Department of Chemistry, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China.
Textile Industrial Products Testing Center of Nanjing Customs District, Wuxi 210001, China.
Molecules. 2022 Oct 30;27(21):7379. doi: 10.3390/molecules27217379.
The construction of novel fluorescent nanozymes is highly desirable for providing new strategies for nanozyme-based sensing systems. Herein, a novel ratiometric fluorescence sensing platform was constructed based on carbon dots (CDs) as both luminophores and nanozymes, which could realize the sensitive detection of hydrogen peroxide (HO). CDs with peroxidase-mimicking activity were prepared with a one-step hydrothermal method using -histidine as an inexpensive precursor. CDs had bright blue fluorescence. Due to the pseudo-peroxidase activity, CDs catalyzed the oxidation of o-phenylenediamine (OPD) with HO to generate 2,3-diaminophenolazine (DAP). The fluorescence resonance energy transfer (FRET) between CDs and DAP resulted in a decrease in the fluorescence of CDs and an increase in the fluorescence of DAP, leading to a ratiometric fluorescence system. The free radical trapping experiment was used to investigate the reactive oxygen radicals (ROS) in the catalytic process of CD nanozymes. The enzymatic parameters of CD nanozymes, including the Michaelis constant () and the maximum initial reaction velocities (), were investigated. A good affinity for both OPD and HO substrates was proven. Based on the FRET between CDs and OPD, a ratiometric fluorescence analysis of HO was achieved and results ranged from 1 to 20 μM and 20 to 200 μM with a low limit of detection (LOD, 0.42 μM). The detection of HO in milk was also achieved.
构建新型荧光纳米酶对于为基于纳米酶的传感系统提供新策略是非常可取的。本文构建了一种新型比率荧光传感平台，该平台以碳点（CDs）作为发光体和纳米酶，可实现对过氧化氢（HO）的灵敏检测。以 -组氨酸为廉价前体，采用一步水热法制备了具有过氧化物酶模拟活性的 CDs。CDs 具有明亮的蓝色荧光。由于具有类过氧化物酶活性，CDs 可以催化 HO 氧化邻苯二胺（OPD）生成 2,3-二氨基吩嗪（DAP）。CDs 和 DAP 之间的荧光共振能量转移（FRET）导致 CDs 的荧光降低和 DAP 的荧光增加，从而形成比率荧光系统。自由基捕获实验用于研究 CD 纳米酶催化过程中的活性氧（ROS）。研究了 CD 纳米酶的酶学参数，包括米氏常数（）和最大初始反应速率（）。证明了对 OPD 和 HO 底物都具有良好的亲和力。基于 CDs 和 OPD 之间的 FRET，实现了对 HO 的比率荧光分析，检测范围为 1 至 20 μM 和 20 至 200 μM，检测限（LOD，0.42 μM）低。还实现了对牛奶中 HO 的检测。
