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1.
Sheng Wu Gong Cheng Xue Bao ; 35(9): 1581-1589, 2019 Sep 25.
Artigo em Chinês | MEDLINE | ID: mdl-31559741

RESUMO

As the main factor leading to foodborne illnesses, foodborne pathogens have been attached great importance by people. The development of simple, rapid, high-sensitivity and low-cost food-borne pathogen detection methods is of great significance in reducing the incidence of foodborne diseases. Biosensor technology is a new micro-analysis technology developed by multi-disciplinary cross-infiltration. It has the characteristics of high sensitivity and fast analysis speed, and is widely used in the detection of food-borne pathogens. This paper introduces the basic principles of biosensors, summarizes the application of common biosensors in the detection of foodborne pathogens, and prospects for future development.


Assuntos
Técnicas Biossensoriais , Doenças Transmitidas por Alimentos , Microbiologia de Alimentos , Humanos
2.
Adv Clin Chem ; 92: 1-57, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31472751

RESUMO

Immunosensors are compact tools on which antibody and antigen interactions are formed. The specific interaction between antibody and antigen is detected by using a transducer and an electrical signal is measured. This specific interaction between these molecules makes immunosensor very attractive for several applications in different fields. Electrochemical immunosensors are successful devices in selective and sensitive detection of several analytes. Electrochemical transducing methods such as voltammetric, potentiometric, conductometric or impedimetric have been utilized in different applications due to their excellent properties such as being low-cost, sensitivity and simplicity. In this chapter, the fundamentals of electrochemical immunosensors are summarized and different applications in food, environmental and clinical analyses are investigated and discussed.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Humanos , Imunoensaio
3.
Chem Asian J ; 14(19): 3240-3250, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31508892

RESUMO

With the rapid development of nanoscience and nanotechnology, various types of functional nanoreactors have been designed for diverse applications. Here, the recent evolution of the rational design of nanoreactors for chemical synthesis and biomedical applications are briefly summarized and discussed. The presence of nanoreactors provides constrained space isolated from the surrounding environment. Scientists are committed to studying changes in chemical reactions when the reaction system is confined to the nanosized space. Nanoreactors accelerate the reaction rate and even change mechanism of some chemical reactions. Cells and organelles as natural nanoreactors are also discussed. The development of intracellular synthesis makes it possible to realize various applications in biomedicine. The challenges on the rational design of nanoreactors and perspectives are also discussed.


Assuntos
Nanotecnologia , Tecnologia Biomédica , Técnicas Biossensoriais/métodos , Química Click , Nanopartículas/química , Polímeros
4.
Chem Commun (Camb) ; 55(76): 11442-11445, 2019 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-31486469

RESUMO

Plasmonic resonance energy transfer (PRET) from a Au nanosphere (AuNS) to a quantum dot (QD) is discovered at the single particle level. A homogenous immunoassay based on this PRET is verified using a prostate specific antigen (PSA) as an example. The limit of detection of the PSA is determined to be 0.2 fM.


Assuntos
Técnicas Biossensoriais , Transferência Ressonante de Energia de Fluorescência , Ouro/química , Imunoensaio , Nanopartículas Metálicas/química , Pontos Quânticos/química , Albuminas/análise , Aminoácidos/sangue , Animais , Ânions/sangue , Biomarcadores/sangue , Cátions/sangue , Galinhas , Humanos
5.
J Agric Food Chem ; 67(40): 11244-11255, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31532667

RESUMO

Evaluation of acetylcholinesterase (AChE) activity and determination of organophosphorus pesticides (OPs) are of great importance for the clinical diagnosis of several serious diseases correlated with their variations in human blood serum. In this study, a highly selective and sensitive ratiometric fluorescent probe was innovatively fabricated for the evaluation of AChE activity and the determination of OPs in tap water and food on the basis of the inner filter effect (IFE) between nitrogen-doped carbon dots (N-CDs) and 2,3-diaminophenazine (DAP). N-CDs were synthesized via a one-pot hydrothermal method by using pancreatin and 1,2-ethanediamine as precursors. N-CDs showed excellent fluorescence properties and negligible cytotoxicity on human cervical carcinoma HeLa cells and human embryonic kidney 293T cells, suggesting their further biological applications. Upon the addition of AChE and choline oxidase, acetylcholine was catalyzed to produce choline that was further oxidized to produce H2O2. In the presence of horseradish peroxidase, o-phenylenediamine reacted with H2O2 to produce fluorescent DAP. Therefore, a ratiometric fluorescent probing platform existed via IFE between N-CDs with a fluorescence signal at 450 nm and DAP with a fluorescence signal at 574 nm. OPs irreversibly impeded the catalytic activity of AChE, finally leading to the decrease of DAP amount and the variation of ratiometric fluorescent signal. Under optimal conditions, such a fluorescent probe showed relatively low detection limits of 0.38 U/L for AChE, 3.2 ppb for dichlorvos, and 13 ppb for methyl-parathion. Practical application of this ratiometric fluorescent probe to detect OPs was further verified in tap water and food samples with satisfying results that were highly consisted with the results obtained by GC-MS.


Assuntos
Acetilcolinesterase/química , Técnicas Biossensoriais/métodos , Carbono/química , Corantes Fluorescentes/química , Contaminação de Alimentos/análise , Compostos Organofosforados/análise , Praguicidas/análise , Poluentes Químicos da Água/análise , Fluorescência , Água Doce/análise , Células HeLa , Humanos , Limite de Detecção , Pontos Quânticos/química
6.
Chem Commun (Camb) ; 55(79): 11924-11927, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31528965

RESUMO

We report a novel ditopic Gd(iii)-based probe selective to zwitterionic amino acid neurotransmitters (ZNTs) crafted for ratiometric MRI imaging. The probe displayed increased binding affinity to ZNTs and non-synchronized concentration-dependent changes of the r1- and r2-relaxivity. Through the application of a T2/T1 weighted MRI strategy, we demonstrated signal enhancement for cooperatively bound glutamate and γ-aminobutyric acid ZNTs over competitive hydrogencarbonate, which remained MR silent.


Assuntos
Aminoácidos/química , Meios de Contraste/química , Complexos de Coordenação/química , Gadolínio/química , Imagem por Ressonância Magnética/métodos , Neurotransmissores/análise , Bicarbonatos/análise , Técnicas Biossensoriais/métodos , Ácido Glutâmico/análise , Ligantes , Compostos Macrocíclicos/química , Peso Molecular , Ácido gama-Aminobutírico/análise
7.
Chem Commun (Camb) ; 55(79): 11932-11935, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31531427

RESUMO

An enzyme-free DNA circuit was designed for the amplified detection of Cd2+ based on hairpin probe-mediated toehold binding and branch migration. A Cd2+-specific aptamer was used to recognize Cd2+ and a G-quadruplex was used to report the detection signal. The assay is sensitive, with a detection limit of 5 pM.


Assuntos
Aptâmeros de Nucleotídeos/química , Cádmio/análise , DNA/química , Técnicas Biossensoriais/métodos , Corantes Fluorescentes/química , Quadruplex G , Limite de Detecção , Técnicas de Amplificação de Ácido Nucleico , Sensibilidade e Especificidade , Espectrometria de Fluorescência
8.
Chem Commun (Camb) ; 55(77): 11551-11554, 2019 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-31490470

RESUMO

A novel ratiometric electrochemiluminescence (ECL)-electrochemical (EC) hybrid biosensor with a high accuracy and reproducibility was fabricated for the ultrasensitive detection of miRNA-133a. With the help of a DNA tetrahedron nanostructure and hybridization chain reaction dual amplification strategy, the detection limit of 12.17 aM for miRNA-133a was obtained.


Assuntos
Técnicas Biossensoriais/métodos , DNA/química , MicroRNAs/análise , Nanoestruturas/química , 2,2'-Dipiridil/análogos & derivados , 2,2'-Dipiridil/química , Técnicas Biossensoriais/instrumentação , Técnicas Eletroquímicas , Corantes Fluorescentes/química , Humanos , Limite de Detecção , Medições Luminescentes , Azul de Metileno/química , Técnicas de Amplificação de Ácido Nucleico , Conformação de Ácido Nucleico , Hibridização de Ácido Nucleico , Compostos Organometálicos/química
9.
Chem Commun (Camb) ; 55(77): 11543-11546, 2019 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-31490483

RESUMO

In this work, a simulated enzyme inhibition-based strategy was transplanted from natural peroxidase-based sensing methods for colorimetric nanoperoxidase-based biothiol detection. This work might provide some new perspectives for the construction and biomimetic regulation of mimicked biological signalling systems based on nanoperoxidases.


Assuntos
Corantes Fluorescentes/química , Glutationa/análise , Mercúrio/química , Nanopartículas Metálicas/química , Peroxidases/química , Pontos Quânticos/química , Compostos de Sulfidrila/análise , Materiais Biomiméticos/química , Técnicas Biossensoriais/métodos , Carbono/química , Catálise , Colorimetria/métodos , Ouro/química , Peróxido de Hidrogênio/química , Concentração de Íons de Hidrogênio , Limite de Detecção , Oxirredução , Peroxidases/antagonistas & inibidores , Propriedades de Superfície
10.
Chem Commun (Camb) ; 55(67): 9959-9962, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31364996

RESUMO

On the basis of BSA stabilized tetraphenylethylene nanocrystals (BSA-TPE NCs) as aggregation-induced enhanced electrochemiluminescence (ECL) emitters with high ECL efficiency and good biocompatibility, as well as molecular recognition between ß-CD and ferrocene, an ultrasensitive and versatile ECL biosensing platform was constructed to achieve microRNA detection in cancer cells.


Assuntos
Materiais Biocompatíveis/química , Corantes Fluorescentes/química , MicroRNAs/análise , Nanopartículas/química , Soroalbumina Bovina/química , Estilbenos/química , Animais , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Bovinos , Linhagem Celular Tumoral , Técnicas Eletroquímicas , Compostos Ferrosos/química , Humanos , Limite de Detecção , Medições Luminescentes , Metalocenos/química , Sensibilidade e Especificidade , beta-Ciclodextrinas/química
11.
Inorg Chem ; 58(17): 11382-11388, 2019 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-31402664

RESUMO

Enzyme-like metal-organic frameworks (MOFs) are currently one type of starring material in the fields of artificial enzymes and analytical sensing. However, there has been little progress in making use of the MOF structures based on the catalytically active metal center with multiple valences. Herein, we report a mixed-valence Ce-MOF (Ce-BPyDC) that can exhibit both oxidase-like and peroxidase-like activities. Ce-BPyDC was synthesized by a facile hydrothermal method, which preserves the rare coexistence of Ce(III) and Ce(IV) in the MOF structure. The enzymatic studies demonstrated the enzyme-like activities of Ce-BPyDC follow the Michaelis-Menten kinetics and are strongly dependent on temperature, pH, and reaction time. Ce-BPyDC was also revealed to exert high catalytic activity that could transcend horseradish peroxidase and other MOF nanozymes, due to the redox-active Ce(III)/Ce(IV) cycles inside. Furthermore, the simple synthesis, high nanozyme activity, and great stability of Ce-BPyDC motivated us to establish a colorimetric biosensing platform using 3,3',5,5'-tetramethylbenzidine as a color reagent. Adopting this strategy, we established a visual, sensitive, and selective colorimetric method for ascorbic acid (AA) detection, for which the linear interval and limit of detection were 1-20 and 0.28 µM, respectively. The successful AA detection in real juice samples implies the promising use of such mixed-valence MOF nanozymes in food and biomedical samples.


Assuntos
Técnicas Biossensoriais , Cério/química , Colorimetria , Estruturas Metalorgânicas/química , Ácido Ascórbico/análise , Catálise , Concentração de Íons de Hidrogênio , Estruturas Metalorgânicas/síntese química , Temperatura Ambiente
12.
Chem Commun (Camb) ; 55(72): 10677-10680, 2019 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-31424057

RESUMO

Beacon-mediated Exponential Amplification Reaction (BEAR) enables isothermal, exponential signal amplification. BEAR uses only a single enzyme and a single primer. Detection of 0.2 amol of a mitochondrial DNA with a point mutation in less than an hour demonstrates an application of the BEAR technique for nucleic acid research.


Assuntos
Técnicas Biossensoriais , DNA Mitocondrial/análise , DNA Polimerase Dirigida por DNA/química , Técnicas de Amplificação de Ácido Nucleico , DNA Mitocondrial/genética , DNA Polimerase Dirigida por DNA/metabolismo , Mutação Puntual
13.
Chem Commun (Camb) ; 55(72): 10772-10775, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31432820

RESUMO

Herein, a novel photoelectrochemical (PEC) assay was developed for the sensitive detection of C-reactive protein (CRP) based on a zirconium-based metal-organic framework (PCN-777) as the photoelectric material and thioflavin-T (Th-T) as the effective signal sensitizer coupled with rolling circle amplification (RCA).


Assuntos
Benzotiazóis/química , Técnicas Biossensoriais , Proteína C-Reativa/análise , Técnicas Eletroquímicas , Estruturas Metalorgânicas/química , Zircônio/química , Humanos , Processos Fotoquímicos
14.
Chem Commun (Camb) ; 55(70): 10380-10383, 2019 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-31397448

RESUMO

A strategy for the photoelectrochemical detection of miRNA with ultra-low background noise was developed using tungsten diselenide-cysteine-dopamine (WSe2/Cys/DA) as a nanoprobe coupled with mismatched catalytic hairpin assembly target recycling. A superior detection limit of 3.3 aM toward miRNA-221 was achieved.


Assuntos
Cisteína/química , Dopamina/química , Técnicas Eletroquímicas/métodos , MicroRNAs/análise , Sondas Moleculares/química , Nanoestruturas , Processos Fotoquímicos , Selênio/química , Tungstênio/química , Técnicas Biossensoriais , Catálise , Humanos , Limite de Detecção , MicroRNAs/sangue , Estudo de Prova de Conceito
15.
Biomed Khim ; 65(4): 306-310, 2019 Jun.
Artigo em Russo | MEDLINE | ID: mdl-31436171

RESUMO

It becomes increasingly clear that ubiquitination of cellular proteins is not an indispensable prerequisite of their degradation in proteasomes. There are a number of proteins to be eliminated which are not pre-ubiquitinated for their recognition by regulatory subcomplex of 26S proteasome, but which directly interact with the 20S proteasome core particle (20S proteasome). The obligatory precondition for such interaction consists in existence of disordered (hydrophobic) fragments in the target protein. In this study we have investigated the interaction of a number of multifunctional (moonlighting) proteins (glyceraldehyde-3-phosphate dehydrogenase (GAPDH), aldolase, pyruvate kinase) and neurodegeneration-related proteins (a-synuclein, myelin basic protein) with 20S proteasome immobilized on the SPR-biosensor chip and stabilized by means of a bifunctional agent dimethyl pimelimidate (in order to prevent possible dissociation of this subcomplex). Only two of all investigated proteins (aldolase and pyruvate kinase) interacted with the immobilized 20S proteasome (Kd of 8.17´10-7 M and 5.56´10-7 M, respectively). In addition to earlier detected GAPDH ubiquitination, mass spectrometric analysis of the studied proteins revealed the presence of the ubiquitin signature (Lys-e-Gly-Gly) only in aldolase. Oxidation of aldolase and pyruvate kinase, which promotes elimination of proteins via their direct interaction with 20S proteasome, caused a 2-3-fold decrease in their Kd values as comparison with this parameter obtained for the intact proteins. The results of this study provide further evidence for direct interaction of both ubiquitinated proteins (aldolase), and non-ubiquitinated proteins (pyruvate kinase) with the 20S proteasome core particle (20S proteasome). The effectiveness of this interaction is basically equal for the ubiquitinated proteins and non-ubiquitinated proteins.


Assuntos
Técnicas Biossensoriais , Complexo de Endopeptidases do Proteassoma/química , Proteínas Ubiquitinadas/química , Humanos , Ubiquitina , Ubiquitinação
16.
Analyst ; 144(17): 5284-5291, 2019 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-31372627

RESUMO

5,10,15,20-Tetrakis(4-carboxyl phenyl)porphyrin (Por) modified Co(OH)2 deposited on the surface of GO nanocomposites (Por/Co(OH)2/GO) were prepared and characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and XRD. For the first time, H2TCPP/Co(OH)2/GO is found to have enhanced peroxidase-like activity and catalyze the oxidation of the substrate 3,3,5,5-tetramethylbenzidine (TMB) by hydrogen peroxide (H2O2). Notably, the colorless TMB rapidly transformed into blue oxTMB in just 60 s, which was easily observed visually. The catalytic kinetics of H2TCPP/Co(OH)2/GO is in accord with the Michaelis-Menten equation. The catalytic mechanism of H2TCPP/Co(OH)2/GO nanocomposites is attributed to hydroxyl radicals (˙OH), due to decomposition of H2O2, which is verified by using terephthalic acid as a fluorescent probe. What's more, H2O2 can be detected in a wide linear detection range from 5 to 35 mM with a detection limit of 0.385 mM. Furthermore, based on the excellent peroxidase-like activity of H2TCPP/Co(OH)2/GO, a colorimetric sensor is established to sensitively detect glutathione (GSH) in a linear range from 10 to 300 µM with a low detection limit of 9.5 µM.


Assuntos
Cobalto/química , Grafite/química , Hidróxidos/química , Nanocompostos/química , Peroxidases/química , Porfirinas/química , Benzidinas/química , Materiais Biomiméticos , Técnicas Biossensoriais/métodos , Catálise , Glutationa/análise , Peróxido de Hidrogênio/química , Radical Hidroxila/química , Cinética , Limite de Detecção , Oxirredução , Sensibilidade e Especificidade , Propriedades de Superfície
17.
Analyst ; 144(17): 5108-5116, 2019 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-31373337

RESUMO

We report here the influence of antibody immobilization strategy for protein immunosensors on screen printed carbon electrode arrays in terms of antibody binding activity, analytical sensitivity, limit of detection, and stability. Horseradish peroxidase (HRP) was the model analyte with anti-HRP immobilized on the sensors, and HRP activity was used for detection. Covalently immobilized anti-HRP antibodies on electrodes coated with chitosan, electrochemically reduced graphene oxide (rGO), and dense gold nanoparticle (AuNP) films had only 20-30% of the total immobilized antibodies active for binding. Active antibodies increased to 60% with passively adsorbed antibodies on bare electrodes, to 85% with oriented antibodies using protein A covalently immobilized on AuNP-coated carbon electrode, and to 98% when attached to protein A passively adsorbed onto bare electrodes. Passively adsorbed antibodies on bare electrodes lost activity in 1-2 days, but antibodies immobilized using other strategies remained relatively stable after 5 days. Covalent immobilization gave limits of detection (LOD) of 40 fg mL-1, while passively adsorbed antibodies or protein A on carbon electrodes had LODs 4-8 fg mL-1, but were unstable. Sensitivity was highest for antibodies covalently attached to AuNP electrodes (2.40 nA per log pg per mL) that also had highest antibody coverage, and decreased slightly when protein A on AuNP was used to orient antibodies. Passively adsorbed antibodies and oriented antibodies on protein A gave slightly lower sensitivities. Immobilization strategy or antibody orientation did not have a significant effect on LOD, but dynamic range increased as the number of active antibodies on sensor surfaces increased.


Assuntos
Anticorpos Imobilizados/química , Carbono/química , Técnicas Biossensoriais/métodos , Quitosana/química , Técnicas Eletroquímicas/métodos , Eletrodos , Grafite/química , Peroxidase do Rábano Silvestre/química , Imunoensaio/métodos , Limite de Detecção , Oxirredução , Propriedades de Superfície
18.
Analyst ; 144(17): 5098-5107, 2019 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-31373344

RESUMO

Simultaneous detection and regulation of tumor-related genes presents a promising strategy for early diagnosis and treatment of cancer, but achieving this has been a huge challenge for both chemical and biomedical communities. Towards this objective, we have devised a novel aptamer-tethered, DNAzyme-embedded molecular beacon (MB) for multiple functions in cancer cells. In this design, a tumor targeting aptamer was employed to specifically deliver the sensor into cancer cells for target gene detection, and an RNA-cleaving DNAzyme was embedded to realize gene regulation. Both aptamer-tethering and DNAzyme-embedding had little influence on the sensor performance, with a detection limit of ∼2 nM and high specificity. After delivering into tumor cells, our device could monitor the tumor-related genes by producing detectable fluorescence signals, and regulate the gene expression at both mRNA and protein levels as evidenced by the RT-PCR and western blot analyses. This study provides a simple and efficient strategy to rationally combine various functional nucleic acids for multi-functional applications in living cells, which hold great potential for cancer diagnosis and therapy.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , DNA Catalítico/química , Genes Neoplásicos , Linhagem Celular Tumoral , Humanos , Limite de Detecção
19.
Water Sci Technol ; 79(12): 2231-2241, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31411577

RESUMO

Microbial fuel cell (MFC) technology holds enormous potential for inexpensive real-time and onsite testing of water sources. With the intent of defining optimal operational conditions, we investigated the effect of environmental factors (changes in temperature, pH and ionic strength), on the performance of a single chamber miniature MFC sensor. The pH of the influent had the greatest effect on the MFC performance, with a 0.531 ± 0.064 µA cm-2 current variation per unit change of pH. Within the range tested, temperature and ionic strength had only a minor impact (0.010 ± 0.001 µA °C-1 cm-2 and of 0.027 ± 0.003 µA mS-1 cm cm-2 respectively). Under controlled operational conditions, for the first time, we demonstrated the ability of this biosensor to detect one of the most commonly applied pesticides worldwide, atrazine. The sensitivity to atrazine was 1.39 ± 0.26 ppm-1 cm-2, with a detection range of 0.05-0.3 ppm. Guidelines for systematic studies of MFC biosensors for practical applications through a factorial design approach are also provided. Consequently, our work not only enforces the promise of miniature MFC biosensors for organic pollutants detection in waters, but it also provides important directions towards future investigations for infield applications.


Assuntos
Fontes de Energia Bioelétrica , Técnicas Biossensoriais , Praguicidas , Eletrodos
20.
Stud Health Technol Inform ; 264: 1724-1725, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31438312

RESUMO

This paper explains a methodology to improve patient safety through early detecting of HF complications and analyzing HF biomarkers in saliva obtained using a biosensor developed in HEARTEN project. A pilot study was performed in two hospitals in Spain and Italy respectively. A direct correlation was identified between TNF-alpha levels in saliva and weight. The weight gain in HF patients could predict a HF decompensation, consequently TNF-alpha could be a new biomarker of these decompensations.


Assuntos
Insuficiência Cardíaca , Saliva , Fator de Necrose Tumoral alfa/análise , Biomarcadores , Técnicas Biossensoriais , Insuficiência Cardíaca/diagnóstico , Humanos , Itália , Projetos Piloto , Saliva/química , Espanha
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