Single-holed cobalt − nitrogen − carbon hollow structure with oxidase-mimicking activity for the chemiluminescence determination of β − galactosidase activity

A single-holed cobalt − nitrogen − carbon (Co − N − C) hollow structure nanozyme has been fabricated by in situ growth of zeolitic imidazolate framework (ZIF − 67) on the polystyrene (PS) sphere and following treatment by high-temperature carbonization. The Co − N − C nanostructure mimics the activity of oxidase and can activate O₂ into reactive oxygen species (ROS), giving a remarkable enhancement on the chemiluminescence (CL) signal of luminol − O₂ reaction. The Co − N − C oxidase mimic has further been exploited in the biosensing field by the determination of the activity of β − galactosidase (β − gal). The CL method for β − gal activity has a linear range of 0.5 mU·L⁻¹ to 5.0 U·L⁻¹, a detection limit of 0.167 mU·L⁻¹, and the precision of 3.1% (5.0 U·L⁻¹, n = 11). This method has been employed to assess inhibitor screening of β − gal and determine activity of β − gal in spiked human serum samples.