Nanozymes have emerged as promising therapeutic agents, but clinical translation remains hindered by limited catalytic efficiency, structural disorder, and single-function activity. An atomic-level ordered platinum-cobalt (Pt-Co) nanozyme was designed to overcome these limitations, achieving enhanced catalytic performance and multifunctional bioactivity. The highly uniform L1₀-type Pt-Co structure, featuring strong electronic coupling and lattice strain effects between Pt and Co, synergistically lowers reaction energy barriers, thereby significantly enhancing superoxide dismutase (SOD)- and catalase (CAT)-like activities for rapid scavenging of reactive oxygen species (ROS), as evidenced by 82% SOD-like inhibition (vs 46% for Pt-C catalysts) and a doubled H₂O₂ decomposition rate. In vitro and in vivo studies demonstrated that the nanozyme attenuated ROS-induced inflammation by shifting macrophage polarization from pro-inflammatory M1 to anti-inflammatory M2 (ROS-positive macrophages decreased from 98.1% to 29.5%), reducing inflammatory cytokine production and activating Nrf2/NF-κB signaling. Moreover, Co endowed the nanozyme with osteogenic capabilities by upregulating osteogenic gene expression, including a twofold increase in Runx2, substantially promoting bone regeneration in a mouse model of periodontitis. The dual-metal nanozyme thus serves as a versatile therapeutic platform, simultaneously addressing ROS accumulation, inflammation, and bone resorption, and offers a promising advance in the treatment of periodontitis and other oxidative stress-related diseases.

Optimization of Pt atom utilization efficiency is critical for the development of proton-exchange-membrane fuel cells. Here we aim to develop an efficient oxygen reduction reaction (ORR) catalyst with a low Pt content through the concurrent modification of Pt-Co alloy catalysts and carbon substrate. In the present study, ultrafine Pt-Co alloy nanoparticles are successfully synthesized and stabilized by topological carbon defects via adopting the ammonia thermal treatment. Despite the low Pt loading, the obtained catalyst exhibits an impressive half-wave potential of 0.926 V versus the reversible hydrogen electrode in 0.1 M HClO₄ electrolyte. Furthermore, the durability testing using the timed-current method demonstrates a tiny loss of only 3.6% after 12 h. Both experimental results and theoretical calculations demonstrate that topological carbon defects significantly enhance the charge transfer processes at the alloy/carbon interface, contributing to the strong electronic metal-support interactions between the Pt-Co alloy nanoparticles and topological carbon defects. These interactions, along with the alloy effect, play a crucial role in promoting the ORR performance in acidic media.