Ultrasmall ruthenium nanoparticles with enhanced and tunable multienzyme-like activity for periodontitis treatment

Periodontitis is an inflammatory disease caused by oxidative stress and initiated by bacterial infection. The endogenous enzyme system is dysfunctional in the periodontitis microenvironment. Currently, traditional clinical treatment cannot efficiently eliminate bacteria or relieve inflammation. To address this issue, we developed ultrasmall ruthenium nanoparticles (US-RuNPs) with multienzyme-like activity. Our results indicated that US-RuNPs with an amplified electric field had a superior photothermal effect to large-sized RuNPs. Thus, US-RuNPs, through photothermal therapy (PTT), acted as “bacterial lysozyme” to eliminate planktonic pathogens and biofilms. In addition, the antioxidant enzyme-like activity of US-RuNPs was greater than that of large-sized RuNPs, and US-RuNPs could scavenge intracellular reactive oxygen species (ROS) and inhibit inflammation-related responses. More importantly, US-RuNPs demonstrated a satisfactory effect against periodontitis in vivo due to their synergistic antibacterial activity through PTT and antioxidant effects even in deep sites, decreasing the alveolar bone loss to root length ratio (ABL/RL) from 70.70% to 20.15% and increasing the collagen volume fraction from 16.88% to 57.64%. Thus, US-RuNPs with approximately 2 nm diameter, mimicking multienzyme activity, have great potential for the treatment of periodontitis.