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1.
Nanoscale ; 13(29): 12546-12552, 2021 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-34477613

RESUMO

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.


Assuntos
Estruturas Metalorgânicas , Infecções Estafilocócicas , Animais , Corantes Fluorescentes , Hidrólise , Infecções Estafilocócicas/diagnóstico , Staphylococcus aureus , Suínos
2.
ACS Appl Mater Interfaces ; 11(39): 35597-35603, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31502440

RESUMO

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.


Assuntos
Aflatoxina B1/análise , Estruturas Metalorgânicas/química , Álcalis , Fluorimunoensaio , Hidrólise , Nanoestruturas
3.
Talanta ; 195: 706-712, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30625605

RESUMO

Organophosphorus pesticide (OP) residues in agricultural products, herbal medicines and environment have attracted increasing concerns because they cause high healthy risk. Herein, a tyrosinase-mediated photoinduced electron transfer system was constructed for OPs analysis by using dopamine-functionalized upconversion nanoparticles (UCNPs) as fluorescent (FL) sensors. Dopamine quinone was produced by tyrosinase-mediated oxidation of dopamine on the surface of UCNPs, which acted as electron accepter to quench the FL emission of UCNPs. The FL quenching was inhibited by OP since it inhibited the activity of tyrosinase. Chlorpyrifos was used as a model analyte to investigate the feasibility of the FL sensor for the analysis of OPs. Under the optimal conditions, chlorpyrifos can be analysed in a wide range of 1.0 ‒ 1000 ng mL-1, with a detection limit of 0.38 ng mL-1 (3σ). Some other groups pesticides, including organonitrogen pesticide, organochlorine pesticide and chloronicotinyl insecticide all showed negligible interference. The proposed sensor was successfully used to analyse chlorpyrifos spiked in Balloonflower and Angelica with acceptable recovery values of 95.4-120.0%, demonstrating its application potential for real samples. It exhibits some advantages like low cost, high sensitivity and free of autofluorescent interference and photobleaching.


Assuntos
Clorpirifos/análise , Dopamina/análogos & derivados , Corantes Fluorescentes/química , Inseticidas/análise , Metais Terras Raras/química , Nanopartículas/química , Angelica/química , Campanulaceae/química , Clorpirifos/química , Dopamina/química , Inseticidas/química , Monofenol Mono-Oxigenase/química
4.
Chemistry ; 19(47): 16087-92, 2013 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-24123196

RESUMO

Pt-based nanostructures serving as anode catalysts for the methanol oxidation reaction (MOR) have been widely studied for many years. Nevertheless, challenging issues such as poor reaction kinetics and the short-term stability of the MOR are the main drawbacks of such catalysts and limit their applications. Herein, we have developed a facile approach to encapsulate Pt nanoparticles (NPs) inside the nanochannels of porous carbon nanotubes (CNTs; Pt-in-CNTs) as a new enhanced electrocatalytic material. The as-prepared CNTs offer simultaneously ordered diffusion channels for ions and a confinement effect for the NPs, which both facilitate the promotion of catalytic kinetics and avoid the Ostwald ripening of Pt NPs, thus leading to high activity and durable cycle life as an anode catalyst for MOR. This work provides a new approach for enhancing the stability and activity by optimizing the structure of the catalyst, and the Pt-in-CNTs represent the most durable catalysts ever reported for MOR.

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