Chlorite-incorporated clay nanosheets as acid and H2O2-activated gas-bombs for combating peri-implant infection

Abstract

Persistent and recurrent bacterial infections pose significant challenges during the repair and reconstruction of bone defects, necessitating the development of effective solutions to this problem. Herein, a chlorine dioxide delivery platform (LDH@Cl) comprising chlorite-incorporated clay nanosheets (MgFe layered double hydroxides, MgFe LDH) is designed and constructed. The LDH@Cl gas bomb exploits self-promoted chemical reactions in an acidic and H2O2-rich microenvironment, generating substantial amounts of ClO2 and ·OH, which exhibit potent antibacterial activity. LDH@Cl exhibits half-maximal inhibitory concentrations of 0.69 mM and 0.78 mM against Escherichia coli and Staphylococcus aureus, respectively. Furthermore, LDH@Cl exhibits good biocompatibility at a low concentration of 0.08 mM; and significant osteogenic induction effects at a high concentration of 0.8 mM, which is attributed to the release of Mg ions and Fe ions in a normal microenvironment. Furthermore, LDH@Cl promotes the expression of the osteogenic channel signaling protein BMP2, which stimulates the expression of the downstream signaling factors SMAD1, SMAD2, and SMAD3, thereby regulating the synthesis of osteogenic-related proteins. Importantly, in vivo studies demonstrate the positive therapeutic effects of LDH@Cl in bacterial eradication and accelerated osteogenesis. Thus, this novel nano “gas bomb” is promising for the clinical treatment of bacterial infection related bone defect regeneration.