This work describes a surface plasmon coupling electrochemiluminescence (SPC-ECL) method for the determination of the Shiga toxin-producing Escherichia coli (STEC) gene. Firstly, gold nanoparticles (Au NPs) were encapsulated into a solid silica core (AuNP@SiO2). Secondly, graphite phase carbon nitride quantum dots (g-C3N4 QDs) were embedded in the mesoporous silica shell (mSiO2) to form nanospheres of type AuNP@C3N4QD@mSiO2. It is found that the surface plasmon coupling effect of the Au NPs in the solid silica core strongly enhances the ECL of the g-C3N4/K2S2O8 system. The mSiO2 carry much of the ECL luminophore (g-C3N4 QDs), and the co-reactant can readily pass the mesopores to react with QDs to give an ECL reaction. Because of these two features, the ECL is 3.8 times stronger compared to ECL sensing using g-C3N4 QDs only. Finally, AuNP@C3N4QD@mSiO2 was linked to the probe DNA to construct a competitive DNA sensor. When no target DNA is added, most of the capture DNA on the electrode is complementary to the probe DNA of AuNP@C3N4QD@mSiO2-probe DNA. At this time, the ECL signal is the strongest. When the target DNA is added, some of the capture DNA is paired with it and the remaining capture DNA is paired with the probe DNA. Consequently, less luminophore reaches the electrode and the signal is weaker. The method works in the 0.1 pM to 1 nM concentration range and has a 9 fM detection limit. It was successfully applied to the ultrasensitive determination of the STEC gene in human serum. Graphical abstract Schematic illustration for the “egg-yolk puff” structured ECL sensor based on Au NPs, g-C3N4 QDs, and mesoporous silica shell. Schematic illustration for the “egg-yolk puff” structured ECL sensor based on Au NPs, g-C3N4 QDs, and mesoporous silica shell.

中文翻译：

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基于 AuNP@C3N4QD@mSiO2 的表面等离子体耦合电化学发光法测定产志贺毒素大肠杆菌 (STEC) 基因

这项工作描述了一种用于测定产志贺毒素大肠杆菌 (STEC) 基因的表面等离子体耦合电化学发光 (SPC-ECL) 方法。首先，将金纳米粒子（Au NPs）封装到固体二氧化硅核（AuNP@SiO2）中。其次，将石墨相氮化碳量子点（g-C3N4 QD）嵌入介孔二氧化硅壳（mSiO2）中，形成 AuNP@C3N4QD@mSiO2 型纳米球。发现固体二氧化硅核中 Au NPs 的表面等离子体耦合效应强烈增强了 g-C3N4/K2S2O8 系统的 ECL。mSiO2 携带大部分 ECL 发光体（g-C3N4 QD），并且共反应物可以很容易地通过介孔与 QD 反应以产生 ECL 反应。由于这两个特征，与仅使用 g-C3N4 QD 的 ECL 感测相比，​​ECL 强 3.8 倍。最后，AuNP@C3N4QD@mSiO2 与探针 DNA 连接以构建竞争性 DNA 传感器。当不添加目标 DNA 时，电极上的大部分捕获 DNA 与 AuNP@C3N4QD@mSiO2-probe DNA 的探针 DNA 互补。此时ECL信号最强。当添加目标 DNA 时，一些捕获 DNA 与其配对，其余捕获 DNA 与探针 DNA 配对。因此，较少的发光体到达电极并且信号较弱。该方法在 0.1 pM 到 1 nM 的浓度范围内工作，检测限为 9 fM。成功应用于人血清中STEC基因的超灵敏测定。基于 Au NP、g-C3N4 QD 和介孔二氧化硅壳的“蛋黄泡芙”结构 ECL 传感器的图形抽象示意图。