Gold nanoclusters (AuNCs), stabilized and functionalized by organic ligands, have served as new generation materials for applications in nanocatalysis. To further expand and regulate the catalytic function of AuNCs, the exploration of surface interactions and modulated-ligand properties is highly desirable. This study presents the fabrication of four kinds of AuNCs using L-proline-methyl ester derivatives as ligands. Among these AuNCs nanocatalysts, the highest peroxidase-mimic catalytic activity in an oxidation reaction of 3,3′,5,5′-tetramethylbenzidine (TMB) with hydrogen peroxide is observed when using L-proline-methyl ester capped AuNCs (POMe@AuNCs) as the nanozymes. Notably, the addition of ofloxacin in the oxidation system yields more reactive oxygen species, resulting in a significant increase in catalytic capability. A colourimetric sensing strategy is developed for the highly selective and sensitive measurement of ofloxacin. The UV-vis absorption of oxTMB at 650 nm exhibits a good linear relationship with the ofloxacin amount, ranging from 0.6 μM to 12.0 μM (R² = 0.998), and the detection limit is 0.2 μM. The protocol further displays its potential application in monitoring rat serum ofloxacin variation in a drug-metabolic-process. This study not only demonstrates a unique strategy for the ligand-modulated synthesis of AuNCs, but also guides future detection of drugs that can enhance the catalytic capability of AuNCs.

中文翻译：

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L-脯氨酸甲酯衍生物调节合成具有促进过氧化物酶模拟活性的金纳米簇用于监测氧氟沙星

由有机配体稳定和功能化的金纳米团簇 (AuNC) 已成为用于纳米催化应用的新一代材料。为了进一步扩展和调节 AuNCs 的催化功能，非常需要探索表面相互作用和调制配体特性。本研究介绍了使用L-脯氨酸-甲酯衍生物作为配体制备四种 AuNCs 。在这些 AuNCs 纳米催化剂中，当使用L-脯氨酸甲酯封端的AuNCs（POMe@AuNCs）作为纳米酶。值得注意的是，在氧化系统中添加氧氟沙星会产生更多的活性氧，从而显着提高催化能力。为氧氟沙星的高选择性和灵敏测量开发了一种比色传感策略。oxTMB 在 650 nm 处的紫外可见吸收与氧氟沙星用量呈良好的线性关系，范围为 0.6 μM 至 12.0 μM ( R ²= 0.998)，检测限为 0.2 μM。该协议进一步展示了其在监测药物代谢过程中大鼠血清氧氟沙星变化方面的潜在应用。该研究不仅展示了一种独特的配体调节合成 AuNCs 的策略，而且还指导未来检测可以增强 AuNCs 催化能力的药物。