Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang 330013, P. R. China.
Anal Methods. 2021 Jan 28;13(3):322-326. doi: 10.1039/d0ay02129f.
Herein, we simply synthesized intrinsic fluorescent polydopamine nanoparticles (PDA NPs) in sodium hydroxide solution (NaOH, pH 11), and constructed a new fluorescence nanoplatform for the detection of alkaline phosphatase (ALP) using PDA NPs as an effective signal reporter. The nanoplatform was constructed by the combination of enzymatic hydrolysis of ALP to the substrate l-ascorbic acid-2-phosphate (AA2P) and the chemical redox reaction between l-ascorbic acid (AA) and mercury ion (Hg2+). The fluorescence of PDA NPs could be effectively quenched by Hg2+ through the coordination effect between Hg2+ and the functional groups on the surface of PDA NPs. However, the quenching effect was greatly inhibited by the addition of AA into the solution. Based on this point, the activity of ALP could be monitored by hydrolysis of the substrate AA2P to AA and the fluorescence output of PDA NPs. The nanoplatform exhibited high sensitivity and desirable selectivity for ALP detection. With a wide linear range of 0 to 18 U L-1, a detection limit of 0.4 U L-1 was achieved using the developed nanosensor. The proposed method could not only be used to screen the inhibitor of ALP but also be used to detect ALP activity in human serum samples successfully. Moreover, the strategy can easily be expanded to determining other kinds of enzymes participating in AA-generation reactions.
在此，我们在氢氧化钠溶液（NaOH，pH 值 11）中简单地合成了内荧光聚多巴胺纳米粒子（PDA NPs），并构建了一种新的荧光纳米平台，用于检测碱性磷酸酶（ALP），该平台是通过 ALP 将底物 l-抗坏血酸-2-磷酸（AA2P）水解以及 l-抗坏血酸（AA）和汞离子（Hg2+）之间的化学氧化还原反应构建而成的。PDA NPs 的荧光可以通过 Hg2+与 PDA NPs 表面官能团之间的配位作用被 Hg2+有效猝灭。然而，加入 AA 会大大抑制溶液中 Hg2+的猝灭效应。基于这一点，可以通过水解 AA2P 生成 AA 以及 PDA NPs 的荧光输出来监测 ALP 的活性。该纳米平台对 ALP 的检测表现出高灵敏度和理想的选择性。该纳米传感器的线性范围为 0 至 18 U L-1，检测限为 0.4 U L-1。该方法不仅可用于筛选 ALP 的抑制剂，还可成功用于检测人血清样品中的 ALP 活性。此外，该策略可以很容易地扩展到测定参与 AA 生成反应的其他种类的酶。
