Surface ligand-regulated nanointerfaces: Enhancing the catalytic activity and selectivity of platinum nanozymes for biomedical applications

Platinum nanoparticles (Pt NPs) have aroused tremendous attention due to the significant enzyme-like activity, controllable synthesis and biosafety. However, it remains a challenge to properly design the morphology and surface properties of Pt NPs to obtain the desired enzyme-like activity and substrate selectivity. Herein, a surface engineering strategy is employed to adjust the catalytic performance of Pt NPs by modifying different functional groups, thereby promoting its oxidase-like activity and catalytic specificity to substrate. The catalytic performance of Pt NPs with various thiolate ligands was evaluated using TMB, ABTS and OPD as substrates. The kcat/Km values revealed that Pt NPs modified by 6-mercapto-6-deoxybeta-cyclodextrin (Pt@CD) had a strong substrate selectivity for TMB, but a weak selectivity for ABTS and OPD, with a catalytic specificity to TMB nearly 3.4 times that of bare Pt NPs. When uric acid was used as substrate, PtNP_32 showed better environmental stability and uric acid degradation efficiency than uricase. More importantly, the PtNP_32 did not cause hemolysis and had good biocompatibility, making it a promising candidate for the treatment of hyperuricemia-related diseases. This work provides a new strategy to improve the catalytic performance of platinum nanozymes for efficient and selective degradation of uric acid.