Herein a novel ratiometric fluorescence strategy based on enzyme-triggered inner filter effect (IFE) was described to sensitively detect mercury ions (Hg²⁺) for the first time by using l-proline-protected gold nanoclusters (AuNCs) and 2,3-diaminophenazine (DAP) as IFE fluorophore and absorber. The IFE was derived from the overlap between the emission band of AuNCs and absorption band of DAP and confirmed by fluorescence lifetime decay tests. Based on IFE principle and ratiometric strategy, laccase (LACC)-catalyzed o-phenylenediamine (OPD) oxidation was utilized to produce DAP, whereas the activity of LACC can be monitored by Hg²⁺. In this way, the existence of Hg²⁺ could depress the emission of DAP while restore that of AuNCs, achieving the dual signal response of Hg²⁺, and their emission intensity ratio was dependent on the concentration of Hg²⁺. Under the optimized detection conditions, the linear range for Hg²⁺ determination was from 0.8 to 35 μM with a detection limit of 0.27 μM. Besides, it was successfully applied to the analysis of tap water and Yangtze river water. Our strategy can be used to assess the activity of LACC, and it also provided a novel way to construct other enzyme-based biosensors.

本文介绍了一种基于酶触发的内部滤光效应（IFE）的新型比例荧光方法，该方法首次使用l-脯氨酸保护的金纳米团簇（AuNCs）和2,3-灵敏地检测汞离子（Hg ²⁺）。二氨基吩嗪（DAP）作为IFE荧光团和吸收剂。IFE是从AuNCs的发射带和DAP的吸收带之间的重叠处得出的，并通过荧光寿命衰减测试来证实。基于IFE原理和比例的策略，漆酶（LACC） -催化的邻苯二胺（OPD）的氧化物来制备DAP，而LACC的活性可以通过汞被监测²⁺。这样，Hg ²⁺的存在可以抑制DAP的发射而恢复AuNCs的发射，实现Hg ²⁺的双重信号响应，其发射强度比取决于Hg ²⁺的浓度。在优化的检测条件下，用于Hg ²⁺测定的线性范围为0.8至35μM，检测极限为0.27μM。此外，它还成功地用于自来水和长江水的分析。我们的策略可用于评估LACC的活性，也为构建其他基于酶的生物传感器提供了一种新颖的方法。