AbstractThe authors have synthesized molybdenum disulfide nanosheets (MoS2 nanosheets) by using a bottom-up hydrothermal method. The nanosheets display strong catalytic (enzyme mimetic) activity in catalyzing the oxidation of peroxidase substrate of 3,3′,5,5′-tetramethylbenzidine (TMB) in presence of H2O2 to produce a blue product. The peroxidase mimicking properties of MoS2 nanosheets depend on temperature, H2O2 concentration and pH value. A choline assay was worked out where choline was oxidized by choline oxidase in presence of oxygen to produce H2O2 which is colorimetrically detected, best at 652 nm. The method works in the 1 to 180 μM choline concentration range with a 0.4 μM detection limit. Color changes may also be detected visually. The assay is simple, highly sensitive, selective and rapid. It was applied in the determination of choline in (spiked) milk and serum. Graphical abstractBasic principle of intrinsic peroxidase-like activity of MoS2 nanosheets, applied to design a rapid and selective colorimetric assay for choline detection based on the tetramethylbenzidine (TMB) color reaction.

中文翻译：

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基于使用二硫化钼纳米片作为高活性酶模拟物快速比色测定牛奶和血清中的胆碱

摘要 作者采用自下而上的水热法合成了二硫化钼纳米片（MoS2 纳米片）。纳米片在 H2O2 存在下催化 3,3',5,5'-四甲基联苯胺 (TMB) 的过氧化物酶底物氧化产生蓝色产物方面显示出很强的催化（酶模拟）活性。MoS2 纳米片的过氧化物酶模拟特性取决于温度、H2O2 浓度和 pH 值。胆碱测定是在氧气存在下被胆碱氧化酶氧化产生 H2O2 的，H2O2 可在 652 nm 下进行比色检测。该方法适用于 1 至 180 μM 胆碱浓度范围，检测限为 0.4 μM。还可以视觉检测颜色变化。该测定简单、高度灵敏、选择性和快速。它用于测定（加标）牛奶和血清中的胆碱。图形摘要 MoS2 纳米片内在过氧化物酶样活性的基本原理，用于设计一种基于四甲基联苯胺 (TMB) 显色反应的胆碱检测快速选择性比色法。