Guanosine 3'-diphosphate-5'-di(tri)phosphate (ppGpp) plays a crucial role in the gene expression, metabolism, growth, and other significant processes of microorganisms. In this work, a facile sensitive and visual strategy for the detection of ppGpp has been established by developing a colorimetric probe of copper ions (Cu2+)-mediated 4-mercaptobenzoic acid (4-MBA) modified gold nanoparticles (AuNPs). The sensing process was characterized by transmission electron microscopy (TEM), zeta potential, dynamic light scattering (DLS) and UV-vis spectroscopy. The strategy not only achieves desirable performance over a wide concentration range (0.05-10 μM), but also exhibits excellent selectivity over other nucleotides and biomolecules. In addition, the results could be visualized by the naked eye. We have demonstrated the determination of ppGpp in Bacillus subtilis lysate samples.

中文翻译：

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基于铜离子介导的 4-巯基苯甲酸修饰金纳米粒子的细菌中鸟苷 3'-二磷酸-5'-二(三)磷酸 (ppGpp) 的高灵敏度和视觉检测

鸟苷 3'-二磷酸-5'-二(三)磷酸 (ppGpp) 在微生物的基因表达、代谢、生长和其他重要过程中起着至关重要的作用。在这项工作中，通过开发铜离子 (Cu2+) 介导的 4-巯基苯甲酸 (4-MBA) 修饰的金纳米粒子 (AuNPs) 的比色探针，建立了一种用于检测 ppGpp 的简便灵敏的视觉策略。传感过程通过透射电子显微镜 (TEM)、zeta 电位、动态光散射 (DLS) 和紫外-可见光谱进行表征。该策略不仅在较宽的浓度范围 (0.05-10 μM) 内实现了理想的性能，而且还表现出优于其他核苷酸和生物分子的选择性。此外，结果可以通过肉眼看到。