A H2O2-free depot for treating bacterial infection: localized cascade reactions to eradicate biofilms in vivo

Peroxidase-like nanoparticles are promising materials to treat bacterial infection through catalyzing H2O2 into more toxic highly reactive oxygen species (hROS; such as hydroxyl radicals). However, all the reported related strategies, to the best of our knowledge, depend on the usage of extra H2O2, limiting the applications of peroxidase-like nanoparticles. Thus, it is necessary to develop peroxidase-based materials without extra H2O2. In this report, H2O2-free depots are prepared by integrating CaO2 and hemin-loading graphene (H-G) into alginate (CaO2/H-G@alginate). They can convert H2O into hROS through localized cascade reactions at the site of bacterial infection and damage the main components of biofilms (bacteria, polysaccharides, proteins, and nucleic acids). Besides, the confined environment of depots can reduce the potential risk from H2O2 and improve the cascade catalytic activity. This is the first example of exploring peroxidase-like nanozymes without extra H2O2 to treat bacterial infection.