Key Laboratory of Analytical Chemistry for Biomedicine (Guangzhou), School of Chemistry and Environment, South China Normal University, Guangzhou, Guangdong 510006, PR China.
Key Laboratory of Analytical Chemistry for Biomedicine (Guangzhou), School of Chemistry and Environment, South China Normal University, Guangzhou, Guangdong 510006, PR China.
Spectrochim Acta A Mol Biomol Spectrosc. 2018 Apr 15;195:230-235. doi: 10.1016/j.saa.2018.01.078. Epub 2018 Feb 1.
Ratiometric fluorescent probes could eliminate the influence from experimental factors and improve the detection accuracy. In this article, a ratiometric nanoprobe was constructed based on silver nanoclusters (AgNCs) with nitrogen-doped carbon dots (NCDs) and used for the detection of biothiols. The fluorescence peak of AgNCs was observed at 650nm with excitation wavelength at 370nm. In order to construct the ratiometric fluorescent probe, NCDs with the excitation and emission wavelengths at 370nm and 450nm were selected. After adding AgNCs, the fluorescence of NCDs was quenched. The mechanism of the fluorescence quenching was studied by fluorescence, UV-Vis absorption and the fluorescence lifetime spectra. The results indicated that the quenching could be ascribed to the inner filter effect (IFE). With the addition of biothiols, the fluorescence of AgNCs at 650nm decreased due to the breakdown of AgNCs, and the fluorescence of NCDs at 450nm recovered accordingly. Thus, the relationship between the ratio of the fluorescence intensities (I/I) and biothiol concentration was used to establish the determination method for biothiols. Cysteine (Cys) was taken as the model of biothiols, and the working curve for Cys was I/I=0.60C-1.86 (C: μmol/L) with the detection limit of 0.14μmol/L (S/N=3). Then, the method was used for the detection of Cys in human urine and serum samples with satisfactory accuracy and recovery ratios. Furthermore, the probe could be applied for the visual semi-quantitative determination of Cys by naked eyes.
比率型荧光探针可以消除实验因素的影响，提高检测准确性。本文构建了一种基于银纳米簇（AgNCs）和氮掺杂碳点（NCDs）的比率型纳米探针，用于生物硫醇的检测。AgNCs 的荧光峰在 650nm 处，激发波长为 370nm。为了构建比率型荧光探针，选择了激发和发射波长分别为 370nm 和 450nm 的 NCDs。加入 AgNCs 后，NCDs 的荧光被猝灭。通过荧光、紫外-可见吸收和荧光寿命光谱研究了荧光猝灭的机制。结果表明，猝灭可以归因于内滤效应（IFE）。随着生物硫醇的加入，由于 AgNCs 的破裂，AgNCs 在 650nm 处的荧光强度降低，而 NCDs 在 450nm 处的荧光强度相应恢复。因此，利用荧光强度比（I/I）与生物硫醇浓度的关系建立了生物硫醇的测定方法。半胱氨酸（Cys）作为生物硫醇的模型，其工作曲线为 I/I=0.60C-1.86（C：μmol/L），检测限为 0.14μmol/L（S/N=3）。然后，该方法用于人尿和血清样品中 Cys 的检测，具有令人满意的准确性和回收率。此外，该探针可用于通过肉眼进行 Cys 的可视化半定量测定。
