This study demonstrates a novel and convenient ratiometric fluorescent method for the detection of alkaline phosphatase (ALP) activity. Amino-functionalized mesoporous silica nanoparticle-gold nanoclusters (MSN-AuNCs) nanocomposites were integrated with o-phenylenediamine (OPD) to form a ratiometric fluorescence nanoplatform. The presence of ALP induced the generation of quinoxaline (QX) derivative which called 3-(dihydroxyethyl)furo[3,4-b]quinoxaline-1-one (DFQ) with strong fluorescence emission at 450 nm, while the orange-red fluorescence of MSN-AuNCs at 580 nm was slightly quenched. Meanwhile, an obvious fluorescence color change from orange-red to purple and finally to blue can be observed by naked eyes with the increasing of ALP concentration. Therefore, employing the fluorescence emission of DFQ at 450 nm as the reporter signal and the fluorescence emission of MSN-AuNCs at 580 nm as a reference signal, a sensitive ratiometric detection method for ALP was developed. Quantitative detection of ALP activity in the linear range from 0.2 to 80 U/L with a detection limit of 0.1 U/L can be realized in this way, which endows the assay with high sensitivity enough for practical detection of ALP in human serum samples.

中文翻译：

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基于邻苯二胺/金纳米团簇的纳米平台，用于碱性磷酸酶活性的比例荧光检测。

这项研究表明检测碱性磷酸酶（ALP）活性的新颖和方便的比例荧光方法。将氨基官能化的介孔二氧化硅纳米颗粒-金纳米团簇（MSN-AuNCs）纳米复合材料与邻苯二胺（OPD）集成在一起，形成比例荧光纳米平台。ALP的存在诱导了喹喔啉（QX）衍生物的生成，该衍生物称为3-（二羟乙基）呋喃[3,4-b]喹喔啉-1-一（DFQ），在450 nm处具有强荧光发射，而橙红色荧光580 nm处的MSN-AuNC略微淬灭。同时，随着ALP浓度的增加，肉眼可以观察到明显的荧光色变化，从橙红色到紫色，最后到蓝色。因此，以DFQ在450 nm处的荧光发射为报告信号，MSN-AuNCs在580 nm处的荧光发射为参考信号，开发了一种灵敏的ALP比率检测方法。通过这种方式可以定量检测ALP活性的线性范围为0.2到80 U / L，检测极限为0.1 U / L，这赋予了该检测方法足够高的灵敏度，可以实际检测人血清样品中的ALP。