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1.
J Am Chem Soc ; 142(5): 2129-2133, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31955575

RESUMO

Labile heme (LH) is an important signaling molecule in virtually all organisms. However, specifically detecting LH remains an outstanding challenge. Herein, by learning from the bioactivation mechanism of artemisinin, we have developed the first LH-responsive small-molecule fluorescent probe, HNG, based on a 4-amino-1,8-naphthalimide (NG) fluorophore. HNG showed high selectivity for LH without interference from hemin, protein-interacting heme, and zinc protoporphyrin. Using HNG, the changes of LH levels in live cells were imaged, and a positive correlation of LH level with the degree of hemolysis was uncovered in hemolytic mice. Our study not only presents the first molecular probe for specific LH detection but also provides a strategy to construct probes with high specificity through a bioinspired approach.

2.
Chemosphere ; 237: 124517, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31549644

RESUMO

The dye wastewater treatment by membrane separation technology has obtained extensive attention in recent years. Nevertheless, it was rare for research on the removal of differently charged mixed dyes. In this study, several UiO-66-NH2 composite membranes were prepared and optimization experiments were conducted. The performance of composite membranes were evaluated by the removal of cationic (Methylene blue, MB), neutral (Rhodamine B, RB), and anionic (Congo red, CR) dyes. The optimization results demonstrated that the UiO-66-NH2/graphene oxide (UNG) composite membrane (PUF/PDA/UNG) which was loaded on polyurethane foam modified with polydopamine (PUF/PDA) had the best properties. In filtration experiments, the solution pH exhibited greater effect on the removal efficiency of MB and CR than RB. When NaCl, KCl, CaCl2 and Na2SO4 coexisted in the dye solution, the removal efficiency of MB by PUF/PDA/UNG membrane were 96.62%, 98.17%, 86.39% and 99.34% respectively. The presence of humic acid showed slight inhibitory effect on the removal of MB by PUF/PDA/UNG membrane (71.93%). The experimental results for mixed dyes filtration showed that PUF/PDA/UNG membrane could effectively remove MB, RB and CR in binary (i.e., MB/RB and RB/CR) and ternary (i.e., MB/RB/CR) systems through secondary filtration. And PUF/PDA/UNG membrane could remove MB and CR simultaneously through one-time filtration in MB/CR binary system. The removal mechanism was mainly attributed to the aggregation of mixed dyes, electrostatic interaction between dye molecules and the membrane surface, and hydrogen bonding. All results suggested that the as-prepared PUF/PDA/UNG membrane have great potential in practical treatment of dye wastewater.


Assuntos
Corantes/química , Grafite/química , Eliminação de Resíduos Líquidos , Poluentes Químicos da Água/química , Adsorção , Filtração , Indóis , Membranas , Azul de Metileno , Polímeros , Poliuretanos , Rodaminas , Águas Residuárias
3.
Chem Sci ; 10(1): 320-325, 2019 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-30713640

RESUMO

Carbon monoxide (CO) acts as an important gasotransmitter in delivering intramolecular and intermolecular signals to regulate a variety of physiological processes. This lipid-soluble gas can freely pass through the cell membrane and then diffuse to adjacent cells acting as a messenger. Although many fluorescent probes have been reported to detect intracellular CO, it is still a challenge to visualize the release behavior of endogenous CO. The main obstacle is the lack of a probe that can anchor onto the cell membrane while having the ability to image CO in real time. In this work, by grafting a polar head onto a long and linear hydrophobic Nile Red molecule, a cell membrane-anchored fluorophore ANR was developed. This design strategy of a cell membrane-anchored probe is simpler than the traditional one of using a long hydrophobic alkyl chain as a membrane-anchoring group, and endows the probe with better water solubility. ANR could rapidly bind to the cell membrane (within 1 min) and displayed a long retention time. ANR was then converted to a CO-responsive fluorescent probe (ANRP) by complexation with palladium based on a metal palladium-catalyzed reaction. ANRP exhibited a fast response to CO with a 25-fold fluorescence enhancement in vitro. The detection limit was calculated to be 0.23 µM, indicating that ANRP is sensitive enough to image endogenous CO. Notably, ANRP showed excellent cell membrane-anchoring ability. With ANRP, the release of CO from HepG2 cells under LPS- and heme-stimulated conditions was visualized and the cell self-protection effect during a drug-induced hepatotoxicity process was also studied. Moreover, ANRP was successfully applied to the detection of intracellular CO in several cell lines and tissues, and the results demonstrated that the liver is the main organ for CO production, and that cancer cells release more CO from their cells than normal cells. ANRP is the first membrane-anchored CO fluorescent probe that has the ability to reveal the relationship between CO release and diseases. It also has prospects for the studying of intercellular signaling functions of CO.

4.
Anal Chem ; 91(4): 2727-2733, 2019 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-30663316

RESUMO

Nanoscale metal-organic frameworks (NMOFs) have been applied for biomedical sensing in recent years. However, it is still a great challenge to construct a highly efficient NMOFs fluorescent probe for sensing in a biological system, with high signal-to-noise ratio, photostability, and deep tissue penetration. Herein, for the first time, we report the two-photon metal-organic framework (TP-MOF) as a sensing platform. The design of TP-MOF is based on NMOFs incorporating a target-responsive two-photon organic moiety through click chemistry. PCN-58, as a model building block, was covalently modified with a small-molecule probe for H2S or Zn2+ as model analytes. TP-MOF probes retain the fluorescence-responsive properties of the TP organic moiety and possess excellent photostability and selectivity, as well as biocompatibility. Benefiting from the near-infrared (∼820 nm) excited two-photon fluorophore, TP-MOF probes serve to sense and image their respective targets in live cells and tissue slices with a penetration of 130 µm. The molecular design presented here bodes well for the extension to other MOFs displaying sensing components for other analytes of interest.

5.
Anal Chem ; 90(19): 11680-11687, 2018 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-30191711

RESUMO

Furin, a kind of trans-Golgi proprotein convertases, plays important role in various physiological processes. It is overexpressed in many cancers and relates to tumor growth and migration. In situ detection and imaging of furin is of great significance for obtaining real-time information about its activity. However, the previously reported fluorescent probes for furin usually failed to realize in situ detection and long-term bioimaging, because these probes are based on water-soluble fluorophores, which tend to diffuse away from the reaction sites after converted by furin. Such a problem can be addressed by designing a probe, which releases a precipitating fluorophore upon furin conversion. Herein, we developed a probe HPQF for in situ detection of endogenous furin activity and long-term bioimaging by integrating a strictly insoluble solid-state fluorophore 6-chloro-2-(2-hydroxyphenyl) quinazolin-4(3H)-one (Cl-HPQ) with a furin specific peptide substrate (RVRR) through a self-immolative linker. The HPQF probe shows high selectivity and sensitivity to furin. Upon converted by furin, HPQF releases free Cl-HPQ, which precipitates near the enzyme active site. The precipitates emit bright solid-state fluorescence for in situ imaging. HPQF could truly visualize the location of intracellular furin, which was further confirmed by colocalization and immunofluorescence experiments. Excitingly, the long-term bioimaging was also achieved benefiting from its outstanding signal-stability and antidiffusion ability. HPQF was further utilized to monitor the level change of furin under stabilizing of hypoxia-inducible factor (HIF) regulated by cobalt chloride (CoCl2) as well as visualization of furin in MDA-MB-468 cell tumor tissues.


Assuntos
Corantes Fluorescentes/química , Furina/metabolismo , Microscopia de Fluorescência , Linhagem Celular Tumoral , Cobalto/química , Complexo de Golgi/metabolismo , Humanos , Fator 1 Induzível por Hipóxia/metabolismo , Peptídeos/química , Peptídeos/metabolismo
6.
J Colloid Interface Sci ; 527: 267-279, 2018 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-29800876

RESUMO

Treating dye wastewater by membrane filtration technology has received much attention from researchers all over the world, however, current studies mainly focused on the removal of singly charged dyes but actual wastewater usually contains dyes with different charges. In this study, the removal of neutral, cationic and anionic dyes in binary or ternary systems was conducted by using zirconium-based metal organic frameworks loaded on polyurethane foam (Zr-MOFs-PUF) membrane. The Zr-MOFs-PUF membrane was fabricated by an in-situ hydrothermal synthesis approach and a hot-pressing process. Neutrally charged Rhodamine B (RB), positively charged Methylene blue (MB), and negatively charged Congo red (CR) were chosen as model pollutants for investigating filtration performance of the membrane. The results of filtration experiments showed that the Zr-MOFs-PUF membrane could simultaneously remove RB, MB, and CR not only from their binary system including RB/MB, RB/CR, and MB/CR mixtures, but also from RB/MB/CR ternary system. The removal of dyes by Zr-MOFs-PUF membrane was mainly attributed to the electrostatic interactions, hydrogen bond interaction, and Lewis acid-base interactions between the membrane and dye molecules. The maximum removal efficiencies by Zr-MOFs-PUF membrane were 98.80% for RB at pH ≈ 7, 97.57% for MB at pH ≈ 9, and 87.39% for CR at pH ≈ 3. Additionally, when the NaCl concentration reached 0.5 mol/L in single dye solutions, the removal efficiencies of RB, MB, and CR by Zr-MOFs-PUF membrane were 93.08%, 79.52%, and 97.82%, respectively. All the results suggested that the as-prepared Zr-MOFs-PUF membrane has great potential in practical treatment of dye wastewater.

7.
Chemosphere ; 204: 378-389, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29674150

RESUMO

Here we demonstrated an alternative partial reduction graphene oxide/metal-organic frameworks nano-scale laminated membrane for dyes and heavy metal ions removal at low pressure. Compared with pure prGO membranes, the novel UiO-66-(COOH)2/prGO membranes with loose structure and excellent selective permeability demonstrated significant enhancements of permeation for low-pressure nanofiltration. The UiO-66-(COOH)2/prGO membranes possess more nanochannels structure, high surface charge and stability, which were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). The experiment result indicated that the flux of composite membranes for pure water was 20.0 ±â€¯2.5 Lm-2h-1bar-1, about 2.9 times higher than that (6.5 ±â€¯1.2 Lm-2h-1bar-1) of the pristine prGO membranes at the same prGO loading. The high rejection of UiO-66-(COOH)2/prGO membranes for organic dyes (98.2 ±â€¯1.7% for negatively charged congo red and 92.55 ±â€¯2.5% for positively charged methylene blue) were exhibited. Moreover, the rejection for heavy metal ions also can be efficiently improved up to 96.5-83.1% for Cu2+ and 92.6-80.4% for Cd2+, indicating the positive effect of the electrostatic interaction on the nanochannels for ions. Therefore, it is reasonable to believe that novel UiO-66-(COOH)2/prGO membranes have great potential application in water treatment.


Assuntos
Filtração/métodos , Grafite/química , Estruturas Metalorgânicas/química , Nanopartículas/química , Nanotecnologia/métodos , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Pressão , Poluentes Químicos da Água/química
8.
Anal Chem ; 90(5): 3118-3123, 2018 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-29409318

RESUMO

RNA-cleaving DNAzymes have been demonstrated as a promising platform for sensing metal ions. However, the poor biological imaging performance of RNA-cleaving DNAzyme-based fluorescent probes has limited their intracellular applications. Compared with traditional one-photon fluorescence imaging, two-photon (TP) fluorescent probes have shown advantages such as increased penetration depth, lower tissue autofluorescence, and reduced photodamage. Herein, for the first time, we developed an RNA-cleaving DNAzyme-based TP imaging probe (TP-8-17ES-AuNP) for Zn2+ detection in living cells by modifying a Zn2+-specific DNAzyme (8-17) with a TP fluorophore (TP-8-17ES) and using gold nanoparticles (AuNPs) for intracellular delivery. The modified TP-8-17ES exhibits good two-photon properties and excellent photostability. For the TP-8-17ES-AuNP, in the absence of Zn2+, the TP fluorophore is quenched by both AuNPs and the molecular quencher. Only in the presence of Zn2+ does the DNAzyme cleave the TP fluorophore-labeled substrate strand, resulting in fluorescence enhancement and TP imaging. Such probe shows remarkable selectivity of Zn2+ over other metal ions existing in the biological environment. Benefiting from the labeled TP fluorophore, the near-infrared (NIR) excited probe has the capability of TP imaging of Zn2+ in living cells and tissue with a deep tissue penetration up to 160 µm. This method can be generally applied to detect other metal ions in biological systems under TP imaging with higher tissue penetration ability and lower phototoxicity.


Assuntos
Benzotiazóis/química , DNA Catalítico/química , Corantes Fluorescentes/química , Ouro/química , Nanopartículas Metálicas/química , Zinco/metabolismo , Animais , Benzotiazóis/síntese química , Benzotiazóis/efeitos da radiação , Benzotiazóis/toxicidade , DNA Catalítico/toxicidade , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/efeitos da radiação , Corantes Fluorescentes/toxicidade , Células HeLa , Humanos , Raios Infravermelhos , Nanopartículas Metálicas/toxicidade , Microscopia Confocal , Ratos , Zinco/química
9.
J Colloid Interface Sci ; 505: 67-78, 2017 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-28570853

RESUMO

Polyurethane foam membrane filled with humic acid-chitosan crosslinked gels (HA-CS-PUF) for dye removal was prepared by soaking the foams into humic acid-chitosan (HA-CS) crosslinked gels and hot-pressing them into membranes. Scanning electron microscope, derivative thermogravimetry and X-ray photoelectron spectroscopy were used to characterize the HA-CS-PUF membrane. Results showed that the interaction of HA and CS was mainly through ionic cross-linking between carboxyl and protonated amino groups. Three types of dyes, including positively charged methylene blue (MB), neutrally charged rhodamine B (RB) and negatively charged methyl orange (MO), were used to test membranes properties through static adsorption and membrane filtration experiments. It revealed that adsorption process was better fitted with Pseudo-second-order and Freundlich model. In membrane filtration experiments, we found that the retention rates of membrane 1 (ratio of HA to CS was 0:1) to MO and RB were 99.7% and 65%, respectively, and nearly no retention to MB. While membrane 4 (ratio of HA to CS was 0.2:1) can retain 97.7% of MO, 71.6% of RB and 62.1% of MB. Based on the experimental results, membrane 1 possessed the ability of selectively separating MB from MO/MB and RB/MB solutions, and membrane 4 can simultaneously retain RB and MB from RB/MB solution.

10.
Anal Chem ; 89(14): 7641-7648, 2017 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-28613839

RESUMO

Endoplasmic reticulum aminopeptidase 1 (ERAP1), a metallopeptidase belonging to the M1 peptidase family, plays an important role in antigen processing in vivo. Additionally, many diseases are caused by ERAP1 perturbation. Thus, an efficient method for monitoring its content is extremely important for disease diagnosis and treatment. However, few fluorescent probes have been reported for efficiently monitoring ERAP1 in living cells and tissues. In this work, a two-photon fluorescent probe (SNCL) containing 1,8-naphthalimide (two-photon fluorophore), l-leucine (trigger moiety), and a methyl sulfonamide moiety (endoplasmic reticulum-targeting group) for imaging ERAP1 activity in living cells is reported for the first time. The optimized probe exhibited high sensitivity toward ERAP1, with about a 95-fold fluorescence enhancement at 550 nm. Herein, we monitored ERAP1 with SNCL by introducing interferon-γ to induce ERAP1 activity in living cells. The content of ERAP1 was dependent on the redox state of the endoplasmic reticulum, which was demonstrated by using SNCL to monitor the enzymatic activity of ERAP1 under different redox conditions. Excitingly, SNCL was also successfully applied for monitoring ERAP1 in tumor tissue with an imaging depth of 50-120 µm. In conclusion, SNCL not only can be used for the sensitive detection of endogenous ERAP1 in living cells and tumor tissues but also can serve as a potentially useful tool to reveal ERAP1-related diseases.


Assuntos
Aminopeptidases/análise , Retículo Endoplasmático/enzimologia , Corantes Fluorescentes/química , Antígenos de Histocompatibilidade Menor/análise , Fótons , Aminopeptidases/metabolismo , Animais , Corantes Fluorescentes/síntese química , Células HeLa , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Microscopia de Fluorescência , Antígenos de Histocompatibilidade Menor/metabolismo , Estrutura Molecular , Imagem Óptica , Oxirredução
11.
Chemosphere ; 184: 347-357, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28605705

RESUMO

Nanotechnology has great potential in water purification. However, the limitations such as aggregation and toxicity of nanomaterials have blocked their practical application. In this work, a novel copper nanoparticles-decorated graphene sponge (Cu-GS) was synthesized using a facile hydrothermal method. Cu-GS consisting of three-dimensional (3D) porous graphene network and well-dispersed Cu nanoparticles exhibited high antibacterial efficiency against Esherichia coli when used as a bactericidal filter. The morphological changes determined by scanning electron microscope and fluorescence images measured by flow cytometry confirmed the involvement of membrane damage induced by Cu-GS in their antibacterial process. The oxidative ability of Cu-GS and intercellular reactive oxygen species (ROS) were also determined to elucidate the possible antibacterial mechanism of Cu-GS. Moreover, the concentration of released copper ions from Cu-GS was far below the drinking water standard, and the copper ions also have an effect on the antibacterial activity of Cu-GS. Results suggested that Cu-GS as a novel bactericidal filter possessed a potential application of water disinfection.


Assuntos
Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Grafite/química , Nanopartículas Metálicas/química , Purificação da Água/métodos , Cobre/química , Desinfecção , Nanotecnologia/métodos
12.
J Colloid Interface Sci ; 498: 229-238, 2017 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-28340423

RESUMO

Carbon nanotubes (CNTs), usually with a superior affinity with organic chemicals, are expected to ultimately released to the environment through their manufacturing, usage, and eventual disposal, which will influence the mobility and environmental risk of nonsteroidal anti-inflammatory drugs (NSAIDs). In this study, batch and column experiments were performed to examine the effects of two kinds of multi-walled carbon nanotubes (MWCNTs: MWCNT2040, MWCNT0815) and one kind of single-walled carbon nanotubes (SWCNTs) on the environmental fate of two NSAIDs, paracetamol (PA) and diclofenac sodium (DS), in sediments. Impact ways of CNTs including addition in inflow and mixing with sediments were investigated. The adsorption capacity of NSAIDs on sediments increased with increasing CNTs/sediments ratios and in an order of MWCNT2040

Assuntos
Anti-Inflamatórios não Esteroides/química , Poluentes Ambientais/química , Sedimentos Geológicos/química , Nanotubos de Carbono/química , Adsorção , Impedância Elétrica , Concentração de Íons de Hidrogênio , Tamanho da Partícula , Porosidade , Termodinâmica
13.
Talanta ; 164: 662-667, 2017 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-28107987

RESUMO

In this paper, based on reciprocal chiral substrate specificity, taking achiral molecules, ethanolamine (EA) and malachite green (MG) as two model targets, biostable L- DNA aptamers and L-RNA aptamers were generated respectively by chiral inversion of existing D-aptamers. In the detection of EA with L-DNA aptamer-based sensors, the feasibility of our strategy was confirmed, while in the detection of MG with L-RNA aptamers, linear calibration curves were obtained in the range from 0.1 to 5µm with the detection limit of 0.065µm under optimized experimental conditions. The results demonstrated that the mirror-image L-aptamers have identical recognition capability as D-aptamers. Meanwhile, L-aptamers have superior biostability to resist nuclease digestion, protein binding interference and off-target effects, enabling their applications in complex practical samples, such as lake water and fish tissue extractions. Our work provides a simple, yet universal and efficient way to develop biostable aptamers.


Assuntos
Aptâmeros de Nucleotídeos/química , Estabilidade de Medicamentos , Etanolamina/química , Corantes de Rosanilina/química , Estereoisomerismo , Especificidade por Substrato
14.
Anal Sci ; 32(9): 951-6, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27682399

RESUMO

The present article reports a novel biosensor for organophosphorus pesticides based on fluorescence resonance energy transfer (FRET) between nitrogen-doped carbon dots (NC-dots) and gold nanoparticles (AuNPs). The effective NC-dots/AuNPs assembly through the Au-N interaction results in good fluorescence quenching. Active acetylcholinesterase (AChE) catalyzes the hydrolysis of acetylthiocholine into -SH containing thiocholine to replace the NC-dots and trigger the aggregation of AuNPs. In the presence of paraoxon, the activity of AChE is inhibited, and thus preventing the generation of thiocholine, causing fewer NC-dots to be replaced. As a consequence, the fluorescence intensity gradually decreases with increasing amount of paraoxon. This biosensor does not require any complex synthesis or modification, and the results show a wide detection range of from 10(-4) to 10(-9) g/L with a detection limit of 1.0 × 10(-9) g/L (3.6 × 10(-12) mol/L). Two linear response regions have been reported with a turning point at about 10(-6) g/L and three different factors that would influence the response behavior. These phenomena discussed in detail so as to explain the special response mechanism.


Assuntos
Carbono/química , Transferência Ressonante de Energia de Fluorescência/métodos , Ouro/química , Nanopartículas Metálicas/química , Nitrogênio/química , Compostos Organofosforados/análise , Pontos Quânticos/química , Técnicas Biossensoriais , Sucos de Frutas e Vegetais/análise , Limite de Detecção , Malus/química , Compostos Organofosforados/química , Praguicidas/análise , Praguicidas/química
15.
J Colloid Interface Sci ; 471: 94-102, 2016 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-26994349

RESUMO

Silver nanoparticle-decorated magnetic graphene oxide (MGO-Ag) was synthesized by doping silver and Fe3O4 nanoparticles on the surface of GO, which was used as an antibacterial agent. MGO-Ag was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Energy dispersive X-ray (EDS), X-ray diffraction (XRD), Raman spectroscopy and magnetic property tests. It can be found that magnetic iron oxide nanoparticles and nano-Ag was well dispersed on graphene oxide; and MGO-Ag exhibited excellent antibacterial activity against Escherichia coli and Staphylococcus aureus. Several factors were investigated to study the antibacterial effect of MGO-Ag, such as temperature, time, pH and bacterial concentration. We also found that MGO-Ag maintained high inactivation rates after use six times and can be separated easily after antibacterial process. Moreover, the antibacterial mechanism is discussed and the synergistic effect of GO, Fe3O4 nanoparticles and nano-Ag accounted for high inactivation of MGO-Ag.


Assuntos
Antibacterianos , Escherichia coli/crescimento & desenvolvimento , Grafite/química , Nanopartículas Metálicas/química , Prata/química , Staphylococcus aureus/crescimento & desenvolvimento , Antibacterianos/síntese química , Antibacterianos/química , Antibacterianos/farmacologia , Nanopartículas Metálicas/ultraestrutura
16.
Chem Commun (Camb) ; 51(60): 12095-8, 2015 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-26120805

RESUMO

By employing DNAzyme as a recognition group and amplifier, and DNA-stabilized silver nanoclusters (DNA/AgNCs) as signal reporters, we reported for the first time a label-free catalytic and molecular beacon as an amplified biosensing platform for highly selective detection of cofactors such as Pb(2+) and L-histidine.


Assuntos
Técnicas Biossensoriais/métodos , DNA Catalítico/metabolismo , DNA/metabolismo , Histidina/análise , Chumbo/análise , Nanoestruturas/química , Prata/química , Cátions Bivalentes/análise , Cátions Bivalentes/metabolismo , DNA/química , Histidina/metabolismo , Chumbo/metabolismo , Limite de Detecção , Rios/química , Espectrometria de Fluorescência/métodos
17.
Chem Commun (Camb) ; 51(6): 979-95, 2015 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-25336076

RESUMO

DNAzymes, screened through in vitro selection, have shown great promise as molecular tools in the design of biosensors and nanodevices. The catalytic activities of DNAzymes depend specifically on cofactors and show multiple enzymatic turnover properties, which make DNAzymes both versatile recognition elements and outstanding signal amplifiers. Combining nanomaterials with unique optical, magnetic and electronic properties, DNAzymes may yield novel fluorescent, colorimetric, surface-enhanced Raman scattering (SERS), electrochemical and chemiluminescent biosensors. Moreover, some DNAzymes have been utilized as functional components to perform arithmetic operations or as "walkers" to move along DNA tracks. DNAzymes can also function as promising therapeutics, when designed to complement target mRNAs or viral RNAs, and consequently lead to down-regulation of protein expression. This feature article focuses on the most significant achievements in using DNAzymes as recognition elements and signal amplifiers for biosensors, and highlights the applications of DNAzymes in logic gates, DNA walkers and nanotherapeutics.


Assuntos
Técnicas Biossensoriais , DNA Catalítico/metabolismo , Nanotecnologia
18.
Anal Chem ; 86(10): 5009-16, 2014 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-24731194

RESUMO

Development of efficient methods for highly sensitive and rapid screening of specific oligonucleotide sequences is essential to the early diagnosis of serious diseases. In this work, an aggregated cationic perylene diimide (PDI) derivative was found to efficiently quench the fluorescence emission of a variety of anionic oligonucleotide-labeled fluorophores that emit at wavelengths from the visible to NIR region. This broad-spectrum quencher was then adopted to develop a multicolor biosensor via a label-free approach for multiplexed fluorescent detection of DNA. The aggregated perylene derivative exhibits a very high quenching efficiency on all ssDNA-labeled dyes associated with biosensor detection, having efficiency values of 98.3 ± 0.9%, 97 ± 1.1%, and 98.2 ± 0.6% for FAM, TAMRA, and Cy5, respectively. An exonuclease-assisted autocatalytic target recycling amplification was also integrated into the sensing system. High quenching efficiency combined with autocatalytic target recycling amplification afforded the biosensor with high sensitivity toward target DNA, resulting in a detection limit of 20 pM, which is about 50-fold lower than that of traditional unamplified homogeneous fluorescent assay methods. The quencher did not interfere with the catalytic activity of nuclease, and the biosensor could be manipulated in either preaddition or postaddition manner with similar sensitivity. Moreover, the proposed sensing system allows for simultaneous and multicolor analysis of several oligonucleotides in homogeneous solution, demonstrating its potential application in the rapid screening of multiple biotargets.


Assuntos
Técnicas Biossensoriais/instrumentação , DNA/química , DNA de Cadeia Simples/química , Endonucleases/química , Corantes Fluorescentes , Sequenciamento de Nucleotídeos em Larga Escala , Oligonucleotídeos/química
19.
Biosens Bioelectron ; 58: 320-5, 2014 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-24662061

RESUMO

Fluorescent sensing systems based on the quenching of fluorophores have found wide applications in bioassays. An efficient quencher will endow the sensing system a high sensitivity. The frequently used quenchers are based on organic molecules or nanomaterials, which usually need tedious synthesizing and modifying steps, and exhibit different quenching efficiencies to different fluorophores. In this work, we for the first time report that aggregated perylene derivative can serve as a broad-spectrum and label-free quencher that is able to efficiently quench a variety of fluorophores, such as green, red and far red dyes labeled on DNA. By choosing nucleases as model biomolecules, such a broad-spectrum quencher was then employed to construct a multiplexed bioassay platform through a label-free manner. Due to the high quenching efficiency of the aggregated perylene, the proposed platform could detect nuclease with high sensitivity, with a detection limit of 0.03U/mL for EcoRV, and 0.05U/mL for EcoRI. The perylene quencher does not affect the activity of nuclease, which makes it possible to design post-addition type bioassay platform. Moreover, the proposed platform allows simultaneous and multicolor analysis of nucleases in homogeneous solution, demonstrating its value of potential application in rapid screening of multiple bio-targets.


Assuntos
Bioensaio/instrumentação , Técnicas Biossensoriais/instrumentação , DNA/química , Desoxirribonuclease EcoRI/análise , Perileno/química , Espectrometria de Fluorescência/instrumentação , DNA/genética , Desoxirribonuclease EcoRI/química , Desoxirribonuclease EcoRI/genética , Desenho de Equipamento , Análise de Falha de Equipamento , Coloração e Rotulagem
20.
Anal Chem ; 85(16): 7875-81, 2013 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-23865565

RESUMO

H2S is the third endogenously generated gaseous signaling compound and has also been known to involve a variety of physiological processes. To better understand its physiological and pathological functions, efficient methods for monitoring of H2S in living systems are desired. Although quite a few one photon fluorescence probes have been reported for H2S, two-photon (TP) probes are more favorable for intracellular imaging. In this work, by employing a donor-π-acceptor-structured naphthalene derivative as the two-photon fluorophore and an azide group as the recognition unit, we reported a new two-photon bioimaging probe 6-(benzo[d]thiazol-2'-yl)-2-azidonaphthalene (NHS1) for H2S with improved sensitivity. The probe shows very low background fluorescence in the absence of H2S. In the presence of H2S, however, a significant enhancement for both one photon and TP excited fluorescence were observed, resulting in a high sensitivity to H2S in aqueous solutions with a detection limit of 20 nM observed, much lower than the previously reported TP probe. The probe also exhibits a wide linear response concentration range (0-5 µM) to H2S with high selectivity. All these features are favorable for direct monitoring of H2S in complex biological samples. It was then applied for direct TP imaging of H2S in living cells with satisfactory sensitivity, demonstrating its value of practical application in biological systems.


Assuntos
Corantes Fluorescentes/química , Sulfeto de Hidrogênio/análise , Naftalenos/química , Células HeLa , Humanos , Limite de Detecção , Espectroscopia de Ressonância Magnética , Microscopia de Fluorescência , Fótons , Espectrofotometria Ultravioleta
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