Facile Synthesis of Enhanced Fluorescent Gold-Silver Bimetallic Nanocluster and Its Application for Highly Sensitive Detection of Inorganic Pyrophosphatase Activity
Facile Synthesis of Enhanced Fluorescent Gold-Silver Bimetallic Nanocluster and Its Application for Highly Sensitive Detection of Inorganic Pyrophosphatase Activity
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DOI：
10.1021/acs.analchem.6b02543
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发表时间：
2016-09-06
影响因子：
7.4
通讯作者：
Tang, Dianping
中科院分区：
文献类型：
--
作者：
Zhou, Qian;Lin, Youxiu;Tang, Dianping
本论文首次成功地合成了具有高荧光强度的金银双金属纳米团簇(Au-Ag NCS)，并将其应用于铜离子(Cu2+)和无机焦磷酸离子(PPI)对无机焦磷酸酶(PPase)活性的灵敏、特异的传感探针的制备。采用Cu2+作为荧光Au-Ag NC的猝灭剂，PPI作为PPase的水解底物。该体系由PPI、Cu2+离子和牛血清白蛋白(BSA)稳定的Au-Ag NC组成。该检测是通过酶促PPI的水解从Cu2+-PPI络合物中释放出铜离子来进行的。在没有目标PPase的情况下，游离铜离子首先通过配位化学与无机焦磷酸根离子形成铜-PPI络合物，从而保持了Au-Ag NCS的天然荧光强度。在检测系统中加入目标PPase后，分析物将PPI水解为磷酸根离子，并从Cu2+-PPI络合物中释放出Cu2+离子。解离的铜离子很容易猝灭Au-Ag NCS的荧光信号，从而导致荧光强度的降低。在最佳条件下，所制备的Au-Ag纳米碳管的可检测荧光强度与PPase的活性在0.1-30 mU/m L的动态范围内呈线性关系，在3s(空白)的标准下，可检测到低至0.03 m U/m L的浓度。通过使用我们的系统获得了良好的重复性(批内和批间的CV<；8.5%)、高的特异性和长期的稳定性(在48天的保存期后，初始信号的90.1%)。此外，在焦磷酸酶抑制剂的筛选研究中，利用氟化钠的抑制效率也取得了较好的效果。重要的是，该系统基于高度增强的荧光Au-Ag NCS，提供了简单且经济高效的目标PPase活性筛选，而不需要样品分离和多次洗涤步骤。
Herein, gold silver bimetallic nanoclusters (Au-Ag NCs) with the high fluorescent intensity were first synthesized successfully and utilized for the fabrication of sensitive and specific sensing probes toward inorganic pyrophosphatase (PPase) activity with the help of copper ion (Cu2+) and inorganic pyrophosphate ion (PPi). Cu2+ was used as the quencher of fluorescent Au-Ag NC, while PPi was employed as the hydrolytic substrate of PPase. The system consisted of PPi, Cu2+ ion, and bovine serum albumin (BSA)-stabilized Au-Ag NC. The detection was carried out by enzyme-induced hydrolysis of PPi to liberate copper ion from the Cu2+-PPi complex. In the absence of target PPase, free copper ions were initially chelated with inorganic pyrophosphate ions to form the Cu"-PPi complexes via the coordination chemistry, thus preserving the natural fluorescent intensity of the Au-Ag NCs. Upon addition of target PPase into the detection system, the analyte hydrolyzed PPi into phosphate ions and released Cu2+ ion from the Cu2+-PPi complex. The dissociated copper ions readily quenched the fluorescent signal of Au-Ag NCs, thereby resulting in the decrease of fluorescent intensity. Under optimal conditions, the detectable fluorescent intensity of the as-prepared Au-Ag NCs was linearly dependent on the activity of PPase within a dynamic linear range of 0.1-30 mU/mL and allowed the detection at a concentration as low as 0.03 mU/mL at the 3s(blank) criterion. Good reproducibility (CV < 8.5% for the intra-assay and interassay), high specificity, and long-term stability (90.1% of the initial signal after a storage period of 48 days) were also received by using our system toward target PPase activity. In addition, good results with the inhibition efficiency of sodium fluoride were obtained in the inhibitor screening research of pyrophosphatase. Importantly, this system based on highly enhanced fluorescent Au-Ag NCs offer promise for simple and cost-effective screening of target PPase activity without the needs of sample separation and multiple washing steps.