Liu Haijian, Li Ming, Xia Yining, Ren Xueqin
Department of Environmental Science and Engineering, College of Resources and Environmental Sciences, China Agricultural University , Beijing 100193, China.
Institute of Quality Standards and Testing Technology for Agro Products of Chinese Academy of Agricultural Sciences , Beijing 100081, China.
ACS Appl Mater Interfaces. 2017 Jan 11;9(1):120-126. doi: 10.1021/acsami.6b11920. Epub 2016 Dec 22.
In this work, a novel approach for simple and sensitive determination of alkaline phosphatase (ALP) is developed on the basis of an inner filter effect of p-nitrophenylphosphate (PNPP) on the fluorescence of gold nanoclusters (AuNCs). AuNCs with a high quantum yield of 12% were synthesized by one-pot strategy and were directly applied as fluorescent substance. When AuNCs were mixed with PNPP, the fluorescence of the AuNCs was remarkably quenched or was decreased via the inner filter effect since the absorption spectrum of PNPP overlaps well with the excitation spectrum of the AuNCs. While in the presence of ALP, PNPP was catalytically hydrolyzed into p-nitrophenol, which has different absorption characteristics from those of PNPP, resulting in the recovery of the AuNCs fluorescence. Thus, a novel "turn-on" fluorescent sensor for detecting ALP was established with a detection limit as low as 0.002 U/L (signal-to-noise ratio of 3). The turn-on fluorescent sensor exhibits many merits such as high sensitivity, excellent selectivity, and high signal output because of the low background signals. In addition, the developed sensing method was successfully applied to investigate ALP inhibitors and ALP determination in serum samples. A good linear relationship was obtained in the range from 0.02 to 50 U/L, and satisfactory recoveries at four spiking levels of ALP ranged from 95% to 106% with precision below 5%. The very simple sensing approach proposed here should promote the development of fluorescence turn-on chemosensors for chemo/biodetection.
在本工作中，基于对硝基苯磷酸酯（PNPP）对金纳米簇（AuNCs）荧光的内滤效应，开发了一种简单灵敏地测定碱性磷酸酶（ALP）的新方法。通过一锅法合成了量子产率高达12%的AuNCs，并将其直接用作荧光物质。当AuNCs与PNPP混合时，由于PNPP的吸收光谱与AuNCs的激发光谱有很好的重叠，AuNCs的荧光通过内滤效应显著猝灭或降低。而在ALP存在的情况下，PNPP被催化水解为对硝基苯酚，其吸收特性与PNPP不同，导致AuNCs荧光恢复。因此，建立了一种用于检测ALP的新型“开启”荧光传感器，检测限低至0.002 U/L（信噪比为3）。由于背景信号低，该开启式荧光传感器具有高灵敏度、优异的选择性和高信号输出等诸多优点。此外，所开发的传感方法成功应用于研究ALP抑制剂以及血清样品中ALP的测定。在0.02至50 U/L范围内获得了良好的线性关系，在四个加标水平下ALP的回收率令人满意，范围为95%至106%，精密度低于5%。这里提出的非常简单的传感方法应能促进用于化学/生物检测的荧光开启化学传感器的发展。
