The peroxidase and oxidase-like activity of NiCoO mesoporous spheres: Mechanistic understanding and colorimetric biosensing.

The synthesized NiCoO mesoporous spheres (MS) displayed intrinsic peroxidase and oxidase-like activity were firstly reported. The catalytic mechanism of the oxidase-like activity of NiCoO MS was analyzed in detail using the electron spin resonance (ESR) method. It is found that NiCoO MS could directly oxidize 3,3',5,5'-tetramethylbenzidine (TMB) but did not produce O and ·OH. And the mechanism of the peroxidase-like activity of NiCoO MS was also verified that the oxidation of TMB stemmed from not only ·OH but also O. Based on the NiCoO MS showed excellent peroxidase-like activity over a broad temperature range, especially at normal body temperature, a detection tool was designed for glucose determination in diabetics' serum samples. And this detection method based on NiCoO MS gave a lower limit of detection than the method using CoO NPs and NiO NPs, as the single-component oxides of NiCoO. Our study may open up the possibility to make a great influence on the next generation of enzyme mimetics system.