Biomimetic design for enhancing the peroxidase mimicking activity of hemin

Although various nanomaterials have been found to exhibit intrinsic enzyme-like activity, to date, there is no general strategy for designing nanozymes, and their catalytic mechanism has not been studied in depth. To realize the desired enzymatic properties, imitating the structure of natural enzymes is a commendable way to develop effective nanozymes. Inspired by the structure of natural horseradish peroxidase (HRP), we loaded hemin onto amino-modified single-walled carbon nanotubes (SWNT-NH₂) to prepare an effective peroxidase-like nanozyme (SWNT-NH₂@hemin). The peroxidase-like activity of hemin was enhanced by SWNT through π-π interactions, and the positively charged -NH₂ groups played a similar role to arginine in HRP and stabilized the intermediate during catalysis and facilitated the cleavage of the O-O bond. This is instructive for the development of a variety of highly efficient nanozymes by simulating the adjacent environment of the active center in natural enzymes. In addition, dual sensor platforms consisting of a colorimetric method and electrochemical method were developed based on SWNT-NH₂@hemin.