State Key Laboratory of Dairy Biotechnology, Shanghai Engineering Research Center of Dairy Biotechnology, Dairy Research Institute, Bright Dairy & Food Co., Ltd, Shanghai, 200436, China.
School of Food & Biological Engineering, Key Laboratory for Agricultural Products Processing of Anhui Province, Hefei University of Technology, Hefei, 230009, China.
Mikrochim Acta. 2022 May 27;189(6):233. doi: 10.1007/s00604-022-05329-y.
Accurate and low-cost onsite assay of residual antibiotics in food and agriculture-related matrixes (e.g., milk) is of significant importance for evaluating and controlling food pollution risk. Herein, we employed hybrid Cu-doped-g-CN nanozyme to engineer smartphone-assisted onsite visual sensor for reliable and precise reporting the levels of tetracycline (TC) residues in milk through π-π stacking-triggered blocking effect. Benefiting from the synergetic effects of Cu and g-CN nanosheet, Cu-doped-g-CN nanocomposite exhibited an improved peroxidase-like activity, which could effectively catalyze HO to oxidate colorless TMB into steel-blue product oxTMB. Interestingly, owing to the blocking effect caused by the π-π stacking interaction between TC tetraphenyl skeleton and Cu-doped-g-CN nanozyme, the affinity of Cu-doped-g-CN nanocomposite toward the catalytic substrates was remarkably blocked, resulting in a TC concentration-dependent fading of solution color. Using smartphone-assisted detection a simple, low-cost, reliable, and sensitive portable colorimetric sensor-based nanozyme for onsite visual monitoring the residual TC in milk was successfully developed with a detection limit of 86.27 nM. Of particular mention is that this detection limit is comparable to most other reported colorimetric methods and below most official allowable residue thresholds in milk matrixes. This work gave a novel insight to integrate two-dimensional (2D) artificial nanozymes-based π-π stacking-triggered blocking effect with smartphone-assisted detection for developing efficient and low-cost colorimetric point-of-care testing of the risk factors in food and agriculture-related matrixes.
准确且低成本的现场分析食品和农业相关基质（如牛奶）中的残留抗生素对于评估和控制食物污染风险具有重要意义。在此，我们采用杂化 Cu 掺杂 g-CN 纳米酶构建智能手机辅助现场可视化传感器，通过 π-π 堆积触发的阻断效应可靠且精确地报告牛奶中环丙沙星（TC）残留水平。得益于 Cu 和 g-CN 纳米片的协同作用，Cu 掺杂 g-CN 纳米复合材料表现出增强的过氧化物酶样活性，可有效催化 HO 将无色 TMB 氧化成钢蓝色产物 oxTMB。有趣的是，由于 TC 四环骨架与 Cu 掺杂 g-CN 纳米酶之间的 π-π 堆积相互作用引起的阻断效应，Cu 掺杂 g-CN 纳米复合材料对催化底物的亲和力显著受阻，导致溶液颜色随 TC 浓度的变化而褪色。通过智能手机辅助检测，成功开发了一种简单、低成本、可靠且灵敏的基于纳米酶的便携式比色传感器现场可视化监测牛奶中残留 TC 的方法，检测限为 86.27 nM。值得注意的是，该检测限可与大多数其他报道的比色方法相媲美，且低于牛奶基质中大多数官方允许的残留阈值。这项工作为整合二维（2D）人工纳米酶基于 π-π 堆积触发的阻断效应与智能手机辅助检测用于开发高效且低成本的食品和农业相关基质中风险因素的比色即时检测提供了新的思路。
