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1.
Medicina (B Aires) ; 79(4): 271-275, 2019.
Artigo em Espanhol | MEDLINE | ID: mdl-31487246

RESUMO

There is much controversy about the benefits of the use of serum calcitonin (CT) in the initial evaluation of patients with thyroid nodules. The objective of the study was to early identify medullary thyroid carcinoma (MTC) through the routine measurement of CT in thyroid nodular pathology in a large cohort of patients from Buenos Aires, Argentina. Consecutive patients with nodular thyroid disease (n=1017) were studied. CT was measured by chemiluminescence, normal value: up to 18 pg/ml in men and 12 pg/ml in women. In two patients, hypercalcitoninemia was confirmed in repeated measurements. Fine needle aspiration with CT measurement in the needle wash fluid identified MTC in nodules with citology abnormalities. The genetic study was positive in one patient (mutation exon 14, Val804Met, MTC familiar). The other presented a polymorphism (exon 13 L769L heterozygous - exon 15 S904S heterozygous). In both cases, CT was normalized 3 months after surgery and remained normal after 6 years of follow-up. The routine measurement of CT in thyroid nodular pathology was useful to detect two cases of MTC, one of them sporadic and the other familiar in this cohort. The prevalence of MTC was 0.2%.


Assuntos
Calcitonina/sangue , Carcinoma Neuroendócrino/diagnóstico , Neoplasias da Glândula Tireoide/diagnóstico , Nódulo da Glândula Tireoide/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Biópsia por Agulha Fina , Carcinoma Neuroendócrino/sangue , Carcinoma Neuroendócrino/patologia , Estudos de Coortes , Diagnóstico Precoce , Feminino , Humanos , Imuno-Histoquímica , Luminescência , Masculino , Pessoa de Meia-Idade , Sensibilidade e Especificidade , Neoplasias da Glândula Tireoide/sangue , Neoplasias da Glândula Tireoide/patologia , Nódulo da Glândula Tireoide/sangue , Adulto Jovem
2.
Rev Bras Parasitol Vet ; 28(3): 518-521, 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31482939

RESUMO

The objective of this study was to report an outbreak of human toxoplasmosis at a research institution in Londrina, Paraná, from December 2015 to February 2016. Blood samples from 26 symptomatic individuals were collected and the microparticle chemiluminescence immunoassay was performed to detect IgM, IgG and specific IgG avidity test in the official laboratory. A total of 20 people with symptoms and serology compatible with acute toxoplasmosis (IgM positive and IgG with low avidity) were selected as cases, while 45 asymptomatic employees working in the same teams and during the same shifts were selected as controls. All the participants of the investigation answered an epidemiological questionnaire. Three samples of water and one sludge from the institution's supply cisterns, 10 soil samples, 11 plant samples, three cat fecal samples and one domestic feline cadaver were collected for analysis of the polymerase chain reaction (PCR) for T. gondii. After analyzing the epidemiological data, the consumption of vegetables in the restaurant of the institution was the only variable associated with the occurrence of the disease. In laboratory results, all the samples showed negative results to PCR. The rapid recognition of the outbreak, early notification and investigation could have broken the chain of transmission early, thus preventing the emergence of new cases. In addition, the adoption of good food handling practices could have prevented the occurrence of the outbreak.


Assuntos
Anticorpos Antiprotozoários/sangue , Surtos de Doenças , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Toxoplasma/imunologia , Toxoplasmose/epidemiologia , Adulto , Idoso , Animais , Brasil/epidemiologia , Estudos de Casos e Controles , Gatos , Feminino , Humanos , Imunoensaio , Luminescência , Masculino , Pessoa de Meia-Idade , Fatores de Risco
3.
Inorg Chem ; 58(16): 10611-10615, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31380629

RESUMO

Luminescent lanthanides provide a promising alternative to organic chromophores for cellular bioimaging and bioassay applications; efficacy is closely governed by their respective quantum yields. Conventionally utilized quantum-yield measurements for lanthanides are laborious and not amenable to rapid relative comparison of compound performance. Here, we introduce a high-throughput optical imaging method to determine and directly compare relative quantum yield using Cherenkov-radiation-mediated excitation of luminescent lanthanide complexes.


Assuntos
Complexos de Coordenação/química , Ensaios de Triagem em Larga Escala , Elementos da Série dos Lantanídeos/química , Teoria Quântica , Luminescência , Conformação Molecular
4.
Chem Commun (Camb) ; 55(72): 10768-10771, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31432821

RESUMO

By covalent combination of a chiral amino acid, lipid, and achiral phenothiazine derivative, a reaction-based chiroptical probe, PTZ-D, was obtained. PTZ-D could self-assemble into a chiral organogel realizing the chirality transformation from a chiral amino acid to a self-assembled system and displaying unprecedented chiroptical monitoring of ClO- with switchable CPL signals.


Assuntos
Aminoácidos/química , Ácido Hipocloroso/análise , Luminescência , Imagem Óptica , Géis/síntese química , Géis/química , Estrutura Molecular , Tamanho da Partícula
5.
J Agric Food Chem ; 67(32): 9022-9031, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31339724

RESUMO

The quantitative multiplex immunochromatographic assay (mICA) has received an increasing amount of attention in multitarget detection. However, the quantitative results in the reported mICAs were obtained by recording the signals on the test lines that with which various analyte-independent factors readily interfere, resulting in inaccurate quantitation. The ratiometric strategy using the T/C value (ratios of signals on the test line to those of the control line) for signal correction can effectively circumvent these issues to enable more accurate detection. Herein, we present for the first time a novel ratiometric mICA strip with multiple T lines for the simultaneous quantitative detection of aflatoxin B1 (AFB1), fumonisin B1 (FB1), and ochratoxin A (OTA) using highly luminescent quantum dot nanobeads (QBs) as enhanced signal reporters. To achieve reliable ratiometric signal output, a biotin-streptavidin system was introduced to replace the conventional anti-mouse IgG antibody for reliable reference signals on the control line that are completely independent of the signal probe and analyte. By using stable T/C values as quantitative signals, our proposed QB-mICA method can successfully detect three mycotoxins with concentrations as low as 1.65 pg/mL for AFB1, 1.58 ng/mL for FB1, and 0.059 ng/mL for OTA. The detection performance of the developed QB-mICA strip, including precision, specificity, and reliability, was further evaluated using artificially contaminated cereal samples. The results demonstrate the improved accuracy and reliability of quantitative determination by comparison with the anti-mouse IgG antibody. Thus, this work provides a promising strategy for developing a ratiometric mICA method for accurately quantifying multiple analytes using the biotin-SA system, opening up a new direction in quantitative mICAs.


Assuntos
Aflatoxina B1/análise , Fumonisinas/análise , Imunoensaio/métodos , Ocratoxinas/análise , Animais , Biotina/química , Grão Comestível/química , Contaminação de Alimentos/análise , Imunoensaio/instrumentação , Luminescência , Camundongos , Micotoxinas , Pontos Quânticos , Estreptavidina/química
6.
Bioresour Technol ; 291: 121801, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31326685

RESUMO

Achieving high biomass productivity is critical for establishing a successful large-scale algal facility. Microalgae cultures in raceway ponds are normally light limited. To achieve high biomass productivity, there is a need to develop a system to deliver light into the depth of microalgal cultures in raceway ponds. We investigated red and blue luminescent solar concentrators (LSCs) in outdoor raceway ponds to downgrade the sunlight, re-emit and, deliver it into the depth of Arthrospira platensis culture operated at 21 cm depth. When red LSCs were used, the biomass productivity (12.2 g m-2 d-1) and phycocyanin productivity (8.5 mg L-1 d-1) of A. platensis increased 26% and 44%, respectively. However, using blue LSCs resulted in no significant increase in A. platensis biomass productivity. Therefore, for generating same phycocyanin productivity using red LSCs, 44% less cultivation area would be required. This can lead to a significant reduction in the cost of phycocyanin production.


Assuntos
Biomassa , Ficocianina/biossíntese , Tanques/microbiologia , Spirulina/metabolismo , Cor , Luminescência , Microalgas/metabolismo , Luz Solar
7.
Anal Bioanal Chem ; 411(17): 3789-3800, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31161320

RESUMO

MicroRNAs (miRNAs) in a blood sample are usually measured by quantitative reverse transcription PCR (qRT-PCR), microarray, and next-generation sequencing (NGS) which requires time-consuming pre-treatment, manual operation, and a stand-alone instrument. To overcome these disadvantages, miRNA testing has been developed using the automated analyzers routinely used in clinical laboratories. An isothermal DNA amplification reaction was adapted to a fully automated immunoassay analyzer that conducts extraction, amplification, and detection processes at 37 °C in 44 min. In a reaction vessel, a pre-designed single-stranded signal DNA was amplified in the presence of miRNA, using DNA templates, DNA polymerase, and nicking endonuclease. Then, the amplified signal DNA was hybridized by one DNA probe attached to a magnetic particle and another DNA probe labeled with acridinium ester. After the chemiluminescence reaction, luminescence intensity was automatically measured. The automated assays of cancer-related miRNAs were implemented on the analyzer with throughput of 66 tests per hour. In the assays with one-step amplification, three miRNAs (miR-21-5p, miR-18a-5p, and miR-500a-3p) at concentrations lower than 100 fM were automatically detected and the cross reactivity for miR-21-5p with fifteen similar miRNAs was not higher than 0.02%. In the assay with two-step amplification, detection sensitivity and amplification rate for miR-21-5p were 3 fM and 103-fold, respectively. The coefficient of variations (CVs) in the measurement at the target concentrations from 5 fM to 1000 pM were less than 8%. Furthermore, we also achieved automated nucleic acid detection in human serum. The proposed fully automated miRNA assays showed high sensitivity, low cross reactivity, and reproducibility suitable for clinical use. Graphical abstract.


Assuntos
Imunoensaio/métodos , MicroRNAs/análise , Técnicas de Amplificação de Ácido Nucleico/métodos , Automação , Humanos , Luminescência
8.
Anal Bioanal Chem ; 411(20): 5175-5186, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31187200

RESUMO

An ultrasensitive electrochemiluminescence (ECL) immunosensor for alpha-fetoprotein (AFP) detection based on a poly(aniline-luminol)/graphene oxide nanocomposite was developed. The nanocomposite, which was prepared using a fast and simple chemical oxidation strategy for the first time, showed excellent ECL performance. This outstanding ECL performance is due to the formation of poly(aniline-luminol) on the graphene oxide (GO) surface and the excellent electron-transfer properties of GO. Moreover, the poly(aniline-luminol)/graphene oxide nanocomposite has abundant amino groups at its surface, making it a good platform for biomacromolecule labeling. Using the nanocomposite, a novel ECL immunosensor for the determination of AFP was successfully developed. Anti-AFP was immobilized on the surface of a poly(aniline-luminol)/graphene oxide nanocomposite-modified electrode using a glutaraldehyde crosslinking method to form the ECL immunosensor. The AFP was then captured at the modified electrode surface through an antigen-antibody immunoreaction. When the AFP was captured by its antibody, the ECL intensity decreased. This ECL immunosensor for the detection of AFP exhibited a linear range of 1.7 × 10-12 to 1.7 × 10-8 mg mL-1 and a detection limit of 5 × 10-13 mg mL-1, indicating high sensitivity and linearity across a wide concentration range. Furthermore, the immunosensor was successfully applied to determine AFP in a real-world human serum sample. Graphical abstract A new poly(aniline-luminol)/graphene oxide nanocomposite was prepared using a fast and simple strategy for the first time, and an ultrasensitive electrochemiluminescence (ECL) immunosensor for alpha-fetoprotein (AFP) detection based on this nanocomposite was developed.


Assuntos
Compostos de Anilina/química , Técnicas Biossensoriais , Técnicas Eletroquímicas/métodos , Grafite/química , Luminescência , Luminol/química , Nanocompostos/química , alfa-Fetoproteínas/análise , Humanos , Limite de Detecção , Microscopia Eletrônica de Transmissão , Reprodutibilidade dos Testes , Soro , Espectrofotometria Ultravioleta , Análise Espectral Raman , alfa-Fetoproteínas/imunologia
9.
Talanta ; 202: 452-459, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31171207

RESUMO

Despite the success in long-term storage of food and dietary products using antibiotics as supplements, enormous levels of their residues have remained as a significant health concern, leading to severe toxicity issues on consumption. Herein, we report an ultrasensitive and highly selective aptasensor based on carbon nanoparticles (CNPs) through a fluorescence-based aptamer-linked immunosorbent assay (FALIA) for rapid detection of kanamycin (KAA) residue. The fabricated CNP-aptasensor exhibited superior selectivity with exceptional photoluminescence properties. Under the optimal conditions, the linear equation of standard KAA solution was Y = -0.2279LogX+1.3648 (R = -0.9893) ranged from 10-4 to 10-7 ppb with excellent relative standard deviations (RSD) between 3.12 and 5.59 % (n = 3). Moreover, the limit of detection (LOD) was lower than 5.0 × 10-8 ppb. Together, the excellent recovery and significant efficacy in the rapid detection of antibiotics at a low level in milk indicate that this fabricated CNP-aptasensor has a great potential in the establishment of an efficient antibiotic detector system in food and other nutraceutical industries.


Assuntos
Aptâmeros de Nucleotídeos/química , Carbono/química , Técnicas de Imunoadsorção , Canamicina/análise , Luminescência , Pontos Quânticos/química
10.
Nat Methods ; 16(7): 577, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31249415
11.
Chem Commun (Camb) ; 55(50): 7259-7262, 2019 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-31168526

RESUMO

A fluorine-18 doped bismuth upconversion luminescence (UCL) nanoprobe (18F-UNBOF) was quickly synthesized within 1 min at room temperature. 18F-UNBOF showed strong X-ray attenuation characteristics, stable radioactive 18F-labeling abilities and UCL properties. 18F-UNBOF nanoparticles could be utilized for tri-modal CT/PET/UCL imaging in vivo.


Assuntos
Bismuto/química , Radioisótopos de Flúor/química , Nanoestruturas/química , Meios de Contraste , Luminescência , Microscopia Eletrônica de Transmissão , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons
12.
Ecotoxicol Environ Saf ; 181: 187-193, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31195227

RESUMO

Microbial polysaccharides, due to their unique physiochemical properties, have found application in the food industry, cosmetics, pharmacy and medicine. In the environment, microbes can use polysaccharides to alleviate the adverse effects of heavy metals in their close proximity. This adaptive property shows interesting potential for bioremediation. Herein, the effects of the exopolysaccharides (EPS) levan, produced by the bacterium Bacillus licheniformis NS032 and pullulan, produced by the fungus Aureobasidium pullulans CH-1 in the presence of copper (Cu2+) have been investigated for the first time on antioxidant enzyme activity, respiration and Cu2+ bioaccumulation of Daphnia magna as well as the bioluminescence of Vibrio fischeri. Both EPS decreased toxicity of Cu2+ in the acute test with D. magna. The activity of catalase (CAT) was significantly diminished after acute exposure to Cu2+ in comparison to treatments with Cu2+ and EPS, while in the prolonged acute exposure the CAT activity did not show statistically significant (P ≤ 0.05) differences between treatments with and without the EPS. According to ICP-MS results, during prolonged acute exposure of neonates, the bioaccumulation of Cu2+ in treatments without the EPS was 52.03 µg/g of biomass (wet), while in treatments with EPS, the bioaccumulation was lower by one order of magnitude. The respiration of neonates during acute exposure to Cu2+ with or without the EPS was monitored using the MicroOxymax respirometer, and the results show the EPS can positively effect the respiration. In the case of bacterial bioluminescence, the toxicity of Cu2+ decreased in treatments with EPS (30 min EC10) from 3.54 mg/L to 140.61 mg/L (levan) and 45.00 mg/L (pullulan). This study demonstrates protective effect of EPS against Cu2+ toxicity on D. magna and V. fischeri, and opens the door for further investigation of potential application of levan and pullulan in bioremediation of heavy metals and mitigation of their adverse effects in the aquatic environment.


Assuntos
Cobre/toxicidade , Frutanos/farmacologia , Glucanos/farmacologia , Poluentes Químicos da Água/toxicidade , Aliivibrio fischeri/química , Aliivibrio fischeri/efeitos dos fármacos , Animais , Ascomicetos/metabolismo , Bacillus licheniformis/metabolismo , Catalase/metabolismo , Cobre/farmacocinética , Daphnia/efeitos dos fármacos , Daphnia/enzimologia , Daphnia/crescimento & desenvolvimento , Daphnia/metabolismo , Luminescência , Substâncias Protetoras/farmacologia , Poluentes Químicos da Água/farmacocinética
13.
J Biomed Nanotechnol ; 15(8): 1792-1800, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31219017

RESUMO

Since the discovery of exosomes, their potential diagnostic value has been the focus of considerable research. However, the lack of a rapid and simple technique for the quantitative analysis of exosomes greatly limits the application of exosomes in clinical research. In this study, we describe a newly developed one-step chemiluminescence immunoassay for the rapid quantitative analysis of exosomes from biofluids. Our new technique, named ExoNANO, adopts a double-antibody sandwich strategy using anti-CD63 antibody-conjugated superparamagnetic iron oxide particles (SIOPs) and acridinium ester (ACE)-labeled anti-CD9 antibodies. SIOPs have narrow size distribution and high magnetic susceptibility, and ACE has excellent chemiluminescent properties such as low background signal and no need for a catalyst. We demonstrated that ExoNANO allows the quantitative analysis of exosomes in the range of 2.92 ×105 to 2.80×108 particles/µL, with a limit of detection of 2.63×105 particles/µL. Using ExoNANO, we quantified exosomes in cell culture medium and clinical biofluids such as serum, saliva, ascitic fluid, and cerebrospinal fluid. We believe that ExoNANO might pave the way for the rapid isolation and quantitative analysis of exosomes for routine clinical applications.


Assuntos
Exossomos , Nanopartículas de Magnetita , Compostos Férricos , Imunoensaio , Luminescência
14.
J Biomed Nanotechnol ; 15(8): 1832-1838, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31219023

RESUMO

Hepatitis B virus (HBV) has been always threatening to health. It is significant to establish an effective strategy for HBV carriers and hepatitis B patients diagnosis at early stage of infection in clinic. Herein, we combined nested PCR, chemiluminescence assay and magnetic separation technology to establish a highly sensitive and stable strategy for low-abundance HBV-DNA detection. Six types of monodisperse Fe3O4 magnetic beads (MBs) were fabricated and coated with SiO2 layer (MBs@SiO2). The effect of MBs@SiO2 size on HBV-DNA extraction and chemiluminescence assay was explored, and results displayed that the MBs@SiO2-F particles with largest size were much more suitable for HBV-DNA extraction than others, and MBs@SiO2-C with the size range between 330 nm-450 nm performed best in chemiluminescence assay. As one of key factors, the concentration (or density) of the probe fixed on MBs@SiO2 surface was optimized for chemiluminescence assay, exhibiting the best assay result when reaction system contained 2.0 µM of probe. Finally, under the best reaction conditions, low-abundance HBV serum specimens were sensitively and stably detected, and the result of HBV specimen with 34 copy/mL loads showed significant difference with negative and blank (p < 0.001).


Assuntos
Vírus da Hepatite B , Hepatite B , DNA Viral , Humanos , Luminescência , Reação em Cadeia da Polimerase , Dióxido de Silício
15.
Inorg Chem ; 58(14): 9351-9357, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31246450

RESUMO

We designed and synthesized NaYF4:Yb,Tm@LiLuF4:Nd core-shell nanoparticles, which can emit at ∼800 nm under 980 nm excitation and at ∼1060 nm under 808 nm excitation, simultaneously having an upconversion and downshifting mechanism for near-infrared (NIR) emission. After surface modification with sodium citrate, the soluble nanoparticles were used in the in vitro NIR luminescence imaging to compare the penetration depth and the scattering of tissue. Furthermore, to determine the differences between the upconversion and downshifting fluorescence for biological imaging, the soluble nanoparticles also were operated on the aforementioned two modes for in vivo imaging.


Assuntos
Diagnóstico por Imagem/métodos , Elementos da Série dos Lantanídeos/química , Nanopartículas Metálicas/química , Animais , Luminescência , Camundongos , Espectroscopia de Luz Próxima ao Infravermelho
16.
Food Chem ; 297: 124959, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253273

RESUMO

Volatile sulfur-containing compounds (VSCs) often exist at extremely low concentrations, making them difficult to be determined. The VSCs in Laobaigan (LBG) Baijiu were analyzed by headspace solid-phase microextraction (HS-SPME) coupled with GC × GC-SCD, by which 12 VSCs were identified. Among the 65 odor-active compounds that were determined by GC-O with the aid of aroma extract dilution analysis (AEDA), benzenemethanethiol and 2-methyl-3-furanthiol were found to possess the highest FD values of 6561. The limits of detection (LODs) of the identified VSCs determined by GC × GC-SCD were found to be extremely low at 0.05-1.53 ng/L, with their analytical recoveries from 85% to 116%. The VSCs in the LBG samples were determined in a range of concentrations from 0.77 ±â€¯0.02 µg/L to 60.04 ±â€¯2.32 µg/L. Benzenemethanethiol, dimethyl trisulfide, 2-methyl-3-furanthiol and 2-furfurylthiol exhibited odor activity values (OAVs) > 100 and significantly contributed to the overall aroma of LBG Baijiu.


Assuntos
Bebidas Alcoólicas/análise , Análise de Alimentos/métodos , Odorantes/análise , Enxofre/análise , Compostos Orgânicos Voláteis/análise , Cromatografia Gasosa/métodos , Furanos/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Limite de Detecção , Luminescência , Olfatometria/métodos , Microextração em Fase Sólida/métodos , Compostos de Sulfidrila/análise , Compostos de Enxofre/análise , Compostos Orgânicos Voláteis/química
17.
Talanta ; 201: 52-57, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31122460

RESUMO

More and more attention about food safety leads to a research hotspot to develop new detection methods for food contaminant. To address the problems of serious interference and low sensitivity, a chemiluminescent aptasensor for the detection of aflatoxin B1(AFB1) in food was developed in this paper. It is based on horseradish peroxidase (HRP) catalyze the luminol chemiluminescence reaction. The hybridization chain reaction (HCR) signal amplification strategy has been used to improve the detection sensitivity. Magnetic separation could further reduce background signal obviously at the same time. AFB1 as a model of analyte to test the capability of our developed assay system. Under the optimal experimental conditions, CL intensity showed a good linear correlation with the concentrations of AFB1 ranging from 0.5 to 40 ng mL-1. The limit of detection was estimated 0.2 ng mL-1 based on 3 times of the signal-to-noise ratio which is lower than those of the previously reported sensors. It could be used to detect AFB1 content in real samples, such as peanuts and milk which were purchased in local supermarket. The results proved that the sensing system has good anti-interference and selectivity. In all, it has potential for practical application in food safety field.


Assuntos
Aflatoxina B1/análise , Aptâmeros de Nucleotídeos/química , Arachis/química , Técnicas Biossensoriais/métodos , Contaminação de Alimentos/análise , Leite/química , Animais , Aptâmeros de Nucleotídeos/genética , Armoracia/enzimologia , DNA/química , DNA/genética , Peroxidase do Rábano Silvestre/química , Peróxido de Hidrogênio/química , Limite de Detecção , Luminescência , Medições Luminescentes , Luminol/química , Hibridização de Ácido Nucleico , Oxirredução
18.
Talanta ; 200: 57-66, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31036225

RESUMO

In our work, aptamers and hemin/G-quadruplex DNAzyme modified sandwich-rod graphene quantum dots @ graphene oxide @ carbon fiber composite (DNAzyme/L-Apt/GQDs@GO@CF) was successfully prepared for sensitive and selective chemiluminescence (CL) detection of lysozyme (LZM). Initially, GQDs@GO@CF was successfully prepared and characterized. Lysozyme aptamers (L-Apt) as a recognition element and hemin/G-quadruplex DNAzyme (DNAzyme) as a catalyst of luminal - H2O2 were modified on the surface of GQDs@GO@CF, sequentially. The immobilization properties of GQDs@GO@CF to L-Apt and the adsorption properties of L-Apt/GQDs@GO@CF to DNAzyme were also researched, respectively. Then, the modified sandwich-rod carbon fiber composite was applied to the construction of CL biosensor for LZM detection. When LZM existed, DNAzyme would be released from the surface of L-Apt/GQDs@GO@CF and catalyzed the reaction of luminal - H2O2. Under optimized conditions, the CL biosensor for LZM detection showed wide linear range of 2.64 × 10-10 to 6.6 × 10-8 g/L and low detection limit of 1.25 × 10-11 g/L (3δ). Finally, the CL biosensor was successfully used for LZM detection in human urine samples and illustrated the potential application in pratical samples.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais , Carbono/química , DNA Catalítico/química , Hemina/química , Muramidase/análise , Adsorção , DNA Catalítico/metabolismo , Quadruplex G , Luminescência , Muramidase/metabolismo , Propriedades de Superfície
19.
Nat Commun ; 10(1): 2064, 2019 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-31048701

RESUMO

Afterglow imaging with long-lasting luminescence after cessation of light excitation provides opportunities for ultrasensitive molecular imaging; however, the lack of biologically compatible afterglow agents has impeded exploitation in clinical settings. This study presents a generic approach to transforming ordinary optical agents (including fluorescent polymers, dyes, and inorganic semiconductors) into afterglow luminescent nanoparticles (ALNPs). This approach integrates a cascade photoreaction into a single-particle entity, enabling ALNPs to chemically store photoenergy and spontaneously decay it in an energy-relay process. Not only can the afterglow profiles of ALNPs be finetuned to afford emission from visible to near-infrared (NIR) region, but also their intensities can be predicted by a mathematical model. The representative NIR ALNPs permit rapid detection of tumors in living mice with a signal-to-background ratio that is more than three orders of magnitude higher than that of NIR fluorescence. The biodegradability of the ALNPs further heightens their potential for ultrasensitive in vivo imaging.


Assuntos
Engenharia Química/métodos , Microscopia Intravital/métodos , Imagem Molecular/métodos , Nanopartículas/química , Neoplasias/diagnóstico por imagem , Animais , Linhagem Celular Tumoral/transplante , Estudos de Viabilidade , Feminino , Corantes Fluorescentes/química , Luminescência , Camundongos , Camundongos Nus , Microscopia de Fluorescência/métodos , Nanotecnologia/métodos , Sensibilidade e Especificidade
20.
Anal Bioanal Chem ; 411(18): 4203-4211, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31062061

RESUMO

A homogeneous electrogenerated chemiluminescence (ECL) immunoassay for highly sensitive quantification of specific biomarkers based on immunomagnetic beads and homogeneous detection on a magnetic electrode was developed, for the first time. The magnetic electrode is made of a glassy carbon electrode and a series of ring permanent magnets. D-Dimer antigen was taken as a model analyte while biotinylated D-dimer antibody bound on the streptavidin-coated magnetic beads was utilized as a magnetic capture probe and ruthenium complex-labeled D-dimer antibody was employed as an ECL probe. After a fixed amount of magnetic capture probe and the ECL probe was introduced into analyte D-dimer solution, the "sandwich" immunoconjugates on the magnetic beads were formed in tested solution and then magnetically concentrated on the surface of the magnetic electrode. The homogeneous ECL immunoassay for quantification of specific biomarker was directly carried out in the presence of co-reactant tripropylamine. The low detection limit of 1 ng/mL in magnetic enrich time of 2 min and the good magnetic regeneration for the detection of D-dimer were achieved. The magnetic bead shield ECL emission was extensively discussed. This work demonstrates that the homogeneous (separation-free) ECL immunoassay using magnetic beads and magnetic electrode is a promising approach to quantify the biomarkers with high sensitivity and selectivity and in a short time. This approach can be easily extended to ECL and electrochemical biosensing for other biomarkers. Graphical abstract.


Assuntos
Biomarcadores/análise , Eletrodos , Imunoensaio/métodos , Luminescência , Magnetismo , Técnicas Biossensoriais , Limite de Detecção
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