Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 39
Filtrar
Mais filtros

País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Analyst ; 145(24): 7858-7863, 2021 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-33020770

RESUMO

The abnormal variation of the mucin 1 (MUC1) protein level is associated with the development of multiple cancers, and the monitoring of trace MUC1 can be useful for early disease diagnosis. Here, on the basis of the synchronization of DNA-fueled sequence recycling and dual rolling circle amplification (RCA), the establishment of a non-label and highly sensitive fluorescent aptamer-based detection strategy for the MUC1 protein biomarker is described. The target MUC1 binds the aptamer hairpin probe and causes its structure switching to release an ssDNA tail to trigger the recycling of the complex via two toehold-mediated strand displacement reactions under assistance of a fuel DNA. Such a recycling amplification leads to the formation of a partial dsDNA duplex with two primers at both ends, which cooperatively bind the circular DNA ring template to start the dual RCA to produce many G-quadruplex sequences. The protoporphyrin IX dye further associates with the G-quadruplex structures to show a dramatically elevated fluorescent signal for sensitively detecting MUC1 with a low detection limit of 0.5 pM. The established aptamer-based detecting strategy is also highly selective and can realize assay of MUC1 in diluted human serums, highlighting its potential for the detection of different protein biomarkers at low contents.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Quadruplex G , Biomarcadores , DNA , Primers do DNA , Humanos , Limite de Detecção , Técnicas de Amplificação de Ácido Nucleico
2.
Nano Lett ; 20(12): 8890-8896, 2020 12 09.
Artigo em Inglês | MEDLINE | ID: mdl-33164530

RESUMO

Fluorescence microscopy has been one of the most discovery-rich methods in biology. In the digital age, the discipline is becoming increasingly quantitative. Virtually all biological laboratories have access to fluorescence microscopes, but abilities to quantify biomolecule copy numbers are limited by the complexity and sophistication associated with current quantification methods. Here, we present DNA-origami-based fluorescence brightness standards for counting 5-300 copies of proteins in bacterial and mammalian cells, tagged with fluorescent proteins or membrane-permeable organic dyes. Compared to conventional quantification techniques, our brightness standards are robust, straightforward to use, and compatible with nearly all fluorescence imaging applications, thereby providing a practical and versatile tool to quantify biomolecules via fluorescence microscopy.


Assuntos
DNA , Corantes Fluorescentes , Animais , Microscopia de Fluorescência , Proteínas
3.
Analyst ; 145(2): 434-439, 2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-31793560

RESUMO

Detection of aberrant ATP concentrations with high sensitivity and selectivity is of critical importance for monitoring many biological processes and disease stages. By coupling extension/excision amplification with target recycling, we have established an aptamer-based method for label-free fluorescence ATP detection in human serum with high sensitivity. The ATP target molecules associate with the aptamer-containing double hairpin probes and cause conformational changes of the probes to initiate the cyclic strand extension/excision processes in the presence of polymerase, endonuclease and assistance sequences for the recycling of ATP and the production of a large number of G-quadruplex sequences. The organic dye thioflavin T subsequently binds these G-quadruplex sequences to yield substantially enhanced fluorescence emission for achieving highly sensitive detection of ATP down to 2.2 nM in the range of 5 to 200 nM without using any labels. The developed aptamer sensing method also exhibits high selectivity and allows the monitoring of ATP at low concentrations in diluted real samples, which offers promising opportunities to establish effective signal magnification means for the detection of various biomolecules at trace levels.


Assuntos
Trifosfato de Adenosina/sangue , Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , DNA/química , Trifosfato de Adenosina/química , Sequência de Bases , Benzotiazóis/química , Corantes Fluorescentes/química , Quadruplex G , Humanos , Sequências Repetidas Invertidas , Limite de Detecção , Espectrometria de Fluorescência
4.
Anal Chem ; 91(5): 3628-3635, 2019 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-30735035

RESUMO

Self-assembled functional DNA structures have proven to be excellent materials for designing and implementing a variety of nanoscale devices. We demonstrate here that a rationally designed and programmable DNA ring/hairpin-constrained structure can achieve in situ ligation-free rolling circle amplification (RCA), which further leads to highly specific, sensitive, and multicolor imaging of mRNA molecules in single cells. Such a structure aims at addressing current challenges in terms of simplicity, sensitivity, and multiplexing capability related to the detection and imaging of intracellular mRNA sequences. With this new DNA ring/hairpin-RCA approach, we are able to detect the target mRNAs with high sensitivity at the subpicomolar levels in vitro. Besides, the multiplexing capability of the DNA structures can be readily realized by barcoding the DNA rings and hairpins with distinct sequences. Due to the excellent sequence recognition ability of the hairpins, the DNA structures exhibit single-base variation discrimination capability for the target mRNA and can be used to image trace amounts of down-expressed mRNAs in single cells. Moreover, drug-dependent mRNA expression variations can also be clearly differentiated by these DNA structures, highlighting the great potential of such structures for early disease diagnosis and for screening possible therapeutic drugs.


Assuntos
DNA/química , Técnicas de Amplificação de Ácido Nucleico/métodos , RNA Mensageiro/análise , Análise de Célula Única/métodos , Animais , Regulação da Expressão Gênica , Humanos , Conformação de Ácido Nucleico , Análise de Sequência de RNA
5.
Anal Chem ; 89(18): 9934-9940, 2017 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-28809475

RESUMO

The detection of specific intracellular microRNAs (miRNAs) in living cells can potentially provide insight into the causal mechanism of cancer metastasis and invasion. However, because of the characteristic nature of miRNAs in terms of small sizes, low abundance, and similarity among family members, it is a great challenge to monitor miRNAs in living cells, especially those with much lower expression levels. In this work, we describe the establishment of a DNA-fueled and catalytic molecule machinery in cell signal amplification approach for monitoring trace and under-expressed miRNAs in living cells. The presence of the target miRNA releases the hairpin sequences from the dsDNA (containing the fluorescence resonance energy transfer (FRET) pair-labeled and unfolded hairpin sequences)-conjugated gold nanoparticles (dsDNA-AuNPs), and the DNA fuel strands assist the recycling of the target miRNA sequences via two cascaded strand displacement reactions, leading to the operation of the molecular machine in a catalytic fashion and the release of many hairpin sequences. As a result, the liberated hairpin sequences restore the folded hairpin structures and bring the FRET pair into close proximity to generate significantly amplified signals for detecting trace miRNA targets. Besides, the dsDNA-AuNP nanoprobes have good nuclease stability and show low cytotoxicity to cells, and the application of such a molecular system for monitoring trace and under-expressed miRNAs in living cells has also been demonstrated. With the advantages of in cell signal amplification and reduced background noise, the developed method thus offers new opportunities for detecting various trace intracellular miRNA species.


Assuntos
DNA/química , MicroRNAs/análise , Células A549 , Catálise , Sobrevivência Celular , Transferência Ressonante de Energia de Fluorescência , Corantes Fluorescentes/química , Corantes Fluorescentes/farmacologia , Ouro/química , Ouro/farmacologia , Humanos , Células MCF-7 , Nanopartículas Metálicas/química , Microscopia Confocal , Imagem Óptica , Células Tumorais Cultivadas
6.
Anal Bioanal Chem ; 409(27): 6421-6427, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28871452

RESUMO

The determination of the level of Cu2+ plays important roles in disease diagnosis and environmental monitoring. By coupling Cu+-catalyzed click chemistry and metal ion-dependent DNAzyme cyclic amplification, we have developed a convenient and sensitive colorimetric sensing method for the detection of Cu2+ in human serums. The target Cu2+ can be reduced by ascorbate to form Cu+, which catalyzes the azide-alkyne cycloaddition between the azide- and alkyne-modified DNAs to form Mg2+-dependent DNAzymes. Subsequently, the Mg2+ ions catalyze the cleavage of the hairpin DNA substrate sequences of the DNAzymes and trigger cyclic generation of a large number of free G-quadruplex sequences, which bind hemin to form the G-quadruplex/hemin artificial peroxidase to cause significant color transition of the sensing solution for sensitive colorimetric detection of Cu2+. This method shows a dynamic range of 5 to 500 nM and a detection limit of 2 nM for Cu2+ detection. Besides, the level of Cu2+ in human serums can also be determined by using this sensing approach. With the advantages of simplicity and high sensitivity, such sensing method thus holds great potential for on-site determination of Cu2+ in different samples. Graphical abstract Sensitive colorimetric detection of copper (II) by coupling click chemistry with metal ion-dependentDNAzymes.


Assuntos
Técnicas Biossensoriais/métodos , Colorimetria/métodos , Cobre/sangue , DNA Catalítico/química , Alcinos/química , Azidas/química , Cátions Bivalentes/sangue , Química Click/métodos , Quadruplex G , Hemina/química , Humanos , Limite de Detecção
7.
Anal Chem ; 86(1): 953-8, 2014 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-24328253

RESUMO

The employment of DNAzyme probes for visual biodetections has received increasing interest recently due to the simple nature of this type of assay. However, achieving high sensitivity and detecting targets beyond nucleic acids remain two major challenges in DNAzyme-based visual detections. In this work, based on a new quadratic amplification strategy, we developed a sensitive and visual detection method for cytokines by using hairpin aptamer DNAzyme probes. The target cytokine, interferon γ (IFN-γ), associates with the aptamer sequences and unfolds the hairpin structure of the probes, leading to simultaneous recycling of the target IFN-γ (assisted by Bst-polymerase) and the DNA sequences (aided by λ exonuclease) to achieve quadratic amplification. This quadratic amplification results in the generation of numerous peroxidase-mimicking DNAzymes, which cause significantly intensified color change of the probe solution for highly sensitive detection of IFN-γ by the naked eye down to 50 pM. The proposed visual sensing method shows also high selectivity toward the target IFN-γ and can be performed in homogeneous solutions with using completely unmodified, synthetic aptamer DNAzyme probes. These distinct advantages of our developed assay protocol make it a potential platform for detecting various types of biomolecules with careful probe designs.


Assuntos
Aptâmeros de Nucleotídeos/química , Citocinas/análise , Sondas de DNA/química , DNA Catalítico/química , Marcação de Genes/métodos , Técnicas de Amplificação de Ácido Nucleico/métodos , Animais , Aptâmeros de Nucleotídeos/genética , Bovinos , Citocinas/genética , Sondas de DNA/genética , DNA Catalítico/genética
8.
Spectrochim Acta A Mol Biomol Spectrosc ; 321: 124682, 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38936209

RESUMO

The accurate and sensitive detection of metallothionein (MT) is of great significance in the fields of biomedical, toxicological and environmental sciences. In this work, based on the high affinity interaction between MT and the heavy metal ions of Hg2+ and the significant signal amplification capability of Cas12a/crRNA enzyme as well, we report a simple and highly sensitive method for visual detection of MT, a biomarker in fish for heavy metal ion-induced water bio-pollution. The target MT molecules bind Hg2+ in the Hg2+- complexed hairpin DNA probes to unfold the hairpin structure into ssDNAs, which hybridize with the partial dsDNA duplexes via strand displacement to yield specific sequence-containing dsDNAs. Cas12a/crRNA recognizes these specific sequences to activate its enzyme activity to cyclically cleave the ssDNA linkers in the blue colored gold nanoparticle aggregates to transit their color into red to realize visual detection of MT. Owing to the signal amplification by Cas12a/crRNA, as low as 25 nM of MT can be visually detected with naked eye. In addition, our colorimetric detection method has high selectivity for MT against other interference proteins and can detect MT in the livers and kidneys of crucian carps bought from a local supermarket. Moreover, the developed assay overcomes the limitations of conventional MT detection methods in terms of complexity, high cost and low sensitivity and can therefore offer new methods for monitoring water bio-pollutions.

9.
Talanta ; 278: 126455, 2024 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-38917548

RESUMO

Accurate and sensitive monitoring of the concentration change of anti-digoxigenin (Anti-Dig) antibody is of great importance for diagnosing infectious and immunological diseases. Combining a novel triplex aptamer nanoswitch and the high signal-to-noise ratio of lighting-up RNA aptamer signal amplification, a label-free and ultrasensitive fluorescent sensing approach for detecting Anti-Dig antibodies is described. The target Anti-Dig antibodies recognize and bind with the nanoswitch to open its triplex helix stem structure to release Taq DNA polymerase and short ssDNA primer simultaneously, which activates the Taq DNA polymerase to initiate downstream strand extension of ssDNA primer to yield specific dsDNA containing RNA promoter sequence. T7 RNA polymerase recognizes and binds to these promoter sequences to initiate RNA transcription reaction to produce many RNA aptamer sequences. These aptamers can recognize and bind with Malachite Green (MG) dye specifically and produce highly amplified fluorescent signal for monitoring Anti-Dig antibodies from 50 pM to 50 nM with a detection limit down to 33 pM. The method also exhibits high selectivity for Anti-Dig antibodies and can be used to discriminate trace Anti-Dig antibodies in diluted serum samples. Our method is superior to many immunization-based Anti-Dig antibody detection methods and thus holds great potential for monitoring disease progression and efficacy.

10.
ACS Appl Mater Interfaces ; 16(6): 8045-8054, 2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38316124

RESUMO

Solid-state lithium batteries are promising next-generation energy storage systems for electric vehicles due to their high energy density and high safety and require achieving and maintaining intimate solid-solid interfaces for lithium-ion and electron transport. However, the solid-solid interfaces may evolve over cycling, disrupting the ion and electron diffusion pathways and leading to rapid performance degradation. The development of solid-state lithium batteries has been hindered by the lack of fundamental understanding of the interfacial microstructure change over cycling and its relation to electrochemical properties. Herein, we prepared a quasi-solid-state lithium battery, 30%LiFePO4-55%Li1.5Al0.5Ge1.5(PO4)3-15%C| Li1.5Al0.5Ge1.5(PO4)3|Li, by spark plasma sintering, and employed it as a model system to reveal the microstructure evolution at the solid-solid interfaces with electrochemical performance of the batteries. The electrochemical assessment showed that the quasi-solid-state lithium battery exhibited a discharge specific capacity of about 150 mAh g-1 in the first 80 cycles and then experienced severe capacity attenuation afterward, accompanied by a gradual internal resistance increase. Scanning electron microscopy observation showed that more cracks were formed inside the solid-state electrolyte and at the solid-solid interfaces as the battery cycled from 10 to 67 and 157 cycles. Detailed microstructure and phase analysis by high-resolution transmission electron microscopy and selected area electron diffraction discovered that the crack formation and performance decay were mainly caused by (1) the volume change of the LiFePO4 composite cathode during cycling, (2) the grain expansion of the Li1.5Al0.5Ge1.5(PO4)3 solid-state electrolyte at its interface with lithium anode, and (3) the formation of a solid electrolyte interphase layer, comprising Li2CO3, LiF, and LiTFSI, at the cathode-solid-state electrolyte interface. These microstructure changes built up over repeated battery cycling, ultimately causing the structure collapse and battery failure. The microstructure evolution information is expected to guide the design of better structures and interfaces for solid-state lithium batteries.

11.
Anal Chim Acta ; 1289: 342187, 2024 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-38245202

RESUMO

The abnormal expression levels of miRNAs have been proven to be highly related to the generation of various diseases and are also closely associated with the stages and types of disease development. The novel RNA aptamers-based homogenous fluorescent methods were simple, with low background signal and high signal-to-noise ratio, but lacked effective signal amplification technology to achieve sensitive detection of trace miRNA markers. There is an urgent need for combining effective nucleic acid amplification technology with RNA aptamer to achieve highly sensitive and accurate detection of miRNA. For this purpose, a new DNA multi-arm nanostructure-based dual rolling circle transcription machinery for the generation of lighting-up MG RNA aptamers is constructed for label-free and highly sensitive sensing of miRNA-21. In this system, the target miRNA-21 induces a structural transformation of the DNA multi-arm nanostructure probe to recycle miRNA-21 and trigger two independent rolling circle transcription reactions to generate two long RNAs, which can partially hybridize with each other to generate large amounts of complete MG RNA aptamers. These RNA aptamers can associate with organic MG dye to produce significantly enhanced fluorescence signals to accomplish ultrasensitive miRNA-21 detection down to 0.9 fM. In addition, this method exhibits high selectivity to distinguish miRNA-21 even with single nucleotide mismatch, and also has potential application capability to monitor different expression levels of miRNA-21 from different cancer cells. The effective collaboration between MG RNA aptamer and rolling circle transcription reaction makes this fluorescent method show the significant advantages of low background signal, high signal-to-noise ratio and high detection sensitivity. It has great potential to be a promising means to achieve label-free and highly sensitive monitoring of other trace biological markers via a simple change of target sequence.


Assuntos
Aptâmeros de Nucleotídeos , MicroRNAs , Neoplasias , MicroRNAs/genética , Aptâmeros de Nucleotídeos/genética , Aptâmeros de Nucleotídeos/química , Limite de Detecção , DNA/química , Sondas de DNA/química , Corantes Fluorescentes/química , Neoplasias/diagnóstico , Neoplasias/genética
12.
Beijing Da Xue Xue Bao Yi Xue Ban ; 45(6): 933-7, 2013 Dec 18.
Artigo em Zh | MEDLINE | ID: mdl-24343077

RESUMO

OBJECTIVE: To explore the effect of sleep duration including napping, night sleep and total sleep duration on cognitive functions among preschoolers. METHODS: The samples consisted of 94 preschoolers, aged from 2.58 to 6.75 years, from Hangzhou and Beijing. Peabody Picture Vocabulary Test-Revised (PPVT-R), Picture Deletion Task for Preschoolers (PDTP) and Spatial Working Memory Test were applied to assess the cognitive functions of these preschoolers. Basic demographic information and sleep information were collected with self-made questionnaires. RESULTS: The results of the present study indicated that among all the participants, there were significant grade differences in napping duration and total sleep duration (F0.05(3, 90)=6.346, P=0.001; F0.05(3, 90)=2.925, P=0.038). The total sleep duration was decreased with age. However, the night sleep duration was not changed significantly with age. The correlations between the night sleep and total sleep duration and the scores of attention and working memory were significantly positive (r=0.202-0.282). No significant correlations were noted between the napping and all the scores of cognitive tests. The regression analysis showed that the total sleep duration especially the night sleep duration could well explain the variance of attention and working memory. CONCLUSION: Total sleep duration, especially night sleep duration may have great impact on preschoolers' cognitive functions, such as attention and working memory. Enough sound night sleep may help to promote the cognitive functions of the target population.


Assuntos
Cognição/fisiologia , Sono/fisiologia , Atenção/fisiologia , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Memória/fisiologia , Polissonografia , Distribuição Aleatória
13.
Anal Chim Acta ; 1238: 340643, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36464454

RESUMO

Accurate and ultrasensitive detection of biomarkers is significance for the diagnosis of diseases at early stage. For this purpose, we herein develop a bidirectional dynamic DNA nano-device for amplified fluorescent detection of tumor marker of mucin 1 (MUC1). The nano-device is constructed by immobilizing two sets of DNA cascade catalytic probes on two opposite directions of a single-stranded DNA tracker to limit probe reactants to a compact space. Once target MUC1 binds to the aptamer sequence, the initiator DNA locked in the duplex DNA substrate can be released to induce DNA-initiated cascade hybridization reactions (DCHRs) simultaneously in two opposite directions along the tracker DNA, accompanying the displacement of two quencher labeled-DNA intermediate initiators to facilitate successively execution of DCHRs on the DNA nano-devices, which results in the separation of fluorophore (FAM) and quencher (Dabycl) to produce substantially recovered fluorescent signals for rapid and sensitive detection of MUC1 with a detection limit down to 0.18 pM. In addition, this strategy also exhibits high selectivity against other interfering proteins and potential application capacity in real serum samples, indicating its promising application prospects in disease diagnosis and treatment.


Assuntos
DNA , Mucina-1 , Oligonucleotídeos , Biomarcadores Tumorais , Corantes Fluorescentes
14.
Chem Sci ; 13(37): 11132-11139, 2022 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-36320481

RESUMO

The targeted and direct intracellular delivery of proteins plays critical roles in biological research and disease treatments, yet remains highly challenging. Current solutions to such a challenge are limited by the modification of proteins that may potentially alter protein functions inside cells or the lack of targeting capability. Herein, we develop a stimulus-responsive and bivalent aptamer hexahedron DNA framework (HDF) for the targeted and direct delivery of native therapeutic proteins into cancer cells. The unmodified proteins are caged inside the HDF nanostructures assembled from six programmable single stranded DNAs to protect the proteins from degradation by cathepsins and enhance their targeting capability and delivery efficiency with the nanostructure-integrated aptamers. In addition, the protein drugs can be selectively released from the HDF nanostructures by the intracellular ATP molecules to induce tumor cell apoptosis, highlighting their promising application potential for cell biology and precise protein medicines.

15.
Anal Chim Acta ; 1197: 339521, 2022 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-35168722

RESUMO

MicroRNAs (miRNA) are closely associated with the development of diseases in life processes, and the sensitive detection of microRNA biomarkers is beneficial to disease diagnosis and treatment at early stage. Herein, by coupling the target sequence recycling with the primer exchange reaction (PER), a highly sensitive and non-label approach is constructed to detect miRNA-122, the biomarker for drug-induced liver injury. The target sequence cyclically displaces two hairpins on the DNA track via toehold-mediated strand displacement reactions with the assistance of the fuel DNA. The released hairpins further bind the primer to trigger the polymerase-aided PER process for the yield of plenty of G-quadruplex sequences, which then combine with the thioflavin T to drastically enhance its fluorescence for sensing miRNA-122 with a low 49.4 fM detection limit. Highly specific discrimination of the target miRNA-122 can also be realized with the proposed method. Because of the non-label format, high selectivity and sensitivity, such a method can be a convenient and universal means for sensing various biomarkers for disease diagnosis at the early stages.


Assuntos
Técnicas Biossensoriais , Quadruplex G , MicroRNAs , Biomarcadores , DNA , Limite de Detecção , Técnicas de Amplificação de Ácido Nucleico
16.
Anal Chim Acta ; 1204: 339730, 2022 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-35397905

RESUMO

Simple, selective and sensitive monitoring of antibiotic residues in food is essential for food safety and human health because of its side effects upon inappropriate usage. Here, with a new label- and enzyme-free significant signal enhancement approach by the coupling of catalytic hairpin assembly (CHA) with nonlinear hybridization chain reaction (nHCR), we developed a fluorescence aptamer sensor for the detection of trace kanamycin in milk samples with high selectivity and sensitivity. The binding of the target kanamycin to the aptamer probe could initiate the CHA between two hairpins for the formation of partial DNA duplexes, which further triggered the nHCR of other three hairpins to yield branched DNA complexes with a multitude of active G-quadruplex structures. The subsequent intercalation of the organic dye, thioflavin T, into G-quadruplex structures resulted in significantly enhanced fluorescence responses for realizing sensitive sensing of kanamycin in the dynamic range of 0.1-300 nM with a detection limit of 46.1 pM. Besides, this strategy could also achieve the monitoring of kanamycin selectively in spiked milk samples. With features of high sensitivity and simplicity in a non-enzyme/label fashion, our signal amplification strategy has high potentials for establishing sensitive and convenient means to monitor various antibiotics.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Antibacterianos , Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , DNA/química , DNA/genética , Humanos , Canamicina , Limite de Detecção , Técnicas de Amplificação de Ácido Nucleico/métodos , Hibridização de Ácido Nucleico
17.
J Med Case Rep ; 16(1): 381, 2022 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-36258245

RESUMO

BACKGROUND: Atrial fibrillation is one of the most common arrhythmias. The main thrombotic complication of arterial fibrillation is ischemic stroke, but it can also cause acute renal infarction from embolization. The low incidence and nonspecific clinical manifestations of acute renal infarction make it difficult to diagnose, often leading to either delayed diagnosis or misdiagnosis. Due to its rarity, more efficient treatment guidelines are helpful for the management of acute renal infarction related to the thromboembolic complication of arterial fibrillation. CASE REPORTS: We report a case of acute renal infarction due to underlying arterial fibrillation, where a novel interventional therapeutic method was used. A 66-year-old Chinese man with arterial fibrillation, not on anticoagulation due to the patient's preference, and coronary artery disease post-percutaneous coronary intervention to left anterior descending artery about 1 year ago, was currently on dual antiplatelet therapy. He suddenly developed intermittent and sharp left-sided abdominal pain and was found to have an acute left renal infarction on computed tomography scan. Angiogram showed acute occlusion of the left renal artery due to thromboembolism. For this patient, a combination method of local thrombus aspiration, angioplasty, and infusion of nitroglycerin and diltiazem were used, restoring blood flow to the left kidney. After recovery, the patient was discharged on aspirin, clopidogrel, and warfarin. At 6 months follow-up, there was no residual kidney dysfunction. CONCLUSIONS: Acute renal infarction from thromboembolism is a rare but serious complication of arterial fibrillation. More efficient and different options for intervention methods will benefit the treatment of this disease. Here, we report a combination therapeutic method that has not been used in acute renal infarction associated with arterial fibrillation, and which restored renal perfusion and prevented long-term kidney injury.


Assuntos
Fibrilação Atrial , Tromboembolia , Trombose , Masculino , Humanos , Idoso , Fibrilação Atrial/complicações , Fibrilação Atrial/tratamento farmacológico , Varfarina/uso terapêutico , Clopidogrel/uso terapêutico , Inibidores da Agregação Plaquetária/uso terapêutico , Diltiazem/uso terapêutico , Nitroglicerina/uso terapêutico , Tromboembolia/complicações , Tromboembolia/tratamento farmacológico , Infarto/diagnóstico por imagem , Infarto/etiologia , Infarto/terapia , Aspirina/uso terapêutico , Trombose/complicações , Anticoagulantes/uso terapêutico , Dor Abdominal/etiologia , Dor Abdominal/tratamento farmacológico
18.
Anal Chim Acta ; 1148: 238195, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33516378

RESUMO

Accurate and sensitive monitoring of the abused antibiotics is vital because excessive antibiotics in human body can cause toxicity to kidney or lead to potential loss of hearing. In this work, we described a label-free and highly sensitive fluorescent aptasensing platform for detecting kanamycin in milk samples based on the synchronization signal amplification of primer exchange reaction (PER) and metal-ion dependent DNAzyme. The target kanamycin binds the aptamer sequence hybridized on a hairpin template and initiates PER for autonomous synthesis of Mg2+-dependent DNAzyme sequences with aid of Bst-DNA polymerase at isothermal conditions. Such a synthesis process can be repeated many times to produce lots of DNAzymes to cyclically cleave the rA site in the signal hairpin substrates under the assistance of Mg2+ cofactor to liberate numerous free G-quadruplex fragments. The organic dye thioflavin T (ThT) further associates with these G-quadruplex fragments to yield substantially intensified fluorescence for sensitive detection of kanamycin with a low detection limit of 0.36 nM. In addition, the developed aptamer sensing method also shows a good selectivity for kanamycin against other interfering antibiotics, and can realize the monitoring of kanamycin added in milk samples, highlighting its potential for sensitive monitoring of trace amount of kanamycin for food safety applications.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , DNA Catalítico , Quadruplex G , Animais , DNA Catalítico/genética , Humanos , Canamicina , Limite de Detecção , Leite
19.
Chem Sci ; 11(33): 8966-8972, 2020 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-34123151

RESUMO

DNAzymes exhibit high potential as gene silencing agents for therapeutic applications. Such purposes, however, are significantly challenged by the targeted and successful delivery of unmodified DNAzymes into cells with minimal side effects. Here, we set out to formulate and demonstrate a new stimuli-responsive and constrained aptamer/DNAzyme (Apt/Dz) catenane nanostructure for highly specific gene silencing. The rational design of the Apt/Dz catenane nanostructure with the respective integration of the aptamer sequence and the completely closed catenane format enables both the targeted capability and significantly improved nuclease resistance, facilitating the stable and targeted delivery of unmodified Dz into cancer cells. Moreover, the Dz enzymatic activity in the constrained structure can only be conditionally regulated by the specific intracellular mRNA sequences to silence the target gene with highly reduced side effects. Results show that the Apt/Dz catenane nanostructure can effectively inhibit the expression of the target gene and the proliferation of cancer cells with high specificity.

20.
Dalton Trans ; 49(6): 1794-1802, 2020 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-31976996

RESUMO

MnV2O6 is a promising anode material for lithium ion batteries with high theoretical specific capacity, abundant reserves and inexpensive constituent elements. However, in the process of lithization and de-lithization, the MnV2O6 anode material will form an amorphous phase, leading to collapse of its original layered structure; this greatly decreases its lithium storage capacity and specific capacity and affects its long-term cycle performance. In this study, 2D accordion-like MnV2O6 nanosheets with Co-doping are obtained via a hydrothermal route. The cobalt ions partially replace the positions of the manganese ions, and the emergence of Co3+ ions is inferred to induce the formation of a built-in electric field in the electrode to enhance the electrochemical behaviour of MnV2O6, presenting a high capacity of 1005.9 mA h g-1 after hundreds of cycles. The capacitive contribution to the total capacity is investigated to obtain insight into the kinetic analysis of its electrochemical behaviour. This study sheds light on an effective strategy to obtain excellent electrochemical behavior of MnV2O6-based materials and other transition metal oxides as electrodes for lithium storage.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA