Versatile graphitic nanozymes for magneto actuated cascade reaction-enhanced treatment of S. mutans biofilms

Pathogenic oral biofilms especially acid-producing ones cause a variety of oral diseases such as dental caries. Given that bacteria are embedded within the biofilms matrix to prevent the penetration of therapeutic drugs, people have explored the applications of nanoparticles to treat oral diseases. However, current nanoparticle-mediated eradication has not achieved the precise treatment of biofilms, and the stabilities of nanoparticles go on strike because of acidic environment leading to poor therapeutic effectiveness. Herein, we design an integrated nanozyme, CoPt@graphene@glucose oxidase (CoPt@G@GOx), which has cascade reaction activity with two-step process. Hydrogen peroxide (H2O2) produced through the glucose oxidation by GOx serves as the substrate for peroxidase-mimic CoPt@G to produce highly toxic hydroxyl radical under acidic environment. Compared to the simple mixture of GOx and CoPt@G, CoPt@G@GOx shows around fourfold catalytic effect enhancement. Meanwhile, CoPt@G@GOx can precisely target the location of the biofilms, which ensures the minimal impact on normal soft-tissues. Relying on the advantage of the magneto-actuated cascade catalytic activity, CoPt@G@GOx reveals a superior antibacterial ability in the Streptococcus mutans biofilms model. Thus, our results provide an easy and effective method to exploit bifunctional nanozyme as a novel topical agent to prevent the prevalent biofilm-induced oral disease.