化学
催化作用
锰
氧化剂
光化学
二价
无机化学
单线态氧
电子转移
电化学
组合化学
氧气
电极
有机化学
物理化学
作者
Jinyi Zhang,Shihong Wu,Xiaomei Lü,Peng Wu,Juewen Liu
出处
期刊:Nano Letters
[American Chemical Society]
日期:2019-04-09
卷期号:19 (5): 3214-3220
被引量:189
标识
DOI:10.1021/acs.nanolett.9b00725
摘要
A long-standing challenge in nanozyme catalysis is low activity at physiological pH, especially for oxidase- and peroxidase-mimicking nanozymes. We herein communicate that Mn(II) can promote catalysis at neutral pH for carbon dots (C-dots) as a photo-oxidase nanozyme. The C-dots produce singlet oxygen upon light irradiation to oxidize Mn(II) to Mn(III), which is confirmed by a suite of spectroscopic evidence. The in situ produced Mn(III) acts as a mediator, analogous to mediators in electrochemistry to enhance electron transfer. None of the other divalent metal ions show such an effect, allowing the selective detection of Mn(II) down to 5 nM. EDTA further enhances the activity by stabilizing the highly active Mn(III), producing an intense blue color by oxidizing 3,3′,5,5′-tetramethylbenzidine (TMB) in just 10 s. Finally, this reaction was used to evaluate antioxidants. With this method, more analytical and biomedical applications of nanozymes can be exploited at neutral pH, and it may inspire other strategies to overcome the pH limitation in nanozyme catalysis.
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