Fe-caffeic acid metal–polyphenol networks as acid-sensitive and self-enhanced chemodynamic agents against Staphylococcus aureus

The emergence of antibiotic resistance represents a significant and growing threat to global public health. The development of novel and antibiotic-free antibacterial strategies is therefore highly importance. In this context, chemodynamic therapy (CDT), which is based on Fenton or Fenton-like chemistry, is a promising strategy. CDT utilizes Fe 2+ to convert H 2 O 2 into highly reactive hydroxyl radicals (•OH), which can oxidize biomolecules to achieve antibacterial effects. The antibacterial efficacy of CDT is contingent upon both the catalyst and substrate. We developed a straightforward, convenient and economical approach to fabricate Fe-caffeic acid metal–polyphenol networks (Fe-CA MPNs) by mixing CA and Fe 3+ . The Fe-CA MPNs are acid-sensitive and self-enhanced CDT agents with remarkable antibacterial efficacy against both Staphylococcus aureus ( S. aureus ) and methicillin-resistant S. aureus (MRSA). Antibacterial efficacy was evaluated via a variety of methods, including the zone of inhibition, spread plate, turbidimetric, and live/dead bacterial staining tests. Specifically, the inhibition rates of Fe-CA MPNs for S. aureus and MRSA were 96.33 ± 0.33 % and 96.33 ± 0.15 %, respectively. CaO 2 @Fe-CA nanocomposites with H 2 O 2 self-supply properties were synthesized by depositing Fe-CA MPNs on the surface of CaO 2 nanoparticles which function as a sustained-release source of H 2 O 2 . The antibacterial effect of the CaO 2 @Fe-CA nanocomposites was comparable to that of Fe-CA MPNs combined with H 2 O 2 . Both Fe-CA MPNs and CaO 2 @Fe-CA possess favorable in vitro biosafety profiles. This work will facilitate the development of innovative antibiotic-free CDT antibacterial strategies based on •OH.