Trap & kill: a neutrophil-extracellular-trap mimic nanoparticle for anti-bacterial therapy.

Fenton chemistry-mediated antimicrobials have demonstrated great promise in antibacterial therapy. However, the short life span and diffusion distance of hydroxyl radicals dampen the therapeutic efficiency of these antimicrobials. Herein, inspired by the neutrophil extracellular trap (NET), in which bacteria are trapped and agglutinated via electronic interactions and killed by reactive oxygen species, we fabricated a NET-mimic nanoparticle to suppress bacterial infection in a "trap & kill" manner. Specifically, this NET-mimic nanoparticle was synthesized via polymerization of ferrocene monomers followed by quaternization with a mannose derivative. Similar to the NET, the NET-mimic nanoparticles trap bacteria through electronic and sugar-lectin interactions between their mannose moieties and the lectins of bacteria, forming bacterial agglutinations. Therefore, they confine the spread of the bacteria and restrict the bacterial cells to the destruction range of hydroxyl radicals. Meanwhile, the ferrocene component of the nanoparticle catalyzes the production of highly toxic hydroxyl radicals at the H2O2 rich infection foci and effectively eradicates the agglutinated bacteria. In a mouse model of an antimicrobial-resistant bacteria-infected wound, the NET-mimic nanoparticles displayed potent antibacterial activity and accelerated wound healing.