Abstract

The crystal structures would directly affect the physical and chemical properties of the surface of the material, and would thus influence the catalytic activity of the material. α-MnO₂, β-MnO₂ and γ-MnO₂ nanorods with the same morphology yet different crystal structures were prepared and tested as oxidase mimics using 3,3’,5,5’-tetramethylbenzidine (TMB) as the substrate. β-MnO₂ that exhibited the highest activity had a catalytic constant of 83.75 μmol·m⁻²·s⁻¹, 2.7 and 19.0 times of those of α-MnO₂ and γ-MnO₂ (30.91 and 4.41 μmol·m⁻²·s⁻¹), respectively. The characterization results showed that there were more surface hydroxyls as well as more Mn⁴⁺ on the surface of the β-MnO₂ nanorods. The surface hydroxyls were conducive to the oxidation reaction, while Mn⁴⁺ was conducive to the regeneration of surface hydroxyls. The synergistic effect of the two factors significantly improved the activity of β-MnO₂ oxidase mimic. Using β-MnO₂, a β-MnO₂-TMB-GSH system was established to detect the content of glutathione (GSH) rapidly and sensitively by colorimetry. This method had a wide detection range (0.11-45 μM) and a low detection limit (0.1 μM), and had been successfully applied to GSH quantification in human serum samples.

中文翻译：

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晶体结构对MnO 2纳米棒氧化酶模拟物活性的影响

摘要

晶体结构将直接影响材料表面的物理和化学性质，并因此将影响材料的催化活性。α-MnO的₂，β-MnO的₂和γ-MnO的_2层制备并如使用3,3' ，5,5'-四甲基联苯胺（TMB）作为底物模拟物氧化酶测试的纳米棒具有相同的形态但不同的晶体结构。β-MnO的₂即表现出最高的活性有83.75微摩尔的催化常数·米^-2 ·S ^-1，2.7和那些α-的MnO的19.0倍₂和γ-MnO的₂（30.91和4.41微摩尔·米^-2 ·s ^-1）， 分别。表征结果表明，有更多的表面羟基以及更多的Mn ⁴⁺的β-MnO的表面上₂纳米棒。表面羟基有助于氧化反应，而Mn ⁴⁺有利于表面羟基的再生。这两个因素的协同效果改善显著β-MnO的活性₂氧化酶模拟物。使用β-MnO的₂，β-MnO的₂成立-TMB-GSH系统通过比色法快速和灵敏地检测谷胱甘肽（GSH）的含量。该方法检测范围广（0.11-45μM），检测限低（0.1μM），已成功应用于人血清样品中GSH的定量分析。