AbstractIsotropic silver nanoparticles (iAg NPs) can be easily prepared at low costs, have a low electrochemical potential and high extinction coefficient. An effective colorimetric assay for H2O2 is reported here based on the finding that H2O2 can induce the shape transformation of citrate-capped iAg NPs with the help of citrate. The substantial shape variation affords an apparent surface plasmon resonance (SPR) shift, accompanied by a vivid color change from light yellow to mauve. The color change can be observed visually if the concentration of H2O2 is 2 μM or higher. A good linear relationship was obtained over the concentration range of 0.2–32 μM with a limit of detection of 90 nM. By making use of glucose oxidase, the method is further extended to glucose detection. Glucose at a concentration as low as 10 μM can be well determined with bare eyes. Benefitting from the high selectivity, the detection of glucose in human serum is realized, and the results are in good agreement with those provided by a clinical analyzer. Graphical abstractSchematic presentation of a colorimetric assay for H2O2 and glucose based on citrate-promoted H2O2-mediated shape transformation of the isotropic silver nanoparticles (Ag NPs). The shape variation of isotropic Ag NPs induces a color change from light yellow to mauve.

中文翻译：

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基于柠檬酸盐促进 H2O2 雕刻银纳米粒子的 H2O2 和葡萄糖的视觉和比色测定

摘要 各向同性银纳米粒子 (iAg NPs) 易于制备、成本低、电化学势低、消光系数高。基于 H2O2 可以在柠檬酸盐的帮助下诱导柠檬酸盐封端的 iAg NPs 的形状转变的发现，这里报告了一种有效的 H2O2 比色测定。巨大的形状变化提供了明显的表面等离子体共振 (SPR) 偏移，伴随着从浅黄色到紫红色的生动颜色变化。如果 H2O2 的浓度为 2 μM 或更高，则可以目视观察颜色变化。在 0.2-32 μM 的浓度范围内获得了良好的线性关系，检测限为 90 nM。通过利用葡萄糖氧化酶，该方法进一步扩展到葡萄糖检测。浓度低至 10 μM 的葡萄糖可以用肉眼很好地确定。得益于高选择性，实现了人血清中葡萄糖的检测，结果与临床分析仪提供的结果吻合良好。图形摘要基于柠檬酸盐促进的 H2O2 介导的各向同性银纳米粒子 (Ag NPs) 形状转变的 H2O2 和葡萄糖比色分析的示意图。各向同性 Ag NPs 的形状变化会导致颜色从浅黄色变为紫红色。图形摘要基于柠檬酸盐促进的 H2O2 介导的各向同性银纳米粒子 (Ag NPs) 形状转变的 H2O2 和葡萄糖比色分析的示意图。各向同性 Ag NPs 的形状变化会导致颜色从浅黄色变为紫红色。图形摘要基于柠檬酸盐促进的 H2O2 介导的各向同性银纳米粒子 (Ag NPs) 形状转变的 H2O2 和葡萄糖比色分析的示意图。各向同性 Ag NPs 的形状变化会导致颜色从浅黄色变为紫红色。