School of Chemistry and Environment, Yunnan Minzu University, Key Laboratory of Resource Clean Conversion in Ethnic Regions, Education Department of Yunnan, Key Laboratory of Environmental Functional Materials of Yunnan Province Education Department, Kunming 650500, PR China.
School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria 3216, Australia.
Food Chem. 2024 Jul 30;447:139020. doi: 10.1016/j.foodchem.2024.139020. Epub 2024 Mar 15.
Carbon quantum dots (CQDs) have significant applications in nanozymes. However, previous studies have not elucidated the structure-activity relationship and enzyme mechanism. In this study, we employed a one-step microwave method to synthesize ultra-trace Ag-doped carbon quantum dots (Ag-CQDs). In the presence of hydrogen peroxide (HO), we used the oxidative coupling reaction of 3,3',5,5'-tetramethylbenzidine (TMB) to evaluate the intrinsic peroxidase-like activity, kinetics, and mechanism of Ag-CQDs. The trace amount of doped Ag (1.64 %) facilitated electron transfer from the CQDs interior to the surface. The electron transfer triggered the peroxide activity of CQDs, producing hydroxyl radical (·OH), which oxidized the colorless TMB to blue-colored TMB (oxTMB). By coupling with glucose oxidase (GOx), the Ag-CQDs/HO/TMB system has been used for colorimetric glucose determination. The system demonstrated a low detection limit (0.17 µM), wide linear range (0.5-5.5 µM), and satisfactory results when fruit juice was analyzed. This study reports a feasible method for the colorimetric detection of glucose by synthesizing ultra-trace Ag-doped carbon quantum dots with peroxidase-mimicking activity.
碳量子点 (CQDs) 在纳米酶中具有重要的应用。然而，以前的研究尚未阐明其结构-活性关系和酶机制。在本研究中，我们采用一步微波法合成了超痕量银掺杂的碳量子点 (Ag-CQDs)。在存在过氧化氢 (HO) 的情况下，我们利用 3,3',5,5'-四甲基联苯胺 (TMB) 的氧化偶联反应来评估 Ag-CQDs 的固有过氧化物酶样活性、动力学和机制。痕量掺杂的 Ag (1.64%) 促进了从 CQDs 内部到表面的电子转移。电子转移引发了 CQDs 的过氧化物活性，产生了羟基自由基 (·OH)，将无色的 TMB 氧化为蓝色的 TMB (oxTMB)。通过与葡萄糖氧化酶 (GOx) 偶联，Ag-CQDs/HO/TMB 体系已用于比色法葡萄糖测定。该体系具有较低的检测限 (0.17µM)、较宽的线性范围 (0.5-5.5µM)，并且在分析果汁时得到了令人满意的结果。本研究报告了一种通过合成具有过氧化物酶模拟活性的超痕量银掺杂碳量子点来比色检测葡萄糖的可行方法。
