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Nano Research

Article Title

Effects of crystal structure on the activity of MnO2 nanorods oxidase mimics

Authors

Yanxia Meng, School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai 200093, China Shanghai University of Medicine and Health Sciences, 279 Zhouzhu Road, Shanghai 201318, China
Kunfeng Zhao, School of Materials Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China National Engineering Research Center for Nanotechnology, 28 East Jiangchuan Road, Shanghai 200241, China Shanghai University of Medicine and Health Sciences, 279 Zhouzhu Road, Shanghai 201318, China
Zhaokun Zhang, School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai 200093, China Shanghai University of Medicine and Health Sciences, 279 Zhouzhu Road, Shanghai 201318, China
Peng Gao, Ningbo Fundenergy Co., Ltd., 699 Haicheng Road, Ningbo 315200, China
Jing Yuan, National Engineering Research Center for Nanotechnology, 28 East Jiangchuan Road, Shanghai 200241, China
Ting Cai, National Engineering Research Center for Nanotechnology, 28 East Jiangchuan Road, Shanghai 200241, China
Qin Tong, National Engineering Research Center for Nanotechnology, 28 East Jiangchuan Road, Shanghai 200241, China
Gang Huang, Shanghai University of Medicine and Health Sciences, 279 Zhouzhu Road, Shanghai 201318, China
Dannong He, School of Materials Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China Shanghai University of Medicine and Health Sciences, 279 Zhouzhu Road, Shanghai 201318, China

Keywords

crystal phase structure, MnO2, oxidase mimics, surface hydroxyls, 3, 3', 5, 5'-tetramethylbenzidine (TMB), glutathione

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 mol·m−2·s−1, 2.7 and 19.0 times of those of α-MnO2 and γ-MnO2 (30.91 and 4.41 mol·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.

Graphical Abstract

Publisher

Tsinghua University Press

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