Multi-enzyme mimic Mn<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub> nanoparticles for efficient anti-inflammation therapy.

Abstract

The global prevalence of gingivitis has raised the cost considerably for extensive healthcare and refractory management, which is often accompanied by excessive accumulation of reactive oxygen species (ROS) that are considered to play a pivotal role in the development of gingivitis and other inflammatory diseases. Ordinary medications for the treatment of gingivitis, such as chemical anti-inflammatory or antimicrobial agents, are sometimes unsatisfactory due to rapid pathogen consumption and metabolism. To this end, new strategies and platforms are thus needed for the treatment of such ROS-related diseases. Herein, Mn₃O₄@SiO₂ NPs were designed and prepared through an <i>in situ</i> templating method and were found to possess over 2.5 times the <i>in vivo</i> antioxidant removal capacity and a 3-fold TNF (tumor necrosis factor)-α sequestration efficacy when compared with Mn₃O₄ NPs at the same concentration of Mn₃O₄. This was achieved through efficient catalytic ROS scavenging, thanks to the enlargement of the surface area and the enhanced dispersity and stabilization of the mesoporous SiO₂-supported Mn₃O₄ NPs. Furthermore, 65% of the IL (interleukin)-1β was down-regulated by the Mn₃O₄@SiO₂ NPs compared with an untreated gingivitis mouse model group, and in contrast, the IL-1β suppression rate for the iso-stoichiometric Mn₃O₄ NPs was about 85%. The multi-enzyme mimicking Mn₃O₄@SiO₂ NPs provided satisfactory biosafety and therapeutic effects in a gingivitis mouse model and thus represent a promising therapeutic platform for treating gingivitis and other inflammatory diseases.