosis associated with GSH.


Assuntos
Colorimetria , Glutationa/análise , Ouro , Nanopartículas Metálicas/química , Linhagem Celular Tumoral , Humanos , Limite de Detecção , Neoplasias/diagnóstico , Oxirredução , Peroxidase , Células THP-1
19.
Nanoscale Res Lett ; 12(1): 103, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28209025

RESUMO

Photonic crystal (PC)-based devices have been widely used since 1990s, while PC has just stepped into the research area of nanofluidic. In this paper, photonic crystal had been used as a complementary metal oxide semiconductors (CMOS) compatible part to create a nanofluidic structure. A nanofluidic structure prototype had been fabricated with CMOS-compatible techniques. The nanofluidic channels were sealed by direct bonding polydimethylsiloxane (PDMS) and the periodic gratings on photonic crystal structure. The PC was fabricated on a 4-in. Si wafer with Si3N4 as the guided mode layer and SiO2 film as substrate layer. The higher order mode resonance wavelength of PC-based nanofluidic structure had been selected, which can confine the enhanced electrical field located inside the nanochannel area. A design flow chart was used to guide the fabrication process. By optimizing the fabrication device parameters, the periodic grating of PC-based nanofluidic structure had a high-fidelity profile with fill factor at 0.5. The enhanced electric field was optimized and located within the channel area, and it can be used for PC-based nanofluidic applications with high performance.

20.
Spectrochim Acta A Mol Biomol Spectrosc ; 173: 264-269, 2017 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-27673495

RESUMO

A new p-dimethylaminobenzamide derivative based compound BDIH has been synthesized. Cu2+ turned on the fluorescence of compound BDIH with a 1:2 binding stoichiometry. The fluorescent color of compound BDIH shows an evident change from colorless to bright blue upon the addition of Cu2+, which could be visibly detected by the naked eye under UV light at 365nm. More importantly, the detection limit was found to be 0.64nM which is far lower than the maximal allowed concentration of the WHO limit (31.5µM) for drinking water. This selective "turn-on" fluorescence sensor was used to identify Cu2+ in living cells using confocal fluorescence microscopy, indicating that compound BDIH has a potential application for selective detection of Cu2+ in organism.


Assuntos
Benzaldeídos/química , Benzoatos/química , Cobre/análise , Hidrazinas/química , Indóis/química , Espectrometria de Fluorescência/métodos , Carcinoma Hepatocelular/química , Linhagem Celular Tumoral , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/química , Humanos , Limite de Detecção , Neoplasias Hepáticas/química , Espectroscopia de Ressonância Magnética , Imagem Molecular/métodos , Sensibilidade e Especificidade , Espectrofotometria Ultravioleta
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