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1.
Analyst ; 146(16): 5074-5080, 2021 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-34318784

RESUMO

Diabetes mellitus has received much attention because its complications include liver, kidney, eye, heart and cerebrovascular diseases. Thus, it would be highly significant to develop a rapid and efficient method for glucose detection in biological samples. In this work, a point-of-care testing (POCT) method of glucose detection was proposed using a standard colorimetric card for semi-quantitative determination patterns. In the prepared fluorescence color card for glucose, a good linear relationship was acquired by plotting the ratio of the grayscale value (I/I0) versus the logarithm of glucose concentration within 100.0 to 1000.0 µmol L-1, and the LOD of glucose detection was 1.1 µmol L-1. A large number of actual samples (30 serum and 7 urine) were analyzed and the results demonstrated that this method had good potential to be applied in the primary screening of diabetic patients. In addition, this method is universal and can be applied in the simultaneous detection of multiple small molecules. It provides a new strategy for the primary screening of multiple diseases simultaneously, which presents excellent application potential.


Assuntos
Diabetes Mellitus , Testes Imediatos , Colorimetria , Diabetes Mellitus/diagnóstico , Glucose , Humanos , Sistemas Automatizados de Assistência Junto ao Leito
2.
Analyst ; 146(15): 4775-4780, 2021 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-34231558

RESUMO

Cholesterol is an essential compound for human health, and a high or low concentration of cholesterol is closely related to various diseases. Thus, developing a simple method for POCT of cholesterol has great significance in clinical diagnosis. In this work, alginate (Alg) hydrogels with glow-type chemiluminescence (CL) were prepared and applied for rapid and quantitative cholesterol detection via a smartphone. The glow-type CL hydrogels (HRP/COD/luminol/Alg hydrogels) contained luminol as a chemiluminescent reagent, horseradish peroxidase (HRP) and cholesterol oxidase (COD) for enzymatic cascade reactions. The HRP/COD/luminol/Alg hydrogels exhibited outstanding stability, which effectively avoided the enzyme inactivation during long-term storage. Furthermore, the HRP/COD/luminol/Alg hydrogels exhibited longer and more stable glow-type CL. With the help of COD catalytic specificity for cholesterol and bi-enzymatic cascade reactions, the glow-type CL hydrogels realized the specific and sensitive detection of cholesterol. The smartphone was used as a detector instead of a special large instrument for responding to the glow-type CL emission, and a LOD of 7.2 µM was obtained. Therefore, the proposed sensor expands the application of the glow-type CL in POCT and provides an alternative way for cholesterol detection in clinical diagnosis.


Assuntos
Colesterol/análise , Hidrogéis , Testes Imediatos , Peroxidase do Rábano Silvestre , Humanos , Medições Luminescentes , Luminol
3.
Anal Methods ; 13(18): 2092-2098, 2021 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-33870959

RESUMO

Nanosurface energy transfer (NSET)-based sensors have been widely developed using various pairs of nanomaterials including gold nanoparticles (AuNPs) and quantum dots (QDs). However, a low signal to background ratio is one of the most important problems that researchers are continually trying to solve. Herein, we present a 6-mercaptohexanol (MCH) modified MCH/DNA-Au-QD sensor for the detection of nucleic acids and MUC1. Interestingly, an unexpected effect of MCH was found in enhancing the fluorescence recovery ratio, therefore yielding a higher signal to background ratio. Through further investigation, we perceive the enhancement as a result of lowering of the NSET efficiency between free DNA-AuNPs and free DNA-QDs, which arises from the stretching of adsorbed DNA on the surface of AuNPs. The employment of MCH endowed the sensor with a wider linear range from 5 nM to 120 nM and a relatively lower LOD of 1.19 nM in nucleic acid detection, outperforming the original DNA-Au-QD sensor. Furthermore, the application of the sensor can be further extended to MUC1 detection. This study offers a better understanding of the NSET process between QDs and AuNPs and also initiates a new approach for the performance optimization of analogous NSET-based sensors.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Pontos Quânticos , Transferência de Energia , Ouro
4.
Anal Chem ; 93(13): 5606-5611, 2021 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-33764756

RESUMO

When dealing with infectious pathogens, the risk of contamination or infection in the process of detecting them is nonnegligible. Separation-free detection will be beneficial in operation and safety. In this work, we proposed a DNAzyme walker for homogeneous and isothermal detection of enterovirus. The DNAzyme is divided into two inactivate subunits. When the subunit-conjugated antibody binds to the target virus, the activity of the DNAzyme recovers as a result of spatial proximity. The walker propels, and the fluorescence recovers. The final fluorescence intensity of the reaction mixture is related to the concentration of the target virus. The detection limit of this proposed method is 6.6 × 104 copies/mL for EV71 and 4.3 × 104 copies/mL for CVB3, respectively. Besides, this method was applied in detection of EV71 in clinical samples with a satisfactory result. The entire experiment is easy to operate, and the proposed method has great potential for practical use.


Assuntos
DNA Catalítico , Enterovirus Humano A , Enterovirus , Antígenos Virais , Fluorescência
5.
Analyst ; 146(3): 949-955, 2021 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-33245089

RESUMO

High concentration of uric acid is usually related to cardiovascular and cerebrovascular diseases. Developing a simple method for the rapid and efficient detection of uric acid has a great significance in clinical diagnosis. In this work, alginate hydrogel microspheres embedded with CdZnTeS QDs and urate oxidase (Alg@QDs-UOx MSs) were prepared for the first time, and further used for point-of-care testing (POCT) of patients with a high concentration of uric acid. This strategy is mainly based on visual detection of H2O2, the product of uric acid after an enzymatic reaction. The proposed sensor (Alg@QDs-UOx MSs) has several advantages. First, it can reduce the interference of the proteins to the fluorescence of QDs. Second, Alg@QDs-UOx MSs help improve the stability of the CdZnTeS QDs as well as the activity of urate oxidase during storage. Third, it is easy to use, has fast response speed, and is of low cost. Therefore, the proposed sensor shows good application prospects. Simply through the built-in camera of a smartphone, we can visualize the urine samples from patients with a high concentration of uric acid within 10 minutes, and the accuracy rates were 100%. In the range of 100.0 µM to 900.0 µM, the I/I0 values and uric acid concentrations are in a great linear relationship (R2 = 0.9973), indicating that this method can be employed for quantitative analysis of uric acid in human urine (<10 mM). The limit of detection (LOD) is 20.3 µM.


Assuntos
Urato Oxidase , Ácido Úrico , Alginatos , Cádmio , Humanos , Hidrogéis , Peróxido de Hidrogênio , Microesferas , Testes Imediatos , Telúrio , Zinco
6.
Anal Chem ; 93(2): 777-783, 2021 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-33300344

RESUMO

Bioorthogonal chemistry has been considered as a powerful tool for biomolecule labeling due to its site specificity, moderate reaction conditions, high yield, and simple post-treatment. Covalent coupling is commonly used to modify quantum dots (QDs) with bioorthogonal functional group (azide or cycloalkyne), but it has a negative effect in the decrease of QDs' quantum yield and stability and increase of QDs' hydrodynamic diameter. To overcome these disadvantages, we propose a novel method for the preparation of two kinds of clickable QDs by the strong interaction of -SH with metal ions. One system involves azide-DNA-functionalized QDs, which are used for bioconjugation with dibenzocyclooctyne (DBCO)-modified glucose oxidase (GOx) to form a GOx-QDs complex. After bioconjugation, the stability of QDs was improved, and the activity of GOx was also enhanced. The GOx-QDs complex was used for rapid detection of blood glucose by spectroscopy, naked eye, and paper-based analytical devices. The second system involves DBCO-DNA-functionalized QDs, which are used for an in situ bioorthogonal labeling of HeLa cells through metabolic oligosaccharide engineering. Therefore, these clickable QDs based on DNA functionalization can be applied for rapid and effective labeling of biomolecules of interest.


Assuntos
Técnicas Biossensoriais/métodos , Pontos Quânticos , Glicemia , Compostos de Cádmio/química , Diabetes Mellitus/sangue , Glucose/química , Glucose/metabolismo , Células HeLa , Humanos , Telúrio/química , Zinco/química
7.
Mikrochim Acta ; 187(4): 252, 2020 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-32232585

RESUMO

A homogeneous fluorescent immunoassay is described for the determination of alpha fetoprotein (AFP) relying on the interaction between copper ion complex and quantum dots (QDs). The copper ion complex-labelled antibody can be employed as a quencher of fluorescence of QDs and capture probe of AFP in homogeneous solution. The labelled antibody is mixed with QDs to form the immune ensemble probe. Upon the addition of AFP, the labelled antibody is stripped away from QDs by antigen-antibody combination leading to the increase in the fluorescence signal. Thus, the determination of AFP can be realized by fluorometry (best measured at excitation/emission wavelengths of 360/520 nm). The fluorescence intensity shows a good linear relationship with the AFP concentration ranging from 40 to 640 ng mL-1, and the LOD is 26 ng mL-1. The proposed method provides a new approach to incorporate metal complexes into QD-based biomolecule sensing. Graphical abstract Schematic presentation of a fluorescent probe comprised of quantum dots and antibody labelled with copper ion complex for homogeneous immunoassay of α-fetoprotein. The target antigen can break up the ground state QD/labelled antibody complex to set free the fluorescent QDs.

8.
Onco Targets Ther ; 13: 989-1000, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32099402

RESUMO

Background: Glioma is one of the most common malignant tumors. Glioblastoma (grade IV) is considered the most malignant form of human brain tumors. Maternal expression gene 3 (Meg3) encodes a non-coding RNA (ncRNA) that plays an important role in the development and progression of cancer. However, the role of Meg3 in glioma cells remains largely unclear. Methods: Reverse transcription-quantitative (RT-q) PCR was conducted to evaluate the mRNA expression related to cell autophagy and EMT while protein expression was detected by Western blotting. Staining of acidic vacuoles and immunofluorescence staining were used to detect autophagy. The ability of cells to migrate and invade was detected by Transwell migration and invasion assays. Results: In the present study, it was found that the overexpression of Meg3 induced EMT, migration and invasion of glioma cells, whereas Meg3 overexpression induced autophagy of glioma cells. More importantly, the inhibition of autophagy impaired the EMT of glioma cells. In addition, Meg3-induced EMT, migration and invasion could be partially reversed by autophagy inhibitors, chloroquine (CQ) and Lys05, in glioma cells. Conclusion: All data suggest that Meg3 induces EMT and invasion of glioma cells via autophagy. Overall, the findings of the present study demonstrate the importance of Meg3 in the molecular etiology of glioma, which also indicate its potential applications in the treatment of glioma.

9.
Mol Biol Rep ; 47(1): 433-441, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31637620

RESUMO

Glioma is the most aggressive primary brain tumor. We have previously provided evidence that IFITM3 promoted glioma cells migration. However, the mechanism of how IFITM3 regulates glioma cells invasion and whether IFITM3 participates in TGF-ß-mediated glioma invasion are still unknown. In this paper, we proved that IFITM3 was notably up-regulated in glioma tissues. Knockdown of IFITM3 suppressed STAT3 phosphorylation in vitro, and a specific STAT3 inhibitor AG490 reversed IFITM3-induced invasion of glioma cells. Furthermore, IFITM3 expression was induced by TGF-ß in glioma and IFITM3 knockdown abolished TGF-ß-mediated glioma cells invasion. Collectively, the results indicate that IFITM3/STAT3 axis may promote TGF-ß-induced glioma cells invasion. This study provided some suggestions for the clinical treatment of the brain tumor.


Assuntos
Glioma/metabolismo , Proteínas de Membrana/metabolismo , Proteínas de Ligação a RNA/metabolismo , Fator de Transcrição STAT3/metabolismo , Adulto , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Feminino , Regulação Neoplásica da Expressão Gênica/genética , Glioma/genética , Humanos , Masculino , Proteínas de Membrana/genética , Pessoa de Meia-Idade , Fosforilação , Proteínas de Ligação a RNA/genética , Fator de Transcrição STAT3/genética , Ativação Transcricional/genética , Fator de Crescimento Transformador beta/genética , Fator de Crescimento Transformador beta/metabolismo , Tirfostinas/farmacologia
10.
J Mater Chem B ; 8(1): 9-17, 2020 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-31750850

RESUMO

Over the past 10 years, DNA functionalized quantum dots (QDs) have attracted considerable attention in sensing and imaging of disease-relevant biological targets, as well as cancer therapy. Considerable efforts have been devoted to obtaining DNA functionalized QDs with enhanced stability and quantum yield. Here, we focus on a one-pot method, in which phosphorothioate-modified DNA is used as the co-ligand on the basis of the strong binding of sulfur and Cd2+. After a short summary of the preparation of DNA-templated QDs, versatile bioapplications based on the constructed ratiometric fluorescent probes, nanobeacons and multiple bottom-up assemblies will be discussed. A substantial part of the review will focus on these applications, ranging from small molecule, biological macromolecule, cancer cell and pathogen sensing to in vitro and in vivo imaging. Besides, drug or siRNA delivery based on DNA-templated QD assemblies will also be briefly discussed here.


Assuntos
Técnicas Biossensoriais , Diagnóstico por Imagem , Neoplasias , Fármacos Fotossensibilizantes/uso terapêutico , Pontos Quânticos/uso terapêutico , Antineoplásicos/administração & dosagem , Linhagem Celular , DNA/uso terapêutico , Portadores de Fármacos/uso terapêutico , Humanos , Neoplasias/diagnóstico por imagem , Neoplasias/terapia
11.
Anal Chem ; 91(23): 15099-15106, 2019 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-31698906

RESUMO

Detection of viruses with high sensitivity is critical for the prevention and treatment of the related disease. Two homogeneous target-induced cascade amplification methods were proposed for the detection of enterovirus 71 and coxsackievirus B3. These methods both employ DNAzyme but differ in the way in which the DNAzyme is amplified. In the hybridization chain reaction (HCR)-based strategy, the DNAzyme is assembled by hairpin DNA strands, while in the rolling circle amplification (RCA)-based strategy, the DNAzyme is synthesized by the polymerase. On the basis of the virion structure, we investigated the effects of using only VP1-antibody or VP1-antibody and VP2-antibody on the detection. And the combination of two kinds of antibodies was found to further improve the performance of the detection. Subsequently, the simultaneous detection of EV71 and CVB3 was achieved by the RCA-based strategy. And the proposed methods were also applied in clinical samples analysis with a satisfactory result, showing great potential for applications in virus detection.


Assuntos
DNA Catalítico/biossíntese , Enterovirus Humano A/isolamento & purificação , Enterovirus Humano B/isolamento & purificação , Técnicas de Amplificação de Ácido Nucleico/métodos , Anticorpos Antivirais , DNA Catalítico/metabolismo , Humanos
12.
Nanoscale ; 11(37): 17179-17194, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31532431

RESUMO

Organic-inorganic hybrid nanoflowers (NF) with sizes or features on a nanoscale are a class of flower-shaped nanomaterials self-assembled from metal ions and organic components. Here, to be more specific, the organic components mainly refer to biomolecules ranging from proteins, peptides, and amino acids to DNA/RNA. Beyond their pleasing aesthetics, their unique properties and integrated functions have attracted widespread interest and made them promising candidates in the application of biomedical areas. Great efforts have been made to design and synthesize versatile functional hybrid nanoflowers. In this review, we begin with the clarification of versatile recently reported hybrid nanoflowers according to the types of metal ions and biomolecules employed. To highlight the design of organic-inorganic hybrid nanoflowers, their synthetic methods and mechanisms, structural and biological characteristics are discussed. After that, the state-of-the-art applications of hybrid nanoflowers in biomedical fields including biosensing, biocatalysis, and cancer therapy are demonstrated. In the end, we discuss the prospects of organic-inorganic hybrid nanoflowers and highlight the challenges and opportunities for future research.


Assuntos
Biocatálise , Biopolímeros/química , Técnicas Biossensoriais , Metais/química , Nanoestruturas/química , Animais , Humanos
13.
Anal Chim Acta ; 1084: 116-122, 2019 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-31519230

RESUMO

The viral capsid protein p24 of human immunodeficiency virus is expressed at different level during viral invasion. Detection of p24 is of great importance in acquired immunodeficiency syndrome monitoring and therapy. A ratiometric probe that is easily-synthesized was constructed based on self-assembled fluorescent Ce(Ⅲ) and fluorescein. Fluorescein was used as reference. Hydrogen peroxide quenches the fluorescence of the Ce(III) easily but does not quench the fluorescence of fluorescein. The mechanism of reaction was discussed. Benefiting from the sensitive response to hydrogen peroxide, this probe was applied for p24 detection in enzyme linked immunoassay. The fluorescence ratio was in a good linear relationship with the concentration of p24, and the detection limit was 1.1 pg mL-1. This proposed method has shown potential in virus detection with easy operation.


Assuntos
Cério/química , Complexos de Coordenação/química , Corantes Fluorescentes/química , Antígenos HIV/análise , Infecções por HIV/diagnóstico por imagem , Polímeros/química , Complexos de Coordenação/síntese química , Corantes Fluorescentes/síntese química , Humanos
14.
J Exp Clin Cancer Res ; 38(1): 366, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31429770

RESUMO

BACKGROUND: The epithelial-to-mesenchymal transition (EMT) has been linked to the regulation of glioma progression. However, the underlying signaling mechanisms that regulate EMT are poorly understood. METHODS: Quantitative real-time PCR (RT-qPCR) and western blot were performed to detect the expression of MeCP2 in glioma tissues and cell lines. MeCP2 functions were tested with cell immunofluorescence staining and western blot. For in vivo experiments, mouse xenograft model was used to investigate the effects of MeCP2 on glioma. ChIP and Co-IP were used to detect the relationships among MeCP2, miR-200c and Suv39H1. RESULTS: In this study, we found that MeCP2 was frequently up-regulated in human glioma tissues and cell lines. MeCP2 knockdown remarkably induced cell epithelial phenotype and inhibited mesenchymal marker ZEB1 and ZEB2 in vitro and in vivo. In addition, MeCP2 in glioma tissues was negatively correlated with miR-200c expression, and miR-200c overexpression partially abrogated mesenchymal phenotype induced by MeCP2. More importantly, we showed that MeCP2 recruited H3K9 to the promoter of miR-200c by interacting with SUV39H1, resulting in EMT of glioma cells. CONCLUSIONS: This study for the first time reveals MeCP2 as a novel regulator of EMT in glioma and suggest that MeCP2 inhibition may represent a promising therapeutic option for suppressing EMT in glioma.


Assuntos
Biomarcadores Tumorais/metabolismo , Neoplasias Encefálicas/patologia , Repressão Epigenética , Transição Epitelial-Mesenquimal , Glioma/patologia , Proteína 2 de Ligação a Metil-CpG/metabolismo , MicroRNAs/genética , Animais , Apoptose , Biomarcadores Tumorais/genética , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Ciclo Celular , Movimento Celular , Proliferação de Células , Feminino , Seguimentos , Regulação Neoplásica da Expressão Gênica , Glioma/genética , Glioma/metabolismo , Humanos , Proteína 2 de Ligação a Metil-CpG/genética , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Prognóstico , Transdução de Sinais , Taxa de Sobrevida , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
15.
J Am Chem Soc ; 141(34): 13454-13458, 2019 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-31339040

RESUMO

Detection and imaging RNAs in live cells is in high demand. Methodology for such a purpose is still a challenge, particularly for single RNA detection and imaging in live cells. In this study, a type of quantum dot (QD) nanobeacon with controllable valencies was constructed by precisely conjugating the black hole quencher (BHQ1) and phosphorothioate comodified DNA onto CdTe:Zn2+ QDs via a one-pot hydrothermal method. The nanobeacon with only one conjugated DNA was used to label and detect low-abundance nucleic acids in live cells, and single HIV-1 RNAs were detected and imaged in live HIV-1 integrated cells. Additionally, QD nanobeacon-labeled HIV-1 genomic RNAs were encapsulated in progeny viral particles, which can be used to track the uncoating process of single viruses. The current study provides a platform for nucleic acid labeling and imaging with high sensitivity, being especially meaningful for tracking of individual RNAs in live cells.


Assuntos
Compostos de Cádmio/química , DNA/química , Imagem Óptica/métodos , Pontos Quânticos/química , RNA/análise , Telúrio/química , Linhagem Celular , HIV-1/isolamento & purificação , Humanos , Microscopia Confocal/métodos , RNA Viral/análise
16.
J Cell Physiol ; 234(12): 23302-23314, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31140621

RESUMO

Glioma constitutes the most aggressive primary intracranial malignancy in adults. We previously showed that long noncoding RNA activated by TGF-ß (lncRNA-ATB) promoted the glioma cells invasion. However, whether lncRNA-ATB is involved in TGF-ß-mediated invasion of glioma cells remains unknown. In this study, quantitative real-time polymerase chain reaction and western blot analysis were used for detecting the mRNA and protein expression of related genes, respectively. Transwell assay was performed to assess the impact of lncRNA-ATB on TGF-ß-induced glioma cells migration and invasion. Immunofluorescence staining was utilized to characterize related protein distribution. Results showed that TGF-ß upregulated lncRNA-ATB expression in glioma LN-18 and U251 cells. Overexpression of lncRNA-ATB activated nuclear factor-κB (NF-κB) pathway and promoted P65 translocation into the nucleus, thus facilitated glioma cells invasion stimulated by TGF-ß. Similarly, lncRNA-ATB markedly enhanced TGF-ß-mediated invasion of glioma cells through activation P38 mitogen-activated protein kinase (P38/MAPK) pathway. Moreover, both the NF-κB selected inhibitor pyrrolidinedithiocarbamate ammonium and P38/MAPK specific inhibitor SB203580 partly reversed lncRNA-ATB induced glioma cells invasion mediated by TGF-ß. Collectively, this study revealed that lncRNA-ATB promotes TGF-ß-induced glioma cell invasion through NF-κB and P38/MAPK pathway and established a detailed framework for understanding the way how lncRNA-ATB performs its function in TGF-ß-mediated glioma invasion.


Assuntos
Neoplasias Encefálicas/patologia , Regulação Neoplásica da Expressão Gênica/genética , Glioma/patologia , RNA Longo não Codificante/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Linhagem Celular Tumoral , Glioma/genética , Glioma/metabolismo , Humanos , Sistema de Sinalização das MAP Quinases/fisiologia , NF-kappa B/metabolismo , Invasividade Neoplásica/genética , RNA Longo não Codificante/genética
17.
Mikrochim Acta ; 186(4): 233, 2019 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-30852673

RESUMO

A fluorometric method is described for the determination of the tumor biomarker mucin 1 (MUC1). It is based on signal amplification of the hybridization chain reaction (HCR), and the interaction between a luminescent ruthenium(II) complex and CdZnTeS quantum dots (QDs). If MUC1 bind to the biotin-labeled aptamer, it will initiate HCR with hairpins H1 and H2 to form a long-range dsDNA. The long nucleic acid chains are then linked on the surface of streptavidin-modified magnetic microparticles (MMPs) through streptavidin-biotin interaction. The luminescent ruthenium(II) complex is then embedded in the long dsDNA linked to the MMPs. Hence, there is little Ru complex in the supernatant after magnetic separation, and the fluorescence of the CdZnTeS QDs (best measured at excitation/emission wavelengths of 350/530 nm) is only slightly quenched. In the absence of target, the fluorescence of the CdZnTeS QDs is strongly quenched. Fluorescence increases linearly in the 0.2-100 ng·mL-1 MUC1 concentration range, and the LOD is 0.13 ng·mL-1 (at S/N = 3). The method was applied to the determination of MUC1 in spiked human serum samples. Graphical abstract A fluorometric turn-on aptasensor for mucin 1 is described that is based on the interaction between a Ru(II) complex and quantum dots (QDs). The detection system includes biotin-labeled aptamer-H0, hairpins H1 and H2, streptavidin-modified magnetic microparticles (MMPs), Ru(bpy)2(dppx)2+ and CdZnTeS QDs.


Assuntos
Aptâmeros de Nucleotídeos/química , Complexos de Coordenação/química , Corantes Fluorescentes/química , Mucina-1/sangue , Pontos Quânticos/química , Aptâmeros de Nucleotídeos/genética , Sequência de Bases , Técnicas Biossensoriais/métodos , DNA/química , DNA/genética , Humanos , Limite de Detecção , Técnicas de Amplificação de Ácido Nucleico , Hibridização de Ácido Nucleico , Rutênio/química , Espectrometria de Fluorescência/métodos
18.
Chem Commun (Camb) ; 55(18): 2660-2663, 2019 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-30742193

RESUMO

A green and facile method is presented for in situ synthesis of a novel photoluminescence-quenching nanopaper with a highly-efficient quenching ability, rapid reaction time and long-term storage. The as-prepared nanopaper is further used to construct an aptasensor platform with high performance, rapidness and robustness.


Assuntos
Escherichia coli/isolamento & purificação , Nanoestruturas/química , Papel , Proteínas/análise , Aptâmeros de Nucleotídeos/química , Citocromos c/química , DNA/química , Escherichia coli/química , Mucina-1/análise , Mucina-1/química , Proteínas/química , Pontos Quânticos/química , Espectrometria de Fluorescência
19.
Anal Bioanal Chem ; 411(18): 4055-4061, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30693369

RESUMO

In this work, a three-dimensional DNA machine based on the isothermal strand-displacement polymerase reaction (ISDPR) has been constructed. The walking behavior of a DNA walker on the obstructive surface of magnetic beads has also been studied by adding different nucleic acid blocks. The "leg" of the DNA walker could hybridize with a hairpin structure DNA named H1 and lead to the opening of it. And the newly exposed stem would interact with a primer. A strand exchange has happened with the assistance of polymerase and dNTPs, so that the "leg" has been displaced and the DNA walker could be pushed to move on the surface. But the nucleic acid blocks could increase steric hindrance and obstruct this process, which is similar to the behavior of human beings walking on craggy paths. Through changing these blocks, such as the structure, the amount, and the length of blocks, the movement of the DNA walker has been controlled. What's more, the results of its application for DNA detection are satisfactory. The limit of detection is 21.6 pM. Also, this method has been successfully applied in complex biological samples. Graphical abstract ᅟ.


Assuntos
DNA/análise , DNA/química , Imãs , Primers do DNA/química , Eletroforese em Gel de Ágar , Limite de Detecção , Técnicas de Amplificação de Ácido Nucleico/métodos , Conformação de Ácido Nucleico
20.
Anal Chim Acta ; 1047: 208-213, 2019 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-30567651

RESUMO

Alkaline phosphatase (ALP) is a universal and important hydrolase that has been proved to be associated with several diseases. Herein, a simple and effective method was proposed for ALP detection based on the inner filter effect of p-nitrophenol (pNP) on the fluorescence of CdTe/CdS quantum dots (QDs). For the preparation of CdTe/CdS QDs, Na2TeO3 was used as the Te source, and dithiol as the S source and surface ligand. The as-prepared CdTe/CdS QDs show good fluorescence properties, such as high quantum yield (∼80%), and good chemical/photo-stability. pNP is a hydrolysate of p-nitrophenol phosphate disodium salt under the catalysis of ALP, which could effectively quench the fluorescence of QDs due to the absorption spectra of pNP overlaps well with the excitation spectra of the CdTe/CdS QDs. Therefore, the prepared CdTe/CdS QDs could be applied for ALP detection. A good linear relationship ranging from 2.2 to 220 U/L was obtained with the limit of detection as low as 0.34 U/L. In addition, this method was successfully applied for the assay of ALP in human serum with the satisfactory results.


Assuntos
Fosfatase Alcalina/urina , Corantes Fluorescentes/química , Pontos Quânticos/química , Espectrometria de Fluorescência/métodos , Fosfatase Alcalina/química , Compostos de Cádmio/química , Transferência de Energia , Fluorescência , Corantes Fluorescentes/síntese química , Humanos , Limite de Detecção , Nitrofenóis/química , Compostos Organofosforados/química , Sulfetos/química , Telúrio/química
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