A label-free and high sensitive fluorescence biosensor for the detection of choline and acetylcholine (ACh) was developed based on the MIL-101(Fe) nanozyme with dual functions of mimetic peroxidase and fluorescent emission. This fluorescence sensing strategy involves the reaction of acetylcholinesterase (AChE) catalyzing the hydrolysis of ACh into choline that is in turn oxidized by choline oxidase (ChOx) to generate H₂O₂, and the as-produced H₂O₂ is decomposed into highly reactive hydroxyl radicals under the catalysis of MIL-101(Fe) nanozyme, thereby the non-fluorescent organic ligand terephthalic acid of MIL-101(Fe) is oxidized by hydroxyl radicals to form a highly fluorescent 2-hydroxy terephthalic acid. By virtue of this finding, the label-free detection of choline and ACh via multienzyme cascade reaction was realized with low detection limits of 20.0 nM and 8.9 nM, respectively. Moreover, the practicality of the developed bifunctional MIL-101(Fe)-based sensing strategy was successfully validated through the detection of choline in milk and ACh in human plasma. This proposed assay not only exhibited high sensitivity and selectivity towards choline and ACh, but also simplified the sensing systems, reduced the detection cost, and avoided the potential risks caused by the fluorescent reagents, which opened a green avenue for the analysis of complex biological samples.

基于MIL-101（Fe）纳米酶，具有模拟过氧化物酶和荧光发射双重功能，开发了一种用于检测胆碱和乙酰胆碱（ACh）的无标记，高灵敏度的荧光生物传感器。这种荧光传感策略涉及乙酰胆碱酯酶（AChE）催化ACh水解为胆碱，然后被胆碱氧化酶（ChOx）氧化生成H ₂ O ₂和生成的H ₂ O _{2的反应。}在MIL-101（Fe）纳米酶的催化下被分解成高反应性羟基自由基，从而MIL-101（Fe）的非荧光有机配体对苯二甲酸被羟基自由基氧化而形成高荧光性2-羟基对苯二甲酸。根据这一发现，通过多酶级联反应实现了胆碱和乙酰胆碱的无标记检测，检测限分别为20.0 nM和8.9 nM。此外，通过检测牛奶中的胆碱和人血浆中的ACh，已成功验证了开发的基于MIL-101（Fe）的双功能传感策略的实用性。该拟议的测定方法不仅表现出对胆碱和ACh的高灵敏度和选择性，而且简化了传感系统，降低了检测成本，