Spectrophotometric Determination of Alkaline Phosphatase in Serum by A Copper Prussian Blue Analog as A Novel Polyphenol Oxidase-Like Nanozyme

Abstract

Nanomaterials with natural enzyme-like activities have attracted widespread interest and hence their development is significant. Here, a copper Prussian blue analogue named Cu-HCF was prepared and its polyphenol oxidase (PPO)-like activity was investigated for the first time. Cu-HCF nanozyme showed nearly 7-fold higher substrate affinity than natural PPO and was more stable under alkaline conditions, high temperature, high salt concentrations, and long-time storage. The catalytic activity of Cu-HCF nanozyme was reduced by pyrophosphate (PPi). Alkaline phosphatase (ALP) hydrolyzed PPi to orthophosphate (Pi) and hence the PPO-like activity of Cu-HCF nanozyme was restored. A method was therefore developed for selective determination of the ALP activity. The linear range was from 1 to 50 mU/mL with a limit of detection (LOD) of 0.35 mU/mL. This approach was validated in human serum samples, showing its potential in diagnostic applications.

Keywords:

• Alkaline phosphatase
• copper Prussian blue analogue
• nanozyme
• polyphenol oxidase
• spectrophotometry

Disclosure statement

The authors declare that they have no competing interests.

Additional information

Funding

This work was financially supported by the National Natural Science Foundation of China (22176069), Natural Science Foundation of Jilin Province (20220101042JC and 20220101263JC), and the China Postdoctoral Science Foundation (2021M691199).