State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, College of Chemistry , Nankai University , Tianjin 300071 , China.
Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research, Key Laboratory of Phytochemical R&D of Hunan Province, College of Chemistry and Chemical Engineering , Hunan Normal University , Changsha 410082 , China.
Anal Chem. 2018 Sep 18;90(18):11146-11153. doi: 10.1021/acs.analchem.8b03211. Epub 2018 Aug 28.
In this work, we demonstrate a convenient yet sensitive color-coded single-particle detection method for the quantification of pyrophosphate (PPi) by using single gold nanoparticle (GNP) as the probe. The design is based on GNP-dependent catalytic deposition of Cu onto the surface of GNPs with reduced nicotinamide adenine dinucleotide (NADH). Without PPi, Cu can be directly reduced to Cu through the gold-catalyzed oxidization of NADH. In the presence of PPi, the coating process is impeded due to the strong coordination capability of PPi with Cu. The selective coating of Cu shell onto the GNPs surface results in the extraordinary red-shift of localized surface plasmon resonance from individual GNPs. By quantitatively counting the fraction of yellow particles with color-coded dark-field optical microscopy, the trace amounts of PPi in solution can be accurately quantified. The limit-of-detection is as low as 1.49 nM with a linear dynamic range of 0-4.29 μM, which is much lower than the spectroscopic measurements in bulk solution. In artificial urine sample, good recovery efficiency was achieved. As a consequence, the method demonstrated herein will find promising applications for the ultrasensitive detection of target biomolecules under biological milieu in the future.
在这项工作中，我们展示了一种方便而灵敏的基于单金纳米粒子 (GNP) 探针的焦磷酸 (PPi) 定量的比色单颗粒检测方法。该设计基于 GNP 依赖性的 Cu 在还原型烟酰胺腺嘌呤二核苷酸 (NADH) 表面上的催化沉积。没有 PPi 时，Cu 可以通过金催化的 NADH 氧化直接还原为 Cu。在存在 PPi 的情况下，由于 PPi 与 Cu 的强配位能力，涂层过程受到阻碍。Cu 壳选择性地涂覆在 GNP 表面上，导致单个 GNP 的局域表面等离激元共振发生显著红移。通过用颜色编码的暗场光学显微镜定量计数黄色颗粒的分数，可以准确地定量溶液中痕量的 PPi。检测限低至 1.49 nM，线性动态范围为 0-4.29 μM，远低于在体相溶液中的光谱测量。在人工尿液样本中，实现了良好的回收率。因此，本文所展示的方法将有望在未来的生物环境下用于目标生物分子的超灵敏检测。
