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Anal Chim Acta ; 1098: 102-109, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31948572


Ratiometric analysis of dopamine (DA) in complex biological system is urgently desired. In this work, a novel dual-emission fluorescence probe was fabricated by embedding both gold nanoclusters (AuNCs) and poly(9,9-dioctylfluorenyl-2,7-diyl) (PFO) dots into zeolitic imidazolate framework-8 (ZIF-8) (abbreviated as ZIF-8@AuNCs-PFO) and applied to ratiometric analysis of DA. Remarkably, encapsulating AuNCs and PFO dots into ZIF-8 not only achieved an excellent aggregation induced emission (AIE) enhancement effect on AuNCs (5 times increase), but also brought about an unique DA-triggered asynchronous fluorescence changes of AuNCs and PFO dots. The as-prepared probe exhibited excellent performance toward DA in the concentrations range from 0.01 to 10000 µmol L-1 and good selectivity over interfering substances. The detection limit of DA was as low as 4.8 nmol L-1. Furthermore, good stability and practicability of the probe in human serum samples suggesting its great potential for diagnostic purposes. Moreover, the quenching mechanism of AuNCs was intensively studied and summarized as three synergistic processes: (i) electron transfer between AuNCs and DA; (ii) DA-triggered architecture change of ZIF-8; (iii) fluorescence resonance energy transfer (FRET) between AuNCs and polydopamine (PDA), which offered an important theory for ZIF-based fluorescent probes.

Talanta ; 208: 120460, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31816722


Probing the level and activity of alkaline phosphatases (ALP) is of great significance for biomedical research on cellular functions and clinical diagnosis of cancers. Herein, a novel dual-colored carbon dots (CDs)-based ratiometric fluorescent sensor was constructed to accomplish high sensitive and accurate determination of ALP relyed on the difference of fluorescence resonance energy transfer (FRET) between blue light emitted CDs (B-CDs)-MnO2 nanohybrid and yellow light emitted CDs (Y-CDs)-MnO2 nanohybrid. The ratiometric fluorescent sensor enabled sensitive discrimination of ALP against other enzymes in a linear range of 0.1-500 U/L with a limit of detection of 0.02 U/L. The lower error and signal fluctuation, more satisfactory LODs and higher R value (R2 = 0.99552) of the ratiometric sensing platform than single signal detection mode (R2 = 0.85231; R2 = 0.64260) indicated the superiority of the ratiometric fluorescence detection mode.Besides, the excellent analytical performance towards ALP in biological system demonstrated the potential application in clinical diagnosis.

J Fluoresc ; 27(5): 1597-1605, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28401410


In this paper, a rapid, simple and highly sensitive method with dual-readout (colorimetric and fluorometric) based on the nanometal surface energy transfer (NSET) between nitrogen-doped carbon quantum dots (NCQDs) and gold nanoparticles (AuNPs) for detection of biothiols is described. Highly luminescent NCQDs were prepared via a simple one-step hydrothermal method by applying sucrose and glycine as carbon and nitrogen sources. The results showed the obtained NCQDs had an average particle diameter of 5 nm and highly luminescent. The maximum emission wavelength was 438 nm with an excitation wavelength of 360 nm. In this system, NCQDs and AuNPs were respectively treated as energy donors and energy acceptors, which enable the nanometal surface energy transfer (NSET) from the NCQDs to the AuNPs, quenching the fluorescence. However, biothiols was used as a competitor in the NSET by the strongly Au-S bonding to release NCQDs from the Au surface, which subsequently produces fluorescent signal recovery and the red-to-purple color change quickly. This probe showed rapid response, high selectivity and sensitivity for biothiols with dual colorimetric and fluorescent turn-on signal changes. The low detection limit was calculated as 20 nM by using L-cysteine acted as target melocules. The method was also successfully applied to the determination of biothiols in human serum samples, and the results were satisfying.

Técnicas Biossensoriais/métodos , Carbono/química , Ouro/química , Nanopartículas Metálicas/química , Nitrogênio/química , Pontos Quânticos/química , Compostos de Sulfidrila/sangue , Transferência de Energia , Corantes Fluorescentes/química , Humanos , Limite de Detecção , Espectrometria de Fluorescência