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1.
Medicine (Baltimore) ; 98(41): e17493, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31593114

RESUMO

The aim of this study was to assess the bedside brain function monitoring of color density spectral array (CDSA) for early prognostic evaluation of coma patients in pediatric intensive care unit (PICU).Forty-two consecutive pediatric coma patients were enrolled. The individual conscious state was evaluated according to the Glasgow coma scale (GCS). CDSA parameters including CDSA pattern (CDSAP), sleep-wake cycle (SWC), sleep stage (SS), and drug-induced fast wave activity (DIFWA) were recorded. Three months later, prognosis was evaluated according to pediatric cerebral performance category (PCPC) score, based on which the patients were divided into FP-group (favorable prognosis) and PP-group (poor prognosis).The changeable type of CDSAP, appearance of SWC, SS, and DIFWA were significantly correlated with favorable prognosis. Both GCS and SWC were significantly correlated with the prognosis. However, there was substantial overlap in GCS between FP-group and PP-group. Although the absence of SWC was statistically an independent risk factor for poor prognosis but with a high false positive rate (0.143), a linear logistic regression showed the odds ratio of GCS for predicting prognosis was 0.93 (95% confidence interval: 0.48-1.80; P = .83) and that of SWC was 0.12 (95% confidence interval: 0.03-0.47; P = .03). Furthermore, the absence of SWC was correlated with poor prognosis in nonintracranial infection patients.Our study found that several CDSA factors are associated with prognosis of coma patients in PICU. SWC may be a potential indicator for evaluating the prognosis of coma patients in PICU.


Assuntos
Coma/diagnóstico , Monitores de Consciência/estatística & dados numéricos , Unidades de Terapia Intensiva Pediátrica/estatística & dados numéricos , Testes Imediatos , Adolescente , Criança , Pré-Escolar , Colorimetria/métodos , Colorimetria/estatística & dados numéricos , Feminino , Escala de Coma de Glasgow , Humanos , Lactente , Modelos Logísticos , Masculino , Valor Preditivo dos Testes , Prognóstico
2.
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
3.
Chem Commun (Camb) ; 55(80): 12008-12011, 2019 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-31532419

RESUMO

Mussel-inspired enhancement of Fe3O4 catalysis was discovered towards a highly selective and sensitive colorimetric strategy for the magnetic separation-based evaluation of dopamine and/or levodopa in urine, in which the specific interaction of bis-catechol-containing analytes and mesoporous Fe3O4 NPs would form highly stable complexes of bis-catechol-Fe coordination.


Assuntos
Dopamina/urina , Levodopa/urina , Nanopartículas de Magnetita/química , Catálise , Catecóis/química , Colorimetria/métodos , Complexos de Coordenação/química , Dopamina/isolamento & purificação , Levodopa/isolamento & purificação , Oxirredução , Porosidade
5.
J Agric Food Chem ; 67(34): 9658-9666, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31381330

RESUMO

The biomimetic enzyme-linked immunosorbent assay (BELISA) is widely used for detection of small-molecule compounds as a result of low cost and reagent stability of molecularly imprinted polymers (MIPs). However, enzyme labels used in BELISA still suffer some drawbacks, such as high production cost and limited stability. To overcome the drawbacks, a biomimetic nanozyme-linked immunosorbent assay (BNLISA) based on MIPs and nanozyme labels was first proposed. For nanozyme labels, platinum nanoparticles (PtNPs) acted as peroxidase by catalyzing the oxidation of colorless 3,3',5,5'-tetramethylbenzidine (TMB) into an ideal surface-enhanced Raman scattering (SERS) marker. Blue TMB2+ and bovine serum albumin (BSA)-hapten showed superior selectivity when competing with targets for binding sites on MIPs, named the Pt@BSA-hapten probe. The BNLISA method was employed to detect triazophos with a limit of detection of 1 ng mL-1 via colorimetric and SERS methods. Replacing traditional enzymes with nanozymes for combination with MIPs may bring about a new prospect for other compound analyses.


Assuntos
Colorimetria/métodos , Organotiofosfatos/análise , Praguicidas/análise , Análise Espectral Raman/métodos , Triazóis/análise , Benzidinas/química , Materiais Biomiméticos/química , Colorimetria/instrumentação , Frutas/química , Ouro/química , Imunoadsorventes/química , Nanopartículas Metálicas/química , Platina/química , Pyrus/química , Sensibilidade e Especificidade , Análise Espectral Raman/instrumentação , Poluentes Químicos da Água/análise
6.
Chemistry ; 25(55): 12703-12707, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31418956

RESUMO

The combination of styryl dye properties with the acidity and strong photoacidity of the 2,2'-[(1''-hydroxy-4''-methyl-(E)-2'',6''-phenylene)]-bisquinolizinium enables the detection of DNA by distinct absorption and emission color changes and the fluorimetric detection of DNA in cells with epifluorescence and confocal fluorescence microscopy.


Assuntos
Colorimetria/métodos , DNA/química , Fluorometria/métodos , Fluorescência , Estrutura Molecular
7.
BMC Infect Dis ; 19(1): 676, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31370782

RESUMO

BACKGROUND: In addition to seasonal influenza viruses recently circulating in humans, avian influenza viruses (AIVs) of H5N1, H5N6 and H7N9 subtypes have also emerged and demonstrated human infection abilities with high mortality rates. Although influenza viral infections are usually diagnosed using viral isolation and serological/molecular analyses, the cost, accessibility, and availability of these methods may limit their utility in various settings. The objective of this study was to develop and optimized a multiplex detection system for most influenza viruses currently infecting humans. METHODS: We developed and optimized a multiplex detection system for most influenza viruses currently infecting humans including two type B (both Victoria lineages and Yamagata lineages), H1N1, H3N2, H5N1, H5N6, and H7N9 using Reverse Transcriptional Loop-mediated Isothermal Amplification (RT-LAMP) technology coupled with a one-pot colorimetric visualization system to facilitate direct determination of results without additional steps. We also evaluated this multiplex RT-LAMP for clinical use using a total of 135 clinical and spiked samples (91 influenza viruses and 44 other human infectious viruses). RESULTS: We achieved rapid detection of seasonal influenza viruses (H1N1, H3N2, and Type B) and avian influenza viruses (H5N1, H5N6, H5N8 and H7N9) within an hour. The assay could detect influenza viruses with high sensitivity (i.e., from 100 to 0.1 viral genome copies), comparable to conventional RT-PCR-based approaches which would typically take several hours and require expensive equipment. This assay was capable of specifically detecting each influenza virus (Type B, H1N1, H3N2, H5N1, H5N6, H5N8 and H7N9) without cross-reactivity with other subtypes of AIVs or other human infectious viruses. Furthermore, 91 clinical and spiked samples confirmed by qRT-PCR were also detected by this multiplex RT-LAMP with 98.9% agreement. It was more sensitive than one-step RT-PCR approach (92.3%). CONCLUSIONS: Results of this study suggest that our multiplex RT-LAMP assay may provide a rapid, sensitive, cost-effective, and reliable diagnostic method for identifying recent influenza viruses infecting humans, especially in locations without access to large platforms or sophisticated equipment.


Assuntos
Colorimetria/métodos , Vírus da Influenza A/genética , Influenza Humana/virologia , Técnicas de Amplificação de Ácido Nucleico/métodos , Reações Cruzadas , Humanos , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Vírus da Influenza A Subtipo H3N2/genética , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Virus da Influenza A Subtipo H5N1/genética , Subtipo H7N9 do Vírus da Influenza A/genética , Subtipo H7N9 do Vírus da Influenza A/isolamento & purificação , Vírus da Influenza A/isolamento & purificação , Vírus da Influenza A/patogenicidade , Transcrição Reversa
8.
Food Chem ; 298: 125034, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31261013

RESUMO

A wash-free and label-free colorimetric biosensor for the amplified detection of aflatoxin B1 (AFB1) has been constructed by the integration of an ingenious hairpin DNA probe with exonuclease III (Exo III)-assisted signal amplification. The presence of the AFB1 activates the continuous cleavage reactions by Exo III toward a hairpin probe, resulting in the autonomous accumulation of numerous free G-quadruplex sequences, which can catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by H2O2 to produce a colorimetric response. The naked-eye biosensor is ultrasensitive, enabling the visual detection of trace amounts of AFB1 as low as 1 pM without instrumentation. The sensor is robust and can work even when challenged with complex sample matrices such as peanut samples. With the advantages of simple operation, wash-free and label-free format, visible and intuitive output, and low cost, the naked-eye based colorimetric biosensor is expected to have potential applications for in-field detection of AFB1.


Assuntos
Aflatoxina B1/análise , Técnicas Biossensoriais/métodos , Colorimetria/métodos , Contaminação de Alimentos/análise , Benzidinas/química , Sondas de DNA/química , Exodesoxirribonucleases/química , Análise de Alimentos/métodos , Quadruplex G , Peróxido de Hidrogênio/química , Limite de Detecção
9.
Chem Commun (Camb) ; 55(61): 9019-9022, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31290863

RESUMO

DNA nanohydrogel assembled AuNPs were proposed as a high-throughput multidimensional sensing strategy for small molecule reductant profiling in rat brain. The equilibrium among AuNPs, DNA nanohydrogel and targets produced a unique fingerprint-like pattern for differentiating the reducing capacity.


Assuntos
Encéfalo/metabolismo , DNA de Cadeia Simples/química , Ouro/química , Hidrogéis/química , Nanopartículas Metálicas/química , Substâncias Redutoras/análise , Animais , Colorimetria/métodos , Análise Discriminante , Glutationa/líquido cefalorraquidiano , Oxirredução , Tamanho da Partícula , Ratos
10.
Int Braz J Urol ; 45(5): 916-924, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31268639

RESUMO

OBJECTIVE: This study aims to investigate the association of filamin A with the function and morphology of prostate cancer (PCa) cells, and explore the role of filamin A in the development of PCa, in order to analyze its significance in the evolvement of PCa. MATERIALS AND METHODS: A stably transfected cell line, in which filamin A expression was suppressed by RNA interference, was first established. Then, the effects of the suppression of filamin A gene expression on the biological characteristics of human PCa LNCaP cells were observed through cell morphology, in vitro cell growth curve, soft agar cloning assay, and scratch test. RESULTS: A cell line model with a low expression of filamin A was successfully constructed on the basis of LNCaP cells. The morphology of cells transfected with plasmid pSilencer-filamin A was the following: Cells were loosely arranged, had less connection with each other, had fewer tentacles, and presented a fibrous look. The growth rate of LNCap cells was faster than cells transfected with plasmid pSilencer-filamin A (P<0.05). The clones of LNCap cells in the soft agar cloning assay was significantly fewer than that of cells stably transfected with plasmid pSilencer-filamin A (P<0.05). Cells stably transfected with plasmid pSilencer-filamin A presented with a stronger healing and migration ability compared to LNCap cells (healing rate was 32.2% and 12.1%, respectively; P<0.05). CONCLUSION: The expression of the filamin A gene inhibited the malignant development of LNCap cells. Therefore, the filamin A gene may be a tumor suppressor gene.


Assuntos
Filaminas/análise , Filaminas/fisiologia , Neoplasias da Próstata/patologia , Western Blotting , Linhagem Celular Tumoral , Proliferação de Células , Células Cultivadas , Colorimetria/métodos , Filaminas/genética , Formazans , Humanos , Masculino , Plasmídeos , Neoplasias da Próstata/genética , Sais de Tetrazólio , Fatores de Tempo , Transfecção/métodos , Cicatrização/fisiologia
11.
Chemistry ; 25(51): 11940-11944, 2019 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-31317582

RESUMO

In addition to superior enzyme-mimicking abilities, nanozymes also have intrinsic physicochemical properties. Integrating the enzyme-like activities and tunable physicochemical properties into a single nanoparticle is a promising strategy for versatile nanozyme design and application. Herein, a composite nanozyme in which Au nanoparticles are encapsulated by Au nanoclusters (AuNP@AuNCs) is presented. By integrating the peroxidase-mimicking ability of fluorescent Au NCs with the glucose oxidase-like activity of Au NPs, the composite nanozyme realized cascade assay of glucose without the aid of external indicators. Compared to traditional multistep colorimetric methods, the analytical process was highly simplified by using the self-responsive nanozyme. This synthetic strategy provided valuable insights into exploring talented nanozymes for sensing diverse targets.


Assuntos
Glucose Oxidase/química , Glucose/metabolismo , Ouro/química , Nanopartículas Metálicas/química , Peroxidase/química , Colorimetria/métodos , Glucose/química , Glucose Oxidase/metabolismo
12.
Food Chem ; 300: 125177, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31323607

RESUMO

A point-of-care testing chip was developed for the colorimetric detection of inorganic mercury ion (Hg2+). The disposable chip fabricated by three-dimensional printing technology contains DNAzymes produced by rolling circle amplification (RCA); a color change caused by the enzymatic reaction between DNAzymes and the peroxidase substrate 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) is measured using a portable spectrophotometer. In the "turn-off"-type RCA reaction, the annealing of the T(12) primer that initiates the RCA reaction is blocked by the interaction of thymine with Hg2+; thus, the amount of amplified DNAzymes causing a color change is decreased depending on Hg2+ concentration. The colorimetric signal is enhanced by amplifying double-repeat DNAzymes from a circular DNA template. The chip detected Hg2+ in tap drinking water samples with high sensitivity (lowest validated value: 3.6 µg/L) and showed better selectivity, precision, and reproducibility than conventional analysis instruments. This low-cost easy-to-use platform can reduce the risk of accidental Hg2+ poisoning.


Assuntos
Colorimetria/instrumentação , Água Potável/análise , Mercúrio/análise , Impressão Tridimensional , Poluentes Químicos da Água/análise , Colorimetria/métodos , DNA Catalítico/química , Desenho de Equipamento , Mercúrio/química , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Espectrofotometria/métodos
13.
Anal Chim Acta ; 1078: 119-124, 2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31358209

RESUMO

In this work, CaF2 nanoparticles were successfully synthesized by a simple direct precipitation method and firstly used as a peroxidase mimics for rapid and high sensitive colorimetric detection of aldosterone. The CaF2 nanoparticles were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM) and powder X-ray diffraction (XRD). The CaF2 nanoparticles can oxidize 3,3',5,5'-tetramethylbenzidine (TMB) to produce a blue product oxidized TMB (oxTMB) in the presence of H2O2 and this peroxidase-like activity of CaF2 is found out to follow Michaelis-Menten kinetics. Experiments showed that the catalytic mechanism of CaF2 nanoparticles was attributed to that it could result in the decomposition of H2O2 to produce hydroxyl radicals (•OH). The absorbance change value of the reaction system was linear with the aldosterone concentration in the range of 2.0-40.0 nM, and the detection limit was 0.6 nM. Moreover, the developed method was applied to detect aldosterone in human serum samples. It provides a new platform for enzyme functional simulation and analytical sensing research.


Assuntos
Aldosterona/sangue , Materiais Biomiméticos/química , Fluoreto de Cálcio/química , Nanopartículas Metálicas/química , Benzidinas/química , Materiais Biomiméticos/síntese química , Fluoreto de Cálcio/síntese química , Catálise , Colorimetria/métodos , Humanos , Peróxido de Hidrogênio/química , Concentração de Íons de Hidrogênio , Cinética , Limite de Detecção , Modelos Químicos , Oxirredução , Peroxidase/química , Temperatura Ambiente
14.
Anal Chim Acta ; 1078: 135-141, 2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31358211

RESUMO

Hypochlorous acid (HOCl)/hypochlorite (OCl-), important reactive oxygen species, play essential roles in many physiological and pathological progresses. Accordingly, we developed a novel dicyanomethylene-4H-pyran (DCM)-based probe DCM-OCl for colorimetric and near-infrared fluorescent turn-on detection of OCl-. The probe exhibited excellent selectivity and sensitivity for OCl- over other bio-related analytes with a detection limit of 80 nM. The excellent selectivity of DCM-OCl for OCl- was ascribed to specific oxidative cleavage of the dimethylthiocarbamate (DMTC) recognition unit by OCl-. Moreover, DCM-OCl exhibited an ultrafast turn-on response (<3 s) to OCl-, potentially allowing real-time detection of OCl-. Furthermore, DCM-OCl was successfully used to image endogenous/exogenous OCl- in living cells.


Assuntos
Benzopiranos/química , Corantes Fluorescentes/química , Ácido Hipocloroso/análise , Tiocarbamatos/química , Benzopiranos/síntese química , Benzopiranos/toxicidade , Colorimetria/métodos , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/toxicidade , Células HeLa , Humanos , Limite de Detecção , Tiocarbamatos/síntese química , Tiocarbamatos/toxicidade
15.
Anal Chim Acta ; 1076: 131-137, 2019 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-31203957

RESUMO

As an important biomarker, alkaline phosphatase (ALP) is one of the most commonly assayed enzymes in clinical practice. Here a novel turn-on fluorescent nanoswitch for ALP assay was suggested. The nanoswitch was easily constructed via two high-affinity ligands between GSH and Al3+ and PPi and Al3+ based on the difference in the affinity. The primary fluorescence of as-prepared GSH capped Cu nanoclusters (NCs) turned on first upon the Al3+ addition due to the Al3+ induced aggregation induced emission (AIE) enhancement based on the high affinity of GSH and Al3+. The presence of PPi then made Al3+ desorb from the surface of GSH capped Cu NCs due to the higher affinity of PPi and Al3+. As a result, the fluorescence of the Cu NCs was quenched. ALP could hydrolyze PPi into phosphate, destroying the PPi-Al3+ complex and releasing Al3+. Thus, the Al3+ binds to GSH again and the fluorescence was restored. The nanoswitch was demonstrated to be sensitive and selective for ALP assay and was successfully used for the ALP assay in the human serum.


Assuntos
Fosfatase Alcalina/sangue , Alumínio/química , Difosfatos/química , Ensaios Enzimáticos/métodos , Nanopartículas Metálicas/química , Espectrometria de Fluorescência/métodos , Colorimetria/métodos , Cobre/química , Fluorescência , Glutationa/química , Humanos , Limite de Detecção
16.
Anal Chim Acta ; 1076: 91-99, 2019 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-31203968

RESUMO

The development of an automated miniaturized analytical system that allows for the rapid monitoring of carbamazepine (CBZ) levels in serum and wastewater is proposed. Molecular recognition of CBZ was achieved through its selective interaction with microbeads carrying anti-CBZ antibodies. The proposed method combines the advantages of the micro-bead injection spectroscopy and of the flow-based platform lab-on-valve for implementation of automatic immunosorbent renewal, rendering a new recognition surface for each sample. The sequential (or simultaneous) perfusion of CBZ and the horseradish peroxidase-labelled CBZ through the microbeads is followed by real-time on-column monitoring of substrate (3,3',5,5'-tetramethylbenzidine) oxidation by colorimetry. The evaluation of the initial oxidation rate and also the absorbance value at a fixed time point provided a linear response versus the logarithm of the CBZ concentration. Under the selected assay conditions, a single analysis was completed after only 11 min, with a quantification range between 1.0 and 50 µg L-1. Detection of CBZ levels in undiluted wastewater samples was feasible after a simple filtration step while good recoveries were attained for spiked certified human serum, analyzed without sample clean-up.


Assuntos
Carbamazepina/sangue , Colorimetria/métodos , Ensaio de Imunoadsorção Enzimática/métodos , Anticorpos Monoclonais/imunologia , Armoracia/enzimologia , Benzidinas/química , Carbamazepina/imunologia , Peroxidase do Rábano Silvestre/química , Humanos , Microesferas , Oxirredução , Sefarose/análogos & derivados , Sefarose/química , Águas Residuárias/análise
17.
Enzyme Microb Technol ; 128: 26-33, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31186107

RESUMO

Detection tubes are small devices for the colorimetric enzymatic detection of cholinesterase inhibitors such as sarin, soman, VX nerve agents and substances denoted as Novichok. These detectors contain carriers in the form of pellets with immobilized cholinesterase, substrate and detection reagent. Their advantages are portability, sensitivity and simplicity, enabling fast detection of such compounds from air and water in case of a terrorist attack or war. In general, maintaining the stability of an enzyme for a longer time is very problematic; therefore, its further enhancement is required for safety and financial reasons. In this study, the stability of our patented carriers in the form of pellets with immobilized butyrylcholinesterase containing an increasing amount of the unique sorbent Neusilin® US2 was evaluated. The samples containing Neusilin maintained the stability of the immobilized enzyme for a longer time even at higher temperature and humidity than the currently commercially used carrier without Neusilin, allowing improved detection of nerve agents.


Assuntos
Compostos de Alumínio/metabolismo , Técnicas Biossensoriais/métodos , Butirilcolinesterase/metabolismo , Inibidores da Colinesterase/análise , Colorimetria/métodos , Portadores de Fármacos/química , Estabilidade Enzimática/efeitos dos fármacos , Compostos de Magnésio/metabolismo , Silicatos/metabolismo , Butirilcolinesterase/química , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo
18.
Anal Bioanal Chem ; 411(17): 3801-3810, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31172237

RESUMO

The convenience of colorimetric sensors is useful for practical applications. In this work, we constructed a novel colorimetric sensor with magnetic separation ability that can be operated in nearly neutral conditions and achieve one-step detection of metabolites. Magnetic Cu doped Fe3O4@FeOOH magnetic nanocomposite (Cu/Fe3O4@FeOOH) with an oxygen vacancy was prepared by a one-step self-assembly hydrothermal method, and fully characterized by different methods. The oxygen vacancy generated by the incorporation of Cu2+ cations into the Fe3O4@FeOOH structure was confirmed to be a vital reactive site for enhancing the catalytic activity, which opens up a new way of designing highly efficient enzyme mimics. Benefiting from its inherent horseradish-peroxidase-like activity, a simple and selective enzyme-based colorimetric sensor was developed for one-step detection of H2O2 and cholesterol, and 3,3',5,5'-tetramethylbenzidine was catalyzed by H2O2 to generate a colored product of oxidized 3,3',5,5'-tetramethylbenzidine for signaling. H2O2 and cholesterol can be linearly detected in the same range from 0.01 to 0.4 mmol L-1 with detection limits of 0.0075 mmol L-1 and 0.0082 mmol L-1, respectively. The proposed colorimetric sensor has satisfactory reusability, accuracy, and practicability in human serum samples, indicating its potential application for the detection of different metabolites in the fields of life science and analytical science. Graphical abstract.


Assuntos
Técnicas Biossensoriais/métodos , Colorimetria/métodos , Cobre/química , Óxido Ferroso-Férrico/química , Peroxidase do Rábano Silvestre/química , Concentração de Íons de Hidrogênio , Magnetismo , Nanopartículas Metálicas/química , Benzidinas/química , Colesterol/sangue , Espectroscopia de Ressonância de Spin Eletrônica , Peróxido de Hidrogênio/análise , Microscopia Eletrônica de Transmissão , Oxirredução , Espectroscopia Fotoeletrônica , Reprodutibilidade dos Testes , Análise Espectral Raman , Difração de Raios X
19.
Chem Commun (Camb) ; 55(50): 7211-7214, 2019 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-31165808

RESUMO

A label-free and universal photosensitization colorimetric assay based on target-induced dsDNA termini switching has been developed for the analysis of nucleic acids, proteins, small molecules and metal ions. This strategy is highly sensitive and versatile, the principle of which will be desirable for various biosensor developments and applications.


Assuntos
Colorimetria/métodos , DNA/química , Metais/química , Ácidos Nucleicos/química , Proteínas/química , Bioensaio/métodos , Conformação de Ácido Nucleico , Conformação Proteica
20.
Analyst ; 144(11): 3613-3619, 2019 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-31070614

RESUMO

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by chronic joint inflammation and one of the main causes of chronic disability worldwide with high prevalence in the ageing population. RA is characterized by autoantibody production, synovial inflammation and bone destruction, and the most accepted biomarker is rheumatoid factor (RF) autoantibodies. In this work, we developed a low-cost approach for the detection and quantification of the RF marker. This colorimetric immunosensor is based on gold nanoprobe crosslinking that results in extensive aggregation in the presence of the pentameric IgM RF. Aggregation of the nanoconjugates yields a color change from red to purple that can be easily observed by the naked eye. The interaction between nanoconjugates and the specific target was confirmed via dynamic light scattering (DLS), Raman spectroscopy and atomic force microscopy (AFM) imaging. This conceptual system shows a LOD of 4.15 UA mL-1 IgM RF (clinical threshold is set for 20 IU mL-1). The one-step biosensor strategy herein proposed is much faster than conventional detection techniques, without the need for secondary antibodies, additional complex washing or signal amplification protocols. To the best of our knowledge this is the first report on target induced aggregation of gold nanoprobes for quantitative colorimetric autoantibody detection.


Assuntos
Artrite Reumatoide/diagnóstico , Ouro/química , Imunoglobulina M/sangue , Nanopartículas Metálicas/química , Fator Reumatoide/sangue , Artrite Reumatoide/imunologia , Biomarcadores , Técnicas Biossensoriais/métodos , Colorimetria/métodos , Humanos , Fragmentos Fc das Imunoglobulinas/imunologia , Imunoglobulina G/imunologia , Imunoglobulina M/imunologia , Limite de Detecção , Tamanho da Partícula , Fator Reumatoide/imunologia
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