Nano-sized platinum as a mimic of uricase catalyzing the oxidative degradation of uric acid

Abstract

Uric acid (UA) deposition in human body is very harmful, since it may induce gout. Therefore, it would be of great significance to catalyze the degradation of UA in human body. Herein, platinum nanoparticles (PtNPs) were found to be an effective mimic of uricase in the oxidation of UA. PtNPs could lower the activation energy of UA oxidation (i.e., from 139.49 kJ mol⁻¹ to 61.73 kJ mol⁻¹), and thus increase the reaction rate constant dramatically (e.g., by the catalysis of 2.63 mg L⁻¹ PtNPs, the reaction rate constant of UA degradation at 37 °C was 5.85 × 10⁻⁴ s⁻¹, which was almost 29000 times higher than that of without PtNPs (2.02 × 10⁻⁸ s⁻¹)). Effects of degradation conditions, such as the concentration and size of PtNPs, concentration of dissolved oxygen and pH value of the solution on the catalytic degradation of UA have been studied. Furthermore, products of UA degradation were analyzed by GC-MS spectroscopy and FT-IR spectrometry. On this basis, a detailed mechanism was finally proposed for the PtNPs-catalyzed UA degradation.