ATP-enhanced platinum nanoparticle's peroxidase activity in alkaline environment for simplifying alkaline phosphatase detection

Abstract

In recent years, a new method has been developed for the quantitative detection of alkaline phosphatase (ALP) based on the signal-off principle using oxidase or peroxidase nanozymes. However, the nanozymes used usually lose their activity under alkaline conditions, making it difficult to match the pH for ALP-catalyzed hydrolysis. Consequently, this detection method requires additional pH adjustment, which complicates the detection process and makes it prone to errors. In this study, we explored the enhancing effect of adenosine triphosphate (ATP) on the peroxidase (POD) activity of platinum nanoparticles formed with different protectants (Pt-CS NPs, Pt-PVP NPs, and Pt-BSA NPs) under neutral and alkaline conditions. It was found that ATP enhanced the POD activity of positively charged Pt-CS NPs the most, manifested as a significant increase in the maximum reaction rate (V_max). Based on the enhanced alkaline catalytic effect of ATP on Pt-CS NPs, we used Pt-CS/ATP as a new peroxidase nanozyme system. This system can catalyze at pH 8.5, enabling the detection of ALP without the need for pH adjustment. The research shows that the linear range of this detection system is 5–120 U/L, and the detection limit is 0.5 U/L. This study confirms that ATP can enhance the catalytic activity of platinum nanoparticles under neutral and alkaline conditions, providing a feasible solution for the direct detection of ALP under alkaline conditions using nanozymes.