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1.
Sci Total Environ ; 792: 148493, 2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34465043

RESUMO

Dissolved organic matter (DOM) in wet weather overflows (WWFs) of storm drainage systems mainly originates from anthropogenic sources, such as paved runoff, illegally discharged domestic sewage and the retained sediment. This study provides a promising method to quantitatively apportion the WWF DOM of storm drainage systems using degradation potential index (DPI) and end member mixing (EMM) model. DPI is derived from excitation-emission matrix parallel factor analysis (EEM-PARAFAC), which can endow the end members and itself of WWF DOM with numerical features, and thus help quantify the source contributions of WWF DOM in EMM model. Findings show that (1) DPI was a reliable tool in the quantitative source apportionment of WWF DOM, owing to its features of small variance within source and large variances between sources; (2) DPI combined with EMM model could help identify the factors that induce significant impacts on the source contributions of WWF DOM, such as the storm pumping discharge and antecedent dry days in our case study; (3) the identified factors could guide the development of effective strategies for WWF DOM control, e.g. sediment management in our case.


Assuntos
Esgotos , Tempo (Meteorologia) , Análise Fatorial , Espectrometria de Fluorescência
2.
J Environ Sci (China) ; 108: 8-21, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34465439

RESUMO

Dissolved organic matter (DOM) plays a major role in ecological systems and influences the fate and transportation of many pollutants. Despite the significance of DOM, understanding of how environmental and anthropogenic factors influence its composition and characteristics is limited, especially in urban stormwater runoff. In this article, the chemical properties (pollutant loads, molecular weight, aromaticity, sources, and molecular composition) of DOM in stormwater extracted from three typical end-members (traffic, residential, and campus regions) were characterized by UV-visible (UV-vis) spectroscopy, excitation-emission matrix spectroscopy combined with parallel factor analysis (EEM-PARAFAC), and ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). There are three findings: (1) The basic properties of DOM in stormwater runoff varied obviously from three urban fields, and the effect of initial flush was also apparent. (2) The DOM in residential areas mainly came from autochthonous sources, while allochthonous sources primarily contributed to the DOM in traffic and campus areas. However, it was mainly composed of terrestrial humic-like components with CHO and CHON element composition and HULO and aliphatic formulas. (3) The parameters characterizing DOM were primarily related to terrestrial source and aromaticity, but their correlations varied. Through the combination of optical methods and UPLC-Q-TOF spectrometry, the optical and molecular characteristics of rainwater are effectively revealed, which may provide a solid foundation for the classification management of stormwater runoff in different urban regions.


Assuntos
Ecossistema , Análise Fatorial , Espectrometria de Fluorescência
3.
Nanoscale ; 13(32): 13835-13844, 2021 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-34477658

RESUMO

Herbal medicines are potential candidates for the treatment of various diseases, but their medication safety remains poorly regulated. Current screening methods for the herbal medicine-induced nephrotoxic effects include histological and serological assessments, which often fail to reflect the kidney dysfunction instantly. Here we report a ratiometric fluorescence approach for the rapid and facile screening of drug-induced acute kidney injury using chromophore-modified gold nanoclusters. These gold nanoclusters are highly sensitive to reactive oxygen species (ROS), with a detection limit of 14 nM for ˙OH. After passing through the glomerular filtration barrier, the gold nanocluster-based probes can quantify the fluctuation of the ROS level in the kidneys and evaluate the risk of drug-induced nephrotoxicity. We further employed nephrotoxic triptolide as the model drug and the screening of drug-induced early renal injury was demonstrated using the nanoprobes, which is unattainable by conventional diagnostic approaches. Our fluorescent probes also allow the identification of other nephrotoxic components from herbal medicine such as aristolochine, providing a high-throughput strategy for the screening of herbal supplement-induced nephrotoxicity.


Assuntos
Nanopartículas Metálicas , Preparações Farmacêuticas , Corantes Fluorescentes , Ouro , Nanopartículas Metálicas/toxicidade , Espectrometria de Fluorescência
4.
Nanoscale ; 13(31): 13487-13496, 2021 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-34477753

RESUMO

Carbon dots are biocompatible nanoparticles suitable for a variety of biomedical applications. Careful selection of carbon dot precursors and surface modification techniques has allowed for the development of carbon dots with strong near-infrared fluorescence emission. However, carbon dots that provide strong fluorescence contrast would prove even more useful if they were also responsive to stimuli. In this work, endogenous bile pigments bilirubin (BR) and biliverdin (BV) were used for the first time to synthesize stimuli-responsive carbon dots (BR-CDots and BV-CDots respectively). The precursor choice lends these carbon dots spectroscopic characteristics that are enzyme-responsive and pH-responsive without the need for surface modifications post-synthesis. Both BV- and BR-CDots are water-dispersible and provide fluorescence contrast, while retaining the stimuli-responsive behaviors intrinsic to their precursors. Nanoparticle Tracking Analysis revealed that the hydrodynamic size of the BR-CDots and BV-CDots decreased with exposure to bilirubin oxidase and biliverdin reductase, respectively, indicating potential enzyme-responsive degradation of the carbon dots. Fluorescence spectroscopic data demonstrate that both BR-CDots and BV-CDots exhibit changes in their fluorescence spectra in response to changes in pH, indicating that these carbon dots have potential applications in pH sensing. In addition, BR-CDots are biocompatible and provide near-infrared fluorescence emission when excited with light at wavelengths of 600 nm or higher. This work demonstrates the use of rationally selected carbon sources for obtaining near-infrared fluorescence and stimuli-responsive behavior in carbon dots that also provide strong fluorescence contrast.


Assuntos
Nanopartículas , Pontos Quânticos , Pigmentos Biliares , Carbono , Espectrometria de Fluorescência
5.
Anal Chem ; 93(33): 11634-11640, 2021 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-34378382

RESUMO

Exploring the ratiometric fluorescence biosensing of DNA-templated biemissive silver nanoclusters (AgNCs) is significant in bioanalysis, yet the design of a stimuli-responsive DNA device is a challenge. Herein, using the anti-digoxin antibody (anti-Dig) with two identical binding sites as a model, a tweezer-like DNA architecture is assembled to populate fluorescent green- and red-AgNCs (g-AgNCs and r-AgNCs), aiming to produce a ratio signal via specific recognition of anti-Dig with two haptens (DigH). To this end, four DNA probes are programmed, including a reporter strand (RS) dually ended with a g-/r-AgNC template sequence, an enhancer strand (ES) tethering two same G-rich tails (G18), a capture strand (CS) labeled with DigH at two ends, and a help strand (HS). Initially, both g-AgNCs and r-AgNCs wrapped in the intact RS are nonfluorescent, whereas the base pairing between RS, ES, CS, and HS resulted in the construction of DNA mechanical tweezers with two symmetric arms hinged by a rigid "fulcrum", in which g-AgNCs are lighted up due to G18 proximity ("green-on"), and r-AgNCs away from G18 are still dark ("red-off"). When two DigHs in proximity recognize and bind anti-Dig, the conformation switch of these tweezers resultantly occurs, taking g-AgNCs away from G18 for "green-off" and bringing r-AgNCs close to G18 for "red-on". As such, the ratiometric fluorescence of r-AgNCs versus g-AgNCs is generated in response to anti-Dig, achieving reliable quantization with a limit of detection at the picomolar level. Based on the fast stimulated switch of unique DNA tweezers, our ratiometric strategy of dual-emitting AgNCs would provide a new avenue for a variety of bioassays.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Anticorpos , DNA , Fluorescência , Prata , Espectrometria de Fluorescência
6.
Int J Mol Sci ; 22(16)2021 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-34445400

RESUMO

Alternariol (AOH) is an emerging mycotoxin produced by Alternaria molds. It occurs as a contaminant e.g., in oilseeds, cereals, grapes, and tomatoes. Chronic exposure to AOH may cause genotoxic and endocrine disruptor effects. Our recent studies demonstrated that the fluorescence signal of AOH can be strongly affected by the environmental pH as well as by the presence of serum albumin or cyclodextrins. In the current study, we aimed to characterize the most optimal circumstances regarding the highly sensitive fluorescent detection of AOH. Therefore, the further detailed investigation of the microenvironment on the fluorescence signal of the mycotoxin has been performed, including the effects of different buffers, organic solvents, detergents, and cations. Organic solvents (acetonitrile and methanol) caused only slight increase in the emission signal of AOH, while detergents (sodium dodecyl sulfate and Triton-X100) and Ca2+ induced considerably higher enhancement in the fluorescence of the mycotoxin. In addition, Mg2+ proved to be a superior fluorescence enhancer of the AOH. Spectroscopic and modeling studies suggest the formation of low-affinity AOH-Mg2+ complexes. The effect of Mg2+ was also tested in two HPLC assays: Our results show that Mg2+ can considerably increase the fluorescence signal of AOH even in a chromatographic system.


Assuntos
Alternaria/química , Lactonas/análise , Magnésio/química , Acetonitrilas/química , Cromatografia Líquida de Alta Pressão , Concentração de Íons de Hidrogênio , Lactonas/química , Metanol/química , Conformação Molecular , Estrutura Molecular , Octoxinol/química , Dodecilsulfato de Sódio/química , Espectrometria de Fluorescência
7.
Analyst ; 146(17): 5357-5361, 2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34333580

RESUMO

Nitrogen doped carbon dots (N-CDs) were synthesized by a one-step hydrothermal method with dopamine and ethylenediamine. The as-prepared N-CDs were characterized via transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), fluorescence spectrophotometer, UV-Vis spectrophotometry and Fourier transform infrared spectroscopy (FTIR). The average particle dimension of the as-prepared N-CDs was 2.68 nm, and the best excitation and emission wavelengths were 405 nm and 535 nm, separately. N-CDs exhibits excellent selectivity and sensitivity to detect the curcumin (Cur), attaining a wider linear range of 97.5 nM-67.9 µM and a limit of detection (LOD) of as low as 94 nM. Interestingly, N-CDs can also give responsive signals of a visible colour change (yellow to red). Moreover, a novel fluorescent/colorimetric dual-mode method has been successfully employed for the determination of Cur in real samples with good recoveries (94%-110%) and precision (RSD = 0.3-2.9%).


Assuntos
Curcumina , Pontos Quânticos , Carbono , Colorimetria , Corantes Fluorescentes , Nitrogênio , Espectrometria de Fluorescência
8.
Sensors (Basel) ; 21(16)2021 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-34450980

RESUMO

Copper (II) ions have been shown to greatly improve the chemical stability and peroxidase-like activity of gold nanoclusters (AuNCs). Since the affinity between Cu2+ and pyrophosphate (PPi) is higher than that between Cu2+ and AuNCs, the catalytic activity of AuNCs-Cu2+ decreases with the introduction of PPi. Based on this principle, a new colorimetric detection method of PPi with high sensitivity and selectivity was developed by using AuNCs-Cu2+ as a probe. Under optimized conditions, the detection limit of PPi was 0.49 nM with a linear range of 0.51 to 30,000 nM. The sensitivity of the method was three orders of magnitude higher than that of a fluorescence method using AuNCs-Cu2+ as the probe. Finally, the AuNCs-Cu2+ system was successfully applied to directly determine the concentration of PPi in human urine samples.


Assuntos
Ouro , Nanopartículas Metálicas , Colorimetria , Cobre , Difosfatos , Corantes Fluorescentes , Humanos , Limite de Detecção , Peroxidase , Peroxidases , Espectrometria de Fluorescência
9.
Sensors (Basel) ; 21(16)2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-34451041

RESUMO

An indole-based fluorescent chemosensor IH-Sal was synthesized to detect Zn2+. IH-Sal displayed a marked fluorescence increment with Zn2+. The detection limit (0.41 µM) of IH-Sal for Zn2+ was greatly below that suggested by the World Health Organization. IH-Sal can quantify Zn2+ in real water samples. More significantly, IH-Sal could determine and depict the presence of Zn2+ in zebrafish. The detecting mechanism of IH-Sal toward Zn2+ was illustrated by fluorescence and UV-visible spectroscopy, DFT calculations, 1H NMR titration and ESI mass.


Assuntos
Peixe-Zebra , Zinco , Animais , Corantes Fluorescentes , Indóis , Espectrometria de Fluorescência , Água
10.
Langmuir ; 37(33): 10223-10232, 2021 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-34379978

RESUMO

Regarding the outbreak of the SARS Cov-2 virus pandemic worldwide, it seems necessary to provide new diagnostic methods to combat the virus. A fluorescence CdTe quantum dots-DNA (QDs-DNA) nanosensor was prepared for efficient detection of a specific target complementary DNA or RNA from the SARS Cov-2 virus using FRET experiment via forming a classic "sandwich" structure. The sequence of the complementary DNA (target DNA) is planned based on a substantial part of the SARS Cov-2 virus genome, and oligonucleotides of QDs-DNA nanoprobe are designed to complement it. The water-soluble CdTe QDs-DNA was prepared by replacing the thioglycolic acid (TGA) on the surface of QDs with capture DNA (thiolated DNA) through a ligand-exchange method. Subsequently, with the addition of complementary (target DNA) and quencher DNA (BHQ2-labeled DNA) into the QDs-DNA conjugates, sandwiched hybrids were formed. The resulting assembly brings the BHQ2-labeled DNA (as the acceptor), and the QDs (as the donor) into proximity, leading to quenching of fluorescence emission from the donor QDs through the FRET mechanism. In other words, a simple, highly sensitive, selective, and rapid approach was introduced to detect complementary DNA sequence from a specific part of the SARS Cov-2 virus genome with a detection limit of 2.52 × 10-9 mol L-1. Furthermore, the planned nanosensor was well used for the detection of RNA from SARS Cov-2 viruses in real samples with satisfactory analytical results, and the outcomes were compared with RT-PCR (Reverse Transcription Polymerase Chain Reaction) as the well-known standard method.


Assuntos
Compostos de Cádmio , Pontos Quânticos , Síndrome Respiratória Aguda Grave , DNA , Humanos , Espectrometria de Fluorescência , Telúrio
11.
J Phys Chem Lett ; 12(32): 7859-7865, 2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-34382803

RESUMO

Fluorescence-encoded vibrational spectroscopy has become increasingly more popular by virtue of its high chemical specificity and sensitivity. However, current fluorescence-encoded vibrational spectroscopy methods lack sensitivity in the low-frequency region, which if addressed could further enhance their capabilities. Here, we present a method for highly sensitive low-frequency fluorescence-encoded vibrational spectroscopy, termed fluorescence-encoded time-domain coherent Raman spectroscopy (FLETCHERS). By first exciting molecules into vibrationally excited states and then promoting the vibrating molecules to electronic states at varying times, the molecular vibrations can be encoded onto the emitted time-domain fluorescence intensity. We demonstrate the sensitive low-frequency detection capability of FLETCHERS by measuring vibrational spectra in the lower fingerprint region of rhodamine 800 solutions as dilute as 250 nM, which is ∼1000 times more sensitive than conventional vibrational spectroscopy. These results, along with further improvement of the method, open up the prospect of performing single-molecule vibrational spectroscopy in the low-frequency region.


Assuntos
Corantes Fluorescentes/química , Rodaminas/química , Análise Espectral Raman/métodos , Fluorescência , Limite de Detecção , Estudo de Prova de Conceito , Espectrometria de Fluorescência , Vibração
12.
J Photochem Photobiol B ; 222: 112263, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34339994

RESUMO

The biosynthesis of polyphenolic compounds in cabbage waste, outer green leaves of white head cabbage (Brassica oleracea L. var. capitata subvar. alba), was stimulated by postharvest irradiation with UVB lamps or sunlight. Both treatments boosted the content of kaempferol and quercetin glycosides, especially in the basal leaf zone, as determined by the HPLC analysis of leaf extracts and by a non-destructive optical sensor. The destructive analysis of samples irradiated by the sun for 6 days at the end of October 2015 in Skierniewice (Poland) showed an increase of leaf flavonols by 82% with respect to controls. The treatment by a broadband UVB fluorescent lamp, with irradiance of 0.38 W m-2 in the 290-315 nm range (and 0.59 W m-2 in the UVA region) for 12 h per day at 17 °C along with a white light of about 20 µmol m-2 s-1, produced a flavonols increase of 58% with respect to controls. The kinetics of flavonols accumulation in response to the photochemical treatments was monitored with the FLAV non-destructive index. The initial FLAV rate under the sun was proportional to the daily radiation doses with a better correlation for the sun global irradiance (R2 = 0.973), followed by the UVA (R2 = 0.965) and UVB (R2 = 0.899) irradiance. The sunlight turned out to be more efficient than the UVB lamp in increasing the flavonols level of waste leaves, because of a significant role played by UVA and visible solar radiation in the regulation of the flavonoid accumulation in cabbage. The FLAV index increase induced on the adaxial leaf side was accompanied by a lower but still significant FLAV increase on the unirradiated abaxial side, likely due to a systemic signaling by mean of the long-distance movement of macromolecules. Our present investigation provides useful data for the optimization of postharvest photochemical protocols of cabbage waste valorization. It can represent a novel and alternative tool of vegetable waste management for the recovery of beneficial phytochemicals.


Assuntos
Brassica/efeitos da radiação , Luz , Brassica/química , Brassica/metabolismo , Clorofila/química , Cromatografia Líquida de Alta Pressão , Flavonóis/análise , Flavonóis/metabolismo , Armazenamento de Alimentos , Folhas de Planta/química , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação , Espectrometria de Fluorescência , Raios Ultravioleta
13.
ACS Sens ; 6(8): 2845-2850, 2021 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-34406746

RESUMO

Development of an easy-to-use, low-cost, household device can help the consumer quickly identify an organophosphorus (OP) residue concentration level. In this work, we demonstrate a 3D-printed, portable, fluorescent-sensing platform for smartphone-capable detection of OPs in vegetables. For development of the proposed device, we utilize the smartphone for capturing the strong thiol-activated fluorescence, which was produced by hydrolysis of OPs in the presence of alkali. The thiol-responsive AIEgen (maleimide-functionalized tetraphenylethylene) was non-emissive in both solution and the solid state but could be readily lighted up by the click addition of thiol to its MI pendant. An android application "Detection" has been developed on the basis of the gray value to analyze the different concentration levels of OPs in vegetable samples. The gray value was linearly related with the concentration of five kinds of organophosphorus residue, ranging from 0 to 20 µg/mL. It was also applied for determination of OPs residue in the leaves of cowpea, celery, and Chinese cabbage. Different from acetylcholinesterase enzyme-based sensors for poor stability under high temperature, the proposed method was a direct detection method for OPs and can be used for rapid monitoring of OPs residue concentration levels before LC-MS analysis.


Assuntos
Acetilcolinesterase , Smartphone , Corantes Fluorescentes , Impressão Tridimensional , Espectrometria de Fluorescência
14.
Molecules ; 26(16)2021 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-34443466

RESUMO

Bees and their products are useful bioindicators of anthropogenic activities and could overcome the deficiencies of air quality networks. Among the environmental contaminants, mercury (Hg) is a toxic metal that can accumulate in living organisms. The first aim of this study was to develop a simple analytical method to determine Hg in small mass samples of bees and beehive products by cold vapor atomic fluorescence spectrometry. The proposed method was optimized for about 0.02 g bee, pollen, propolis, and royal jelly, 0.05 g beeswax and honey, or 0.1 g honeydew with 0.5 mL HCl, 0.2 mL HNO3, and 0.1 mL H2O2 in a water bath (95 °C, 30 min); samples were made up to a final volume of 5 mL deionized water. The method limits sample manipulation and the reagent mixture volume used. Detection limits were lower than 3 µg kg-1 for a sample mass of 0.02 g, and recoveries and precision were within 20% of the expected value and less than 10%, respectively, for many matrices. The second aim of the present study was to evaluate the proposed method's performances on real samples collected in six areas of the Lazio region in Italy.


Assuntos
Abelhas/química , Monitoramento Biológico/métodos , Mercúrio/análise , Espectrometria de Fluorescência/métodos , Animais , Temperatura Baixa , Cucumis melo/química , Confiabilidade dos Dados , Poluição Ambiental/análise , Ácidos Graxos/análise , Mel/análise , Itália , Pólen/química , Própole/análise , Espectrofotometria Atômica/métodos , Ceras/análise
15.
ACS Appl Mater Interfaces ; 13(33): 38931-38946, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34374513

RESUMO

With the continuous development of DNA nanotechnology, various spatial DNA structures and assembly techniques emerge. Hybridization chain reaction (HCR) is a typical example with exciting features and bright prospects in biosensing, which has been intensively investigated in the past decade. In this Spotlight on Applications, we summarize the assembly principles of conventional HCR and some novel forms of linear/nonlinear HCR. With advantages like great assembly kinetics, facile operation, and an enzyme-free and isothermal reaction, these strategies can be integrated with most mainstream reporters (e.g., fluorescence, electrochemistry, and colorimetry) for the ultrasensitive detection of abundant targets. Particularly, we select several representative studies to better illustrate the novel ideas and performances of HCR strategies. Theoretical and practical utilities are confirmed for a range of biosensing applications. In the end, a deep discussion is provided about the challenges and future tasks of this field.


Assuntos
DNA/química , Técnicas Biossensoriais , Colorimetria , Técnicas Eletroquímicas , Humanos , Nanopartículas/química , Técnicas de Amplificação de Ácido Nucleico/métodos , Conformação de Ácido Nucleico , Hibridização de Ácido Nucleico/métodos , Sensibilidade e Especificidade , Espectrometria de Fluorescência
16.
Top Curr Chem (Cham) ; 379(5): 33, 2021 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-34346011

RESUMO

Organophosphorus (OP) compounds are typically a broad class of compounds that possess various uses such as insecticides, pesticides, etc. One of the most evil utilizations of these compounds is as chemical warfare agents, which pose a greater threat than biological weapons because of their ease of access. OP compounds are highly toxic compounds that cause irreversible inhibition of enzyme acetylcholinesterase, which is essential for hydrolysis of neurotransmitter acetylcholine, leading to series of neurological disorders and even death. Due to the extensive use of these organophosphorus compounds in agriculture, there is an increase in the environmental burden of these toxic chemicals, with severe environmental consequences. Hence, the rapid and sensitive, selective, real-time detection of OP compounds is very much required in terms of environmental protection, health, and survival. Several techniques have been developed over a few decades to easily detect them, but still, numerous challenges and problems remain to be solved. Major advancement has been observed in the development of sensors using the spectroscopic technique over recent years because of the advantages offered over other techniques, which we focus on in the presented review.


Assuntos
Agentes Neurotóxicos/química , Compostos Organofosforados/química , Praguicidas/química , Acetilcolinesterase/química , Acetilcolinesterase/metabolismo , Carbocianinas/química , Transporte de Elétrons , Corantes Fluorescentes/química , Humanos , Microscopia de Fluorescência , Agentes Neurotóxicos/metabolismo , Compostos Organofosforados/metabolismo , Praguicidas/metabolismo , Espectrometria de Fluorescência
17.
Nat Commun ; 12(1): 4654, 2021 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-34341342

RESUMO

Ligand-oligonucleotide transduction provides the critical pathway to integrate non-nucleic acid molecules into nucleic acid circuits and nanomachines for a variety of strand-displacement related applications. Herein, a general platform is constructed to convert the signals of ligands into desired oligonucleotides through a precise kinetic control. In this design, the ligand-aptamer binding sequence with an engineered duplex stem is introduced between the toehold and displacement domains of the invading strand to regulate the strand-displacement reaction. Employing this platform, we achieve efficient transduction of both small molecules and proteins orthogonally, and more importantly, establish logical and cascading operations between different ligands for versatile transduction. Besides, this platform is capable of being directly coupled with the signal amplification systems to further enhance the transduction performance. This kinetically controlled platform presents unique features with designing simplicity and flexibility, expandable complexity and system compatibility, which may pave a broad road towards nucleic acid-based developments of sophisticated transduction networks.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas de Amplificação de Ácido Nucleico/métodos , Conformação de Ácido Nucleico , Oligonucleotídeos/química , Aptâmeros de Nucleotídeos/genética , Aptâmeros de Nucleotídeos/metabolismo , Cinética , Ligantes , Modelos Genéticos , Modelos Moleculares , Oligonucleotídeos/genética , Oligonucleotídeos/metabolismo , Transdução de Sinais/genética , Espectrometria de Fluorescência/métodos
18.
Talanta ; 234: 122612, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34364422

RESUMO

In this work, a ratiometric fluorometric method based on luminol-Europium complex (luminol-Eu) was constructed for the detection of tetracycline (TC). Luminol-Eu, synthesized by self-assembly reaction, displayed a strongly emission peak at 453 nm under excitation at 360 nm which was derived from the aggregation-induced emission (AIE) of the luminol-Eu. In the present of TC, the fluorescence of luminol-Eu at 453 nm was quenched based on inner filter effect (IFE). Meantime, the characteristic emission peak of Eu3+ at 626 nm can be observed thank to antenna effect (AE). Therefore, we proposed a ratiometric fluorometric method for detection of TC, which allowed detection of TC from 0.5 to 80 µM with the detection limit of 39 nM. In addition, the luminol-Eu-based test paper was prepared for visual semi-quantitative detection of TC in real samples based on the color of luminol-Eu change from blue to red under 365 nm ultraviolet light. All of those results indicated that the ratiometric fluorometric strategy was fast, sensitive, and visual for detection of TC.


Assuntos
Corantes Fluorescentes , Luminol , Humanos , Limite de Detecção , Espectrometria de Fluorescência , Tetraciclina
19.
Talanta ; 234: 122615, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34364424

RESUMO

Cyanide detection methods are urgently needed due to the highly lethal to human beings. Herein, we report two fluorescence probes (Probe 1 and Probe 2) based on cyanoethylene group for cyanide anion (CN-) detection. The selective recognition for CN- was confirmed by the completely opposite green fluorescence of Probe 1 and red fluorescence of Probe 2 observed by fluorescence spectra and naked eyes. The probes take advantages of the large Stokes shift (~160 nm), rapid response (30 s), anti-interference performance and low detection limit (Probe 1: 12.4 nM, Probe 2: 101 nM). The sensing mechanism is certificated to the nucleophilic attack of CN- to electron-deficient cyanoethylene group of probes, which was demonstrated by 1H NMR titration, HR-MS, Job's plot and IR spectroscopy. Density functional theory (DFT) calculations were carried out to analyze the mechanism in theory. Further, practical applications were studied. Easy-to-use test strips treated with Probe 1 or Probe 2 are capable of CN- detection in pure drinking water. The good biocompatibility and membrane penetrability have achieved the bioimaging capability of Probe 1 and Probe 2 in living HepG-2 cells, making the probes promising for use in real lives.


Assuntos
Acrilonitrila , Água Potável , Cianetos , Corantes Fluorescentes , Humanos , Espectroscopia de Ressonância Magnética , Espectrometria de Fluorescência
20.
Talanta ; 234: 122646, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34364455

RESUMO

In this work, a novel strategy was addressed to fabricate new sensing probe (N-CDs@NaFZ) from nitrogen doped carbon dots (N-CDs) confined in Al-free ferrisilicates zeolite (NaFZ) by hydrothermal/solvothermal method. The probe was systematically characterized by HR-TEM, FTIR, energy dispersive X-ray (EDX), powder X-ray diffraction, and UV-Vis absorption and fluorescence spectrophotometers. Characterization of the designed nanocomposite template N-CDs@NaFZ by fluorescence spectrum demonstrates a variety of important conducts as stability improvements, reasonable dispersibility in water, highly emission intensity enhancement at 435 nm when excited at 340 nm, excitation independent fluorescence behaviors, great quantum yield percentage of 91.2%, and narrow size distribution 12 nm, as a nano-space confinement effect of zeolite effectively increase the rigidity of N-CDs. Based on the fluorescence quenching mechanism, the designed approach exhibits an excellent selectivity and good sensitive response to the presence of Hg(II) ions under ambient temperature, with a wide linear range of 0.1-1500 nM and lower detection limits of 5.5 pM. Influences of variables pH and incubation time were optimized. The N-CDs@NaFZ sensor was effectively applied for the detection of Hg(II) ions in the farmed and wild rainbow trout fishes, and the results are in reasonable agreement when compared with that obtained by the cold vapor atomic absorption method.


Assuntos
Mercúrio , Pontos Quânticos , Zeolitas , Animais , Carbono , Peixes , Corantes Fluorescentes , Nitrogênio , Espectrometria de Fluorescência
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