Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Mais filtros

Base de dados
Intervalo de ano de publicação
Nanoscale ; 13(29): 12546-12552, 2021 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-34477613


A metal-organic framework (MOF) material was prepared from 2-aminoterephthalic acid and aluminum chloride with a solvothermal synthesis protocol. The as-prepared MOF material named NH2-MIL-53(Al) emitted a very intensive fluorescent (FL) signal after it was hydrolyzed in alkaline solution for releasing numerous FL ligands NH2-H2BDC. Thus it can be considered as a sensitive FL probe for studying biorecognition events. In this proof-of-principle work, a double-site recognition method was established to quantify Staphylococcus aureus (S. aureus) relying on the alkaline hydrolysis property of the MOF material. In particular, magnetic beads (MBs) modified with pig IgG were adopted for binding S. aureus based on the strong affinity between pig IgG and protein A on the bacterial surface. Meanwhile, MOF NH2-MIL-53(Al)-tagged teicoplanin (TEI) was adopted for tracing the target bacteria. By hydrolyzing the MOF material bound on the MBs to trigger the FL signal, S. aureus can be quantified with a dynamic range of 3.3 × 103-3.3 × 107 CFU mL-1 and a detection limit of 5.3 × 102 CFU mL-1 (3σ). The method can exclude efficiently the interference from other common bacteria. It has been applied to quantify S. aureus in saliva, pomegranate green tea, glucose injection and milk samples with satisfactory results, verifying the application potential for analyzing various types of real samples contaminated with S. aureus.

Estruturas Metalorgânicas , Infecções Estafilocócicas , Animais , Corantes Fluorescentes , Hidrólise , Infecções Estafilocócicas/diagnóstico , Staphylococcus aureus , Suínos
Anal Chim Acta ; 1180: 338855, 2021 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-34538321


As one of the top three opportunistic pathogens, Pseudomonas aeruginosa (P. aeruginosa) has long accounted for hospital-acquired infections with high risk of death. In this work, a fluorescent method based on a dual-site recognition mode was developed for rapid assay of P. aeruginosa. Employing its strong binding capability towards lipid A on the outer membrane of Gram-negative bacteria, polymyxin B acted as one recognition element for P. aeruginosa. To overcome the poor binding specificity of polymyxin B, a recombinant bacteriophage tail fiber protein was expressed and employed as a species-specific recognition element for the target pathogen. Thus a dual-site recognition mode was developed for specific assay of P. aeruginosa species by using fluorescein isothiocyanate as a fluorescent probe. The target pathogen can be assayed within a broad dynamic range from 2.0 × 103 CFU mL-1 to 2.0 × 107 CFU mL-1. Due to the ideal specificity of tail fiber protein, the method is capable of excluding the interference from other Gram-negative bacteria and all Gram-positive bacteria. It has been employed for assaying P. aeruginosa in various types of sample matrixes inclusive of lake water, physiological saline injection, human urine and milk. The acceptable assay results demonstrate its promising prospect for practical application in various areas such as environmental hygiene, medical diagnosis, as well as drug and food safety.

Bacteriófagos , Polimixina B , Pseudomonas aeruginosa/isolamento & purificação , Antibacterianos , Bactérias Gram-Negativas , Bactérias Gram-Positivas , Testes de Sensibilidade Microbiana
Talanta ; 227: 122203, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33714473


Immunochromatographic test strip (ITS) for point-of-care testing (POCT) has attracted prominent attention due to the advantages including rapid response, low cost and good portability. Here, we developed a sensitive ITS for detecting aflatoxin B1 (AFB1) by using dendritic platinum nanoparticles (DPNs) as novel pressure/colorimetric dual-readout probes. DPNs-labeled antibody of AFB1 were used as the signal tracer of the immunochromatographic process. After 10-min competitive immunoreaction, black color appeared on the test line of ITS due to the accumulation of DPNs, which was observed visually as a colorimetric readout for qualitation purpose. Furthermore, DPNs with peroxidase-like activity caused decomposition of hydrogen peroxide aqueous solution to produce pressure change signal in vials, which was detected by a hand-held pressure meter for quantitation purpose. With the pressure readout mode, the detection range was 0.05-10 ng mL-1, and the detection limit was 0.03 ng mL-1 (S/N = 3) for AFB1. The proposed ITS was successfully utilized for detecting AFB1 in herbal medicine samples, and the acceptable recoveries of 93.77-114.09% indicated the reliability for real sample detection. It provides a new avenue for POCT with great application potential in various area including drug and food quality control, pollutants monitoring as well as medical diagnosis.

Aflatoxina B1 , Nanopartículas Metálicas , Aflatoxina B1/análise , Colorimetria , Limite de Detecção , Platina , Testes Imediatos , Reprodutibilidade dos Testes
Anal Chim Acta ; 1148: 238174, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33516386


Novel cobalt-based metal-organic frameworks (Co MOFs) were synthesized by a facile "controlled synthesis" strategy. The MOFs displayed superior catalytic performance on the chemiluminescent (CL) reaction between N-(4-aminobutyl)-N-ethylisoluminol (ABEI) and H2O2. UV-vis absorption, CL spectrum, ESR, and radical scavenger experiments were conducted for clarifying the catalytic mechanism of Co MOFs. All results revealed that Co MOFs can accelerate decomposition of H2O2 and production of OH•, O2•-as well as 1O2 radicals. The rapid reaction between these reactive oxygen species and ABEI resulted in the generation of ABEI-ox∗. The excited-state oxidation product emitted a very intensive CL signal with a maximal emission wavelength of 430 nm as it returned to the ground state. To explore their application potential in CL assay, Co MOFs were used as powerful CL reaction catalyst for establishing a very sensitive method for immunoassay of aflatoxin B1. The detection range was 0.05-60 ng mL-1, and the limit of detection was 4.3 pg mL-1. The result for detecting herbal medicine samples demonstrates the acceptable reliability of the Co MOFs-based CL immunoassay. The proof-of-principle work verifies the application potential of Co MOFs on boosting intensive CL signal, and meets the demand for high sensitivity in various bioassay fields.

Estruturas Metalorgânicas , Cobalto , Peróxido de Hidrogênio , Medições Luminescentes , Luminol/análogos & derivados , Reprodutibilidade dos Testes
Chemistry ; 26(34): 7583-7588, 2020 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-32428322


Co single-atom catalysts (SACs) with good aqueous solubility and abundant labelling functional groups were prepared in Co/Fe bimetallic metal-organic frameworks by a facile solvothermal method without high-temperature calcination. In contrast to traditional chemiluminescence (CL) catalysts, Co SACs accelerated decomposition of H2 O2 to produce a large amount of singlet oxygen (1 O2 ) rather than superoxide (O2 .- ) and hydroxyl radical (OH. ). They were found to dramatically enhance the CL emission of the luminol-H2 O2 reaction by 1349 times, and, therefore, were employed as very sensitive signal probes for conducting CL immunoassay of cardiac troponin I. The detection limit of the target analyte was as low as 3.3 pg mL-1 . It is the first time that employment of SACs for boosting CL reactions has been validated. The Co SACs can also be employed to trace other biorecognition events with high sensitivity.

Radical Hidroxila/química , Luminol/química , Oxigênio Singlete/química , Catálise , Limite de Detecção , Luminescência , Medições Luminescentes/métodos , Estruturas Metalorgânicas , Superóxidos
ACS Appl Mater Interfaces ; 11(39): 35597-35603, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31502440


Nanosized metal-organic frameworks (MOFs) NH2-MIL-53(Al) were synthesized from 2-aminoterephthalic acid (NH2·H2BDC) and AlCl3 by a facile hydrothermal method. The synthesized MOFs displayed good stability and a uniform particle size in a netural medium and were hydrolyzed in alkaline medium to release a large amount of fluorescent ligand NH2·H2BDC. Therefore, they can act as large-capability nanovehicles to load signal molecules for investigating various biorecognition events. In this work, based on the alkaline hydrolysis behavior of MOFs NH2-MIL-53(Al), a sensitive immunoassay method was developed for the detection of aflatoxin B1 (AFB1) by employing them as fluorescent signal probes. With a competitive immunoassay mode on microplate, AFB1 can be detected within a linear range of 0.05-25 ng mL-1. The method was successfully employed to detect AFB1 spiked in Job tears, Polygala tenuifolia and with acceptable recovery values of 83.00-114.00%. The detection results for moldy Fructus xanthii displayed an acceptable agreement with those from the high-performance liquid chromatography method, with relative errors of -14.21 to 3.49%. With the merits of high sensitivity, facile manipulation, and ideal reliability, the approach can also be extended to other areas such as aptasensor and receptor-binding assay.

Aflatoxina B1/análise , Estruturas Metalorgânicas/química , Álcalis , Fluorimunoensaio , Hidrólise , Nanoestruturas