College of Food Science and Engineering, Wuhan Polytechnic University, Wuhan 430023, China; Key Laboratory for Deep Processing of Major Grain and Oil, Ministry of Education, Hubei Key Laboratory for Processing and Transformation of Agricultural Products, Wuhan Polytechnic University, Wuhan 430023, China.
College of Food Science and Engineering, Wuhan Polytechnic University, Wuhan 430023, China; Key Laboratory for Deep Processing of Major Grain and Oil, Ministry of Education, Hubei Key Laboratory for Processing and Transformation of Agricultural Products, Wuhan Polytechnic University, Wuhan 430023, China.
Food Chem. 2024 Jul 1;445:138749. doi: 10.1016/j.foodchem.2024.138749. Epub 2024 Feb 15.
In this study, a type of luminescent porous coordination network-224 (PCN-224) in alkaline conditions was synthesized with the dramatic fluorescence enhancement by 20.4 times, which was explained by the fact that the decrease of Zr content in alkaline conditions resulted in the partial recovery of the electron cloud density of 4,4',4'',4'''-(Porphine-5,10,15,20-tetrayl) tetrakis(benzoic acid) (TCPP). Given the large overlap between the excitation spectrum of PCN-224 and the absorption band of Ag nanoparticles (Ag NPs), the coating of the Ag layer on PCN-224 triggered the fluorescence quenching effect, which was applied to "turn off" fluorescence immunoassay for sensitive detection of Escherichia coli O157:H7 (E. coli O157:H7) in milk. The proposed immunoassay reached a low limit of detection (LOD) of 3.3 × 10 CFU mL, 29.7 times more sensitive than the conventional ELISA. It will provide a novel alternative strategy for sensitively detecting pathogenic bacteria in the field of food safety.
在这项研究中，在碱性条件下合成了一种发光多孔配位网络-224（PCN-224），其荧光强度增强了 20.4 倍，这可以解释为碱性条件下 Zr 含量的降低导致 4,4',4'',4'''-(卟啉-5,10,15,20-四羧酸)四(苯甲酸)(TCPP)的电子云密度部分恢复。鉴于 PCN-224 的激发光谱与银纳米粒子（Ag NPs）的吸收带之间有很大的重叠，因此在 PCN-224 上涂覆 Ag 层会触发荧光猝灭效应，这可用于“关闭”荧光免疫分析，以灵敏检测牛奶中的大肠杆菌 O157:H7（E. coli O157:H7）。所提出的免疫分析方法的检测限（LOD）达到了 3.3×10 CFU mL，比传统 ELISA 灵敏 29.7 倍。它将为食品安全领域中灵敏检测致病菌提供一种新的替代策略。
