Abstract：
Nanozyme-mediated strategy for sensing has been widely applied nowadays, in which the construction of a nanozyme cascade platform is an effective and challenging method to simulate the complexity and multifunctionality of natural systems. Herein, a simple and convenient self-cascade sensing platform was developed for the fluorescent detection of cysteine and Hg2+ by a BTC-based MOF through screening the metal sites and crystal sizes. By the introduction of polyvinylpyrrolidone, the as-prepared Cu-BTC possessed a metal center of Cu2+ and smaller size, which exhibited both cysteine oxidase- and peroxidase-like activities. The dual enzymic characters of Cu-BTC made a self-cascade reaction occur during which cysteine was first oxidized to cystine and generated H2O2 in the presence of O2, then H2O2 was decomposed into ·OH, and finally the ·OH triggered the turn-on fluorescence of Cu-BTC. Based on the self-cascade reactions and high affinity of Hg2+ and -SH within cysteine, a fluorescent method was developed to detect cysteine and Hg2+ with a range of 0-160/0-15 μM and a limit of detection of 0.04/0.09 μM, respectively. This work reveals the important role of the Cu2+ center for mimicking cysteine oxidase and gives a feasible strategy for constructing simple self-cascade reactions.
摘要：
纳米酶介导的传感策略目前已被广泛应用,其中纳米酶级联平台的构建是模拟自然系统复杂性和多功能性的有效且具有挑战性的方法。在这里，通过筛选金属位点和晶体大小，开发了一个简单方便的自级联传感平台，用于基于BTC的MOF荧光检测半胱氨酸和Hg2。通过引入聚乙烯吡咯烷酮，制备的Cu-BTC具有Cu2+的金属中心和较小的尺寸，表现出半胱氨酸氧化酶和过氧化物酶样活性。Cu-BTC的双重酶学特性使其发生自级联反应，在O2存在下，半胱氨酸首先氧化为胱氨酸并生成H2O2，然后H2O2分解为·OH，最后，·OH触发了Cu-BTC的开启荧光。基于半胱氨酸内Hg2+和-SH的自级联反应和高亲和力，开发了一种荧光方法来检测半胱氨酸和Hg2+，范围为0-160/0-15μM，检出限为0.04/0.09μM，分别。这项工作揭示了Cu2中心在模拟半胱氨酸氧化酶中的重要作用，并为构建简单的自级联反应提供了可行的策略。
