College of Chemistry and Environment, Weifang University of Science and Technology, Shouguang, Weifang, 262700, China.
Department of Environmental Science and Engineering, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China.
Anal Bioanal Chem. 2019 May;411(12):2531-2543. doi: 10.1007/s00216-019-01693-6. Epub 2019 Mar 4.
In this work, a novel ratiometric fluorescent sensor, based on carbon dots (CDs) and gold nanoclusters (AuNCs), is developed for highly sensitive and selective visual colorimetric detection of Cu and alkaline phosphatase (ALP). The ratiometric fluorescent sensor was synthesized by covalently linking 11-mercaptoundecanoic acid (11-MUA)-stabilized AuNCs to the surface of amino-functionalized CD/SiO nanoparticles. The red fluorescence of the AuNCs can be quenched by Cu owing to coordination between Cu and 11-MUA; however, the blue emission of the CDs was insensitive to Cu owing to the protective silica shell. The quenching of the AuNCs' fluorescence returned when PPi was added because of the higher affinity between Cu and PPi than that between Cu and 11-MUA. In the presence of ALP, PPi was catalytically hydrolyzed into phosphate (Pi), which showed a much weaker affinity for Cu. Thus, Cu ions were released, and the fluorescence of the AuNCs was quenched once more. Based on this principle, Cu and ALP could be simultaneously detected. The developed ratiometric fluorescent sensor could detect Cu over a range from 0.025 to 4 μM with a detection limit of 0.013 μM and ALP over a range from 0.12 to 15 U/L with a detection limit of 0.05 U/L. The present method was successfully applied for the detection of Cu and ALP in real water samples and in human serum samples, respectively. This ratiometric fluorescent approach may provide a highly sensitive and accurate platform for visual Cu and ALP sensing in environmental monitoring and medical diagnosis.
在这项工作中，开发了一种基于碳点（CDs）和金纳米簇（AuNCs）的新型比率荧光传感器，用于高灵敏度和选择性的目视比色法检测 Cu 和碱性磷酸酶（ALP）。该比率荧光传感器是通过将 11-巯基十一酸（11-MUA）稳定的 AuNCs共价连接到氨基功能化的 CD/SiO2 纳米粒子表面来合成的。由于 Cu 与 11-MUA 的配位，AuNCs 的红色荧光可以被 Cu 猝灭；然而，由于保护性二氧化硅壳，CDs 的蓝色发射对 Cu 不敏感。当添加 PPi 时，由于 Cu 与 PPi 之间的亲和力高于 Cu 与 11-MUA 之间的亲和力，AuNCs 的荧光猝灭得到恢复。在存在 ALP 的情况下，PPi 被催化水解成磷酸盐（Pi），它与 Cu 的亲和力要弱得多。因此，Cu 离子被释放，AuNCs 的荧光再次被猝灭。基于这一原理，可以同时检测 Cu 和 ALP。所开发的比率荧光传感器可以检测 0.025 至 4 μM 范围内的 Cu，检测限为 0.013 μM，12 至 15 U/L 范围内的 ALP，检测限为 0.05 U/L。该方法成功地应用于实际水样和人血清样品中 Cu 和 ALP 的检测。这种比率荧光方法可能为环境监测和医学诊断中 Cu 和 ALP 的可视化传感提供一个高灵敏度和准确的平台。
