Ultrathin Ruthenium Nanosheets with Crystallinity-Modulated Peroxidase-like Activity for Protein Discrimination.

Noble-metal-based nanozymes have attracted great interest as enzyme mimics because of their unique properties. To modulate the performance and meet the requirements of practical biosensing applications, phase engineering is promising for the design of novel noble-metal-based nanomaterials. Herein, a simple salt-assist strategy was employed for the synthesis of Ru nanosheets (NSs) with the controlled crystalline degree. The crystalline degree plays a significant role in tuning peroxidase-like activity by optimizing the affinity toward the catalytic substrate. Furthermore, the inhibition effect of mercapto molecules on the peroxidase-like activity of Ru NSs was investigated. As a proof-of-concept, the Ru NSs-based colorimetric sensing arrays were developed to distinguish mercapto molecules, and five model molecules were well classified according to the different inhibition effects. Given the complexity of practical conditions, the sensing array was further applied to discriminate proteins possessing rich mercapto groups. This work not only provides an effective strategy for the design of highly active nanozymes but also achieves promising sensing arrays for practical needs.