晶体结构对FeOOH类过氧化物酶活性的影响及其在Hg^(2+)检测中的应用

Effect of crystal structure on the peroxidase-like activity of FeOOH nanozyme and its application in Hg^(2+)detection

纳米酶的催化活性很大程度上依赖于纳米材料自身的晶体结构和理化性质.本研究可控合成了三种具有不同晶体结构的羟基氧化铁(α-FeOOH、β-FeOOH、γ-FeOOH)纳米晶,并系统研究了其类过氧化物酶活性的差异及其机制.结果表明,相比另外两种晶体结构,γ-FeOOH具有更高的类过氧化物酶活性,其催化常数分别是α-FeOOH和β-FeOOH的2.0和2.6倍,这归因于γ-FeOOH表面的Fe^(2+)/Fe^(3+)高于α-FeOOH和β-FeOOH.进一步基于γ-FeOOH的优异类过氧化物酶活性,以维生素B1为底物,本文建立了一种快速、高灵敏、高选择性的荧光新方法用于Hg^(2+)检测,其检测范围为10~100 nM,检出限为2 n M,并成功应用于日用化妆品中Hg^(2+)的含量测定.这项工作为通过调控晶体结构获得高效催化活性的酶模拟物提供了有效途径,并基于纳米酶催化原理开发了一种检测Hg^(2+)的新方法.

The catalytic activity of nanozymes is largely dependent on the crystal structure and physicochemical properties of nanomaterials.In this study,three kinds of ferric oxyhydroxide(α-FeOOH,β-FeOOH,γ-FeOOH)nanoparticles with different crystal structures were synthesized in a controlled manner,and the difference of peroxidaselike activity and their mechanism were systematically studied.The results showed thatγ-FeOOH had higher peroxidaselike activity than the other two crystal structures,and its catalytic constants are 2.0 and 2.6 times those ofα-FeOOH andβ-FeOOH,respectively,which was attributed to the higher Fe^(2+)/Fe^(3+)ratio on the surface ofγ-FeOOH than that ofα-FeOOH andβ-FeOOH.Further,based on the excellent peroxidase-like activity ofγ-FeOOH,a new rapid,highly sensitive and selective fluorescence method was established for the detection of Hg^(2+)with vitamin B1 as a substrate.The detection range is 10-100 nM and the detection limit is 2 nM.This method has been applied to the determination of Hg^(2+)content in daily-used cosmetics.This work provides an effective way to obtain enzyme mimics with high catalytic activity by regulating crystal structure,and develops a new method for detecting Hg^(2+)based on the principle of nanozyme catalysis.