Magnetically retained and glucose-fueled hydroxyl radical nanogenerators for H2O2-self-supplying chemodynamic therapy of wound infections

Chemodynamic therapy (CDT) involving the highly toxic hydroxyl radical ( OH) has exhibited tremendous potentiality in combating bacterial infection. However, its antibacterial efficacy is still unsatisfactory due to the insufficient H 2 O 2 levels and near neutral pH at infection site. Herein, a glucose-fueled and H 2 O 2 -self-supplying OH nanogenerator (pFe 3 O 4 @GOx) based on cascade catalytic reactions is developed by immobilizing glucose oxidase (GOx) on the surface of PAA-coated Fe 3 O 4 (pFe 3 O 4 ). Magnetic pFe 3 O 4 can act as a horseradish peroxidase-like nanozyme, catalyzing the decomposition of H 2 O 2 into OH under acidic conditions for CDT. The immobilized GOx can continuously convert non-toxic glucose into gluconic acid and H 2 O 2 , and the former improves the catalytic activity of pFe 3 O 4 nanozymes by decreasing pH value. The self-supplying H 2 O 2 molecules effectively enhance the OH generation, resulting in the high antibacterial efficacy. In vitro studies demonstrate that the pFe 3 O 4 @GOx conducts well in reducing pH value and improving H 2 O 2 level for self-enhanced CDT. Moreover, the cascade catalytic reaction of pFe 3 O 4 and GOx effectively avoids strong toxicity caused by directly adding high concentrations of H 2 O 2 for CDT. It is worth mentioning that the pFe 3 O 4 @GOx performs highly efficient in vivo CDT of bacteria-infected wound via the localized long-term magnetic retention at infection site and causes minimal toxicity to normal tissues at therapeutic doses. Therefore, the developed glucose-fueled OH nanogenerators are a potential nano-antibacterial agent for the treatment of wound infections.